diff --git a/drivers/macintosh/via-pmu-backlight.c b/drivers/macintosh/via-pmu-backlight.c
index 89ed51571b62..50ada02ae75d 100644
--- a/drivers/macintosh/via-pmu-backlight.c
+++ b/drivers/macintosh/via-pmu-backlight.c
@@ -137,7 +137,7 @@ void pmu_backlight_set_sleep(int sleep)
 }
 #endif /* CONFIG_PM */
 
-void __init pmu_backlight_init()
+void __init pmu_backlight_init(void)
 {
 	struct backlight_properties props;
 	struct backlight_device *bd;