| /* |
| * This file is part of the flashrom project. |
| * |
| * Copyright (C) 2020 The Chromium OS Authors |
| * |
| * 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; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * 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. |
| */ |
| |
| #include <errno.h> |
| #include <stdio.h> |
| #include <string.h> |
| #include <fcntl.h> |
| #include <sys/ioctl.h> |
| #include <unistd.h> |
| |
| #include <stdlib.h> |
| #include <linux/i2c.h> |
| #include <linux/i2c-dev.h> |
| |
| #include "flash.h" |
| #include "i2c_helper.h" |
| |
| #define I2C_DEV_PREFIX "/dev/i2c-" |
| #define I2C_MAX_BUS 255 |
| |
| int i2c_close(int fd) |
| { |
| return fd == -1 ? 0 : close(fd); |
| } |
| |
| int i2c_open(int bus, uint16_t addr, int force) |
| { |
| int ret = -1; |
| int fd = -1; |
| |
| /* Maximum i2c bus number is 255(3 char), +1 for null terminated string. */ |
| int path_len = strlen(I2C_DEV_PREFIX) + 4; |
| int request = force ? I2C_SLAVE_FORCE : I2C_SLAVE; |
| |
| if (bus < 0 || bus > I2C_MAX_BUS) { |
| msg_perr("Invalid I2C bus %d.\n", bus); |
| return ret; |
| } |
| |
| char *dev = calloc(1, path_len); |
| if (!dev) { |
| msg_perr("Unable to allocate space for device name of len %d: %s.\n", |
| path_len, strerror(errno)); |
| goto linux_i2c_open_err; |
| } |
| |
| ret = snprintf(dev, path_len, "%s%d", I2C_DEV_PREFIX, bus); |
| if (ret < 0) { |
| msg_perr("Unable to join bus number to device name: %s.\n", strerror(errno)); |
| goto linux_i2c_open_err; |
| } |
| |
| fd = open(dev, O_RDWR); |
| if (fd < 0) { |
| msg_perr("Unable to open I2C device %s: %s.\n", dev, strerror(errno)); |
| ret = fd; |
| goto linux_i2c_open_err; |
| } |
| |
| ret = ioctl(fd, request, addr); |
| if (ret < 0) { |
| msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno)); |
| i2c_close(fd); |
| goto linux_i2c_open_err; |
| } |
| |
| linux_i2c_open_err: |
| if (dev) |
| free(dev); |
| |
| return ret ? ret : fd; |
| } |
| |
| int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf) |
| { |
| if (buf->len == 0) |
| return 0; |
| |
| int ret = ioctl(fd, I2C_SLAVE, addr); |
| if (ret < 0) { |
| msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno)); |
| return ret; |
| } |
| |
| return read(fd, buf->buf, buf->len); |
| } |
| |
| int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf) |
| { |
| if (buf->len == 0) |
| return 0; |
| |
| int ret = ioctl(fd, I2C_SLAVE, addr); |
| if (ret < 0) { |
| msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno)); |
| return ret; |
| } |
| |
| return write(fd, buf->buf, buf->len); |
| } |