--- zzzz-none-000/linux-4.1.38/drivers/isdn/hardware/avm/Kconfig	2017-01-18 18:48:06.000000000 +0000
+++ bcm63-7582-715/linux-4.1.38/drivers/isdn/hardware/avm/Kconfig	2020-11-25 10:06:48.000000000 +0000
@@ -61,4 +61,6 @@
 	  Enable support for the AVM C4/C2 PCI cards.
 	  These cards handle 4/2 BRI ISDN lines (8/4 channels).
 
+source "drivers/isdn/isdn_fon5/Kconfig"
+
 endif # CAPI_AVM