AK8963_I2C.cpp

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/**
 * @file mag_i2c.cpp
 *
 * I2C interface for AK8963
 */

#include <px4_platform_common/px4_config.h>
#include <drivers/device/i2c.h>
#include <drivers/drv_device.h>

#include "mpu9250.h"
#include "MPU9250_mag.h"

#ifdef USE_I2C

device::Device *AK8963_I2C_interface(int bus);

class AK8963_I2C : public device::I2C
{
public:
    AK8963_I2C(int bus);
    ~AK8963_I2C() override = default;

    int read(unsigned address, void *data, unsigned count) override;
    int write(unsigned address, void *data, unsigned count) override;

protected:
    int probe() override;

};

device::Device *
AK8963_I2C_interface(int bus)
{
    return new AK8963_I2C(bus);
}

AK8963_I2C::AK8963_I2C(int bus) : I2C("AK8963_I2C", nullptr, bus, AK8963_I2C_ADDR, 400000)
{
    _device_id.devid_s.devtype = DRV_MAG_DEVTYPE_MPU9250;
}

int
AK8963_I2C::write(unsigned reg_speed, void *data, unsigned count)
{
    uint8_t cmd[2] {};

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

    cmd[0] = MPU9250_REG(reg_speed);
    cmd[1] = *(uint8_t *)data;
    return transfer(&cmd[0], count + 1, nullptr, 0);
}

int
AK8963_I2C::read(unsigned reg_speed, void *data, unsigned count)
{
    uint8_t cmd = MPU9250_REG(reg_speed);
    return transfer(&cmd, 1, (uint8_t *)data, count);
}

int
AK8963_I2C::probe()
{
    uint8_t whoami = 0;
    uint8_t expected = AK8963_DEVICE_ID;

    if (PX4_OK != read(AK8963REG_WIA, &whoami, 1)) {
        return -EIO;
    }

    if (whoami != expected) {
        return -EIO;
    }

    return OK;
}

#endif