HID: handle all multitouch devices through hid-multitouch

When the quirk HID_QUIRK_MULTITOUCH is present and when hid-multitouch
is loaded, let's pass the device to hid-multitouch even if it has
not been registered in hid-multitouch.

If any other driver wants to take precedence over hid-multitouch,
the usual way of adding it to hid_have_special_driver will work as
the quirk HID_QUIRK_MULTITOUCH won't be set by the generic hid layer.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@enac.fr>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 4f4143c..05a0c9a 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1232,7 +1232,6 @@
 		hdev->claimed |= HID_CLAIMED_INPUT;
 	if (hdev->quirks & HID_QUIRK_MULTITOUCH) {
 		/* this device should be handled by hid-multitouch, skip it */
-		hdev->quirks &= ~HID_QUIRK_MULTITOUCH;
 		return -ENODEV;
 	}
 
@@ -1667,6 +1666,10 @@
 	struct hid_driver *hdrv = container_of(drv, struct hid_driver, driver);
 	struct hid_device *hdev = container_of(dev, struct hid_device, dev);
 
+	if ((hdev->quirks & HID_QUIRK_MULTITOUCH) &&
+		!strncmp(hdrv->name, "hid-multitouch", 14))
+		return 1;
+
 	if (!hid_match_device(hdev, hdrv))
 		return 0;
 
@@ -1691,8 +1694,11 @@
 	if (!hdev->driver) {
 		id = hid_match_device(hdev, hdrv);
 		if (id == NULL) {
-			ret = -ENODEV;
-			goto unlock;
+			if (!((hdev->quirks & HID_QUIRK_MULTITOUCH) &&
+				!strncmp(hdrv->name, "hid-multitouch", 14))) {
+				ret = -ENODEV;
+				goto unlock;
+			}
 		}
 
 		hdev->driver = hdrv;