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* This file is part of the coreboot project.
* Copyright (C) 2014 Google, Inc.
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* GNU General Public License for more details.
#ifndef _DEVICE_I2C_H_
#define _DEVICE_I2C_H_
#include <stdint.h>
* struct i2c_msg - an I2C transaction segment beginning with START
* @addr: Slave address, either seven or ten bits. When this is a ten
* bit address, I2C_M_TEN must be set in @flags.
* @flags: I2C_M_RD is handled by all adapters.
* @len: Number of data bytes in @buf being read from or written to the
* I2C slave address. For read transactions where I2C_M_RECV_LEN
* is set, the caller guarantees that this buffer can hold up to
* 32 bytes in addition to the initial length byte sent by the
* slave (plus, if used, the SMBus PEC).
* @buf: The buffer into which data is read, or from which it's written.
* An i2c_msg is the low level representation of one segment of an I2C
* transaction. It is visible to drivers in the @i2c_transfer() procedure.
* All I2C adapters implement the standard rules for I2C transactions. Each
* transaction begins with a START. That is followed by the slave address,
* and a bit encoding read versus write. Then follow all the data bytes,
* possibly including a byte with SMBus PEC. The transfer terminates with
* a NAK, or when all those bytes have been transferred and ACKed. If this
* is the last message in a group, it is followed by a STOP. Otherwise it
* is followed by the next @i2c_msg transaction segment, beginning with a
* (repeated) START.
struct i2c_msg {
uint16_t flags;
#define I2C_M_RD 0x0001 /* read data, from slave to master */
#define I2C_M_TEN 0x0010 /* this is a ten bit chip address */
#define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */
#define I2C_M_NOSTART 0x4000 /* don't send a repeated START */
uint16_t slave; /* slave address */
uint16_t len; /* msg length */
uint8_t *buf; /* pointer to msg data */
enum i2c_speed {
I2C_SPEED_FAST = 400000,
I2C_SPEED_FAST_PLUS = 1000000,
I2C_SPEED_HIGH = 3400000,
enum i2c_address_mode {
#endif /* _DEVICE_I2C_H_ */