RE: [PATCH v8 1/2] platform/x86: dell-privacy: Add support for Dell hardware privacy

["Yuan, Perry" <Perry.Yuan@dell.com>]

Hi Hans.

> -----Original Message-----
> From: Hans de Goede <hdegoede@redhat.com>
> Sent: 2021年5月25日 20:42
> To: Yuan, Perry; pobrn@protonmail.com; pierre-
> louis.bossart@linux.intel.com; oder_chiou@realtek.com; perex@perex.cz;
> tiwai@suse.com; mgross@linux.intel.com
> Cc: lgirdwood@gmail.com; broonie@kernel.org; alsa-devel@alsa-project.org;
> linux-kernel@vger.kernel.org; platform-driver-x86@vger.kernel.org;
> mario.limonciello@outlook.com; Dell Client Kernel
> Subject: Re: [PATCH v8 1/2] platform/x86: dell-privacy: Add support for Dell
> hardware privacy
> 
> 
> [EXTERNAL EMAIL]
> 
> Hi Perry,
> 
> On 5/20/21 2:16 PM, Hans de Goede wrote:
> > Hi Perry,
> >
> > On 5/18/21 3:02 PM, Hans de Goede wrote:
> >> Hi Perry,
> >>
> >> On 5/6/21 1:56 PM, Perry Yuan wrote:
> >>> From: Perry Yuan <perry_yuan@dell.com>
> >>>
> >>> add support for Dell privacy driver for the Dell units equipped
> >>> hardware privacy design, which protect users privacy of audio and
> >>> camera from hardware level. Once the audio or camera privacy mode
> >>> activated, any applications will not get any audio or video stream
> >>> when user pressed ctrl+F4 hotkey, audio privacy mode will be
> >>> enabled, micmute led will be also changed accordingly The micmute
> >>> led is fully controlled by hardware & EC(embedded controller) and
> >>> camera mute hotkey is Ctrl+F9. Currently design only emits
> >>> SW_CAMERA_LENS_COVER event while the camera lens shutter will be
> >>> changed by EC & HW(hardware) control
> >>>
> >>> *The flow is like this:
> >>> 1) User presses key. HW does stuff with this key (timeout timer is
> >>> started)
> >>> 2) WMI event is emitted from BIOS to kernel
> >>> 3) WMI event is received by dell-privacy
> >>> 4) KEY_MICMUTE emitted from dell-privacy
> >>> 5) Userland picks up key and modifies kcontrol for SW mute
> >>> 6) Codec kernel driver catches and calls ledtrig_audio_set, like this:
> >>>    ledtrig_audio_set(LED_AUDIO_MICMUTE, rt715->micmute_led ?
> LED_ON
> >>> :LED_OFF);
> >>> 7) If "LED" is set to on dell-privacy notifies EC, and timeout is cancelled,
> >>>    HW mic mute activated. If EC not notified, HW mic mute will also be
> >>>    activated when timeout used up, it is just later than active ack
> >>>
> >>> Signed-off-by: Perry Yuan <perry_yuan@dell.com>
> >>>
> >>> ---
> >>> v7 -> v8:
> >>> * addressed feedback from Hans
> >>> * use sysfs_emit_at in the sysfs attributes
> >>> * Update Kconfig
> >>> * improve led_classdev_unregister logic in dell-laptop
> >>
> >> Thank you, this version looks good to me, with the exception of then
> >> issue with e.g. dell-wmi being builtin vs dell-privacy being a module
> >> which will lead to the kernel not compiling.
> >>
> >> I've implemented the fix which I described/suggested in the
> >> discussion about this in the v7 thread.
> >>
> >> I've attached 4 patches:
> >>
> >> [PATCH 1/4] platform/x86: dell-wmi: Rename dell-wmi.c to
> >> dell-wmi-base.c -This is a preparation patch for the Makefile +
> >> Kconfig changes suggested  in the v7 email thread [PATCH 2/4]
> >> platform/x86: dell-privacy: Add support for Dell hardware privacy
> >> -This is your v8 patch (without any changes) [PATCH 3/4] FIXUP
> >> platform/x86: dell-privacy: Add support for Dell hardware privacy
> >> -This implements the discussed Makefile + Kconfig changes, as well as
> >> renaming dell-privacy-wmi.? to dell-wmi-privacy.? to because the
> >> privacy  code now is a part of the dell-wmi module [PATCH 4/4] FIXUP
> >> platform/x86: dell-privacy: Add support for Dell hardware privacy
> >> -Some small changes from reviewing v8
> >>
> >> I've also pushed these 4 to my review-hans branch. Perry, if you can
> >> let me know if the suggested changes in the 2 FIXUP patches are ok
> >> with you then I'll squash them into the 2/4 patch (so that only 1/2
> >> and 2/2 remain) and then push this to for-next.
> >
> > Perry, can you please let me know if you are ok with the changes from
> > the 2 FIXME follow up patches which I attached to my previous email
> > and which are also in the pdx86/review-hans branch ?
