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SubjectRe: [PATCH v3 1/3] platform/x86: dell-privacy: Add support for Dell hardware privacy
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On 1/12/21 11:17 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
> 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(embedded controller)
> and camera mute hotkey is ctrl+f9. currently design only emmit
> SW_CAMERA_LENS_COVER event while the camera lens shutter will be
> changed by EC & hw(hadware) control

It wouldn't hurt to use capital letters and punctuation, it helps with
readility..

[...]

> diff --git a/drivers/platform/x86/dell-laptop.c b/drivers/platform/x86/dell-laptop.c
> index 70edc5bb3a14..2fea1f34fcf9 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;

why is this variable needed? Was the intent to have a kernel parameter here?

> module_param(force_rfkill, bool, 0444);
> MODULE_PARM_DESC(force_rfkill, "enable rfkill on non whitelisted models");
> @@ -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) {

if it was intended to be used as a kernel parameter it's not done the
right way: the value set by the user would be ignored...

> + 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..df6a86e1345c
> --- /dev/null
> +++ b/drivers/platform/x86/dell-privacy-acpi.c
> @@ -0,0 +1,167 @@
> +// 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;
> + acpi_status status;
> + acpi_handle handle;
> + char *acpi_method;
> +
> + handle = ec_get_handle();
> + if (!handle)
> + return -EIO;
> + acpi_method = "ECAK";
> + 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);
> +
> + 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 < 0)
> + return ret;
> + return 0;
> +}
> +
> +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),
> + },

no .probe?

> + .remove = dell_privacy_acpi_remove,
> +};
> +
> +int __init dell_privacy_acpi_init(void)
> +{
> + int err;
> + struct platform_device *pdev;
> + int privacy_capable = wmi_has_guid(DELL_PRIVACY_GUID);
> +
> + if (!wmi_has_guid(DELL_PRIVACY_GUID))
> + return -ENODEV;
> +
> + privacy_acpi = kzalloc(sizeof(*privacy_acpi), GFP_KERNEL);
> + if (!privacy_acpi)
> + return -ENOMEM;
> +
> + pdev = platform_device_register_simple(
> + PRIVACY_PLATFORM_NAME, PLATFORM_DEVID_NONE, NULL, 0);
> + if (IS_ERR(pdev)) {
> + err = PTR_ERR(pdev);
> + goto pdev_err;
> + }
> + err = platform_driver_probe(&dell_privacy_platform_drv,
> + dell_privacy_acpi_probe);
> + if (err)
> + goto pdrv_err;

why is the probe done here? Put differently, what prevents you from
using a 'normal' platform driver, and do the leds_setup in the .probe()?

> +
> + err = dell_privacy_leds_setup(&pdev->dev);
> + if (err < 0)
> + goto pdrv_err;
> +
> + return 0;
> +
> +pdrv_err:
> + platform_device_unregister(pdev);
> +pdev_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-privacy-wmi.c b/drivers/platform/x86/dell-privacy-wmi.c
> new file mode 100644
> index 000000000000..432a3f4ed226
> --- /dev/null
> +++ b/drivers/platform/x86/dell-privacy-wmi.c
> @@ -0,0 +1,320 @@
> +// 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;

this is set to -ENODEV on remove. that looks odd to me.

> +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 */
> + { 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;

return privacy_valid?

> +}
> +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);
> + if (!priv) {
> + pr_err("dell privacy priv is NULL\n");
> + goto error;
> + }
> + key = sparse_keymap_entry_from_scancode(priv->input_dev, (type << 16)|code);

missing spaces, does this even pass with checkpatch.pl?

> + 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 */

Never seen anyone 'mute' their camera? 'switch off' or 'disable'?

> + 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);
> + }
> +error:
> + mutex_unlock(&list_mutex);
> +}
> +EXPORT_SYMBOL_GPL(dell_privacy_process_event);

[...]

> +/*
> + * 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;
> + }

can this happen? when would this pointer be NULL?

> + /* 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;
> +
> +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;
> +
> + 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) +
> + 1,

same line?

> + 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;
> + 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_input;
> + ret = devm_device_add_group(&wdev->dev, &privacy_attribute_group);
> + if (ret)
> + goto err_free_input;
> + kfree(keymap);
> + return 0;

having a set of newlines wouldn't hurt, thsi is not very easy to read
and split in logical sections...

> +
> +err_free_input:
> + input_unregister_device(priv->input_dev);
> +err_free_keymap:
> + privacy_valid = -ENODEV;
> + kfree(keymap);
> +err_free_dev:
> + input_free_device(priv->input_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);
> +
> + return 0;
> +}

[...]

> + case 0x0012:
> +#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]);
> + } else {
> + if (len > 2)
> + dell_wmi_process_key(wdev, buffer_entry[1],
> + buffer_entry[2]);
> + /* Extended data is currently ignored */
> + }
> +#else
> + if (len > 2)
> + dell_wmi_process_key(wdev, buffer_entry[1],
> + buffer_entry[2]);
> + /* Extended data is currently ignored */
> +#endif

this doesn't look very nice, can we avoid the duplication?

> + break;
> default: /* Unknown event */
> pr_info("Unknown WMI event type 0x%x\n",
> (int)buffer_entry[1]);
>

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