platform/x86: asus-wmi: Move i8042 filter install to shared asus-wmi code

asus-nb-wmi calls i8042_install_filter() in some cases, but it never
calls i8042_remove_filter(). This means that a dangling pointer to
the filter function is left after rmmod leading to crashes.

Fix this by moving the i8042-filter installation to the shared
asus-wmi code and also remove it from the shared code on driver unbind.

Fixes: b564353 ("platform/x86: asus-wmi: Filter buggy scan codes on ASUS Q500A")
Cc: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20231120154235.610808-2-hdegoede@redhat.com
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Author: jwrdegoede

drivers/platform/x86/Kconfig

@@ -263,6 +263,7 @@ config ASUS_WMI
 	depends on RFKILL || RFKILL = n
 	depends on HOTPLUG_PCI
 	depends on ACPI_VIDEO || ACPI_VIDEO = n
+	depends on SERIO_I8042 || SERIO_I8042 = n
 	select INPUT_SPARSEKMAP
 	select LEDS_CLASS
 	select NEW_LEDS
@@ -279,7 +280,6 @@ config ASUS_WMI
 config ASUS_NB_WMI
 	tristate "Asus Notebook WMI Driver"
 	depends on ASUS_WMI
-	depends on SERIO_I8042 || SERIO_I8042 = n
 	help
 	  This is a driver for newer Asus notebooks. It adds extra features
 	  like wireless radio and bluetooth control, leds, hotkeys, backlight...

drivers/platform/x86/asus-nb-wmi.c

@@ -503,8 +503,6 @@ static const struct dmi_system_id asus_quirks[] = {
 
 static void asus_nb_wmi_quirks(struct asus_wmi_driver *driver)
 {
-	int ret;
-
 	quirks = &quirk_asus_unknown;
 	dmi_check_system(asus_quirks);
 
@@ -519,15 +517,6 @@ static void asus_nb_wmi_quirks(struct asus_wmi_driver *driver)
 
 	if (tablet_mode_sw != -1)
 		quirks->tablet_switch_mode = tablet_mode_sw;
-
-	if (quirks->i8042_filter) {
-		ret = i8042_install_filter(quirks->i8042_filter);
-		if (ret) {
-			pr_warn("Unable to install key filter\n");
-			return;
-		}
-		pr_info("Using i8042 filter function for receiving events\n");
-	}
 }
 
 static const struct key_entry asus_nb_wmi_keymap[] = {

drivers/platform/x86/asus-wmi.c

@@ -4567,6 +4567,12 @@ static int asus_wmi_add(struct platform_device *pdev)
 		goto fail_wmi_handler;
 	}
 
+	if (asus->driver->quirks->i8042_filter) {
+		err = i8042_install_filter(asus->driver->quirks->i8042_filter);
+		if (err)
+			pr_warn("Unable to install key filter - %d\n", err);
+	}
+
 	asus_wmi_battery_init(asus);
 
 	asus_wmi_debugfs_init(asus);
@@ -4603,6 +4609,8 @@ static int asus_wmi_remove(struct platform_device *device)
 	struct asus_wmi *asus;
 
 	asus = platform_get_drvdata(device);
+	if (asus->driver->quirks->i8042_filter)
+		i8042_remove_filter(asus->driver->quirks->i8042_filter);
 	wmi_remove_notify_handler(asus->driver->event_guid);
 	asus_wmi_backlight_exit(asus);
 	asus_screenpad_exit(asus);