This document is free; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Kernel Hackers Manual July 2017 snd_device_initialize 9 4.1.27 snd_device_initialize Initialize struct device for sound devices void snd_device_initialize struct device * dev struct snd_card * card dev device to initialize card card to assign, optional Kernel Hackers Manual July 2017 snd_card_new 9 4.1.27 snd_card_new create and initialize a soundcard structure int snd_card_new struct device * parent int idx const char * xid struct module * module int extra_size struct snd_card ** card_ret parent the parent device object idx card index (address) [0 ... (SNDRV_CARDS-1)] xid card identification (ASCII string) module top level module for locking extra_size allocate this extra size after the main soundcard structure card_ret the pointer to store the created card instance Creates and initializes a soundcard structure. The function allocates snd_card instance via kzalloc with the given space for the driver to use freely. The allocated struct is stored in the given card_ret pointer. Zero if successful or a negative error code. Kernel Hackers Manual July 2017 snd_card_disconnect 9 4.1.27 snd_card_disconnect disconnect all APIs from the file-operations (user space) int snd_card_disconnect struct snd_card * card card soundcard structure Disconnects all APIs from the file-operations (user space). Zero, otherwise a negative error code. The current implementation replaces all active file->f_op with special dummy file operations (they do nothing except release). Kernel Hackers Manual July 2017 snd_card_free_when_closed 9 4.1.27 snd_card_free_when_closed Disconnect the card, free it later eventually int snd_card_free_when_closed struct snd_card * card card soundcard structure Unlike snd_card_free, this function doesn't try to release the card resource immediately, but tries to disconnect at first. When the card is still in use, the function returns before freeing the resources. The card resources will be freed when the refcount gets to zero. Kernel Hackers Manual July 2017 snd_card_free 9 4.1.27 snd_card_free frees given soundcard structure int snd_card_free struct snd_card * card card soundcard structure This function releases the soundcard structure and the all assigned devices automatically. That is, you don't have to release the devices by yourself. This function waits until the all resources are properly released. Zero. Frees all associated devices and frees the control interface associated to given soundcard. Kernel Hackers Manual July 2017 snd_card_set_id 9 4.1.27 snd_card_set_id set card identification name void snd_card_set_id struct snd_card * card const char * nid card soundcard structure nid new identification string This function sets the card identification and checks for name collisions. Kernel Hackers Manual July 2017 snd_card_add_dev_attr 9 4.1.27 snd_card_add_dev_attr Append a new sysfs attribute group to card int snd_card_add_dev_attr struct snd_card * card const struct attribute_group * group card card instance group attribute group to append Kernel Hackers Manual July 2017 snd_card_register 9 4.1.27 snd_card_register register the soundcard int snd_card_register struct snd_card * card card soundcard structure This function registers all the devices assigned to the soundcard. Until calling this, the ALSA control interface is blocked from the external accesses. Thus, you should call this function at the end of the initialization of the card. Zero otherwise a negative error code if the registration failed. Kernel Hackers Manual July 2017 snd_component_add 9 4.1.27 snd_component_add add a component string int snd_component_add struct snd_card * card const char * component card soundcard structure component the component id string This function adds the component id string to the supported list. The component can be referred from the alsa-lib. Zero otherwise a negative error code. Kernel Hackers Manual July 2017 snd_card_file_add 9 4.1.27 snd_card_file_add add the file to the file list of the card int snd_card_file_add struct snd_card * card struct file * file card soundcard structure file file pointer This function adds the file to the file linked-list of the card. This linked-list is used to keep tracking the connection state, and to avoid the release of busy resources by hotplug. zero or a negative error code. Kernel Hackers Manual July 2017 snd_card_file_remove 9 4.1.27 snd_card_file_remove remove the file from the file list int snd_card_file_remove struct snd_card * card struct file * file card soundcard structure file file pointer This function removes the file formerly added to the card via snd_card_file_add function. If all files are removed and snd_card_free_when_closed was called beforehand, it processes the pending release of resources. Zero or a negative error code. Kernel Hackers Manual July 2017 snd_power_wait 9 4.1.27 snd_power_wait wait until the power-state is changed. int snd_power_wait struct snd_card * card unsigned int power_state card soundcard structure power_state expected power state Waits until the power-state is changed. Zero if successful, or a negative error code. the power lock must be active before call. Kernel Hackers Manual July 2017 snd_device_new 9 4.1.27 snd_device_new create an ALSA device component int snd_device_new struct snd_card * card enum snd_device_type type void * device_data struct snd_device_ops * ops card the card instance type the device type, SNDRV_DEV_XXX device_data the data pointer of this device ops the operator table Creates a new device component for the given data pointer. The device will be assigned to the card and managed together by the card. The data pointer plays a role as the identifier, too, so the pointer address must be unique and unchanged. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_device_disconnect 9 4.1.27 snd_device_disconnect disconnect the device void snd_device_disconnect struct snd_card * card void * device_data card the card instance device_data the data pointer to disconnect Turns the device into the disconnection state, invoking dev_disconnect callback, if the device was already registered. Usually called from snd_card_disconnect. Zero if successful, or a negative error code on failure or if the device not found. Kernel Hackers Manual July 2017 snd_device_free 9 4.1.27 snd_device_free release the device from the card void snd_device_free struct snd_card * card void * device_data card the card instance device_data the data pointer to release Removes the device from the list on the card and invokes the callbacks, dev_disconnect and dev_free, corresponding to the state. Then release the device. Kernel Hackers Manual July 2017 snd_device_register 9 4.1.27 snd_device_register register the device int snd_device_register struct snd_card * card void * device_data card the card instance device_data the data pointer to register Registers the device which was already created via snd_device_new. Usually this is called from snd_card_register, but it can be called later if any new devices are created after invocation of snd_card_register. Zero if successful, or a negative error code on failure or if the device not found. Kernel Hackers Manual July 2017 snd_request_card 9 4.1.27 snd_request_card try to load the card module void snd_request_card int card card the card number Tries to load the module snd-card-X for the given card number via request_module. Returns immediately if already loaded. Kernel Hackers Manual July 2017 snd_lookup_minor_data 9 4.1.27 snd_lookup_minor_data get user data of a registered device void * snd_lookup_minor_data unsigned int minor int type minor the minor number type device type (SNDRV_DEVICE_TYPE_XXX) Checks that a minor device with the specified type is registered, and returns its user data pointer. This function increments the reference counter of the card instance if an associated instance with the given minor number and type is found. The caller must call snd_card_unref appropriately later. The user data pointer if the specified device is found. NULL otherwise. Kernel Hackers Manual July 2017 snd_register_device 9 4.1.27 snd_register_device Register the ALSA device file for the card int snd_register_device int type struct snd_card * card int dev const struct file_operations * f_ops void * private_data struct device * device type the device type, SNDRV_DEVICE_TYPE_XXX card the card instance dev the device index f_ops the file operations private_data user pointer for f_ops->open device the device to register Registers an ALSA device file for the given card. The operators have to be set in reg parameter. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_unregister_device 9 4.1.27 snd_unregister_device unregister the device on the given card int snd_unregister_device struct device * dev dev the device instance Unregisters the device file already registered via snd_register_device. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 copy_to_user_fromio 9 4.1.27 copy_to_user_fromio copy data from mmio-space to user-space int copy_to_user_fromio void __user * dst const volatile void __iomem * src size_t count dst the destination pointer on user-space src the source pointer on mmio count the data size to copy in bytes Copies the data from mmio-space to user-space. Zero if successful, or non-zero on failure. Kernel Hackers Manual July 2017 copy_from_user_toio 9 4.1.27 copy_from_user_toio copy data from user-space to mmio-space int copy_from_user_toio volatile void __iomem * dst const void __user * src size_t count dst the destination pointer on mmio-space src the source pointer on user-space count the data size to copy in bytes Copies the data from user-space to mmio-space. Zero if successful, or non-zero on failure. Kernel Hackers Manual July 2017 snd_malloc_pages 9 4.1.27 snd_malloc_pages allocate pages with the given size void * snd_malloc_pages size_t size gfp_t gfp_flags size the size to allocate in bytes gfp_flags the allocation conditions, GFP_XXX Allocates the physically contiguous pages with the given size. The pointer of the buffer, or NULL if no enough memory. Kernel Hackers Manual July 2017 snd_free_pages 9 4.1.27 snd_free_pages release the pages void snd_free_pages void * ptr size_t size ptr the buffer pointer to release size the allocated buffer size Releases the buffer allocated via snd_malloc_pages. Kernel Hackers Manual July 2017 snd_dma_alloc_pages 9 4.1.27 snd_dma_alloc_pages allocate the buffer area according to the given type int snd_dma_alloc_pages int type struct device * device size_t size struct snd_dma_buffer * dmab type the DMA buffer type device the device pointer size the buffer size to allocate dmab buffer allocation record to store the allocated data Calls the memory-allocator function for the corresponding buffer type. Zero if the buffer with the given size is allocated successfully, otherwise a negative value on error. Kernel Hackers Manual July 2017 snd_dma_alloc_pages_fallback 9 4.1.27 snd_dma_alloc_pages_fallback allocate the buffer area according to the given type with fallback int snd_dma_alloc_pages_fallback int type struct device * device size_t size struct snd_dma_buffer * dmab type the DMA buffer type device the device pointer size the buffer size to allocate dmab buffer allocation record to store the allocated data Calls the memory-allocator function for the corresponding buffer type. When no space is left, this function reduces the size and tries to allocate again. The size actually allocated is stored in res_size argument. Zero if the buffer with the given size is allocated successfully, otherwise a negative value on error. Kernel Hackers Manual July 2017 snd_dma_free_pages 9 4.1.27 snd_dma_free_pages release the allocated buffer void snd_dma_free_pages struct snd_dma_buffer * dmab dmab the buffer allocation record to release Releases the allocated buffer via snd_dma_alloc_pages. Kernel Hackers Manual July 2017 snd_pcm_format_name 9 4.1.27 snd_pcm_format_name Return a name string for the given PCM format const char * snd_pcm_format_name snd_pcm_format_t format format PCM format Kernel Hackers Manual July 2017 snd_pcm_new_stream 9 4.1.27 snd_pcm_new_stream create a new PCM stream int snd_pcm_new_stream struct snd_pcm * pcm int stream int substream_count pcm the pcm instance stream the stream direction, SNDRV_PCM_STREAM_XXX substream_count the number of substreams Creates a new stream for the pcm. The corresponding stream on the pcm must have been empty before calling this, i.e. zero must be given to the argument of snd_pcm_new. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_new 9 4.1.27 snd_pcm_new create a new PCM instance int snd_pcm_new struct snd_card * card const char * id int device int playback_count int capture_count struct snd_pcm ** rpcm card the card instance id the id string device the device index (zero based) playback_count the number of substreams for playback capture_count the number of substreams for capture rpcm the pointer to store the new pcm instance Creates a new PCM instance. The pcm operators have to be set afterwards to the new instance via snd_pcm_set_ops. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_new_internal 9 4.1.27 snd_pcm_new_internal create a new internal PCM instance int snd_pcm_new_internal struct snd_card * card const char * id int device int playback_count int capture_count struct snd_pcm ** rpcm card the card instance id the id string device the device index (zero based - shared with normal PCMs) playback_count the number of substreams for playback capture_count the number of substreams for capture rpcm the pointer to store the new pcm instance Creates a new internal PCM instance with no userspace device or procfs entries. This is used by ASoC Back End PCMs in order to create a PCM that will only be used internally by kernel drivers. i.e. it cannot be opened by userspace. It provides existing ASoC components drivers with a substream and access to any private data. The pcm operators have to be set afterwards to the new instance via snd_pcm_set_ops. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_notify 9 4.1.27 snd_pcm_notify Add/remove the notify list int snd_pcm_notify struct snd_pcm_notify * notify int nfree notify PCM notify list nfree 0 = register, 1 = unregister This adds the given notifier to the global list so that the callback is called for each registered PCM devices. This exists only for PCM OSS emulation, so far. Kernel Hackers Manual July 2017 snd_pcm_set_ops 9 4.1.27 snd_pcm_set_ops set the PCM operators void snd_pcm_set_ops struct snd_pcm * pcm int direction const struct snd_pcm_ops * ops pcm the pcm instance direction stream direction, SNDRV_PCM_STREAM_XXX ops the operator table Sets the given PCM operators to the pcm instance. Kernel Hackers Manual July 2017 snd_pcm_set_sync 9 4.1.27 snd_pcm_set_sync set the PCM sync id void snd_pcm_set_sync struct snd_pcm_substream * substream substream the pcm substream Sets the PCM sync identifier for the card. Kernel Hackers Manual July 2017 snd_interval_refine 9 4.1.27 snd_interval_refine refine the interval value of configurator int snd_interval_refine struct snd_interval * i const struct snd_interval * v i the interval value to refine v the interval value to refer to Refines the interval value with the reference value. The interval is changed to the range satisfying both intervals. The interval status (min, max, integer, etc.) are evaluated. Positive if the value is changed, zero if it's not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_interval_ratnum 9 4.1.27 snd_interval_ratnum refine the interval value int snd_interval_ratnum struct snd_interval * i unsigned int rats_count struct snd_ratnum * rats unsigned int * nump unsigned int * denp i interval to refine rats_count number of ratnum_t rats ratnum_t array nump pointer to store the resultant numerator denp pointer to store the resultant denominator Positive if the value is changed, zero if it's not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_interval_list 9 4.1.27 snd_interval_list refine the interval value from the list int snd_interval_list struct snd_interval * i unsigned int count const unsigned int * list unsigned int mask i the interval value to refine count the number of elements in the list list the value list mask the bit-mask to evaluate Refines the interval value from the list. When mask is non-zero, only the elements corresponding to bit 1 are evaluated. Positive if the value is changed, zero if it's not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_interval_ranges 9 4.1.27 snd_interval_ranges refine the interval value from the list of ranges int snd_interval_ranges struct snd_interval * i unsigned int count const struct snd_interval * ranges unsigned int mask i the interval value to refine count the number of elements in the list of ranges ranges the ranges list mask the bit-mask to evaluate Refines the interval value from the list of ranges. When mask is non-zero, only the elements corresponding to bit 1 are evaluated. Positive if the value is changed, zero if it's not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_hw_rule_add 9 4.1.27 snd_pcm_hw_rule_add add the hw-constraint rule int snd_pcm_hw_rule_add struct snd_pcm_runtime * runtime unsigned int cond int var snd_pcm_hw_rule_func_t func void * private int dep ... runtime the pcm runtime instance cond condition bits var the variable to evaluate func the evaluation function private the private data pointer passed to function dep the dependent variables ... variable arguments Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_mask64 9 4.1.27 snd_pcm_hw_constraint_mask64 apply the given bitmap mask constraint int snd_pcm_hw_constraint_mask64 struct snd_pcm_runtime * runtime snd_pcm_hw_param_t var u_int64_t mask runtime PCM runtime instance var hw_params variable to apply the mask mask the 64bit bitmap mask Apply the constraint of the given bitmap mask to a 64-bit mask parameter. