Debounce button presses in software

kestrel/src/zephyr.c

@@ -32,6 +32,8 @@ static struct k_thread kestrel_service_thread_data;
 
 #define KESTREL_IDLE_THREAD_PRIORITY		K_PRIO_PREEMPT(CONFIG_NUM_PREEMPT_PRIORITIES - 1)
 
+#define BUTTON_PRESS_DEBOUNCE_DELAY_MS	200
+
 static void kestrel_init_thread(void)
 {
 	kestrel_init();
@@ -60,6 +62,8 @@ static void kestrel_service_thread(void)
 
 void host_power_button_pressed(const struct device *dev, struct gpio_callback *cb, uint32_t pins)
 {
+	static uint64_t last_press = 0;
+
 	int want_power_on = 0;
 	int want_power_off = 0;
 
@@ -78,16 +82,23 @@ void host_power_button_pressed(const struct device *dev, struct gpio_callback *c
 	// Re-activate interupts on exiting critical section
 	irq_unlock(key);
 
+	if ((k_uptime_get() - last_press) > BUTTON_PRESS_DEBOUNCE_DELAY_MS) {
+		// The debounce delay has passed since last press, handle request
 		if (want_power_on) {
 			power_on_host();
 		}
 		else if (want_power_off) {
 			power_off_chassis();
 		}
+	}
+
+	last_press = k_uptime_get();
 }
 
 void host_reset_button_pressed(const struct device *dev, struct gpio_callback *cb, uint32_t pins)
 {
+	static uint64_t last_press = 0;
+
 	// Deactivate interrupts on entering critical section
 	int key = irq_lock();
 
@@ -97,7 +108,12 @@ void host_reset_button_pressed(const struct device *dev, struct gpio_callback *c
 	// Re-activate interupts on exiting critical section
 	irq_unlock(key);
 
+	if ((k_uptime_get() - last_press) > BUTTON_PRESS_DEBOUNCE_DELAY_MS) {
+		// The debounce delay has passed since last press, handle request
 		LOG_WRN("[FIXME] Reset button pressed, but not implemented!");
+	}
+
+	last_press = k_uptime_get();
 }
 
 static int configure_gpios(void)