nuttx/boards/arm/tiva/dk-tm4c129x/src/tm4c_buttons.c

/****************************************************************************
 * boards/arm/tiva/dk-tm4c/src/tm4c_buttons.c
 *
 *   Copyright (C) 2014-2015 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 <errno.h>

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

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

#include "dk-tm4c129x.h"

#ifdef CONFIG_ARCH_BUTTONS

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

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

/* Pin configuration for each STM3210E-EVAL button.  This array is indexed by
 * the BUTTON_* and JOYSTICK_* definitions in board.h
 */

static const uint32_t g_buttons[NUM_BUTTONS] =
{
  GPIO_SW2, GPIO_SW3, GPIO_SW4
};

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

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

  /* Configure the GPIO pins as inputs. */

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

  return NUM_BUTTONS;
}

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

uint32_t board_buttons(void)
{
  uint32_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 = tiva_gpioread(g_buttons[i]);

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

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

  return ret;
}

/****************************************************************************
 * Button 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
 *   interrupt handlers.
 *
 *   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 bit set with each bit associated with
 *   a button.
 *   See the BUTTON_*_BIT and JOYSTICK_*_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_* and JOYSTICK_* definitions in board.h for the meaning
 *   of enumeration value.
 *
 ****************************************************************************/

#if defined(CONFIG_ARCH_IRQBUTTONS) && defined(CONFIG_TIVA_GPIOP_IRQS)
int board_button_irq(int id, xcpt_t irqhandler, FAR void *arg)
{
  irqstate_t flags;
  int ret = -EINVAL;

  /* Interrupts are supported only on ports P and Q and,
   * hence, only on button SW4
   */

  if (id == BUTTON_SW4)
    {
      /* The following should be atomic */

      flags = enter_critical_section();

      /* Detach and disable the button interrupt */

      up_disable_irq(IRQ_SW4);
      irq_detach(IRQ_SW4);

      /* Attach the new handler if so requested */

      if (irqhandler != NULL)
        {
          ret = irq_attach(IRQ_SW4, irqhandler, arg);
          if (ret == OK)
            {
              up_enable_irq(IRQ_SW4);
            }
        }

      leave_critical_section(flags);
    }

  return ret;
}
#endif
#endif /* CONFIG_ARCH_BUTTONS */