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_integer 9 4.1.27 snd_pcm_hw_constraint_integer apply an integer constraint to an interval int snd_pcm_hw_constraint_integer struct snd_pcm_runtime * runtime snd_pcm_hw_param_t var runtime PCM runtime instance var hw_params variable to apply the integer constraint Apply the constraint of integer to an interval parameter. Positive if the value is changed, zero if it's not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_minmax 9 4.1.27 snd_pcm_hw_constraint_minmax apply a min/max range constraint to an interval int snd_pcm_hw_constraint_minmax struct snd_pcm_runtime * runtime snd_pcm_hw_param_t var unsigned int min unsigned int max runtime PCM runtime instance var hw_params variable to apply the range min the minimal value max the maximal value Apply the min/max range constraint to an interval parameter. Positive if the value is changed, zero if it's not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_list 9 4.1.27 snd_pcm_hw_constraint_list apply a list of constraints to a parameter int snd_pcm_hw_constraint_list struct snd_pcm_runtime * runtime unsigned int cond snd_pcm_hw_param_t var const struct snd_pcm_hw_constraint_list * l runtime PCM runtime instance cond condition bits var hw_params variable to apply the list constraint l list Apply the list of constraints to an interval parameter. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_ranges 9 4.1.27 snd_pcm_hw_constraint_ranges apply list of range constraints to a parameter int snd_pcm_hw_constraint_ranges struct snd_pcm_runtime * runtime unsigned int cond snd_pcm_hw_param_t var const struct snd_pcm_hw_constraint_ranges * r runtime PCM runtime instance cond condition bits var hw_params variable to apply the list of range constraints r ranges Apply the list of range constraints to an interval parameter. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_ratnums 9 4.1.27 snd_pcm_hw_constraint_ratnums apply ratnums constraint to a parameter int snd_pcm_hw_constraint_ratnums struct snd_pcm_runtime * runtime unsigned int cond snd_pcm_hw_param_t var struct snd_pcm_hw_constraint_ratnums * r runtime PCM runtime instance cond condition bits var hw_params variable to apply the ratnums constraint r struct snd_ratnums constriants Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_ratdens 9 4.1.27 snd_pcm_hw_constraint_ratdens apply ratdens constraint to a parameter int snd_pcm_hw_constraint_ratdens struct snd_pcm_runtime * runtime unsigned int cond snd_pcm_hw_param_t var struct snd_pcm_hw_constraint_ratdens * r runtime PCM runtime instance cond condition bits var hw_params variable to apply the ratdens constraint r struct snd_ratdens constriants Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_msbits 9 4.1.27 snd_pcm_hw_constraint_msbits add a hw constraint msbits rule int snd_pcm_hw_constraint_msbits struct snd_pcm_runtime * runtime unsigned int cond unsigned int width unsigned int msbits runtime PCM runtime instance cond condition bits width sample bits width msbits msbits width This constraint will set the number of most significant bits (msbits) if a sample format with the specified width has been select. If width is set to 0 the msbits will be set for any sample format with a width larger than the specified msbits. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_step 9 4.1.27 snd_pcm_hw_constraint_step add a hw constraint step rule int snd_pcm_hw_constraint_step struct snd_pcm_runtime * runtime unsigned int cond snd_pcm_hw_param_t var unsigned long step runtime PCM runtime instance cond condition bits var hw_params variable to apply the step constraint step step size Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_constraint_pow2 9 4.1.27 snd_pcm_hw_constraint_pow2 add a hw constraint power-of-2 rule int snd_pcm_hw_constraint_pow2 struct snd_pcm_runtime * runtime unsigned int cond snd_pcm_hw_param_t var runtime PCM runtime instance cond condition bits var hw_params variable to apply the power-of-2 constraint Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_rule_noresample 9 4.1.27 snd_pcm_hw_rule_noresample add a rule to allow disabling hw resampling int snd_pcm_hw_rule_noresample struct snd_pcm_runtime * runtime unsigned int base_rate runtime PCM runtime instance base_rate the rate at which the hardware does not resample Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_param_value 9 4.1.27 snd_pcm_hw_param_value return params field var value int snd_pcm_hw_param_value const struct snd_pcm_hw_params * params snd_pcm_hw_param_t var int * dir params the hw_params instance var parameter to retrieve dir pointer to the direction (-1,0,1) or NULL The value for field var if it's fixed in configuration space defined by params. -EINVAL otherwise. Kernel Hackers Manual July 2017 snd_pcm_hw_param_first 9 4.1.27 snd_pcm_hw_param_first refine config space and return minimum value int snd_pcm_hw_param_first struct snd_pcm_substream * pcm struct snd_pcm_hw_params * params snd_pcm_hw_param_t var int * dir pcm PCM instance params the hw_params instance var parameter to retrieve dir pointer to the direction (-1,0,1) or NULL Inside configuration space defined by params remove from var all values > minimum. Reduce configuration space accordingly. The minimum, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_hw_param_last 9 4.1.27 snd_pcm_hw_param_last refine config space and return maximum value int snd_pcm_hw_param_last struct snd_pcm_substream * pcm struct snd_pcm_hw_params * params snd_pcm_hw_param_t var int * dir pcm PCM instance params the hw_params instance var parameter to retrieve dir pointer to the direction (-1,0,1) or NULL Inside configuration space defined by params remove from var all values < maximum. Reduce configuration space accordingly. The maximum, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_ioctl 9 4.1.27 snd_pcm_lib_ioctl a generic PCM ioctl callback int snd_pcm_lib_ioctl struct snd_pcm_substream * substream unsigned int cmd void * arg substream the pcm substream instance cmd ioctl command arg ioctl argument Processes the generic ioctl commands for PCM. Can be passed as the ioctl callback for PCM ops. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_period_elapsed 9 4.1.27 snd_pcm_period_elapsed update the pcm status for the next period void snd_pcm_period_elapsed struct snd_pcm_substream * substream substream the pcm substream instance This function is called from the interrupt handler when the PCM has processed the period size. It will update the current pointer, wake up sleepers, etc. Even if more than one periods have elapsed since the last call, you have to call this only once. Kernel Hackers Manual July 2017 snd_pcm_add_chmap_ctls 9 4.1.27 snd_pcm_add_chmap_ctls create channel-mapping control elements int snd_pcm_add_chmap_ctls struct snd_pcm * pcm int stream const struct snd_pcm_chmap_elem * chmap int max_channels unsigned long private_value struct snd_pcm_chmap ** info_ret pcm the assigned PCM instance stream stream direction chmap channel map elements (for query) max_channels the max number of channels for the stream private_value the value passed to each kcontrol's private_value field info_ret store struct snd_pcm_chmap instance if non-NULL Create channel-mapping control elements assigned to the given PCM stream(s). Zero if successful, or a negative error value. Kernel Hackers Manual July 2017 snd_pcm_stream_lock 9 4.1.27 snd_pcm_stream_lock Lock the PCM stream void snd_pcm_stream_lock struct snd_pcm_substream * substream substream PCM substream This locks the PCM stream's spinlock or mutex depending on the nonatomic flag of the given substream. This also takes the global link rw lock (or rw sem), too, for avoiding the race with linked streams. Kernel Hackers Manual July 2017 snd_pcm_stream_unlock 9 4.1.27 snd_pcm_stream_unlock Unlock the PCM stream void snd_pcm_stream_unlock struct snd_pcm_substream * substream substream PCM substream This unlocks the PCM stream that has been locked via snd_pcm_stream_lock. Kernel Hackers Manual July 2017 snd_pcm_stream_lock_irq 9 4.1.27 snd_pcm_stream_lock_irq Lock the PCM stream void snd_pcm_stream_lock_irq struct snd_pcm_substream * substream substream PCM substream This locks the PCM stream like snd_pcm_stream_lock and disables the local IRQ (only when nonatomic is false). In nonatomic case, this is identical as snd_pcm_stream_lock. Kernel Hackers Manual July 2017 snd_pcm_stream_unlock_irq 9 4.1.27 snd_pcm_stream_unlock_irq Unlock the PCM stream void snd_pcm_stream_unlock_irq struct snd_pcm_substream * substream substream PCM substream This is a counter-part of snd_pcm_stream_lock_irq. Kernel Hackers Manual July 2017 snd_pcm_stream_unlock_irqrestore 9 4.1.27 snd_pcm_stream_unlock_irqrestore Unlock the PCM stream void snd_pcm_stream_unlock_irqrestore struct snd_pcm_substream * substream unsigned long flags substream PCM substream flags irq flags This is a counter-part of snd_pcm_stream_lock_irqsave. Kernel Hackers Manual July 2017 snd_pcm_stop 9 4.1.27 snd_pcm_stop try to stop all running streams in the substream group int snd_pcm_stop struct snd_pcm_substream * substream snd_pcm_state_t state substream the PCM substream instance state PCM state after stopping the stream The state of each stream is then changed to the given state unconditionally. Zero if successful, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_stop_xrun 9 4.1.27 snd_pcm_stop_xrun stop the running streams as XRUN int snd_pcm_stop_xrun struct snd_pcm_substream * substream substream the PCM substream instance This stops the given running substream (and all linked substreams) as XRUN. Unlike snd_pcm_stop, this function takes the substream lock by itself. Zero if successful, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_suspend 9 4.1.27 snd_pcm_suspend trigger SUSPEND to all linked streams int snd_pcm_suspend struct snd_pcm_substream * substream substream the PCM substream After this call, all streams are changed to SUSPENDED state. Zero if successful (or substream is NULL), or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_suspend_all 9 4.1.27 snd_pcm_suspend_all trigger SUSPEND to all substreams in the given pcm int snd_pcm_suspend_all struct snd_pcm * pcm pcm the PCM instance After this call, all streams are changed to SUSPENDED state. Zero if successful (or pcm is NULL), or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_lib_default_mmap 9 4.1.27 snd_pcm_lib_default_mmap Default PCM data mmap function int snd_pcm_lib_default_mmap struct snd_pcm_substream * substream struct vm_area_struct * area substream PCM substream area VMA This is the default mmap handler for PCM data. When mmap pcm_ops is NULL, this function is invoked implicitly. Kernel Hackers Manual July 2017 snd_pcm_lib_mmap_iomem 9 4.1.27 snd_pcm_lib_mmap_iomem Default PCM data mmap function for I/O mem int snd_pcm_lib_mmap_iomem struct snd_pcm_substream * substream struct vm_area_struct * area substream PCM substream area VMA When your hardware uses the iomapped pages as the hardware buffer and wants to mmap it, pass this function as mmap pcm_ops. Note that this is supposed to work only on limited architectures. Kernel Hackers Manual July 2017 snd_pcm_stream_linked 9 4.1.27 snd_pcm_stream_linked Check whether the substream is linked with others int snd_pcm_stream_linked struct snd_pcm_substream * substream substream substream to check Returns true if the given substream is being linked with others. Kernel Hackers Manual July 2017 snd_pcm_stream_lock_irqsave 9 4.1.27 snd_pcm_stream_lock_irqsave Lock the PCM stream snd_pcm_stream_lock_irqsave substream flags substream PCM substream flags irq flags This locks the PCM stream like snd_pcm_stream_lock but with the local IRQ (only when nonatomic is false). In nonatomic case, this is identical as snd_pcm_stream_lock. Kernel Hackers Manual July 2017 snd_pcm_group_for_each_entry 9 4.1.27 snd_pcm_group_for_each_entry iterate over the linked substreams snd_pcm_group_for_each_entry s substream s the iterator substream the substream Iterate over the all linked substreams to the given substream. When substream isn't linked with any others, this gives returns substream itself once. Kernel Hackers Manual July 2017 snd_pcm_running 9 4.1.27 snd_pcm_running Check whether the substream is in a running state int snd_pcm_running struct snd_pcm_substream * substream substream substream to check Returns true if the given substream is in the state RUNNING, or in the state DRAINING for playback. Kernel Hackers Manual July 2017 bytes_to_samples 9 4.1.27 bytes_to_samples Unit conversion of the size from bytes to samples ssize_t bytes_to_samples struct snd_pcm_runtime * runtime ssize_t size runtime PCM runtime instance size size in bytes Kernel Hackers Manual July 2017 bytes_to_frames 9 4.1.27 bytes_to_frames Unit conversion of the size from bytes to frames snd_pcm_sframes_t bytes_to_frames struct snd_pcm_runtime * runtime ssize_t size runtime PCM runtime instance size size in bytes Kernel Hackers Manual July 2017 samples_to_bytes 9 4.1.27 samples_to_bytes Unit conversion of the size from samples to bytes ssize_t samples_to_bytes struct snd_pcm_runtime * runtime ssize_t size runtime PCM runtime instance size size in samples Kernel Hackers Manual July 2017 frames_to_bytes 9 4.1.27 frames_to_bytes Unit conversion of the size from frames to bytes ssize_t frames_to_bytes struct snd_pcm_runtime * runtime snd_pcm_sframes_t size runtime PCM runtime instance size size in frames Kernel Hackers Manual July 2017 frame_aligned 9 4.1.27 frame_aligned Check whether the byte size is aligned to frames int frame_aligned struct snd_pcm_runtime * runtime ssize_t bytes runtime PCM runtime instance bytes size in bytes Kernel Hackers Manual July 2017 snd_pcm_lib_buffer_bytes 9 4.1.27 snd_pcm_lib_buffer_bytes Get the buffer size of the current PCM in bytes size_t snd_pcm_lib_buffer_bytes struct snd_pcm_substream * substream substream PCM substream Kernel Hackers Manual July 2017 snd_pcm_lib_period_bytes 9 4.1.27 snd_pcm_lib_period_bytes Get the period size of the current PCM in bytes size_t snd_pcm_lib_period_bytes struct snd_pcm_substream * substream substream PCM substream Kernel Hackers Manual July 2017 snd_pcm_playback_avail 9 4.1.27 snd_pcm_playback_avail Get the available (writable) space for playback snd_pcm_uframes_t snd_pcm_playback_avail struct snd_pcm_runtime * runtime runtime PCM runtime instance Result is between 0 ... (boundary - 1) Kernel Hackers Manual July 2017 snd_pcm_capture_avail 9 4.1.27 snd_pcm_capture_avail Get the available (readable) space for capture snd_pcm_uframes_t snd_pcm_capture_avail struct snd_pcm_runtime * runtime runtime PCM runtime instance Result is between 0 ... (boundary - 1) Kernel Hackers Manual July 2017 snd_pcm_playback_hw_avail 9 4.1.27 snd_pcm_playback_hw_avail Get the queued space for playback snd_pcm_sframes_t snd_pcm_playback_hw_avail struct snd_pcm_runtime * runtime runtime PCM runtime instance Kernel Hackers Manual July 2017 snd_pcm_capture_hw_avail 9 4.1.27 snd_pcm_capture_hw_avail Get the free space for capture snd_pcm_sframes_t snd_pcm_capture_hw_avail struct snd_pcm_runtime * runtime runtime PCM runtime instance Kernel Hackers Manual July 2017 snd_pcm_playback_ready 9 4.1.27 snd_pcm_playback_ready check whether the playback buffer is available int snd_pcm_playback_ready struct snd_pcm_substream * substream substream the pcm substream instance Checks whether enough free space is available on the playback buffer. Non-zero if available, or zero if not. Kernel Hackers Manual July 2017 snd_pcm_capture_ready 9 4.1.27 snd_pcm_capture_ready check whether the capture buffer is available int snd_pcm_capture_ready struct snd_pcm_substream * substream substream the pcm substream instance Checks whether enough capture data is available on the capture buffer. Non-zero if available, or zero if not. Kernel Hackers Manual July 2017 snd_pcm_playback_data 9 4.1.27 snd_pcm_playback_data check whether any data exists on the playback buffer int snd_pcm_playback_data struct snd_pcm_substream * substream substream the pcm substream instance Checks whether any data exists on the playback buffer. Non-zero if any data exists, or zero if not. If stop_threshold is bigger or equal to boundary, then this function returns always non-zero. Kernel Hackers Manual July 2017 snd_pcm_playback_empty 9 4.1.27 snd_pcm_playback_empty check whether the playback buffer is empty int snd_pcm_playback_empty struct snd_pcm_substream * substream substream the pcm substream instance Checks whether the playback buffer is empty. Non-zero if empty, or zero if not. Kernel Hackers Manual July 2017 snd_pcm_capture_empty 9 4.1.27 snd_pcm_capture_empty check whether the capture buffer is empty int snd_pcm_capture_empty struct snd_pcm_substream * substream substream the pcm substream instance Checks whether the capture buffer is empty. Non-zero if empty, or zero if not. Kernel Hackers Manual July 2017 snd_pcm_trigger_done 9 4.1.27 snd_pcm_trigger_done Mark the master