nuttx/drivers/1wire/1wire_write.c

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/****************************************************************************
* drivers/1wire/1wire_write.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <assert.h>
#include <nuttx/1wire/1wire.h>
#include <nuttx/1wire/1wire_master.h>
#include "1wire_internal.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: 1wire_write
*
* Description:
* Send a block of data on 1WIRE. Each write operation will be an 'atomic'
* operation in the sense that any other 1WIRE actions will be serialized
* and pend until this write completes.
*
* Input Parameters:
* master - Device-specific state data
* config - Described the 1WIRE 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 onewire_write(FAR struct onewire_master_s *master,
FAR const struct onewire_config_s *config,
FAR const uint8_t *buffer, int buflen)
{
int ret;
/* Avoid calling this function from a search callback to prevent a
* deadlock
*/
if (master->insearch == true)
{
return -EAGAIN;
}
ret = onewire_sem_wait(master);
if (ret < 0)
{
return ret;
}
ret = onewire_reset_select(master, config->romcode);
if (ret < 0)
{
goto err_unlock;
}
/* Then perform the transfer. */
ret = ONEWIRE_WRITE(master->dev, buffer, buflen);
err_unlock:
onewire_sem_post(master);
return ret;
}