USB: qcserial: Enable Diagnostics Monitor and GPS ports on Gobi 2000

this patch to qcserial.c enables the Diagnostics Monitor
and NMEA GPS ports on Qualcomm Gobi 2000 devices.

A Gobi 2000 device will provide 3 serial ports:
        # /dev/ttyUSB0 -> Diagnostics
        # /dev/ttyUSB1 -> 3G Modem
        # /dev/ttyUSB2 -> NMEA GPS port

* The Diagnostics Monitor uses Qualcomm's DM protocol; I used
  libqcdm (ModemManager) to talk to it, found it working, but at
  least DM commands 12 and 64 are not implemented on my device
  (Gobi 2000 built into Thinkpad x100e).

* Functionality of the 3G Modem port remains unchanged.

* The GPS port and how to enable it has been confirmed now in the
  Gobi 3000 source code at:
	https://www.codeaurora.org/patches/quic/gobi/
  Enable/disable GPS via:
        echo "\$GPS_START" > /dev/ttyUSB2
        # use GPS
        echo "\$GPS_STOP"  > /dev/ttyUSB2


Signed-off-by: Matthias G. Eckermann <mge@arcor.de>

1 files changed, 30 insertions, 1 deletions

diff --git a/drivers/usb/serial/qcserial.c b/drivers/usb/serial/qcserial.c
index 2846ad8883ae..8858201eb1d3 100644
--- a/drivers/usb/serial/qcserial.c
+++ b/drivers/usb/serial/qcserial.c
@@ -152,7 +152,22 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
         case 3:
         case 4:
                 /* Composite mode */
-                if (ifnum == 2) {
+                /* ifnum == 0 is a broadband network adapter */
+                if (ifnum == 1) {
+                        /*
+                         * Diagnostics Monitor (serial line 9600 8N1)
+                         * Qualcomm DM protocol
+                         * use "libqcdm" (ModemManager) for communication
+                         */
+                        dbg("Diagnostics Monitor found");
+                        retval = usb_set_interface(serial->dev, ifnum, 0);
+                        if (retval < 0) {
+                                dev_err(&serial->dev->dev,
+                                        "Could not set interface, error %d\n",
+                                        retval);
+                                retval = -ENODEV;
+                        }
+                } else if (ifnum == 2) {
                         dbg("Modem port found");
                         retval = usb_set_interface(serial->dev, ifnum, 0);
                         if (retval < 0) {
@@ -163,6 +178,20 @@ static int qcprobe(struct usb_serial *serial, const struct usb_device_id *id)
                                 kfree(data);
                         }
                         return retval;
+                } else if (ifnum==3) {
+                        /*
+                         * NMEA (serial line 9600 8N1)
+                         * # echo "\$GPS_START" > /dev/ttyUSBx
+                         * # echo "\$GPS_STOP"  > /dev/ttyUSBx
+                         */
+                        dbg("NMEA GPS interface found");
+                        retval = usb_set_interface(serial->dev, ifnum, 0);
+                        if (retval < 0) {
+                                dev_err(&serial->dev->dev,
+                                        "Could not set interface, error %d\n",
+                                        retval);
+                                retval = -ENODEV;
+                        }
                 }
                 break;