Re: [PATCH v5 1/2] platform/x86: dell-privacy: Add support for Dell hardware privacy

Perry Yuan
2021-03-28T14:33:22Z

Hi Hans.

Thanks for your suggestion helping to improve the patch.

On 3/24/21 7:39 AM, Hans de Goede wrote:
> Hi,
>
> On 3/24/21 12:19 PM, Hans de Goede wrote:
>> Hi,
>>
>> On 3/22/21 10:38 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 emmits
>>> SW_CAMERA_LENS_COVER event while the camera lens shutter will be
>>> changed by EC & hw(hadware) 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.
>>>
>>> Signed-off-by: Perry Yuan <perry_yuan@dell.com>
> One last remark, I think that the dell_privacy_present() function which
> I suggested in my review should be renamed to:
>
> dell_privacy_has_micmute() and then its return should check the micmute
> feature bit in priv->features_present and this new function should then
> be used in dell-laptop.c to determine it dell-laptop.c should register
> its own mic-mute led_classdev.
>
> This way if a theoretical future laptop shows up where the micmute feature
> is not implemented by the privacy interface dell-laptop.c will still
> register the non-privacy mic-mute led_classdev.
>
> Regards,
>
> Hans

Yes, I rename the micmute checking function to dell_privacy_has_micmute.

and i rewrite it to simplify the micmute checking process.

I am doing some testing and drive other feedback to be finished.

Will post V6 soon for your confirm.

Perry.

>
>
>
>
>>> ---
>>> 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 | 32 ++
>>> drivers/platform/x86/dell/Kconfig | 16 +
>>> drivers/platform/x86/dell/Makefile | 3 +
>>> drivers/platform/x86/dell/dell-laptop.c | 23 +-
>>> drivers/platform/x86/dell/dell-privacy-acpi.c | 164 +++++++++
>>> drivers/platform/x86/dell/dell-privacy-wmi.c | 340 ++++++++++++++++++
>>> drivers/platform/x86/dell/dell-privacy-wmi.h | 35 ++
>>> drivers/platform/x86/dell/dell-wmi.c | 27 +-
>>> 8 files changed, 627 insertions(+), 13 deletions(-)
>>> create mode 100644 Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi
>>> create mode 100644 drivers/platform/x86/dell/dell-privacy-acpi.c
>>> 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..20c15a51ec38
>>> --- /dev/null
>>> +++ b/Documentation/ABI/testing/sysfs-platform-dell-privacy-wmi
>>> @@ -0,0 +1,32 @@
>>> +What: /sys/bus/wmi/devices/6932965F-1671-4CEB-B988-D3AB0A901919/devices_supported
>>> +Date: Feb 2021
>>> +KernelVersion: 5.12
>>> +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:
>>> + - 0 = Not Supported
>>> + - 1 = Supported
>>> + - Bit0 -> Microphone
>>> + - Bit1 -> Camera
>>> + - Bit2 -> ePrivacy Screen
>>> +
>>> +What: /sys/bus/wmi/devices/6932965F-1671-4CEB-B988-D3AB0A901919/current_state
>>> +Date: Feb 2021
>>> +KernelVersion: 5.12
>>> +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
>>> + There are three Bits for available states:
>>> + - 0 = Enabled
>>> + - 1 = Disabled
>> What is the definition of enabled/disabled ? Does enabled mean that the device
>> is enabled, or that the device is in privacy mode, so in case of the microphone
>> it is actually disabled (muted) ?
