include/linux/mfd/cros_ec.h

   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 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  */
  68 struct 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  */
 113 struct 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  */
 149 struct 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  */
 163 struct 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  */
 179 int 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  */
 189 int 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  */
 201 int 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  */
 213 int 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  */
 225 int 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  */
 240 int 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  */
 251 int 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  */
 262 int 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  */
 270 int cros_ec_query_all(struct cros_ec_device *ec_dev);
 271
 272 /* sysfs stuff */
 273 extern struct attribute_group cros_ec_attr_group;
 274 extern struct attribute_group cros_ec_lightbar_attr_group;
 275 extern struct attribute_group cros_ec_vbc_attr_group;
 276
 277 #endif /* __LINUX_MFD_CROS_EC_H */