platform/x86: uniwill-laptop: Implement rainbow animation as trigger

It turns out that some models require the lightbar to be activated
in order to display the rainbow animation, so users have to access
both the "rainbow_animation" sysfs attribute and the LED sysfs
interface when enabling the rainbow animation. This can cause short
glitches when the lightbar was previously disabled.

Fix this by replacing the sysfs attribute with a custom LED trigger
called "uniwill-rainbow". Selecting this trigger will atomically
activate the lightbar and enable the rainbow animation mode. This
can potentially break userspace applications using the old sysfs
attribute, but so far no such application is known to exist (yet).

Signed-off-by: Armin Wolf <W_Armin@gmx.de>
Link: https://patch.msgid.link/20261007144101.323289-3-W_Armin@gmx.de
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

Documentation/ABI/removed/sysfs-driver-uniwill-laptop

@@ -0,0 +1,10 @@
+What:		/sys/bus/platform/devices/INOU0000:XX/rainbow_animation
+Date:		November 2025
+KernelVersion:	6.19
+Contact:	Armin Wolf <W_Armin@gmx.de>
+Description:
+		Forces the integrated lightbar to display a rainbow animation when the machine
+		is not suspended. Writing "1"/"0" into this file enables/disables this
+		functionality.
+
+		Reading this file returns the current status of the rainbow animation functionality.

Documentation/ABI/testing/sysfs-driver-uniwill-laptop

@@ -29,17 +29,6 @@ Description:
 		Reading this file returns the current enable status of the touchpad toggle
 		functionality.
 
-What:		/sys/bus/platform/devices/INOU0000:XX/rainbow_animation
-Date:		November 2025
-KernelVersion:	6.19
-Contact:	Armin Wolf <W_Armin@gmx.de>
-Description:
-		Forces the integrated lightbar to display a rainbow animation when the machine
-		is not suspended. Writing "1"/"0" into this file enables/disables this
-		functionality.
-
-		Reading this file returns the current status of the rainbow animation functionality.
-
 What:		/sys/bus/platform/devices/INOU0000:XX/breathing_in_suspend
 Date:		November 2025
 KernelVersion:	6.19

Documentation/admin-guide/laptops/uniwill-laptop.rst

@@ -74,8 +74,9 @@ Lightbar
 The ``uniwill-laptop`` driver exposes the lightbar found on some models as a standard multicolor
 LED class device. The default name of this LED class device is ``uniwill:multicolor:status``.
 
-See Documentation/ABI/testing/sysfs-driver-uniwill-laptop for details on how to control the various
-animation modes of the lightbar.
+The lightbar supports a separate rainbow animation mode that can be enabled by selecting the
+`uniwill-rainbow` LED trigger. To enable a breathing animation during suspend, see
+Documentation/ABI/testing/sysfs-driver-uniwill-laptop for details.
 
 Keyboard Backlight
 ------------------

MAINTAINERS

@@ -28106,6 +28106,7 @@ UNIWILL LAPTOP DRIVER
 M:	Armin Wolf <W_Armin@gmx.de>
 L:	platform-driver-x86@vger.kernel.org
 S:	Maintained
+F:	Documentation/ABI/removed/sysfs-driver-uniwill-laptop
 F:	Documentation/ABI/testing/sysfs-driver-uniwill-laptop
 F:	Documentation/admin-guide/laptops/uniwill-laptop.rst
 F:	Documentation/wmi/devices/uniwill-laptop.rst

drivers/platform/x86/uniwill/Kconfig

@@ -28,6 +28,7 @@ config UNIWILL_LAPTOP
 	depends on DMI
 	select REGMAP
 	select INPUT_SPARSEKMAP
+	select LEDS_TRIGGERS
 	help
 	  This driver adds support for various extra features found on Uniwill laptops,
 	  like the lightbar, hwmon sensors and hotkeys. It also supports many OEM laptops

drivers/platform/x86/uniwill/uniwill-acpi.c

@@ -903,51 +903,6 @@ static ssize_t touchpad_toggle_enable_show(struct device *dev, struct device_att
 
 static DEVICE_ATTR_RW(touchpad_toggle_enable);
 
