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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Button module for Chrome EC */
#include "button.h"
#include "common.h"
#include "console.h"
#include "gpio.h"
#include "hooks.h"
#include "keyboard_protocol.h"
#include "timer.h"
#include "util.h"
/* Console output macro */
#define CPRINTS(format, args...) cprints(CC_SWITCH, format, ## args)
struct button_state_t {
uint64_t debounce_time;
int debounced_pressed;
};
static struct button_state_t state[CONFIG_BUTTON_COUNT];
static uint64_t next_deferred_time;
/*
* Whether a button is currently pressed.
*/
static int raw_button_pressed(const struct button_config *button)
{
int raw_value = gpio_get_level(button->gpio);
return button->flags & BUTTON_FLAG_ACTIVE_HIGH ?
raw_value : !raw_value;
}
/*
* Button initialization.
*/
static void button_init(void)
{
int i;
CPRINTS("(re)initializing buttons and interrupts");
next_deferred_time = 0;
for (i = 0; i < CONFIG_BUTTON_COUNT; i++) {
state[i].debounced_pressed = raw_button_pressed(&buttons[i]);
state[i].debounce_time = 0;
gpio_enable_interrupt(buttons[i].gpio);
}
}
DECLARE_HOOK(HOOK_INIT, button_init, HOOK_PRIO_DEFAULT);
/*
* Handle debounced button changing state.
*/
static void button_change_deferred(void)
{
int i;
int new_pressed;
uint64_t soonest_debounce_time = 0;
uint64_t time_now = get_time().val;
for (i = 0; i < CONFIG_BUTTON_COUNT; i++) {
/* Skip this button if we are not waiting to debounce */
if (state[i].debounce_time == 0)
continue;
if (state[i].debounce_time <= time_now) {
/* Check if the state has changed */
new_pressed = raw_button_pressed(&buttons[i]);
if (state[i].debounced_pressed != new_pressed) {
state[i].debounced_pressed = new_pressed;
CPRINTS("Button '%s' was %s",
buttons[i].name, new_pressed ?
"pressed" : "released");
#ifdef HAS_TASK_KEYPROTO
keyboard_update_button(buttons[i].type,
new_pressed);
#endif
}
/* Clear the debounce time to stop checking it */
state[i].debounce_time = 0;
} else {
/*
* Make sure the next deferred call happens on or before
* each button needs it.
*/
soonest_debounce_time = (soonest_debounce_time == 0) ?
state[i].debounce_time :
MIN(soonest_debounce_time,
state[i].debounce_time);
}
}
if (soonest_debounce_time != 0) {
next_deferred_time = soonest_debounce_time;
hook_call_deferred(button_change_deferred,
next_deferred_time - time_now);
}
}
DECLARE_DEFERRED(button_change_deferred);
/*
* Handle a button interrupt.
*/
void button_interrupt(enum gpio_signal signal)
{
int i;
uint64_t time_now = get_time().val;
for (i = 0; i < CONFIG_BUTTON_COUNT; i++) {
if (buttons[i].gpio != signal)
continue;
state[i].debounce_time = time_now + buttons[i].debounce_us;
if (next_deferred_time <= time_now ||
next_deferred_time > state[i].debounce_time) {
next_deferred_time = state[i].debounce_time;
hook_call_deferred(button_change_deferred,
next_deferred_time - time_now);
}
break;
}
}
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