> >
> > I would like to ge this merged and I'm waiting for your ack for this.
> 
> Ping? Can I get a reaction to this please. If you are busy with some other things
> and need some time, that is fine, but please let me know.
> 
> Regards,
> 
> Hans

Thanks a lot for your support.
The patches looks better.
Please help to get them merged in your review branch.
Acked.
> 
> 
> 
> 
> 
> 
> >>> v6 -> v7:
> >>> * addressed feedback from Hans
> >>> * addressed feedback from Pierre
> >>> * optimize some debug format with dev_dbg()
> >>> v5 -> v6:
> >>> * remove platform driver,combined privacy acpi driver into single wmi
> >>>   driver file
> >>> * optimize sysfs interface with string added to be more clearly
> >>> reading
> >>> * remove unused function and clear header file
> >>> v4 -> v5:
> >>> * addressed feedback from Randy Dunlap
> >>> * addressed feedback from Pierre-Louis Bossart
> >>> * rebase to latest 5.12 rc4 upstream kernel
> >>> * fix some space alignment problem
> >>> v3 -> v4:
> >>> * fix format for Kconfig
> >>> * add sysfs document
> >>> * add flow comments to the privacy wmi/acpi driver
> >>> * addressed feedback from Barnabás Pőcze[Thanks very much]
> >>> * export privacy_valid to make the global state simpler to query
> >>> * fix one issue which will block the dell-laptop driver to load when
> >>>   privacy driver invalid
> >>> * addressed feedback from Pierre-Louis Bossart,remove the EC ID
> >>> match
> >>> v2 -> v3:
> >>> * add sysfs attributes doc
> >>> v1 -> v2:
> >>> * query EC handle from EC driver directly.
> >>> * fix some code style.
> >>> * add KEY_END to keymap array.
> >>> * clean platform device when cleanup called
> >>> * use hexadecimal format for log print in dev_dbg
> >>> * remove __set_bit for the report keys from probe.
> >>> * fix keymap leak
> >>> * add err_free_keymap in dell_privacy_wmi_probe
> >>> * wmi driver will be unregistered if privacy_acpi_init() fails
> >>> * add sysfs attribute files for user space query.
> >>> * add leds micmute driver to privacy acpi
> >>> * add more design info the commit info
> >>> ---
> >>> ---
> >>>  .../testing/sysfs-platform-dell-privacy-wmi   |  55 +++
> >>>  drivers/platform/x86/dell/Kconfig             |  14 +
> >>>  drivers/platform/x86/dell/Makefile            |   1 +
> >>>  drivers/platform/x86/dell/dell-laptop.c       |  13 +-
> >>>  drivers/platform/x86/dell/dell-privacy-wmi.c  | 394
> >>> ++++++++++++++++++  drivers/platform/x86/dell/dell-privacy-wmi.h  |  25
> ++
> >>>  drivers/platform/x86/dell/dell-wmi.c          |   9 +-
> >>>  7 files changed, 507 insertions(+), 4 deletions(-)  create mode
> >>> 100644 Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi
> >>>  create mode 100644 drivers/platform/x86/dell/dell-privacy-wmi.c
> >>>  create mode 100644 drivers/platform/x86/dell/dell-privacy-wmi.h
> >>>
> >>> diff --git
> >>> a/Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi
> >>> b/Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi
> >>> new file mode 100644
> >>> index 000000000000..7f9e18705861
> >>> --- /dev/null
> >>> +++ b/Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi
> >>> @@ -0,0 +1,55 @@
> >>> +What:		/sys/bus/wmi/devices/6932965F-1671-4CEB-B988-
> D3AB0A901919/dell_privacy_supported_type
> >>> +Date:		Apr 2021
> >>> +KernelVersion:	5.13
> >>> +Contact:	"perry.yuan@dell.com>"
> >>> +Description:
> >>> +		Display which dell hardware level privacy devices are
> supported
> >>> +		“Dell Privacy” is a set of HW, FW, and SW features to enhance
> >>> +		Dell’s commitment to platform privacy for MIC, Camera, and
> >>> +		ePrivacy screens.
> >>> +		The supported hardware privacy devices are:
> >>> +Attributes:
> >>> +		Microphone Mute:
> >>> +				Identifies the local microphone can be muted
> by hardware, no applications
> >>> +				is available to capture system mic sound
> >>> +
> >>> +		Camera Shutter:
> >>> +				Identifies camera shutter controlled by
> hardware, which is a micromechanical
> >>> +				shutter assembly that is built onto the camera
> module to block capturing images
> >>> +				from outside the laptop
> >>> +
> >>> +		supported:
> >>> +				The privacy device is supported by this system
> >>> +
> >>> +		unsupported:
> >>> +				The privacy device is not supported on this
> system
> >>> +
> >>> +		For example to check which privacy devices are supported:
> >>> +
> >>> +		# cat /sys/bus/wmi/drivers/dell-privacy/6932965F-1671-
> 4CEB-B988-D3AB0A901919/dell_privacy_supported_type
> >>> +		[Microphone Mute] [supported]
> >>> +		[Camera Shutter] [supported]
> >>> +		[ePrivacy Screen] [unsupported]
> >>> +
> >>> +What:		/sys/bus/wmi/devices/6932965F-1671-4CEB-B988-
> D3AB0A901919/dell_privacy_current_state
> >>> +Date:		Apr 2021
> >>> +KernelVersion:	5.13
> >>> +Contact:	"perry.yuan@dell.com>"
> >>> +Description:
> >>> +		Allow user space to check current dell privacy device state.