>>
>>> + - Bit0 -> Microphone
>>> + - Bit1 -> Camera
>>> + - Bit2 -> ePrivacyScreen
>>> +
>> Normally we would use strings for something like this and not direclty export a bitfield,
>> this would also allow avoiding the enabled / disabled ambiguity
>>
>> E.g. you could have the following:
>>
>> # supported devices
>> $ cat /sys/bus/wmi/devices/6932965F-1671-4CEB-B988-D3AB0A901919/devices_supported
>> Microphone Mute
>> Camera Shutter
>> ePrivacyScreen
>>
>> # All devices in privacy mode:
>> $ cat /sys/bus/wmi/devices/6932965F-1671-4CEB-B988-D3AB0A901919/current_state
>> Microphone muted
>> Camera Shutter closed
>> ePrivacyScreen privacy-filter enabled
>>
>> # All devices in non-privacy mode:
>>
>> $ cat /sys/bus/wmi/devices/6932965F-1671-4CEB-B988-D3AB0A901919/current_state
>> Microphone unmuted
>> Camera Shutter open
>> ePrivacyScreen privacy-filter disabled
>>
>> You can easily do the bitfield -> string mapping in the kernel by having 3
>> string arrays (support, privacy_on, privacy_off) indexed by the bitfield indices.
>>
>>
>>> diff --git a/drivers/platform/x86/dell/Kconfig b/drivers/platform/x86/dell/Kconfig
>>> index e0a55337f51a..0e0f1eb35bd6 100644
>>> --- a/drivers/platform/x86/dell/Kconfig
>>> +++ b/drivers/platform/x86/dell/Kconfig
>>> @@ -204,4 +204,20 @@ 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
>>> + help
>>> + This driver provides support for the "Dell Hardware Privacy" feature
>>> + of Dell laptops.
>>> + Support for a micmute and camera mute privacy will be provided as
>>> + hardware button Ctrl+F4 and Ctrl+F9 hotkey.
>> This suggests that that the driver implements the buttons, which is not the
>> case. How about:
>>
>> 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..8b0883ee9412 100644
>>> --- a/drivers/platform/x86/dell/Makefile
>>> +++ b/drivers/platform/x86/dell/Makefile
>>> @@ -19,3 +19,6 @@ 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.o
>>> +dell-privacy-objs := dell-privacy-wmi.o \
>>> + dell-privacy-acpi.o
>>> diff --git a/drivers/platform/x86/dell/dell-laptop.c b/drivers/platform/x86/dell/dell-laptop.c
>>> index 70edc5bb3a14..4c840ab6cb59 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;
>>>
>>> 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 (!privacy_valid)
>> This privacy_valid variable is coming from another module, so you're adding
>> a "privacy_valid" symbol to the global kernel symbol namespace, even though this is
>> dell specific. Please use the dell_privacy_present() function (see below) instead, so you get:
>>
>> if (dell_privacy_present())
>> has_privacy = true;
>> else
>> has_privacy = false;
>>
>> Which makes much more sense then "if (!privacy_valid) has_privacy = true;" which
>> feels as if it is inverted to what it should be.
>>
>>> + 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;
>>> + }
>>> }
>>>
>>> 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)
>>> + led_classdev_unregister(&micmute_led_cdev);
>>> 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)
>>> + 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-acpi.c b/drivers/platform/x86/dell/dell-privacy-acpi.c
>>> new file mode 100644
>>> index 000000000000..4c785b62c7c4
>>> --- /dev/null
>>> +++ b/drivers/platform/x86/dell/dell-privacy-acpi.c
>>> @@ -0,0 +1,164 @@
>>> +// 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/bits.h>
>>> +#include <linux/device.h>
>>> +#include <linux/fs.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/leds.h>
>>> +#include <linux/module.h>
>>> +#include <linux/mutex.h>
>>> +#include <linux/platform_device.h>
>>> +#include <linux/string.h>
>>> +#include <linux/sysfs.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/types.h>
>>> +#include <linux/wmi.h>
>>> +
>>> +#include "dell-privacy-wmi.h"
>>> +
>>> +#define PRIVACY_PLATFORM_NAME "dell-privacy-acpi"
>>> +#define DELL_PRIVACY_GUID "6932965F-1671-4CEB-B988-D3AB0A901919"
>>> +
>>> +struct privacy_acpi_priv {
>>> + struct device *dev;
>>> + struct platform_device *platform_device;
>>> + struct led_classdev cdev;
>>> +};
>>> +static struct privacy_acpi_priv *privacy_acpi;
>>> +
>>> +static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
>>> + enum led_brightness brightness)
>>> +{
>>> + struct privacy_acpi_priv *priv = privacy_acpi;
>> Please use container_of on the passed in led_cdev here instead
>> of relying on a global variable.
