USB: ftdi_sio: Workaround for broken Matrix Orbital serial port

Workaround for the FT232RL-based, Matrix Orbital VK204-25-USB serial port
added to the ftdi_sio driver.

The device has an invalid endpoint descriptor, which must be modified
before it can be used.

Signed-off-by: Kevin Vance <[e-mail]>
Cc: stable <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/serial/ftdi_sio.c

···
 };
 
 static int   ftdi_jtag_probe		(struct usb_serial *serial);
+static int   ftdi_mtxorb_hack_setup	(struct usb_serial *serial);
 static void  ftdi_USB_UIRT_setup	(struct ftdi_private *priv);
 static void  ftdi_HE_TIRA1_setup	(struct ftdi_private *priv);
 
 static struct ftdi_sio_quirk ftdi_jtag_quirk = {
 	.probe	= ftdi_jtag_probe,
+};
+
+static struct ftdi_sio_quirk ftdi_mtxorb_hack_quirk = {
+	.probe  = ftdi_mtxorb_hack_setup,
 };
 
 static struct ftdi_sio_quirk ftdi_USB_UIRT_quirk = {
···
 	{ USB_DEVICE(FTDI_VID, FTDI_MTXORB_4_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_MTXORB_5_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_MTXORB_6_PID) },
+	{ USB_DEVICE(MTXORB_VK_VID, MTXORB_VK_PID),
+		.driver_info = (kernel_ulong_t)&ftdi_mtxorb_hack_quirk },
 	{ USB_DEVICE(FTDI_VID, FTDI_PERLE_ULTRAPORT_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_PIEGROUP_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_TNC_X_PID) },
···
 	if (interface == udev->actconfig->interface[0]) {
 		info("Ignoring serial port reserved for JTAG");
 		return -ENODEV;
+	}
+
+	return 0;
+}
+
+/*
+ * The Matrix Orbital VK204-25-USB has an invalid IN endpoint.
+ * We have to correct it if we want to read from it.
+ */
+static int ftdi_mtxorb_hack_setup(struct usb_serial *serial)
+{
+	struct usb_host_endpoint *ep = serial->dev->ep_in[1];
+	struct usb_endpoint_descriptor *ep_desc = &ep->desc;
+
+	if (ep->enabled && ep_desc->wMaxPacketSize == 0) {
+		ep_desc->wMaxPacketSize = 0x40;
+		info("Fixing invalid wMaxPacketSize on read pipe");
 	}
 
 	return 0;

drivers/usb/serial/ftdi_sio.h

···
  * (http://www.joernonline.de/dw/doku.php?id=start&idx=projects:oocdlink) */
 #define FTDI_OOCDLINK_PID	0xbaf8	/* Amontec JTAGkey */
 
+/*
+ * The following are the values for the Matrix Orbital VK204-25-USB
+ * display, which use the FT232RL.
+ */
+#define MTXORB_VK_VID		0x1b3d
+#define MTXORB_VK_PID		0x0158
+
 /* Interbiometrics USB I/O Board */
 /* Developed for Interbiometrics by Rudolf Gugler */
 #define INTERBIOMETRICS_VID              0x1209