usb: cdc-wdm: Add device-id for Huawei 3G/LTE modems

[v2: Editorial changes suggested by Sergei Shtylyov]

These modems use the Qualcomm MSM Interface (QMI) protocol for
management of their CDC ECM like wwan interface.  This driver
is perfect for exporting the protocol to userspace.

The created character device will be indistinguishable from a
common AT command based Device Management interface, so
userspace applications must do some intelligent matching
on the USB device.

Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/class/cdc-wdm.c

@@ -31,13 +31,29 @@
 #define DRIVER_AUTHOR "Oliver Neukum"
 #define DRIVER_DESC "USB Abstract Control Model driver for USB WCM Device Management"
 
+#define HUAWEI_VENDOR_ID	0x12D1
+
 static const struct usb_device_id wdm_ids[] = {
 	{
 		.match_flags = USB_DEVICE_ID_MATCH_INT_CLASS |
 				 USB_DEVICE_ID_MATCH_INT_SUBCLASS,
 		.bInterfaceClass = USB_CLASS_COMM,
 		.bInterfaceSubClass = USB_CDC_SUBCLASS_DMM
 	},
+	{
+		/* 
+		 * Huawei E392, E398 and possibly other Qualcomm based modems
+		 * embed the Qualcomm QMI protocol inside CDC on CDC ECM like
+		 * control interfaces.  Userspace access to this is required
+		 * to configure the accompanying data interface
+		 */
+		.match_flags        = USB_DEVICE_ID_MATCH_VENDOR |
+					USB_DEVICE_ID_MATCH_INT_INFO,
+		.idVendor           = HUAWEI_VENDOR_ID,
+		.bInterfaceClass    = USB_CLASS_VENDOR_SPEC,
+		.bInterfaceSubClass = 1,
+		.bInterfaceProtocol = 9, /* NOTE: CDC ECM control interface! */
+	},
 	{ }
 };