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 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
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 *    used to endorse or promote products derived from this software
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/**
 * @file mpu9250_i2c.cpp
 *
 * I2C interface for MPU9250
 */

#include <drivers/device/i2c.h>

#include "mpu9250.h"

#ifdef USE_I2C

device::Device *MPU9250_I2C_interface(int bus, uint32_t address, bool external_bus);

class MPU9250_I2C : public device::I2C
{
public:
	MPU9250_I2C(int bus, uint32_t address);
	~MPU9250_I2C() override = default;

	int	read(unsigned address, void *data, unsigned count) override;
	int	write(unsigned address, void *data, unsigned count) override;

protected:
	virtual int	probe();

private:

};

device::Device *
MPU9250_I2C_interface(int bus, uint32_t address, bool external_bus)
{
	return new MPU9250_I2C(bus, address);
}

MPU9250_I2C::MPU9250_I2C(int bus, uint32_t address) :
	I2C("MPU9250_I2C", nullptr, bus, address, 400000)
{
	_device_id.devid_s.devtype = DRV_ACC_DEVTYPE_MPU9250;
}

int
MPU9250_I2C::write(unsigned reg_speed, void *data, unsigned count)
{
	uint8_t cmd[MPU_MAX_WRITE_BUFFER_SIZE] {};

	if (sizeof(cmd) < (count + 1)) {
		return -EIO;
	}

	cmd[0] = MPU9250_REG(reg_speed);
	cmd[1] = *(uint8_t *)data;
	return transfer(&cmd[0], count + 1, nullptr, 0);
}

int
MPU9250_I2C::read(unsigned reg_speed, void *data, unsigned count)
{
	/* We want to avoid copying the data of MPUReport: So if the caller
	 * supplies a buffer not MPUReport in size, it is assume to be a reg or
	 * reg 16 read
	 * Since MPUReport has a cmd at front, we must return the data
	 * after that. Foe anthing else we must return it
	 */
	uint32_t offset = count < sizeof(MPUReport) ? 0 : offsetof(MPUReport, status);
	uint8_t cmd = MPU9250_REG(reg_speed);
	return transfer(&cmd, 1, &((uint8_t *)data)[offset], count);
}

int
MPU9250_I2C::probe()
{
	uint8_t whoami = 0;

	// Try first for mpu9250/6500
	read(MPUREG_WHOAMI, &whoami, 1);

	if (whoami == MPU_WHOAMI_9250 || whoami == MPU_WHOAMI_6500) {
		return PX4_OK;
	}

	return -ENODEV;
}

#endif /* USE_I2C */
