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RIOT/drivers/pir/pir.c 2.95 KB
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  /*
   * Copyright (C) 2014 Freie Universität Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     drivers_pir
   * @{
   *
   * @file
   * @brief       Device driver implementation for the PIR motion sensor
   *
   * @author      Ludwig Knüpfer <ludwig.knuepfer@fu-berlin.de>
   *
   * @}
   */
  
  #include "pir.h"
  #include "thread.h"
  #include "msg.h"
  
  #define ENABLE_DEBUG (0)
  #include "debug.h"
  
  /**********************************************************************
   * internal API declaration
   **********************************************************************/
  
  static int pir_activate_int(pir_t *dev);
  static void pir_callback(void *dev);
  static void pir_send_msg(pir_t *dev, pir_event_t event);
  
  /**********************************************************************
   * public API implementation
   **********************************************************************/
  
  int pir_init(pir_t *dev, gpio_t gpio)
  {
      dev->gpio_dev = gpio;
      dev->msg_thread_pid = KERNEL_PID_UNDEF;
      return gpio_init(dev->gpio_dev, GPIO_IN);
  }
  
  pir_event_t pir_get_status(const pir_t *dev)
  {
      return ((gpio_read(dev->gpio_dev) == 0) ? PIR_STATUS_LO : PIR_STATUS_HI);
  }
  
  int pir_register_thread(pir_t *dev)
  {
      if (dev->msg_thread_pid != KERNEL_PID_UNDEF) {
          if (dev->msg_thread_pid != thread_getpid()) {
              DEBUG("pir_register_thread: already registered to another thread\n");
              return -2;
          }
      }
      else {
          DEBUG("pir_register_thread: activating interrupt for %p..\n", (void *)dev);
          if (pir_activate_int(dev) != 0) {
              DEBUG("\tfailed\n");
              return -1;
          }
          DEBUG("\tsuccess\n");
      }
      dev->msg_thread_pid = thread_getpid();
  
      return 0;
  }
  
  /**********************************************************************
   * internal API implementation
   **********************************************************************/
  
  static void pir_send_msg(pir_t *dev, pir_event_t event)
  {
      DEBUG("pir_send_msg\n");
      msg_t m = { .type = event, .content.ptr = dev, };
  
      int ret = msg_send_int(&m, dev->msg_thread_pid);
      DEBUG("pir_send_msg: msg_send_int: %i\n", ret);
      switch (ret) {
          case 0:
              DEBUG("pir_send_msg: msg_thread_pid not receptive, event is lost");
              break;
          case 1:
              DEBUG("pir_send_msg: OK");
              break;
          case -1:
              DEBUG("pir_send_msg: msg_thread_pid is gone, clearing it");
              dev->msg_thread_pid = KERNEL_PID_UNDEF;
              break;
      }
      DEBUG("\n");
  }
  
  static void pir_callback(void *arg)
  {
      DEBUG("pir_callback: %p\n", arg);
      pir_t *dev = (pir_t*) arg;
      if (dev->msg_thread_pid != KERNEL_PID_UNDEF) {
          pir_send_msg(dev, pir_get_status(dev));
      }
  }
  
  static int pir_activate_int(pir_t *dev)
  {
      return gpio_init_int(dev->gpio_dev, GPIO_IN, GPIO_BOTH, pir_callback, dev);
  }