SMBus.hpp
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/****************************************************************************
*
* Copyright (c) 2018 PX4 Development Team. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/**
* @file SMBus.hpp
* SMBus v2.0 protocol implementation.
*
* @author Jacob Dahl <dahl.jakejacob@gmail.com>
* @author Bazooka Joe <BazookaJoe1900@gmail.com>
*/
#include <drivers/device/i2c.h>
#include <perf/perf_counter.h>
#include <string.h>
#define SMBUS_PEC_POLYNOMIAL 0x07 ///< Polynomial for calculating PEC
class SMBus : public device::I2C
{
public:
static constexpr uint8_t MAX_BLOCK_LEN = 34;
SMBus(int bus_num, uint16_t address);
~SMBus() override;
/**
* @brief Sends a block write command.
* @param cmd_code The command code.
* @param data The data to be written.
* @param length The number of bytes being written. Maximum is SMBus::MAX_BLOCK_LEN.
* @return Returns PX4_OK on success, -errno on failure.
*/
int block_write(const uint8_t cmd_code, const void *data, uint8_t byte_count, const bool use_pec);
/**
* @brief Sends a block read command.
* @param cmd_code The command code.
* @param data The returned data.
* @param length The number of bytes being read. Maximum is SMBus::MAX_BLOCK_LEN.
* @return Returns PX4_OK on success, -errno on failure.
*/
int block_read(const uint8_t cmd_code, void *data, const uint8_t length, const bool use_pec);
/**
* @brief Sends a read word command.
* @param cmd_code The command code.
* @param data The 2 bytes of returned data plus a 1 byte CRC if used.
* @return Returns PX4_OK on success, -errno on failure.
*/
int read_word(const uint8_t cmd_code, uint16_t &data);
/**
* @brief Sends a write word command.
* @param cmd_code The command code.
* @param data The 2 bytes of data to be transfered.
* @return Returns PX4_OK on success, -errno on failure.
*/
int write_word(const uint8_t cmd_code, uint16_t data);
/**
* @brief Calculates the PEC from the data.
* @param buffer The buffer that stores the data to perform the CRC over.
* @param length The number of bytes being written.
* @return Returns PX4_OK on success, -errno on failure.
*/
uint8_t get_pec(uint8_t *buffer, uint8_t length);
perf_counter_t _interface_errors{perf_alloc(PC_COUNT, MODULE_NAME": errors")};
};