Re: [PATCH v2 1/2] platform/x86: dell-privacy: Add support for Dell hardware privacy
From: Barnabás Pőcze
Date: Mon Dec 28 2020 - 18:07:59 EST
Hi
Firstly, a minor note: the newly created sysfs attributes are not documented, so
I believe you should either move them to debugfs or add documentation. And I
believe you might have forgotten to send the second patch in the series.
I added a couple comments regarding the code, but unfortunately I believe there
are deeper, architectural problems. I cannot help but think that this is a bit
over-complicated with its 1 platform device, 1 platform driver, 1 WMI driver,
2 source files, not-immediately-clear relationship between the two "submodules",
and (a bit) forced integration with the dell-wmi module.
If it were up to me I would do it the simplest way: a single module,
exports dell_privacy_is_ok() and dell_privacy_event(); its probe checks the WMI
GUID, the EC handle, and the ECAK method; registers a single platform device
with PLATFORM_DEVID_NONE and with the necessary attributes (devices_supported,
current_state); registers the LED and input device under the platform device.
But, of course, you should wait for Hans or Mark to see what they'd prefer.
2020. december 28., hétfő 14:28 keltezéssel, Perry Yuan írta:
> 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 enabled, 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.
I believe at the first occurrence of "EC" it should be noted what it stands for.
> and camera mute hotkey is ctrl+F9.currently design only emmit
> SW_CAMERA_LENS_COVER event while the camera LENS shutter will be
Why is "LENS" capitalized?
> changed by EC & HW control.
>
> *The flow is like this:
> 1) User presses key. HW does stuff with this key (timeout is started)
> 2) Event is emitted from FW
> 3) Event 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.
>
Please proofread the commit message again, and pay attention to capitalization
and spacing.
> Signed-off-by: Perry Yuan <perry_yuan@xxxxxxxx>
> Signed-off-by: Limonciello Mario <mario_limonciello@xxxxxxxx>
> ---
> 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
> ---
> ---
> drivers/platform/x86/Kconfig | 17 ++
> drivers/platform/x86/Makefile | 4 +-
> drivers/platform/x86/dell-laptop.c | 29 ++-
> drivers/platform/x86/dell-privacy-acpi.c | 165 ++++++++++++
> drivers/platform/x86/dell-privacy-wmi.c | 309 +++++++++++++++++++++++
> drivers/platform/x86/dell-privacy-wmi.h | 33 +++
> drivers/platform/x86/dell-wmi.c | 26 +-
> 7 files changed, 567 insertions(+), 16 deletions(-)
> create mode 100644 drivers/platform/x86/dell-privacy-acpi.c
> create mode 100644 drivers/platform/x86/dell-privacy-wmi.c
> create mode 100644 drivers/platform/x86/dell-privacy-wmi.h
>
> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> index 91e6176cdfbd..9d5cc2454b3e 100644
> --- a/drivers/platform/x86/Kconfig
> +++ b/drivers/platform/x86/Kconfig
> @@ -491,6 +491,23 @@ config DELL_WMI_LED
> This adds support for the Latitude 2100 and similar
> notebooks that have an external LED.
>
> +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
> +
> + To compile this driver as a module, choose M here: the module will
> + be called dell_privacy.
