diff --git a/sys/modules/tpm/Makefile b/sys/modules/tpm/Makefile
index 652e9c896ba7..fdfc016ea315 100644
--- a/sys/modules/tpm/Makefile
+++ b/sys/modules/tpm/Makefile
@@ -3,7 +3,9 @@
 .PATH:	${.CURDIR}/../../dev/tpm
 
 KMOD=	tpm
-SRCS=	tpm.c tpm_isa.c tpm_acpi.c isa_if.h opt_acpi.h acpi_if.h \
-	bus_if.h device_if.h
+
+SRCS=	tpm.c bus_if.h device_if.h
+#Bus specific stuff.
+SRCS+=	tpm_isa.c tpm_acpi.c isa_if.h opt_acpi.h acpi_if.h
 
 .include <bsd.kmod.mk>