USB: Ignore storage device in modem mode on DWN-652

D-Link DWN-652 in Modem mode exposes 3 interfaces
- First one is the USB storage one
- Second one is for both control and connection
- Third one is unknown

This patch avoids usb-storage trying to switch again when already in
modem mode, and exposes only 2 ttyUSB instead of 3 by not attaching
to the storage interface

Signed-off-by: Pascal Terjan <pterjan@mandriva.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/serial/option.c

@@ -43,6 +43,8 @@
 #include <linux/usb/serial.h>
 
 /* Function prototypes */
+static int  option_probe(struct usb_serial *serial,
+			const struct usb_device_id *id);
 static int  option_open(struct tty_struct *tty, struct usb_serial_port *port,
 							struct file *filp);
 static void option_close(struct usb_serial_port *port);
@@ -555,6 +557,7 @@ static struct usb_serial_driver option_1port_device = {
 	.usb_driver        = &option_driver,
 	.id_table          = option_ids,
 	.num_ports         = 1,
+	.probe             = option_probe,
 	.open              = option_open,
 	.close             = option_close,
 	.dtr_rts	   = option_dtr_rts,
@@ -631,6 +634,18 @@ static void __exit option_exit(void)
 module_init(option_init);
 module_exit(option_exit);
 
+static int option_probe(struct usb_serial *serial,
+			const struct usb_device_id *id)
+{
+	/* D-Link DWM 652 still exposes CD-Rom emulation interface in modem mode */
+	if (serial->dev->descriptor.idVendor == DLINK_VENDOR_ID &&
+		serial->dev->descriptor.idProduct == DLINK_PRODUCT_DWM_652 &&
+		serial->interface->cur_altsetting->desc.bInterfaceClass == 0x8)
+		return -ENODEV;
+
+	return 0;
+}
+
 static void option_set_termios(struct tty_struct *tty,
 		struct usb_serial_port *port, struct ktermios *old_termios)
 {