net/usb: Add Samsung Kalmia driver for Samsung GT-B3730

Introducing driver for the network port of Samsung Kalmia based USB LTE modems.
It has also an ACM interface that previous patches associates with the "option"
module. To access those interfaces, the modem must first be switched from modem
mode using a tool like usb_modeswitch.

As the proprietary protocol has been discovered by watching the MS Windows driver
behavior, there might be errors in the protocol handling, but stable and fast
connection has been established for hours with Norwegian operator NetCom that
distributes this modem with their LTE/4G subscription.

More and updated information about how to use this driver is available here:

http://www.draisberghof.de/usb_modeswitch/bb/viewtopic.php?t=465
https://github.com/mkotsbak/Samsung-GT-B3730-linux-driver

Signed-off-by: Marius B. Kotsbak <marius@kotsbak.com>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>

drivers/net/usb/Kconfig

@@ -385,6 +385,16 @@ config USB_NET_CX82310_ETH
 	  router with USB ethernet port. This driver is for routers only,
 	  it will not work with ADSL modems (use cxacru driver instead).
 
+config USB_NET_KALMIA
+	tristate "Samsung Kalmia based LTE USB modem"
+	depends on USB_USBNET
+	help
+	  Choose this option if you have a Samsung Kalmia based USB modem
+	  as Samsung GT-B3730.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called kalmia.
+
 config USB_HSO
 	tristate "Option USB High Speed Mobile Devices"
 	depends on USB && RFKILL

drivers/net/usb/Makefile

@@ -23,6 +23,7 @@ obj-$(CONFIG_USB_NET_MCS7830)	+= mcs7830.o
 obj-$(CONFIG_USB_USBNET)	+= usbnet.o
 obj-$(CONFIG_USB_NET_INT51X1)	+= int51x1.o
 obj-$(CONFIG_USB_CDC_PHONET)	+= cdc-phonet.o
+obj-$(CONFIG_USB_NET_KALMIA)	+= kalmia.o
 obj-$(CONFIG_USB_IPHETH)	+= ipheth.o
 obj-$(CONFIG_USB_SIERRA_NET)	+= sierra_net.o
 obj-$(CONFIG_USB_NET_CX82310_ETH)	+= cx82310_eth.o