blob: 5c191f92e18610a7153649251d55b9c98880d534 [file] [log] [blame]
Shiyu Sundc2c83b2020-03-19 16:59:52 +11001/*
2 * This file is part of the flashrom project.
3 *
4 * Copyright (C) 2020 The Chromium OS Authors
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 */
16
17#include <errno.h>
18#include <stdio.h>
19#include <string.h>
Evgeny Zinovievd870a352020-12-05 03:33:44 +030020#include <fcntl.h>
Shiyu Sundc2c83b2020-03-19 16:59:52 +110021#include <sys/ioctl.h>
22#include <unistd.h>
23
24#include <stdlib.h>
25#include <linux/i2c.h>
26#include <linux/i2c-dev.h>
27
28#include "flash.h"
29#include "i2c_helper.h"
30
31#define I2C_DEV_PREFIX "/dev/i2c-"
32#define I2C_MAX_BUS 255
33
34int i2c_close(int fd)
35{
36 return fd == -1 ? 0 : close(fd);
37}
38
39int i2c_open(int bus, uint16_t addr, int force)
40{
41 int ret = -1;
42 int fd = -1;
43
44 /* Maximum i2c bus number is 255(3 char), +1 for null terminated string. */
45 int path_len = strlen(I2C_DEV_PREFIX) + 4;
46 int request = force ? I2C_SLAVE_FORCE : I2C_SLAVE;
47
48 if (bus < 0 || bus > I2C_MAX_BUS) {
49 msg_perr("Invalid I2C bus %d.\n", bus);
50 return ret;
51 }
52
53 char *dev = calloc(1, path_len);
54 if (!dev) {
55 msg_perr("Unable to allocate space for device name of len %d: %s.\n",
56 path_len, strerror(errno));
57 goto linux_i2c_open_err;
58 }
59
60 ret = snprintf(dev, path_len, "%s%d", I2C_DEV_PREFIX, bus);
61 if (ret < 0) {
62 msg_perr("Unable to join bus number to device name: %s.\n", strerror(errno));
63 goto linux_i2c_open_err;
64 }
65
66 fd = open(dev, O_RDWR);
67 if (fd < 0) {
68 msg_perr("Unable to open I2C device %s: %s.\n", dev, strerror(errno));
69 ret = fd;
70 goto linux_i2c_open_err;
71 }
72
73 ret = ioctl(fd, request, addr);
74 if (ret < 0) {
75 msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
76 i2c_close(fd);
77 goto linux_i2c_open_err;
78 }
79
80linux_i2c_open_err:
81 if (dev)
82 free(dev);
83
84 return ret ? ret : fd;
85}
86
87int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf)
88{
89 if (buf->len == 0)
90 return 0;
91
92 int ret = ioctl(fd, I2C_SLAVE, addr);
93 if (ret < 0) {
94 msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
95 return ret;
96 }
97
98 return read(fd, buf->buf, buf->len);
99}
100
101int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf)
102{
103 if (buf->len == 0)
104 return 0;
105
106 int ret = ioctl(fd, I2C_SLAVE, addr);
107 if (ret < 0) {
108 msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
109 return ret;
110 }
111
112 return write(fd, buf->buf, buf->len);
113}