can: add slcan driver for serial/USB-serial CAN adapters

This patch adds support for serial/USB-serial CAN adapters implementing the
LAWICEL ASCII protocol for CAN frame transport over serial lines.

The driver implements the SLCAN line discipline and is heavily based on the
slip.c driver. Therefore the code style remains similar to slip.c to be able
to apply changes of the SLIP driver to the SLCAN driver easily.

For more details see the slcan Kconfig entry.
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/can/Kconfig

@@ -12,6 +12,27 @@ config CAN_VCAN
 	  This driver can also be built as a module.  If so, the module
 	  will be called vcan.
 
+config CAN_SLCAN
+	tristate "Serial / USB serial CAN Adaptors (slcan)"
+	depends on CAN
+	default N
+	---help---
+	  CAN driver for several 'low cost' CAN interfaces that are attached
+	  via serial lines or via USB-to-serial adapters using the LAWICEL
+	  ASCII protocol. The driver implements the tty linediscipline N_SLCAN.
+
+	  As only the sending and receiving of CAN frames is implemented, this
+	  driver should work with the (serial/USB) CAN hardware from:
+	  www.canusb.com / www.can232.com / www.mictronic.com / www.canhack.de
+
+	  Userspace tools to attach the SLCAN line discipline (slcan_attach,
+	  slcand) can be found in the can-utils at the SocketCAN SVN, see
+	  http://developer.berlios.de/projects/socketcan for details.
+
+	  The slcan driver supports up to 10 CAN netdevices by default which
+	  can be changed by the 'maxdev=xx' module option. This driver can
+	  also be built as a module. If so, the module will be called slcan.
+
 config CAN_DEV
 	tristate "Platform CAN drivers with Netlink support"
 	depends on CAN

drivers/net/can/Makefile

@@ -3,6 +3,7 @@
 #
 
 obj-$(CONFIG_CAN_VCAN)		+= vcan.o
+obj-$(CONFIG_CAN_SLCAN)		+= slcan.o
 
 obj-$(CONFIG_CAN_DEV)		+= can-dev.o
 can-dev-y			:= dev.o