struct device — The basic device structure
struct device {
struct device * parent;
struct device_private * p;
struct kobject kobj;
const char * init_name;
const struct device_type * type;
struct mutex mutex;
struct bus_type * bus;
struct device_driver * driver;
void * platform_data;
void * driver_data;
struct dev_pm_info power;
struct dev_pm_domain * pm_domain;
#ifdef CONFIG_PINCTRL
struct dev_pin_info * pins;
#endif
#ifdef CONFIG_NUMA
int numa_node;
#endif
u64 * dma_mask;
u64 coherent_dma_mask;
unsigned long dma_pfn_offset;
struct device_dma_parameters * dma_parms;
struct list_head dma_pools;
struct dma_coherent_mem * dma_mem;
#ifdef CONFIG_DMA_CMA
struct cma * cma_area;
#endif
struct dev_archdata archdata;
struct device_node * of_node;
struct fwnode_handle * fwnode;
dev_t devt;
u32 id;
spinlock_t devres_lock;
struct list_head devres_head;
struct klist_node knode_class;
struct class * class;
const struct attribute_group ** groups;
void (* release) (struct device *dev);
struct iommu_group * iommu_group;
bool offline_disabled:1;
bool offline:1;
}; The device's “parent” device, the device to which it is attached. In most cases, a parent device is some sort of bus or host controller. If parent is NULL, the device, is a top-level device, which is not usually what you want.
Holds the private data of the driver core portions of the device. See the comment of the struct device_private for detail.
A top-level, abstract class from which other classes are derived.
Initial name of the device.
The type of device. This identifies the device type and carries type-specific information.
Mutex to synchronize calls to its driver.
Type of bus device is on.
Which driver has allocated this
Platform data specific to the device.
Private pointer for driver specific info.
For device power management. See Documentation/power/devices.txt for details.
Provide callbacks that are executed during system suspend, hibernation, system resume and during runtime PM transitions along with subsystem-level and driver-level callbacks.
For device pin management. See Documentation/pinctrl.txt for details.
NUMA node this device is close to.
Dma mask (if dma'ble device).
Like dma_mask, but for alloc_coherent mapping as not all hardware supports 64-bit addresses for consistent allocations such descriptors.
offset of DMA memory range relatively of RAM
A low level driver may set these to teach IOMMU code about segment limitations.
Dma pools (if dma'ble device).
Internal for coherent mem override.
Contiguous memory area for dma allocations
For arch-specific additions.
Associated device tree node.
Associated device node supplied by platform firmware.
For creating the sysfs “dev”.
device instance
Spinlock to protect the resource of the device.
The resources list of the device.
The node used to add the device to the class list.
The class of the device.
Optional attribute groups.
Callback to free the device after all references have gone away. This should be set by the allocator of the device (i.e. the bus driver that discovered the device).
IOMMU group the device belongs to.
If set, the device is permanently online.
Set after successful invocation of bus type's .offline.
For devices on custom boards, as typical of embedded
and SOC based hardware, Linux often uses platform_data to point
to board-specific structures describing devices and how they
are wired. That can include what ports are available, chip
variants, which GPIO pins act in what additional roles, and so
on. This shrinks the “Board Support Packages” (BSPs) and
minimizes board-specific #ifdefs in drivers.
At the lowest level, every device in a Linux system is represented by an instance of struct device. The device structure contains the information that the device model core needs to model the system. Most subsystems, however, track additional information about the devices they host. As a result, it is rare for devices to be represented by bare device structures; instead, that structure, like kobject structures, is usually embedded within a higher-level representation of the device.