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 */
  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 */