substream void snd_pcm_trigger_done struct snd_pcm_substream * substream struct snd_pcm_substream * master substream the pcm substream instance master the linked master substream When multiple substreams of the same card are linked and the hardware supports the single-shot operation, the driver calls this in the loop in snd_pcm_group_for_each_entry for marking the substream as done. Then most of trigger operations are performed only to the given master substream. The trigger_master mark is cleared at timestamp updates at the end of trigger operations. Kernel Hackers Manual July 2017 params_channels 9 4.1.27 params_channels Get the number of channels from the hw params unsigned int params_channels const struct snd_pcm_hw_params * p p hw params Kernel Hackers Manual July 2017 params_rate 9 4.1.27 params_rate Get the sample rate from the hw params unsigned int params_rate const struct snd_pcm_hw_params * p p hw params Kernel Hackers Manual July 2017 params_period_size 9 4.1.27 params_period_size Get the period size (in frames) from the hw params unsigned int params_period_size const struct snd_pcm_hw_params * p p hw params Kernel Hackers Manual July 2017 params_periods 9 4.1.27 params_periods Get the number of periods from the hw params unsigned int params_periods const struct snd_pcm_hw_params * p p hw params Kernel Hackers Manual July 2017 params_buffer_size 9 4.1.27 params_buffer_size Get the buffer size (in frames) from the hw params unsigned int params_buffer_size const struct snd_pcm_hw_params * p p hw params Kernel Hackers Manual July 2017 params_buffer_bytes 9 4.1.27 params_buffer_bytes Get the buffer size (in bytes) from the hw params unsigned int params_buffer_bytes const struct snd_pcm_hw_params * p p hw params Kernel Hackers Manual July 2017 snd_pcm_format_cpu_endian 9 4.1.27 snd_pcm_format_cpu_endian Check the PCM format is CPU-endian int snd_pcm_format_cpu_endian snd_pcm_format_t format format the format to check 1 if the given PCM format is CPU-endian, 0 if opposite, or a negative error code if endian not specified. Kernel Hackers Manual July 2017 snd_pcm_set_runtime_buffer 9 4.1.27 snd_pcm_set_runtime_buffer Set the PCM runtime buffer void snd_pcm_set_runtime_buffer struct snd_pcm_substream * substream struct snd_dma_buffer * bufp substream PCM substream to set bufp the buffer information, NULL to clear Copy the buffer information to runtime->dma_buffer when bufp is non-NULL. Otherwise it clears the current buffer information. Kernel Hackers Manual July 2017 snd_pcm_gettime 9 4.1.27 snd_pcm_gettime Fill the timespec depending on the timestamp mode void snd_pcm_gettime struct snd_pcm_runtime * runtime struct timespec * tv runtime PCM runtime instance tv timespec to fill Kernel Hackers Manual July 2017 snd_pcm_lib_alloc_vmalloc_buffer 9 4.1.27 snd_pcm_lib_alloc_vmalloc_buffer allocate virtual DMA buffer int snd_pcm_lib_alloc_vmalloc_buffer struct snd_pcm_substream * substream size_t size substream the substream to allocate the buffer to size the requested buffer size, in bytes Allocates the PCM substream buffer using vmalloc, i.e., the memory is contiguous in kernel virtual space, but not in physical memory. Use this if the buffer is accessed by kernel code but not by device DMA. 1 if the buffer was changed, 0 if not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_lib_alloc_vmalloc_32_buffer 9 4.1.27 snd_pcm_lib_alloc_vmalloc_32_buffer allocate 32-bit-addressable buffer int snd_pcm_lib_alloc_vmalloc_32_buffer struct snd_pcm_substream * substream size_t size substream the substream to allocate the buffer to size the requested buffer size, in bytes This function works like snd_pcm_lib_alloc_vmalloc_buffer, but uses vmalloc_32, i.e., the pages are allocated from 32-bit-addressable memory. 1 if the buffer was changed, 0 if not changed, or a negative error code. Kernel Hackers Manual July 2017 snd_pcm_sgbuf_get_addr 9 4.1.27 snd_pcm_sgbuf_get_addr Get the DMA address at the corresponding offset dma_addr_t snd_pcm_sgbuf_get_addr struct snd_pcm_substream * substream unsigned int ofs substream PCM substream ofs byte offset Kernel Hackers Manual July 2017 snd_pcm_sgbuf_get_ptr 9 4.1.27 snd_pcm_sgbuf_get_ptr Get the virtual address at the corresponding offset void * snd_pcm_sgbuf_get_ptr struct snd_pcm_substream * substream unsigned int ofs substream PCM substream ofs byte offset Kernel Hackers Manual July 2017 snd_pcm_sgbuf_get_chunk_size 9 4.1.27 snd_pcm_sgbuf_get_chunk_size Compute the max size that fits within the contig. page from the given size unsigned int snd_pcm_sgbuf_get_chunk_size struct snd_pcm_substream * substream unsigned int ofs unsigned int size substream PCM substream ofs byte offset size byte size to examine Kernel Hackers Manual July 2017 snd_pcm_mmap_data_open 9 4.1.27 snd_pcm_mmap_data_open increase the mmap counter void snd_pcm_mmap_data_open struct vm_area_struct * area area VMA PCM mmap callback should handle this counter properly Kernel Hackers Manual July 2017 snd_pcm_mmap_data_close 9 4.1.27 snd_pcm_mmap_data_close decrease the mmap counter void snd_pcm_mmap_data_close struct vm_area_struct * area area VMA PCM mmap callback should handle this counter properly Kernel Hackers Manual July 2017 snd_pcm_limit_isa_dma_size 9 4.1.27 snd_pcm_limit_isa_dma_size Get the max size fitting with ISA DMA transfer void snd_pcm_limit_isa_dma_size int dma size_t * max dma DMA number max pointer to store the max size Kernel Hackers Manual July 2017 snd_pcm_stream_str 9 4.1.27 snd_pcm_stream_str Get a string naming the direction of a stream const char * snd_pcm_stream_str struct snd_pcm_substream * substream substream the pcm substream instance A string naming the direction of the stream. Kernel Hackers Manual July 2017 snd_pcm_chmap_substream 9 4.1.27 snd_pcm_chmap_substream get the PCM substream assigned to the given chmap info struct snd_pcm_substream * snd_pcm_chmap_substream struct snd_pcm_chmap * info unsigned int idx info chmap information idx the substream number index Kernel Hackers Manual July 2017 pcm_format_to_bits 9 4.1.27 pcm_format_to_bits Strong-typed conversion of pcm_format to bitwise u64 pcm_format_to_bits snd_pcm_format_t pcm_format pcm_format PCM format Kernel Hackers Manual July 2017 snd_pcm_format_signed 9 4.1.27 snd_pcm_format_signed Check the PCM format is signed linear int snd_pcm_format_signed snd_pcm_format_t format format the format to check 1 if the given PCM format is signed linear, 0 if unsigned linear, and a negative error code for non-linear formats. Kernel Hackers Manual July 2017 snd_pcm_format_unsigned 9 4.1.27 snd_pcm_format_unsigned Check the PCM format is unsigned linear int snd_pcm_format_unsigned snd_pcm_format_t format format the format to check 1 if the given PCM format is unsigned linear, 0 if signed linear, and a negative error code for non-linear formats. Kernel Hackers Manual July 2017 snd_pcm_format_linear 9 4.1.27 snd_pcm_format_linear Check the PCM format is linear int snd_pcm_format_linear snd_pcm_format_t format format the format to check 1 if the given PCM format is linear, 0 if not. Kernel Hackers Manual July 2017 snd_pcm_format_little_endian 9 4.1.27 snd_pcm_format_little_endian Check the PCM format is little-endian int snd_pcm_format_little_endian snd_pcm_format_t format format the format to check 1 if the given PCM format is little-endian, 0 if big-endian, or a negative error code if endian not specified. Kernel Hackers Manual July 2017 snd_pcm_format_big_endian 9 4.1.27 snd_pcm_format_big_endian Check the PCM format is big-endian int snd_pcm_format_big_endian snd_pcm_format_t format format the format to check 1 if the given PCM format is big-endian, 0 if little-endian, or a negative error code if endian not specified. Kernel Hackers Manual July 2017 snd_pcm_format_width 9 4.1.27 snd_pcm_format_width return the bit-width of the format int snd_pcm_format_width snd_pcm_format_t format format the format to check The bit-width of the format, or a negative error code if unknown format. Kernel Hackers Manual July 2017 snd_pcm_format_physical_width 9 4.1.27 snd_pcm_format_physical_width return the physical bit-width of the format int snd_pcm_format_physical_width snd_pcm_format_t format format the format to check The physical bit-width of the format, or a negative error code if unknown format. Kernel Hackers Manual July 2017 snd_pcm_format_size 9 4.1.27 snd_pcm_format_size return the byte size of samples on the given format ssize_t snd_pcm_format_size snd_pcm_format_t format size_t samples format the format to check samples sampling rate The byte size of the given samples for the format, or a negative error code if unknown format. Kernel Hackers Manual July 2017 snd_pcm_format_silence_64 9 4.1.27 snd_pcm_format_silence_64 return the silent data in 8 bytes array const unsigned char * snd_pcm_format_silence_64 snd_pcm_format_t format format the format to check The format pattern to fill or NULL if error. Kernel Hackers Manual July 2017 snd_pcm_format_set_silence 9 4.1.27 snd_pcm_format_set_silence set the silence data on the buffer int snd_pcm_format_set_silence snd_pcm_format_t format void * data unsigned int samples format the PCM format data the buffer pointer samples the number of samples to set silence Sets the silence data on the buffer for the given samples. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_limit_hw_rates 9 4.1.27 snd_pcm_limit_hw_rates determine rate_min/rate_max fields int snd_pcm_limit_hw_rates struct snd_pcm_runtime * runtime runtime the runtime instance Determines the rate_min and rate_max fields from the rates bits of the given runtime->hw. Zero if successful. Kernel Hackers Manual July 2017 snd_pcm_rate_to_rate_bit 9 4.1.27 snd_pcm_rate_to_rate_bit converts sample rate to SNDRV_PCM_RATE_xxx bit unsigned int snd_pcm_rate_to_rate_bit unsigned int rate rate the sample rate to convert The SNDRV_PCM_RATE_xxx flag that corresponds to the given rate, or SNDRV_PCM_RATE_KNOT for an unknown rate. Kernel Hackers Manual July 2017 snd_pcm_rate_bit_to_rate 9 4.1.27 snd_pcm_rate_bit_to_rate converts SNDRV_PCM_RATE_xxx bit to sample rate unsigned int snd_pcm_rate_bit_to_rate unsigned int rate_bit rate_bit the rate bit to convert The sample rate that corresponds to the given SNDRV_PCM_RATE_xxx flag or 0 for an unknown rate bit. Kernel Hackers Manual July 2017 snd_pcm_rate_mask_intersect 9 4.1.27 snd_pcm_rate_mask_intersect computes the intersection between two rate masks unsigned int snd_pcm_rate_mask_intersect unsigned int rates_a unsigned int rates_b rates_a The first rate mask rates_b The second rate mask This function computes the rates that are supported by both rate masks passed to the function. It will take care of the special handling of SNDRV_PCM_RATE_CONTINUOUS and SNDRV_PCM_RATE_KNOT. A rate mask containing the rates that are supported by both rates_a and rates_b. Kernel Hackers Manual July 2017 snd_pcm_lib_preallocate_free_for_all 9 4.1.27 snd_pcm_lib_preallocate_free_for_all release all pre-allocated buffers on the pcm int snd_pcm_lib_preallocate_free_for_all struct snd_pcm * pcm pcm the pcm instance Releases all the pre-allocated buffers on the given pcm. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_preallocate_pages 9 4.1.27 snd_pcm_lib_preallocate_pages pre-allocation for the given DMA type int snd_pcm_lib_preallocate_pages struct snd_pcm_substream * substream int type struct device * data size_t size size_t max substream the pcm substream instance type DMA type (SNDRV_DMA_TYPE_*) data DMA type dependent data size the requested pre-allocation size in bytes max the max. allowed pre-allocation size Do pre-allocation for the given DMA buffer type. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_preallocate_pages_for_all 9 4.1.27 snd_pcm_lib_preallocate_pages_for_all pre-allocation for continuous memory type (all substreams) int snd_pcm_lib_preallocate_pages_for_all struct snd_pcm * pcm int type void * data size_t size size_t max pcm the pcm instance type DMA type (SNDRV_DMA_TYPE_*) data DMA type dependent data size the requested pre-allocation size in bytes max the max. allowed pre-allocation size Do pre-allocation to all substreams of the given pcm for the specified DMA type. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_sgbuf_ops_page 9 4.1.27 snd_pcm_sgbuf_ops_page get the page struct at the given offset struct page * snd_pcm_sgbuf_ops_page struct snd_pcm_substream * substream unsigned long offset substream the pcm substream instance offset the buffer offset Used as the page callback of PCM ops. The page struct at the given buffer offset. NULL on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_malloc_pages 9 4.1.27 snd_pcm_lib_malloc_pages allocate the DMA buffer int snd_pcm_lib_malloc_pages struct snd_pcm_substream * substream size_t size substream the substream to allocate the DMA buffer to size the requested buffer size in bytes Allocates the DMA buffer on the BUS type given earlier to snd_pcm_lib_preallocate_xxx_pages. 1 if the buffer is changed, 0 if not changed, or a negative code on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_free_pages 9 4.1.27 snd_pcm_lib_free_pages release the allocated DMA buffer. int snd_pcm_lib_free_pages struct snd_pcm_substream * substream substream the substream to release the DMA buffer Releases the DMA buffer allocated via snd_pcm_lib_malloc_pages. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_free_vmalloc_buffer 9 4.1.27 snd_pcm_lib_free_vmalloc_buffer free vmalloc buffer int snd_pcm_lib_free_vmalloc_buffer struct snd_pcm_substream * substream substream the substream with a buffer allocated by snd_pcm_lib_alloc_vmalloc_buffer Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_pcm_lib_get_vmalloc_page 9 4.1.27 snd_pcm_lib_get_vmalloc_page map vmalloc buffer offset to page struct struct page * snd_pcm_lib_get_vmalloc_page struct snd_pcm_substream * substream unsigned long offset substream the substream with a buffer allocated by snd_pcm_lib_alloc_vmalloc_buffer offset offset in the buffer This function is to be used as the page callback in the PCM ops. The page struct, or NULL on failure. Kernel Hackers Manual July 2017 snd_hwparams_to_dma_slave_config 9 4.1.27 snd_hwparams_to_dma_slave_config Convert hw_params to dma_slave_config int snd_hwparams_to_dma_slave_config const struct snd_pcm_substream * substream const struct snd_pcm_hw_params * params struct dma_slave_config * slave_config substream PCM substream params hw_params slave_config DMA slave config This function can be used to initialize a dma_slave_config from a substream and hw_params in a dmaengine based PCM driver implementation. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_set_config_from_dai_data 9 4.1.27 snd_dmaengine_pcm_set_config_from_dai_data Initializes a dma slave config using DAI DMA data. void snd_dmaengine_pcm_set_config_from_dai_data const struct snd_pcm_substream * substream const struct snd_dmaengine_dai_dma_data * dma_data struct dma_slave_config * slave_config substream PCM substream dma_data DAI DMA data slave_config DMA slave configuration Initializes the {dst,src}_addr, {dst,src}_maxburst, {dst,src}_addr_width and slave_id fields of the DMA slave config from the same fields of the DAI DMA data struct. The src and dst fields will be initialized depending on the direction of the substream. If the substream is a playback stream the dst fields will be initialized, if it is a capture stream the src fields will be initialized. The {dst,src}_addr_width field will only be initialized if the addr_width field of the DAI DMA data struct is not equal to DMA_SLAVE_BUSWIDTH_UNDEFINED. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_trigger 9 4.1.27 snd_dmaengine_pcm_trigger dmaengine based PCM trigger implementation int snd_dmaengine_pcm_trigger struct snd_pcm_substream * substream int cmd substream PCM substream cmd Trigger command Returns 0 on success, a negative error code otherwise. This function can be used as the PCM trigger callback for dmaengine based PCM driver implementations. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_pointer_no_residue 9 4.1.27 snd_dmaengine_pcm_pointer_no_residue dmaengine based PCM pointer implementation snd_pcm_uframes_t snd_dmaengine_pcm_pointer_no_residue struct snd_pcm_substream * substream substream PCM substream This function is deprecated and should not be used by new drivers, as its results may be unreliable. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_pointer 9 4.1.27 snd_dmaengine_pcm_pointer dmaengine based PCM pointer implementation snd_pcm_uframes_t snd_dmaengine_pcm_pointer struct snd_pcm_substream * substream substream PCM substream This function can be used as the PCM pointer callback for dmaengine based PCM driver implementations. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_request_channel 9 4.1.27 snd_dmaengine_pcm_request_channel Request channel for the dmaengine PCM struct dma_chan * snd_dmaengine_pcm_request_channel dma_filter_fn filter_fn void * filter_data filter_fn Filter function used to request the DMA channel filter_data Data passed to the DMA filter function Returns NULL or the requested DMA channel. This function request a DMA channel for usage with dmaengine PCM. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_open 9 4.1.27 snd_dmaengine_pcm_open Open a dmaengine based PCM substream int snd_dmaengine_pcm_open struct snd_pcm_substream * substream struct dma_chan * chan substream PCM substream chan DMA channel to use for data transfers Returns 0 on success, a negative error code otherwise. The function should usually be called from the pcm open callback. Note that this function will use private_data field of the substream's runtime. So it is not available to your pcm driver implementation. