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X-CSE-ConnectionGUID: q5HqFuKMRJeS98m8RSieWQ== X-CSE-MsgGUID: VTl5yAmUSoqUd/J3NuBkcA== X-IronPort-AV: E=McAfee;i="6800,10657,11783"; a="79256476" X-IronPort-AV: E=Sophos;i="6.23,229,1770624000"; d="scan'208";a="79256476" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2026 07:14:24 -0700 X-CSE-ConnectionGUID: YBSXxnzmQzOw3GAhcaxZGg== X-CSE-MsgGUID: BZgcGZNcRgmzhZT50hN1sQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,229,1770624000"; d="scan'208";a="261203111" Received: from ijarvine-mobl1.ger.corp.intel.com (HELO localhost) ([10.245.245.28]) by smtpauth.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 May 2026 07:14:22 -0700 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 11 May 2026 17:14:18 +0300 (EEST) To: "Yo-Jung Leo Lin (AMD)" cc: Hans de Goede , "Mario Limonciello (AMD)" , LKML , platform-driver-x86@vger.kernel.org Subject: Re: [PATCH v3] platform/x86/amd: Introduce Halo Box RGB LED driver In-Reply-To: <20260508-halo-leds-v2-plus-v3-1-91df458966ea@amd.com> Message-ID: <4c416cce-dd01-9aa9-093a-8ec6bfe1b7b8@linux.intel.com> References: <20260508-halo-leds-v2-plus-v3-1-91df458966ea@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Fri, 8 May 2026, Yo-Jung Leo Lin (AMD) wrote: > The Halo Box features an RGB LED light bar that can be controlled > through WMI methods to display any color combination. > > The driver exposes the LED through the LED multicolor subsystem, > allowing userspace to control RGB values via sysfs: > /sys/class/leds/amd_halo:multicolor:status/multi_intensity > /sys/class/leds/amd_halo:multicolor:status/brightness > > Hardware interface: > - Three separate RGB channels (Red, Green, Blue) > - Each channel controlled via individual WMI method calls > - Value range: 0-100 (matching hardware range directly) > > Co-developed-by: Mario Limonciello (AMD) > Signed-off-by: Mario Limonciello (AMD) > Signed-off-by: Yo-Jung Leo Lin (AMD) > --- > v2 -> v3: > - Re-introduce OF/OFF method: implement them with wmidev_invoke_method > - Explicitly call the ON method on brightness_set callback for > brightness != 0; call the OFF method when brightness == 0 > - Turn off light bar if TURN_ON/SET_LIGHTBAR can't function normally > - Replace get_unaligned_le64 with casting and le16_to_cpu() > - Add an inline function (wmi_status_to_err) to convert WMI return > values to errno > - Use amd_halo_wmi_set_channel in probe to set default color > - Use devm_mutex_init() instead > - Remove unused includes > - Link to v2: https://lore.kernel.org/r/20260504-halo-leds-v2-plus-v2-1-af027727605b@amd.com > > v1 -> v2: > - Fix Kconfig dependencies > - Remove amd_halo_wmi_turn_off(). Handle the case where brightness=0 with the > same logic where brightness != 0 > - Remove the brightness_get callback, because currently there isn't a > well-defined global bightness in hardware. Note that the sysfs brightness > stil works. It just caches the value last set. > - Convert to wmidev_invoke_method() > - Convert to ARRAY_SIZE() > - Convert some macros to enum > - Convert to devm_led_classdev_multicolor_register_ext() > - Rename sysfs path to amd_halo:multicolor:status > - Fold default LED colors setting in probe, before registration > - Add no_singleton option > - Make default RGB values into macros and adjust their values > --- > MAINTAINERS | 7 + > drivers/platform/x86/amd/Kconfig | 11 ++ > drivers/platform/x86/amd/Makefile | 1 + > drivers/platform/x86/amd/amd_halo_led.c | 312 ++++++++++++++++++++++++++++++++ > 4 files changed, 331 insertions(+) > > diff --git a/MAINTAINERS b/MAINTAINERS > index c871acf2179c..464bd4d16461 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -1124,6 +1124,13 @@ F: drivers/char/hw_random/geode-rng.c > F: drivers/crypto/geode* > F: drivers/video/fbdev/geode/ > > +AMD HALO BOX RGB LED DRIVER > +M: Mario Limonciello (AMD) > +R: Yo-Jung Leo Lin (AMD) > +L: platform-driver-x86@vger.kernel.org > +S: Supported > +F: drivers/platform/x86/amd/amd_halo_led.c > + > AMD HSMP DRIVER > M: Naveen Krishna Chatradhi > R: Carlos Bilbao > diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig > index b813f9265368..a1a74ef6c859 100644 > --- a/drivers/platform/x86/amd/Kconfig > +++ b/drivers/platform/x86/amd/Kconfig > @@ -34,6 +34,17 @@ config AMD_WBRF > This mechanism will only be activated on platforms that advertise a > need for it. > > +config AMD_HALO_LED > + tristate "AMD Halo Box RGB LED Driver" > + depends on ACPI_WMI && LEDS_CLASS_MULTICOLOR > + help > + This driver provides RGB LED control for AMD Halo Box devices > + through the LED multicolor subsystem. The Halo Box light bar can > + be controlled via sysfs to display any RGB color combination. > + > + To compile this driver as a module, choose M here: the module > + will be called amd_halo_led. > + > config AMD_ISP_PLATFORM > tristate "AMD ISP4 platform driver" > depends on I2C && X86_64 && ACPI > diff --git a/drivers/platform/x86/amd/Makefile b/drivers/platform/x86/amd/Makefile > index f6ff0c837f34..2f467dbbfc8a 100644 > --- a/drivers/platform/x86/amd/Makefile > +++ b/drivers/platform/x86/amd/Makefile > @@ -10,5 +10,6 @@ obj-$(CONFIG_AMD_PMC) += pmc/ > obj-$(CONFIG_AMD_HSMP) += hsmp/ > obj-$(CONFIG_AMD_PMF) += pmf/ > obj-$(CONFIG_AMD_WBRF) += wbrf.o > +obj-$(CONFIG_AMD_HALO_LED) += amd_halo_led.o > obj-$(CONFIG_AMD_ISP_PLATFORM) += amd_isp4.o > obj-$(CONFIG_AMD_HFI) += hfi/ > diff --git a/drivers/platform/x86/amd/amd_halo_led.c b/drivers/platform/x86/amd/amd_halo_led.c > new file mode 100644 > index 000000000000..632ccdf07ffe > --- /dev/null > +++ b/drivers/platform/x86/amd/amd_halo_led.c > @@ -0,0 +1,312 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * AMD Halo Box RGB LED Driver > + * > + * Copyright (C) 2026 Advanced Micro Devices, Inc. > + * > + * This driver provides RGB LED control for AMD Halo Box devices through > + * the LED multicolor subsystem. The Halo Box light bar can be controlled > + * via sysfs to display any RGB color combination. > + */ > + > +#include > +#include > +#include > +#include > +#include > + > +#define AMD_HALO_GUID "081E747B-E028-4232-AF24-EAAEAB2B1E86" > + > +/* WMI method IDs from MOF */ > +enum { > + AMD_HALO_WMI_GET_LIGHTBAR = 0x01, > + AMD_HALO_WMI_SET_LIGHTBAR, > + AMD_HALO_WMI_TURN_ON, > + AMD_HALO_WMI_TURN_OFF > +}; > + > +/* Channel selectors for Arg0 */ > +enum { > + AMD_HALO_CHANNEL_RED = 0x01, > + AMD_HALO_CHANNEL_GREEN, > + AMD_HALO_CHANNEL_BLUE > +}; > + > +/* Status codes from spec */ > +#define AMD_HALO_STATUS_SUCCESS 0x0000 > +#define AMD_HALO_STATUS_INVALID_PARAM 0xFFFD > + > +/* Brightness uses 0-100 range */ > +#define AMD_HALO_MAX_HW_BRIGHTNESS 100 > + > +/* Default RGB brightness */ > +#define AMD_HALO_DEFAULT_RED 50 > +#define AMD_HALO_DEFAULT_GREEN 30 > +#define AMD_HALO_DEFAULT_BLUE 30 > + > +/** > + * struct amd_halo_led_data - Driver private data > + * @wdev: WMI device pointer > + * @led_mc: LED multicolor class device > + * @subled_info: RGB channel information > + * @lock: Mutex to protect WMI calls > + */ > +struct amd_halo_led_data { > + struct wmi_device *wdev; > + struct led_classdev_mc led_mc; > + struct mc_subled subled_info[3]; > + struct mutex lock; /* Protects WMI method calls */ > +}; > + > +struct amd_halo_wmi_args { > + u32 arg0; > + u32 arg1; > +}; > + > +static inline int wmi_status_to_err(u16 status) > +{ > + switch (status) { > + case AMD_HALO_STATUS_SUCCESS: > + return 0; > + case AMD_HALO_STATUS_INVALID_PARAM: > + return -EINVAL; > + default: > + return -EIO; > + } > +} > + > +static int __amd_halo_wmi_call(struct wmi_device *wdev, > + u32 method_id, > + u32 arg0, > + u32 arg1) Fits to less lines. > +{ > + struct amd_halo_wmi_args args = { > + .arg0 = arg0, > + .arg1 = arg1, > + }; > + struct wmi_buffer input = { > + .length = sizeof(args), > + .data = &args, > + }; > + struct wmi_buffer output = { 0 }; = {} is enough to initialize to default values. > + u16 result_status; > + int ret; > + > + ret = wmidev_invoke_method(wdev, 0, method_id, > + &input, &output, sizeof(result_status)); > + if (ret) > + return ret; > + > + /* Return buffer per spec: Bytes[0:1] = Status (little-endian) */ > + result_status = le16_to_cpu(*(__le16 *)output.data); Add include for le16_to_cpu() > + ret = wmi_status_to_err(result_status); > + > + kfree(output.data); Add include for kfree() > + return ret; > +} > + > +/** > + * amd_halo_wmi_turn_on - Turn on all LED channels > + * @wdev: WMI device pointer > + * > + * Return: 0 on success, negative error code on failure > + */ > +static int amd_halo_wmi_turn_on(struct wmi_device *wdev) > +{ > + return __amd_halo_wmi_call(wdev, AMD_HALO_WMI_TURN_ON, 0, 0); > +} > + > +/** > + * amd_halo_wmi_turn_off - Turn off all LED channels > + * @wdev: WMI device pointer > + * > + * Return: 0 on success, negative error code on failure > + */ > +static int amd_halo_wmi_turn_off(struct wmi_device *wdev) > +{ > + return __amd_halo_wmi_call(wdev, AMD_HALO_WMI_TURN_OFF, 0, 0); > +} > + > +/** > + * amd_halo_wmi_set_channel - Set a single RGB channel value > + * @wdev: WMI device pointer > + * @channel: Channel selector (1=Red, 2=Green, 3=Blue) > + * @brightness: brightness to set (0-100) > + * > + * Return: 0 on success, negative error code on failure > + */ > +static int amd_halo_wmi_set_channel(struct wmi_device *wdev, u32 channel, > + u32 brightness) > +{ > + if (channel < AMD_HALO_CHANNEL_RED || > + channel > AMD_HALO_CHANNEL_BLUE || > + brightness > AMD_HALO_MAX_HW_BRIGHTNESS) > + return -EINVAL; > + > + return __amd_halo_wmi_call(wdev, AMD_HALO_WMI_SET_LIGHTBAR, > + channel, brightness); > +} > + > +/** > + * amd_halo_brightness_set - Set LED brightness and color > + * @cdev: LED class device > + * @brightness: Brightness value > + * > + * Return: 0 on success, negative error code on failure > + */ > +static int amd_halo_brightness_set(struct led_classdev *cdev, > + enum led_brightness brightness) > +{ > + struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev); > + struct amd_halo_led_data *data = container_of(mc_cdev, > + struct amd_halo_led_data, > + led_mc); Alignment off by 1. > + u32 red_hw, green_hw, blue_hw; > + int ret; > + > + guard(mutex)(&data->lock); > + > + led_mc_calc_color_components(mc_cdev, brightness); > + > + if (brightness == 0) > + return amd_halo_wmi_turn_off(data->wdev); > + > + red_hw = mc_cdev->subled_info[0].brightness; > + green_hw = mc_cdev->subled_info[1].brightness; > + blue_hw = mc_cdev->subled_info[2].brightness; > + > + ret = amd_halo_wmi_turn_on(data->wdev); > + if (ret) > + goto out; > + > + ret = amd_halo_wmi_set_channel(data->wdev, AMD_HALO_CHANNEL_RED, > + red_hw); I suggest putting all these 3 to one line (instead of 2 lines each). > + if (ret) > + goto out; > + > + ret = amd_halo_wmi_set_channel(data->wdev, AMD_HALO_CHANNEL_GREEN, > + green_hw); > + if (ret) > + goto out; > + > + ret = amd_halo_wmi_set_channel(data->wdev, AMD_HALO_CHANNEL_BLUE, > + blue_hw); > + if (ret) > + goto out; > + > + return 0; > + > +out: > + /* > + * Consider the light bar non-functional