USB: qcserial: make probe more flexible

Preparing qcprobe support for more than just strict
Gobi 1k or 2k+ devices.  Many newer Qualcomm based
devices provide the same serial ports, but using
varying USB interface layouts.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 7556f34..a9c4dc4 100644 (file)
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -143,14 +143,13 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
 
        spin_lock_init(&data->susp_lock);
 
-       switch (nintf) {
-       case 1:
+       if (nintf == 1) {
                /* QDL mode */
                /* Gobi 2000 has a single altsetting, older ones have two */
                if (serial->interface->num_altsetting == 2)
                        intf = &serial->interface->altsetting[1];
                else if (serial->interface->num_altsetting > 2)
-                       break;
+                       goto done;
 
                if (intf->desc.bNumEndpoints == 2 &&
                    usb_endpoint_is_bulk_in(&intf->endpoint[0].desc) &&
@@ -162,10 +161,18 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
                        else
                                altsetting = 1;
                }
-               break;
+               goto done;
 
-       case 3:
-       case 4:
+       }
+
+       if (nintf < 3 || nintf > 4) {
+               dev_err(dev, "unknown number of interfaces: %d\n", nintf);
+               goto done;
+       }
+
+       /* default to enabling interface */
+       altsetting = 0;
+       switch (ifnum) {
                /* Composite mode; don't bind to the QMI/net interface as that
                 * gets handled by other drivers.
                 */
@@ -183,27 +190,28 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
                 * 3: NMEA
                 */
 
-               if (ifnum == 1 && !is_gobi1k) {
+       case 1:
+               if (is_gobi1k)
+                       altsetting = -1;
+               else
                        dev_dbg(dev, "Gobi 2K+ DM/DIAG interface found\n");
-                       altsetting = 0;
-               } else if (ifnum == 2) {
-                       dev_dbg(dev, "Modem port found\n");
-                       altsetting = 0;
-               } else if (ifnum==3 && !is_gobi1k) {
+               break;
+       case 2:
+               dev_dbg(dev, "Modem port found\n");
+               break;
+       case 3:
+               if (is_gobi1k)
+                       altsetting = -1;
+               else
                        /*
                         * NMEA (serial line 9600 8N1)
                         * # echo "\$GPS_START" > /dev/ttyUSBx
                         * # echo "\$GPS_STOP"  > /dev/ttyUSBx
                         */
                        dev_dbg(dev, "Gobi 2K+ NMEA GPS interface found\n");
-                       altsetting = 0;
-               }
-               break;
-
-       default:
-               dev_err(dev, "unknown number of interfaces: %d\n", nintf);
        }
 
+done:
        if (altsetting >= 0) {
                retval = usb_set_interface(serial->dev, ifnum, altsetting);
                if (retval < 0) {