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_open_request_chan 9 4.1.27 snd_dmaengine_pcm_open_request_chan Open a dmaengine based PCM substream and request channel int snd_dmaengine_pcm_open_request_chan struct snd_pcm_substream * substream dma_filter_fn filter_fn void * filter_data substream PCM substream filter_fn Filter function used to request the DMA channel filter_data Data passed to the DMA filter function Returns 0 on success, a negative error code otherwise. This function will request a DMA channel using the passed filter function and data. The function should usually be called from the pcm open callback. Note that this function will use private_data field of the substream's runtime. So it is not available to your pcm driver implementation. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_close 9 4.1.27 snd_dmaengine_pcm_close Close a dmaengine based PCM substream int snd_dmaengine_pcm_close struct snd_pcm_substream * substream substream PCM substream Kernel Hackers Manual July 2017 snd_dmaengine_pcm_close_release_chan 9 4.1.27 snd_dmaengine_pcm_close_release_chan Close a dmaengine based PCM substream and release channel int snd_dmaengine_pcm_close_release_chan struct snd_pcm_substream * substream substream PCM substream Releases the DMA channel associated with the PCM substream. Kernel Hackers Manual July 2017 snd_pcm_substream_to_dma_direction 9 4.1.27 snd_pcm_substream_to_dma_direction Get dma_transfer_direction for a PCM substream enum dma_transfer_direction snd_pcm_substream_to_dma_direction const struct snd_pcm_substream * substream substream PCM substream Kernel Hackers Manual July 2017 struct snd_dmaengine_dai_dma_data 9 4.1.27 struct snd_dmaengine_dai_dma_data DAI DMA configuration data struct snd_dmaengine_dai_dma_data { dma_addr_t addr; enum dma_slave_buswidth addr_width; u32 maxburst; unsigned int slave_id; void * filter_data; const char * chan_name; unsigned int fifo_size; }; addr Address of the DAI data source or destination register. addr_width Width of the DAI data source or destination register. maxburst Maximum number of words(note: words, as in units of the src_addr_width member, not bytes) that can be send to or received from the DAI in one burst. slave_id Slave requester id for the DMA channel. filter_data Custom DMA channel filter data, this will usually be used when requesting the DMA channel. chan_name Custom channel name to use when requesting DMA channel. fifo_size FIFO size of the DAI controller in bytes Kernel Hackers Manual July 2017 struct snd_dmaengine_pcm_config 9 4.1.27 struct snd_dmaengine_pcm_config Configuration data for dmaengine based PCM struct snd_dmaengine_pcm_config { int (* prepare_slave_config) (struct snd_pcm_substream *substream,struct snd_pcm_hw_params *params,struct dma_slave_config *slave_config); struct dma_chan *(* compat_request_channel) (struct snd_soc_pcm_runtime *rtd,struct snd_pcm_substream *substream); dma_filter_fn compat_filter_fn; struct device * dma_dev; const char * chan_names[SNDRV_PCM_STREAM_LAST + 1]; const struct snd_pcm_hardware * pcm_hardware; unsigned int prealloc_buffer_size; }; prepare_slave_config Callback used to fill in the DMA slave_config for a PCM substream. Will be called from the PCM drivers hwparams callback. compat_request_channel Callback to request a DMA channel for platforms which do not use devicetree. compat_filter_fn Will be used as the filter function when requesting a channel for platforms which do not use devicetree. The filter parameter will be the DAI's DMA data. dma_dev If set, request DMA channel on this device rather than the DAI device. chan_names[SNDRV_PCM_STREAM_LAST + 1] If set, these custom DMA channel names will be requested at registration time. pcm_hardware snd_pcm_hardware struct to be used for the PCM. prealloc_buffer_size Size of the preallocated audio buffer. If both compat_request_channel and compat_filter_fn are set compat_request_channel will be used to request the channel and compat_filter_fn will be ignored. Otherwise the channel will be requested using dma_request_channel with compat_filter_fn as the filter function. Kernel Hackers Manual July 2017 snd_ctl_notify 9 4.1.27 snd_ctl_notify Send notification to user-space for a control change void snd_ctl_notify struct snd_card * card unsigned int mask struct snd_ctl_elem_id * id card the card to send notification mask the event mask, SNDRV_CTL_EVENT_* id the ctl element id to send notification This function adds an event record with the given id and mask, appends to the list and wakes up the user-space for notification. This can be called in the atomic context. Kernel Hackers Manual July 2017 snd_ctl_new1 9 4.1.27 snd_ctl_new1 create a control instance from the template struct snd_kcontrol * snd_ctl_new1 const struct snd_kcontrol_new * ncontrol void * private_data ncontrol the initialization record private_data the private data to set Allocates a new struct snd_kcontrol instance and initialize from the given template. When the access field of ncontrol is 0, it's assumed as READWRITE access. When the count field is 0, it's assumes as one. The pointer of the newly generated instance, or NULL on failure. Kernel Hackers Manual July 2017 snd_ctl_free_one 9 4.1.27 snd_ctl_free_one release the control instance void snd_ctl_free_one struct snd_kcontrol * kcontrol kcontrol the control instance Releases the control instance created via snd_ctl_new or snd_ctl_new1. Don't call this after the control was added to the card. Kernel Hackers Manual July 2017 snd_ctl_add 9 4.1.27 snd_ctl_add add the control instance to the card int snd_ctl_add struct snd_card * card struct snd_kcontrol * kcontrol card the card instance kcontrol the control instance to add Adds the control instance created via snd_ctl_new or snd_ctl_new1 to the given card. Assigns also an unique numid used for fast search. It frees automatically the control which cannot be added. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_replace 9 4.1.27 snd_ctl_replace replace the control instance of the card int snd_ctl_replace struct snd_card * card struct snd_kcontrol * kcontrol bool add_on_replace card the card instance kcontrol the control instance to replace add_on_replace add the control if not already added Replaces the given control. If the given control does not exist and the add_on_replace flag is set, the control is added. If the control exists, it is destroyed first. It frees automatically the control which cannot be added or replaced. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_remove 9 4.1.27 snd_ctl_remove remove the control from the card and release it int snd_ctl_remove struct snd_card * card struct snd_kcontrol * kcontrol card the card instance kcontrol the control instance to remove Removes the control from the card and then releases the instance. You don't need to call snd_ctl_free_one. You must be in the write lock - down_write(card->controls_rwsem). 0 if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_remove_id 9 4.1.27 snd_ctl_remove_id remove the control of the given id and release it int snd_ctl_remove_id struct snd_card * card struct snd_ctl_elem_id * id card the card instance id the control id to remove Finds the control instance with the given id, removes it from the card list and releases it. 0 if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_activate_id 9 4.1.27 snd_ctl_activate_id activate/inactivate the control of the given id int snd_ctl_activate_id struct snd_card * card struct snd_ctl_elem_id * id int active card the card instance id the control id to activate/inactivate active non-zero to activate Finds the control instance with the given id, and activate or inactivate the control together with notification, if changed. The given ID data is filled with full information. 0 if unchanged, 1 if changed, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_rename_id 9 4.1.27 snd_ctl_rename_id replace the id of a control on the card int snd_ctl_rename_id struct snd_card * card struct snd_ctl_elem_id * src_id struct snd_ctl_elem_id * dst_id card the card instance src_id the old id dst_id the new id Finds the control with the old id from the card, and replaces the id with the new one. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_find_numid 9 4.1.27 snd_ctl_find_numid find the control instance with the given number-id struct snd_kcontrol * snd_ctl_find_numid struct snd_card * card unsigned int numid card the card instance numid the number-id to search Finds the control instance with the given number-id from the card. The caller must down card->controls_rwsem before calling this function (if the race condition can happen). The pointer of the instance if found, or NULL if not. Kernel Hackers Manual July 2017 snd_ctl_find_id 9 4.1.27 snd_ctl_find_id find the control instance with the given id struct snd_kcontrol * snd_ctl_find_id struct snd_card * card struct snd_ctl_elem_id * id card the card instance id the id to search Finds the control instance with the given id from the card. The caller must down card->controls_rwsem before calling this function (if the race condition can happen). The pointer of the instance if found, or NULL if not. Kernel Hackers Manual July 2017 snd_ctl_register_ioctl 9 4.1.27 snd_ctl_register_ioctl register the device-specific control-ioctls int snd_ctl_register_ioctl snd_kctl_ioctl_func_t fcn fcn ioctl callback function called from each device manager like pcm.c, hwdep.c, etc. Kernel Hackers Manual July 2017 snd_ctl_register_ioctl_compat 9 4.1.27 snd_ctl_register_ioctl_compat register the device-specific 32bit compat control-ioctls int snd_ctl_register_ioctl_compat snd_kctl_ioctl_func_t fcn fcn ioctl callback function Kernel Hackers Manual July 2017 snd_ctl_unregister_ioctl 9 4.1.27 snd_ctl_unregister_ioctl de-register the device-specific control-ioctls int snd_ctl_unregister_ioctl snd_kctl_ioctl_func_t fcn fcn ioctl callback function to unregister Kernel Hackers Manual July 2017 snd_ctl_unregister_ioctl_compat 9 4.1.27 snd_ctl_unregister_ioctl_compat de-register the device-specific compat 32bit control-ioctls int snd_ctl_unregister_ioctl_compat snd_kctl_ioctl_func_t fcn fcn ioctl callback function to unregister Kernel Hackers Manual July 2017 snd_ctl_boolean_mono_info 9 4.1.27 snd_ctl_boolean_mono_info Helper function for a standard boolean info callback with a mono channel int snd_ctl_boolean_mono_info struct snd_kcontrol * kcontrol struct snd_ctl_elem_info * uinfo kcontrol the kcontrol instance uinfo info to store This is a function that can be used as info callback for a standard boolean control with a single mono channel. Kernel Hackers Manual July 2017 snd_ctl_boolean_stereo_info 9 4.1.27 snd_ctl_boolean_stereo_info Helper function for a standard boolean info callback with stereo two channels int snd_ctl_boolean_stereo_info struct snd_kcontrol * kcontrol struct snd_ctl_elem_info * uinfo kcontrol the kcontrol instance uinfo info to store This is a function that can be used as info callback for a standard boolean control with stereo two channels. Kernel Hackers Manual July 2017 snd_ctl_enum_info 9 4.1.27 snd_ctl_enum_info fills the info structure for an enumerated control int snd_ctl_enum_info struct snd_ctl_elem_info * info unsigned int channels unsigned int items const char *const names[] info the structure to be filled channels the number of the control's channels; often one items the number of control values; also the size of names names[] an array containing the names of all control values Sets all required fields in info to their appropriate values. If the control's accessibility is not the default (readable and writable), the caller has to fill info->access. Zero. Kernel Hackers Manual July 2017 snd_ac97_write 9 4.1.27 snd_ac97_write write a value on the given register void snd_ac97_write struct snd_ac97 * ac97 unsigned short reg unsigned short value ac97 the ac97 instance reg the register to change value the value to set Writes a value on the given register. This will invoke the write callback directly after the register check. This function doesn't change the register cache unlike #snd_ca97_write_cache, so use this only when you don't want to reflect the change to the suspend/resume state. Kernel Hackers Manual July 2017 snd_ac97_read 9 4.1.27 snd_ac97_read read a value from the given register unsigned short snd_ac97_read struct snd_ac97 * ac97 unsigned short reg ac97 the ac97 instance reg the register to read Reads a value from the given register. This will invoke the read callback directly after the register check. The read value. Kernel Hackers Manual July 2017 snd_ac97_write_cache 9 4.1.27 snd_ac97_write_cache write a value on the given register and update the cache void snd_ac97_write_cache struct snd_ac97 * ac97 unsigned short reg unsigned short value ac97 the ac97 instance reg the register to change value the value to set Writes a value on the given register and updates the register cache. The cached values are used for the cached-read and the suspend/resume. Kernel Hackers Manual July 2017 snd_ac97_update 9 4.1.27 snd_ac97_update update the value on the given register int snd_ac97_update struct snd_ac97 * ac97 unsigned short reg unsigned short value ac97 the ac97 instance reg the register to change value the value to set Compares the value with the register cache and updates the value only when the value is changed. 1 if the value is changed, 0 if no change, or a negative code on failure. Kernel Hackers Manual July 2017 snd_ac97_update_bits 9 4.1.27 snd_ac97_update_bits update the bits on the given register int snd_ac97_update_bits struct snd_ac97 * ac97 unsigned short reg unsigned short mask unsigned short value ac97 the ac97 instance reg the register to change mask the bit-mask to change value the value to set Updates the masked-bits on the given register only when the value is changed. 1 if the bits are changed, 0 if no change, or a negative code on failure. Kernel Hackers Manual July 2017 snd_ac97_get_short_name 9 4.1.27 snd_ac97_get_short_name retrieve codec name const char * snd_ac97_get_short_name struct snd_ac97 * ac97 ac97 the codec instance The short identifying name of the codec. Kernel Hackers Manual July 2017 snd_ac97_bus 9 4.1.27 snd_ac97_bus create an AC97 bus component int snd_ac97_bus struct snd_card * card int num struct snd_ac97_bus_ops * ops void * private_data struct snd_ac97_bus ** rbus card the card instance num the bus number ops the bus callbacks table private_data private data pointer for the new instance rbus the pointer to store the new AC97 bus instance. Creates an AC97 bus component. An struct snd_ac97_bus instance is newly allocated and initialized. The ops table must include valid callbacks (at least read and write). The other callbacks, wait and reset, are not mandatory. The clock is set to 48000. If another clock is needed, set (*rbus)->clock manually. The AC97 bus instance is registered as a low-level device, so you don't have to release it manually. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ac97_mixer 9 4.1.27 snd_ac97_mixer create an Codec97 component int snd_ac97_mixer struct snd_ac97_bus * bus struct snd_ac97_template * template struct snd_ac97 ** rac97 bus the AC97 bus which codec is attached to template the template of ac97, including index, callbacks and the private data. rac97 the pointer to store the new ac97 instance. Creates an Codec97 component. An struct snd_ac97 instance is newly allocated and initialized from the template. The codec is then initialized by the standard procedure. The template must include the codec number (num) and address (addr), and the private data (private_data). The ac97 instance is registered as a low-level device, so you don't have to release it manually. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ac97_update_power 9 4.1.27 snd_ac97_update_power update the powerdown register int snd_ac97_update_power struct snd_ac97 * ac97 int reg int powerup ac97 the codec instance reg the rate register, e.g. AC97_PCM_FRONT_DAC_RATE powerup non-zero when power up the part Update the AC97 powerdown register bits of the given part. Zero. Kernel Hackers Manual July 2017 snd_ac97_suspend 9 4.1.27 snd_ac97_suspend General suspend function for AC97 codec void snd_ac97_suspend struct snd_ac97 * ac97 ac97 the ac97 instance Suspends the codec, power down the chip. Kernel Hackers Manual July 2017 snd_ac97_resume 9 4.1.27 snd_ac97_resume General resume function for AC97 codec void snd_ac97_resume struct snd_ac97 * ac97 ac97 the ac97 instance Do the standard resume procedure, power up and restoring the old register values. Kernel Hackers Manual July 2017 snd_ac97_tune_hardware 9 4.1.27 snd_ac97_tune_hardware tune up the hardware int snd_ac97_tune_hardware struct snd_ac97 * ac97 const struct ac97_quirk * quirk const char * override ac97 the ac97 instance quirk quirk list override explicit quirk value (overrides the list if non-NULL) Do some workaround for each pci device, such as renaming of the headphone (true line-out) control as Master. The quirk-list must be terminated with a zero-filled entry. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ac97_set_rate 9 4.1.27 snd_ac97_set_rate change the rate of the given input/output. int snd_ac97_set_rate struct snd_ac97 * ac97 int reg unsigned int rate ac97 the ac97 instance reg the register to change rate the sample rate to set Changes the rate of the given input/output on the codec. If the codec doesn't support VAR, the rate must be 48000 (except for SPDIF). The valid registers are AC97_PMC_MIC_ADC_RATE, AC97_PCM_FRONT_DAC_RATE, AC97_PCM_LR_ADC_RATE. AC97_PCM_SURR_DAC_RATE and AC97_PCM_LFE_DAC_RATE are accepted if the codec supports them. AC97_SPDIF is accepted as a pseudo register to modify the SPDIF status bits. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ac97_pcm_assign 9 4.1.27 snd_ac97_pcm_assign assign AC97 slots to given PCM streams int snd_ac97_pcm_assign struct snd_ac97_bus * bus unsigned short pcms_count const struct ac97_pcm * pcms bus the ac97 bus instance pcms_count count of PCMs to be assigned pcms PCMs to be assigned It assigns available AC97 slots for given PCMs. If none or only some slots are available, pcm->xxx.slots and pcm->xxx.rslots[] members are reduced and might be zero. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ac97_pcm_open 9 4.1.27 snd_ac97_pcm_open opens the given AC97 pcm int snd_ac97_pcm_open struct ac97_pcm * pcm unsigned int rate enum ac97_pcm_cfg cfg unsigned short slots pcm the ac97 pcm instance rate rate in Hz, if codec does not support VRA, this value must be 48000Hz cfg output stream characteristics slots a subset of allocated slots (snd_ac97_pcm_assign) for this pcm It locks the specified slots and sets the given rate to AC97 registers. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ac97_pcm_close 9 4.1.27 snd_ac97_pcm_close closes the given AC97 pcm int snd_ac97_pcm_close struct ac97_pcm * pcm pcm the ac97 pcm instance It frees the locked AC97 slots. Zero. Kernel Hackers Manual July 2017 snd_ac97_pcm_double_rate_rules 9 4.1.27 snd_ac97_pcm_double_rate_rules set double rate constraints int snd_ac97_pcm_double_rate_rules struct snd_pcm_runtime * runtime runtime the runtime of the ac97 front playback pcm Installs the hardware constraint rules to prevent using double rates and more than two channels at the same time. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_ctl_make_virtual_master 9 4.1.27 snd_ctl_make_virtual_master Create a virtual master control struct snd_kcontrol * snd_ctl_make_virtual_master char * name const unsigned int * tlv name name string of the control element to create tlv optional TLV int array for dB information Creates a virtual master control with the given name string. After creating a vmaster element, you can add the slave controls via snd_ctl_add_slave or snd_ctl_add_slave_uncached. The optional argument tlv can be used to specify the TLV information for dB scale of the master control. It should be a single element with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB. The created control element, or NULL for errors (ENOMEM). Kernel Hackers Manual July 2017 snd_ctl_add_vmaster_hook 9 4.1.27 snd_ctl_add_vmaster_hook Add a hook to a vmaster control int snd_ctl_add_vmaster_hook struct snd_kcontrol * kcontrol void (*hook) void *private_data, int void * private_data kcontrol vmaster kctl element hook the hook function private_data the private_data pointer to be saved Adds the given hook to the vmaster control element so that it's called at each time when the value is changed. Zero. Kernel Hackers Manual July 2017 snd_ctl_sync_vmaster 9 4.1.27 snd_ctl_sync_vmaster Sync the vmaster slaves and hook void snd_ctl_sync_vmaster struct snd_kcontrol * kcontrol bool hook_only kcontrol vmaster kctl element hook_only sync only the hook Forcibly call the put callback of each slave and call the hook function to synchronize with the current value of the given vmaster element. NOP when NULL is passed to kcontrol. Kernel Hackers Manual July 2017 snd_ctl_add_slave 9 4.1.27 snd_ctl_add_slave Add a virtual slave control int snd_ctl_add_slave struct snd_kcontrol * master struct snd_kcontrol * slave master vmaster element slave slave element to add Add a virtual slave control to the given master element created via snd_ctl_create_virtual_master beforehand. All slaves must be the same type (returning the same information via info callback). The function doesn't check it, so it's your responsibility. Also, some additional limitations: at most two channels, logarithmic volume control (dB level) thus no linear volume, master can only attenuate the volume without gain Zero if successful or a negative error code. Kernel Hackers Manual July 2017 snd_ctl_add_slave_uncached 9 4.1.27 snd_ctl_add_slave_uncached Add a virtual slave control int snd_ctl_add_slave_uncached struct snd_kcontrol * master struct snd_kcontrol * slave master vmaster element slave slave element to add Add a virtual slave control to the given master. Unlike snd_ctl_add_slave, the element added via this function is supposed to have volatile values, and get callback is called at each time queried from the master. When the control peeks the hardware values directly and the value can be changed by other means than the put callback of the element, this function should be used to keep the value always up-to-date. Zero if successful or a negative error code. Kernel Hackers Manual July 2017 snd_rawmidi_receive 9 4.1.27 snd_rawmidi_receive receive the input data from the device int snd_rawmidi_receive struct snd_rawmidi_substream * substream const unsigned char * buffer int count substream the rawmidi substream buffer the buffer pointer count the data size to read Reads the data from the internal buffer. The size of read data, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_rawmidi_transmit_empty 9 4.1.27 snd_rawmidi_transmit_empty check whether the output buffer is empty int snd_rawmidi_transmit_empty struct snd_rawmidi_substream * substream substream the rawmidi substream 1 if the internal output buffer is empty, 0 if not. Kernel Hackers Manual July 2017 __snd_rawmidi_transmit_peek 9 4.1.27 __snd_rawmidi_transmit_peek copy data from the internal buffer int __snd_rawmidi_transmit_peek struct snd_rawmidi_substream * substream unsigned char * buffer int count substream the rawmidi substream buffer the buffer pointer count data size to transfer This is a variant of snd_rawmidi_transmit_peek without spinlock. Kernel Hackers Manual July 2017 snd_rawmidi_transmit_peek 9 4.1.27 snd_rawmidi_transmit_peek copy data from the internal buffer int snd_rawmidi_transmit_peek struct snd_rawmidi_substream * substream unsigned char * buffer int count substream the rawmidi substream buffer the buffer pointer count data size to transfer Copies data from the internal output buffer to the given buffer. Call this in the interrupt handler when the midi output is ready, and call snd_rawmidi_transmit_ack after the transmission is finished. The size of copied data, or a negative error code on failure. Kernel Hackers Manual July 2017 __snd_rawmidi_transmit_ack 9 4.1.27 __snd_rawmidi_transmit_ack acknowledge the transmission int __snd_rawmidi_transmit_ack struct snd_rawmidi_substream * substream int count substream the rawmidi substream count the transferred count This is a variant of __snd_rawmidi_transmit_ack without spinlock. Kernel Hackers Manual July 2017 snd_rawmidi_transmit_ack 9 4.1.27 snd_rawmidi_transmit_ack acknowledge the transmission int snd_rawmidi_transmit_ack struct snd_rawmidi_substream * substream int count substream the rawmidi substream count the transferred count Advances the hardware pointer for the internal output buffer with the given size and updates the condition. Call after the transmission is finished. The advanced size if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_rawmidi_transmit 9 4.1.27 snd_rawmidi_transmit copy from the buffer to the device int snd_rawmidi_transmit struct snd_rawmidi_substream * substream unsigned char * buffer int count substream the rawmidi substream buffer the buffer pointer count the data size to transfer Copies data from the buffer to the device and advances the pointer. The copied size if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_rawmidi_new 9 4.1.27 snd_rawmidi_new create a rawmidi instance int snd_rawmidi_new struct snd_card * card char * id int device int output_count int input_count struct snd_rawmidi ** rrawmidi card the card instance id the id string device the device index output_count the number of output streams input_count the number of input streams rrawmidi the pointer to store the new rawmidi instance Creates a new rawmidi instance. Use snd_rawmidi_set_ops to set the operators to the new instance. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_rawmidi_set_ops 9 4.1.27 snd_rawmidi_set_ops set the rawmidi operators void snd_rawmidi_set_ops struct snd_rawmidi * rmidi int stream struct snd_rawmidi_ops * ops rmidi the rawmidi instance stream the stream direction, SNDRV_RAWMIDI_STREAM_XXX ops the operator table Sets the rawmidi operators for the given stream direction. Kernel Hackers Manual July 2017 snd_mpu401_uart_interrupt 9 4.1.27 snd_mpu401_uart_interrupt generic MPU401-UART interrupt handler irqreturn_t snd_mpu401_uart_interrupt int irq void * dev_id irq the irq number dev_id mpu401 instance Processes the interrupt for MPU401-UART i/o. IRQ_HANDLED if the interrupt was handled. IRQ_NONE otherwise. Kernel Hackers Manual July 2017 snd_mpu401_uart_interrupt_tx 9 4.1.27 snd_mpu401_uart_interrupt_tx generic MPU401-UART transmit irq handler irqreturn_t snd_mpu401_uart_interrupt_tx int irq void * dev_id irq the irq number dev_id mpu401 instance Processes the interrupt for MPU401-UART output. IRQ_HANDLED if the interrupt was handled. IRQ_NONE otherwise. Kernel Hackers Manual July 2017 snd_mpu401_uart_new 9 4.1.27 snd_mpu401_uart_new create an MPU401-UART instance int snd_mpu401_uart_new struct snd_card * card int device unsigned short hardware unsigned long port unsigned int info_flags int irq struct snd_rawmidi ** rrawmidi card the card instance device the device index, zero-based hardware the hardware type, MPU401_HW_XXXX port the base address of MPU401 port info_flags bitflags MPU401_INFO_XXX irq the ISA irq number, -1 if not to be allocated rrawmidi the pointer to store the new rawmidi instance Creates a new MPU-401 instance. Note that the rawmidi instance is returned on the rrawmidi argument, not the mpu401 instance itself. To access to the mpu401 instance, cast from rawmidi->private_data (with struct snd_mpu401 magic-cast). Zero if successful, or a negative error code. Kernel Hackers Manual July 2017 snd_iprintf 9 4.1.27 snd_iprintf printf on the procfs buffer int snd_iprintf struct snd_info_buffer * buffer const char * fmt ... buffer the procfs buffer fmt the printf format ... variable arguments Outputs the string on the procfs buffer just like printf. The size of output string, or a negative error code. Kernel Hackers Manual July 2017 snd_info_get_line 9 4.1.27 snd_info_get_line read one line from the procfs buffer int snd_info_get_line struct snd_info_buffer * buffer char * line int len buffer the procfs buffer line the buffer to store len the max. buffer size Reads one line from the buffer and stores the string. Zero if successful, or 1 if error or EOF. Kernel Hackers Manual July 2017 snd_info_get_str 9 4.1.27 snd_info_get_str parse a string token const char * snd_info_get_str char * dest const char * src int len dest the buffer to store the string token src the original string len the max. length of token - 1 Parses the original string and copy a token to the given string buffer. The updated pointer of the original string so that it can be used for the next call. Kernel Hackers Manual July 2017 snd_info_create_module_entry 9 4.1.27 snd_info_create_module_entry create an info entry for the given module struct snd_info_entry * snd_info_create_module_entry struct module * module const char * name struct snd_info_entry * parent module the module pointer name the file name parent the parent directory Creates a new info entry and assigns it to the given module. The pointer of the new instance, or NULL on failure. Kernel Hackers Manual July 2017 snd_info_create_card_entry 9 4.1.27 snd_info_create_card_entry create an info entry for the given card struct snd_info_entry * snd_info_create_card_entry struct snd_card * card const char * name struct snd_info_entry * parent card the card instance name the file name parent the parent directory Creates a new info entry and assigns it to the given card. The pointer of the new instance, or NULL on failure. Kernel Hackers Manual July 2017 snd_card_proc_new 9 4.1.27 snd_card_proc_new create an info entry for the given card int snd_card_proc_new struct snd_card * card const char * name struct snd_info_entry ** entryp card the card instance name the file name entryp the pointer to store the new info entry Creates a new info entry and assigns it to the given card. Unlike snd_info_create_card_entry, this function registers the info entry as an ALSA device component, so that it can be unregistered/released without explicit call. Also, you don't have to register this entry via snd_info_register, since this will be registered by snd_card_register automatically. The parent is assumed as card->proc_root. For releasing this entry, use snd_device_free instead of snd_info_free_entry. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_info_free_entry 9 4.1.27 snd_info_free_entry release the info entry void snd_info_free_entry struct snd_info_entry * entry entry the info entry Releases the info entry. Don't call this after registered. Kernel Hackers Manual July 2017 snd_info_register 9 4.1.27 snd_info_register register the info entry int snd_info_register struct snd_info_entry * entry entry the info entry Registers the proc info entry. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_compress_register 9 4.1.27 snd_compress_register register compressed device int snd_compress_register struct snd_compr * device device compressed device to register Kernel Hackers Manual July 2017 struct snd_compressed_buffer 9 4.1.27 struct snd_compressed_buffer compressed buffer struct snd_compressed_buffer { __u32 fragment_size; __u32 fragments; }; fragment_size size of buffer fragment in bytes fragments number of such fragments Kernel Hackers Manual July 2017 struct snd_compr_params 9 4.1.27 struct snd_compr_params compressed stream params struct snd_compr_params { struct snd_compressed_buffer buffer; struct snd_codec codec; __u8 no_wake_mode; }; buffer buffer description codec codec parameters no_wake_mode dont wake on fragment elapsed Kernel Hackers Manual July 2017 struct snd_compr_tstamp 9 4.1.27 struct snd_compr_tstamp timestamp descriptor struct snd_compr_tstamp { __u32 byte_offset; __u32 copied_total; __u32 pcm_frames; __u32 pcm_io_frames; __u32 sampling_rate; }; byte_offset Byte offset in ring buffer to DSP copied_total Total number of bytes copied from/to ring buffer to/by DSP pcm_frames Frames decoded or encoded by DSP. This field will evolve by large steps and should only be used to monitor encoding/decoding progress. It shall not be used for timing estimates. pcm_io_frames Frames rendered or received by DSP into a mixer or an audio output/input. This field should be used for A/V sync or time estimates. sampling_rate sampling rate of audio Kernel Hackers Manual July 2017 struct snd_compr_avail 9 4.1.27 struct snd_compr_avail avail descriptor struct snd_compr_avail { __u64 avail; struct snd_compr_tstamp tstamp; }; avail Number of bytes available in ring buffer for writing/reading tstamp timestamp information Kernel Hackers Manual July 2017 struct snd_compr_caps 9 4.1.27 struct snd_compr_caps caps descriptor struct snd_compr_caps { __u32 num_codecs; __u32 direction; __u32 min_fragment_size; __u32 max_fragment_size; __u32 min_fragments; __u32 max_fragments; __u32 codecs[MAX_NUM_CODECS]; __u32 reserved[11]; }; num_codecs number of codecs supported direction direction supported. Of type snd_compr_direction min_fragment_size minimum fragment supported by DSP max_fragment_size maximum fragment supported by DSP min_fragments min fragments supported by DSP max_fragments max fragments supported by DSP codecs[MAX_NUM_CODECS] pointer to array of codecs reserved[11] reserved field Kernel Hackers Manual July 2017 struct snd_compr_codec_caps 9 4.1.27 struct snd_compr_codec_caps query capability of codec struct snd_compr_codec_caps { __u32 codec; __u32 num_descriptors; struct snd_codec_desc descriptor[MAX_NUM_CODEC_DESCRIPTORS]; }; codec codec for which capability is queried num_descriptors number of codec descriptors descriptor[MAX_NUM_CODEC_DESCRIPTORS] array of codec capability descriptor Kernel Hackers Manual July 2017 enum sndrv_compress_encoder 9 4.1.27 enum sndrv_compress_encoder enum sndrv_compress_encoder { SNDRV_COMPRESS_ENCODER_PADDING, SNDRV_COMPRESS_ENCODER_DELAY }; SNDRV_COMPRESS_ENCODER_PADDING no of samples appended by the encoder at the end of the track SNDRV_COMPRESS_ENCODER_DELAY no of samples inserted by the encoder at the beginning of the track Kernel Hackers Manual July 2017 struct snd_compr_metadata 9 4.1.27 struct snd_compr_metadata compressed stream metadata struct snd_compr_metadata { __u32 key; __u32 value[8]; }; key key id value[8] key value Kernel Hackers Manual July 2017 SNDRV_COMPRESS_IOCTL_VERSION 9 4.1.27 SNDRV_COMPRESS_IOCTL_VERSION SNDRV_COMPRESS_IOCTL_VERSION None Query capability of DSP Query capability of a codec Set codec and stream parameters only codec params can be changed runtime and stream params cant be Query codec params get the current timestamp value get