text: /****************************************************************************
   * arch/arm/src/stm32f7/stm32_exti_wakeup.c
   *
   *   Copyright (C) 2009, 2012, 2017-2018 Gregory Nutt. All rights reserved.
   *   Author: Gregory Nutt <gnutt@nuttx.org>
   *           Juha Niskanen <juha.niskanen@haltian.com>
   *
   * 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 <nuttx/irq.h>
  #include <nuttx/arch.h>
  
  #include <stdint.h>
  #include <stdbool.h>
  #include <errno.h>
  
  #include <arch/irq.h>
  
  #include "arm_arch.h"
  #include "chip.h"
  #include "stm32_gpio.h"
  #include "stm32_exti.h"
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  /* Interrupt handlers attached to the RTC WAKEUP EXTI */
  
  static xcpt_t g_wakeup_callback;
  static void  *g_callback_arg;
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: stm32_exti_wakeup_isr
   *
   * Description:
   *   EXTI periodic WAKEUP interrupt service routine/dispatcher
   *
   ****************************************************************************/
  
  static int stm32_exti_wakeup_isr(int irq, void *context, FAR void *arg)
  {
    int ret = OK;
  
    /* Dispatch the interrupt to the handler */
  
    if (g_wakeup_callback != NULL)
      {
        ret = g_wakeup_callback(irq, context, g_callback_arg);
      }
  
    /* Clear the pending EXTI interrupt */
  
    putreg32(EXTI_RTC_WAKEUP, STM32_EXTI_PR);
  
    return ret;
  }
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: stm32_exti_wakeup
   *
   * Description:
   *   Sets/clears EXTI wakeup interrupt.
   *
   * Input Parameters:
   *  - rising/falling edge: enables interrupt on rising/falling edges
   *  - event:  generate event when set
   *  - func:   when non-NULL, generate interrupt
   *
   * Returned Value:
   *   Zero (OK) on success; a negated errno value on failure indicating the
   *   nature of the failure.
   *
   ****************************************************************************/
  
  int stm32_exti_wakeup(bool risingedge, bool fallingedge, bool event,
                        xcpt_t func, void *arg)
  {
    g_wakeup_callback = func;
    g_callback_arg    = arg;
  
    /* Install external interrupt handlers (if not already attached) */
  
    if (func)
      {
        irq_attach(STM32_IRQ_RTC_WKUP, stm32_exti_wakeup_isr, NULL);
        up_enable_irq(STM32_IRQ_RTC_WKUP);
      }
    else
      {
        up_disable_irq(STM32_IRQ_RTC_WKUP);
      }
  
    /* Configure rising/falling edges */
  
    modifyreg32(STM32_EXTI_RTSR,
                risingedge ? 0 : EXTI_RTC_WAKEUP,
                risingedge ? EXTI_RTC_WAKEUP : 0);
    modifyreg32(STM32_EXTI_FTSR,
                fallingedge ? 0 : EXTI_RTC_WAKEUP,
                fallingedge ? EXTI_RTC_WAKEUP : 0);
  
    /* Enable Events and Interrupts */
  
    modifyreg32(STM32_EXTI_EMR,
                event ? 0 : EXTI_RTC_WAKEUP,
                event ? EXTI_RTC_WAKEUP : 0);
    modifyreg32(STM32_EXTI_IMR,
                func ? 0 : EXTI_RTC_WAKEUP,
                func ? EXTI_RTC_WAKEUP : 0);
  
    return OK;
  }
  