> >>> +		Describes the Device State class exposed by BIOS which can
> be
> >>> +		consumed by various applications interested in knowing the
> Privacy
> >>> +		feature capabilities
> >>> +Attributes:
> >>> +		muted:
> >>> +			Identifies the privacy device is turned off and cannot
> send
> >>> +stream to OS applications
> >>> +
> >>> +		unmuted:
> >>> +			Identifies the privacy device is turned on ,audio or
> camera driver can get
> >>> +			stream from mic and camera module to OS
> applications
> >>> +
> >>> +		For example to check all supported current privacy device
> states:
> >>> +
> >>> +		# cat /sys/bus/wmi/drivers/dell-privacy/6932965F-1671-
> 4CEB-B988-D3AB0A901919/dell_privacy_current_state
> >>> +		[Microphone] [unmuted]
> >>> +		[Camera Shutter] [unmuted]
> >>> diff --git a/drivers/platform/x86/dell/Kconfig
> >>> b/drivers/platform/x86/dell/Kconfig
> >>> index e0a55337f51a..be570ccbbce0 100644
> >>> --- a/drivers/platform/x86/dell/Kconfig
> >>> +++ b/drivers/platform/x86/dell/Kconfig
> >>> @@ -204,4 +204,18 @@ config DELL_WMI_SYSMAN
> >>>  	  To compile this driver as a module, choose M here: the module will
> >>>  	  be called dell-wmi-sysman.
> >>>
> >>> +config DELL_PRIVACY
> >>> +	tristate "Dell Hardware Privacy Support"
> >>> +	depends on ACPI
> >>> +	depends on ACPI_WMI
> >>> +	depends on INPUT
> >>> +	depends on DELL_LAPTOP
> >>> +	depends on LEDS_TRIGGER_AUDIO
> >>> +	depends on DELL_WMI
> >>> +	help
> >>> +	  This driver provides integration with the "Dell Hardware Privacy"
> feature
> >>> +	  of Dell laptops.
> >>> +
> >>> +	  To compile this driver as a module, choose M here: the module will
> >>> +	  be called dell_privacy.
> >>>  endif # X86_PLATFORM_DRIVERS_DELL
> >>> diff --git a/drivers/platform/x86/dell/Makefile
> >>> b/drivers/platform/x86/dell/Makefile
> >>> index d720a3e42ae3..7da0c33dfcca 100644
> >>> --- a/drivers/platform/x86/dell/Makefile
> >>> +++ b/drivers/platform/x86/dell/Makefile
> >>> @@ -19,3 +19,4 @@ obj-$(CONFIG_DELL_WMI_AIO)		+=
> dell-wmi-aio.o
> >>>  obj-$(CONFIG_DELL_WMI_DESCRIPTOR)	+= dell-wmi-descriptor.o
> >>>  obj-$(CONFIG_DELL_WMI_LED)		+= dell-wmi-led.o
> >>>  obj-$(CONFIG_DELL_WMI_SYSMAN)		+= dell-wmi-sysman/
> >>> +obj-$(CONFIG_DELL_PRIVACY)              += dell-privacy-wmi.o
> >>> diff --git a/drivers/platform/x86/dell/dell-laptop.c
> >>> b/drivers/platform/x86/dell/dell-laptop.c
> >>> index 70edc5bb3a14..529547fb0cb1 100644
> >>> --- a/drivers/platform/x86/dell/dell-laptop.c
> >>> +++ b/drivers/platform/x86/dell/dell-laptop.c
> >>> @@ -31,6 +31,8 @@
> >>>  #include "dell-rbtn.h"
> >>>  #include "dell-smbios.h"
> >>>
> >>> +#include "dell-privacy-wmi.h"
> >>> +
> >>>  struct quirk_entry {
> >>>  	bool touchpad_led;
> >>>  	bool kbd_led_not_present;
> >>> @@ -90,6 +92,7 @@ static struct rfkill *wifi_rfkill;  static struct
> >>> rfkill *bluetooth_rfkill;  static struct rfkill *wwan_rfkill;
> >>> static bool force_rfkill;
> >>> +static bool micmute_led_registered;
> >>>
> >>>  module_param(force_rfkill, bool, 0444);
> >>> MODULE_PARM_DESC(force_rfkill, "enable rfkill on non whitelisted
> >>> models"); @@ -2205,11 +2208,13 @@ static int __init dell_init(void)
> >>>  	dell_laptop_register_notifier(&dell_laptop_notifier);
> >>>
> >>>  	if (dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE) &&
> >>> -	    dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE)) {
> >>> +	    dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE) &&
> >>> +	    !dell_privacy_present()) {
> >>>  		micmute_led_cdev.brightness =
> ledtrig_audio_get(LED_AUDIO_MICMUTE);
> >>>  		ret = led_classdev_register(&platform_device->dev,
> &micmute_led_cdev);
> >>>  		if (ret < 0)
