nuttx/configs/tm4c123g-launchpad/src/tm4c_buttons.c

/****************************************************************************
 * config/tm4c123g-launchpad/src/tm4c_buttons.c
 *
 *   Copyright (C) 2015, 2017 Gregory Nutt. All rights reserved.
 *   Author: Bradley Noyes <bradley.noyes@trd2inc.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 <errno.h>

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

#include "tiva_gpio.h"
#include "tm4c123g-launchpad.h"

#ifdef CONFIG_ARCH_BUTTONS

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

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

/****************************************************************************
 * 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.
 *
 ****************************************************************************/

void board_button_initialize(void)
{
  /* Unlock GPIOF from NMI to use it w/ buttons see Register 19 of GPIOs
   * and see table 10-10 in datasheet for pins with special considerations.
   */

  tiva_gpio_lockport(GPIO_SW2, false);

  /* Configure the GPIO pins as inputs.  NOTE that EXTI interrupts are
   * configured for some pins but NOT used in this file
   */

  tiva_configgpio(GPIO_SW1);
  tiva_configgpio(GPIO_SW2);

  /* These pins need to be set to logic high (3.3V) so that the buttons
   * can pull them to logic low (0V)
   */

  tiva_gpiowrite(GPIO_SW1, true);
  tiva_gpiowrite(GPIO_SW2, true);

  /* Configure GPIO interrupts */

#ifdef CONFIG_ARCH_IRQBUTTONS
  (void)tiva_gpioirqinitialize();
#endif
}

/****************************************************************************
 * 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 bit set with each bit associated with a button.  See the BUTTON*
 *   definitions above for the meaning of each bit in the returned value.
 *
 ****************************************************************************/

uint32_t board_buttons(void)
{
  uint32_t ret = 0;

  /* Check that state of each key.  A LOW value means that the key is
   * pressed.
   */

  if (!tiva_gpioread(GPIO_SW1))
    {
      ret |= BUTTON_SW1_BIT;
    }

  if (!tiva_gpioread(GPIO_SW2))
    {
      ret |= BUTTON_SW2_BIT;
    }

  return ret;
}

/****************************************************************************
 * 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.
 *
 ****************************************************************************/

#ifdef CONFIG_ARCH_IRQBUTTONS
int board_button_irq(int id, xcpt_t irqhandler, FAR void *arg)
{
  uint32_t pinset = 0;
  int ret;

  /* Determine which switch to set the irq handler for */

  switch (id)
    {
      case BUTTON_SW1:
        pinset = GPIO_SW1;
        break;

      case BUTTON_SW2:
        pinset = GPIO_SW2;
        break;

      default:
        return -EINVAL;
    }

    /* Are we attaching or detaching? */

    if (irqhandler != NULL)
      {
        ret = tiva_gpioirqattach(pinset, irqhandler, arg);
      }
    else
      {
        ret = tiva_gpioirqdetach(pinset);
      }

  return ret;
}
#endif

#endif /* CONFIG_ARCH_BUTTONS */