lis3mdl_spi.cpp

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/**
 * @file lis3mdl_spi.cpp
 *
 * SPI interface for LIS3MDL
 */

#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 <arch/board/board.h>

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

#include "board_config.h"
#include "lis3mdl.h"

#ifdef PX4_SPIDEV_LIS

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

class LIS3MDL_SPI : public device::SPI
{
public:
    LIS3MDL_SPI(int bus, uint32_t device);
    virtual ~LIS3MDL_SPI() = 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);
};

device::Device *
LIS3MDL_SPI_interface(int bus);

device::Device *
LIS3MDL_SPI_interface(int bus)
{
    return new LIS3MDL_SPI(bus, PX4_SPIDEV_LIS);
}

LIS3MDL_SPI::LIS3MDL_SPI(int bus, uint32_t device) :
    SPI("LIS3MDL_SPI", nullptr, bus, device, SPIDEV_MODE3, 11 * 1000 * 1000 /* will be rounded to 10.4 MHz */)
{
    _device_id.devid_s.devtype = DRV_MAG_DEVTYPE_LIS3MDL;
}

int
LIS3MDL_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("LIS3MDL read_reg fail");
    }

    if (data != ID_WHO_AM_I) {
        DEVICE_DEBUG("LIS3MDL bad ID: %02x", data);
        return -EIO;
    }

    return OK;
}

int
LIS3MDL_SPI::ioctl(unsigned operation, unsigned &arg)
{
    int ret;

    switch (operation) {

    case MAGIOCGEXTERNAL:
        /*
         * Even if this sensor is on the external SPI
         * bus it is still internal to the autopilot
         * assembly, so always return 0 for internal.
         */
        return 0;

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

    default: {
            ret = -EINVAL;
        }
    }

    return ret;
}

int
LIS3MDL_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
LIS3MDL_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);
}

#endif /* PX4_SPIDEV_LIS */