platform/x86: dell-privacy: Only register SW_CAMERA_LENS_COVER if present

commit 6dc485f994 upstream.

Unlike keys where userspace only reacts to keypresses, userspace may act
on switches in both (0 and 1) of their positions.

For example if a SW_TABLET_MODE switch is registered then GNOME will not
automatically show the onscreen keyboard when a text field gets focus on
touchscreen devices when SW_TABLET_MODE reports 0 and when SW_TABLET_MODE
reports 1 libinput will block (filter out) builtin keyboard and touchpad
events.

So to avoid unwanted side-effects EV_SW type inputs should only be
registered if they are actually present, only register SW_CAMERA_LENS_COVER
if it is actually there.

Fixes: 8af9fa37b8 ("platform/x86: dell-privacy: Add support for Dell hardware privacy")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20221221220724.119594-2-hdegoede@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/platform/x86/dell/dell-wmi-privacy.c

@@ -295,7 +295,7 @@ static int dell_privacy_wmi_probe(struct wmi_device *wdev, const void *context)
 {
 	struct privacy_wmi_data *priv;
 	struct key_entry *keymap;
-	int ret, i;
+	int ret, i, j;
 
 	ret = wmi_has_guid(DELL_PRIVACY_GUID);
 	if (!ret)
@@ -321,9 +321,20 @@ static int dell_privacy_wmi_probe(struct wmi_device *wdev, const void *context)
 	/* remap the keymap code with Dell privacy key type 0x12 as prefix
 	 * KEY_MICMUTE scancode will be reported as 0x120001
 	 */
-	for (i = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
-		keymap[i] = dell_wmi_keymap_type_0012[i];
-		keymap[i].code |= (0x0012 << 16);
+	for (i = 0, j = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
+		/*
+		 * Unlike keys where only presses matter, userspace may act
+		 * on switches in both of their positions. Only register
+		 * SW_CAMERA_LENS_COVER if it is actually there.
+		 */
+		if (dell_wmi_keymap_type_0012[i].type == KE_VSW &&
+		    dell_wmi_keymap_type_0012[i].sw.code == SW_CAMERA_LENS_COVER &&
+		    !(priv->features_present & BIT(DELL_PRIVACY_TYPE_CAMERA)))
+			continue;
+
+		keymap[j] = dell_wmi_keymap_type_0012[i];
+		keymap[j].code |= (0x0012 << 16);
+		j++;
 	}
 	ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
 	kfree(keymap);