| /* |
| * 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" |
| #include "programmer.h" |
| |
| /* Null characters are placeholders for bus number digits */ |
| #define I2C_DEV_PREFIX "/dev/i2c-\0\0\0" |
| #define I2C_MAX_BUS 255 |
| |
| int i2c_close(int fd) |
| { |
| return fd == -1 ? 0 : close(fd); |
| } |
| |
| int i2c_open_path(const char *path, uint16_t addr, int force) |
| { |
| int fd = open(path, O_RDWR); |
| if (fd < 0) { |
| msg_perr("Unable to open I2C device %s: %s.\n", path, strerror(errno)); |
| return fd; |
| } |
| |
| int request = force ? I2C_SLAVE_FORCE : I2C_SLAVE; |
| int 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); |
| return ret; |
| } |
| |
| return fd; |
| } |
| |
| int i2c_open(int bus, uint16_t addr, int force) |
| { |
| char dev[sizeof(I2C_DEV_PREFIX)] = {0}; |
| |
| int ret = -1; |
| |
| if (bus < 0 || bus > I2C_MAX_BUS) { |
| msg_perr("Invalid I2C bus %d.\n", bus); |
| return ret; |
| } |
| |
| ret = snprintf(dev, sizeof(dev), "%s%d", I2C_DEV_PREFIX, bus); |
| if (ret < 0) { |
| msg_perr("Unable to join bus number to device name: %s.\n", strerror(errno)); |
| return ret; |
| } |
| |
| return i2c_open_path(dev, addr, force); |
| } |
| |
| static int get_bus_number(char *bus_str) |
| { |
| char *bus_suffix; |
| errno = 0; |
| int bus = (int)strtol(bus_str, &bus_suffix, 10); |
| if (errno != 0 || bus_str == bus_suffix) { |
| msg_perr("%s: Could not convert 'bus'.\n", __func__); |
| return -1; |
| } |
| |
| if (strlen(bus_suffix) > 0) { |
| msg_perr("%s: Garbage following 'bus' value.\n", __func__); |
| return -1; |
| } |
| |
| msg_pinfo("Using I2C bus %d.\n", bus); |
| return bus; |
| } |
| |
| int i2c_open_from_programmer_params(uint16_t addr, int force) |
| { |
| int fd = -1; |
| |
| char *bus_str = extract_programmer_param("bus"); |
| char *device_path = extract_programmer_param("devpath"); |
| |
| if (device_path != NULL && bus_str != NULL) { |
| msg_perr("%s: only one of bus and devpath may be specified\n", __func__); |
| goto out; |
| } |
| if (device_path == NULL && bus_str == NULL) { |
| msg_perr("%s: one of bus and devpath must be specified\n", __func__); |
| goto out; |
| } |
| |
| if (device_path != NULL) |
| fd = i2c_open_path(device_path, addr, force); |
| else |
| fd = i2c_open(get_bus_number(bus_str), addr, force); |
| |
| out: |
| free(bus_str); |
| free(device_path); |
| return 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); |
| } |