> >>>  			goto fail_led;
> >>> +		micmute_led_registered = true;
> >>>  	}
> >>>
> >>>  	if (acpi_video_get_backlight_type() != acpi_backlight_vendor) @@
> >>> -2257,7 +2262,8 @@ static int __init dell_init(void)
> >>>  fail_get_brightness:
> >>>  	backlight_device_unregister(dell_backlight_device);
> >>>  fail_backlight:
> >>> -	led_classdev_unregister(&micmute_led_cdev);
> >>> +	if (micmute_led_registered)
> >>> +		led_classdev_unregister(&micmute_led_cdev);
> >>>  fail_led:
> >>>  	dell_cleanup_rfkill();
> >>>  fail_rfkill:
> >>> @@ -2278,7 +2284,8 @@ static void __exit dell_exit(void)
> >>>  		touchpad_led_exit();
> >>>  	kbd_led_exit();
> >>>  	backlight_device_unregister(dell_backlight_device);
> >>> -	led_classdev_unregister(&micmute_led_cdev);
> >>> +	if (micmute_led_registered)
> >>> +		led_classdev_unregister(&micmute_led_cdev);
> >>>  	dell_cleanup_rfkill();
> >>>  	if (platform_device) {
> >>>  		platform_device_unregister(platform_device);
> >>> diff --git a/drivers/platform/x86/dell/dell-privacy-wmi.c
> >>> b/drivers/platform/x86/dell/dell-privacy-wmi.c
> >>> new file mode 100644
> >>> index 000000000000..a32d0fbd99da
> >>> --- /dev/null
> >>> +++ b/drivers/platform/x86/dell/dell-privacy-wmi.c
> >>> @@ -0,0 +1,394 @@
> >>> +// SPDX-License-Identifier: GPL-2.0-only
> >>> +/*
> >>> + * Dell privacy notification driver
> >>> + *
> >>> + * Copyright (C) 2021 Dell Inc. All Rights Reserved.
> >>> + */
> >>> +
> >>> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> >>> +
> >>> +#include <linux/acpi.h>
> >>> +#include <linux/bitops.h>
> >>> +#include <linux/input.h>
> >>> +#include <linux/input/sparse-keymap.h> #include <linux/list.h>
> >>> +#include <linux/leds.h> #include <linux/module.h> #include
> >>> +<linux/wmi.h>
> >>> +
> >>> +#include "dell-privacy-wmi.h"
> >>> +
> >>> +#define DELL_PRIVACY_GUID "6932965F-1671-4CEB-B988-
> D3AB0A901919"
> >>> +#define MICROPHONE_STATUS		BIT(0)
> >>> +#define CAMERA_STATUS		        BIT(1)
> >>> +#define DELL_PRIVACY_AUDIO_EVENT  0x1 #define
> >>> +DELL_PRIVACY_CAMERA_EVENT 0x2
> >>> +#define led_to_priv(c)       container_of(c, struct privacy_wmi_data, cdev)
> >>> +
> >>> +/*
> >>> + * The wmi_list is used to store the privacy_priv struct with mutex
> >>> +protecting  */ static LIST_HEAD(wmi_list); static
> >>> +DEFINE_MUTEX(list_mutex);
> >>> +
> >>> +struct privacy_wmi_data {
> >>> +	struct input_dev *input_dev;
> >>> +	struct wmi_device *wdev;
> >>> +	struct list_head list;
> >>> +	struct led_classdev cdev;
> >>> +	u32 features_present;
> >>> +	u32 last_status;
> >>> +};
> >>> +
> >>> +/* DELL Privacy Type */
> >>> +enum dell_hardware_privacy_type {
> >>> +	DELL_PRIVACY_TYPE_AUDIO = 0,
> >>> +	DELL_PRIVACY_TYPE_CAMERA,
> >>> +	DELL_PRIVACY_TYPE_SCREEN,
> >>> +	DELL_PRIVACY_TYPE_MAX,
> >>> +};
> >>> +
> >>> +static const char * const privacy_types[DELL_PRIVACY_TYPE_MAX] = {
> >>> +	[DELL_PRIVACY_TYPE_AUDIO] = "Microphone",
> >>> +	[DELL_PRIVACY_TYPE_CAMERA] = "Camera Shutter",
> >>> +	[DELL_PRIVACY_TYPE_SCREEN] = "ePrivacy Screen", };
> >>> +
> >>> +/*
> >>> + * Keymap for WMI privacy events of type 0x0012  */ static const
> >>> +struct key_entry dell_wmi_keymap_type_0012[] = {
> >>> +	/* privacy mic mute */
> >>> +	{ KE_KEY, 0x0001, { KEY_MICMUTE } },
> >>> +	/* privacy camera mute */
> >>> +	{ KE_SW,  0x0002, { SW_CAMERA_LENS_COVER } },
> >>> +	{ KE_END, 0},
> >>> +};
> >>> +
> >>> +/*
> >>> + * global privacy state for other modules to query if the privacy
> >>> +driver loaded successfully
> >>> + * or no privacy WMI device was detected at initial probe phase  */
> >>> +bool dell_privacy_present(void) {
> >>> +	struct privacy_wmi_data *priv;
> >>> +
> >>> +	mutex_lock(&list_mutex);