-static ssize_t rainbow_animation_store(struct device *dev, struct device_attribute *attr,
-				       const char *buf, size_t count)
-{
-	struct uniwill_data *data = dev_get_drvdata(dev);
-	unsigned int value;
-	bool enable;
-	int ret;
-
-	ret = kstrtobool(buf, &enable);
-	if (ret < 0)
-		return ret;
-
-	if (enable)
-		value = LIGHTBAR_WELCOME;
-	else
-		value = 0;
-
-	guard(mutex)(&data->led_lock);
-
-	ret = regmap_update_bits(data->regmap, EC_ADDR_LIGHTBAR_AC_CTRL, LIGHTBAR_WELCOME, value);
-	if (ret < 0)
-		return ret;
-
-	ret = regmap_update_bits(data->regmap, EC_ADDR_LIGHTBAR_BAT_CTRL, LIGHTBAR_WELCOME, value);
-	if (ret < 0)
-		return ret;
-
-	return count;
-}
-
-static ssize_t rainbow_animation_show(struct device *dev, struct device_attribute *attr, char *buf)
-{
-	struct uniwill_data *data = dev_get_drvdata(dev);
-	unsigned int value;
-	int ret;
-
-	ret = regmap_read(data->regmap, EC_ADDR_LIGHTBAR_AC_CTRL, &value);
-	if (ret < 0)
-		return ret;
-
-	return sysfs_emit(buf, "%d\n", !!(value & LIGHTBAR_WELCOME));
-}
-
-static DEVICE_ATTR_RW(rainbow_animation);
-
 static ssize_t breathing_in_suspend_store(struct device *dev, struct device_attribute *attr,
 					  const char *buf, size_t count)
 {
@@ -1261,7 +1216,6 @@ static struct attribute *uniwill_attrs[] = {
 	&dev_attr_super_key_enable.attr,
 	&dev_attr_touchpad_toggle_enable.attr,
 	/* Lightbar-related */
-	&dev_attr_rainbow_animation.attr,
 	&dev_attr_breathing_in_suspend.attr,
 	/* Power-management-related */
 	&dev_attr_ctgp_offset.attr,
@@ -1291,8 +1245,7 @@ static umode_t uniwill_attr_is_visible(struct kobject *kobj, struct attribute *a
 			return attr->mode;
 	}
 
-	if (attr == &dev_attr_rainbow_animation.attr ||
-	    attr == &dev_attr_breathing_in_suspend.attr) {
+	if (attr == &dev_attr_breathing_in_suspend.attr) {
 		if (uniwill_device_supports(data, UNIWILL_FEATURE_LIGHTBAR))
 			return attr->mode;
 	}
@@ -1540,6 +1493,59 @@ static int uniwill_led_brightness_set(struct led_classdev *led_cdev, enum led_br
 	return regmap_update_bits(data->regmap, EC_ADDR_LIGHTBAR_BAT_CTRL, LIGHTBAR_S0_OFF, value);
 }
 