the current buffer avail value. This also queries the tstamp properties Pause the running stream resume a paused stream Start a stream stop a running stream, discarding ring buffer content and the buffers currently with DSP Play till end of buffers and stop after that Query the API version Kernel Hackers Manual July 2017 struct snd_enc_vorbis 9 4.1.27 struct snd_enc_vorbis struct snd_enc_vorbis { __s32 quality; __u32 managed; __u32 max_bit_rate; __u32 min_bit_rate; __u32 downmix; }; quality Sets encoding quality to n, between -1 (low) and 10 (high). In the default mode of operation, the quality level is 3. Normal quality range is 0 - 10. managed Boolean. Set bitrate management mode. This turns off the normal VBR encoding, but allows hard or soft bitrate constraints to be enforced by the encoder. This mode can be slower, and may also be lower quality. It is primarily useful for streaming. max_bit_rate Enabled only if managed is TRUE min_bit_rate Enabled only if managed is TRUE downmix Boolean. Downmix input from stereo to mono (has no effect on non-stereo streams). Useful for lower-bitrate encoding. These options were extracted from the OpenMAX IL spec and Gstreamer vorbisenc properties For best quality users should specify VBR mode and set quality levels. Kernel Hackers Manual July 2017 struct snd_enc_real 9 4.1.27 struct snd_enc_real struct snd_enc_real { __u32 quant_bits; __u32 start_region; __u32 num_regions; }; quant_bits number of coupling quantization bits in the stream start_region coupling start region in the stream num_regions number of regions value These options were extracted from the OpenMAX IL spec Kernel Hackers Manual July 2017 struct snd_enc_flac 9 4.1.27 struct snd_enc_flac struct snd_enc_flac { __u32 num; __u32 gain; }; num serial number, valid only for OGG formats needs to be set by application gain Add replay gain tags These options were extracted from the FLAC online documentation //flac.sourceforge.net/documentation_tools_flac.html To make the API simpler, it is assumed that the user will select quality profiles. Additional options that affect encoding quality and speed can be added at a later stage if needed. By default the Subset format is used by encoders. TAGS such as pictures, etc, cannot be handled by an offloaded encoder and are not supported in this API. Kernel Hackers Manual July 2017 struct snd_compr_runtime 9 4.1.27 struct snd_compr_runtime struct snd_compr_runtime { snd_pcm_state_t state; struct snd_compr_ops * ops; void * buffer; u64 buffer_size; u32 fragment_size; u32 fragments; u64 total_bytes_available; u64 total_bytes_transferred; wait_queue_head_t sleep; void * private_data; }; state stream state ops pointer to DSP callbacks buffer pointer to kernel buffer, valid only when not in mmap mode or DSP doesn't implement copy buffer_size size of the above buffer fragment_size size of buffer fragment in bytes fragments number of such fragments total_bytes_available cumulative number of bytes made available in the ring buffer total_bytes_transferred cumulative bytes transferred by offload DSP sleep poll sleep private_data driver private data pointer Kernel Hackers Manual July 2017 struct snd_compr_stream 9 4.1.27 struct snd_compr_stream struct snd_compr_stream { const char * name; struct snd_compr_ops * ops; struct snd_compr_runtime * runtime; struct snd_compr * device; enum snd_compr_direction direction; bool metadata_set; bool next_track; void * private_data; }; name device name ops pointer to DSP callbacks runtime pointer to runtime structure device device pointer direction stream direction, playback/recording metadata_set metadata set flag, true when set next_track has userspace signal next track transition, true when set private_data pointer to DSP private data Kernel Hackers Manual July 2017 struct snd_compr_ops 9 4.1.27 struct snd_compr_ops struct snd_compr_ops { int (* open) (struct snd_compr_stream *stream); int (* free) (struct snd_compr_stream *stream); int (* set_params) (struct snd_compr_stream *stream,struct snd_compr_params *params); int (* get_params) (struct snd_compr_stream *stream,struct snd_codec *params); int (* set_metadata) (struct snd_compr_stream *stream,struct snd_compr_metadata *metadata); int (* get_metadata) (struct snd_compr_stream *stream,struct snd_compr_metadata *metadata); int (* trigger) (struct snd_compr_stream *stream, int cmd); int (* pointer) (struct snd_compr_stream *stream,struct snd_compr_tstamp *tstamp); int (* copy) (struct snd_compr_stream *stream, char __user *buf,size_t count); int (* mmap) (struct snd_compr_stream *stream,struct vm_area_struct *vma); int (* ack) (struct snd_compr_stream *stream, size_t bytes); int (* get_caps) (struct snd_compr_stream *stream,struct snd_compr_caps *caps); int (* get_codec_caps) (struct snd_compr_stream *stream,struct snd_compr_codec_caps *codec); }; open Open the compressed stream This callback is mandatory and shall keep dsp ready to receive the stream parameter free Close the compressed stream, mandatory set_params Sets the compressed stream parameters, mandatory This can be called in during stream creation only to set codec params and the stream properties get_params retrieve the codec parameters, mandatory set_metadata Set the metadata values for a stream get_metadata retrieves the requested metadata values from stream trigger Trigger operations like start, pause, resume, drain, stop. This callback is mandatory pointer Retrieve current h/w pointer information. Mandatory copy Copy the compressed data to/from userspace, Optional Can't be implemented if DSP supports mmap mmap DSP mmap method to mmap DSP memory ack Ack for DSP when data is written to audio buffer, Optional Not valid if copy is implemented get_caps Retrieve DSP capabilities, mandatory get_codec_caps Retrieve capabilities for a specific codec, mandatory Kernel Hackers Manual July 2017 struct snd_compr 9 4.1.27 struct snd_compr struct snd_compr { const char * name; struct device dev; struct snd_compr_ops * ops; void * private_data; struct snd_card * card; unsigned int direction; struct mutex lock; int device; }; name DSP device name dev associated device instance ops pointer to DSP callbacks private_data pointer to DSP pvt data card sound card pointer direction Playback or capture direction lock device lock device device id Kernel Hackers Manual July 2017 struct snd_soc_jack_pin 9 4.1.27 struct snd_soc_jack_pin Describes a pin to update based on jack detection struct snd_soc_jack_pin { const char * pin; int mask; bool invert; }; pin name of the pin to update mask bits to check for in reported jack status invert if non-zero then pin is enabled when status is not reported Kernel Hackers Manual July 2017 struct snd_soc_jack_zone 9 4.1.27 struct snd_soc_jack_zone Describes voltage zones of jack detection struct snd_soc_jack_zone { unsigned int min_mv; unsigned int max_mv; unsigned int jack_type; unsigned int debounce_time; }; min_mv start voltage in mv max_mv end voltage in mv jack_type type of jack that is expected for this voltage debounce_time debounce_time for jack, codec driver should wait for this duration before reading the adc for voltages @:list: list container Kernel Hackers Manual July 2017 struct snd_soc_jack_gpio 9 4.1.27 struct snd_soc_jack_gpio Describes a gpio pin for jack detection struct snd_soc_jack_gpio { unsigned int gpio; unsigned int idx; const char * name; int report; int invert; bool wake; int (* jack_status_check) (void *data); }; gpio legacy gpio number idx gpio descriptor index within the function of the GPIO consumer device gpiod_dev GPIO consumer device name gpio name. Also as connection ID for the GPIO consumer device function name lookup report value to report when jack detected invert report presence in low state wake enable as wake source jack_status_check callback function which overrides the detection to provide more complex checks (eg, reading an ADC). Kernel Hackers Manual July 2017 snd_soc_component_to_codec 9 4.1.27 snd_soc_component_to_codec Casts a component to the CODEC it is embedded in struct snd_soc_codec * snd_soc_component_to_codec struct snd_soc_component * component component The component to cast to a CODEC This function must only be used on components that are known to be CODECs. Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_component_to_platform 9 4.1.27 snd_soc_component_to_platform Casts a component to the platform it is embedded in struct snd_soc_platform * snd_soc_component_to_platform struct snd_soc_component * component component The component to cast to a platform This function must only be used on components that are known to be platforms. Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_dapm_to_component 9 4.1.27 snd_soc_dapm_to_component Casts a DAPM context to the component it is embedded in struct snd_soc_component * snd_soc_dapm_to_component struct snd_soc_dapm_context * dapm dapm The DAPM context to cast to the component This function must only be used on DAPM contexts that are known to be part of a component (e.g. in a component driver). Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_dapm_to_codec 9 4.1.27 snd_soc_dapm_to_codec Casts a DAPM context to the CODEC it is embedded in struct snd_soc_codec * snd_soc_dapm_to_codec struct snd_soc_dapm_context * dapm dapm The DAPM context to cast to the CODEC This function must only be used on DAPM contexts that are known to be part of a CODEC (e.g. in a CODEC driver). Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_dapm_to_platform 9 4.1.27 snd_soc_dapm_to_platform Casts a DAPM context to the platform it is embedded in struct snd_soc_platform * snd_soc_dapm_to_platform struct snd_soc_dapm_context * dapm dapm The DAPM context to cast to the platform. This function must only be used on DAPM contexts that are known to be part of a platform (e.g. in a platform driver). Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_component_get_dapm 9 4.1.27 snd_soc_component_get_dapm Returns the DAPM context associated with a component struct snd_soc_dapm_context * snd_soc_component_get_dapm struct snd_soc_component * component component The component for which to get the DAPM context Kernel Hackers Manual July 2017 snd_soc_dapm_kcontrol_codec 9 4.1.27 snd_soc_dapm_kcontrol_codec Returns the codec associated to a kcontrol struct snd_soc_codec * snd_soc_dapm_kcontrol_codec struct snd_kcontrol * kcontrol kcontrol The kcontrol This function must only be used on DAPM contexts that are known to be part of a CODEC (e.g. in a CODEC driver). Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_cache_sync 9 4.1.27 snd_soc_cache_sync Sync the register cache with the hardware int snd_soc_cache_sync struct snd_soc_codec * codec codec CODEC to sync This function will call regcache_sync Kernel Hackers Manual July 2017 snd_soc_codec_init_regmap 9 4.1.27 snd_soc_codec_init_regmap Initialize regmap instance for the CODEC void snd_soc_codec_init_regmap struct snd_soc_codec * codec struct regmap * regmap codec The CODEC for which to initialize the regmap instance regmap The regmap instance that should be used by the CODEC This function allows deferred assignment of the regmap instance that is associated with the CODEC. Only use this if the regmap instance is not yet ready when the CODEC is registered. The function must also be called before the first IO attempt of the CODEC. Kernel Hackers Manual July 2017 snd_soc_codec_exit_regmap 9 4.1.27 snd_soc_codec_exit_regmap De-initialize regmap instance for the CODEC void snd_soc_codec_exit_regmap struct snd_soc_codec * codec codec The CODEC for which to de-initialize the regmap instance Calls regmap_exit on the regmap instance associated to the CODEC and removes the regmap instance from the CODEC. This function should only be used if snd_soc_codec_init_regmap was used to initialize the regmap instance. Kernel Hackers Manual July 2017 snd_soc_kcontrol_component 9 4.1.27 snd_soc_kcontrol_component Returns the component that registered the control struct snd_soc_component * snd_soc_kcontrol_component struct snd_kcontrol * kcontrol kcontrol The control for which to get the component This function will work correctly if the control has been registered for a component. Either with snd_soc_add_codec_controls or snd_soc_add_platform_controls or via table based setup for either a CODEC, a platform or component driver. Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_kcontrol_codec 9 4.1.27 snd_soc_kcontrol_codec Returns the CODEC that registered the control struct snd_soc_codec * snd_soc_kcontrol_codec struct snd_kcontrol * kcontrol kcontrol The control for which to get the CODEC This function will only work correctly if the control has been registered with snd_soc_add_codec_controls or via table based setup of snd_soc_codec_driver. Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_kcontrol_platform 9 4.1.27 snd_soc_kcontrol_platform Returns the platform that registered the control struct snd_soc_platform * snd_soc_kcontrol_platform struct snd_kcontrol * kcontrol kcontrol The control for which to get the platform This function will only work correctly if the control has been registered with snd_soc_add_platform_controls or via table based setup of a snd_soc_platform_driver. Otherwise the behavior is undefined. Kernel Hackers Manual July 2017 snd_soc_runtime_set_dai_fmt 9 4.1.27 snd_soc_runtime_set_dai_fmt Change DAI link format for a ASoC runtime int snd_soc_runtime_set_dai_fmt struct snd_soc_pcm_runtime * rtd unsigned int dai_fmt rtd The runtime for which the DAI link format should be changed dai_fmt The new DAI link format This function updates the DAI link format for all DAIs connected to the DAI link for the specified runtime. For setups with a static format set the dai_fmt field in the corresponding snd_dai_link struct instead of using this function. Returns 0 on success, otherwise a negative error code. Kernel Hackers Manual July 2017 snd_soc_cnew 9 4.1.27 snd_soc_cnew create new control struct snd_kcontrol * snd_soc_cnew const struct snd_kcontrol_new * _template void * data const char * long_name const char * prefix _template control template data control private data long_name control long name prefix control name prefix Create a new mixer control from a template control. Returns 0 for success, else error. Kernel Hackers Manual July 2017 snd_soc_add_component_controls 9 4.1.27 snd_soc_add_component_controls Add an array of controls to a component. int snd_soc_add_component_controls struct snd_soc_component * component const struct snd_kcontrol_new * controls unsigned int num_controls component Component to add controls to controls Array of controls to add num_controls Number of elements in the array 0 for success, else error. Kernel Hackers Manual July 2017 snd_soc_add_codec_controls 9 4.1.27 snd_soc_add_codec_controls add an array of controls to a codec. Convenience function to add a list of controls. Many codecs were duplicating this code. int snd_soc_add_codec_controls struct snd_soc_codec * codec const struct snd_kcontrol_new * controls unsigned int num_controls codec codec to add controls to controls array of controls to add num_controls number of elements in the array Return 0 for success, else error. Kernel Hackers Manual July 2017 snd_soc_add_platform_controls 9 4.1.27 snd_soc_add_platform_controls add an array of controls to a platform. Convenience function to add a list of controls. int snd_soc_add_platform_controls struct snd_soc_platform * platform const struct snd_kcontrol_new * controls unsigned int num_controls platform platform to add controls to controls array of controls to add num_controls number of elements in the array Return 0 for success, else error. Kernel Hackers Manual July 2017 snd_soc_add_card_controls 9 4.1.27 snd_soc_add_card_controls add an array of controls to a SoC card. Convenience function to add a list of controls. int snd_soc_add_card_controls struct snd_soc_card * soc_card const struct snd_kcontrol_new * controls int num_controls soc_card SoC card to add controls to controls array of controls to add num_controls number of elements in the array Return 0 for success, else error. Kernel Hackers Manual July 2017 snd_soc_add_dai_controls 9 4.1.27 snd_soc_add_dai_controls add an array of controls to a DAI. Convienience function to add a list of controls. int snd_soc_add_dai_controls struct snd_soc_dai * dai const struct snd_kcontrol_new * controls int num_controls dai DAI to add controls to controls array of controls to add num_controls number of elements in the array Return 0 for success, else error. Kernel Hackers Manual July 2017 snd_soc_dai_set_sysclk 9 4.1.27 snd_soc_dai_set_sysclk configure DAI system or master clock. int snd_soc_dai_set_sysclk struct snd_soc_dai * dai int clk_id unsigned int freq int dir dai DAI clk_id DAI specific clock ID freq new clock frequency in Hz dir new clock direction - input/output. Configures the DAI master (MCLK) or system (SYSCLK) clocking. Kernel Hackers Manual July 2017 snd_soc_codec_set_sysclk 9 4.1.27 snd_soc_codec_set_sysclk configure CODEC system or master clock. int snd_soc_codec_set_sysclk struct snd_soc_codec * codec int clk_id int source unsigned int freq int dir codec CODEC clk_id DAI specific clock ID source Source for the clock freq new clock frequency in Hz dir new clock direction - input/output. Configures the CODEC master (MCLK) or system (SYSCLK) clocking. Kernel Hackers Manual July 2017 snd_soc_dai_set_clkdiv 9 4.1.27 snd_soc_dai_set_clkdiv configure DAI clock dividers. int