RE: [PATCH v5 1/2] platform/x86: dell-privacy: Add support for Dell hardware privacy
From: Yuan, Perry
Date: Thu Mar 25 2021 - 10:54:50 EST
Hi Hans.
Reviewing your feedback and working on next version below
> -----Original Message-----
> From: Hans de Goede <hdegoede@xxxxxxxxxx>
> Sent: Wednesday, March 24, 2021 7:19 PM
> To: Yuan, Perry; pobrn@xxxxxxxxxxxxxx; pierre-
> louis.bossart@xxxxxxxxxxxxxxx; oder_chiou@xxxxxxxxxxx; perex@xxxxxxxx;
> tiwai@xxxxxxxx; mgross@xxxxxxxxxxxxxxx; Limonciello, Mario
> Cc: lgirdwood@xxxxxxxxx; broonie@xxxxxxxxxx; alsa-devel@xxxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; platform-driver-x86@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v5 1/2] platform/x86: dell-privacy: Add support for Dell
> hardware privacy
>
>
> [EXTERNAL EMAIL]
>
> Hi,
>
> On 3/22/21 10:38 AM, Perry Yuan wrote:
> > From: Perry Yuan <perry_yuan@xxxxxxxx>
> >
> > 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@xxxxxxxx>
> > ---
> > 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@xxxxxxxx>"
> > +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@xxxxxxxx>"
> > +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@xxxxxxxx>");
> > +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@xxxxxxxx>");
> > +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@xxxxxxxxxx>");
> > MODULE_AUTHOR("Pali Rohár <pali@xxxxxxxxxx>"); @@ -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