incubator-nuttx/drivers/i2c/i2c_write.c

93 lines
3.5 KiB
C

/****************************************************************************
* 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 <nuttx/config.h>
#include <assert.h>
#include <nuttx/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 */