HID: multitouch: take cls->maxcontacts into account for Apple Touch Bar even without a HID_DG_CONTACTMAX field

In Apple Touch Bar, the HID_DG_CONTACTMAX is not present, but the maximum
contact count is still greater than the default. Add quirks for the same.

Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Kerem Karabay <kekrby@gmail.com>
Co-developed-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

Author: kekrby

drivers/hid/hid-multitouch.c

@@ -1335,6 +1335,13 @@ static int mt_touch_input_configured(struct hid_device *hdev,
 	struct input_dev *input = hi->input;
 	int ret;
 
+	/*
+	 * HID_DG_CONTACTMAX field is not present on Apple Touch Bars,
+	 * but the maximum contact count is greater than the default.
+	 */
+	if (cls->quirks & MT_QUIRK_APPLE_TOUCHBAR && cls->maxcontacts)
+		td->maxcontacts = cls->maxcontacts;
+
 	if (!td->maxcontacts)
 		td->maxcontacts = MT_DEFAULT_MAXCONTACT;