[PATCH v3 1/2] platform/x86: hp-wmi: Add multicolor LED support for HP keyboard backlight

edip
2026-02-28T12:27:04Z

From: Edip Hazuri <edip@medip.dev>

Add support for the HP keyboard RGB backlight found on HP OMEN and
HP Victus laptops. These keyboards expose per-zone RGB control through
WMI commands.

Register multicolor LED class devices for each keyboard zone (up to 4
zones, depending on the keyboard type). Each zone exposes individual
red, green, and blue channels via the multicolor LED subsystem.

Also hardware-initiated brightness changes (e.g. via the keyboard
backlight
hotkey,mostly fn+f4) are reported

The color data is stored in a 128-byte color table managed by the
firmware, with RGB values starting at offset 25, packed sequentially
per zone.

Signed-off-by: Edip Hazuri <edip@medip.dev>
---
v1: https://lore.kernel.org/all/20260227063122.7184-2-edip@medip.dev/
v3 because i sent v2 by mistake, please do not review v2.

Changes since v1:
- Fix mentioned style errors
- Add Kconfig dependencies

drivers/platform/x86/hp/hp-wmi.c | 274 +++++++++++++++++++++++++++++++
1 file changed, 274 insertions(+)

diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
index 304d9ac63c8a..4a378ebe9be4 100644
--- a/drivers/platform/x86/hp/hp-wmi.c
+++ b/drivers/platform/x86/hp/hp-wmi.c
@@ -14,6 +14,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/acpi.h>
+#include <linux/array_size.h>
#include <linux/cleanup.h>
#include <linux/compiler_attributes.h>
#include <linux/dmi.h>
@@ -23,6 +24,8 @@
#include <linux/input.h>
#include <linux/input/sparse-keymap.h>
#include <linux/kernel.h>
+#include <linux/led-class-multicolor.h>
+#include <linux/leds.h>
#include <linux/limits.h>
#include <linux/minmax.h>
#include <linux/module.h>
@@ -58,6 +61,8 @@ enum hp_ec_offsets {
#define HP_POWER_LIMIT_DEFAULT 0x00
#define HP_POWER_LIMIT_NO_CHANGE 0xFF

+#define HP_COLOR_TABLE_PADDING 25
+
#define ACPI_AC_CLASS "ac_adapter"

#define zero_if_sup(tmp) (zero_insize_support?0:sizeof(tmp)) // use when zero insize is required
@@ -98,6 +103,15 @@ enum hp_thermal_profile {
HP_THERMAL_PROFILE_QUIET = 0x03,
};

+enum hp_keyboard_type {
+ HP_KEYBOARD_TYPE_NOBACKLIGHT = 0x0,
+ HP_KEYBOARD_TYPE_FOURZONE_WITH_NUMPAD = 0x1,
+ HP_KEYBOARD_TYPE_FOURZONE_WITHOUT_NUMPAD = 0x2,
+ HP_KEYBOARD_TYPE_RGB_PER_KEY = 0x3,
+ HP_KEYBOARD_TYPE_SINGLEZONE_WITH_NUMPAD = 0x4,
+ HP_KEYBOARD_TYPE_SINGLEZONE_WITHOUT_NUMPAD = 0x5,
+};
+

struct thermal_profile_params {
u8 performance;
@@ -290,16 +304,27 @@ enum hp_wmi_gm_commandtype {
HPWMI_GET_GPU_THERMAL_MODES_QUERY = 0x21,
HPWMI_SET_GPU_THERMAL_MODES_QUERY = 0x22,
HPWMI_SET_POWER_LIMITS_QUERY = 0x29,
+ HPWMI_GET_KEYBOARD_TYPE_QUERY = 0x2b,
HPWMI_VICTUS_S_FAN_SPEED_GET_QUERY = 0x2D,
HPWMI_VICTUS_S_FAN_SPEED_SET_QUERY = 0x2E,
HPWMI_VICTUS_S_GET_FAN_TABLE_QUERY = 0x2F,
};

