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