mirror of
https://github.com/openharmony/drivers_framework.git
synced 2026-08-27 02:42:28 -04:00
yanghaizhou
147 lines
4.6 KiB
C
147 lines
4.6 KiB
C
/*
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* Copyright (c) 2020-2021 Huawei Device Co., Ltd.
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*
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* HDF is dual licensed: you can use it either under the terms of
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* the GPL, or the BSD license, at your option.
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* See the LICENSE file in the root of this repository for complete details.
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*/
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/**
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* @addtogroup I2C
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* @{
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*
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* @brief Provides standard Inter-Integrated Circuit (I2C) interfaces.
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*
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* This module allows a driver to perform operations on an I2C controller for accessing devices on the I2C bus,
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* including creating and destroying I2C controller handles as well as reading and writing data.
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*
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* @since 1.0
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*/
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/**
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* @file i2c_if.h
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*
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* @brief Declares the standard I2C interface functions.
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*
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* @since 1.0
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*/
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#ifndef I2C_IF_H
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#define I2C_IF_H
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#include "platform_if.h"
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#ifdef __cplusplus
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#if __cplusplus
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extern "C" {
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#endif
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#endif /* __cplusplus */
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/**
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* @brief Defines the I2C transfer message used during custom transfers.
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*
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* @attention This structure does not limit the data transfer length specified by <b>len</b>.
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* The specific I2C controller determines the maximum length allowed. \n
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* The device address <b>addr</b> indicates the original device address and does not need to
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* contain the read/write flag bit.
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*
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* @since 1.0
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*/
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struct I2cMsg {
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/** Address of the I2C device */
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uint16_t addr;
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/** Address of the buffer for storing transferred data */
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uint8_t *buf;
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/** Length of the transferred data */
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uint16_t len;
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/**
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* Transfer Mode Flag | Description
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* ------------| -----------------------
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* I2C_FLAG_READ | Read flag
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* I2C_FLAG_ADDR_10BIT | 10-bit addressing flag
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* I2C_FLAG_READ_NO_ACK | No-ACK read flag
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* I2C_FLAG_IGNORE_NO_ACK | Ignoring no-ACK flag
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* I2C_FLAG_NO_START | No START condition flag
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* I2C_FLAG_STOP | STOP condition flag
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*/
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uint16_t flags;
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};
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/**
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* @brief Enumerates flags used for transferring I2C messages.
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*
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* Multiple flags can be used to jointly control a single I2C message transfer.
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* If a bit is set to <b>1</b>, the corresponding feature is enabled. If a bit is set to <b>0</b>,
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* the corresponding feature is disabled.
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*
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* @since 1.0
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*/
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enum I2cFlag {
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/** Read flag. The value <b>1</b> indicates the read operation, and <b>0</b> indicates the write operation. */
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I2C_FLAG_READ = (0x1 << 0),
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/** 10-bit addressing flag. The value <b>1</b> indicates that a 10-bit address is used. */
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I2C_FLAG_ADDR_10BIT = (0x1 << 4),
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/** Non-ACK read flag. The value <b>1</b> indicates that no ACK signal is sent during the read process. */
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I2C_FLAG_READ_NO_ACK = (0x1 << 11),
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/** Ignoring no-ACK flag. The value <b>1</b> indicates that the non-ACK signal is ignored. */
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I2C_FLAG_IGNORE_NO_ACK = (0x1 << 12),
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/**
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* No START condition flag. The value <b>1</b> indicates that there is no START condition for the message
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* transfer.
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*/
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I2C_FLAG_NO_START = (0x1 << 14),
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/** STOP condition flag. The value <b>1</b> indicates that the current transfer ends with a STOP condition. */
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I2C_FLAG_STOP = (0x1 << 15),
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};
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/**
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* @brief Obtains the handle of an I2C controller.
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*
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* You must call this function before accessing the I2C bus.
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*
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* @param number Indicates the I2C controller ID.
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*
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* @return Returns the pointer to the {@link DevHandle} of the I2C controller if the operation is successful;
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* returns <b>NULL</b> otherwise.
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* @since 1.0
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*/
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DevHandle I2cOpen(int16_t number);
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/**
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* @brief Releases the handle of an I2C controller.
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*
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* If you no longer need to access the I2C controller, you should call this function to close its handle so as
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* to release unused memory resources.
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*
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* @param handle Indicates the pointer to the device handle of the I2C controller.
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*
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* @since 1.0
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*/
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void I2cClose(DevHandle handle);
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/**
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* @brief Launches a custom transfer to an I2C device.
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*
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* @param handle Indicates the pointer to the device handle of the I2C controller obtained via {@link I2cOpen}.
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* @param msgs Indicates the pointer to the I2C transfer message structure array.
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* @param count Indicates the length of the message structure array.
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*
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* @return Returns the number of transferred message structures if the operation is successful;
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* returns a negative value otherwise.
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* @see I2cMsg
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* @attention This function does not limit the number of message structures specified by <b>count</b> or the data
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* length of each message structure. The specific I2C controller determines the maximum number and data length allowed.
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*
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* @since 1.0
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*/
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int32_t I2cTransfer(DevHandle handle, struct I2cMsg *msgs, int16_t count);
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#ifdef __cplusplus
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#if __cplusplus
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}
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#endif
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#endif /* __cplusplus */
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#endif /* I2C_IF_H */
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/** @} */
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