> >>> +	priv = list_first_entry_or_null(&wmi_list,
> >>> +			struct privacy_wmi_data,
> >>> +			list);
> >>> +	mutex_unlock(&list_mutex);
> >>> +
> >>> +	return priv && (priv->features_present &
> >>> +BIT(DELL_PRIVACY_TYPE_AUDIO)); }
> >>> +EXPORT_SYMBOL_GPL(dell_privacy_present);
> >>> +
> >>> +/*
> >>> + * The flow of privacy event:
> >>> + * 1) User presses key. HW does stuff with this key (timeout is
> >>> +started)
> >>> + * 2) WMI event is emitted from BIOS
> >>> + * 3) WMI event is received by dell-privacy
> >>> + * 4) KEY_MICMUTE emitted from dell-privacy
> >>> + * 5) Userland picks up key and modifies kcontrol for SW mute
> >>> + * 6) Codec kernel driver catches and calls ledtrig_audio_set defined by
> >>> + *    dell-privacy-acpi driver. Codec driver will call like this to switch
> micmute led state.
> >>> + *    ledtrig_audio_set(LED_AUDIO_MICMUTE, micmute_led ?
> LED_ON :LED_OFF);
> >>> + * 7) If "LED" is set to on dell-privacy notifies EC,and timeout is cancelled,
> >>> + *	HW mic mute activated.
> >>> + */
> >>> +bool dell_privacy_process_event(int type, int code, int status) {
> >>> +	struct privacy_wmi_data *priv;
> >>> +	const struct key_entry *key;
> >>> +	bool ret = false;
> >>> +
> >>> +	mutex_lock(&list_mutex);
> >>> +	priv = list_first_entry_or_null(&wmi_list,
> >>> +			struct privacy_wmi_data,
> >>> +			list);
> >>> +	if (!priv)
> >>> +		goto error;
> >>> +
> >>> +	key = sparse_keymap_entry_from_scancode(priv->input_dev, (type <<
> 16) | code);
> >>> +	if (!key) {
> >>> +		dev_warn(&priv->wdev->dev, "Unknown key with type
> 0x%04x and code 0x%04x pressed\n",
> >>> +			type, code);
> >>> +		goto error;
> >>> +	}
> >>> +	dev_dbg(&priv->wdev->dev, "Key with type 0x%04x and code 0x%04x
> >>> +pressed\n", type, code);
> >>> +
> >>> +	switch (code) {
> >>> +	case DELL_PRIVACY_AUDIO_EVENT: /* Mic mute */
> >>> +	case DELL_PRIVACY_CAMERA_EVENT: /* Camera mute */
> >>> +		priv->last_status = status;
> >>> +		sparse_keymap_report_entry(priv->input_dev, key, 1, true);
> >>> +		ret = true;
> >>> +		break;
> >>> +	default:
> >>> +		dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x
> 0x%04x\n", type, code);
> >>> +	}
> >>> +
> >>> +error:
> >>> +	mutex_unlock(&list_mutex);
> >>> +	return ret;
> >>> +}
> >>> +EXPORT_SYMBOL_GPL(dell_privacy_process_event);
> >>> +
> >>> +static ssize_t dell_privacy_supported_type_show(struct device *dev,
> >>> +					struct device_attribute *attr,
> >>> +					char *buf)
> >>> +{
> >>> +	struct privacy_wmi_data *priv = dev_get_drvdata(dev);
> >>> +	enum dell_hardware_privacy_type type;
> >>> +	u32 privacy_list;
> >>> +	int len = 0;
> >>> +
> >>> +	privacy_list = priv->features_present;
> >>> +	for (type = DELL_PRIVACY_TYPE_AUDIO; type <
> DELL_PRIVACY_TYPE_MAX; type++) {
> >>> +		if (privacy_list & BIT(type))
> >>> +			len += sysfs_emit_at(buf, len, "[%s] [supported]\n",
> privacy_types[type]);
> >>> +		else
> >>> +			len += sysfs_emit_at(buf, len, "[%s] [unsupported]\n",
> privacy_types[type]);
> >>> +	}
> >>> +
> >>> +	return len;
> >>> +}
> >>> +
> >>> +static ssize_t dell_privacy_current_state_show(struct device *dev,
> >>> +					struct device_attribute *attr,
> >>> +					char *buf)
> >>> +{
> >>> +	struct privacy_wmi_data *priv = dev_get_drvdata(dev);
> >>> +	u32 privacy_supported = priv->features_present;
> >>> +	enum dell_hardware_privacy_type type;
> >>> +	u32 privacy_state = priv->last_status;
> >>> +	int len = 0;
> >>> +
> >>> +	for (type = DELL_PRIVACY_TYPE_AUDIO; type <
> DELL_PRIVACY_TYPE_MAX; type++) {
> >>> +		if (privacy_supported & BIT(type)) {
> >>> +			if (privacy_state & BIT(type))
> >>> +				len += sysfs_emit_at(buf, len, "[%s]
