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 */ 46enum { 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 for proto 2*/ 54 EC_PROTO2_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE + 55 EC_MSG_TX_PROTO_BYTES, 56 57 EC_MAX_MSG_BYTES = 64 * 1024, 58}; 59 60/* 61 * @version: Command version number (often 0) 62 * @command: Command to send (EC_CMD_...) 63 * @outsize: Outgoing length in bytes 64 * @insize: Max number of bytes to accept from EC 65 * @result: EC's response to the command (separate from communication failure) 66 * @data: Where to put the incoming data from EC and outgoing data to EC 67 */ 68struct cros_ec_command { 69 uint32_t version; 70 uint32_t command; 71 uint32_t outsize; 72 uint32_t insize; 73 uint32_t result; 74 uint8_t data[0]; 75}; 76 77/** 78 * struct cros_ec_device - Information about a ChromeOS EC device 79 * 80 * @phys_name: name of physical comms layer (e.g. 'i2c-4') 81 * @dev: Device pointer for physical comms device 82 * @was_wake_device: true if this device was set to wake the system from 83 * sleep at the last suspend 84 * @cmd_readmem: direct read of the EC memory-mapped region, if supported 85 * @offset is within EC_LPC_ADDR_MEMMAP region. 86 * @bytes: number of bytes to read. zero means "read a string" (including 87 * the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be read. 88 * Caller must ensure that the buffer is large enough for the result when 89 * reading a string. 90 * 91 * @priv: Private data 92 * @irq: Interrupt to use 93 * @id: Device id 94 * @din: input buffer (for data from EC) 95 * @dout: output buffer (for data to EC) 96 * \note 97 * These two buffers will always be dword-aligned and include enough 98 * space for up to 7 word-alignment bytes also, so we can ensure that 99 * the body of the message is always dword-aligned (64-bit). 100 * We use this alignment to keep ARM and x86 happy. Probably word 101 * alignment would be OK, there might be a small performance advantage 102 * to using dword. 103 * @din_size: size of din buffer to allocate (zero to use static din) 104 * @dout_size: size of dout buffer to allocate (zero to use static dout) 105 * @wake_enabled: true if this device can wake the system from sleep 106 * @cmd_xfer: send command to EC and get response 107 * Returns the number of bytes received if the communication succeeded, but 108 * that doesn't mean the EC was happy with the command. The caller 109 * should check msg.result for the EC's result code. 110 * @pkt_xfer: send packet to EC and get response 111 * @lock: one transaction at a time 112 */ 113struct cros_ec_device { 114 115 /* These are used by other drivers that want to talk to the EC */ 116 const char *phys_name; 117 struct device *dev; 118 bool was_wake_device; 119 struct class *cros_class; 120 int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset, 121 unsigned int bytes, void *dest); 122 123 /* These are used to implement the platform-specific interface */ 124 u16 max_request; 125 u16 max_response; 126 u16 max_passthru; 127 u16 proto_version; 128 void *priv; 129 int irq; 130 u8 *din; 131 u8 *dout; 132 int din_size; 133 int dout_size; 134 bool wake_enabled; 135 int (*cmd_xfer)(struct cros_ec_device *ec, 136 struct cros_ec_command *msg); 137 int (*pkt_xfer)(struct cros_ec_device *ec, 138 struct cros_ec_command *msg); 139 struct mutex lock; 140}; 141 142/* struct cros_ec_platform - ChromeOS EC platform information 143 * 144 * @ec_name: name of EC device (e.g. 'cros-ec', 'cros-pd', ...) 145 * used in /dev/ and sysfs. 146 * @cmd_offset: offset to apply for each command. Set when 147 * registering a devicde behind another one. 148 */ 149struct cros_ec_platform { 150 const char *ec_name; 151 u16 cmd_offset; 152}; 153 154/* 155 * struct cros_ec_dev - ChromeOS EC device entry point 156 * 157 * @class_dev: Device structure used in sysfs 158 * @cdev: Character device structure in /dev 159 * @ec_dev: cros_ec_device structure to talk to the physical device 160 * @dev: pointer to the platform device 161 * @cmd_offset: offset to apply for each command. 