platform/x86: fujitsu-laptop: switch to a managed backlight device

Use a managed backlight device to get rid of acpi_fujitsu_bl_remove().
Change the parent of the backlight device from NULL to the FUJ02B1 ACPI
device as the latter is required for the backlight device to work.
Signed-off-by: Michał Kępień <kernel@kempniu.pl>
Reviewed-by: Jonathan Woithe <jwoithe@just42.net>
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>

drivers/platform/x86/fujitsu-laptop.c

@@ -550,16 +550,17 @@ static int acpi_fujitsu_bl_input_setup(struct acpi_device *device)
 	return input_register_device(fujitsu_bl->input);
 }
 
-static int fujitsu_backlight_register(void)
+static int fujitsu_backlight_register(struct acpi_device *device)
 {
-	struct backlight_properties props = {
+	const struct backlight_properties props = {
 		.brightness = fujitsu_bl->brightness_level,
 		.max_brightness = fujitsu_bl->max_brightness - 1,
 		.type = BACKLIGHT_PLATFORM
 	};
 	struct backlight_device *bd;
 
-	bd = backlight_device_register("fujitsu-laptop", NULL, NULL,
+	bd = devm_backlight_device_register(&device->dev, "fujitsu-laptop",
+					    &device->dev, NULL,
 					    &fujitsu_bl_ops, &props);
 	if (IS_ERR(bd))
 		return PTR_ERR(bd);
@@ -629,24 +630,13 @@ static int acpi_fujitsu_bl_add(struct acpi_device *device)
 		fujitsu_bl->max_brightness = FUJITSU_LCD_N_LEVELS;
 	get_lcd_level();
 
-	error = fujitsu_backlight_register();
+	error = fujitsu_backlight_register(device);
 	if (error)
 		return error;
 
 	return 0;
 }
 
-static int acpi_fujitsu_bl_remove(struct acpi_device *device)
-{
-	struct fujitsu_bl *fujitsu_bl = acpi_driver_data(device);
-
-	backlight_device_unregister(fujitsu_bl->bl_device);
-
-	fujitsu_bl->acpi_handle = NULL;
-
-	return 0;
-}
-
 /* Brightness notify */
 
 static void acpi_fujitsu_bl_notify(struct acpi_device *device, u32 event)
@@ -1077,7 +1067,6 @@ static struct acpi_driver acpi_fujitsu_bl_driver = {
 	.ids = fujitsu_bl_device_ids,
 	.ops = {
 		.add = acpi_fujitsu_bl_add,
-		.remove = acpi_fujitsu_bl_remove,
 		.notify = acpi_fujitsu_bl_notify,
 		},
 };