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

Hans de Goede
2021-03-24T11:39:44Z

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

>> ---
>> 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
>