162 */ 163struct cros_ec_dev { 164 struct device class_dev; 165 struct cdev cdev; 166 struct cros_ec_device *ec_dev; 167 struct device *dev; 168 u16 cmd_offset; 169}; 170 171/** 172 * cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device 173 * 174 * This can be called by drivers to handle a suspend event. 175 * 176 * ec_dev: Device to suspend 177 * @return 0 if ok, -ve on error 178 */ 179int cros_ec_suspend(struct cros_ec_device *ec_dev); 180 181/** 182 * cros_ec_resume - Handle a resume operation for the ChromeOS EC device 183 * 184 * This can be called by drivers to handle a resume event. 185 * 186 * @ec_dev: Device to resume 187 * @return 0 if ok, -ve on error 188 */ 189int cros_ec_resume(struct cros_ec_device *ec_dev); 190 191/** 192 * cros_ec_prepare_tx - Prepare an outgoing message in the output buffer 193 * 194 * This is intended to be used by all ChromeOS EC drivers, but at present 195 * only SPI uses it. Once LPC uses the same protocol it can start using it. 196 * I2C could use it now, with a refactor of the existing code. 197 * 198 * @ec_dev: Device to register 199 * @msg: Message to write 200 */ 201int cros_ec_prepare_tx(struct cros_ec_device *ec_dev, 202 struct cros_ec_command *msg); 203 204/** 205 * cros_ec_check_result - Check ec_msg->result 206 * 207 * This is used by ChromeOS EC drivers to check the ec_msg->result for 208 * errors and to warn about them. 209 * 210 * @ec_dev: EC device 211 * @msg: Message to check 212 */ 213int cros_ec_check_result(struct cros_ec_device *ec_dev, 214 struct cros_ec_command *msg); 215 216/** 217 * cros_ec_cmd_xfer - Send a command to the ChromeOS EC 218 * 219 * Call this to send a command to the ChromeOS EC. This should be used 220 * instead of calling the EC's cmd_xfer() callback directly. 221 * 222 * @ec_dev: EC device 223 * @msg: Message to write 224 */ 225int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev, 226 struct cros_ec_command *msg); 227 228/** 229 * cros_ec_cmd_xfer_status - Send a command to the ChromeOS EC 230 * 231 * This function is identical to cros_ec_cmd_xfer, except it returns success 232 * status only if both the command was transmitted successfully and the EC 233 * replied with success status. It's not necessary to check msg->result when 234 * using this function. 235 * 236 * @ec_dev: EC device 237 * @msg: Message to write 238 * @return: Num. of bytes transferred on success, <0 on failure 239 */ 240int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev, 241 struct cros_ec_command *msg); 242 243/** 244 * cros_ec_remove - Remove a ChromeOS EC 245 * 246 * Call this to deregister a ChromeOS EC, then clean up any private data. 247 * 248 * @ec_dev: Device to register 249 * @return 0 if ok, -ve on error 250 */ 251int cros_ec_remove(struct cros_ec_device *ec_dev); 252 253/** 254 * cros_ec_register - Register a new ChromeOS EC, using the provided info 255 * 256 * Before calling this, allocate a pointer to a new device and then fill 257 * in all the fields up to the --private-- marker. 258 * 259 * @ec_dev: Device to register 260 * @return 0 if ok, -ve on error 261 */ 262int cros_ec_register(struct cros_ec_device *ec_dev); 263 264/** 265 * cros_ec_query_all - Query the protocol version supported by the ChromeOS EC 266 * 267 * @ec_dev: Device to register 268 * @return 0 if ok, -ve on error 269 */ 270int cros_ec_query_all(struct cros_ec_device *ec_dev); 271 272/* sysfs stuff */ 273extern struct attribute_group cros_ec_attr_group; 274extern struct attribute_group cros_ec_lightbar_attr_group; 275extern struct attribute_group cros_ec_vbc_attr_group; 276 277#endif /* __LINUX_MFD_CROS_EC_H */ 278