// 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/bitops.h>
#include <linux/input.h>
#include <linux/input/sparse-keymap.h>
#include <linux/list.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/wmi.h>
#include "dell-wmi-privacy.h"
#define DELL_PRIVACY_GUID "6932965F-1671-4CEB-B988-D3AB0A901919"
#define MICROPHONE_STATUS BIT(0)
#define CAMERA_STATUS BIT(1)
#define DELL_PRIVACY_AUDIO_EVENT 0x1
#define DELL_PRIVACY_CAMERA_EVENT 0x2
#define led_to_priv(c) container_of(c, struct privacy_wmi_data, cdev)
/*
* The wmi_list is used to store the privacy_priv struct with mutex protecting
*/
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;
struct led_classdev cdev;
u32 features_present;
u32 last_status;
};
/* DELL Privacy Type */
enum dell_hardware_privacy_type {
DELL_PRIVACY_TYPE_AUDIO = 0,
DELL_PRIVACY_TYPE_CAMERA,
DELL_PRIVACY_TYPE_SCREEN,
DELL_PRIVACY_TYPE_MAX,
};
static const char * const privacy_types[DELL_PRIVACY_TYPE_MAX] = {
[DELL_PRIVACY_TYPE_AUDIO] = "Microphone",
[DELL_PRIVACY_TYPE_CAMERA] = "Camera Shutter",
[DELL_PRIVACY_TYPE_SCREEN] = "ePrivacy Screen",
};
/*
* 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_VSW, 0x0002, { SW_CAMERA_LENS_COVER } },
{ KE_END, 0},
};
bool dell_privacy_has_mic_mute(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 && (priv->features_present & BIT(DELL_PRIVACY_TYPE_AUDIO));
}
EXPORT_SYMBOL_GPL(dell_privacy_has_mic_mute);
/*
* 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 which will call
* led_set_brightness() on the LED registered by dell_privacy_leds_setup()
* 7) dell-privacy notifies EC, the timeout is cancelled and the HW mute activates.
* If the EC is not notified then the HW mic mute will activate when the timeout
* triggers, just a bit later than with the active ack.
*/
bool dell_privacy_process_event(int type, int code, int status)
{
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)
goto error;
key = sparse_keymap_entry_from_scancode(priv->input_dev, (type << 16) | code);
if (!key) {
dev_warn(&priv->wdev->dev, "Unknown key with type 0x%04x and code 0x%04x pressed\n",
type, code);
goto error;
}
dev_dbg(&priv->wdev->dev, "Key with type 0x%04x and code 0x%04x pressed\n", type, code);
switch (code) {
case DELL_PRIVACY_AUDIO_EVENT: /* Mic mute */
priv->last_status = status;
sparse_keymap_report_entry(priv->input_dev, key, 1, true);
ret = true;
break;
case DELL_PRIVACY_CAMERA_EVENT: /* Camera mute */
priv->last_status = status;
sparse_keymap_report_entry(priv->input_dev, key, !(status & CAMERA_STATUS), false);
ret = true;
break;
default:
dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x 0x%04x\n", type, code);
}
error:
mutex_unlock(&list_mutex);
return ret;
}
static ssize_t dell_privacy_supported_type_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct privacy_wmi_data *priv = dev_get_drvdata(dev);
enum dell_hardware_privacy_type type;
u32 privacy_list;
int len = 0;
privacy_list = priv->features_present;
for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX; type++) {
if (privacy_list & BIT(type))
len += sysfs_emit_at(buf, len, "[%s] [supported]\n", privacy_types[type]);
else
len += sysfs_emit_at(buf, len, "[%s] [unsupported]\n", privacy_types[type]);
}
return len;
}
static ssize_t dell_privacy_current_state_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct privacy_wmi_data *priv = dev_get_drvdata(dev);
u32 privacy_supported = priv->features_present;
enum dell_hardware_privacy_type type;
u32 privacy_state = priv->last_status;
int len = 0;
for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX; type++) {
if (privacy_supported & BIT(type)) {
if (privacy_state & BIT(type))
len += sysfs_emit_at(buf, len, "[%s] [unmuted]\n", privacy_types[type]);
else
len += sysfs_emit_at(buf, len, "[%s] [muted]\n", privacy_types[type]);
}
}
return len;
}
static DEVICE_ATTR_RO(dell_privacy_supported_type);
static DEVICE_ATTR_RO(dell_privacy_current_state);
static struct attribute *privacy_attrs[] = {
&dev_attr_dell_privacy_supported_type.attr,
&dev_attr_dell_privacy_current_state.attr,
NULL,
};
ATTRIBUTE_GROUPS(privacy);
/*
* 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) {
dev_err(&wdev->dev, "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");
return -EIO;
}
if (obj_present->type != ACPI_TYPE_BUFFER) {
dev_err(&wdev->dev, "Binary MOF is not a buffer!\n");
ret = -EIO;
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;
goto obj_free;
}
buffer = (u32 *)obj_present->buffer.pointer;
priv->features_present = buffer[0];
priv->last_status = buffer[1];
obj_free:
kfree(obj_present);
return ret;
}
static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
struct privacy_wmi_data *priv = led_to_priv(led_cdev);
static char *acpi_method = (char *)"ECAK";
acpi_status status;
acpi_handle handle;
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->wdev->dev, "Error setting privacy EC ack value: %s\n",
acpi_format_exception(status));
return -EIO;
}
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_wmi_data *priv = dev_get_drvdata(dev);
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";
return devm_led_classdev_register(dev, &priv->cdev);
}
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, j;
priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
dev_set_drvdata(&wdev->dev, priv);
priv->wdev = wdev;
ret = get_current_status(priv->wdev);
if (ret)
return ret;
/* 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)
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, j = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
/*
* Unlike keys where only presses matter, userspace may act
* on switches in both of their positions. Only register
* SW_CAMERA_LENS_COVER if it is actually there.
*/
if (dell_wmi_keymap_type_0012[i].type == KE_VSW &&
dell_wmi_keymap_type_0012[i].sw.code == SW_CAMERA_LENS_COVER &&
!(priv->features_present & BIT(DELL_PRIVACY_TYPE_CAMERA)))
continue;
keymap[j] = dell_wmi_keymap_type_0012[i];
keymap[j].code |= (0x0012 << 16);
j++;
}
ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
kfree(keymap);
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;
/* Report initial camera-cover status */
if (priv->features_present & BIT(DELL_PRIVACY_TYPE_CAMERA))
input_report_switch(priv->input_dev, SW_CAMERA_LENS_COVER,
!(priv->last_status & CAMERA_STATUS));
ret = input_register_device(priv->input_dev);
if (ret)
return ret;
if (priv->features_present & BIT(DELL_PRIVACY_TYPE_AUDIO)) {
ret = dell_privacy_leds_setup(&priv->wdev->dev);
if (ret)
return ret;
}
mutex_lock(&list_mutex);
list_add_tail(&priv->list, &wmi_list);
mutex_unlock(&list_mutex);
return 0;
}
static void 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);
}
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",
.dev_groups = privacy_groups,
},
.probe = dell_privacy_wmi_probe,
.remove = dell_privacy_wmi_remove,
.id_table = dell_wmi_privacy_wmi_id_table,
};
int dell_privacy_register_driver(void)
{
return wmi_driver_register(&dell_privacy_wmi_driver);
}
void dell_privacy_unregister_driver(void)
{
wmi_driver_unregister(&dell_privacy_wmi_driver);
}
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