+static int uniwill_led_hw_control_set(struct led_classdev *led_cdev, unsigned long flags)
+{
+	struct led_classdev_mc *led_mc_cdev = lcdev_to_mccdev(led_cdev);
+	struct uniwill_data *data = container_of(led_mc_cdev, struct uniwill_data, led_mc_cdev);
+	unsigned int value;
+	int ret;
+
+	guard(mutex)(&data->led_lock);
+
+	if (flags)
+		value = LIGHTBAR_WELCOME;
+	else
+		value = LIGHTBAR_S0_OFF;
+
+	ret = regmap_update_bits(data->regmap, EC_ADDR_LIGHTBAR_AC_CTRL,
+				 LIGHTBAR_S0_OFF | LIGHTBAR_WELCOME, value);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_update_bits(data->regmap, EC_ADDR_LIGHTBAR_BAT_CTRL,
+				 LIGHTBAR_S0_OFF | LIGHTBAR_WELCOME, value);
+	if (ret < 0)
+		return ret;
+
+	/* The LED is always on during hw control */
+	led_cdev->brightness = flags;
+
+	return 0;
+}
+
+static int uniwill_lightbar_trigger_activate(struct led_classdev *led_cdev)
+{
+	return led_cdev->hw_control_set(led_cdev, 1);
+}
+
+static void uniwill_lightbar_trigger_deactivate(struct led_classdev *led_cdev)
+{
+	int ret;
+
+	ret = led_cdev->hw_control_set(led_cdev, 0);
+	if (ret < 0)
+		dev_err(led_cdev->dev, "Failed to stop rainbow animation: %d\n", ret);
+}
+
+static struct led_hw_trigger_type uniwill_lightbar_trigger_type;
+
+static struct led_trigger uniwill_lightbar_trigger = {
+	.name = "uniwill-rainbow",
+	.activate = uniwill_lightbar_trigger_activate,
+	.deactivate = uniwill_lightbar_trigger_deactivate,
+	.trigger_type = &uniwill_lightbar_trigger_type,
+};
+
 #define LIGHTBAR_MASK	(LIGHTBAR_APP_EXISTS | LIGHTBAR_S0_OFF | LIGHTBAR_S3_OFF | LIGHTBAR_WELCOME)
 
 static int uniwill_led_init(struct uniwill_data *data)
@@ -1590,12 +1596,18 @@ static int uniwill_led_init(struct uniwill_data *data)
 	data->led_mc_cdev.led_cdev.max_brightness = 1;
 	data->led_mc_cdev.led_cdev.flags = LED_REJECT_NAME_CONFLICT;
 	data->led_mc_cdev.led_cdev.brightness_set_blocking = uniwill_led_brightness_set;
+	data->led_mc_cdev.led_cdev.trigger_type = &uniwill_lightbar_trigger_type;
+	data->led_mc_cdev.led_cdev.hw_control_trigger = uniwill_lightbar_trigger.name;
+	data->led_mc_cdev.led_cdev.hw_control_set = uniwill_led_hw_control_set;
 
 	if (value & LIGHTBAR_S0_OFF)
 		data->led_mc_cdev.led_cdev.brightness = 0;
 	else
 		data->led_mc_cdev.led_cdev.brightness = 1;
 
+	if (value & LIGHTBAR_WELCOME)
+		data->led_mc_cdev.led_cdev.default_trigger = uniwill_lightbar_trigger.name;
+
 	for (int i = 0; i < LED_CHANNELS; i++) {
 		data->led_mc_subled_info[i].color_index = color_indices[i];
 
@@ -3551,17 +3563,31 @@ static int __init uniwill_init(void)
 		pr_warn("Enabling potentially unsupported features\n");
 	}
 
-	ret = platform_driver_register(&uniwill_driver);
+	/*
+	 * We cannot register the trigger inside the .probe callback of the
+	 * platform driver, because each trigger needs a unique name.
+	 */
+	ret = led_trigger_register(&uniwill_lightbar_trigger);
 	if (ret < 0)
 		return ret;
 
+	ret = platform_driver_register(&uniwill_driver);
+	if (ret < 0)
+		goto err_platform;
+
 	ret = uniwill_wmi_register_driver();
-	if (ret < 0) {
-		platform_driver_unregister(&uniwill_driver);
-		return ret;
-	}
+	if (ret < 0)
+		goto err_wmi;
 
 	return 0;
+
+err_wmi:
+	platform_driver_unregister(&uniwill_driver);
+
+err_platform:
+	led_trigger_unregister(&uniwill_lightbar_trigger);
+
+	return ret;
 }
 module_init(uniwill_init);
 
@@ -3569,6 +3595,7 @@ static void __exit uniwill_exit(void)
 {
 	uniwill_wmi_unregister_driver();
 	platform_driver_unregister(&uniwill_driver);
+	led_trigger_unregister(&uniwill_lightbar_trigger);
 }
 module_exit(uniwill_exit);