+enum hp_wmi_backlight_commandtype {
+ HPWMI_BACKLIGHT_COLOR_GET_QUERY = 0x02,
+ HPWMI_BACKLIGHT_COLOR_SET_QUERY = 0x03,
+ HPWMI_BACKLIGHT_BRIGHTNESS_GET_QUERY = 0x04,
+ HPWMI_BACKLIGHT_BRIGHTNESS_SET_QUERY = 0x05,
+ HPWMI_BACKLIGHT_SET_OFF_QUERY = 0x64,
+ HPWMI_BACKLIGHT_SET_ON_QUERY = 0xE4,
+};
+
enum hp_wmi_command {
HPWMI_READ = 0x01,
HPWMI_WRITE = 0x02,
HPWMI_ODM = 0x03,
HPWMI_GM = 0x20008,
+ HPWMI_BACKLIGHT = 0x20009,
};

enum hp_wmi_hardware_mask {
@@ -373,6 +398,16 @@ static const struct key_entry hp_wmi_keymap[] = {
{ KE_END, 0 }
};

+struct hp_kbd_led_priv {
+ int zone; /* Zone index (0-3) */
+ enum led_brightness last_brightness; /* Brightness before turning off */
+};
+
+struct hp_mc_leds {
+ struct led_classdev_mc devices[4];
+ struct hp_kbd_led_priv priv[4];
+};
+
/*
* Mutex for the active_platform_profile variable,
* see omen_powersource_event.
@@ -382,6 +417,7 @@ static DEFINE_MUTEX(active_platform_profile_lock);
static struct input_dev *hp_wmi_input_dev;
static struct input_dev *camera_shutter_input_dev;
static struct platform_device *hp_wmi_platform_dev;
+static struct hp_mc_leds hp_multicolor_leds;
static struct device *platform_profile_device;
static struct notifier_block platform_power_source_nb;
static enum platform_profile_option active_platform_profile;
@@ -1068,6 +1104,8 @@ static struct attribute *hp_wmi_attrs[] = {
};
ATTRIBUTE_GROUPS(hp_wmi);

+static void hp_kbd_brightness_set_by_hwd(u32 event_data);
+
static void hp_wmi_notify(union acpi_object *obj, void *context)
{
u32 event_id, event_data;
@@ -1168,6 +1206,7 @@ static void hp_wmi_notify(union acpi_object *obj, void *context)
case HPWMI_PROXIMITY_SENSOR:
break;
case HPWMI_BACKLIT_KB_BRIGHTNESS:
+ hp_kbd_brightness_set_by_hwd(event_data);
break;
case HPWMI_PEAKSHIFT_PERIOD:
break;
@@ -1430,6 +1469,237 @@ static int __init hp_wmi_rfkill2_setup(struct platform_device *device)
return err;
}

