nuttx/configs/pic32mz-starterkit/src/pic32mz_buttons.c

/****************************************************************************
 * configs/pic32mz-starterkit/src/pic32mz_buttons.c
 *
 *   Copyright (C) 2015 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 <stdint.h>

#include <nuttx/arch.h>
#include <nuttx/board.h>
#include <arch/board/board.h>

#include "pic32mz-gpio.h"
#include "pic32mz-starterkit.h"

#ifdef CONFIG_ARCH_BUTTONS

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

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

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

/* Pin configuration for each start kit switch.  This array is indexed by
 * the BUTTON_* definitions in board.h
 */

static const pinset_t g_buttons[NUM_BUTTONS] =
{
  GPIO_SW_1, GPIO_SW_2, GPIO_SW_3
};

/****************************************************************************
 * 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)
{
  int i;

  /* Configure the GPIO pins as inputs.  NOTE that EXTI interrupts are
   * configured for all pins.
   */

  for (i = 0; i < NUM_BUTTONS; i++)
    {
      pic32mz_configgpio(g_buttons[i]);
    }
}

/****************************************************************************
 * Name: board_buttons
 ****************************************************************************/

uint8_t board_buttons(void)
{
  uint8_t ret = 0;
  int i;

  /* Check that state of each key */

  for (i = 0; i < NUM_BUTTONS; i++)
    {
       /* A LOW value means that the key is pressed. */

       bool released = pic32mz_gpioread(g_buttons[i]);

       /* Accumulate the set of depressed (not released) keys */

       if (!released)
         {
            ret |= (1 << i);
         }
    }

  return ret;
}

/*****************************************************************************
 * Button interrupt support.
 *
 * 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
 *   interrupthandlers.
 *
 *   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_*_BIT definitions in board.h for the meaning of each bit.
 *
 *   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 enumeration
 *   value.  The previous interrupt handler address is returned (so that it
 *   may restored, if so desired).
 *
 *****************************************************************************/

#ifdef CONFIG_ARCH_IRQBUTTONS
xcpt_t board_button_irq(int id, xcpt_t irqhandler)
{
#ifdef CONFIG_PIC32MZ_GPIOIRQ_PORTB
  xcpt_t oldhandler = NULL;

  if ((unsigned)id < NUM_BUTTONS)
    {
      /* Perform the attach/detach operation */

      oldhandler = pic32mz_gpioattach(g_buttons[id], irqhandler);

      /* The interrupt is now disabled.  Are we attaching or detaching from
       * button interrupt?
       */

      if (irqhandler)
        {
          /* Attaching... enable button interrupts now */

          pic32mz_gpioirqenable(g_buttons[id]);
        }
    }

  return oldhandler;
#else
  return NULL;
#endif
}
#endif
#endif /* CONFIG_ARCH_BUTTONS */