USB: Select better matching USB drivers when available

Now that USB device drivers can reuse code from the generic USB device
driver, we need to make sure that they get selected rather than the
generic driver. Add an id_table and match vfunc to the usb_device_driver
struct, which will get used to select a better matching driver at
->probe time.

This is a similar mechanism to that used in the HID drivers, with the
generic driver being selected unless there's a better matching one found
in the registered drivers (see hid_generic_match() in
drivers/hid/hid-generic.c).

Signed-off-by: Bastien Nocera <hadess@hadess.net>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20191016093933.693-5-hadess@hadess.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 697898327b44..9d1502a9571d 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -818,13 +818,24 @@ static int usb_device_match(struct device *dev, struct device_driver *drv)
 {
 	/* devices and interfaces are handled separately */
 	if (is_usb_device(dev)) {
+		struct usb_device *udev;
+		struct usb_device_driver *udrv;
 
 		/* interface drivers never match devices */
 		if (!is_usb_device_driver(drv))
 			return 0;
 
-		/* TODO: Add real matching code */
-		return 1;
+		udev = to_usb_device(dev);
+		udrv = to_usb_device_driver(drv);
+
+		if (udrv->id_table &&
+		    usb_device_match_id(udev, udrv->id_table) != NULL) {
+			return 1;
+		}
+
+		if (udrv->match)
+			return udrv->match(udev);
+		return 0;
 
 	} else if (is_usb_interface(dev)) {
 		struct usb_interface *intf;