text: /****************************************************************************
   * configs/sama5d3-xplained/src/sam_buttons.c
   *
   *   Copyright (C) 2014-2015, 2017 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.
   *
   ****************************************************************************/
  /* There are five push button switches on the SAMA5D3-Xplained base board:
   *
   *   1. One Reset, board reset (BP1)
   *   2. One Wake up, push button to bring the processor out of low power mode
   *     (BP2)
   *   3. One User momentary Push Button
   *   4. One Disable CS Push Button
   *
   * Only the momentary push button is controllable by software (labeled
   * "PB_USER1" on the board):
   *
   *   - PE27.  Pressing the switch connect PE27 to grounded.  Therefore, PE27
   *     must be pulled high internally.  When the button is pressed the SAMA5
   *     will sense "0" is on PE27.
   */
  
  /****************************************************************************
   * Included Files
   ****************************************************************************/
  
  #include <nuttx/config.h>
  
  #include <stdint.h>
  #include <errno.h>
  
  #include <nuttx/arch.h>
  #include <nuttx/board.h>
  #include <nuttx/irq.h>
  
  #include <nuttx/irq.h>
  #include <arch/board/board.h>
  
  #include "sam_pio.h"
  #include "sama5d3-xplained.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.
   *
   ****************************************************************************/
  
  void board_button_initialize(void)
  {
    (void)sam_configpio(PIO_USER);
  }
  
  /****************************************************************************
   * 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
   *   8-bit bit set with each bit associated with a button.  See the BUTTON*
   *   definitions above for the meaning of each bit in the returned value.
   *
   ****************************************************************************/
  
  uint8_t board_buttons(void)
  {
    return sam_pioread(PIO_USER) ? 0 : BUTTON_USER_BIT;
  }
  
  /****************************************************************************
   * Name: board_button_irq
   *
   * Description:
   *   This function may be called to register an interrupt handler that will
   *   be called when a button is depressed or released.  The ID value is one
   *   of the BUTTON* definitions provided above.
   *
   * Configuration Notes:
   *   Configuration CONFIG_SAMA5_PIO_IRQ must be selected to enable the
   *   overall PIO IRQ feature and CONFIG_SAMA5_PIOE_IRQ must be enabled to
   *   select PIOs to support interrupts on PIOE.
   *
   ****************************************************************************/
  
  #if defined(CONFIG_SAMA5_PIOE_IRQ) && defined(CONFIG_ARCH_IRQBUTTONS)
  int board_button_irq(int id, xcpt_t irqhandler, FAR void *arg)
  {
    int ret = -EINVAL;
  
    if (id == BUTTON_USER)
      {
        irqstate_t flags;
  
        /* Disable interrupts until we are done.  This guarantees that the
         * following operations are atomic.
         */
  
        flags = enter_critical_section();
  
        /* Are we attaching or detaching? */
  
        if (irqhandler != NULL)
          {
            /* Configure the interrupt */
  
            sam_pioirq(PIO_USER);
            (void)irq_attach(IRQ_USER1, irqhandler, arg);
            sam_pioirqenable(IRQ_USER1);
          }
        else
          {
            /* Disable and detach the interrupt */
  
            sam_pioirqdisable(IRQ_USER1);
            (void)irq_detach(IRQ_USER1);
          }
  
        leave_critical_section(flags);
        ret = OK;
      }
  
    return ret;
  }
  #endif
  
  #endif /* CONFIG_ARCH_BUTTONS */
  