snd_soc_dai_set_clkdiv struct snd_soc_dai * dai int div_id int div dai DAI div_id DAI specific clock divider ID div new clock divisor. Configures the clock dividers. This is used to derive the best DAI bit and frame clocks from the system or master clock. It's best to set the DAI bit and frame clocks as low as possible to save system power. Kernel Hackers Manual July 2017 snd_soc_dai_set_pll 9 4.1.27 snd_soc_dai_set_pll configure DAI PLL. int snd_soc_dai_set_pll struct snd_soc_dai * dai int pll_id int source unsigned int freq_in unsigned int freq_out dai DAI pll_id DAI specific PLL ID source DAI specific source for the PLL freq_in PLL input clock frequency in Hz freq_out requested PLL output clock frequency in Hz Configures and enables PLL to generate output clock based on input clock. Kernel Hackers Manual July 2017 snd_soc_dai_set_bclk_ratio 9 4.1.27 snd_soc_dai_set_bclk_ratio configure BCLK to sample rate ratio. int snd_soc_dai_set_bclk_ratio struct snd_soc_dai * dai unsigned int ratio dai DAI ratio Ratio of BCLK to Sample rate. ratio -- undescribed -- Configures the DAI for a preset BCLK to sample rate ratio. Kernel Hackers Manual July 2017 snd_soc_dai_set_fmt 9 4.1.27 snd_soc_dai_set_fmt configure DAI hardware audio format. int snd_soc_dai_set_fmt struct snd_soc_dai * dai unsigned int fmt dai DAI fmt SND_SOC_DAIFMT_ format value. Configures the DAI hardware format and clocking. Kernel Hackers Manual July 2017 snd_soc_dai_set_tdm_slot 9 4.1.27 snd_soc_dai_set_tdm_slot Configures a DAI for TDM operation int snd_soc_dai_set_tdm_slot struct snd_soc_dai * dai unsigned int tx_mask unsigned int rx_mask int slots int slot_width dai The DAI to configure tx_mask bitmask representing active TX slots. rx_mask bitmask representing active RX slots. slots Number of slots in use. slot_width Width in bits for each slot. This function configures the specified DAI for TDM operation. slot contains the total number of slots of the TDM stream and slot_with the width of each slot in bit clock cycles. tx_mask and rx_mask are bitmasks specifying the active slots of the TDM stream for the specified DAI, i.e. which slots the DAI should write to or read from. If a bit is set the corresponding slot is active, if a bit is cleared the corresponding slot is inactive. Bit 0 maps to the first slot, bit 1 to the second slot and so on. The first active slot maps to the first channel of the DAI, the second active slot to the second channel and so on. TDM mode can be disabled by passing 0 for slots. In this case tx_mask, rx_mask and slot_width will be ignored. Returns 0 on success, a negative error code otherwise. Kernel Hackers Manual July 2017 snd_soc_dai_set_channel_map 9 4.1.27 snd_soc_dai_set_channel_map configure DAI audio channel map int snd_soc_dai_set_channel_map struct snd_soc_dai * dai unsigned int tx_num unsigned int * tx_slot unsigned int rx_num unsigned int * rx_slot dai DAI tx_num how many TX channels tx_slot pointer to an array which imply the TX slot number channel 0~num-1 uses rx_num how many RX channels rx_slot pointer to an array which imply the RX slot number channel 0~num-1 uses configure the relationship between channel number and TDM slot number. Kernel Hackers Manual July 2017 snd_soc_dai_set_tristate 9 4.1.27 snd_soc_dai_set_tristate configure DAI system or master clock. int snd_soc_dai_set_tristate struct snd_soc_dai * dai int tristate dai DAI tristate tristate enable Tristates the DAI so that others can use it. Kernel Hackers Manual July 2017 snd_soc_dai_digital_mute 9 4.1.27 snd_soc_dai_digital_mute configure DAI system or master clock. int snd_soc_dai_digital_mute struct snd_soc_dai * dai int mute int direction dai DAI mute mute enable direction stream to mute Mutes the DAI DAC. Kernel Hackers Manual July 2017 snd_soc_register_card 9 4.1.27 snd_soc_register_card Register a card with the ASoC core int snd_soc_register_card struct snd_soc_card * card card Card to register Kernel Hackers Manual July 2017 snd_soc_unregister_card 9 4.1.27 snd_soc_unregister_card Unregister a card with the ASoC core int snd_soc_unregister_card struct snd_soc_card * card card Card to unregister Kernel Hackers Manual July 2017 snd_soc_component_init_regmap 9 4.1.27 snd_soc_component_init_regmap Initialize regmap instance for the component void snd_soc_component_init_regmap struct snd_soc_component * component struct regmap * regmap component The component for which to initialize the regmap instance regmap The regmap instance that should be used by the component This function allows deferred assignment of the regmap instance that is associated with the component. Only use this if the regmap instance is not yet ready when the component is registered. The function must also be called before the first IO attempt of the component. Kernel Hackers Manual July 2017 snd_soc_component_exit_regmap 9 4.1.27 snd_soc_component_exit_regmap De-initialize regmap instance for the component void snd_soc_component_exit_regmap struct snd_soc_component * component component The component for which to de-initialize the regmap instance Calls regmap_exit on the regmap instance associated to the component and removes the regmap instance from the component. This function should only be used if snd_soc_component_init_regmap was used to initialize the regmap instance. Kernel Hackers Manual July 2017 snd_soc_unregister_component 9 4.1.27 snd_soc_unregister_component Unregister a component from the ASoC core void snd_soc_unregister_component struct device * dev dev -- undescribed -- Kernel Hackers Manual July 2017 snd_soc_add_platform 9 4.1.27 snd_soc_add_platform Add a platform to the ASoC core int snd_soc_add_platform struct device * dev struct snd_soc_platform * platform const struct snd_soc_platform_driver * platform_drv dev The parent device for the platform platform The platform to add platform_drv -- undescribed -- Kernel Hackers Manual July 2017 snd_soc_register_platform 9 4.1.27 snd_soc_register_platform Register a platform with the ASoC core int snd_soc_register_platform struct device * dev const struct snd_soc_platform_driver * platform_drv dev -- undescribed -- platform_drv -- undescribed -- Kernel Hackers Manual July 2017 snd_soc_remove_platform 9 4.1.27 snd_soc_remove_platform Remove a platform from the ASoC core void snd_soc_remove_platform struct snd_soc_platform * platform platform the platform to remove Kernel Hackers Manual July 2017 snd_soc_unregister_platform 9 4.1.27 snd_soc_unregister_platform Unregister a platform from the ASoC core void snd_soc_unregister_platform struct device * dev dev -- undescribed -- Kernel Hackers Manual July 2017 snd_soc_register_codec 9 4.1.27 snd_soc_register_codec Register a codec with the ASoC core int snd_soc_register_codec struct device * dev const struct snd_soc_codec_driver * codec_drv struct snd_soc_dai_driver * dai_drv int num_dai dev -- undescribed -- codec_drv -- undescribed -- dai_drv -- undescribed -- num_dai -- undescribed -- Kernel Hackers Manual July 2017 snd_soc_unregister_codec 9 4.1.27 snd_soc_unregister_codec Unregister a codec from the ASoC core void snd_soc_unregister_codec struct device * dev dev -- undescribed -- .//sound/soc/soc-cache.c Document generation inconsistency The template for this document tried to insert the structured comment from the file .//sound/soc/soc-cache.c at this point, but none was found. This dummy section is inserted to allow generation to continue. Kernel Hackers Manual July 2017 devm_snd_soc_register_component 9 4.1.27 devm_snd_soc_register_component resource managed component registration int devm_snd_soc_register_component struct device * dev const struct snd_soc_component_driver * cmpnt_drv struct snd_soc_dai_driver * dai_drv int num_dai dev Device used to manage component cmpnt_drv Component driver dai_drv DAI driver num_dai Number of DAIs to register Register a component with automatic unregistration when the device is unregistered. Kernel Hackers Manual July 2017 devm_snd_soc_register_platform 9 4.1.27 devm_snd_soc_register_platform resource managed platform registration int devm_snd_soc_register_platform struct device * dev const struct snd_soc_platform_driver * platform_drv dev Device used to manage platform platform_drv platform to register Register a platform driver with automatic unregistration when the device is unregistered. Kernel Hackers Manual July 2017 devm_snd_soc_register_card 9 4.1.27 devm_snd_soc_register_card resource managed card registration int devm_snd_soc_register_card struct device * dev struct snd_soc_card * card dev Device used to manage card card Card to register Register a card with automatic unregistration when the device is unregistered. Kernel Hackers Manual July 2017 devm_snd_dmaengine_pcm_register 9 4.1.27 devm_snd_dmaengine_pcm_register resource managed dmaengine PCM registration int devm_snd_dmaengine_pcm_register struct device * dev const struct snd_dmaengine_pcm_config * config unsigned int flags dev The parent device for the PCM device config Platform specific PCM configuration flags Platform specific quirks Register a dmaengine based PCM device with automatic unregistration when the device is unregistered. Kernel Hackers Manual July 2017 snd_soc_component_read 9 4.1.27 snd_soc_component_read Read register value int snd_soc_component_read struct snd_soc_component * component unsigned int reg unsigned int * val component Component to read from reg Register to read val Pointer to where the read value is stored 0 on success, a negative error code otherwise. Kernel Hackers Manual July 2017 snd_soc_component_write 9 4.1.27 snd_soc_component_write Write register value int snd_soc_component_write struct snd_soc_component * component unsigned int reg unsigned int val component Component to write to reg Register to write val Value to write to the register 0 on success, a negative error code otherwise. Kernel Hackers Manual July 2017 snd_soc_component_update_bits 9 4.1.27 snd_soc_component_update_bits Perform read/modify/write cycle int snd_soc_component_update_bits struct snd_soc_component * component unsigned int reg unsigned int mask unsigned int val component Component to update reg Register to update mask Mask that specifies which bits to update val New value for the bits specified by mask 1 if the operation was successful and the value of the register changed, 0 if the operation was successful, but the value did not change. Returns a negative error code otherwise. Kernel Hackers Manual July 2017 snd_soc_component_update_bits_async 9 4.1.27 snd_soc_component_update_bits_async Perform asynchronous read/modify/write cycle int snd_soc_component_update_bits_async struct snd_soc_component * component unsigned int reg unsigned int mask unsigned int val component Component to update reg Register to update mask Mask that specifies which bits to update val New value for the bits specified by mask This function is similar to snd_soc_component_update_bits, but the update operation is scheduled asynchronously. This means it may not be completed when the function returns. To make sure that all scheduled updates have been completed snd_soc_component_async_complete must be called. 1 if the operation was successful and the value of the register changed, 0 if the operation was successful, but the value did not change. Returns a negative error code otherwise. Kernel Hackers Manual July 2017 snd_soc_component_async_complete 9 4.1.27 snd_soc_component_async_complete Ensure asynchronous I/O has completed void snd_soc_component_async_complete struct snd_soc_component * component component Component for which to wait This function blocks until all asynchronous I/O which has previously been scheduled using snd_soc_component_update_bits_async has completed. Kernel Hackers Manual July 2017 snd_soc_component_test_bits 9 4.1.27 snd_soc_component_test_bits Test register for change int snd_soc_component_test_bits struct snd_soc_component * component unsigned int reg unsigned int mask unsigned int value component component reg Register to test mask Mask that specifies which bits to test value Value to test against Tests a register with a new value and checks if the new value is different from the old value. 1 for change, otherwise 0. Kernel Hackers Manual July 2017 snd_soc_update_bits 9 4.1.27 snd_soc_update_bits update codec register bits int snd_soc_update_bits struct snd_soc_codec * codec unsigned int reg unsigned int mask unsigned int value codec audio codec reg codec register mask register mask value new value Writes new register value. Returns 1 for change, 0 for no change, or negative error code. Kernel Hackers Manual July 2017 snd_soc_test_bits 9 4.1.27 snd_soc_test_bits test register for change int snd_soc_test_bits struct snd_soc_codec * codec unsigned int reg unsigned int mask unsigned int value codec audio codec reg codec register mask register mask value new value Tests a register with a new value and checks if the new value is different from the old value. Returns 1 for change else 0. Kernel Hackers Manual July 2017 snd_soc_set_runtime_hwparams 9 4.1.27 snd_soc_set_runtime_hwparams set the runtime hardware parameters int snd_soc_set_runtime_hwparams struct snd_pcm_substream * substream const struct snd_pcm_hardware * hw substream the pcm substream hw the hardware parameters Sets the substream runtime hardware parameters. Kernel Hackers Manual July 2017 snd_soc_dapm_kcontrol_dapm 9 4.1.27 snd_soc_dapm_kcontrol_dapm Returns the dapm context associated to a kcontrol struct snd_soc_dapm_context * snd_soc_dapm_kcontrol_dapm struct snd_kcontrol * kcontrol kcontrol The kcontrol This function must only be used on kcontrols that are known to have been registered for a CODEC. Otherwise the behaviour is undefined. Kernel Hackers Manual July 2017 snd_soc_dapm_sync_unlocked 9 4.1.27 snd_soc_dapm_sync_unlocked scan and power dapm paths int snd_soc_dapm_sync_unlocked struct snd_soc_dapm_context * dapm dapm DAPM context Walks all dapm audio paths and powers widgets according to their stream or path usage. Requires external locking. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_sync 9 4.1.27 snd_soc_dapm_sync scan and power dapm paths int snd_soc_dapm_sync struct snd_soc_dapm_context * dapm dapm DAPM context Walks all dapm audio paths and powers widgets according to their stream or path usage. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_add_routes 9 4.1.27 snd_soc_dapm_add_routes Add routes between DAPM widgets int snd_soc_dapm_add_routes struct snd_soc_dapm_context * dapm const struct snd_soc_dapm_route * route int num dapm DAPM context route audio routes num number of routes Connects 2 dapm widgets together via a named audio path. The sink is the widget receiving the audio signal, whilst the source is the sender of the audio signal. Returns 0 for success else error. On error all resources can be freed with a call to snd_soc_card_free. Kernel Hackers Manual July 2017 snd_soc_dapm_del_routes 9 4.1.27 snd_soc_dapm_del_routes Remove routes between DAPM widgets int snd_soc_dapm_del_routes struct snd_soc_dapm_context * dapm const struct snd_soc_dapm_route * route int num dapm DAPM context route audio routes num number of routes Removes routes from the DAPM context. Kernel Hackers Manual July 2017 snd_soc_dapm_weak_routes 9 4.1.27 snd_soc_dapm_weak_routes Mark routes between DAPM widgets as weak int snd_soc_dapm_weak_routes struct snd_soc_dapm_context * dapm const struct snd_soc_dapm_route * route int num dapm DAPM context route audio routes num number of routes Mark existing routes matching those specified in the passed array as being weak, meaning that they are ignored for the purpose of power decisions. The main intended use case is for sidetone paths which couple audio between other independent paths if they are both active in order to make the combination work better at the user level but which aren't intended to be used. Note that CODEC drivers should not use this as sidetone type paths can frequently also be used as bypass paths. Kernel Hackers Manual July 2017 snd_soc_dapm_new_widgets 9 4.1.27 snd_soc_dapm_new_widgets add new dapm widgets int snd_soc_dapm_new_widgets struct snd_soc_card * card card -- undescribed -- Checks the codec for any new dapm widgets and creates them if found. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_get_volsw 9 4.1.27 snd_soc_dapm_get_volsw dapm mixer get callback int snd_soc_dapm_get_volsw struct snd_kcontrol * kcontrol struct snd_ctl_elem_value * ucontrol kcontrol mixer control ucontrol control element information Callback to get the value of a dapm mixer control. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_put_volsw 9 4.1.27 snd_soc_dapm_put_volsw dapm mixer set callback int snd_soc_dapm_put_volsw struct snd_kcontrol * kcontrol struct snd_ctl_elem_value * ucontrol kcontrol mixer control ucontrol control element information Callback to set the value of a dapm mixer control. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_get_enum_double 9 4.1.27 snd_soc_dapm_get_enum_double dapm enumerated double mixer get callback int snd_soc_dapm_get_enum_double struct snd_kcontrol * kcontrol struct snd_ctl_elem_value * ucontrol kcontrol mixer control ucontrol control element information Callback to get the value of a dapm enumerated double mixer control. