text: /****************************************************************************
   *
   * Copyright 2016 Samsung Electronics All Rights Reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied. See the License for the specific
   * language governing permissions and limitations under the License.
   *
   ****************************************************************************/
  /****************************************************************************
   * drivers/i2c/i2c_write.c
   *
   *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *
   * 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 NuttX 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.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <tinyara/config.h>
  
  #include <assert.h>
  
  #include <tinyara/i2c.h>
  
  #if defined(CONFIG_I2C_TRANSFER)
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: i2c_write
   *
   * Description:
   *   Send a block of data on I2C. Each write operational will be an 'atomic'
   *   operation in the sense that any other I2C actions will be serialized
   *   and pend until this write completes.
   *
   * Input Parameters:
   *   dev    - Device-specific state data
   *   config  - Described the I2C configuration
   *   buffer - A pointer to the read-only buffer of data to be written to device
   *   buflen - The number of bytes to send from the buffer
   *
   * Returned Value:
   *   0: success, <0: A negated errno
   *
   ****************************************************************************/
  
  int i2c_write(FAR struct i2c_dev_s *dev, FAR const struct i2c_config_s *config, FAR const uint8_t *buffer, int buflen)
  {
  	struct i2c_msg_s msg;
  
  	/* Setup for the transfer */
  
  	msg.addr = config->address;
  	msg.flags = (config->addrlen == 10) ? I2C_M_TEN : 0;
  	msg.buffer = (FAR uint8_t *)buffer;	/* Override const */
  	msg.length = buflen;
  
  	/* Then perform the transfer
  	 *
  	 * REVISIT:  The following two operations must become atomic in order to
  	 * assure thread safety.
  	 */
  
  	I2C_SETFREQUENCY(dev, config->frequency);
  	return I2C_TRANSFER(dev, &msg, 1);
  }
  
  #endif							/* CONFIG_I2C_TRANSFER */
  