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  * SPI requires up to 32 additional bytes for responses.
  39  * */
  40 #define EC_PROTO_VERSION_UNKNOWN        0
  41 #define EC_MAX_REQUEST_OVERHEAD         1
  42 #define EC_MAX_RESPONSE_OVERHEAD        32
  43
  44 /*
  45  * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
  46  */
  47 enum {
  48         EC_MSG_TX_HEADER_BYTES  = 3,
  49         EC_MSG_TX_TRAILER_BYTES = 1,
  50         EC_MSG_TX_PROTO_BYTES   = EC_MSG_TX_HEADER_BYTES +
  51                                         EC_MSG_TX_TRAILER_BYTES,
  52         EC_MSG_RX_PROTO_BYTES   = 3,
  53
  54         /* Max length of messages for proto 2*/
  55         EC_PROTO2_MSG_BYTES             = EC_PROTO2_MAX_PARAM_SIZE +
  56                                         EC_MSG_TX_PROTO_BYTES,
  57
  58         EC_MAX_MSG_BYTES                = 64 * 1024,
  59 };
  60
  61 /*
  62  * @version: Command version number (often 0)
  63  * @command: Command to send (EC_CMD_...)
  64  * @outsize: Outgoing length in bytes
  65  * @insize: Max number of bytes to accept from EC
  66  * @result: EC's response to the command (separate from communication failure)
  67  * @data: Where to put the incoming data from EC and outgoing data to EC
  68  */
  69 struct cros_ec_command {
  70         uint32_t version;
  71         uint32_t command;
  72         uint32_t outsize;
  73         uint32_t insize;
  74         uint32_t result;
  75         uint8_t data[0];
  76 };
  77
  78 /**
  79  * struct cros_ec_device - Information about a ChromeOS EC device
  80  *
  81  * @phys_name: name of physical comms layer (e.g. 'i2c-4')
  82  * @dev: Device pointer for physical comms device
  83  * @was_wake_device: true if this device was set to wake the system from
  84  * sleep at the last suspend
  85  * @cmd_readmem: direct read of the EC memory-mapped region, if supported
  86  *     @offset is within EC_LPC_ADDR_MEMMAP region.
  87  *     @bytes: number of bytes to read. zero means "read a string" (including
  88  *     the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be read.
  89  *     Caller must ensure that the buffer is large enough for the result when
  90  *     reading a string.
  91  *
  92  * @priv: Private data
  93  * @irq: Interrupt to use
  94  * @id: Device id
  95  * @din: input buffer (for data from EC)
  96  * @dout: output buffer (for data to EC)
  97  * \note
  98  * These two buffers will always be dword-aligned and include enough
  99  * space for up to 7 word-alignment bytes also, so we can ensure that
 100  * the body of the message is always dword-aligned (64-bit).
 101  * We use this alignment to keep ARM and x86 happy. Probably word
 102  * alignment would be OK, there might be a small performance advantage
 103  * to using dword.
 104  * @din_size: size of din buffer to allocate (zero to use static din)
 105  * @dout_size: size of dout buffer to allocate (zero to use static dout)
 106  * @wake_enabled: true if this device can wake the system from sleep
 107  * @suspended: true if this device had been suspended
 108  * @cmd_xfer: send command to EC and get response
 109  *     Returns the number of bytes received if the communication succeeded, but
 110  *     that doesn't mean the EC was happy with the command. The caller
 111  *     should check msg.result for the EC's result code.
 112  * @pkt_xfer: send packet to EC and get response
 113  * @lock: one transaction at a time
 114  * @mkbp_event_supported: true if this EC supports the MKBP event protocol.
 115  * @event_notifier: interrupt event notifier for transport devices.
 116  * @event_data: raw payload transferred with the MKBP event.
 117  * @event_size: size in bytes of the event data.
 118  */
 119 struct cros_ec_device {
 120
 121         /* These are used by other drivers that want to talk to the EC */
 122         const char *phys_name;
 123         struct device *dev;
 124         bool was_wake_device;
 125         struct class *cros_class;
 126         int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset,
 127                            unsigned int bytes, void *dest);
 128
 129         /* These are used to implement the platform-specific interface */
 130         u16 max_request;
 131         u16 max_response;
 132         u16 max_passthru;
 133         u16 proto_version;
 134         void *priv;
 135         int irq;
 136         u8 *din;
 137         u8 *dout;
 138         int din_size;
 139         int dout_size;
 140         bool wake_enabled;
 141         bool suspended;
 142         int (*cmd_xfer)(struct cros_ec_device *ec,
 143                         struct cros_ec_command *msg);
 144         int (*pkt_xfer)(struct cros_ec_device *ec,
 145                         struct cros_ec_command *msg);
 146         struct mutex lock;
 147         bool mkbp_event_supported;
 148         struct blocking_notifier_head event_notifier;
 149
 150         struct ec_response_get_next_event event_data;
 151         int event_size;
 152 };
 153
 154 /**
 155  * struct cros_ec_sensor_platform - ChromeOS EC sensor platform information
 156  *
 157  * @sensor_num: Id of the sensor, as reported by the EC.
 158  */
 159 struct cros_ec_sensor_platform {
 160         u8 sensor_num;
 161 };
 162
 163 /* struct cros_ec_platform - ChromeOS EC platform information
 164  *
 165  * @ec_name: name of EC device (e.g. 'cros-ec', 'cros-pd', ...)
 166  * used in /dev/ and sysfs.
 167  * @cmd_offset: offset to apply for each command. Set when
 168  * registering a devicde behind another one.
