nuttx/boards/arm/sama5/sama5d4-ek/src/sam_audio_null.c

/****************************************************************************
 * boards/arm/sama5/sama5d4-ek/src/sam_audio_null.c
 *
 *   Copyright (C) 2014 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 <stdbool.h>
#include <stdio.h>
#include <debug.h>
#include <assert.h>
#include <errno.h>

#include <nuttx/audio/audio.h>
#include <nuttx/audio/pcm.h>
#include <nuttx/audio/audio_null.h>

#include "sama5d4-ek.h"

#ifdef HAVE_AUDIO_NULL

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

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

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

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

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

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

/****************************************************************************
 * Name: sam_audio_null_initialize
 *
 * Description:
 *   Set up to use the NULL audio device for PCM unit-level testing.
 *
 * Input Parameters:
 *   minor - The input device minor number
 *
 * Returned Value:
 *   Zero is returned on success.  Otherwise, a negated errno value is
 *   returned to indicate the nature of the failure.
 *
 ****************************************************************************/

int sam_audio_null_initialize(int minor)
{
  FAR struct audio_lowerhalf_s *nullaudio;
  FAR struct audio_lowerhalf_s *pcm;
  static bool initialized = false;
  char devname[12];
  int ret;

  audinfo("minor %d\n", minor);
  DEBUGASSERT(minor >= 0 && minor <= 25);

  /* Have we already initialized?  Since we never uninitialize we must prevent
   * multiple initializations.  This is necessary, for example, when the
   * touchscreen example is used as a built-in application in NSH and can be
   * called numerous time.  It will attempt to initialize each time.
   */

  if (!initialized)
    {
      /* Get a null audio interface
       */

      nullaudio = audio_null_initialize();
      if (!nullaudio)
        {
          auderr("ERROR: Failed to get the NULL audio interface\n");
          ret = -ENODEV;
          goto errout;
        }

      /* No we can embed the null audio interface into a PCM decoder
       * instance so that we will have a PCM front end for the NULL
       * audio driver.
       */

      pcm = pcm_decode_initialize(nullaudio);
      if (!pcm)
        {
          auderr("ERROR: Failed create the PCM decoder\n");
          ret = -ENODEV;
          goto errout_with_nullaudio;
        }

      /* Create a device name */

      snprintf(devname, 12, "pcm%d",  minor);

      /* Finally, we can register the PCM/NULL audio device. */

      ret = audio_register(devname, pcm);
      if (ret < 0)
        {
          auderr("ERROR: Failed to register /dev/%s device: %d\n",
                 devname, ret);
          goto errout_with_pcm;
        }

      /* Now we are initialized */

      initialized = true;
    }

  return OK;

  /* Error exits.  Unfortunately there is no mechanism in place now to
   * recover resources from most errors on initialization failures.
   */

errout_with_nullaudio:
errout_with_pcm:
errout:
  return ret;
}

#endif /* HAVE_AUDIO_NULL */