text: /****************************************************************************
   *
   *   Copyright (c) 2016 PX4 Development Team. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   * 3. Neither the name PX4 nor the names of its contributors may be
   *    used to endorse or promote products derived from this software
   *    without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
   * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
   * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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   ****************************************************************************/
  
  /**
   * @file mag_i2c.cpp
   *
   * I2C interface for AK8963
   */
  
  #include "icm20948.h"
  #include "ICM20948_mag.h"
  
  #include <drivers/device/i2c.h>
  
  #ifdef USE_I2C
  
  device::Device *AK8963_I2C_interface(int bus, bool external_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, bool external_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[MPU_MAX_WRITE_BUFFER_SIZE] {};
  
  	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 // USE_I2C
  