text: /****************************************************************************
   * boards/arm/lpc54xx/lpcxpresso-lpc54628/src/lpc54_buttons.c
   *
   *   Copyright (C) 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.
   *
   ****************************************************************************/
  
  /****************************************************************************
   * 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 "lpc54_gpio.h"
  #include "lpcxpresso-lpc54628.h"
  
  #include <arch/board/board.h>
  
  #ifdef CONFIG_ARCH_BUTTONS
  
  /****************************************************************************
   * Private Data
   ****************************************************************************/
  
  #if defined(CONFIG_LPC54_GPIOIRQ) && defined(CONFIG_ARCH_IRQBUTTONS)
  static uint8_t g_button_irq;
  static xcpt_t  g_button_handler;
  static void   *g_button_arg;
  #endif
  
  /****************************************************************************
   * Private Functions
   ****************************************************************************/
  
  /****************************************************************************
   * Name: board_button_interrupt
   *
   * Description:
   *   This function intermediates the interrupt provided to the application
   *   logic that attached the interrupt.  This is necessary to properly
   *   clear the pending button interrupts.
   *
   ****************************************************************************/
  
  static int board_button_interrupt(int irq, FAR void *context, FAR void *arg)
  {
    /* Acknowledge the button interrupt */
  
    lpc54_gpio_ackedge(irq);
  
    /* Transfer control to the attached interrupt handler */
  
    if (g_button_handler != NULL)
      {
        return g_button_handler(irq, context, arg);
      }
  
    return OK;
  }
  
  /****************************************************************************
   * 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 ret;
  
    /* Configure the button GPIO interrupt */
  
    ret = lpc54_gpio_config(GPIO_BUTTON_USER);
    if (ret >= 0)
      {
  #if defined(CONFIG_LPC54_GPIOIRQ) && defined(CONFIG_ARCH_IRQBUTTONS)
        /* Get the IRQ that is associated with the PIN interrupt and attach the
         * intermediate button interrupt handler to that interrupt.
         */
  
        g_button_irq = lpc54_gpio_irqno(GPIO_BUTTON_USER);
        irq_attach(g_button_irq, board_button_interrupt, NULL);
  #endif
      }
  
    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 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)
  {
    return lpc54_gpio_read(GPIO_BUTTON_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_AVR32_GPIOIRQ must be selected to enable the
   *   overall GPIO IRQ feature and CONFIG_AVR32_GPIOIRQSETA and/or
   *   CONFIG_AVR32_GPIOIRQSETB must be enabled to select GPIOs to support
   *   interrupts on.  For button support, bits 2 and 3 must be set in
   *   CONFIG_AVR32_GPIOIRQSETB (PB2 and PB3).
   *
   ****************************************************************************/
  
  #if defined(CONFIG_LPC54_GPIOIRQ) && defined(CONFIG_ARCH_IRQBUTTONS)
  int board_button_irq(int id, xcpt_t irqhandler, FAR void *arg)
  {
    int ret = -EINVAL;
  
    if (id == BUTTON_USER)
      {
        /* Are we attaching or detaching? */
  
        if (irqhandler != NULL)
          {
            /* Yes.. Attach and enable the interrupt */
  
            g_button_handler = irqhandler;
            g_button_arg     = arg;
            up_enable_irq(g_button_irq);
          }
        else
          {
            /* No.. Disable and detach the interrupt */
  
            up_disable_irq(g_button_irq);
            g_button_handler = NULL;
            g_button_arg     = NULL;
          }
  
        ret = OK;
      }
  
    return ret;
  }
  #endif
  
  #endif /* CONFIG_ARCH_BUTTONS */
  