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dc2c83bbc7
See https://www.kernel.org/doc/Documentation/i2c/ for details. This creates common interface for I2C access functions, and adds implementation for linux I2C functions. BUG=b:148746232 BRANCH=none TEST=build success Signed-off-by: Shiyu Sun <sshiyu@chromium.org> Change-Id: Ie0487824dfb71970bede17f617dbbb30ddf78c12 Reviewed-on: https://review.coreboot.org/c/flashrom/+/39686 Tested-by: Edward O'Callaghan <quasisec@chromium.org> Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
114 lines
2.6 KiB
C
114 lines
2.6 KiB
C
/*
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* This file is part of the flashrom project.
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*
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* Copyright (C) 2020 The Chromium OS Authors
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/fcntl.h>
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#include <sys/ioctl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <linux/i2c.h>
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#include <linux/i2c-dev.h>
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#include "flash.h"
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#include "i2c_helper.h"
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#define I2C_DEV_PREFIX "/dev/i2c-"
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#define I2C_MAX_BUS 255
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int i2c_close(int fd)
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{
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return fd == -1 ? 0 : close(fd);
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}
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int i2c_open(int bus, uint16_t addr, int force)
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{
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int ret = -1;
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int fd = -1;
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/* Maximum i2c bus number is 255(3 char), +1 for null terminated string. */
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int path_len = strlen(I2C_DEV_PREFIX) + 4;
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int request = force ? I2C_SLAVE_FORCE : I2C_SLAVE;
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if (bus < 0 || bus > I2C_MAX_BUS) {
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msg_perr("Invalid I2C bus %d.\n", bus);
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return ret;
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}
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char *dev = calloc(1, path_len);
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if (!dev) {
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msg_perr("Unable to allocate space for device name of len %d: %s.\n",
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path_len, strerror(errno));
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goto linux_i2c_open_err;
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}
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ret = snprintf(dev, path_len, "%s%d", I2C_DEV_PREFIX, bus);
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if (ret < 0) {
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msg_perr("Unable to join bus number to device name: %s.\n", strerror(errno));
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goto linux_i2c_open_err;
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}
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fd = open(dev, O_RDWR);
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if (fd < 0) {
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msg_perr("Unable to open I2C device %s: %s.\n", dev, strerror(errno));
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ret = fd;
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goto linux_i2c_open_err;
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}
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ret = ioctl(fd, request, addr);
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if (ret < 0) {
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msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
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i2c_close(fd);
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goto linux_i2c_open_err;
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}
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linux_i2c_open_err:
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if (dev)
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free(dev);
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return ret ? ret : fd;
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}
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int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf)
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{
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if (buf->len == 0)
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return 0;
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int ret = ioctl(fd, I2C_SLAVE, addr);
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if (ret < 0) {
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msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
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return ret;
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}
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return read(fd, buf->buf, buf->len);
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}
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int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf)
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{
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if (buf->len == 0)
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return 0;
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int ret = ioctl(fd, I2C_SLAVE, addr);
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if (ret < 0) {
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msg_perr("Unable to set I2C slave address to 0x%02x: %s.\n", addr, strerror(errno));
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return ret;
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}
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return write(fd, buf->buf, buf->len);
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}
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