+static struct hp_kbd_led_priv *hp_led_get_priv(struct led_classdev *led_cdev)
+{
+ struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(led_cdev);
+ int zone = mc_cdev - hp_multicolor_leds.devices;
+
+ return &hp_multicolor_leds.priv[zone];
+}
+
+static int hp_kbd_backlight_set_rgb_color(int zone, int red, int green, int blue)
+{
+ u8 color_table[128];
+ int ret;
+
+ /*
+ * Get the current color table and then change only the relevant parts.
+ */
+ ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_COLOR_GET_QUERY,
+ HPWMI_BACKLIGHT, color_table,
+ zero_if_sup(color_table),
+ sizeof(color_table));
+ if (ret)
+ return ret;
+
+ /*
+ * RGB color data starts at offset 25 +3 per zone (r g b)
+ * e.g. if zone 1 starts in 25 zone 2 starts in 28
+ */
+ color_table[HP_COLOR_TABLE_PADDING + zone * 3] = red;
+ color_table[HP_COLOR_TABLE_PADDING + zone * 3 + 1] = green;
+ color_table[HP_COLOR_TABLE_PADDING + zone * 3 + 2] = blue;
+
+ ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_COLOR_SET_QUERY, HPWMI_BACKLIGHT,
+ color_table, sizeof(color_table), sizeof(color_table));
+ if (ret < 0)
+ return ret;
+ if (ret)
+ return -EINVAL;
+
+ return 0;
+}
+
+static bool hp_kbd_backlight_is_on(void)
+{
+ u8 data;
+ int ret;
+
+ ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_BRIGHTNESS_GET_QUERY, HPWMI_BACKLIGHT, &data,
+ sizeof(data), sizeof(data));
+ if (ret)
+ return false;
+
+ return data == HPWMI_BACKLIGHT_SET_ON_QUERY;
+}
+
+static int hp_kbd_set_brightness(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct hp_kbd_led_priv *priv = hp_led_get_priv(led_cdev);
+ struct led_classdev_mc *mc_cdev;
+ struct led_classdev_mc *device;
+ int red, green, blue;
+ int ret;
+
+ if (!hp_kbd_backlight_is_on()) {
+ u8 data = HPWMI_BACKLIGHT_SET_ON_QUERY;
+
+ ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_BRIGHTNESS_SET_QUERY,
+ HPWMI_BACKLIGHT, &data,
+ sizeof(data), sizeof(data));
+ if (ret)
+ return ret;
+
+ /*
+ * Turning the backlight on via WMI turns all zones,
+ * so we need to restore the other zones' off state.
+ */
+ for (int i = 0; i < ARRAY_SIZE(hp_multicolor_leds.devices); i++) {
+ if (i == priv->zone)
+ continue;
+
+ device = &hp_multicolor_leds.devices[i];
+ if (!device->led_cdev.name)
+ continue;
+ hp_kbd_backlight_set_rgb_color(i,
+ device->subled_info[0].brightness,
+ device->subled_info[1].brightness,
+ device->subled_info[2].brightness);
+ }
+ }
+
+ led_cdev->brightness = brightness;
+
+ mc_cdev = lcdev_to_mccdev(led_cdev);
+ led_mc_calc_color_components(mc_cdev, brightness);
+
+ red = mc_cdev->subled_info[0].brightness;
+ green = mc_cdev->subled_info[1].brightness;
+ blue = mc_cdev->subled_info[2].brightness;
+
+ return hp_kbd_backlight_set_rgb_color(priv->zone, red, green, blue);
+}
+
+static void hp_kbd_brightness_set_by_hwd(u32 event_data)
+{
+ struct device *dev = &hp_wmi_platform_dev->dev;
+ struct led_classdev *led_cdev;
+ struct hp_kbd_led_priv *priv;
+ u8 brightness;
+
+ for (int zone = 0; zone < ARRAY_SIZE(hp_multicolor_leds.devices); zone++) {
+ if (!hp_multicolor_leds.devices[zone].led_cdev.name)
+ continue;
+
+ led_cdev = &hp_multicolor_leds.devices[zone].led_cdev;
+ if (!led_cdev->dev)
+ continue;
+
+ priv = hp_led_get_priv(led_cdev);
+
+ if (event_data == 0x2) {
+ brightness = priv->last_brightness ? : LED_FULL;
