HID: hid-multitouch: Filter collections by application usage.

This change fixes two problems.

First, it ensures that the hid-multitouch driver does not incorrectly
map GenericDesktop usages that are intended for other applications,
such as a Mouse.

Second, it sets the appropriate input properties so that user-space
can distinguish TouchScreen devices (INPUT_PROP_DIRECT) from
TouchPad devices (INPUT_PROP_POINTER) and configure them accordingly.

Signed-off-by: jeffbrown@android.com
Acked-By: Benjamin Tissoires <Benjamin_Tissoires@logitech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-multitouch.c

@@ -213,6 +213,16 @@ static int mt_input_mapping(struct hid_device *hdev, struct hid_input *hi,
 	struct mt_class *cls = td->mtclass;
 	__s32 quirks = cls->quirks;
 
+	/* Only map fields from TouchScreen or TouchPad collections.
+         * We need to ignore fields that belong to other collections
+         * such as Mouse that might have the same GenericDesktop usages. */
+	if (field->application == HID_DG_TOUCHSCREEN)
+		set_bit(INPUT_PROP_DIRECT, hi->input->propbit);
+	else if (field->application == HID_DG_TOUCHPAD)
+		set_bit(INPUT_PROP_POINTER, hi->input->propbit);
+	else
+		return 0;
+
 	switch (usage->hid & HID_USAGE_PAGE) {
 
 	case HID_UP_GENDESK: