HID: wacom: Don't register pad_input for touch switch

Touch switch state is received through WACOM_PAD_FIELD. However, it
is reported by touch_input. Don't register pad_input if no other pad
events require the interface.

Cc: stable@vger.kernel.org
Signed-off-by: NPing Cheng <ping.cheng@wacom.com>
Reviewed-by: NJason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

drivers/hid/wacom_sys.c

@@ -2121,7 +2121,7 @@ static int wacom_register_inputs(struct wacom *wacom)
 
 	error = wacom_setup_pad_input_capabilities(pad_input_dev, wacom_wac);
 	if (error) {
-		/* no pad in use on this interface */
+		/* no pad events using this interface */
 		input_free_device(pad_input_dev);
 		wacom_wac->pad_input = NULL;
 		pad_input_dev = NULL;

drivers/hid/wacom_wac.c

@@ -2019,7 +2019,6 @@ static void wacom_wac_pad_usage_mapping(struct hid_device *hdev,
 		wacom_wac->has_mute_touch_switch = true;
 		usage->type = EV_SW;
 		usage->code = SW_MUTE_DEVICE;
-		features->device_type |= WACOM_DEVICETYPE_PAD;
 		break;
 	case WACOM_HID_WD_TOUCHSTRIP:
 		wacom_map_usage(input, usage, field, EV_ABS, ABS_RX, 0);
@@ -2099,6 +2098,30 @@ static void wacom_wac_pad_event(struct hid_device *hdev, struct hid_field *field
 			wacom_wac->hid_data.inrange_state |= value;
 	}
 
+	/* Process touch switch state first since it is reported through touch interface,
+	 * which is indepentent of pad interface. In the case when there are no other pad
+	 * events, the pad interface will not even be created.
+	 */
+	if ((equivalent_usage == WACOM_HID_WD_MUTE_DEVICE) ||
+	   (equivalent_usage == WACOM_HID_WD_TOUCHONOFF)) {
+		if (wacom_wac->shared->touch_input) {
+			bool *is_touch_on = &wacom_wac->shared->is_touch_on;
+
+			if (equivalent_usage == WACOM_HID_WD_MUTE_DEVICE && value)
+				*is_touch_on = !(*is_touch_on);
+			else if (equivalent_usage == WACOM_HID_WD_TOUCHONOFF)
+				*is_touch_on = value;
+
+			input_report_switch(wacom_wac->shared->touch_input,
+					    SW_MUTE_DEVICE, !(*is_touch_on));
+			input_sync(wacom_wac->shared->touch_input);
+		}
+		return;
+	}
+
+	if (!input)
+		return;
+
 	switch (equivalent_usage) {
 	case WACOM_HID_WD_TOUCHRING:
 		/*
@@ -2134,22 +2157,6 @@ static void wacom_wac_pad_event(struct hid_device *hdev, struct hid_field *field
 			input_event(input, usage->type, usage->code, 0);
 		break;
 
-	case WACOM_HID_WD_MUTE_DEVICE:
-	case WACOM_HID_WD_TOUCHONOFF:
-		if (wacom_wac->shared->touch_input) {
-			bool *is_touch_on = &wacom_wac->shared->is_touch_on;
-
-			if (equivalent_usage == WACOM_HID_WD_MUTE_DEVICE && value)
-				*is_touch_on = !(*is_touch_on);
-			else if (equivalent_usage == WACOM_HID_WD_TOUCHONOFF)
-				*is_touch_on = value;
-
-			input_report_switch(wacom_wac->shared->touch_input,
-					    SW_MUTE_DEVICE, !(*is_touch_on));
-			input_sync(wacom_wac->shared->touch_input);
-		}
-		break;
-
 	case WACOM_HID_WD_MODE_CHANGE:
 		if (wacom_wac->is_direct_mode != value) {
 			wacom_wac->is_direct_mode = value;
@@ -2835,7 +2842,7 @@ void wacom_wac_event(struct hid_device *hdev, struct hid_field *field,
 	/* usage tests must precede field tests */
 	if (WACOM_BATTERY_USAGE(usage))
 		wacom_wac_battery_event(hdev, field, usage, value);
-	else if (WACOM_PAD_FIELD(field) && wacom->wacom_wac.pad_input)
+	else if (WACOM_PAD_FIELD(field))
 		wacom_wac_pad_event(hdev, field, usage, value);
 	else if (WACOM_PEN_FIELD(field) && wacom->wacom_wac.pen_input)
 		wacom_wac_pen_event(hdev, field, usage, value);