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/*
* On/off-switch
*
* Copyright (c) 2014 Michael Buesch <m@bues.ch>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "onoffswitch.h"
#include "util.h"
#include "main.h"
#include <avr/io.h>
/* Port definitions for the hardware on/off-switch. */
#define ONOFFSWITCH_DDR DDRD
#define ONOFFSWITCH_PORT PORTD
#define ONOFFSWITCH_PIN PIND
#define ONOFFSWITCH_BIT PD3
/* Saved state. */
static enum onoff_state onoffswitch_state = ONOFF_IS_OFF;
/* Timestamp for the next check. */
static jiffies_t next_check;
static void onoffswitch_eliminate_edge_states(void)
{
if (onoffswitch_state == ONOFF_SWITCHED_ON)
onoffswitch_state = ONOFF_IS_ON;
else if (onoffswitch_state == ONOFF_SWITCHED_OFF)
onoffswitch_state = ONOFF_IS_OFF;
}
static void onoffswitch_update(void)
{
bool new_state, old_state;
/* Get the state. */
new_state = !!(ONOFFSWITCH_PIN & (1 << ONOFFSWITCH_BIT));
/* Switch logic is inverted. */
new_state = !new_state;
/* Detect state and edges. */
old_state = (onoffswitch_state != ONOFF_IS_OFF);
if (new_state && !old_state)
onoffswitch_state = ONOFF_SWITCHED_ON;
else if (!new_state && old_state)
onoffswitch_state = ONOFF_SWITCHED_OFF;
else if (new_state)
onoffswitch_state = ONOFF_IS_ON;
else
onoffswitch_state = ONOFF_IS_OFF;
}
/* Initialize the on/off-switch. */
void onoffswitch_init(void)
{
ONOFFSWITCH_DDR &= ~(1 << ONOFFSWITCH_BIT);
ONOFFSWITCH_PORT |= (1 << ONOFFSWITCH_BIT);
_delay_ms(20); /* Wait for pull-up. */
onoffswitch_update();
onoffswitch_eliminate_edge_states();
}
/* Periodic work. */
void onoffswitch_work(void)
{
jiffies_t now = jiffies_get();
onoffswitch_eliminate_edge_states();
if (!time_before(now, next_check)) {
next_check = now + msec_to_jiffies(100);
onoffswitch_update();
}
}
/* Get the on/off-switch state. */
enum onoff_state onoffswitch_get_state(void)
{
return onoffswitch_state;
}
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