> +
> config AMILO_RFKILL
> tristate "Fujitsu-Siemens Amilo rfkill support"
> depends on RFKILL
> diff --git a/drivers/platform/x86/Makefile b/drivers/platform/x86/Makefile
> index 581475f59819..18c430456de7 100644
> --- a/drivers/platform/x86/Makefile
> +++ b/drivers/platform/x86/Makefile
> @@ -51,7 +51,9 @@ obj-$(CONFIG_DELL_WMI_DESCRIPTOR) += dell-wmi-descriptor.o
> obj-$(CONFIG_DELL_WMI_AIO) += dell-wmi-aio.o
> obj-$(CONFIG_DELL_WMI_LED) += dell-wmi-led.o
> obj-$(CONFIG_DELL_WMI_SYSMAN) += dell-wmi-sysman/
> -
> +obj-$(CONFIG_DELL_PRIVACY) += dell-privacy.o
> +dell-privacy-objs := dell-privacy-wmi.o \
> + dell-privacy-acpi.o
> # Fujitsu
> obj-$(CONFIG_AMILO_RFKILL) += amilo-rfkill.o
> obj-$(CONFIG_FUJITSU_LAPTOP) += fujitsu-laptop.o
> diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
> index 70edc5bb3a14..ea0c8a8099ff 100644
> --- a/drivers/platform/x86/dell-laptop.c
> +++ b/drivers/platform/x86/dell-laptop.c
> @@ -30,6 +30,7 @@
> #include <acpi/video.h>
> #include "dell-rbtn.h"
> #include "dell-smbios.h"
> +#include "dell-privacy-wmi.h"
>
> struct quirk_entry {
> bool touchpad_led;
> @@ -90,6 +91,7 @@ static struct rfkill *wifi_rfkill;
> static struct rfkill *bluetooth_rfkill;
> static struct rfkill *wwan_rfkill;
> static bool force_rfkill;
> +static bool privacy_valid;
>
> module_param(force_rfkill, bool, 0444);
> MODULE_PARM_DESC(force_rfkill, "enable rfkill on non whitelisted models");
> @@ -1587,10 +1589,10 @@ static ssize_t kbd_led_timeout_store(struct device *dev,
> switch (unit) {
> case KBD_TIMEOUT_DAYS:
> value *= 24;
> - fallthrough;
> + /* fall through */
> case KBD_TIMEOUT_HOURS:
> value *= 60;
> - fallthrough;
> + /* fall through */
What is the reason behind changing "fallthrough;" to a comment?
> case KBD_TIMEOUT_MINUTES:
> value *= 60;
> unit = KBD_TIMEOUT_SECONDS;
> @@ -2205,11 +2207,18 @@ static int __init dell_init(void)
> dell_laptop_register_notifier(&dell_laptop_notifier);
>
> if (dell_smbios_find_token(GLOBAL_MIC_MUTE_DISABLE) &&
> - dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE)) {
> - 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;
> + dell_smbios_find_token(GLOBAL_MIC_MUTE_ENABLE)) {
> +#if IS_ENABLED(CONFIG_DELL_PRIVACY)
> + ret = dell_privacy_valid();
> + if (!ret)
> + privacy_valid = true;
> +#endif
> + if (!privacy_valid) {
> + 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 (!privacy_valid)
> + 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 (!privacy_valid)
> + led_classdev_unregister(&micmute_led_cdev);
> dell_cleanup_rfkill();
> if (platform_device) {
> platform_device_unregister(platform_device);
> diff --git a/drivers/platform/x86/dell-privacy-acpi.c b/drivers/platform/x86/dell-privacy-acpi.c
> new file mode 100644
> index 000000000000..fef781555b67
> --- /dev/null
> +++ b/drivers/platform/x86/dell-privacy-acpi.c
> @@ -0,0 +1,165 @@
> +// 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/device.h>
> +#include <linux/fs.h>
> +#include <linux/kernel.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/string.h>
> +#include <linux/sysfs.h>
> +#include <linux/types.h>
> +#include <linux/wmi.h>
> +#include <linux/slab.h>
> +#include <linux/bits.h>
> +#include <linux/mutex.h>
> +#include <linux/platform_device.h>
> +#include "dell-privacy-wmi.h"
I believe it would be preferable to sort the list of includes lexicographically.
("dell-privacy-wmi.h" can remain separate)
> +
> +#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;
Any reason it needs to be dynamically allocated?
> +
> +static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
> + enum led_brightness brightness)
> +{
> + struct privacy_acpi_priv *priv = privacy_acpi;
> + acpi_status status;
> + acpi_handle handle;
> + char *acpi_method;
> +
> + handle = ec_get_handle();
> + if (!handle)
> + return -EIO;
> + if (acpi_has_method(handle, "ECAK"))
> + acpi_method = "ECAK";
> + else
> + return -ENODEV;
I find this if-else a bit cumbersome. Any reason why
if (!acpi_has_method(handle, "ECAK"))
return ...;
would not work? I believe you could also easily do away with the `acpi_method`
variable.
> +
> + 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;
> + }
> + 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);
> + dev_set_drvdata(&pdev->dev, NULL);
This is not needed as the driver sets the driver data to NULL when a driver
unbinds from a device.
