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/*
* ChromeOS EC multi-function device
*
* Copyright (C) 2012 Google, Inc
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef __LINUX_MFD_CROS_EC_H
#define __LINUX_MFD_CROS_EC_H
#include <linux/cdev.h>
#include <linux/notifier.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/mutex.h>
/*
* Command interface between EC and AP, for LPC, I2C and SPI interfaces.
*/
enum {
EC_MSG_TX_HEADER_BYTES = 3,
EC_MSG_TX_TRAILER_BYTES = 1,
EC_MSG_TX_PROTO_BYTES = EC_MSG_TX_HEADER_BYTES +
EC_MSG_TX_TRAILER_BYTES,
EC_MSG_RX_PROTO_BYTES = 3,
/* Max length of messages */
EC_MSG_BYTES = EC_PROTO2_MAX_PARAM_SIZE +
EC_MSG_TX_PROTO_BYTES,
};
/*
* @version: Command version number (often 0)
* @command: Command to send (EC_CMD_...)
* @outsize: Outgoing length in bytes
* @insize: Max number of bytes to accept from EC
* @result: EC's response to the command (separate from communication failure)
* @data: Where to put the incoming data from EC and outgoing data to EC
*/
struct cros_ec_command {
uint32_t version;
uint32_t command;
uint32_t outsize;
uint32_t insize;
uint32_t result;
uint8_t data[0];
};
/**
* struct cros_ec_device - Information about a ChromeOS EC device
*
* @ec_name: name of EC device (e.g. 'chromeos-ec')
* @phys_name: name of physical comms layer (e.g. 'i2c-4')
* @dev: Device pointer for physical comms device
* @vdev: Device pointer for virtual comms device
* @cdev: Character device structure for virtual comms device
* @was_wake_device: true if this device was set to wake the system from
* sleep at the last suspend
* @cmd_readmem: direct read of the EC memory-mapped region, if supported
* @offset is within EC_LPC_ADDR_MEMMAP region.
* @bytes: number of bytes to read. zero means "read a string" (including
* the trailing '\0'). At most only EC_MEMMAP_SIZE bytes can be read.
* Caller must ensure that the buffer is large enough for the result when
* reading a string.
*
* @priv: Private data
* @irq: Interrupt to use
* @din: input buffer (for data from EC)
* @dout: output buffer (for data to EC)
* \note
* These two buffers will always be dword-aligned and include enough
* space for up to 7 word-alignment bytes also, so we can ensure that
* the body of the message is always dword-aligned (64-bit).
* We use this alignment to keep ARM and x86 happy. Probably word
* alignment would be OK, there might be a small performance advantage
* to using dword.
* @din_size: size of din buffer to allocate (zero to use static din)
* @dout_size: size of dout buffer to allocate (zero to use static dout)
* @wake_enabled: true if this device can wake the system from sleep
* @cmd_xfer: send command to EC and get response
* Returns the number of bytes received if the communication succeeded, but
* that doesn't mean the EC was happy with the command. The caller
* should check msg.result for the EC's result code.
* @lock: one transaction at a time
*/
struct cros_ec_device {
/* These are used by other drivers that want to talk to the EC */
const char *ec_name;
const char *phys_name;
struct device *dev;
struct device *vdev;
struct cdev cdev;
bool was_wake_device;
struct class *cros_class;
int (*cmd_readmem)(struct cros_ec_device *ec, unsigned int offset,
unsigned int bytes, void *dest);
/* These are used to implement the platform-specific interface */
void *priv;
int irq;
uint8_t *din;
uint8_t *dout;
int din_size;
int dout_size;
bool wake_enabled;
int (*cmd_xfer)(struct cros_ec_device *ec,
struct cros_ec_command *msg);
struct mutex lock;
};
/**
* cros_ec_suspend - Handle a suspend operation for the ChromeOS EC device
*
* This can be called by drivers to handle a suspend event.
*
* ec_dev: Device to suspend
* @return 0 if ok, -ve on error
*/
int cros_ec_suspend(struct cros_ec_device *ec_dev);
/**
* cros_ec_resume - Handle a resume operation for the ChromeOS EC device
*
* This can be called by drivers to handle a resume event.
*
* @ec_dev: Device to resume
* @return 0 if ok, -ve on error
*/
int cros_ec_resume(struct cros_ec_device *ec_dev);
/**
* cros_ec_prepare_tx - Prepare an outgoing message in the output buffer
*
* This is intended to be used by all ChromeOS EC drivers, but at present
* only SPI uses it. Once LPC uses the same protocol it can start using it.
* I2C could use it now, with a refactor of the existing code.
*
* @ec_dev: Device to register
* @msg: Message to write
*/
int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg);
/**
* cros_ec_check_result - Check ec_msg->result
*
* This is used by ChromeOS EC drivers to check the ec_msg->result for
* errors and to warn about them.
*
* @ec_dev: EC device
* @msg: Message to check
*/
int cros_ec_check_result(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg);
/**
* cros_ec_cmd_xfer - Send a command to the ChromeOS EC
*
* Call this to send a command to the ChromeOS EC. This should be used
* instead of calling the EC's cmd_xfer() callback directly.
*
* @ec_dev: EC device
* @msg: Message to write
*/
int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg);
/**
* cros_ec_remove - Remove a ChromeOS EC
*
* Call this to deregister a ChromeOS EC, then clean up any private data.
*
* @ec_dev: Device to register
* @return 0 if ok, -ve on error
*/
int cros_ec_remove(struct cros_ec_device *ec_dev);
/**
* cros_ec_register - Register a new ChromeOS EC, using the provided info
*
* Before calling this, allocate a pointer to a new device and then fill
* in all the fields up to the --private-- marker.
*
* @ec_dev: Device to register
* @return 0 if ok, -ve on error
*/
int cros_ec_register(struct cros_ec_device *ec_dev);
#endif /* __LINUX_MFD_CROS_EC_H */
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