>>
>>> + acpi_status status;
>>> + acpi_handle handle;
>>> + static char *acpi_method = (char *)"ECAK";
>>> +
>>> + 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->dev, "Error setting privacy EC ack value: %s\n",
>>> + acpi_format_exception(status));
>>> + return -EIO;
>>> + }
>>> + pr_debug("set dell privacy micmute ec ack event done\n");
>>> + return 0;
>>> +}
>>> +
>>> +static int dell_privacy_acpi_remove(struct platform_device *pdev)
>>> +{
>>> + struct privacy_acpi_priv *priv = dev_get_drvdata(privacy_acpi->dev);
>>> +
>>> + led_classdev_unregister(&priv->cdev);
>>> +
>>> + 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_acpi_priv *priv = dev_get_drvdata(dev);
>>> + int ret = 0;
>>> +
>>> + 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);
>>> + ret = devm_led_classdev_register(dev, &priv->cdev);
>>> + if (ret)
>>> + return ret;
>>> + return 0;
>>> +}
>>> +
>>> +static int dell_privacy_acpi_probe(struct platform_device *pdev)
>>> +{
>>> + int ret;
>>> +
>>> + platform_set_drvdata(pdev, privacy_acpi);
>>> + privacy_acpi->dev = &pdev->dev;
>>> + privacy_acpi->platform_device = pdev;
>>> +
>>> + ret = dell_privacy_leds_setup(&pdev->dev);
>>> + if (ret)
>>> + return -EIO;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static struct platform_driver dell_privacy_platform_drv = {
>>> + .driver = {
>>> + .name = PRIVACY_PLATFORM_NAME,
>>> + },
>>> + .probe = dell_privacy_acpi_probe,
>>> + .remove = dell_privacy_acpi_remove,
>>> +};
>>> +
>>> +int __init dell_privacy_acpi_init(void)
>>> +{
>>> + int err;
>>> + struct platform_device *pdev;
>>> +
>>> + if (!wmi_has_guid(DELL_PRIVACY_GUID))
>>> + return -ENODEV;
>>> +
>>> + privacy_acpi = kzalloc(sizeof(*privacy_acpi), GFP_KERNEL);
>>> + if (!privacy_acpi)
>>> + return -ENOMEM;
>>> +
>>> + err = platform_driver_register(&dell_privacy_platform_drv);
>>> + if (err)
>>> + goto pdrv_err;
>>> +
>>> + pdev = platform_device_register_simple(
>>> + PRIVACY_PLATFORM_NAME, PLATFORM_DEVID_NONE, NULL, 0);
>>> + if (IS_ERR(pdev)) {
>>> + err = PTR_ERR(pdev);
>>> + goto pdev_err;
>>> + }
>> So you're creating a platform_device here, from code called from the
>> init_dell_privacy() function in dell-privacy-wmi.c, just so that
>> the probe() function for that platform-device can register the
>> led_classdev for the (alternative) mute LED.
>>
>> Please just put the cdev struct inside struct privacy_wmi_data
>> and call dell_privacy_leds_setup() with the wmi-dev as parameter
>> from dell_privacy_wmi_probe and have the wmi-dev as the parent
>> of the led_classdev.
>>
>> This allows removing both the platform-driver and the instantiation
>> of the platform-device.
