HID: lenovo: Use brightness_set_blocking callback for setting LEDs brightness

The lenovo_led_brightness_set function may sleep, so we should have the
the led_class_dev's brightness_set_blocking callback point to it, rather
then the regular brightness_set callback.

When toggled through sysfs this is not a problem, but the brightness_set
callback may be called from atomic context when using LED-triggers.

Fixes: bc04b37 ("HID: lenovo: Add ThinkPad 10 Ultrabook Keyboard support")
Reviewed-by: Marek Behún <kabel@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Author: jwrdegoede

drivers/hid/hid-lenovo.c

@@ -777,7 +777,7 @@ static enum led_brightness lenovo_led_brightness_get(
 				: LED_OFF;
 }
 
-static void lenovo_led_brightness_set(struct led_classdev *led_cdev,
+static int lenovo_led_brightness_set(struct led_classdev *led_cdev,
 			enum led_brightness value)
 {
 	struct device *dev = led_cdev->dev->parent;
@@ -802,6 +802,8 @@ static void lenovo_led_brightness_set(struct led_classdev *led_cdev,
 		lenovo_led_set_tp10ubkbd(hdev, tp10ubkbd_led[led_nr], value);
 		break;
 	}
+
+	return 0;
 }
 
 static int lenovo_register_leds(struct hid_device *hdev)
@@ -822,15 +824,15 @@ static int lenovo_register_leds(struct hid_device *hdev)
 
 	data->led_mute.name = name_mute;
 	data->led_mute.brightness_get = lenovo_led_brightness_get;
-	data->led_mute.brightness_set = lenovo_led_brightness_set;
+	data->led_mute.brightness_set_blocking = lenovo_led_brightness_set;
 	data->led_mute.dev = &hdev->dev;
 	ret = led_classdev_register(&hdev->dev, &data->led_mute);
 	if (ret < 0)
 		return ret;
 
 	data->led_micmute.name = name_micm;
 	data->led_micmute.brightness_get = lenovo_led_brightness_get;
-	data->led_micmute.brightness_set = lenovo_led_brightness_set;
+	data->led_micmute.brightness_set_blocking = lenovo_led_brightness_set;
 	data->led_micmute.dev = &hdev->dev;
 	ret = led_classdev_register(&hdev->dev, &data->led_micmute);
 	if (ret < 0) {