> +
> + 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 void dell_privacy_leds_setup(struct device *dev)
> +{
> + struct privacy_acpi_priv *priv = dev_get_drvdata(dev);
> +
> + priv->cdev.name = "privacy::micmute";
Maybe "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);
> + priv->cdev.dev = dev;
There is no need for this assignment.
> + devm_led_classdev_register(dev, &priv->cdev);
I believe it'd be preferable to return the return value of this call.
> +}
> +
> +static int dell_privacy_acpi_probe(struct platform_device *pdev)
> +{
> + platform_set_drvdata(pdev, privacy_acpi);
> + privacy_acpi->dev = &pdev->dev;
> + privacy_acpi->platform_device = pdev;
> + return 0;
> +}
> +
> +static const struct acpi_device_id privacy_acpi_device_ids[] = {
> + {"PNP0C09", 0},
> + { },
> +};
> +MODULE_DEVICE_TABLE(acpi, privacy_acpi_device_ids);
> +
> +static struct platform_driver dell_privacy_platform_drv = {
> + .driver = {
> + .name = PRIVACY_PLATFORM_NAME,
> + .acpi_match_table = ACPI_PTR(privacy_acpi_device_ids),
> + },
> + .remove = dell_privacy_acpi_remove,
> +};
I think using a platform driver here just complicates things for no reason.
Furthermore, I'm not sure if there's actually any need for the ACPI match table.
> +
> +int dell_privacy_acpi_init(void)
I believe this could be marked __init.
> +{
> + int err;
> + struct platform_device *pdev;
> + int privacy_capable = wmi_has_guid(DELL_PRIVACY_GUID);
> +
> + if (!privacy_capable)
It could just be `if (!wmi_has_guid(...))`.
> + return -ENODEV;
> +
> + privacy_acpi = kzalloc(sizeof(struct privacy_acpi_priv), GFP_KERNEL);
Please use `sizeof(*privacy_acpi)`.
> + if (!privacy_acpi)
> + return -ENOMEM;
> +
> + pdev = platform_device_register_simple(
> + PRIVACY_PLATFORM_NAME, -1, NULL, 0);
Please use `PLATFORM_DEVID_NONE` instead of -1.
> + if (IS_ERR(pdev)) {
> + err = PTR_ERR(pdev);
> + goto pdev_err;
> + }
> + err = platform_driver_probe(&dell_privacy_platform_drv,
> + dell_privacy_acpi_probe);
What is the reason for preferring this instead of specifying the probe callback
in the platform_driver struct and registering it?
> + if (err)
> + goto pdrv_err;
> +
> + dell_privacy_leds_setup(&pdev->dev);
I think you should check if the call succeeds or not.
> +
> + return 0;
> +
> +pdrv_err:
> + platform_device_unregister(pdev);
> +pdev_err:
> + kfree(privacy_acpi);
> + return err;
> +}
> +
> +void dell_privacy_acpi_exit(void)
I believe this could be marked __exit.
> +{
> + 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-privacy-wmi.c b/drivers/platform/x86/dell-privacy-wmi.c
> new file mode 100644
> index 000000000000..80637c7f617c
> --- /dev/null
> +++ b/drivers/platform/x86/dell-privacy-wmi.c
> @@ -0,0 +1,309 @@
> +// 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)
> +
> +static int privacy_valid = -EPROBE_DEFER;
I think it'd be better `privacy_valid` was a `bool` (or maybe an enum):
```
enum dell_privacy_state {
DELL_PRIVACY_STATE_OK,
DELL_PRIVACY_STATE_NOK,
DELL_PRIVACY_STATE_UNKNOWN,
};
```
or something similar.
> +static LIST_HEAD(wmi_list);
> +static DEFINE_MUTEX(list_mutex);
> +
> +struct privacy_wmi_data {
> + struct input_dev *input_dev;
> + struct wmi_device *wdev;
> + struct list_head list;
> + 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 */
Any reason for "MIC" being capitalized?
> + { KE_KEY, 0x0001, { KEY_MICMUTE } },
> + /* Privacy Camera Mute */
> + { KE_SW, 0x0002, { SW_CAMERA_LENS_COVER } },
> + { KE_END, 0},
> +};
> +
> +int dell_privacy_valid(void)
> +{
> + int ret;
> +
> + ret = wmi_has_guid(DELL_PRIVACY_GUID);
> + if (!ret)
> + return -ENODEV;
> + ret = privacy_valid;
> + return ret;
I find this function really confusing, and too verbose for what it does.
