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/notifier.h>
  20 #include <linux/mfd/cros_ec_commands.h>
  21 #include <linux/mutex.h>
  22
  23 /*
  24  * Command interface between EC and AP, for LPC, I2C and SPI interfaces.
  25  */
  26 enum {
  27         EC_MSG_TX_HEADER_BYTES  = 3,
  28         EC_MSG_TX_TRAILER_BYTES = 1,
  29         EC_MSG_TX_PROTO_BYTES   = EC_MSG_TX_HEADER_BYTES +
  30                                         EC_MSG_TX_TRAILER_BYTES,
  31         EC_MSG_RX_PROTO_BYTES   = 3,
  32
  33         /* Max length of messages */
  34         EC_MSG_BYTES            = EC_PROTO2_MAX_PARAM_SIZE +
  35                                         EC_MSG_TX_PROTO_BYTES,
  36 };
  37
  38 /*
  39  * @version: Command version number (often 0)
  40  * @command: Command to send (EC_CMD_...)
  41  * @outdata: Outgoing data to EC
  42  * @outsize: Outgoing length in bytes
  43  * @indata: Where to put the incoming data from EC
  44  * @insize: Max number of bytes to accept from EC
  45  * @result: EC's response to the command (separate from communication failure)
  46  */
  47 struct cros_ec_command {
  48         uint32_t version;
  49         uint32_t command;
  50         uint8_t *outdata;
  51         uint32_t outsize;
  52         uint8_t *indata;
  53         uint32_t insize;
  54         uint32_t result;
  55 };
  56
  57 /**
  58  * struct cros_ec_device - Information about a ChromeOS EC device
  59  *
  60  * @ec_name: name of EC device (e.g. 'chromeos-ec')
  61  * @phys_name: name of physical comms layer (e.g. 'i2c-4')
  62  * @dev: Device pointer
  63  * @was_wake_device: true if this device was set to wake the system from
  64  * sleep at the last suspend
  65  *
  66  * @priv: Private data
  67  * @irq: Interrupt to use
  68  * @din: input buffer (for data from EC)
  69  * @dout: output buffer (for data to EC)
  70  * \note
  71  * These two buffers will always be dword-aligned and include enough
  72  * space for up to 7 word-alignment bytes also, so we can ensure that
  73  * the body of the message is always dword-aligned (64-bit).
  74  * We use this alignment to keep ARM and x86 happy. Probably word
  75  * alignment would be OK, there might be a small performance advantage
  76  * to using dword.
  77  * @din_size: size of din buffer to allocate (zero to use static din)
  78  * @dout_size: size of dout buffer to allocate (zero to use static dout)
  79  * @parent: pointer to parent device (e.g. i2c or spi device)
  80  * @wake_enabled: true if this device can wake the system from sleep
  81  * @cmd_xfer: send command to EC and get response
  82  *     Returns the number of bytes received if the communication succeeded, but
  83  *     that doesn't mean the EC was happy with the command. The caller
  84  *     should check msg.result for the EC's result code.
  85  * @lock: one transaction at a time
  86  */
  87 struct cros_ec_device {
  88
  89         /* These are used by other drivers that want to talk to the EC */
  90         const char *ec_name;
  91         const char *phys_name;
  92         struct device *dev;
  93         bool was_wake_device;
  94         struct class *cros_class;
  95
  96         /* These are used to implement the platform-specific interface */
  97         void *priv;
  98         int irq;
  99         uint8_t *din;
 100         uint8_t *dout;
 101         int din_size;
 102         int dout_size;
 103         struct device *parent;
 104         bool wake_enabled;
 105         int (*cmd_xfer)(struct cros_ec_device *ec,
 106                         struct cros_ec_command *msg);
 107         struct mutex lock;
 108 };
 109
 110 /**
 111  * cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
 112  *
 113  * This can be called by drivers to handle a suspend event.
 114  *
 115  * ec_dev: Device to suspend
 116  * @return 0 if ok, -ve on error
 117  */
 118 int cros_ec_suspend(struct cros_ec_device *ec_dev);
 119
 120 /**
 121  * cros_ec_resume - Handle a resume operation for the ChromeOS EC device
 122  *
 123  * This can be called by drivers to handle a resume event.
 124  *
 125  * @ec_dev: Device to resume
 126  * @return 0 if ok, -ve on error
 127  */
 128 int cros_ec_resume(struct cros_ec_device *ec_dev);
 129
 130 /**
 131  * cros_ec_prepare_tx - Prepare an outgoing message in the output buffer
 132  *
 133  * This is intended to be used by all ChromeOS EC drivers, but at present
 134  * only SPI uses it. Once LPC uses the same protocol it can start using it.
 135  * I2C could use it now, with a refactor of the existing code.
 136  *
 137  * @ec_dev: Device to register
 138  * @msg: Message to write
 139  */
 140 int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
 141                        struct cros_ec_command *msg);
 142
 143 /**
 144  * cros_ec_check_result - Check ec_msg->result
 145  *
 146  * This is used by ChromeOS EC drivers to check the ec_msg->result for
 147  * errors and to warn about them.
 148  *
 149  * @ec_dev: EC device
 150  * @msg: Message to check
 151  */
 152 int cros_ec_check_result(struct cros_ec_device *ec_dev,
 153                          struct cros_ec_command *msg);
 154
 155 /**
 156  * cros_ec_cmd_xfer - Send a command to the ChromeOS EC
 157  *
 158  * Call this to send a command to the ChromeOS EC.  This should be used
 159  * instead of calling the EC's cmd_xfer() callback directly.
 160  *
 161  * @ec_dev: EC device
 162  * @msg: Message to write
 163  */
 164 int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
 165                      struct cros_ec_command *msg);
 166
 167 /**
 168  * cros_ec_remove - Remove a ChromeOS EC
 169  *
 170  * Call this to deregister a ChromeOS EC, then clean up any private data.
 171  *
 172  * @ec_dev: Device to register
 173  * @return 0 if ok, -ve on error
 174  */
 175 int cros_ec_remove(struct cros_ec_device *ec_dev);
 176
 177 /**
 178  * cros_ec_register - Register a new ChromeOS EC, using the provided info
 179  *
 180  * Before calling this, allocate a pointer to a new device and then fill
 181  * in all the fields up to the --private-- marker.
 182  *
 183  * @ec_dev: Device to register
 184  * @return 0 if ok, -ve on error
 185  */
 186 int cros_ec_register(struct cros_ec_device *ec_dev);
 187
 188 #endif /* __LINUX_MFD_CROS_EC_H */