nuttx/drivers/input/button_lower.c

/****************************************************************************
 * drivers/input/button_lower.c
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <assert.h>
#include <debug.h>
#include <inttypes.h>

#include <nuttx/board.h>
#include <nuttx/input/buttons.h>

#include <nuttx/irq.h>

#if CONFIG_INPUT_BUTTONS_LOWER

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static btn_buttonset_t
btn_supported(FAR const struct btn_lowerhalf_s *lower);
static btn_buttonset_t btn_buttons(FAR const struct btn_lowerhalf_s *lower);
static void btn_enable(FAR const struct btn_lowerhalf_s *lower,
                       btn_buttonset_t press, btn_buttonset_t release,
                       btn_handler_t handler, FAR void *arg);

static void btn_disable(void);
static int btn_interrupt(int irq, FAR void *context, FAR void *arg);

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

static uint32_t g_btnnum;

/* This is the button button lower half driver interface */

static const struct btn_lowerhalf_s g_btnlower =
{
  btn_supported,        /* bl_supported */
  btn_buttons,          /* bl_buttons */
  btn_enable,           /* bl_enable */
  NULL                  /* bl_write */
};

/* Current interrupt handler and argument */

static btn_handler_t g_btnhandler;
static FAR void *g_btnarg;

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

/****************************************************************************
 * Name: btn_supported
 *
 * Description:
 *   Return the set of buttons supported
 *
 ****************************************************************************/

static btn_buttonset_t btn_supported(FAR const struct btn_lowerhalf_s *lower)
{
  iinfo("NUM_BUTTONS: %02" PRIx32 "\n", g_btnnum);
  return (btn_buttonset_t)((1 << g_btnnum) - 1);
}

/****************************************************************************
 * Name: btn_buttons
 *
 * Description:
 *   Return the current state of button data
 *
 ****************************************************************************/

static btn_buttonset_t btn_buttons(FAR const struct btn_lowerhalf_s *lower)
{
  return board_buttons();
}

/****************************************************************************
 * Name: btn_enable
 *
 * Description:
 *   Enable interrupts on the selected set of buttons.  And empty set or
 *   a NULL handler will disable all interrupts.
 *
 ****************************************************************************/

static void btn_enable(FAR const struct btn_lowerhalf_s *lower,
                       btn_buttonset_t press, btn_buttonset_t release,
                       btn_handler_t handler, FAR void *arg)
{
  btn_buttonset_t mask;
  btn_buttonset_t either = press | release;
  irqstate_t flags;
  uint32_t id;

  /* Start with all interrupts disabled */

  flags = enter_critical_section();
  btn_disable();

  iinfo("press: %02" PRIx32 " release: %02" PRIx32 " handler: %p arg: %p\n",
        press, release, handler, arg);

  /* If no events are indicated or if no handler is provided, then this
   * must really be a request to disable interrupts.
   */

  if (either && handler)
    {
      /* Save the new the handler and argument */

      g_btnhandler = handler;
      g_btnarg     = arg;

      /* Attach and enable each button interrupt */

      for (id = 0; id < g_btnnum; id++)
        {
          mask = (1 << id);
          if ((either & mask) != 0)
            {
              board_button_irq(id, btn_interrupt, NULL);
            }
        }
    }

  leave_critical_section(flags);
}

/****************************************************************************
 * Name: btn_disable
 *
 * Description:
 *   Disable all button interrupts
 *
 ****************************************************************************/

static void btn_disable(void)
{
  irqstate_t flags;
  uint32_t id;

  /* Disable each button interrupt */

  flags = enter_critical_section();
  for (id = 0; id < g_btnnum; id++)
    {
      board_button_irq(id, NULL, NULL);
    }

  /* Nullify the handler and argument */

  g_btnhandler = NULL;
  g_btnarg     = NULL;
  leave_critical_section(flags);
}

/****************************************************************************
 * Name: btn_interrupt
 *
 * Description:
 *   Discrete button interrupt handler (all buttons)
 *
 ****************************************************************************/

static int btn_interrupt(int irq, FAR void *context, FAR void *arg)
{
  DEBUGASSERT(g_btnhandler);

  if (g_btnhandler)
    {
      g_btnhandler(&g_btnlower, g_btnarg);
    }

  return OK;
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: btn_lower_initialize
 *
 * Description:
 *   Initialize the generic button lower half driver, bind it and register
 *   it with the upper half button driver as devname.
 *
 ****************************************************************************/

int btn_lower_initialize(FAR const char *devname)
{
  g_btnnum = board_button_initialize();
  return btn_register(devname, &g_btnlower);
}

#endif /* CONFIG_INPUT_BUTTONS_LOWER */