1 /* 2 * ChromeOS EC multi-function device 3 * 4 * Copyright (C) 2012 Google, Inc 5 * 6 * This software is licensed under the terms of the GNU General Public 7 * License version 2, as published by the Free Software Foundation, and 8 * may be copied, distributed, and modified under those terms. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 #ifndef __LINUX_MFD_CROS_EC_H 17 #define __LINUX_MFD_CROS_EC_H 18 19 #include <linux/cdev.h> 20 #include <linux/device.h> 21 #include <linux/notifier.h> 22 #include <linux/mfd/cros_ec_commands.h> 23 #include <linux/mutex.h> 24 25 #define CROS_EC_DEV_NAME "cros_ec" 26 #define CROS_EC_DEV_PD_NAME "cros_pd" 27 28 /* 29 * The EC is unresponsive for a time after a reboot command. Add a 30 * simple delay to make sure that the bus stays locked. 31 */ 32 #define EC_REBOOT_DELAY_MS 50 33 34 /* 35 * Max bus-specific overhead incurred by request/responses. 36 * I2C requires 1 additional byte for requests. 37 * I2C requires 2 additional bytes for responses. 38 * */ 39 #define EC_PROTO_VERSION_UNKNOWN 0 40 #define EC_MAX_REQUEST_OVERHEAD 1 41 #define EC_MAX_RESPONSE_OVERHEAD 2 42 43 /* 44 * Command interface between EC and AP, for LPC, I2C and SPI interfaces. 45 */ 46 enum { 47 EC_MSG_TX_HEADER_BYTES = 3, 48 EC_MSG_TX_TRAILER_BYTES = 1, 49 EC_MSG_TX_PROTO_BYTES = EC_MSG_TX_HEADER_BYTES + 50 EC_MSG_TX_TRAILER_BYTES, 51 EC_MSG_RX_PROTO_BYTES = 3, 52 53 /* Max length of messages */ 54 EC_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE + 55 EC_MSG_TX_PROTO_BYTES, 56 }; 57 58 /* 59 * @version: Command version number (often 0) 60 * @command: Command to send (EC_CMD_...) 61 * @outsize: Outgoing length in bytes 62 * @insize: Max number of bytes to accept from EC 63 * @result: EC's response to the command (separate from communication failure) 64 * @data: Where to put the incoming data from EC and outgoing data to EC 65 */ 66 struct cros_ec_command { 67 uint32_t version; 68 uint32_t command; 69 uint32_t outsize; 70 uint32_t insize; 71 uint32_t result; 72 uint8_t data[0]; 73 }; 74 75 /** 76 * struct cros_ec_device - Information about a ChromeOS EC device 77 * 78 * @phys_name: name of physical comms layer (e.g. 'i2c-4') 79 * @dev: Device pointer for physical comms device 80 * @was_wake_device: true if this device was set to wake the system from 81 * sleep at the last suspend 82 * @cmd_readmem: direct read of the EC memory-mapped region, if supported 83 * @offset is within EC_LPC_ADDR_MEMMAP region. 84 * @bytes: number of bytes to read. zero means "read a string" (including 85 * the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be read. 86 * Caller must ensure that the buffer is large enough for the result when 87 * reading a string. 88 * 89 * @priv: Private data 90 * @irq: Interrupt to use 91 * @id: Device id 92 * @din: input buffer (for data from EC) 93 * @dout: output buffer (for data to EC) 94 * \note 95 * These two buffers will always be dword-aligned and include enough 96 * space for up to 7 word-alignment bytes also, so we can ensure that 97 * the body of the message is always dword-aligned (64-bit). 98 * We use this alignment to keep ARM and x86 happy. Probably word 99 * alignment would be OK, there might be a small performance advantage 100 * to using dword. 101 * @din_size: size of din buffer to allocate (zero to use static din) 102 * @dout_size: size of dout buffer to allocate (zero to use static dout) 103 * @wake_enabled: true if this device can wake the system from sleep 104 * @cmd_xfer: send command to EC and get response 105 * Returns the number of bytes received if the communication succeeded, but 106 * that doesn't mean the EC was happy with the command. The caller 107 * should check msg.result for the EC's result code. 108 * @pkt_xfer: send packet to EC and get response 109 * @lock: one transaction at a time 110 */ 111 struct cros_ec_device { 112 113 /* These are used by other drivers that want to talk to the EC */ 114 const char *phys_name; 115 struct device *dev; 116 bool was_wake_device; 117 struct class *cros_class; 118 int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset, 119 unsigned int bytes, void *dest); 120 121 /* These are used to implement the platform-specific interface */ 122 u16 max_request; 123 u16 max_response; 124 u16 max_passthru; 125 u16 proto_version; 126 void *priv; 127 int irq; 128 u8 *din; 129 u8 *dout; 130 int din_size; 131 int dout_size; 132 bool wake_enabled; 133 int (*cmd_xfer)(struct cros_ec_device *ec, 134 struct cros_ec_command *msg); 135 int (*pkt_xfer)(struct cros_ec_device *ec, 136 struct cros_ec_command *msg); 137 struct mutex lock; 138 }; 139 140 /* struct cros_ec_platform - ChromeOS EC platform information 141 * 142 * @ec_name: name of EC device (e.g. 