nuttx/configs/samd21-xplained/src/sam_buttons.c

/****************************************************************************
 * configs/samd21-xplained/src/sam_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 <nuttx/irq.h>

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

#include "sam_port.h"
#include "samd21-xplained.h"

#ifdef CONFIG_ARCH_BUTTONS

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

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

#if defined(CONFIG_PORTA_IRQ) && defined(CONFIG_ARCH_IRQBUTTONS)
static xcpt_t g_irqsw0;
#endif

/****************************************************************************
 * 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)
{
  (void)sam_configport(PORT_SW0);
}

/************************************************************************************
 * 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_portread(PORT_SW0) ? 0 : BUTTON_SW0_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. The previous interrupt
 *   handler address isreturned (so that it may restored, if so desired).
 *
 * Configuration Notes:
 *   Configuration CONFIG_AVR32_PORTIRQ must be selected to enable the
 *   overall PORT IRQ feature and CONFIG_AVR32_PORTIRQSETA and/or
 *   CONFIG_AVR32_PORTIRQSETB must be enabled to select PORTs to support
 *   interrupts on.  For button support, bits 2 and 3 must be set in
 *   CONFIG_AVR32_PORTIRQSETB (PB2 and PB3).
 *
 ****************************************************************************/

#if defined(CONFIG_PORTA_IRQ) && defined(CONFIG_ARCH_IRQBUTTONS)
xcpt_t board_button_irq(int id, xcpt_t irqhandler)
{
  xcpt_t oldhandler = NULL;

  if (id == BUTTON_SW0)
    {
      irqstate_t flags;

      /* Disable interrupts until we are done.  This guarantees that the
       * following operations are atomic.
       */

      flags = irqsave();

      /* Get the old button interrupt handler and save the new one */

      oldhandler = *g_irqsw0;
      *g_irqsw0 = irqhandler;

      /* Configure the interrupt */

      sam_portirq(IRQ_SW0);
      (void)irq_attach(IRQ_SW0, irqhandler);
      sam_portirqenable(IRQ_SW0);
      irqrestore(flags);
    }

  /* Return the old button handler (so that it can be restored) */

  return oldhandler;
}
#endif

#endif /* CONFIG_ARCH_BUTTONS */