>>
>> After removing the unnecessary platfrom-dev/driver there will be
>> so little left of dell-privacy-acpi.c, that what remains can and
>> should just be folded into dell-privacy-wmi.c. At which point
>> you're down to one file for the module which also simplifies the
>> Makefile.
>>
>>> +
>>> + return 0;
>>> +
>>> +pdev_err:
>>> + platform_device_unregister(pdev);
>>> +pdrv_err:
>>> + kfree(privacy_acpi);
>>> + return err;
>>> +}
>>> +
>>> +void __exit dell_privacy_acpi_exit(void)
>>> +{
>>> + struct platform_device *pdev = to_platform_device(privacy_acpi->dev);
>>> +
>>> + platform_device_unregister(pdev);
>>> + platform_driver_unregister(&dell_privacy_platform_drv);
>>> + kfree(privacy_acpi);
>>> +}
>>> +
>>> +MODULE_AUTHOR("Perry Yuan <perry_yuan@dell.com>");
>>> +MODULE_DESCRIPTION("DELL Privacy ACPI Driver");
>>> +MODULE_LICENSE("GPL");
>>> 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..8bde97613477
>>> --- /dev/null
>>> +++ b/drivers/platform/x86/dell/dell-privacy-wmi.c
>>> @@ -0,0 +1,340 @@
>>> +// 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/input.h>
>>> +#include <linux/input/sparse-keymap.h>
>>> +#include <linux/list.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 PRIVACY_SCREEN_STATUS BIT(2)
>>> +
>>> +/*
>>> + * The wmi_list is used to store the privacy_priv struct with mutex protecting
>>> + */
>>> +static LIST_HEAD(wmi_list);
>>> +static DEFINE_MUTEX(list_mutex);
>>> +/*
>>> + * 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
>>> + */
>>> +int privacy_valid = -EPROBE_DEFER;
>>> +EXPORT_SYMBOL_GPL(privacy_valid);
>> None of the callers are interpreting the error-codes stored here.
>> So this is really treated as a bool, and the info stored in the bool
>> is already available inside the wmi_list-head. So just drop this.
>>
>>> +
>>> +struct privacy_wmi_data {
>>> + struct input_dev *input_dev;
>>> + struct wmi_device *wdev;
>>> + struct list_head list;
>>> + u32 features_present;
>>> + u32 last_status;
>>> +};
>>> +
>>> +/*
>>> + * 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},
>>> +};
>>> +
>>> +int dell_privacy_state(void)
>> Please rename this to dell_privacy_present(), "state" is very generic / not descriptive
>> and use list_first_entry_or_null(&wmi_list) as done in dell_privacy_process_event(), e.g.:
>>
>> 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;
>> }
>>
>>
>>
>>> +{
>>> + return privacy_valid;
>>> +}
>>> +EXPORT_SYMBOL_GPL(dell_privacy_state);
>>> +/*
>>> + * 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.
>>> + */
>>> +void dell_privacy_process_event(int type, int code, int status)
>> Please make this return a bool, returning true when it has consumed the event
>> and false when it did not consume the event. This will allow other 0x0012 0xXXXX
>> codes to still be handled by the existing dell-wmi.c code for this.
>>
>>> +{
>>> + 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) {
>>> + pr_err("dell privacy priv is NULL\n");
>>> + goto error;
>>> + }
>>> + key = sparse_keymap_entry_from_scancode(priv->input_dev, (type << 16) | code);
>>> + if (!key) {
>>> + dev_dbg(&priv->wdev->dev, "Unknown key with type 0x%04x and code 0x%04x pressed\n",
>>> + type, code);
>>> + goto error;
>>> + }
>>> + switch (code) {
>>> + case DELL_PRIVACY_TYPE_AUDIO: /* Mic mute */
>>> + priv->last_status = status;
>>> + sparse_keymap_report_entry(priv->input_dev, key, 1, true);
>> ret = true;
>>
>>> + break;
>>> + case DELL_PRIVACY_TYPE_CAMERA: /* Camera mute */
>>> + priv->last_status = status;
>>> + sparse_keymap_report_entry(priv->input_dev, key, 1, true);
>> ret = true;
>>
>>> + break;
>> These 2 cases are exactly the same, please merge them into a single case.