> [unmuted]\n", privacy_types[type]);
> >>> +			else
> >>> +				len += sysfs_emit_at(buf, len, "[%s]
> [muted]\n", privacy_types[type]);
> >>> +		}
> >>> +	}
> >>> +
> >>> +	return len;
> >>> +}
> >>> +
> >>> +static DEVICE_ATTR_RO(dell_privacy_supported_type);
> >>> +static DEVICE_ATTR_RO(dell_privacy_current_state);
> >>> +
> >>> +static struct attribute *privacy_attributes[] = {
> >>> +	&dev_attr_dell_privacy_supported_type.attr,
> >>> +	&dev_attr_dell_privacy_current_state.attr,
> >>> +	NULL,
> >>> +};
> >>> +
> >>> +static const struct attribute_group privacy_attribute_group = {
> >>> +	.attrs = privacy_attributes
> >>> +};
> >>> +
> >>> +/*
> >>> + * Describes the Device State class exposed by BIOS which can be
> >>> +consumed by
> >>> + * various applications interested in knowing the Privacy feature
> capabilities.
> >>> + * class DeviceState
> >>> + * {
> >>> + *  [key, read] string InstanceName;
> >>> + *  [read] boolean ReadOnly;
> >>> + *
> >>> + *  [WmiDataId(1), read] uint32 DevicesSupported;
> >>> + *   0 - None; 0x1 - Microphone; 0x2 - Camera; 0x4 - ePrivacy  Screen
> >>> + *
> >>> + *  [WmiDataId(2), read] uint32 CurrentState;
> >>> + *   0 - Off; 1 - On; Bit0 - Microphone; Bit1 - Camera; Bit2 -
> ePrivacyScreen
> >>> + * };
> >>> + */
> >>> +static int get_current_status(struct wmi_device *wdev) {
> >>> +	struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
> >>> +	union acpi_object *obj_present;
> >>> +	u32 *buffer;
> >>> +	int ret = 0;
> >>> +
> >>> +	if (!priv) {
> >>> +		dev_err(&wdev->dev, "dell privacy priv is NULL\n");
> >>> +		return -EINVAL;
> >>> +	}
> >>> +	/* check privacy support features and device states */
> >>> +	obj_present = wmidev_block_query(wdev, 0);
> >>> +	if (!obj_present) {
> >>> +		dev_err(&wdev->dev, "failed to read Binary MOF\n");
> >>> +		return -EIO;
> >>> +	}
> >>> +
> >>> +	if (obj_present->type != ACPI_TYPE_BUFFER) {
> >>> +		dev_err(&wdev->dev, "Binary MOF is not a buffer!\n");
> >>> +		ret = -EIO;
> >>> +		goto obj_free;
> >>> +	}
> >>> +	/*  Although it's not technically a failure, this would lead to
> >>> +	 *  unexpected behavior
> >>> +	 */
> >>> +	if (obj_present->buffer.length != 8) {
> >>> +		dev_err(&wdev->dev, "Dell privacy buffer has unexpected
> length (%d)!\n",
> >>> +				obj_present->buffer.length);
> >>> +		ret = -EINVAL;
> >>> +		goto obj_free;
> >>> +	}
> >>> +	buffer = (u32 *)obj_present->buffer.pointer;
> >>> +	priv->features_present = buffer[0];
> >>> +	priv->last_status = buffer[1];
> >>> +
> >>> +obj_free:
> >>> +	kfree(obj_present);
> >>> +	return ret;
> >>> +}
> >>> +
> >>> +static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
> >>> +					enum led_brightness brightness) {
> >>> +	struct privacy_wmi_data *priv = led_to_priv(led_cdev);
> >>> +	static char *acpi_method = (char *)"ECAK";
> >>> +	acpi_status status;
> >>> +	acpi_handle handle;
> >>> +
> >>> +	handle = ec_get_handle();
> >>> +	if (!handle)
> >>> +		return -EIO;
> >>> +
> >>> +	if (!acpi_has_method(handle, acpi_method))
> >>> +		return -EIO;
> >>> +
> >>> +	status = acpi_evaluate_object(handle, acpi_method, NULL, NULL);
> >>> +	if (ACPI_FAILURE(status)) {
> >>> +		dev_err(&priv->wdev->dev, "Error setting privacy EC ack
> value: %s\n",
> >>> +				acpi_format_exception(status));
> >>> +		return -EIO;
> >>> +	}
> >>> +
> >>> +	return 0;
> >>> +}
> >>> +
> >>> +/*
> >>> + * Pressing the mute key activates a time delayed circuit to
> >>> +physically cut
> >>> + * off the mute. The LED is in the same circuit, so it reflects the
> >>> +true
> >>> + * state of the HW mute.  The reason for the EC "ack" is so that
> >>> +software
> >>> + * can first invoke a SW mute before the HW circuit is cut off.