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_put_enum_double 9 4.1.27 snd_soc_dapm_put_enum_double dapm enumerated double mixer set callback int snd_soc_dapm_put_enum_double struct snd_kcontrol * kcontrol struct snd_ctl_elem_value * ucontrol kcontrol mixer control ucontrol control element information Callback to set the value of a dapm enumerated double mixer control. Returns 0 for success. Kernel Hackers Manual July 2017 snd_soc_dapm_info_pin_switch 9 4.1.27 snd_soc_dapm_info_pin_switch Info for a pin switch int snd_soc_dapm_info_pin_switch struct snd_kcontrol * kcontrol struct snd_ctl_elem_info * uinfo kcontrol mixer control uinfo control element information Callback to provide information about a pin switch control. Kernel Hackers Manual July 2017 snd_soc_dapm_get_pin_switch 9 4.1.27 snd_soc_dapm_get_pin_switch Get information for a pin switch int snd_soc_dapm_get_pin_switch struct snd_kcontrol * kcontrol struct snd_ctl_elem_value * ucontrol kcontrol mixer control ucontrol Value Kernel Hackers Manual July 2017 snd_soc_dapm_put_pin_switch 9 4.1.27 snd_soc_dapm_put_pin_switch Set information for a pin switch int snd_soc_dapm_put_pin_switch struct snd_kcontrol * kcontrol struct snd_ctl_elem_value * ucontrol kcontrol mixer control ucontrol Value Kernel Hackers Manual July 2017 snd_soc_dapm_new_controls 9 4.1.27 snd_soc_dapm_new_controls create new dapm controls int snd_soc_dapm_new_controls struct snd_soc_dapm_context * dapm const struct snd_soc_dapm_widget * widget int num dapm DAPM context widget widget array num number of widgets Creates new DAPM controls based upon the templates. Returns 0 for success else error. Kernel Hackers Manual July 2017 snd_soc_dapm_enable_pin_unlocked 9 4.1.27 snd_soc_dapm_enable_pin_unlocked enable pin. int snd_soc_dapm_enable_pin_unlocked struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Enables input/output pin and its parents or children widgets iff there is a valid audio route and active audio stream. Requires external locking. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_enable_pin 9 4.1.27 snd_soc_dapm_enable_pin enable pin. int snd_soc_dapm_enable_pin struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Enables input/output pin and its parents or children widgets iff there is a valid audio route and active audio stream. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_force_enable_pin_unlocked 9 4.1.27 snd_soc_dapm_force_enable_pin_unlocked force a pin to be enabled int snd_soc_dapm_force_enable_pin_unlocked struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Enables input/output pin regardless of any other state. This is intended for use with microphone bias supplies used in microphone jack detection. Requires external locking. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_force_enable_pin 9 4.1.27 snd_soc_dapm_force_enable_pin force a pin to be enabled int snd_soc_dapm_force_enable_pin struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Enables input/output pin regardless of any other state. This is intended for use with microphone bias supplies used in microphone jack detection. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_disable_pin_unlocked 9 4.1.27 snd_soc_dapm_disable_pin_unlocked disable pin. int snd_soc_dapm_disable_pin_unlocked struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Disables input/output pin and its parents or children widgets. Requires external locking. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_disable_pin 9 4.1.27 snd_soc_dapm_disable_pin disable pin. int snd_soc_dapm_disable_pin struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Disables input/output pin and its parents or children widgets. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_nc_pin_unlocked 9 4.1.27 snd_soc_dapm_nc_pin_unlocked permanently disable pin. int snd_soc_dapm_nc_pin_unlocked struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Marks the specified pin as being not connected, disabling it along any parent or child widgets. At present this is identical to snd_soc_dapm_disable_pin but in future it will be extended to do additional things such as disabling controls which only affect paths through the pin. Requires external locking. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_nc_pin 9 4.1.27 snd_soc_dapm_nc_pin permanently disable pin. int snd_soc_dapm_nc_pin struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin pin name Marks the specified pin as being not connected, disabling it along any parent or child widgets. At present this is identical to snd_soc_dapm_disable_pin but in future it will be extended to do additional things such as disabling controls which only affect paths through the pin. snd_soc_dapm_sync needs to be called after this for DAPM to do any widget power switching. Kernel Hackers Manual July 2017 snd_soc_dapm_get_pin_status 9 4.1.27 snd_soc_dapm_get_pin_status get audio pin status int snd_soc_dapm_get_pin_status struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin audio signal pin endpoint (or start point) Get audio pin status - connected or disconnected. Returns 1 for connected otherwise 0. Kernel Hackers Manual July 2017 snd_soc_dapm_ignore_suspend 9 4.1.27 snd_soc_dapm_ignore_suspend ignore suspend status for DAPM endpoint int snd_soc_dapm_ignore_suspend struct snd_soc_dapm_context * dapm const char * pin dapm DAPM context pin audio signal pin endpoint (or start point) Mark the given endpoint or pin as ignoring suspend. When the system is disabled a path between two endpoints flagged as ignoring suspend will not be disabled. The path must already be enabled via normal means at suspend time, it will not be turned on if it was not already enabled. Kernel Hackers Manual July 2017 snd_soc_dapm_free 9 4.1.27 snd_soc_dapm_free free dapm resources void snd_soc_dapm_free struct snd_soc_dapm_context * dapm dapm DAPM context Free all dapm widgets and resources. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_prepare_slave_config 9 4.1.27 snd_dmaengine_pcm_prepare_slave_config Generic prepare_slave_config callback int snd_dmaengine_pcm_prepare_slave_config struct snd_pcm_substream * substream struct snd_pcm_hw_params * params struct dma_slave_config * slave_config substream PCM substream params hw_params slave_config DMA slave config to prepare This function can be used as a generic prepare_slave_config callback for platforms which make use of the snd_dmaengine_dai_dma_data struct for their DAI DMA data. Internally the function will first call snd_hwparams_to_dma_slave_config to fill in the slave config based on the hw_params, followed by snd_dmaengine_set_config_from_dai_data to fill in the remaining fields based on the DAI DMA data. Kernel Hackers Manual July 2017 snd_dmaengine_pcm_register 9 4.1.27 snd_dmaengine_pcm_register Register a dmaengine based PCM device int snd_dmaengine_pcm_register struct device * dev const struct snd_dmaengine_pcm_config * config unsigned int flags dev The parent device for the PCM device config Platform specific PCM configuration flags Platform specific quirks Kernel Hackers Manual July 2017 snd_dmaengine_pcm_unregister 9 4.1.27 snd_dmaengine_pcm_unregister Removes a dmaengine based PCM device void snd_dmaengine_pcm_unregister struct device * dev dev Parent device the PCM was register with Removes a dmaengine based PCM device previously registered with snd_dmaengine_pcm_register. Kernel Hackers Manual July 2017 snd_hwdep_new 9 4.1.27 snd_hwdep_new create a new hwdep instance int snd_hwdep_new struct snd_card * card char * id int device struct snd_hwdep ** rhwdep card the card instance id the id string device the device index (zero-based) rhwdep the pointer to store the new hwdep instance Creates a new hwdep instance with the given index on the card. The callbacks (hwdep->ops) must be set on the returned instance after this call manually by the caller. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 enum snd_jack_types 9 4.1.27 enum snd_jack_types Jack types which can be reported enum snd_jack_types { SND_JACK_HEADPHONE, SND_JACK_MICROPHONE, SND_JACK_HEADSET, SND_JACK_LINEOUT, SND_JACK_MECHANICAL, SND_JACK_VIDEOOUT, SND_JACK_AVOUT, SND_JACK_LINEIN, SND_JACK_BTN_0, SND_JACK_BTN_1, SND_JACK_BTN_2, SND_JACK_BTN_3, SND_JACK_BTN_4, SND_JACK_BTN_5 }; SND_JACK_HEADPHONE Headphone SND_JACK_MICROPHONE Microphone SND_JACK_HEADSET Headset SND_JACK_LINEOUT Line out SND_JACK_MECHANICAL Mechanical switch SND_JACK_VIDEOOUT Video out SND_JACK_AVOUT AV (Audio Video) out SND_JACK_LINEIN Line in SND_JACK_BTN_0 Button 0 SND_JACK_BTN_1 Button 1 SND_JACK_BTN_2 Button 2 SND_JACK_BTN_3 Button 3 SND_JACK_BTN_4 Button 4 SND_JACK_BTN_5 Button 5 These values are used as a bitmask. Note that this must be kept in sync with the lookup table in sound/core/jack.c. Kernel Hackers Manual July 2017 snd_jack_new 9 4.1.27 snd_jack_new Create a new jack int snd_jack_new struct snd_card * card const char * id int type struct snd_jack ** jjack card the card instance id an identifying string for this jack type a bitmask of enum snd_jack_type values that can be detected by this jack jjack Used to provide the allocated jack object to the caller. Creates a new jack object. Zero if successful, or a negative error code on failure. On success jjack will be initialised. Kernel Hackers Manual July 2017 snd_jack_set_parent 9 4.1.27 snd_jack_set_parent Set the parent device for a jack void snd_jack_set_parent struct snd_jack * jack struct device * parent jack The jack to configure parent The device to set as parent for the jack. Set the parent for the jack devices in the device tree. This function is only valid prior to registration of the jack. If no parent is configured then the parent device will be the sound card. Kernel Hackers Manual July 2017 snd_jack_set_key 9 4.1.27 snd_jack_set_key Set a key mapping on a jack int snd_jack_set_key struct snd_jack * jack enum snd_jack_types type int keytype jack The jack to configure type Jack report type for this key keytype Input layer key type to be reported Map a SND_JACK_BTN_ button type to an input layer key, allowing reporting of keys on accessories via the jack abstraction. If no mapping is provided but keys are enabled in the jack type then BTN_n numeric buttons will be reported. If jacks are not reporting via the input API this call will have no effect. Note that this is intended to be use by simple devices with small numbers of keys that can be reported. It is also possible to access the input device directly - devices with complex input capabilities on accessories should consider doing this rather than using this abstraction. This function may only be called prior to registration of the jack. Zero if successful, or a negative error code on failure. Kernel Hackers Manual July 2017 snd_jack_report 9 4.1.27 snd_jack_report Report the current status of a jack void snd_jack_report struct snd_jack * jack int status jack The jack to report status for status The current status of the jack Kernel Hackers Manual July 2017 snd_soc_card_jack_new 9 4.1.27 snd_soc_card_jack_new Create a new jack int snd_soc_card_jack_new struct snd_soc_card * card const char * id int type struct snd_soc_jack * jack struct snd_soc_jack_pin * pins unsigned int num_pins card ASoC card id an identifying string for this jack type a bitmask of enum snd_jack_type values that can be detected by this jack jack structure to use for the jack pins Array of jack pins to be added to the jack or NULL num_pins Number of elements in the pins array Creates a new jack object. Returns zero if successful, or a negative error code on failure. On success jack will be initialised. Kernel Hackers Manual July 2017 snd_soc_jack_report 9 4.1.27 snd_soc_jack_report Report the current status for a jack void snd_soc_jack_report struct snd_soc_jack * jack int status int mask jack the jack status a bitmask of enum snd_jack_type values that are currently detected. mask a bitmask of enum snd_jack_type values that being reported. If configured using snd_soc_jack_add_pins then the associated DAPM pins will be enabled or disabled as appropriate and DAPM synchronised. This function uses mutexes and should be called from a context which can sleep (such as a workqueue). Kernel Hackers Manual July 2017 snd_soc_jack_add_zones 9 4.1.27 snd_soc_jack_add_zones Associate voltage zones with jack int snd_soc_jack_add_zones struct snd_soc_jack * jack int count struct snd_soc_jack_zone * zones jack ASoC jack count Number of zones zones Array of zones After this function has been called the zones specified in the array will be associated with the jack. Kernel Hackers Manual July 2017 snd_soc_jack_get_type 9 4.1.27 snd_soc_jack_get_type Based on the mic bias value, this function returns the type of jack from the zones declared in the jack type int snd_soc_jack_get_type struct snd_soc_jack * jack int micbias_voltage jack ASoC jack micbias_voltage mic bias voltage at adc channel when jack is plugged in Based on the mic bias value passed, this function helps identify the type of jack from the already declared jack zones Kernel Hackers Manual July 2017 snd_soc_jack_add_pins 9 4.1.27 snd_soc_jack_add_pins Associate DAPM pins with an ASoC jack int snd_soc_jack_add_pins struct snd_soc_jack * jack int count struct snd_soc_jack_pin * pins jack ASoC jack count Number of pins pins Array of pins After this function has been called the DAPM pins specified in the pins array will have their status updated to reflect the current state of the jack whenever the jack status is updated. Kernel Hackers Manual July 2017 snd_soc_jack_notifier_register 9 4.1.27 snd_soc_jack_notifier_register Register a notifier for jack status void snd_soc_jack_notifier_register struct snd_soc_jack * jack struct notifier_block * nb jack ASoC jack nb Notifier block to register Register for notification of the current status of the jack. Note that it is not possible to report additional jack events in the callback from the notifier, this is intended to support applications such as enabling electrical detection only when a mechanical detection event has occurred. Kernel Hackers Manual July 2017 snd_soc_jack_notifier_unregister 9 4.1.27 snd_soc_jack_notifier_unregister Unregister a notifier for jack status void snd_soc_jack_notifier_unregister struct snd_soc_jack * jack struct notifier_block * nb jack ASoC jack nb Notifier block to unregister Stop notifying for status changes. Kernel Hackers Manual July 2017 snd_soc_jack_add_gpios 9 4.1.27 snd_soc_jack_add_gpios Associate GPIO pins with an ASoC jack int snd_soc_jack_add_gpios struct snd_soc_jack * jack int count struct snd_soc_jack_gpio * gpios jack ASoC jack count number of pins gpios array of gpio pins This function will request gpio, set data direction and request irq for each gpio in the array. Kernel Hackers Manual July 2017 snd_soc_jack_add_gpiods 9 4.1.27 snd_soc_jack_add_gpiods Associate GPIO descriptor pins with an ASoC jack int snd_soc_jack_add_gpiods struct device * gpiod_dev struct snd_soc_jack * jack int count struct snd_soc_jack_gpio * gpios gpiod_dev GPIO consumer device jack ASoC jack count number of pins gpios array of gpio pins This function will request gpio, set data direction and request irq for each gpio in the array. Kernel Hackers Manual July 2017 snd_soc_jack_free_gpios 9 4.1.27 snd_soc_jack_free_gpios Release GPIO pins' resources of an ASoC jack void snd_soc_jack_free_gpios struct snd_soc_jack * jack int count struct snd_soc_jack_gpio * gpios jack ASoC jack count number of pins gpios array of gpio pins Release gpio and irq resources for gpio pins associated with an ASoC jack. Kernel Hackers Manual July 2017 snd_dma_program 9 4.1.27 snd_dma_program program an ISA DMA transfer void snd_dma_program unsigned long dma unsigned long addr unsigned int size unsigned short mode dma the dma number addr the physical address of the buffer size the DMA transfer size mode the DMA transfer mode, DMA_MODE_XXX Programs an ISA DMA transfer for the given buffer. Kernel Hackers Manual July 2017 snd_dma_disable 9 4.1.27 snd_dma_disable stop the ISA DMA transfer void snd_dma_disable unsigned long dma dma the dma number Stops the ISA DMA transfer. Kernel Hackers Manual July 2017 snd_dma_pointer 9 4.1.27 snd_dma_pointer return the current pointer to DMA transfer buffer in bytes unsigned int snd_dma_pointer unsigned long dma unsigned int size dma the dma number size the dma transfer size The current pointer in DMA transfer buffer in bytes. Kernel Hackers Manual July 2017 snd_printk 9 4.1.27 snd_printk printk wrapper snd_printk fmt args... fmt format string args... variable arguments Works like printk but prints the file and the line of the caller when configured with CONFIG_SND_VERBOSE_PRINTK. Kernel Hackers Manual July 2017 snd_printd 9 4.1.27 snd_printd debug printk snd_printd fmt args... fmt format string args... variable arguments Works like snd_printk for debugging purposes. Ignored when CONFIG_SND_DEBUG is not set. Kernel Hackers Manual July 2017 snd_BUG 9 4.1.27 snd_BUG give a BUG warning message and stack trace snd_BUG None Calls WARN if CONFIG_SND_DEBUG is set. Ignored when CONFIG_SND_DEBUG is not set. Kernel Hackers Manual July 2017 snd_printd_ratelimit 9 4.1.27 snd_printd_ratelimit snd_printd_ratelimit None Kernel Hackers Manual July 2017 snd_BUG_ON 9 4.1.27 snd_BUG_ON debugging check macro snd_BUG_ON cond cond condition to evaluate Has the same behavior as WARN_ON when CONFIG_SND_DEBUG is set, otherwise just evaluates the conditional and returns the value. Kernel Hackers Manual July 2017 snd_printdd 9 4.1.27 snd_printdd debug printk snd_printdd format args... format format string args... variable arguments Works like snd_printk for debugging purposes. Ignored when CONFIG_SND_DEBUG_VERBOSE is not set.