text: /****************************************************************************
   * boards/arm/stm32/nucleo-f303re/src/stm32_buttons.c
   *
   *   Copyright (C) 2014-2015, 2017 Gregory Nutt. All rights reserved.
   *   Copyright (C) 2015 Omni Hoverboards Inc. All rights reserved.
   *   Authors: Gregory Nutt <gnutt@nuttx.org>
   *            Paul Alexander Patience <paul-a.patience@polymtl.ca>
   *
   * 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 <stdint.h>
  #include <stdbool.h>
  #include <errno.h>
  
  #include <nuttx/board.h>
  #include <arch/board/board.h>
  
  #include "stm32.h"
  #include "nucleo-f303re.h"
  
  #ifdef CONFIG_ARCH_BUTTONS
  
  /****************************************************************************
   * Public Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: board_button_initialize
   *
   * Description:
   *   board_button_initialize() must be called to initialize button
   *   resources.  After that, board_buttons() may be called to collect the
   *   current state of all buttons or board_button_irq() may be called to
   *   register button interrupt handlers.
   *
   ****************************************************************************/
  
  uint32_t board_button_initialize(void)
  {
    /* Configure the single button as an input.  NOTE that EXTI interrupts are
     * also configured for the pin.
     */
  
    stm32_configgpio(GPIO_BTN_USER);
    return NUM_BUTTONS;
  }
  
  /****************************************************************************
   * Name: board_buttons
   *
   * Description:
   *   After board_button_initialize() has been called, board_buttons() may be
   *   called to collect the state of all buttons.  board_buttons() returns an
   *   32-bit unsigned integer with each bit associated with a button.  See the
   *   BUTTON_*_BIT definitions in board.h for the meaning of each bit.
   *
   ****************************************************************************/
  
  uint32_t board_buttons(void)
  {
    /* Check the state of the USER button.  A LOW value means that the key is
     * pressed.
     */
  
    return stm32_gpioread(GPIO_BTN_USER) ? 0 : BUTTON_USER_BIT;
  }
  
  /****************************************************************************
   * Name: board_button_irq
   *
   * Description:
   *   board_button_irq() may be called to register an interrupt handler that
   *   will be called when a button is depressed or released.  The ID value is
   *   a button enumeration value that uniquely identifies a button resource.
   *   See the BUTTON_* definitions in board.h for the meaning of the
   *   enumeration value.
   *
   ****************************************************************************/
  
  #ifdef CONFIG_ARCH_IRQBUTTONS
  int board_button_irq(int id, xcpt_t irqhandler, FAR void *arg)
  {
    int ret = -EINVAL;
  
    if (id == BUTTON_USER)
      {
        ret = stm32_gpiosetevent(GPIO_BTN_USER, true, true, true, irqhandler,
                                 arg);
      }
  
    return ret;
  }
  #endif
  
  #endif /* CONFIG_ARCH_BUTTONS */
  