PX4-Autopilot/src/drivers/mpu6000/mpu6000_i2c.cpp

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/**
 * @file mpu6000_i2c.cpp
 *
 * I2C interface for MPU6000 /MPU6050
 */

/* XXX trim includes */
#include <px4_config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <assert.h>
#include <debug.h>
#include <errno.h>
#include <unistd.h>

#include <arch/board/board.h>

#include <drivers/device/i2c.h>
#include <drivers/drv_accel.h>
#include <drivers/drv_device.h>

#include "mpu6000.h"

#include "board_config.h"

#ifdef USE_I2C

device::Device *MPU6000_I2C_interface(int bus, int device_type, bool external_bus);

class MPU6000_I2C : public device::I2C
{
public:
	MPU6000_I2C(int bus, int device_type);
	virtual ~MPU6000_I2C();

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

	virtual int	ioctl(unsigned operation, unsigned &arg);

protected:
	virtual int	probe();

private:
	int _device_type;

};


device::Device *
MPU6000_I2C_interface(int bus, int device_type, bool external_bus)
{
	return new MPU6000_I2C(bus, device_type);
}

MPU6000_I2C::MPU6000_I2C(int bus, int device_type) :
	I2C("MPU6000_I2C", nullptr, bus, PX4_I2C_MPU6050_ADDR, 400000),
	_device_type(device_type)
{
	_device_id.devid_s.devtype =  DRV_ACC_DEVTYPE_MPU6000;
}

MPU6000_I2C::~MPU6000_I2C()
{
}

int
MPU6000_I2C::init()
{
	/* this will call probe() */
	return I2C::init();
}

int
MPU6000_I2C::ioctl(unsigned operation, unsigned &arg)
{
	int ret;

	switch (operation) {

	case ACCELIOCGEXTERNAL:
		return _bus == PX4_I2C_BUS_EXPANSION ? 1 : 0;

	case DEVIOCGDEVICEID:
		return CDev::ioctl(nullptr, operation, arg);

	case MPUIOCGIS_I2C:
		return 1;

	default:
		ret = -EINVAL;
	}

	return ret;
}

int
MPU6000_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] = MPU6000_REG(reg_speed);
	cmd[1] = *(uint8_t *)data;
	return transfer(&cmd[0], count + 1, nullptr, 0);
}

int
MPU6000_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 = MPU6000_REG(reg_speed);
	int ret = transfer(&cmd, 1, &((uint8_t *)data)[offset], count);
	return ret == OK ? count : ret;
}


int
MPU6000_I2C::probe()
{
	uint8_t whoami = 0;
	uint8_t expected = _device_type == 6000 ? MPU_WHOAMI_6000 : ICM_WHOAMI_20608;
	return (read(MPUREG_WHOAMI, &whoami, 1) > 0 && (whoami == expected)) ? 0 : -EIO;

}
#endif /* PX4_I2C_OBDEV_HMC5883 */