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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
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#ifndef _DEVICE_I2C_H_
#define _DEVICE_I2C_H_
#include <stdint.h>
#include <stdlib.h>
struct i2c_seg
{
int read;
uint8_t chip;
uint8_t *buf;
int len;
};
int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count);
#define SOFTWARE_I2C_MAX_BUS 10 /* increase as necessary */
struct software_i2c_ops {
void (*set_sda)(unsigned bus, int high);
void (*set_scl)(unsigned bus, int high);
int (*get_sda)(unsigned bus);
int (*get_scl)(unsigned bus);
};
extern struct software_i2c_ops *software_i2c[];
int software_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count);
void software_i2c_wedge_ack(unsigned bus, u8 chip);
void software_i2c_wedge_read(unsigned bus, u8 chip, u8 reg, int bit_count);
void software_i2c_wedge_write(unsigned bus, u8 chip, u8 reg, int bit_count);
/*
* software_i2c is supposed to be a debug feature. It's usually not compiled in,
* but when it is it can be dynamically enabled at runtime for certain busses.
* Need this ugly stub to arbitrate since I2C device drivers hardcode
* 'i2c_transfer()' as their entry point.
*/
static inline int i2c_transfer(unsigned bus, struct i2c_seg *segments,
int count)
{
if (CONFIG_SOFTWARE_I2C)
if (bus < SOFTWARE_I2C_MAX_BUS && software_i2c[bus])
return software_i2c_transfer(bus, segments, count);
return platform_i2c_transfer(bus, segments, count);
}
/*
* Read a raw chunk of data in one segment and one frame.
*
* [start][slave addr][r][data][stop]
*/
static inline int i2c_read_raw(unsigned bus, uint8_t chip, uint8_t *data,
int len)
{
struct i2c_seg seg =
{ .read = 1, .chip = chip, .buf = data, .len = len };
return i2c_transfer(bus, &seg, 1);
}
/*
* Write a raw chunk of data in one segment and one frame.
*
* [start][slave addr][w][data][stop]
*/
static inline int i2c_write_raw(unsigned bus, uint8_t chip, uint8_t *data,
int len)
{
struct i2c_seg seg =
{ .read = 0, .chip = chip, .buf = data, .len = len };
return i2c_transfer(bus, &seg, 1);
}
/**
* Read multi-bytes with two segments in one frame
*
* [start][slave addr][w][register addr][start][slave addr][r][data...][stop]
*/
static inline int i2c_read_bytes(unsigned bus, uint8_t chip, uint8_t reg,
uint8_t *data, int len)
{
struct i2c_seg seg[2];
seg[0].read = 0;
seg[0].chip = chip;
seg[0].buf = ®
seg[0].len = 1;
seg[1].read = 1;
seg[1].chip = chip;
seg[1].buf = data;
seg[1].len = len;
return i2c_transfer(bus, seg, ARRAY_SIZE(seg));
}
/**
* Read a byte with two segments in one frame
*
* [start][slave addr][w][register addr][start][slave addr][r][data][stop]
*/
static inline int i2c_readb(unsigned bus, uint8_t chip, uint8_t reg,
uint8_t *data)
{
struct i2c_seg seg[2];
seg[0].read = 0;
seg[0].chip = chip;
seg[0].buf = ®
seg[0].len = 1;
seg[1].read = 1;
seg[1].chip = chip;
seg[1].buf = data;
seg[1].len = 1;
return i2c_transfer(bus, seg, ARRAY_SIZE(seg));
}
/**
* Write a byte with one segment in one frame.
*
* [start][slave addr][w][register addr][data][stop]
*/
static inline int i2c_writeb(unsigned bus, uint8_t chip, uint8_t reg,
uint8_t data)
{
struct i2c_seg seg;
uint8_t buf[] = {reg, data};
seg.read = 0;
seg.chip = chip;
seg.buf = buf;
seg.len = ARRAY_SIZE(buf);
return i2c_transfer(bus, &seg, 1);
}
#endif /* _DEVICE_I2C_H_ */
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