> >>> +Without SW
> >>> + * cutting this off first does not affect the time delayed muting
> >>> +or status
> >>> + * of the LED but there is a possibility of a "popping" noise.
> >>> + *
> >>> + * If the EC receives the SW ack, the circuit will be activated
> >>> +before the
> >>> + * delay completed.
> >>> + *
> >>> + * Exposing as an LED device allows the codec drivers notification
> >>> +path to
> >>> + * EC ACK to work
> >>> + */
> >>> +static int dell_privacy_leds_setup(struct device *dev) {
> >>> +	struct privacy_wmi_data *priv = dev_get_drvdata(dev);
> >>> +
> >>> +	priv->cdev.name = "dell-privacy::micmute";
> >>> +	priv->cdev.max_brightness = 1;
> >>> +	priv->cdev.brightness_set_blocking = dell_privacy_micmute_led_set;
> >>> +	priv->cdev.default_trigger = "audio-micmute";
> >>> +	priv->cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
> >>> +	return devm_led_classdev_register(dev, &priv->cdev); }
> >>> +
> >>> +static int dell_privacy_wmi_probe(struct wmi_device *wdev, const
> >>> +void *context) {
> >>> +	struct privacy_wmi_data *priv;
> >>> +	struct key_entry *keymap;
> >>> +	int ret, i;
> >>> +
> >>> +	ret = wmi_has_guid(DELL_PRIVACY_GUID);
> >>> +	if (!ret)
> >>> +		pr_debug("Unable to detect available Dell privacy
> devices!\n");
> >>> +
> >>> +	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
> >>> +	if (!priv)
> >>> +		return -ENOMEM;
> >>> +
> >>> +	dev_set_drvdata(&wdev->dev, priv);
> >>> +	priv->wdev = wdev;
> >>> +	/* create evdev passing interface */
> >>> +	priv->input_dev = devm_input_allocate_device(&wdev->dev);
> >>> +	if (!priv->input_dev)
> >>> +		return -ENOMEM;
> >>> +
> >>> +	/* remap the wmi keymap event to new keymap */
> >>> +	keymap = kcalloc(ARRAY_SIZE(dell_wmi_keymap_type_0012),
> >>> +			sizeof(struct key_entry), GFP_KERNEL);
> >>> +	if (!keymap)
> >>> +		return -ENOMEM;
> >>> +
> >>> +	/* remap the keymap code with Dell privacy key type 0x12 as prefix
> >>> +	 * KEY_MICMUTE scancode will be reported as 0x120001
> >>> +	 */
> >>> +	for (i = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
> >>> +		keymap[i] = dell_wmi_keymap_type_0012[i];
> >>> +		keymap[i].code |= (0x0012 << 16);
> >>> +	}
> >>> +	ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
> >>> +	kfree(keymap);
> >>> +	if (ret)
> >>> +		return ret;
> >>> +
> >>> +	priv->input_dev->dev.parent = &wdev->dev;
> >>> +	priv->input_dev->name = "Dell Privacy Driver";
> >>> +	priv->input_dev->id.bustype = BUS_HOST;
> >>> +
> >>> +	ret = input_register_device(priv->input_dev);
> >>> +	if (ret)
> >>> +		return ret;
> >>> +
> >>> +	ret = get_current_status(priv->wdev);
> >>> +	if (ret)
> >>> +		return ret;
> >>> +
> >>> +	ret = devm_device_add_group(&wdev->dev,
> &privacy_attribute_group);
> >>> +	if (ret)
> >>> +		return ret;
> >>> +
> >>> +	if (priv->features_present & BIT(DELL_PRIVACY_TYPE_AUDIO)) {
> >>> +		ret = dell_privacy_leds_setup(&priv->wdev->dev);
> >>> +		if (ret)
> >>> +			return ret;
> >>> +	}
> >>> +	mutex_lock(&list_mutex);
> >>> +	list_add_tail(&priv->list, &wmi_list);
> >>> +	mutex_unlock(&list_mutex);
> >>> +	return 0;
> >>> +}
> >>> +
> >>> +static int dell_privacy_wmi_remove(struct wmi_device *wdev) {
> >>> +	struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
> >>> +
> >>> +	mutex_lock(&list_mutex);
> >>> +	list_del(&priv->list);
