text: /****************************************************************************
   *
   *   Copyright (C) 2012 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,
   * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
   * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
   * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   ****************************************************************************/
  
  /**
   * @file i2c.h
   *
   * Base class for devices connected via I2C.
   */
  
  #ifndef _DEVICE_I2C_H
  #define _DEVICE_I2C_H
  
  #include "vdev.h"
  
  #include <px4_i2c.h>
  #ifdef __PX4_LINUX
  #include <linux/i2c.h>
  #include <linux/i2c-dev.h>
  #endif
  #include <string>
  
  namespace device __EXPORT
  {
  
  /**
   * Abstract class for character device on I2C
   */
  class __EXPORT I2C : public CDev
  {
  
  public:
  
  	/**
  	 * Get the address
  	 */
  	int16_t		get_address() const { return _address; }
  
  protected:
  	/**
  	 * The number of times a read or write operation will be retried on
  	 * error.
  	 */
  	unsigned		_retries;
  
  	/**
  	 * The I2C bus number the device is attached to.
  	 */
  	int			_bus;
  
  	/**
  	 * @ Constructor
  	 *
  	 * @param name		Driver name
  	 * @param devname	Device node name
  	 * @param bus		I2C bus on which the device lives
  	 * @param address	I2C bus address, or zero if set_address will be used
  	 */
  	I2C(const char *name,
  	    const char *devname,
  	    int bus,
  	    uint16_t address,
  	    uint32_t frequency = 0);
  	virtual ~I2C();
  
  	virtual int	init();
  
  	virtual ssize_t	read(file_t *handlep, char *buffer, size_t buflen);
  	virtual ssize_t	write(file_t *handlep, const char *buffer, size_t buflen);
  	virtual int	ioctl(file_t *handlep, int cmd, unsigned long arg);
  
  	/**
  	 * Perform an I2C transaction to the device.
  	 *
  	 * At least one of send_len and recv_len must be non-zero.
  	 *
  	 * @param send		Pointer to bytes to send.
  	 * @param send_len	Number of bytes to send.
  	 * @param recv		Pointer to buffer for bytes received.
  	 * @param recv_len	Number of bytes to receive.
  	 * @return		OK if the transfer was successful, -errno
  	 *			otherwise.
  	 */
  	int		transfer(const uint8_t *send, unsigned send_len,
  				 uint8_t *recv, unsigned recv_len);
  
  	/**
  	 * Perform a multi-part I2C transaction to the device.
  	 *
  	 * @param msgv		An I2C message vector.
  	 * @param msgs		The number of entries in the message vector.
  	 * @return		OK if the transfer was successful, -errno
  	 *			otherwise.
  	 */
  	int		transfer(struct i2c_msg *msgv, unsigned msgs);
  
  	/**
  	 * Change the bus address.
  	 *
  	 * Most often useful during probe() when the driver is testing
  	 * several possible bus addresses.
  	 *
  	 * @param address	The new bus address to set.
  	 */
  	void		set_address(uint16_t address)
  	{
  		_address = address;
  		_device_id.devid_s.address = _address;
  	}
  
  private:
  	uint16_t		_address;
  	int 			_fd;
  	std::string		_dname;
  
  	I2C(const device::I2C &);
  	I2C operator=(const device::I2C &);
  };
  
  } // namespace device
  
  #endif /* _DEVICE_I2C_H */
  