[CAN]: Add PF_CAN core module

This patch adds the CAN core functionality but no protocols or drivers.
No protocol implementations are included here.  They come as separate
patches.  Protocol numbers are already in include/linux/can.h.

Signed-off-by: Oliver Hartkopp <oliver.hartkopp@volkswagen.de>
Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/can/Kconfig b/net/can/Kconfig
new file mode 100644
index 0000000..8b92790
--- /dev/null
+++ b/net/can/Kconfig
@@ -0,0 +1,17 @@
+#
+# Controller Area Network (CAN) network layer core configuration
+#
+
+menuconfig CAN
+	depends on NET
+	tristate "CAN bus subsystem support"
+	---help---
+	  Controller Area Network (CAN) is a slow (up to 1Mbit/s) serial
+	  communications protocol which was developed by Bosch in
+	  1991, mainly for automotive, but now widely used in marine
+	  (NMEA2000), industrial, and medical applications.
+	  More information on the CAN network protocol family PF_CAN
+	  is contained in <Documentation/networking/can.txt>.
+
+	  If you want CAN support you should say Y here and also to the
+	  specific driver for your controller(s) below.