340 lines
9.5 KiB
C
340 lines
9.5 KiB
C
/****************************************************************************
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* drivers/rmt/rmtchar.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 <sys/types.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <string.h>
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#include <assert.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/kmalloc.h>
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#include <nuttx/mm/circbuf.h>
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#include <nuttx/mutex.h>
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#include <nuttx/rmt/rmt.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define DEVNAME_FMT "/dev/rmt%d"
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#define DEVNAME_FMTLEN (8 + 3 + 1)
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/****************************************************************************
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* Private Types
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****************************************************************************/
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struct rmt_driver_s
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{
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/* The lower half RMT driver */
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FAR struct rmt_dev_s *rmt;
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/* The minor identification of the driver. It's provided by the lower half
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* driver and it can represent the channel being used.
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*/
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int minor;
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mutex_t lock; /* Assures mutually exclusive access */
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};
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/****************************************************************************
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* Private Function Prototypes
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****************************************************************************/
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static int rmt_open(FAR struct file *filep);
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static int rmt_close(FAR struct file *filep);
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static ssize_t rmt_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen);
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static ssize_t rmt_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen);
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/****************************************************************************
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* Private Data
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****************************************************************************/
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static const struct file_operations g_rmt_channel_fops =
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{
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rmt_open, /* open */
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rmt_close, /* close */
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rmt_read, /* read */
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rmt_write, /* write */
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NULL, /* seek */
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NULL, /* ioctl */
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};
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: rmt_open
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*
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* Description:
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* Prepare the RMT peripheral for use. This method just calls the lower
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* half `open` routine if it exists.
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*
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* Input Parameters:
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* filep - Pointer system file data
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*
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* Returned Value:
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* The return code of the lower half `open` routine if it exists.
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* Please check device-specific driver for more information.
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*
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****************************************************************************/
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static int rmt_open(FAR struct file *filep)
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{
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FAR struct inode *inode;
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FAR struct rmt_driver_s *priv;
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int ret = OK;
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/* Get our private data structure */
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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if (priv->rmt->ops->open)
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{
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ret = priv->rmt->ops->open(priv->rmt);
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}
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return ret;
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}
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/****************************************************************************
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* Name: rmt_close
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*
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* Description:
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* Close the RMT peripheral after use. This method just calls the lower
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* half `close` routine if it exists.
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*
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* Input Parameters:
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* filep - Pointer system file data
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*
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* Returned Value:
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* The return code of the lower half `close` routine if it exists.
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* Please check device-specific driver for more information.
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*
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****************************************************************************/
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static int rmt_close(FAR struct file *filep)
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{
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FAR struct inode *inode;
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FAR struct rmt_driver_s *priv;
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int ret = OK;
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/* Get our private data structure */
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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if (priv->rmt->ops->close)
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{
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ret = priv->rmt->ops->close(priv->rmt);
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}
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return ret;
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}
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/****************************************************************************
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* Name: rmt_read
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*
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* Description:
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* This function reads data from the RMT device into the provided buffer.
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* The read operation is performed by the read function pointer in the
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* RMT device's operations structure, if it exists.
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*
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* Input Parameters:
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* filep - Pointer to the file structure.
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* buffer - Pointer to the buffer where the read data should be stored.
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* buflen - The maximum amount of data to be read.
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*
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* Returned Value:
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* Returns the number of bytes read from the RMT device; a negated errno
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* value is returned on any failure.
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*
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****************************************************************************/
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static ssize_t rmt_read(FAR struct file *filep, FAR char *buffer,
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size_t buflen)
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{
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FAR struct inode *inode;
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FAR struct rmt_driver_s *priv;
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ssize_t nread = 0;
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/* Get our private data structure */
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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if (priv->rmt->ops->read)
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{
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int ret = priv->rmt->ops->read(priv->rmt, buffer, buflen);
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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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for (; ; )
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{
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nread = circbuf_read(priv->rmt->circbuf , buffer, buflen);
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if (nread != 0 || (filep->f_oflags & O_NONBLOCK))
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{
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break;
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}
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while (circbuf_is_empty(priv->rmt->circbuf))
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{
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nxsem_wait_uninterruptible(priv->rmt->recvsem);
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}
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}
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}
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return nread;
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}
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/****************************************************************************
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* Name: rmt_write
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*
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* Description:
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* Write to the RMT peripheral. This method just calls the lower half
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* `write` routine if it exists.
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*
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* Input Parameters:
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* filep - Pointer system file data
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* buffer - Data to write to the RMT device
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* buflen - Number of bytes requested to write
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*
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* Returned Value:
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* Number of bytes that has been successfully written, or 0 when no
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* bytes could be written for any reason.
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*
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****************************************************************************/
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static ssize_t rmt_write(FAR struct file *filep, FAR const char *buffer,
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size_t buflen)
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{
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FAR struct inode *inode;
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FAR struct rmt_driver_s *priv;
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ssize_t nwritten = 0;
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/* Get our private data structure */
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inode = filep->f_inode;
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priv = inode->i_private;
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DEBUGASSERT(priv);
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if (priv->rmt->ops->write)
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{
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nwritten = priv->rmt->ops->write(priv->rmt, buffer, buflen);
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}
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return nwritten;
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: rmtchar_register
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*
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* Description:
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* Create and register the RMT character driver.
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*
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* The RMT character driver is a simple character driver that supports RMT
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* transfers via read() and write(). This driver is primarily intended to
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* support RMT testing. It is not suitable for use in any real driver
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* application in its current form because its buffer management heuristics
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* are dependent on the lower half driver (device-specific).
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*
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* Input Parameters:
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* rmt - An instance of the lower half RMT driver
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*
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* Returned Value:
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* OK if the driver was successfully registered; A negated errno value is
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* returned on any failure.
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*
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****************************************************************************/
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int rmtchar_register(FAR struct rmt_dev_s *rmt)
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{
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FAR struct rmt_driver_s *priv;
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char devname[DEVNAME_FMTLEN];
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size_t dev_size = sizeof(struct rmt_driver_s);
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int ret;
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/* Sanity check */
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DEBUGASSERT(rmt != NULL && (unsigned)rmt->minor < 1000);
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/* Allocate a RMT character device structure */
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priv = kmm_zalloc(dev_size);
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if (priv)
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{
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/* Initialize the RMT character device structure */
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priv->rmt = rmt;
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priv->minor = rmt->minor;
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nxmutex_init(&priv->lock);
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/* Create the character device name */
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snprintf(devname, sizeof(devname), DEVNAME_FMT, priv->minor);
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ret = register_driver(devname, &g_rmt_channel_fops, 0666, priv);
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if (ret < 0)
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{
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/* Free the device structure if we failed to create the character
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* device.
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*/
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nxmutex_destroy(&priv->lock);
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kmm_free(priv);
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return ret;
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}
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/* Return the result of the registration */
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return ret;
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}
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return -ENOMEM;
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}
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