if TURN_ON or SET_LIGHTBAR failed. > + * Attempt to turn the LED off completely as clean-up. > + */ > + if (amd_halo_wmi_turn_off(data->wdev)) > + dev_warn_ratelimited(&data->wdev->dev, "Failed to turn LED off on cleanup\n"); > + > + return ret; > +} > + > +/** > + * amd_halo_probe - Driver probe function > + * @wdev: WMI device > + * @context: Context data (unused) > + * > + * Return: 0 on success, negative error code on failure > + */ > +static int amd_halo_probe(struct wmi_device *wdev, const void *context) > +{ > + struct led_init_data led_init_data = { > + .devicename = "amd_halo", > + .default_label = "multicolor:" LED_FUNCTION_STATUS, > + .devname_mandatory = true Add the trailing comma to any non-terminating entry. -- i. > + }; > + struct amd_halo_led_data *data; > + int ret; > + > + data = devm_kzalloc(&wdev->dev, sizeof(*data), GFP_KERNEL); > + if (!data) > + return -ENOMEM; > + > + ret = devm_mutex_init(&wdev->dev, &data->lock); > + if (ret) > + return ret; > + > + data->wdev = wdev; > + dev_set_drvdata(&wdev->dev, data); > + > + data->subled_info[0].color_index = LED_COLOR_ID_RED; > + data->subled_info[1].color_index = LED_COLOR_ID_GREEN; > + data->subled_info[2].color_index = LED_COLOR_ID_BLUE; > + data->subled_info[0].intensity = AMD_HALO_DEFAULT_RED; > + data->subled_info[1].intensity = AMD_HALO_DEFAULT_GREEN; > + data->subled_info[2].intensity = AMD_HALO_DEFAULT_BLUE; > + > + data->led_mc.led_cdev.brightness = AMD_HALO_MAX_HW_BRIGHTNESS; > + data->led_mc.led_cdev.max_brightness = AMD_HALO_MAX_HW_BRIGHTNESS; > + data->led_mc.led_cdev.brightness_set_blocking = amd_halo_brightness_set; > + data->led_mc.led_cdev.flags = LED_CORE_SUSPENDRESUME | LED_RETAIN_AT_SHUTDOWN; > + data->led_mc.num_colors = ARRAY_SIZE(data->subled_info); > + data->led_mc.subled_info = data->subled_info; > + > + ret = amd_halo_wmi_turn_on(wdev); > + if (ret) > + goto out; > + > + ret = amd_halo_wmi_set_channel(wdev, AMD_HALO_CHANNEL_RED, > + AMD_HALO_DEFAULT_RED); > + if (ret) > + goto out; > + > + ret = amd_halo_wmi_set_channel(wdev, AMD_HALO_CHANNEL_GREEN, > + AMD_HALO_DEFAULT_GREEN); > + if (ret) > + goto out; > + > + ret = amd_halo_wmi_set_channel(wdev, AMD_HALO_CHANNEL_BLUE, > + AMD_HALO_DEFAULT_BLUE); > + if (ret) > + goto out; > + > + ret = devm_led_classdev_multicolor_register_ext(&wdev->dev, &data->led_mc, > + &led_init_data); > + if (ret) > + return dev_err_probe(&wdev->dev, ret, > + "Failed to register multicolor LED\n"); > + return 0; > + > +out: > + /* > + * Attempt to turn LED off as a cleanup if either TURN_ON or SET_LIGHTBAR > + * fails. For probe failure due to non-WMI errors, keep the LED in the > + * default color. > + */ > + dev_warn(&data->wdev->dev, "Light bar non-functional, turning it off\n"); > + > + if (amd_halo_wmi_turn_off(data->wdev)) > + dev_warn(&data->wdev->dev, "Failed to turn LED off on cleanup\n"); > + > + return dev_err_probe(&wdev->dev, ret, "WMI call failed during probe!\n"); > +} > + > +static const struct wmi_device_id amd_halo_id_table[] = { > + { .guid_string = AMD_HALO_GUID }, > + { } > +}; > +MODULE_DEVICE_TABLE(wmi, amd_halo_id_table); > + > +static struct wmi_driver amd_halo_driver = { > + .driver = { > + .name = "amd_halo_led", > + }, > + .id_table = amd_halo_id_table, > + .probe = amd_halo_probe, > + .no_singleton = true, > +}; > + > +module_wmi_driver(amd_halo_driver); > + > +MODULE_AUTHOR("Mario Limonciello (AMD) "); > +MODULE_AUTHOR("Yo-Jung Leo Lin (AMD) "); > +MODULE_DESCRIPTION("AMD Halo Box RGB LED Control Driver"); > +MODULE_LICENSE("GPL"); > > --- > base-commit: 39704f00f747aba3144289870b5fd8ac230a9aaf > change-id: 20260429-halo-leds-v2-plus-722c8083afe8 > > Best regards, >