nuttx-apps/examples/i2schar/i2schar_transmitter.c

/****************************************************************************
 * examples/i2schar/i2schar_transmitter.c
 *
 *   Copyright (C) 2013 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 <sys/types.h>
#include <stdio.h>
#include <fcntl.h>
#include <pthread.h>
#include <errno.h>
#include <debug.h>

#include <nuttx/audio/audio.h>

#include "i2schar.h"

#ifdef CONFIG_EXAMPLES_I2SCHAR_TX

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Types
 ****************************************************************************/

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Public Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: i2schar_transmitter()
 *
 * Description:
 *   This is the entry point for the transmitter thread.
 *
 ****************************************************************************/

pthread_addr_t i2schar_transmitter(pthread_addr_t arg)
{
  FAR struct ap_buffer_s *apb;
  struct audio_buf_desc_s desc;
  uint8_t crap;
  uint8_t *ptr;
  int bufsize;
  int nwritten;
  int fd;
  int i;
  int j;

  /* Open the I2C character device */

  fd = open(g_i2schar.devpath, O_WRONLY);
  if (fd < 0)
    {
      int errcode = errno;
      message("i2schar_transmitter: ERROR: failed to open %s: %d\n",
              g_i2schar.devpath, errcode);
      pthread_exit(NULL);
    }

  /* Loop for the requested number of times */

  for (i = 0, crap = 0; i < CONFIG_EXAMPLES_I2SCHAR_TXBUFFERS; i++)
    {
      /* Allocate an audio buffer of the configured size */
 
      desc.numbytes   = CONFIG_EXAMPLES_I2SCHAR_BUFSIZE;
      desc.u.ppBuffer = &apb;

      bufsize = apb_alloc(&desc);
      if (bufsize < 0)
        {
           message("i2schar_transmitter: ERROR: failed to allocate buffer %d: %d\n",
                   i+1, bufsize);
           close(fd);
           pthread_exit(NULL);
        }

      /* Fill the audio buffer with crap */

      for (j = 0, ptr = apb->samp; j < CONFIG_EXAMPLES_I2SCHAR_BUFSIZE; j++)
        {
          *ptr++ = crap++;
        }

      /* Then send the buffer */

      do
        {
          /* Flush any output before writing */

          msgflush();

          /* Write the buffer to the I2S character driver */

          nwritten = write(fd, apb, bufsize);
          if (nwritten < 0)
            {
              int errcode = errno;
              if (errcode != EINTR)
                {
                  message("i2schar_transmitter: ERROR: write failed: %d\n",
                          errcode);
                  close(fd);
                  pthread_exit(NULL);
                }
            }
          else if (nwritten != bufsize)
            {
              message("i2schar_transmitter: ERROR: partial write: %d\n",
                      nwritten);
              close(fd);
              pthread_exit(NULL);
            }
          else
            {
              message("i2schar_transmitter: Send buffer %d\n", i+1);
            }
        }
      while (nwritten != bufsize);

      /* Make sure that the receiver thread has a chance to run */

      pthread_yield();
    }

  close(fd);
  return NULL;
}

#endif /* CONFIG_EXAMPLES_I2SCHAR_TX */