Re: [PATCH v10] platform/x86: hp-wmi: Add multicolor LED support for HP keyboard backlight

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Sun, 14 Jun 2026, Коненко Андрей Викторович wrote:

> 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: Konenko Andrey Viktorovich <admin@aquinas.su>
> 
> ---
> Changes since v9:
>  - Fixed corrupted long lines
>  - Fixed changelog
> 
> Changes since v8:
>  - No changes (It was mistake to resend email without any fix)
> 
> Changes since v7:
>  - The LED class device names changed to be consistent with the documentation.
> 
> Changes since v6:
>  - The LED class device names have been made more consistent with the 
> documentation, in accordance with patch https://lore.kernel.org/linux-leds/
> 20260504145434.12746-1-johannes.goede@oss.qualcomm.com/
> underscores have been replaced with dashes where indicated.
> 
> Changes since v5:
>  - LED class device names changed from a number to using a descriptive name 
> for each zone.
> 
> v4: https://lore.kernel.org/all/20260303084022.7223-3-edip@medip.dev/
> 
> Changes since v4:
>  - Fix circular dependencies
> 
> Changes since v3:
>  - Merge the changes into a single commit
> 
> Changes since v1:
>  - Fix mentioned style errors
>  - Add Kconfig dependencies
> 
> 
> ---
> 
> diff --git a/drivers/platform/x86/hp/Kconfig b/drivers/platform/x86/hp/Kconfig
> index dd51491b9bcd..2a1841cbec76 100644
> --- a/drivers/platform/x86/hp/Kconfig
> +++ b/drivers/platform/x86/hp/Kconfig
> @@ -45,6 +45,8 @@ config HP_WMI
>         select INPUT_SPARSEKMAP
>         select ACPI_PLATFORM_PROFILE
>         select HWMON
> +       select LEDS_CLASS
> +       select LEDS_CLASS_MULTICOLOR
>         help
>           Say Y here if you want to support WMI-based hotkeys on HP laptops and
>           to read data from WMI such as docking or ambient light sensor state.
> diff --git a/drivers/platform/x86/hp/hp-wmi.c b/drivers/platform/x86/hp/hp-wmi.c
> index d1cc6e7d176c..19da18f68337 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>
> @@ -57,6 +60,7 @@ enum hp_ec_offsets {
>  
>  #define HP_FAN_SPEED_AUTOMATIC  0x00
>  #define HP_POWER_LIMIT_DEFAULT  0x00
> +#define HP_COLOR_TABLE_PADDING  25
>  #define HP_POWER_LIMIT_NO_CHANGE 0xFF
>  
>  #define zero_if_sup(tmp) (zero_insize_support?0:sizeof(tmp)) // use when zero insize is required
> @@ -97,6 +101,14 @@ 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;
> @@ -338,16 +350,27 @@ 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 {
> @@ -355,6 +378,24 @@ enum hp_wmi_hardware_mask {
>         HPWMI_TABLET_MASK       = 0x04,
>  };
>  
> +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];
> +};
> +
> +/* zone naming for 4-zone keyboards (HP Omen) */
> +static const char *const hp_zone_names_4[] = {
> +       [0] = "zoned_backlight-right",
> +       [1] = "zoned_backlight-center",
> +       [2] = "zoned_backlight-left",
> +       [3] = "zoned_backlight-wasd",
> +};
> +
>  struct bios_return {
>         u32 sigpass;
>         u32 return_code;
> @@ -435,6 +476,7 @@ 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;
> @@ -1122,6 +1164,8 @@ 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;
> @@ -1222,6 +1266,7 @@ 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;
> @@ -1484,6 +1529,241 @@ 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) {

Instead of literals, can these two be named with defines?

It would also seem like switch/case is more appropriate construct here 
that if/else forest.

> +                       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 == 4 && zone < ARRAY_SIZE(hp_zone_names_4))
> +                       led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
> +                                                       "hp::kbd_%s",
> +                                                       hp_zone_names_4[zone]);
> +               else if (num_zones > 1)
> +                       led_cdev->name = devm_kasprintf(dev, GFP_KERNEL,
> +                                                       "hp::kbd_zoned_backlight-%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;

You seem to have many literal 3 in this driver, and it would be easier to 
find relevant ones for each case if you replace them with define(s).

This seems fine otherwise, AFAICT.

> +               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;
> @@ -2285,7 +2565,9 @@ static int __init hp_wmi_bios_setup(struct platform_device *device)
>                 return err;
>  
>         thermal_profile_setup(device);
> -
> +       err = hp_kbd_rgb_setup();
> +       if (err)
> +               dev_err(&device->dev, "Failed to initialize keyboard RGB\n");
>         return 0;
>  }
>  
> 

-- 
 i.