text: /****************************************************************************
   *
   *   Copyright (c) 2013-2015 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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   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /**
   * @file HMC5883_I2C.cpp
   *
   * I2C interface for HMC5883 / HMC 5983
   */
  
  /* XXX trim includes */
  #include <px4_config.h>
  
  #include <sys/types.h>
  #include <stdint.h>
  #include <stdbool.h>
  #include <string.h>
  #include <assert.h>
  #include <debug.h>
  #include <errno.h>
  #include <unistd.h>
  
  #include <arch/board/board.h>
  
  #include <drivers/device/i2c.h>
  #include <drivers/drv_mag.h>
  #include <drivers/drv_device.h>
  
  #include "hmc5883.h"
  
  #include "board_config.h"
  
  #ifdef PX4_I2C_OBDEV_HMC5883
  
  #define HMC5883L_ADDRESS		PX4_I2C_OBDEV_HMC5883
  
  device::Device *HMC5883_I2C_interface(int bus);
  
  class HMC5883_I2C : public device::I2C
  {
  public:
  	HMC5883_I2C(int bus);
  	virtual ~HMC5883_I2C();
  
  	virtual int	init();
  	virtual int	read(unsigned address, void *data, unsigned count);
  	virtual int	write(unsigned address, void *data, unsigned count);
  
  	virtual int	ioctl(unsigned operation, unsigned &arg);
  
  protected:
  	virtual int	probe();
  
  };
  
  device::Device *
  HMC5883_I2C_interface(int bus)
  {
  	return new HMC5883_I2C(bus);
  }
  
  HMC5883_I2C::HMC5883_I2C(int bus) :
  	I2C("HMC5883_I2C", nullptr, bus, HMC5883L_ADDRESS, 400000)
  {
  	_device_id.devid_s.devtype = DRV_MAG_DEVTYPE_HMC5883;
  }
  
  HMC5883_I2C::~HMC5883_I2C()
  {
  }
  
  int
  HMC5883_I2C::init()
  {
  	/* this will call probe() */
  	return I2C::init();
  }
  
  int
  HMC5883_I2C::ioctl(unsigned operation, unsigned &arg)
  {
  	int ret;
  
  	switch (operation) {
  
  	case MAGIOCGEXTERNAL:
  // On PX4v1 the MAG can be on an internal I2C
  // On everything else its always external
  #ifdef CONFIG_ARCH_BOARD_PX4FMU_V1
  		if (_bus == PX4_I2C_BUS_EXPANSION) {
  			return 1;
  
  		} else {
  			return 0;
  		}
  
  #else
  		return 1;
  #endif
  
  	case DEVIOCGDEVICEID:
  		return CDev::ioctl(nullptr, operation, arg);
  
  	default:
  		ret = -EINVAL;
  	}
  
  	return ret;
  }
  
  int
  HMC5883_I2C::probe()
  {
  	uint8_t data[3] = {0, 0, 0};
  
  	_retries = 10;
  
  	if (read(ADDR_ID_A, &data[0], 1) ||
  	    read(ADDR_ID_B, &data[1], 1) ||
  	    read(ADDR_ID_C, &data[2], 1)) {
  		DEVICE_DEBUG("read_reg fail");
  		return -EIO;
  	}
  
  	_retries = 2;
  
  	if ((data[0] != ID_A_WHO_AM_I) ||
  	    (data[1] != ID_B_WHO_AM_I) ||
  	    (data[2] != ID_C_WHO_AM_I)) {
  		DEVICE_DEBUG("ID byte mismatch (%02x,%02x,%02x)", data[0], data[1], data[2]);
  		return -EIO;
  	}
  
  	return OK;
  }
  
  int
  HMC5883_I2C::write(unsigned address, void *data, unsigned count)
  {
  	uint8_t buf[32];
  
  	if (sizeof(buf) < (count + 1)) {
  		return -EIO;
  	}
  
  	buf[0] = address;
  	memcpy(&buf[1], data, count);
  
  	return transfer(&buf[0], count + 1, nullptr, 0);
  }
  
  int
  HMC5883_I2C::read(unsigned address, void *data, unsigned count)
  {
  	uint8_t cmd = address;
  	return transfer(&cmd, 1, (uint8_t *)data, count);
  }
  
  #endif /* PX4_I2C_OBDEV_HMC5883 */
  