/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/* I2C interface for Chrome EC */

#ifndef __CROS_EC_I2C_H
#define __CROS_EC_I2C_H

#include "common.h"

/* Flags for slave address field, in addition to the 8-bit address */
#define I2C_FLAG_BIG_ENDIAN 0x100  /* 16 byte values are MSB-first */

/* Data structure to define I2C port configuration. */
struct i2c_port_t {
	const char *name;  /* Port name */
	int port;          /* Port */
	int kbps;          /* Speed in kbps */
};

/* Read a 16-bit register from the slave at 8-bit slave address <slaveaddr>, at
 * the specified 8-bit <offset> in the slave's address space. */
int i2c_read16(int port, int slave_addr, int offset, int* data);

/* Write a 16-bit register to the slave at 8-bit slave address <slaveaddr>, at
 * the specified 8-bit <offset> in the slave's address space. */
int i2c_write16(int port, int slave_addr, int offset, int data);

/* Read an 8-bit register from the slave at 8-bit slave address <slaveaddr>, at
 * the specified 8-bit <offset> in the slave's address space. */
int i2c_read8(int port, int slave_addr, int offset, int* data);

/* Write an 8-bit register to the slave at 8-bit slave address <slaveaddr>, at
 * the specified 8-bit <offset> in the slave's address space. */
int i2c_write8(int port, int slave_addr, int offset, int data);

/* Read ascii string using smbus read block protocol.
 * Read bytestream from <slaveaddr>:<offset> with format:
 *     [length_N] [byte_0] [byte_1] ... [byte_N-1]
 *
 * <len>      : the max length of receving buffer. to read N bytes
 *              ascii, len should be at least N+1 to include the
 *              terminating 0.
 * <len> == 0 : buffer size > 255
 */
int i2c_read_string(int port, int slave_addr, int offset, uint8_t *data,
			int len);

/**
 * Claim an I2C port for use in master mode
 *
 * If this function succeed, then you must later call board_i2c_release()
 * to release the claim.
 *
 * This function may optionally be implemented by a board file. If provided
 * then it should check the port number and arbitrate as needed.
 *
 * This function will not be called to claim an already-claimed port.
 *
 * @param port	Port to claim (0 for first, 1 for second, etc.)
 * @return 0 if claimed successfully, -1 if it is in use
 */
int board_i2c_claim(int port);

/**
 * Release an I2C port (after previously being claimed)
 *
 * This function may optionally be implemented by a board file. If provided
 * then it should check the port number and arbitrate as needed.
 *
 * This function will not be called to release an already-released port.
 *
 * @param port	Port to claim (0 for first, 1 for second, etc.)
 */
void board_i2c_release(int port);

#endif  /* __CROS_EC_I2C_H */