+ } else if (event_data == 0x0) {
+ priv->last_brightness = led_cdev->brightness;
+ brightness = LED_OFF;
+ } else {
+ dev_warn(dev, "Unknown keyboard backlight event - 0x%x\n",
+ event_data);
+ return;
+ }
+
+ led_cdev->brightness = brightness;
+ led_classdev_notify_brightness_hw_changed(led_cdev, brightness);
+ }
+}
+
+static int __init hp_mc_leds_register(int num_zones)
+{
+ u8 color_table[128];
+ int ret;
+
+ ret = hp_wmi_perform_query(HPWMI_BACKLIGHT_COLOR_GET_QUERY, HPWMI_BACKLIGHT,
+ color_table, zero_if_sup(color_table),
+ sizeof(color_table));
+ if (ret)
+ return ret;
+
+ for (int zone = 0; zone < num_zones; zone++) {
+ struct led_classdev_mc *multicolor_led_dev;
+ struct led_classdev *led_cdev;
+ struct mc_subled *mc_subled_info;
+ struct hp_kbd_led_priv *priv;
+ struct device *dev;
+
+ dev = &hp_wmi_platform_dev->dev;
+ multicolor_led_dev = &hp_multicolor_leds.devices[zone];
+ led_cdev = &multicolor_led_dev->led_cdev;
+ priv = &hp_multicolor_leds.priv[zone];
+
+ if (num_zones == 1)
+ led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
+ "hp::kbd_backlight");
+ else if (num_zones > 1)
+ led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
+ "hp::kbd_backlight_zone%d",
+ zone);
+
+ if (!led_cdev->name)
+ return -ENOMEM;
+ led_cdev->brightness = hp_kbd_backlight_is_on() ?
+ LED_FULL : LED_OFF;
+ led_cdev->max_brightness = LED_FULL;
+ led_cdev->brightness_set_blocking = hp_kbd_set_brightness;
+ led_cdev->flags = LED_CORE_SUSPENDRESUME |
+ LED_RETAIN_AT_SHUTDOWN |
+ LED_BRIGHT_HW_CHANGED;
+
+ mc_subled_info = devm_kzalloc(dev, sizeof(*mc_subled_info) * 3,
+ GFP_KERNEL);
+ if (!mc_subled_info)
+ return -ENOMEM;
+
+ mc_subled_info[0].color_index = LED_COLOR_ID_RED;
+ mc_subled_info[1].color_index = LED_COLOR_ID_GREEN;
+ mc_subled_info[2].color_index = LED_COLOR_ID_BLUE;
+
+ for (int i = 0; i < 3; i++) {
+ int off = HP_COLOR_TABLE_PADDING + zone * 3 + i;
+
+ mc_subled_info[i].channel = zone * 3 + i;
+ mc_subled_info[i].intensity = color_table[off];
+ mc_subled_info[i].brightness = LED_FULL;
+ }
+
+ multicolor_led_dev->subled_info = mc_subled_info;
+ multicolor_led_dev->num_colors = 3;
+
+ ret = devm_led_classdev_multicolor_register(dev, multicolor_led_dev);
+ if (ret) {
+ dev_err(dev, "Failed to register multicolor RGB backlight\n");
+ return ret;
+ }
+
+ /* Initialize private data */
+ priv->zone = zone;
+ priv->last_brightness = LED_FULL;
+ }
+ return 0;
+}
+
+static int __init hp_kbd_rgb_setup(void)
+{
+ u8 keyboard_type;
+ int ret;
+
+ ret = hp_wmi_perform_query(HPWMI_GET_KEYBOARD_TYPE_QUERY, HPWMI_GM, &keyboard_type,
+ sizeof(keyboard_type), sizeof(keyboard_type));
+ if (ret)
+ return ret;
+
+ switch (keyboard_type) {
+ case HP_KEYBOARD_TYPE_FOURZONE_WITH_NUMPAD:
+ case HP_KEYBOARD_TYPE_FOURZONE_WITHOUT_NUMPAD:
+ return hp_mc_leds_register(4);
+ case HP_KEYBOARD_TYPE_SINGLEZONE_WITH_NUMPAD:
+ case HP_KEYBOARD_TYPE_SINGLEZONE_WITHOUT_NUMPAD:
+ return hp_mc_leds_register(1);
+ default:
+ return 0;
+ }
+}
+
static int platform_profile_omen_get_ec(enum platform_profile_option *profile)
{
int tp;
@@ -2230,6 +2500,10 @@ static int __init hp_wmi_bios_setup(struct platform_device *device)

thermal_profile_setup(device);

+ err = hp_kbd_rgb_setup();
+ if (err)
+ dev_err(&device->dev, "Failed to initialize keyboard RGB\n");
+
return 0;
}

--
2.53.0