HID: wacom: set initial hardware touch switch state to 'off'

Wacom touch devices have two types of touch switches: softkey touch
toggle and hardware touch switch. For softkey toggle, we assume
touch is on by default in the driver. However the hardware touch
switch is controlled by end users. We don't know if it's on or off
before getting the status event.

This patch sets touch off for devices with a hardware switch until we
get the status. This is a bit safer for users who leave the switch "off"
and don't want any accidental touches. The tradeoff is a slight delay
between device connection and touch becoming enabled for users who
leave the switch "on".

Signed-off-by: Ping Cheng <ping.cheng@wacom.com>
Reviewed-by: Jason Gerecke <jason.gerecke@wacom.com>
Tested-by: Jason Gerecke <jason.gerecke@wacom.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Author: Ping Cheng

drivers/hid/wacom_sys.c

@@ -2287,7 +2287,13 @@ static void wacom_set_shared_values(struct wacom_wac *wacom_wac)
 
 	if (wacom_wac->has_mute_touch_switch) {
 		wacom_wac->shared->has_mute_touch_switch = true;
-		wacom_wac->shared->is_touch_on = true;
+		/* Hardware touch switch may be off. Wait until
+		 * we know the switch state to decide is_touch_on.
+		 * Softkey state should be initialized to "on" to
+		 * match historic default.
+		 */
+		if (wacom_wac->is_soft_touch_switch)
+			wacom_wac->shared->is_touch_on = true;
 	}
 
 	if (wacom_wac->shared->has_mute_touch_switch &&

drivers/hid/wacom_wac.c

@@ -1987,14 +1987,17 @@ static void wacom_wac_pad_usage_mapping(struct hid_device *hdev,
 		features->numbered_buttons++;
 		features->device_type |= WACOM_DEVICETYPE_PAD;
 		break;
-	case WACOM_HID_WD_TOUCHONOFF:
 	case WACOM_HID_WD_MUTE_DEVICE:
+		/* softkey touch switch */
+		wacom_wac->is_soft_touch_switch = true;
+		fallthrough;
+	case WACOM_HID_WD_TOUCHONOFF:
 		/*
-		 * This usage, which is used to mute touch events, comes
-		 * from the pad packet, but is reported on the touch
+		 * These two usages, which are used to mute touch events, come
+		 * from the pad packet, but are reported on the touch
 		 * interface. Because the touch interface may not have
 		 * been created yet, we cannot call wacom_map_usage(). In
-		 * order to process this usage when we receive it, we set
+		 * order to process the usages when we receive them, we set
 		 * the usage type and code directly.
 		 */
 		wacom_wac->has_mute_touch_switch = true;
@@ -3835,6 +3838,7 @@ int wacom_setup_touch_input_capabilities(struct input_dev *input_dev,
 			input_dev->evbit[0] |= BIT_MASK(EV_SW);
 			__set_bit(SW_MUTE_DEVICE, input_dev->swbit);
 			wacom_wac->has_mute_touch_switch = true;
+			wacom_wac->is_soft_touch_switch = true;
 		}
 		fallthrough;
 

drivers/hid/wacom_wac.h

@@ -352,6 +352,7 @@ struct wacom_wac {
 	int mode_value;
 	struct hid_data hid_data;
 	bool has_mute_touch_switch;
+	bool is_soft_touch_switch;
 	bool has_mode_change;
 	bool is_direct_mode;
 	bool is_invalid_bt_frame;