bizhang_-obav/src/drivers/magnetometer/rm3100/rm3100_i2c.cpp

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/**
 * @file rm3100_i2c.cpp
 *
 * I2C interface for RM3100
 */

#include <px4_platform_common/px4_config.h>

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



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

#include "board_config.h"
#include "rm3100.h"

#if defined(PX4_I2C_BUS_ONBOARD) || defined(PX4_I2C_BUS_EXPANSION)

#define RM3100_ADDRESS		0x20

class RM3100_I2C : public device::I2C
{
public:
	RM3100_I2C(int bus);
	virtual ~RM3100_I2C() = default;

	virtual int     init();
	virtual int     ioctl(unsigned operation, unsigned &arg);
	virtual int     read(unsigned address, void *data, unsigned count);
	virtual int     write(unsigned address, void *data, unsigned count);

protected:
	virtual int     probe();

};

device::Device *
RM3100_I2C_interface(int bus);

device::Device *
RM3100_I2C_interface(int bus)
{
	return new RM3100_I2C(bus);
}

RM3100_I2C::RM3100_I2C(int bus) :
	I2C("RM300_I2C", nullptr, bus, RM3100_ADDRESS, 400000)
{
	_device_id.devid_s.devtype = DRV_MAG_DEVTYPE_RM3100;
}

int
RM3100_I2C::init()
{
	/* this will call probe() */
	return I2C::init();
}

int
RM3100_I2C::ioctl(unsigned operation, unsigned &arg)
{
	switch (operation) {

	case MAGIOCGEXTERNAL:
		return external();

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

	default:
		return  -EINVAL;
	}
}

int
RM3100_I2C::probe()
{
	uint8_t data = 0;

	_retries = 10;

	if (read(ADDR_REVID, &data, 1)) {
		DEVICE_DEBUG("RM3100 read_reg fail");
		return -EIO;
	}

	_retries = 2;

	if (data != RM3100_REVID) {
		DEVICE_DEBUG("RM3100 bad ID: %02x", data);
		return -EIO;
	}

	return OK;
}

int
RM3100_I2C::read(unsigned address, void *data, unsigned count)
{
	uint8_t cmd = address;
	int ret;

	/* We need a first transfer where we write the register to read */
	ret = transfer(&cmd, 1, nullptr, 0);

	if (ret != OK) {
		return ret;
	}

	/* Now we read the previously selected register */
	ret = transfer(nullptr, 0, (uint8_t *)data, count);

	return ret;
}

int
RM3100_I2C::write(unsigned address, void *data, unsigned count)
{
	uint8_t buf[32];

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

	buf[0] = address;
	memcpy(&buf[1], data, count);

	return transfer(&buf[0], count + 1, nullptr, 0);
}

#endif /* PX4_I2C_OBDEV_RM3100 */