diff --git a/sound/soc/codecs/cs42l51.h b/sound/soc/codecs/cs42l51.h
index 641ef18..8c55bf3 100644
--- a/sound/soc/codecs/cs42l51.h
+++ b/sound/soc/codecs/cs42l51.h
@@ -26,6 +26,7 @@
 #define CS42L51_CHIP_ID			0x1B
 #define CS42L51_CHIP_REV_A		0x00
 #define CS42L51_CHIP_REV_B		0x01
+#define CS42L51_CHIP_REV_MASK		0x07
 
 #define CS42L51_CHIP_REV_ID		0x01
 #define CS42L51_MK_CHIP_REV(a, b)	((a)<<3|(b))