diff --git a/sound/soc/codecs/wm8904.c b/sound/soc/codecs/wm8904.c
index 4dfa8dc..c173ab3 100644
--- a/sound/soc/codecs/wm8904.c
+++ b/sound/soc/codecs/wm8904.c
@@ -658,7 +658,8 @@
 static int cp_event(struct snd_soc_dapm_widget *w,
 		    struct snd_kcontrol *kcontrol, int event)
 {
-	BUG_ON(event != SND_SOC_DAPM_POST_PMU);
+	if (WARN_ON(event != SND_SOC_DAPM_POST_PMU))
+		return -EINVAL;
 
 	/* Maximum startup time */
 	udelay(500);