> +}
> +EXPORT_SYMBOL_GPL(dell_privacy_valid);
> +
> +void dell_privacy_process_event(int type, int code, int status)
> +{
> + struct privacy_wmi_data *priv;
> + const struct key_entry *key;
> +
> + mutex_lock(&list_mutex);
> + priv = list_first_entry_or_null(&wmi_list,
> + struct privacy_wmi_data,
> + list);
Can you please explain why this list is needed if only the first entry will
ever be used?
> + 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);
> + break;
> + case DELL_PRIVACY_TYPE_CAMERA: /* Camera mute */
> + priv->last_status = status;
> + sparse_keymap_report_entry(priv->input_dev, key, 1, true);
> + break;
> + default:
> + dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x 0x%04x",
> + type, code);
> + }
Is this switch needed at all?
> +error:
> + mutex_unlock(&list_mutex);
> +}
> +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 sprintf(buf, "%d\n", priv->features_present);
Please use `sysfs_emit()`. And I believe printing with %x would be preferable.
> +}
> +
> +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 sprintf(buf, "%d\n", priv->last_status);
Same here.
> +}
> +
> +static DEVICE_ATTR_RO(devices_supported);
> +static DEVICE_ATTR_RO(current_state);
> +
> +static struct attribute *platform_attributes[] = {
Maybe "privacy_attributes" or something similar would be more expressive?
> + &dev_attr_devices_supported.attr,
> + &dev_attr_current_state.attr,
> + NULL,
> +};
> +
> +static const struct attribute_group privacy_attribute_group = {
> + .attrs = platform_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 = NULL;
As far as I see there is not need to initialize `obj_present`.
> + u32 *buffer;
> + int ret = 0;
> +
> + if (priv == NULL) {
Maybe `if (WARN_ON(!priv))`? But `!priv` is preferred in any case.
> + pr_err("dell privacy priv is NULL\n");
> + return -EINVAL;
> + }
> + /* check privacy support features and device states */
> + obj_present = wmidev_block_query(wdev, 0);
`wmidev_block_query()` may return `NULL`, so you should check for that as well.
> + if (obj_present->type != ACPI_TYPE_BUFFER) {
> + dev_err(&wdev->dev, "Dell privacy failed to get device status!\n");
I think a more specific error message ("unexpected type") would be preferable.
> + 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 = -ENODEV;
I personally don't think ENODEV is the most suitable error code here. EINVAL/EILSEQ
seem more appropriate to me.
> + privacy_valid = ret;
> + goto obj_free;
> + }
> + buffer = (u32 *)obj_present->buffer.pointer;
> + priv->features_present = buffer[0];
> + priv->last_status = buffer[1];
I believe `get_unaligned_{le,be}32()` from `asm/unaligned.h` would be preferable
here.
> + privacy_valid = 0;
> +
> +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, pos = 0;
There is actually no need for the `pos` variable.
> +
> + priv = devm_kzalloc(&wdev->dev, sizeof(struct privacy_wmi_data),
Please use `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) +
> + 1,
I don't think that `+ 1` is not needed since the KE_END entry is already in the array.
> + sizeof(struct key_entry), GFP_KERNEL);
> + if (!keymap) {
> + ret = -ENOMEM;
> + goto err_free_dev;
> + }
> + /* 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[pos] = dell_wmi_keymap_type_0012[i];
> + keymap[pos].code |= (0x0012 << 16);
> + pos++;
> + }
> + ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
> + if (ret)
> + return ret;
A copy of the keymap is created by `sparse_keymap_setup()`, so returning
here will leak `keymap`. You could just call `kfree(keymap)` directly after
the `sparse_keymap_setup()` call. But I find it completely unnecessary
to do this allocate-copy-modify thing. Is there any reason why the static array
(`dell_wmi_keymap_type_0012`) cannot already contain the correct values?
> + 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");
> + goto err_free_keymap;
> + }
> + mutex_lock(&list_mutex);
> + list_add_tail(&priv->list, &wmi_list);
> + mutex_unlock(&list_mutex);
> + if (get_current_status(priv->wdev))
> + goto err_free_keymap;
The input device is not unregistered in this branch.
