| /* |
| * 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. |
| */ |
| |
| #ifndef I2C_HELPER_H |
| #define I2C_HELPER_H |
| |
| #include <inttypes.h> |
| |
| /** |
| * An convinent structure that contains the buffer size and the buffer |
| * pointer. Used to wrap buffer details while doing the I2C data |
| * transfer on both input and output. It is the client's responsibility |
| * to use i2c_buffer_t_fill to initialize this struct instead of |
| * trying to construct it directly. |
| */ |
| typedef struct { |
| void *buf; |
| uint16_t len; |
| } i2c_buffer_t; |
| |
| /** |
| * i2c_buffer_t_fill - fills in the i2c_buffer_t |
| * |
| * @i2c_buf: pointer to the be constructed. |
| * @buf: buffer contains data to be included in i2c_buffer_t. |
| * @len: length of buffer to be included in i2c_buffer_t. |
| * |
| * This function takes in a pointer to an initialized i2c_buffer_t |
| * object with related information, and fill in the i2c_buffer_t with |
| * some validation applied. The function does allow initialization with |
| * NULL buffer but will make sure len == 0 in such case. |
| * |
| * returns 0 on success, <0 to indicate failure |
| */ |
| static inline int i2c_buffer_t_fill(i2c_buffer_t *i2c_buf, void *buf, uint16_t len) |
| { |
| if (!i2c_buf || (!buf && len)) |
| return -1; |
| |
| i2c_buf->buf = buf; |
| i2c_buf->len = len; |
| |
| return 0; |
| } |
| |
| /** |
| * i2c_open - opens the target I2C device and set the I2C slave address |
| * |
| * @bus: I2C bus number of the target device. |
| * @addr: I2C slave address. |
| * @force: whether to force set the I2C slave address. |
| * |
| * This function returns a file descriptor for the target device. It is |
| * the client's responsibility to pass the return value to i2c_close to |
| * clean up. |
| * |
| * returns fd of target device on success, <0 to indicate failure |
| */ |
| int i2c_open(int bus, uint16_t addr, int force); |
| |
| /** |
| * i2c_close - closes the file descriptor returned by i2c_open |
| * |
| * @fd: file descriptor to be closed. |
| * |
| * It is the client's responsibility to set fd = -1 when it is |
| * done with it. |
| * |
| * returns 0 on success, <0 to indicate failure |
| */ |
| int i2c_close(int fd); |
| |
| /** |
| * i2c_read - reads data from the I2C device |
| * |
| * @fd: file descriptor of the target device. |
| * @addr: I2C slave address of the target device. |
| * @buf_read: data struct includes reading buffer and size. |
| * |
| * This function does accept empty read and do nothing on such case. |
| * |
| * returns read length on success, <0 to indicate failure |
| */ |
| int i2c_read(int fd, uint16_t addr, i2c_buffer_t *buf_read); |
| |
| /** |
| * i2c_write - writes command/data into the I2C device |
| * |
| * @fd: file descriptor of the target device. |
| * @addr: I2C slave address of the target device. |
| * @buf_write: data struct includes writting buffer and size. |
| * |
| * This function does accept empty write and do nothing on such case. |
| * |
| * returns wrote length on success, <0 to indicate failure. |
| */ |
| int i2c_write(int fd, uint16_t addr, const i2c_buffer_t *buf_write); |
| |
| #endif /* !I2C_HELPER_H */ |