leds: backlight trigger: Move blank-state handling into helper

Move the handling of blank-state updates into a separate helper,
so that is can be called without the fbdev event. No functional
changes.

v2:
- rename helper to avoid renaming in a later patch (Lee)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Simona Vetter <simona.vetter@ffwll.ch>
Link: https://lore.kernel.org/r/20250321095517.313713-10-tzimmermann@suse.de
Signed-off-by: Lee Jones <lee@kernel.org>

Author: Thomas Zimmermann

drivers/leds/trigger/ledtrig-backlight.c

@@ -25,12 +25,28 @@ struct bl_trig_notifier {
 	unsigned invert;
 };
 
+static void ledtrig_backlight_notify_blank(struct bl_trig_notifier *n, int new_status)
+{
+	struct led_classdev *led = n->led;
+
+	if (new_status == n->old_status)
+		return;
+
+	if ((n->old_status == UNBLANK) ^ n->invert) {
+		n->brightness = led->brightness;
+		led_set_brightness_nosleep(led, LED_OFF);
+	} else {
+		led_set_brightness_nosleep(led, n->brightness);
+	}
+
+	n->old_status = new_status;
+}
+
 static int fb_notifier_callback(struct notifier_block *p,
 				unsigned long event, void *data)
 {
 	struct bl_trig_notifier *n = container_of(p,
 					struct bl_trig_notifier, notifier);
-	struct led_classdev *led = n->led;
 	struct fb_event *fb_event = data;
 	int *blank;
 	int new_status;
@@ -42,17 +58,7 @@ static int fb_notifier_callback(struct notifier_block *p,
 	blank = fb_event->data;
 	new_status = *blank ? BLANK : UNBLANK;
 
-	if (new_status == n->old_status)
-		return 0;
-
-	if ((n->old_status == UNBLANK) ^ n->invert) {
-		n->brightness = led->brightness;
-		led_set_brightness_nosleep(led, LED_OFF);
-	} else {
-		led_set_brightness_nosleep(led, n->brightness);
-	}
-
-	n->old_status = new_status;
+	ledtrig_backlight_notify_blank(n, new_status);
 
 	return 0;
 }