examples/leds/leds_main.c

/****************************************************************************
 * examples/leds/leds_main.c
 *
 *   Copyright (C) 2016 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/ioctl.h>
#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <fcntl.h>
#include <sched.h>
#include <errno.h>

#include <nuttx/leds/userled.h>

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

static bool g_led_daemon_started;

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

/****************************************************************************
 * Name: led_daemon
 ****************************************************************************/

static int led_daemon(int argc, char *argv[])
{
  userled_set_t supported;
  userled_set_t ledset;
  bool incrementing;
  int ret;
  int fd;

  /* Indicate that we are running */

  g_led_daemon_started = true;
  printf("led_daemon: Running\n");

  /* Open the LED driver */

  printf("led_daemon: Opening %s\n", CONFIG_EXAMPLES_LEDS_DEVPATH);
  fd = open(CONFIG_EXAMPLES_LEDS_DEVPATH, O_WRONLY);
  if (fd < 0)
    {
      int errcode = errno;
      printf("led_daemon: ERROR: Failed to open %s: %d\n",
             CONFIG_EXAMPLES_LEDS_DEVPATH, errcode);
      goto errout;
    }

  /* Get the set of LEDs supported */

  ret = ioctl(fd, ULEDIOC_SUPPORTED,
              (unsigned long)((uintptr_t)&supported));
  if (ret < 0)
    {
      int errcode = errno;
      printf("led_daemon: ERROR: ioctl(ULEDIOC_SUPPORTED) failed: %d\n",
             errcode);
      goto errout_with_fd;
    }

  /* Excluded any LEDs that not supported AND not in the set of LEDs the
   * user asked us to use.
   */

  printf("led_daemon: Supported LEDs 0x%02x\n", (unsigned int)supported);
  supported &= CONFIG_EXAMPLES_LEDS_LEDSET;

  /* Now loop forever, changing the LED set */

  ledset       = 0;
  incrementing = true;

  for (; ; )
    {
      userled_set_t newset;
      userled_set_t tmp;

      if (incrementing)
        {
          tmp = ledset;
          do
            {
              tmp++;
              newset = tmp & supported;
            }
          while (newset == ledset);

          /* REVISIT: There are flaws in this logic.  It would not work
           * correctly if there were spaces in the supported mask.
           */

          if (newset == 0)
            {
              incrementing = false;
              continue;
            }
        }
      else
        {
          /* REVISIT: There are flaws in this logic.  It would not work
           * correctly if there were spaces in the supported mask.
           */

          if (ledset == 0)
            {
              incrementing = true;
              continue;
            }

          tmp = ledset;
          do
            {
              tmp--;
              newset = tmp & supported;
            }
          while (newset == ledset);
        }

      ledset = newset;
      printf("led_daemon: LED set 0x%02x\n", (unsigned int)ledset);

      ret = ioctl(fd, ULEDIOC_SETALL, ledset);
      if (ret < 0)
        {
          int errcode = errno;
          printf("led_daemon: ERROR: ioctl(ULEDIOC_SUPPORTED) failed: %d\n",
                 errcode);
          goto errout_with_fd;
        }

      usleep(500*1000L);
    }

errout_with_fd:
  close(fd);

errout:
  g_led_daemon_started = false;

  printf("led_daemon: Terminating\n");
  return EXIT_FAILURE;
}

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

/****************************************************************************
 * leds_main
 ****************************************************************************/

int main(int argc, FAR char *argv[])
{
  int ret;

  printf("leds_main: Starting the led_daemon\n");
  if (g_led_daemon_started)
    {
      printf("leds_main: led_daemon already running\n");
      return EXIT_SUCCESS;
    }

  ret = task_create("led_daemon", CONFIG_EXAMPLES_LEDS_PRIORITY,
                    CONFIG_EXAMPLES_LEDS_STACKSIZE, led_daemon,
                    NULL);
  if (ret < 0)
    {
      int errcode = errno;
      printf("leds_main: ERROR: Failed to start led_daemon: %d\n",
             errcode);
      return EXIT_FAILURE;
    }

  printf("leds_main: led_daemon started\n");
  return EXIT_SUCCESS;
}