>>
>>> + default:
>>> + dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x 0x%04x",
>>> + type, code);
>>> + }
>>> +
>>> +error:
>>> + mutex_unlock(&list_mutex);
>> return ret;
>>> +}
>>> +EXPORT_SYMBOL_GPL(dell_privacy_process_event);
>>> +
>>> +static ssize_t devices_supported_show(struct device *dev,
>>> + struct device_attribute *attr,
>>> + char *buf)
>>> +{
>>> + struct privacy_wmi_data *priv = dev_get_drvdata(dev);
>>> +
>>> + return sysfs_emit(buf, "%x\n", priv->features_present);
>>> +}
>>> +
>>> +static ssize_t current_state_show(struct device *dev,
>>> + struct device_attribute *attr,
>>> + char *buf)
>>> +{
>>> + struct privacy_wmi_data *priv = dev_get_drvdata(dev);
>>> +
>>> + return sysfs_emit(buf, "%x\n", priv->last_status);
>>> +}
>> Please change these to emit strings as discussed above
>> (assuming you agree with my above proposal for this).
>>
>>> +
>>> +static DEVICE_ATTR_RO(devices_supported);
>>> +static DEVICE_ATTR_RO(current_state);
>>> +
>>> +static struct attribute *privacy_attributes[] = {
>>> + &dev_attr_devices_supported.attr,
>>> + &dev_attr_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) {
>>> + pr_err("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");
>>> + ret = -EIO;
>>> + privacy_valid = ret;
>>> + return ret;
>>> + }
>>> +
>>> + if (obj_present->type != ACPI_TYPE_BUFFER) {
>>> + dev_err(&wdev->dev, "Binary MOF is not a buffer!\n");
>>> + ret = -EIO;
>>> + privacy_valid = ret;
>>> + 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;
>>> + privacy_valid = ret;
>>> + goto obj_free;
>>> + }
>>> + buffer = (u32 *)obj_present->buffer.pointer;
>>> + priv->features_present = buffer[0];
>>> + priv->last_status = buffer[1];
>>> + privacy_valid = 0;
>> As discussed, there is no need for the privacy_valid variable, remove all
>> references to it here.
>>
>>> +
>>> +obj_free:
>>> + kfree(obj_present);
>>> + return ret;
>>> +}
>>> +
>>> +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;
>>> +
>>> + 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) {
>>> + ret = -ENOMEM;
>>> + goto err_free_dev;
>>> + }
>> No need for the goto here just simplify this to:
>>
>> 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);
>> You're done with the keymap here, please put a single:
>>
>> kfree(keymap);
>>
>> Here before the if (ret), then you won't need any goto style
>> cleanup anywhere in this function.
>>
>> This also fixes not free-ing the keymap when sparse_keymap_setup() fails.
>>
>>> + 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;
>>> + if (input_register_device(priv->input_dev)) {
>>> + pr_debug("input_register_device failed to register!\n");
>> You're not setting ret here.
>>
>>> + goto err_free_keymap;
>>> + }
>> No need for the pr_debug, the kernel will already complain if this fails.
>> Also since all your resources are devm managed and we've already taken
>> care of the keymap this can be simplified to:
>>
>> ret = input_register_device(priv->input_dev);
>> if (ret)
>> returm ret;
>>
>>> + mutex_lock(&list_mutex);
>>> + list_add_tail(&priv->list, &wmi_list);
>>> + mutex_unlock(&list_mutex);
>> Move this to directly above the return 0; below, see below.
>>
>>> +
>>> + if (get_current_status(priv->wdev))
>>> + goto err_free_input;
>> You're again not setting ret here before the goto.
