move backlight variable declarations from header to c file

app/backlight.c

@@ -6,9 +6,16 @@
 
 #define BACKLIGHT_IDLE_POLLING_RATE_MS 500
 
+static struct {
+	uint64_t last_triggered;
+	bool idling;
+	bool alarm_is_set;
+	uint8_t backlight_level;
+} self;
+
 void backlight_sync(void)
 {
-	pwm_set_gpio_level(PIN_BKL, backlight_level  * 0x80);
+	pwm_set_gpio_level(PIN_BKL, self.backlight_level  * 0x80);
 }
 
 static int64_t idle_detector_timer_task(alarm_id_t id, void *user_data)
@@ -18,50 +25,50 @@ static int64_t idle_detector_timer_task(alarm_id_t id, void *user_data)
 
 	uint8_t current_dimming_delay = reg_get_value(REG_ID_BK3);
 	if (current_dimming_delay == 0) {
-		idling = true;
+		self.idling = true;
 		cancel_alarm(id);
-		alarm_is_set = false;
-	} else if (!idling && to_ms_since_boot(get_absolute_time()) - last_triggered > (current_dimming_delay * 500)) {
-		idling = true;
+		self.alarm_is_set = false;
+	} else if (!self.idling && to_ms_since_boot(get_absolute_time()) - self.last_triggered > (current_dimming_delay * 500)) {
+		self.idling = true;
 		cancel_alarm(id);
-		alarm_is_set = false;
-		backlight_level = reg_get_value(REG_ID_BK4);
+		self.alarm_is_set = false;
+		self.backlight_level = reg_get_value(REG_ID_BK4);
 		backlight_sync();
 	}
 	return BACKLIGHT_IDLE_POLLING_RATE_MS * 1000;
 }
 
 void backlight_trigger(void)
 {
-	idling = false;
-	last_triggered = to_ms_since_boot(get_absolute_time());
+	self.idling = false;
+	self.last_triggered = to_ms_since_boot(get_absolute_time());
 	uint8_t desired_brightness = reg_get_value(REG_ID_BKL);
-	if (backlight_level < desired_brightness) {
-		backlight_level = desired_brightness;
+	if (self.backlight_level < desired_brightness) {
+		self.backlight_level = desired_brightness;
 		backlight_sync();
 	}
-	if (!alarm_is_set) {
+	if (!self.alarm_is_set) {
 		add_alarm_in_ms(BACKLIGHT_IDLE_POLLING_RATE_MS, idle_detector_timer_task, NULL, true);
-		alarm_is_set = true;
+		self.alarm_is_set = true;
 	}
 }
 
 void backlight_init(void)
 {
-	idling = false;
+	self.idling = false;
 	gpio_set_function(PIN_BKL, GPIO_FUNC_PWM);
 
 	const uint slice_num = pwm_gpio_to_slice_num(PIN_BKL);
 
 	pwm_config config = pwm_get_default_config();
 	pwm_init(slice_num, &config, true);
 
- 	backlight_level = reg_get_value(REG_ID_BKL);
+ 	self.backlight_level = reg_get_value(REG_ID_BKL);
 	backlight_sync();
-	last_triggered = 0;
+	self.last_triggered = 0;
 
 	if (reg_get_value(REG_ID_BK3) > 0) {
 		add_alarm_in_ms(BACKLIGHT_IDLE_POLLING_RATE_MS, idle_detector_timer_task, NULL, true);
-		alarm_is_set = true;
+		self.alarm_is_set = true;
 	}
 }

app/backlight.h

@@ -3,11 +3,6 @@
 #include <stdint.h>
 #include <stdbool.h>
 
-uint64_t last_triggered;
-bool idling;
-bool alarm_is_set;
-uint8_t backlight_level;
-
 void backlight_trigger(void);
 void backlight_sync(void);
 void backlight_init(void);