'cros-ec', 'cros-pd', ...) 143 * used in /dev/ and sysfs. 144 * @cmd_offset: offset to apply for each command. Set when 145 * registering a devicde behind another one. 146 */ 147 struct cros_ec_platform { 148 const char *ec_name; 149 u16 cmd_offset; 150 }; 151 152 /* 153 * struct cros_ec_dev - ChromeOS EC device entry point 154 * 155 * @class_dev: Device structure used in sysfs 156 * @cdev: Character device structure in /dev 157 * @ec_dev: cros_ec_device structure to talk to the physical device 158 * @dev: pointer to the platform device 159 * @cmd_offset: offset to apply for each command. 160 */ 161 struct cros_ec_dev { 162 struct device class_dev; 163 struct cdev cdev; 164 struct cros_ec_device *ec_dev; 165 struct device *dev; 166 u16 cmd_offset; 167 }; 168 169 /** 170 * cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device 171 * 172 * This can be called by drivers to handle a suspend event. 173 * 174 * ec_dev: Device to suspend 175 * @return 0 if ok, -ve on error 176 */ 177 int cros_ec_suspend(struct cros_ec_device *ec_dev); 178 179 /** 180 * cros_ec_resume - Handle a resume operation for the ChromeOS EC device 181 * 182 * This can be called by drivers to handle a resume event. 183 * 184 * @ec_dev: Device to resume 185 * @return 0 if ok, -ve on error 186 */ 187 int cros_ec_resume(struct cros_ec_device *ec_dev); 188 189 /** 190 * cros_ec_prepare_tx - Prepare an outgoing message in the output buffer 191 * 192 * This is intended to be used by all ChromeOS EC drivers, but at present 193 * only SPI uses it. Once LPC uses the same protocol it can start using it. 194 * I2C could use it now, with a refactor of the existing code. 195 * 196 * @ec_dev: Device to register 197 * @msg: Message to write 198 */ 199 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev, 200 struct cros_ec_command *msg); 201 202 /** 203 * cros_ec_check_result - Check ec_msg->result 204 * 205 * This is used by ChromeOS EC drivers to check the ec_msg->result for 206 * errors and to warn about them. 207 * 208 * @ec_dev: EC device 209 * @msg: Message to check 210 */ 211 int cros_ec_check_result(struct cros_ec_device *ec_dev, 212 struct cros_ec_command *msg); 213 214 /** 215 * cros_ec_cmd_xfer - Send a command to the ChromeOS EC 216 * 217 * Call this to send a command to the ChromeOS EC. This should be used 218 * instead of calling the EC's cmd_xfer() callback directly. 219 * 220 * @ec_dev: EC device 221 * @msg: Message to write 222 */ 223 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, 224 struct cros_ec_command *msg); 225 226 /** 227 * cros_ec_remove - Remove a ChromeOS EC 228 * 229 * Call this to deregister a ChromeOS EC, then clean up any private data. 230 * 231 * @ec_dev: Device to register 232 * @return 0 if ok, -ve on error 233 */ 234 int cros_ec_remove(struct cros_ec_device *ec_dev); 235 236 /** 237 * cros_ec_register - Register a new ChromeOS EC, using the provided info 238 * 239 * Before calling this, allocate a pointer to a new device and then fill 240 * in all the fields up to the --private-- marker. 241 * 242 * @ec_dev: Device to register 243 * @return 0 if ok, -ve on error 244 */ 245 int cros_ec_register(struct cros_ec_device *ec_dev); 246 247 /** 248 * cros_ec_register - Query the protocol version supported by the ChromeOS EC 249 * 250 * @ec_dev: Device to register 251 * @return 0 if ok, -ve on error 252 */ 253 int cros_ec_query_all(struct cros_ec_device *ec_dev); 254 255 /* sysfs stuff */ 256 extern struct attribute_group cros_ec_attr_group; 257 extern struct attribute_group cros_ec_lightbar_attr_group; 258 extern struct attribute_group cros_ec_vbc_attr_group; 259 260 #endif /* __LINUX_MFD_CROS_EC_H */ 261