diff --git a/drivers/mfd/sec-core.c b/drivers/mfd/sec-core.c
index 714e2135210e..306b3a282c29 100644
--- a/drivers/mfd/sec-core.c
+++ b/drivers/mfd/sec-core.c
@@ -141,6 +141,8 @@ static const struct regmap_config s5m8767_regmap_config = {
 static const struct regmap_config sec_rtc_regmap_config = {
 	.reg_bits = 8,
 	.val_bits = 8,
+
+	.max_register = SEC_RTC_REG_MAX,
 };
 
 #ifdef CONFIG_OF
diff --git a/include/linux/mfd/samsung/rtc.h b/include/linux/mfd/samsung/rtc.h
index 94b7cd6d8891..4627f59ebd84 100644
--- a/include/linux/mfd/samsung/rtc.h
+++ b/include/linux/mfd/samsung/rtc.h
@@ -43,6 +43,8 @@ enum sec_rtc_reg {
 	SEC_RTC_STATUS,
 	SEC_WTSR_SMPL_CNTL,
 	SEC_RTC_UDR_CON,
+
+	SEC_RTC_REG_MAX,
 };
 
 #define RTC_I2C_ADDR		(0x0C >> 1)