>>
>> And you are returning with an error here after adding the device to the wmi_list,
>> the list_add_tail call should be done last, directly above the return 0 call.
>>
>> Also since all your resources are devm managed and we've already taken
>> care of the keymap this can be simplified to:
>>
>> ret = get_current_status(priv->wdev);
>> if (ret)
>> return ret;
>>
>>> +
>>> + ret = devm_device_add_group(&wdev->dev, &privacy_attribute_group);
>>> + if (ret)
>>> + goto err_free_input;
>> Replace the goto err_free_input() with return ret;
>>
>>> +
>>> + kfree(keymap);
>> Drop this kfree() (already done above now).
>>
>> Move the list_add_tail() here.
>>
>>> + return 0;
>>> +
>>> +err_free_input:
>>> + input_unregister_device(priv->input_dev);
>> This is not necessary for an input_device allocated with devm_input_allocate_device(),
>> which means that none of these error handling labels are necessary now, so this can
>> all be removed.
>>
>>
>>
>>> +err_free_keymap:
>>> + privacy_valid = -ENODEV;
>>> + kfree(keymap);
>>> +err_free_dev:
>>> + return ret;
>>> +}
>>> +
>>> +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);
>>> + privacy_valid = -ENODEV;
>>> + input_unregister_device(priv->input_dev);
>> The input_unregister is not necessary (and privacy_valid is gone too).
>>
>>> +
>>> + 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,
>>> +};
>>> +
>>> +static int __init init_dell_privacy(void)
>>> +{
>>> + int ret;
>>> +
>>> + ret = wmi_has_guid(DELL_PRIVACY_GUID);> + if (!ret) {
>>> + privacy_valid = -ENODEV;
>>> + pr_debug("Unable to detect available Dell privacy devices: %d\n", ret);
>>> + return privacy_valid;
>>> + }
>> This driver will only get modprobed if the GUID is present and when it is
>> not present then loading the driver is a no-op so this can be checked.
>>
>>> +
>>> + ret = wmi_driver_register(&dell_privacy_wmi_driver);
>>> + if (ret) {
>>> + pr_err("failed to initialize privacy wmi driver: %d\n", ret);
>>> + return ret;
>>> + }
>>> +
>>> + ret = dell_privacy_acpi_init();
>>> + if (ret) {
>>> + pr_err("failed to initialize privacy acpi driver: %d\n", ret);
>>> + goto err_init;
>>> + }
>> And with the platform-device/driver removed this is not necessary too,
>> which means ...
>>
>>> +
>>> + return 0;
>>> +
>>> +err_init:
>>> + wmi_driver_unregister(&dell_privacy_wmi_driver);
>>> + return ret;
>>> +}
>>> +
>>> +static void dell_privacy_wmi_exit(void)
>>> +{
>>> + wmi_driver_unregister(&dell_privacy_wmi_driver);
>>> +}
>>> +
>>> +static void __exit exit_dell_privacy(void)
>>> +{
>>> + dell_privacy_wmi_exit();
>>> + dell_privacy_acpi_exit();
>>> +}
>>> +
>>> +module_init(init_dell_privacy);
>>> +module_exit(exit_dell_privacy);
>> That all of the init_dell_privacy / exit_dell_privacy stuff can be replaced with
>> a single line:
>>
>> 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..6dda2990df5d
>>> --- /dev/null
>>> +++ b/drivers/platform/x86/dell/dell-privacy-wmi.h
>>> @@ -0,0 +1,35 @@
>>> +/* 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)
>>> +extern int privacy_valid;
>> Please remove this from the global kernel namespace
>> (make it a static global inside the dell-privacy-wmi.c code).
>>
>>> +int dell_privacy_state(void);
>>> +void dell_privacy_process_event(int type, int code, int status);
>>> +#else /* CONFIG_DELL_PRIVACY */
>>> +int privacy_valid = -ENODEV;
>> Drop this.
