LPS22HB_SPI.cpp

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/**
 * @file LPS22HB_SPI.cpp
 *
 * SPI interface for LPS22HB
 */

#include "LPS22HB.hpp"

#ifdef PX4_SPIDEV_LPS22HB

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

device::Device *LPS22HB_SPI_interface(int bus);

class LPS22HB_SPI : public device::SPI
{
public:
    LPS22HB_SPI(int bus, uint32_t device);
    virtual ~LPS22HB_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 *
LPS22HB_SPI_interface(int bus)
{
    return new LPS22HB_SPI(bus, PX4_SPIDEV_LPS22HB);
}

LPS22HB_SPI::LPS22HB_SPI(int bus, uint32_t device) : SPI("LPS22HB_SPI", nullptr, bus, device, SPIDEV_MODE3, 10000000)
{
    _device_id.devid_s.devtype = DRV_BARO_DEVTYPE_LPS22HB;
}

int
LPS22HB_SPI::init()
{
    int ret = SPI::init();

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

    // read WHO_AM_I value
    uint8_t id = 0;

    if (read(WHO_AM_I, &id, 1)) {
        DEVICE_DEBUG("read_reg fail");
        return -EIO;
    }

    if (id != LPS22HB_ID_WHO_AM_I) {
        DEVICE_DEBUG("ID byte mismatch (%02x != %02x)", LPS22HB_ID_WHO_AM_I, id);
        return -EIO;
    }

    return OK;
}

int
LPS22HB_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);
}

int
LPS22HB_SPI::read(unsigned address, void *data, unsigned count)
{
    uint8_t buf[32];

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

    buf[0] = address | DIR_READ;

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

#endif /* PX4_SPIDEV_LPS22HB */