BMP280_SPI.cpp

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/**
 * @file bmp280_spi.cpp
 *
 * SPI interface for BMP280
 */

#include "bmp280.h"

#include <px4_platform_common/px4_config.h>
#include <drivers/device/spi.h>

#if defined(PX4_SPIDEV_BARO) || defined(PX4_SPIDEV_EXT_BARO)

/* SPI protocol address bits */
#define DIR_READ            (1<<7)  //for set
#define DIR_WRITE           ~(1<<7) //for clear

#pragma pack(push,1)
struct spi_data_s {
    uint8_t addr;
    struct bmp280::data_s data;
};

struct spi_calibration_s {
    uint8_t addr;
    struct bmp280::calibration_s cal;
};
#pragma pack(pop)

class BMP280_SPI: public device::SPI, public bmp280::IBMP280
{
public:
    BMP280_SPI(uint8_t bus, uint32_t device);
    virtual ~BMP280_SPI() override = default;

    int init() override { return SPI::init(); }

    uint8_t get_reg(uint8_t addr) override;
    int set_reg(uint8_t value, uint8_t addr) override;

    bmp280::data_s      *get_data(uint8_t addr) override;
    bmp280::calibration_s   *get_calibration(uint8_t addr) override;

    uint32_t get_device_id() const override { return device::SPI::get_device_id(); }

private:
    spi_calibration_s   _cal{};
    spi_data_s      _data{};
};

bmp280::IBMP280 *
bmp280_spi_interface(uint8_t busnum, uint32_t device)
{
    return new BMP280_SPI(busnum, device);
}

BMP280_SPI::BMP280_SPI(uint8_t bus, uint32_t device) :
    SPI("BMP280_SPI", nullptr, bus, device, SPIDEV_MODE3, 10 * 1000 * 1000)
{
}

uint8_t
BMP280_SPI::get_reg(uint8_t addr)
{
    uint8_t cmd[2] = { (uint8_t)(addr | DIR_READ), 0}; // set MSB bit
    transfer(&cmd[0], &cmd[0], 2);

    return cmd[1];
}

int
BMP280_SPI::set_reg(uint8_t value, uint8_t addr)
{
    uint8_t cmd[2] = { (uint8_t)(addr & DIR_WRITE), value}; // clear MSB bit
    return transfer(&cmd[0], nullptr, 2);
}

bmp280::data_s *
BMP280_SPI::get_data(uint8_t addr)
{
    _data.addr = (uint8_t)(addr | DIR_READ); // set MSB bit

    if (transfer((uint8_t *)&_data, (uint8_t *)&_data, sizeof(spi_data_s)) == OK) {
        return &(_data.data);

    } else {
        return nullptr;
    }
}

bmp280::calibration_s *
BMP280_SPI::get_calibration(uint8_t addr)
{
    _cal.addr = addr | DIR_READ;

    if (transfer((uint8_t *)&_cal, (uint8_t *)&_cal, sizeof(spi_calibration_s)) == OK) {
        return &(_cal.cal);

    } else {
        return nullptr;
    }
}

#endif /* PX4_SPIDEV_BARO || PX4_SPIDEV_EXT_BARO */