diff --git a/sound/soc/rockchip/rk3399_gru_sound.c b/sound/soc/rockchip/rk3399_gru_sound.c
index 9ed735a6cf49ac352d237850423a276ed926ffd4..0cbd23555ba4f752cf4cb2db07283e36e46db5ac 100644
--- a/sound/soc/rockchip/rk3399_gru_sound.c
+++ b/sound/soc/rockchip/rk3399_gru_sound.c
@@ -38,7 +38,7 @@
 
 #define SOUND_FS	256
 
-unsigned int rt5514_dmic_delay;
+static unsigned int rt5514_dmic_delay;
 
 static struct snd_soc_jack rockchip_sound_jack;