lis2mdl_spi.cpp 3.82 KB
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/**
 * @file lis2mdl_spi.cpp
 *
 * SPI interface for LIS2MDL
 */

#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/spi.h>

#include "board_config.h"
#include "lis2mdl.h"

/* SPI protocol address bits */
#define DIR_READ        (1<<7)
#define DIR_WRITE       (0<<7)
#define ADDR_INCREMENT  (1<<6)

class LIS2MDL_SPI : public device::SPI
{
public:
	LIS2MDL_SPI(int bus, uint32_t devid, int bus_frequency, spi_mode_e spi_mode);
	virtual ~LIS2MDL_SPI() = default;

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

device::Device *
LIS2MDL_SPI_interface(int bus, uint32_t devid, int bus_frequency, spi_mode_e spi_mode);

device::Device *
LIS2MDL_SPI_interface(int bus, uint32_t devid, int bus_frequency, spi_mode_e spi_mode)
{
	return new LIS2MDL_SPI(bus, devid, bus_frequency, spi_mode);
}

LIS2MDL_SPI::LIS2MDL_SPI(int bus, uint32_t devid, int bus_frequency, spi_mode_e spi_mode) :
	SPI(DRV_MAG_DEVTYPE_LIS2MDL, "LIS2MDL_SPI", bus, devid, spi_mode, bus_frequency)
{
}

int
LIS2MDL_SPI::init()
{
	int ret;

	ret = SPI::init();

	if (ret != OK) {
		DEVICE_DEBUG("SPI init failed");
		return -EIO;
	}

	// read WHO_AM_I value
	uint8_t data = 0;

	if (read(ADDR_WHO_AM_I, &data, 1)) {
		DEVICE_DEBUG("LIS2MDL read_reg fail");
	}

	if (data != ID_WHO_AM_I) {
		DEVICE_DEBUG("LIS2MDL bad ID: %02x", data);
		return -EIO;
	}

	return OK;
}

int
LIS2MDL_SPI::read(unsigned address, void *data, unsigned count)
{
	uint8_t buf[32];

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

	buf[0] = address | DIR_READ | ADDR_INCREMENT;

	int ret = transfer(&buf[0], &buf[0], count + 1);
	memcpy(data, &buf[1], count);
	return ret;
}

int
LIS2MDL_SPI::write(unsigned address, void *data, unsigned count)
{
	uint8_t buf[32];

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

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

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