> >>> +	mutex_unlock(&list_mutex);
> >>> +	return 0;
> >>> +}
> >>> +
> >>> +static const struct wmi_device_id dell_wmi_privacy_wmi_id_table[] = {
> >>> +	{ .guid_string = DELL_PRIVACY_GUID },
> >>> +	{ },
> >>> +};
> >>> +
> >>> +static struct wmi_driver dell_privacy_wmi_driver = {
> >>> +	.driver = {
> >>> +		.name = "dell-privacy",
> >>> +	},
> >>> +	.probe = dell_privacy_wmi_probe,
> >>> +	.remove = dell_privacy_wmi_remove,
> >>> +	.id_table = dell_wmi_privacy_wmi_id_table, };
> >>> +
> >>> +module_wmi_driver(dell_privacy_wmi_driver);
> >>> +
> >>> +MODULE_DEVICE_TABLE(wmi, dell_wmi_privacy_wmi_id_table);
> >>> +MODULE_AUTHOR("Perry Yuan <perry_yuan@dell.com>");
> >>> +MODULE_DESCRIPTION("Dell Privacy WMI Driver");
> >>> +MODULE_LICENSE("GPL");
> >>> diff --git a/drivers/platform/x86/dell/dell-privacy-wmi.h
> >>> b/drivers/platform/x86/dell/dell-privacy-wmi.h
> >>> new file mode 100644
> >>> index 000000000000..54004eed7213
> >>> --- /dev/null
> >>> +++ b/drivers/platform/x86/dell/dell-privacy-wmi.h
> >>> @@ -0,0 +1,25 @@
> >>> +/* SPDX-License-Identifier: GPL-2.0-only */
> >>> +/*
> >>> + * Dell privacy notification driver
> >>> + *
> >>> + * Copyright (C) 2021 Dell Inc. All Rights Reserved.
> >>> + */
> >>> +
> >>> +#ifndef _DELL_PRIVACY_WMI_H_
> >>> +#define _DELL_PRIVACY_WMI_H_
> >>> +
> >>> +#if IS_ENABLED(CONFIG_DELL_PRIVACY) bool
> >>> +dell_privacy_present(void); bool dell_privacy_process_event(int
> >>> +type, int code, int status); #else /* CONFIG_DELL_PRIVACY */ static
> >>> +inline bool dell_privacy_present(void) {
> >>> +	return -ENODEV;
> >>> +}
> >>> +
> >>> +static inline bool dell_privacy_process_event(int type, int code,
> >>> +int status) {
> >>> +	return false;
> >>> +}
> >>> +#endif /* CONFIG_DELL_PRIVACY */
> >>> +#endif
> >>> diff --git a/drivers/platform/x86/dell/dell-wmi.c
> >>> b/drivers/platform/x86/dell/dell-wmi.c
> >>> index bbdb3e860892..20367a580fa0 100644
> >>> --- a/drivers/platform/x86/dell/dell-wmi.c
> >>> +++ b/drivers/platform/x86/dell/dell-wmi.c
> >>> @@ -27,6 +27,7 @@
> >>>  #include <acpi/video.h>
> >>>  #include "dell-smbios.h"
> >>>  #include "dell-wmi-descriptor.h"
> >>> +#include "dell-privacy-wmi.h"
> >>>
> >>>  MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
> >>> MODULE_AUTHOR("Pali Rohár <pali@kernel.org>"); @@ -427,7 +428,6
> @@
> >>> static void dell_wmi_notify(struct wmi_device *wdev,
> >>>
> >>>  		switch (buffer_entry[1]) {
> >>>  		case 0x0000: /* One key pressed or event occurred */
> >>> -		case 0x0012: /* Event with extended data occurred */
> >>>  			if (len > 2)
> >>>  				dell_wmi_process_key(wdev, buffer_entry[1],
> >>>  						     buffer_entry[2]);
> >>> @@ -439,6 +439,13 @@ static void dell_wmi_notify(struct wmi_device
> *wdev,
> >>>  				dell_wmi_process_key(wdev, buffer_entry[1],
> >>>  						     buffer_entry[i]);
> >>>  			break;
> >>> +		case 0x0012:
> >>> +			if ((len > 4) &&
> dell_privacy_process_event(buffer_entry[1], buffer_entry[3],
> >>> +
> buffer_entry[4]))
> >>> +				/* dell_privacy_process_event has handled
> the event */;
> >>> +			else if (len > 2)
> >>> +				dell_wmi_process_key(wdev, buffer_entry[1],
> buffer_entry[2]);
> >>> +			break;
> >>>  		default: /* Unknown event */
> >>>  			pr_info("Unknown WMI event type 0x%x\n",
> >>>  				(int)buffer_entry[1]);
> >>>