diff --git a/sys/modules/ppbus/Makefile b/sys/modules/ppbus/Makefile
index fc0162a65c56..fb28f7ab22c3 100644
--- a/sys/modules/ppbus/Makefile
+++ b/sys/modules/ppbus/Makefile
@@ -3,7 +3,7 @@
 
 .PATH:	${.CURDIR}/../../dev/ppbus
 KMOD=	ppbus
-SRCS=	bus_if.h device_if.h ppbus_if.h \
+SRCS=	bus_if.h device_if.h ppbus_if.h ppbus_if.c \
 	opt_ppb_1284.h opt_ppbus.h \
 	ppb_1284.c ppb_base.c ppb_msq.c ppbconf.c