diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
index e44c7577da5b..f2a98acddda3 100644
--- a/arch/arm/mach-bcm283x/include/mach/mbox.h
+++ b/arch/arm/mach-bcm283x/include/mach/mbox.h
@@ -230,6 +230,7 @@ struct bcm2835_mbox_tag_set_power_state {
 #define BCM2835_MBOX_CLOCK_ID_SDRAM	8
 #define BCM2835_MBOX_CLOCK_ID_PIXEL	9
 #define BCM2835_MBOX_CLOCK_ID_PWM	10
+#define BCM2835_MBOX_CLOCK_ID_EMMC2	12
 
 struct bcm2835_mbox_tag_get_clock_rate {
 	struct bcm2835_mbox_tag_hdr tag_hdr;