 169  */
 170 struct cros_ec_platform {
 171         const char *ec_name;
 172         u16 cmd_offset;
 173 };
 174
 175 /*
 176  * struct cros_ec_dev - ChromeOS EC device entry point
 177  *
 178  * @class_dev: Device structure used in sysfs
 179  * @cdev: Character device structure in /dev
 180  * @ec_dev: cros_ec_device structure to talk to the physical device
 181  * @dev: pointer to the platform device
 182  * @cmd_offset: offset to apply for each command.
 183  */
 184 struct cros_ec_dev {
 185         struct device class_dev;
 186         struct cdev cdev;
 187         struct cros_ec_device *ec_dev;
 188         struct device *dev;
 189         u16 cmd_offset;
 190         u32 features[2];
 191 };
 192
 193 /**
 194  * cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
 195  *
 196  * This can be called by drivers to handle a suspend event.
 197  *
 198  * ec_dev: Device to suspend
 199  * @return 0 if ok, -ve on error
 200  */
 201 int cros_ec_suspend(struct cros_ec_device *ec_dev);
 202
 203 /**
 204  * cros_ec_resume - Handle a resume operation for the ChromeOS EC device
 205  *
 206  * This can be called by drivers to handle a resume event.
 207  *
 208  * @ec_dev: Device to resume
 209  * @return 0 if ok, -ve on error
 210  */
 211 int cros_ec_resume(struct cros_ec_device *ec_dev);
 212
 213 /**
 214  * cros_ec_prepare_tx - Prepare an outgoing message in the output buffer
 215  *
 216  * This is intended to be used by all ChromeOS EC drivers, but at present
 217  * only SPI uses it. Once LPC uses the same protocol it can start using it.
 218  * I2C could use it now, with a refactor of the existing code.
 219  *
 220  * @ec_dev: Device to register
 221  * @msg: Message to write
 222  */
 223 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
 224                        struct cros_ec_command *msg);
 225
 226 /**
 227  * cros_ec_check_result - Check ec_msg->result
 228  *
 229  * This is used by ChromeOS EC drivers to check the ec_msg->result for
 230  * errors and to warn about them.
 231  *
 232  * @ec_dev: EC device
 233  * @msg: Message to check
 234  */
 235 int cros_ec_check_result(struct cros_ec_device *ec_dev,
 236                          struct cros_ec_command *msg);
 237
 238 /**
 239  * cros_ec_cmd_xfer - Send a command to the ChromeOS EC
 240  *
 241  * Call this to send a command to the ChromeOS EC.  This should be used
 242  * instead of calling the EC's cmd_xfer() callback directly.
 243  *
 244  * @ec_dev: EC device
 245  * @msg: Message to write
 246  */
 247 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 248                      struct cros_ec_command *msg);
 249
 250 /**
 251  * cros_ec_cmd_xfer_status - Send a command to the ChromeOS EC
 252  *
 253  * This function is identical to cros_ec_cmd_xfer, except it returns success
 254  * status only if both the command was transmitted successfully and the EC
 255  * replied with success status. It's not necessary to check msg->result when
 256  * using this function.
 257  *
 258  * @ec_dev: EC device
 259  * @msg: Message to write
 260  * @return: Num. of bytes transferred on success, <0 on failure
 261  */
 262 int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
 263                             struct cros_ec_command *msg);
 264
 265 /**
 266  * cros_ec_remove - Remove a ChromeOS EC
 267  *
 268  * Call this to deregister a ChromeOS EC, then clean up any private data.
 269  *
 270  * @ec_dev: Device to register
 271  * @return 0 if ok, -ve on error
 272  */
 273 int cros_ec_remove(struct cros_ec_device *ec_dev);
 274
 275 /**
 276  * cros_ec_register - Register a new ChromeOS EC, using the provided info
 277  *
 278  * Before calling this, allocate a pointer to a new device and then fill
 279  * in all the fields up to the --private-- marker.
 280  *
 281  * @ec_dev: Device to register
 282  * @return 0 if ok, -ve on error
 283  */
 284 int cros_ec_register(struct cros_ec_device *ec_dev);
 285
 286 /**
 287  * cros_ec_query_all -  Query the protocol version supported by the ChromeOS EC
 288  *
 289  * @ec_dev: Device to register
 290  * @return 0 if ok, -ve on error
 291  */
 292 int cros_ec_query_all(struct cros_ec_device *ec_dev);
 293
 294 /**
 295  * cros_ec_get_next_event -  Fetch next event from the ChromeOS EC
 296  *
 297  * @ec_dev: Device to fetch event from
 298  *
 299  * Returns: 0 on success, Linux error number on failure
 300  */
 301 int cros_ec_get_next_event(struct cros_ec_device *ec_dev);
 302
 303 /* sysfs stuff */
 304 extern struct attribute_group cros_ec_attr_group;
 305 extern struct attribute_group cros_ec_lightbar_attr_group;
 306 extern struct attribute_group cros_ec_vbc_attr_group;
 307
 308 /* ACPI GPE handler */
 309 #ifdef CONFIG_ACPI
 310
 311 int cros_ec_acpi_install_gpe_handler(struct device *dev);
 312 void cros_ec_acpi_remove_gpe_handler(void);
 313 void cros_ec_acpi_clear_gpe(void);
 314
 315 #else /* CONFIG_ACPI */
 316
 317 static inline int cros_ec_acpi_install_gpe_handler(struct device *dev)
 318 {
 319         return -ENODEV;
 320 }
 321 static inline void cros_ec_acpi_remove_gpe_handler(void) {}
 322 static inline void cros_ec_acpi_clear_gpe(void) {}
 323
 324 #endif /* CONFIG_ACPI */
 325
 326 #endif /* __LINUX_MFD_CROS_EC_H */