usb: misc: uss720: check for incompatible versions of the Belkin F5U002

The incompatible device in my possession has a sticker that says
"F5U002 Rev 2" and "P80453-B", and lsusb identifies it as
"050d:0002 Belkin Components IEEE-1284 Controller". There is a bug
report from 2007 from Michael Trausch who was seeing the exact same
errors that I saw in 2024 trying to use this cable.

Link: https://lore.kernel.org/all/46DE5830.9060401@trausch.us/
Signed-off-by: Alex Henrie <alexhenrie24@gmail.com>
Link: https://lore.kernel.org/r/20240326150723.99939-5-alexhenrie24@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c
index 5423da08a46765928e9dce99dfbdc3e132f16515..b26c1d382d5990bd7a975c3981f6b2c410a2005a 100644 (file)
--- a/drivers/usb/misc/uss720.c
+++ b/drivers/usb/misc/uss720.c
@@ -677,7 +677,7 @@ static int uss720_probe(struct usb_interface *intf,
        struct parport_uss720_private *priv;
        struct parport *pp;
        unsigned char reg;
-       int i;
+       int ret;
 
        dev_dbg(&intf->dev, "probe: vendor id 0x%x, device id 0x%x\n",
                le16_to_cpu(usbdev->descriptor.idVendor),
@@ -688,8 +688,8 @@ static int uss720_probe(struct usb_interface *intf,
                usb_put_dev(usbdev);
                return -ENODEV;
        }
-       i = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
-       dev_dbg(&intf->dev, "set interface result %d\n", i);
+       ret = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
+       dev_dbg(&intf->dev, "set interface result %d\n", ret);
 
        interface = intf->cur_altsetting;
 
@@ -728,12 +728,18 @@ static int uss720_probe(struct usb_interface *intf,
        set_1284_register(pp, 7, 0x00, GFP_KERNEL);
        set_1284_register(pp, 6, 0x30, GFP_KERNEL);  /* PS/2 mode */
        set_1284_register(pp, 2, 0x0c, GFP_KERNEL);
-       /* debugging */
-       get_1284_register(pp, 0, &reg, GFP_KERNEL);
+
+       /* The Belkin F5U002 Rev 2 P80453-B USB parallel port adapter shares the
+        * device ID 050d:0002 with some other device that works with this
+        * driver, but it itself does not. Detect and handle the bad cable
+        * here. */
+       ret = get_1284_register(pp, 0, &reg, GFP_KERNEL);
        dev_dbg(&intf->dev, "reg: %7ph\n", priv->reg);
+       if (ret < 0)
+               return ret;
 
-       i = usb_find_last_int_in_endpoint(interface, &epd);
-       if (!i) {
+       ret = usb_find_last_int_in_endpoint(interface, &epd);
+       if (!ret) {
                dev_dbg(&intf->dev, "epaddr %d interval %d\n",
                                epd->bEndpointAddress, epd->bInterval);
        }