drm/bridge: parade-ps8622: Use backlight helper

backlight_properties.fb_blank is deprecated. The states it represents
are handled by other properties; but instead of accessing those
properties directly, drivers should use the helpers provided by
backlight.h.

Instead of retrieving the backlight brightness in struct
backlight_properties manually, and then checking whether the backlight
should be on at all, use backlight_get_brightness() which does all
this and insulates this from future changes.

Signed-off-by: Stephen Kitt <[email protected]>
Cc: Andrzej Hajda <[email protected]>
Cc: Neil Armstrong <[email protected]>
Cc: Robert Foss <[email protected]>
Cc: Laurent Pinchart <[email protected]>
Cc: Jonas Karlman <[email protected]>
Cc: Jernej Skrabec <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: [email protected]
Signed-off-by: Sam Ravnborg <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]

drivers/gpu/drm/bridge/parade-ps8622.c

@@ -324,11 +324,7 @@ static int ps8622_send_config(struct ps8622_bridge *ps8622)
 static int ps8622_backlight_update(struct backlight_device *bl)
 {
 	struct ps8622_bridge *ps8622 = dev_get_drvdata(&bl->dev);
-	int ret, brightness = bl->props.brightness;
-
-	if (bl->props.power != FB_BLANK_UNBLANK ||
-	    bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK))
-		brightness = 0;
+	int ret, brightness = backlight_get_brightness(bl);
 
 	if (!ps8622->enabled)
 		return -EINVAL;