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/**
 * @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:
	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.
	 * @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. The returned data will always contain 2 bytes of address information followed by data[length].
	 * @param length The number of bytes being read.
	 * @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")};

};