>>
>>> +static inline int dell_privacy_state(void)
>>> +{
>>> + return privacy_valid;
>> And directly return -ENODEV here.
>>
>>> +}
>>> +
>>> +static inline void dell_privacy_process_event(int type, int code, int status)
>>> +{}
>>> +#endif /* CONFIG_DELL_PRIVACY */
>>> +
>>> +int dell_privacy_acpi_init(void);
>>> +void dell_privacy_acpi_exit(void);
>>> +
>>> +/* DELL Privacy Type */
>>> +enum {
>>> + DELL_PRIVACY_TYPE_UNKNOWN = 0x0,
>>> + DELL_PRIVACY_TYPE_AUDIO,
>>> + DELL_PRIVACY_TYPE_CAMERA,
>>> +};
>> This enum is only used inside dell-privacy-wmi.c, please move it there.
>>
>>> +#endif
>> With the platform-device/driver removal discussed above all this header file
>> needs to do is defines the prototypes / stubs for 2 functions:
>>
>> int dell_privacy_state(void);
>> void dell_privacy_process_event(int type, int code, int status);
>>
>> I think it would be best to just add these to dell-smbios.h, rather then
>> adding a new header just for these 2 prototypes / stubs.
>>
>>
>>> diff --git a/drivers/platform/x86/dell/dell-wmi.c b/drivers/platform/x86/dell/dell-wmi.c
>>> index bbdb3e860892..389e86de24b0 100644
>>> --- a/drivers/platform/x86/dell/dell-wmi.c
>>> +++ b/drivers/platform/x86/dell/dell-wmi.c
>>> @@ -13,20 +13,22 @@
>>>
>>> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>>
>>> -#include <linux/kernel.h>
>>> -#include <linux/module.h>
>>> +#include <linux/acpi.h>
>>> +#include <linux/dmi.h>
>>> #include <linux/init.h>
>>> -#include <linux/slab.h>
>>> -#include <linux/types.h>
>>> #include <linux/input.h>
>>> #include <linux/input/sparse-keymap.h>
>>> -#include <linux/acpi.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/module.h>
>>> +#include <linux/slab.h>
>>> #include <linux/string.h>
>>> -#include <linux/dmi.h>
>>> +#include <linux/types.h>
>>> #include <linux/wmi.h>
>>> #include <acpi/video.h>
>>> +
>> Please split the changes sorting these includes alphabetically out
>> into a separate cleanup patch.
>>
>>> #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>");
>>> @@ -381,6 +383,7 @@ static void dell_wmi_notify(struct wmi_device *wdev,
>>> u16 *buffer_entry, *buffer_end;
>>> acpi_size buffer_size;
>>> int len, i;
>>> + int err;
>> Drop this.
>>
>>>
>>> if (obj->type != ACPI_TYPE_BUFFER) {
>>> pr_warn("bad response type %x\n", obj->type);
>>> @@ -427,7 +430,6 @@ 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 +441,17 @@ static void dell_wmi_notify(struct wmi_device *wdev,
>>> dell_wmi_process_key(wdev, buffer_entry[1],
>>> buffer_entry[i]);
>>> break;
>>> + case 0x0012:
>>> + err = dell_privacy_state();
>>> + if (err == 0) {
>>> + dell_privacy_process_event(buffer_entry[1],
>>> + buffer_entry[3], buffer_entry[4]);
>> This needs a len > 4 check !
>>
>>> + } else {
>>> + if (len > 2)
>>> + dell_wmi_process_key(wdev, buffer_entry[1],
>>> + buffer_entry[2]);
>>> + }
>> Combined with the change to have dell_privacy_process_event() return a bool, this should
>> look something like this:
>>
>> if (len > 4 && dell_privacy_process_event(buffer_entry[1], buffer_entry[3], buffer_entry[4]))
>> ; /* Handled by dell_privacy_process_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
>>