RE: [PATCH v7 1/2] platform/x86: dell-privacy: Add support for Dell hardware privacy

6 May 2021

Hi Hans.
I changed the driver in V8 as your comments.
Just one Kconfig change , It will cause some built error .
...
-----Original Message-----
From: Hans de Goede hdegoede@redhat.com
Sent: 2021年4月13日 16:48
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 v7 1/2] platform/x86: dell-privacy: Add support for Dell
hardware privacy
[EXTERNAL EMAIL]
Hi,
On 4/12/21 11:19 AM, 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:

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
v5 -> v6:

addressed feedback from Hans
addressed feedback from Pierre
optimize some debug format with dev_dbg()
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

Thank you, almost there. A few small remarks inline.
...
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       |  23 +-
 drivers/platform/x86/dell/dell-privacy-wmi.c  | 394
++++++++++++++++++  drivers/platform/x86/dell/dell-privacy-wmi.h  |  23 +
 drivers/platform/x86/dell/dell-wmi.c          |   8 +-
 7 files changed, 511 insertions(+), 7 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..05d124442b25 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
select DELL_WMI

DELL_WMI is not a helper library which can be selected, please use depends
on here.
More in general I'm a bit worried about the dependencies being added to dell-
laptop.c and dell-wmi.c on the new dell-privacy-wmi.ko module.
What if e.g. dell-laptop.c gets builtin while dell-privacy-wmi.c is a module.
Then we have dell-laptop.c depending on the dell_privacy_present linker-
symbol, but that symbol is in a module, so the main vmlinuz binary will fail to
link due to that missing symbol.
To fix this you need to add:
depends on DELL_PRIVACY || DELL_PRIVACY = n
To the Kconfig sections for both DELL_WMI and DELL_LAPTOP
If I add "depends on DELL_PRIVACY || DELL_PRIVACY = n" to both DELL_WMI and DELL_LAPTOP
The compile will report error "recursive dependency detected"
I do not think the dell-laptop will be builtin option as we know.
I am confused that why the symbol will be failed to link like that ?
because the compiler can find the dell_privacy_present which is defined in one common header file.
...
...

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..e7ffc0b81208 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 has_privacy;
There is a problem in the del-laptop.c code with the led_classdev
unregistering which is not introduced by this patch, but this patch is a good
opportunity to fix this.
The problem is that in the dell_init error-exit path as well as in dell_exit
led_classdev_unregister() gets called unconditionally, while the registering
has only happened under the following condition:
if (dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE) &&
       dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE)) {
So this means that the code may end up unregistering a never registered
led_classdev which is not good.
Since you are making the unregistering conditional in this patch, it would be
good to also fix this issue.
Please change:
static bool has_privacy;
To:
static bool micmute_led_registered;
...
module_param(force_rfkill, bool, 0444);
MODULE_PARM_DESC(force_rfkill, "enable rfkill on non whitelisted
models"); @@ -2206,10 +2209,16 @@ static int __init dell_init(void)
if (dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE) &&
       dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE)) {

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;




if (dell_privacy_present())


	has_privacy = true;


else


	has_privacy = false;


if (!has_privacy) {


	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;


}

}

And change this block to
if (dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE) &&
       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;
   }
This also looks cleaner/nicer with one less indent level too :)
...
if (acpi_video_get_backlight_type() != acpi_backlight_vendor) @@
-2257,7 +2266,8 @@ static int __init dell_init(void)
 fail_get_brightness:
   backlight_device_unregister(dell_backlight_device);
 fail_backlight:

led_classdev_unregister(&micmute_led_cdev);


if (!has_privacy)

Change this to:
if (micmute_led_registered)
...

led_classdev_unregister(&micmute_led_cdev);



This way the if condition also is more logical / easier to see why the if is there.
...
fail_led:
   dell_cleanup_rfkill();
 fail_rfkill:
@@ -2278,7 +2288,8 @@ 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 (!has_privacy)

And here too, change this to:
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..4be7548d1a03
--- /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;

+}
+EXPORT_SYMBOL_GPL(dell_privacy_present);
I thought that we had chaned this to dell_privacy_has_mic_mute ?
Returning:
return priv && (priv->features_present &
BIT(DELL_PRIVACY_TYPE_AUDIO));
?
What has happened to that change, please change that back, the only user of
dell_privacy_present() is dell-laptop.c and that wants to know if dell-privacy.c
will be handling the mute-led or not, so only checking for dell-privacy
presence is not enough.
...



+/*


The flow of privacy event:




User presses key. HW does stuff with this key (timeout is





+started)



WMI event is emitted from BIOS






WMI event is received by dell-privacy






KEY_MICMUTE emitted from dell-privacy






Userland picks up key and modifies kcontrol for SW mute






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);
...



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 <<


| 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;
char *s = buf;

privacy_list = priv->features_present;
for (type = DELL_PRIVACY_TYPE_AUDIO; type <

DELL_PRIVACY_TYPE_MAX; type++) {
...

if (privacy_list & BIT(type))


	s += sprintf(s, "[%s] [supported]\n",



privacy_types[type]);
...

else


	s += sprintf(s, "[%s] [unsupported]\n",



privacy_types[type]);
...

}

return (s - buf);

+}
As mentioned before I think (not sure), please use sysfs_emit_at here, like this:
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;
}
This will ensure that we never overrun the size of the passed in buffer.
...



+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;
char *s = buf;

for (type = DELL_PRIVACY_TYPE_AUDIO; type <

DELL_PRIVACY_TYPE_MAX; type++) {
...

if (privacy_supported & BIT(type)) {


	if (privacy_state & BIT(type))


		s += sprintf(s, "[%s] [unmuted]\n",



privacy_types[type]);
...

	else


		s += sprintf(s, "[%s] [muted]\n",



privacy_types[type]);
...

}


}

return (s - buf);

+}
And the same here.
...



+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;



ret = dell_privacy_leds_setup(&priv->wdev->dev);
if (ret)
return ret;



This should be conditional on the audio privacy feature being supported:
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..04c49d2fa924
--- /dev/null
+++ b/drivers/platform/x86/dell/dell-privacy-wmi.h
@@ -0,0 +1,23 @@
+/* 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) {}
This is missing a return false; between the {}.
...
+#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..228e85a427f5 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 +439,12 @@ 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]))
...

		/* privacy hotkey handle */;



Please change this comment to:
		/* 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]);

Regards,
Hans

    