--- zzzz-none-000/linux-3.10.107/drivers/rtc/Kconfig	2017-06-27 09:49:32.000000000 +0000
+++ vr9-7490-729/linux-3.10.107/drivers/rtc/Kconfig	2021-11-10 11:53:55.000000000 +0000
@@ -1247,6 +1247,11 @@
 
 	  If this driver is compiled as a module, it will be named
 	  rtc-hid-sensor-time.
-
+config RTC_DRV_AVM_REF_CLOCK
+    tristate "RTC Driver for external Clock source (DECT)"
+    depends on RTC_CLASS || AVM_DECT || ISDN_CAPI
+    default n
+    help
+        Clock source for Calibrate RTC device driver
 
 endif # RTC_CLASS