mfd: rn5t618: Add RTC related registers

Defines for some RTC related registers were missing, also
they were not included in the volatile register list
Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/rn5t618.c

@@ -34,6 +34,8 @@ static bool rn5t618_volatile_reg(struct device *dev, unsigned int reg)
 	case RN5T618_IR_GPF:
 	case RN5T618_MON_IOIN:
 	case RN5T618_INTMON:
+	case RN5T618_RTC_CTRL1 ... RN5T618_RTC_CTRL2:
+	case RN5T618_RTC_SECONDS ... RN5T618_RTC_YEAR:
 		return true;
 	default:
 		return false;

include/linux/mfd/rn5t618.h

@@ -139,6 +139,17 @@
 #define RN5T618_INTPOL			0x9c
 #define RN5T618_INTEN			0x9d
 #define RN5T618_INTMON			0x9e
+
+#define RN5T618_RTC_SECONDS     0xA0
+#define RN5T618_RTC_MDAY        0xA4
+#define RN5T618_RTC_MONTH       0xA5
+#define RN5T618_RTC_YEAR        0xA6
+#define RN5T618_RTC_ADJUST      0xA7
+#define RN5T618_RTC_ALARM_Y_SEC 0xA8
+#define RN5T618_RTC_DAL_MONTH   0xAC
+#define RN5T618_RTC_CTRL1       0xAE
+#define RN5T618_RTC_CTRL2       0xAF
+
 #define RN5T618_PREVINDAC		0xb0
 #define RN5T618_BATDAC			0xb1
 #define RN5T618_CHGCTL1			0xb3