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>

2 files changed, 16 insertions, 7 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 4f4143cc789b..05a0c9a35bf2 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1232,7 +1232,6 @@ int hid_connect(struct hid_device *hdev, unsigned int connect_mask)
                 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 @@ static int hid_bus_match(struct device *dev, struct device_driver *drv)
         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 @@ static int hid_device_probe(struct device *dev)
         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;
diff --git a/drivers/hid/hid-multitouch.c b/drivers/hid/hid-multitouch.c
index 2088ab4e5db5..a61ba42e1bff 100644
--- a/drivers/hid/hid-multitouch.c
+++ b/drivers/hid/hid-multitouch.c
@@ -637,10 +637,12 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
         struct mt_device *td;
         struct mt_class *mtclass = mt_classes; /* MT_CLS_DEFAULT */
 
-        for (i = 0; mt_classes[i].name ; i++) {
-                if (id->driver_data == mt_classes[i].name) {
-                        mtclass = &(mt_classes[i]);
-                        break;
+        if (id) {
+                for (i = 0; mt_classes[i].name ; i++) {
+                        if (id->driver_data == mt_classes[i].name) {
+                                mtclass = &(mt_classes[i]);
+                                break;
+                        }
                 }
         }
 
@@ -648,6 +650,7 @@ static int mt_probe(struct hid_device *hdev, const struct hid_device_id *id)
          * that emit events over several HID messages.
          */
         hdev->quirks |= HID_QUIRK_NO_INPUT_SYNC;
+        hdev->quirks &= ~HID_QUIRK_MULTITOUCH;
 
         td = kzalloc(sizeof(struct mt_device), GFP_KERNEL);
         if (!td) {