118 lines
4.2 KiB
C
118 lines
4.2 KiB
C
/****************************************************************************
|
|
* drivers/i2c/i2c_writeread.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/i2c_master.h>
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: i2c_writeread
|
|
*
|
|
* Description:
|
|
* Send a block of data on I2C followed by restarted read access. This
|
|
* provides a convenient wrapper to the transfer function.
|
|
*
|
|
* Input Parameters:
|
|
* dev - Device-specific state data
|
|
* config - Described the I2C configuration
|
|
* wbuffer - A pointer to the read-only buffer of data to be written to device
|
|
* wbuflen - The number of bytes to send from the buffer
|
|
* rbuffer - A pointer to a buffer of data to receive the data from the device
|
|
* rbuflen - The requested number of bytes to be read
|
|
*
|
|
* Returned Value:
|
|
* 0: success, <0: A negated errno
|
|
*
|
|
****************************************************************************/
|
|
|
|
int i2c_writeread(FAR struct i2c_master_s *dev,
|
|
FAR const struct i2c_config_s *config,
|
|
FAR const uint8_t *wbuffer, int wbuflen,
|
|
FAR uint8_t *rbuffer, int rbuflen)
|
|
{
|
|
struct i2c_msg_s msg[2];
|
|
unsigned int flags;
|
|
int ret;
|
|
|
|
/* 7- or 10-bit address? */
|
|
|
|
DEBUGASSERT(config->addrlen == 10 || config->addrlen == 7);
|
|
flags = (config->addrlen == 10) ? I2C_M_TEN : 0;
|
|
|
|
/* Format two messages: The first is a write which is never terminated
|
|
* with STOP condition.
|
|
*/
|
|
|
|
msg[0].frequency = config->frequency,
|
|
msg[0].addr = config->address;
|
|
msg[0].flags = flags | I2C_M_NOSTOP;
|
|
msg[0].buffer = (FAR uint8_t *)wbuffer; /* Override const */
|
|
msg[0].length = wbuflen;
|
|
|
|
/* The second is either a read (rbuflen > 0) with a repeated start or a
|
|
* write (rbuflen < 0) with no restart.
|
|
*/
|
|
|
|
if (rbuflen > 0)
|
|
{
|
|
msg[1].flags = (flags | I2C_M_READ);
|
|
}
|
|
else
|
|
{
|
|
msg[1].flags = (flags | I2C_M_NOSTART);
|
|
rbuflen = -rbuflen;
|
|
}
|
|
|
|
msg[1].frequency = config->frequency,
|
|
msg[1].addr = config->address;
|
|
msg[1].buffer = rbuffer;
|
|
msg[1].length = rbuflen;
|
|
|
|
/* Then perform the transfer. */
|
|
|
|
ret = I2C_TRANSFER(dev, msg, 2);
|
|
return (ret >= 0) ? OK : ret;
|
|
}
|