92 lines
2.8 KiB
C
92 lines
2.8 KiB
C
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/****************************************************************************
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* drivers/1wire/1wire_read.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <assert.h>
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#include <nuttx/1wire/1wire.h>
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#include <nuttx/1wire/1wire_master.h>
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#include "1wire_internal.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: 1wire_read
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*
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* Description:
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* Receive a block of data from 1WIRE. Each read operation will be an
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* 'atomic' operation in the sense that any other 1WIRE actions will be
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* serialized and pend until this read completes.
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*
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* Input Parameters:
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* master - Device-specific state data
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* buffer - A pointer to a buffer of data to receive the data from the
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* device
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* buflen - The requested number of bytes to be read
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*
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* Returned Value:
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* 0: success, <0: A negated errno
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*
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****************************************************************************/
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int onewire_read(FAR struct onewire_master_s *master,
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FAR const struct onewire_config_s *config,
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FAR uint8_t *buffer, int buflen)
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{
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int ret;
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/* Avoid calling this function from a search callback to prevent a
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* deadlock
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*/
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if (master->insearch == true)
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{
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return -EAGAIN;
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}
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ret = onewire_sem_wait(master);
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if (ret < 0)
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{
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return ret;
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}
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ret = onewire_reset_select(master, config->romcode);
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if (ret < 0)
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{
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goto err_unlock;
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}
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/* Then perform the transfer. */
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ret = ONEWIRE_READ(master->dev, buffer, buflen);
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err_unlock:
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onewire_sem_post(master);
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return ret;
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}
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