> + ret = sysfs_create_group(&wdev->dev.kobj, &privacy_attribute_group);
I suggest you replace `sysfs_{create,remove}_group()` with
`device_{add,remove}_group()` as it is more expressive in my opinion.
> + if (ret)
> + goto err_free_keymap;
Similarly, the input device is not unregistered in this branch.
> + return 0;
`keymap` is again leaked by this return.
> +
> +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;
> + sysfs_remove_group(&wdev->dev.kobj, &privacy_attribute_group);
> +
The input device is not unregistered.
> + 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)
> + return -ENODEV;
The init function of a module that exports symbols must not fail, otherwise
it'll prevent the loading of dependent modules.
> +
> + ret = dell_privacy_acpi_init();
> + if (ret) {
> + pr_err("failed to initialize privacy acpi driver: %d\n", ret);
> + goto err_init;
> + }
> +
> + ret = wmi_driver_register(&dell_privacy_wmi_driver);
> + if (ret) {
> + pr_err("failed to initialize privacy wmi driver: %d\n", ret);
> + return ret;
> + }
> + return 0;
> +
> +err_init:
> + wmi_driver_unregister(&dell_privacy_wmi_driver);
At this point the WMI driver is not registered.
> + return ret;
> +}
> +
> +static void dell_privacy_wmi_exit(void)
I believe this function could be marked __exit as well.
> +{
> + 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);
> +
> +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-privacy-wmi.h b/drivers/platform/x86/dell-privacy-wmi.h
> new file mode 100644
> index 000000000000..9fa01d084f7d
> --- /dev/null
> +++ b/drivers/platform/x86/dell-privacy-wmi.h
> @@ -0,0 +1,33 @@
> +/* 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)
> +int dell_privacy_valid(void);
> +void dell_privacy_process_event(int type, int code, int status);
> +#else /* CONFIG_DELL_PRIVACY */
> +static inline int dell_privacy_valid(void)
> +{
> + return -ENODEV;
> +}
> +
> +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,
> +};
> +#endif
> diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
> index bbdb3e860892..4b22bd21fc42 100644
> --- a/drivers/platform/x86/dell-wmi.c
> +++ b/drivers/platform/x86/dell-wmi.c
> @@ -27,6 +27,7 @@
> #include <acpi/video.h>
> #include "dell-smbios.h"
> #include "dell-wmi-descriptor.h"
> +#include "dell-privacy-wmi.h"
>
> MODULE_AUTHOR("Matthew Garrett <mjg@xxxxxxxxxx>");
> MODULE_AUTHOR("Pali Rohár <pali@xxxxxxxxxx>");
> @@ -381,6 +382,7 @@ static void dell_wmi_notify(struct wmi_device *wdev,
> u16 *buffer_entry, *buffer_end;
> acpi_size buffer_size;
> int len, i;
> + int err;
>
> if (obj->type != ACPI_TYPE_BUFFER) {
> pr_warn("bad response type %x\n", obj->type);
> @@ -427,18 +429,30 @@ 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]);
> - /* Extended data is currently ignored */
> - break;
> case 0x0010: /* Sequence of keys pressed */
> case 0x0011: /* Sequence of events occurred */
> for (i = 2; i < len; ++i)
> dell_wmi_process_key(wdev, buffer_entry[1],
> buffer_entry[i]);
> break;
> + case 0x0012:
The comment "Event with extended data occurred" has been deleted.
> +#if IS_ENABLED(CONFIG_DELL_PRIVACY)
> + err = dell_privacy_valid();
> + if (err == 0) {
> + dell_privacy_process_event(buffer_entry[1],
> + buffer_entry[3], buffer_entry[4]);
What if `len < 5`?
> + } else {
> + if (len > 2)
> + dell_wmi_process_key(wdev, buffer_entry[1],
> + buffer_entry[2]);
> + }
> +#else
> + /* Extended data is currently ignored */
> + if (len > 2)
> + dell_wmi_process_key(wdev, buffer_entry[1],
> + buffer_entry[2]);
> +#endif
> + break;
> default: /* Unknown event */
> pr_info("Unknown WMI event type 0x%x\n",
> (int)buffer_entry[1]);
> --
> 2.25.1
Regards,
Barnabás Pőcze