1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Dell privacy notification driver
4 *
5 * Copyright (C) 2021 Dell Inc. All Rights Reserved.
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/acpi.h>
11 #include <linux/bitops.h>
12 #include <linux/input.h>
13 #include <linux/input/sparse-keymap.h>
14 #include <linux/list.h>
15 #include <linux/leds.h>
16 #include <linux/module.h>
17 #include <linux/wmi.h>
18
19 #include "dell-wmi-privacy.h"
20
21 #define DELL_PRIVACY_GUID "6932965F-1671-4CEB-B988-D3AB0A901919"
22 #define MICROPHONE_STATUS BIT(0)
23 #define CAMERA_STATUS BIT(1)
24 #define DELL_PRIVACY_AUDIO_EVENT 0x1
25 #define DELL_PRIVACY_CAMERA_EVENT 0x2
26 #define led_to_priv(c) container_of(c, struct privacy_wmi_data, cdev)
27
28 /*
29 * The wmi_list is used to store the privacy_priv struct with mutex protecting
30 */
31 static LIST_HEAD(wmi_list);
32 static DEFINE_MUTEX(list_mutex);
33
34 struct privacy_wmi_data {
35 struct input_dev *input_dev;
36 struct wmi_device *wdev;
37 struct list_head list;
38 struct led_classdev cdev;
39 u32 features_present;
40 u32 last_status;
41 };
42
43 /* DELL Privacy Type */
44 enum dell_hardware_privacy_type {
45 DELL_PRIVACY_TYPE_AUDIO = 0,
46 DELL_PRIVACY_TYPE_CAMERA,
47 DELL_PRIVACY_TYPE_SCREEN,
48 DELL_PRIVACY_TYPE_MAX,
49 };
50
51 static const char * const privacy_types[DELL_PRIVACY_TYPE_MAX] = {
52 [DELL_PRIVACY_TYPE_AUDIO] = "Microphone",
53 [DELL_PRIVACY_TYPE_CAMERA] = "Camera Shutter",
54 [DELL_PRIVACY_TYPE_SCREEN] = "ePrivacy Screen",
55 };
56
57 /*
58 * Keymap for WMI privacy events of type 0x0012
59 */
60 static const struct key_entry dell_wmi_keymap_type_0012[] = {
61 /* privacy mic mute */
62 { KE_KEY, 0x0001, { KEY_MICMUTE } },
63 /* privacy camera mute */
64 { KE_SW, 0x0002, { SW_CAMERA_LENS_COVER } },
65 { KE_END, 0},
66 };
67
dell_privacy_has_mic_mute(void)68 bool dell_privacy_has_mic_mute(void)
69 {
70 struct privacy_wmi_data *priv;
71
72 mutex_lock(&list_mutex);
73 priv = list_first_entry_or_null(&wmi_list,
74 struct privacy_wmi_data,
75 list);
76 mutex_unlock(&list_mutex);
77
78 return priv && (priv->features_present & BIT(DELL_PRIVACY_TYPE_AUDIO));
79 }
80 EXPORT_SYMBOL_GPL(dell_privacy_has_mic_mute);
81
82 /*
83 * The flow of privacy event:
84 * 1) User presses key. HW does stuff with this key (timeout is started)
85 * 2) WMI event is emitted from BIOS
86 * 3) WMI event is received by dell-privacy
87 * 4) KEY_MICMUTE emitted from dell-privacy
88 * 5) Userland picks up key and modifies kcontrol for SW mute
89 * 6) Codec kernel driver catches and calls ledtrig_audio_set which will call
90 * led_set_brightness() on the LED registered by dell_privacy_leds_setup()
91 * 7) dell-privacy notifies EC, the timeout is cancelled and the HW mute activates.
92 * If the EC is not notified then the HW mic mute will activate when the timeout
93 * triggers, just a bit later than with the active ack.
94 */
dell_privacy_process_event(int type,int code,int status)95 bool dell_privacy_process_event(int type, int code, int status)
96 {
97 struct privacy_wmi_data *priv;
98 const struct key_entry *key;
99 bool ret = false;
100
101 mutex_lock(&list_mutex);
102 priv = list_first_entry_or_null(&wmi_list,
103 struct privacy_wmi_data,
104 list);
105 if (!priv)
106 goto error;
107
108 key = sparse_keymap_entry_from_scancode(priv->input_dev, (type << 16) | code);
109 if (!key) {
110 dev_warn(&priv->wdev->dev, "Unknown key with type 0x%04x and code 0x%04x pressed\n",
111 type, code);
112 goto error;
113 }
114 dev_dbg(&priv->wdev->dev, "Key with type 0x%04x and code 0x%04x pressed\n", type, code);
115
116 switch (code) {
117 case DELL_PRIVACY_AUDIO_EVENT: /* Mic mute */
118 case DELL_PRIVACY_CAMERA_EVENT: /* Camera mute */
119 priv->last_status = status;
120 sparse_keymap_report_entry(priv->input_dev, key, 1, true);
121 ret = true;
122 break;
123 default:
124 dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x 0x%04x\n", type, code);
125 }
126
127 error:
128 mutex_unlock(&list_mutex);
129 return ret;
130 }
131
dell_privacy_supported_type_show(struct device * dev,struct device_attribute * attr,char * buf)132 static ssize_t dell_privacy_supported_type_show(struct device *dev,
133 struct device_attribute *attr,
134 char *buf)
135 {
136 struct privacy_wmi_data *priv = dev_get_drvdata(dev);
137 enum dell_hardware_privacy_type type;
138 u32 privacy_list;
139 int len = 0;
140
141 privacy_list = priv->features_present;
142 for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX; type++) {
143 if (privacy_list & BIT(type))
144 len += sysfs_emit_at(buf, len, "[%s] [supported]\n", privacy_types[type]);
145 else
146 len += sysfs_emit_at(buf, len, "[%s] [unsupported]\n", privacy_types[type]);
147 }
148
149 return len;
150 }
151
dell_privacy_current_state_show(struct device * dev,struct device_attribute * attr,char * buf)152 static ssize_t dell_privacy_current_state_show(struct device *dev,
153 struct device_attribute *attr,
154 char *buf)
155 {
156 struct privacy_wmi_data *priv = dev_get_drvdata(dev);
157 u32 privacy_supported = priv->features_present;
158 enum dell_hardware_privacy_type type;
159 u32 privacy_state = priv->last_status;
160 int len = 0;
161
162 for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX; type++) {
163 if (privacy_supported & BIT(type)) {
164 if (privacy_state & BIT(type))
165 len += sysfs_emit_at(buf, len, "[%s] [unmuted]\n", privacy_types[type]);
166 else
167 len += sysfs_emit_at(buf, len, "[%s] [muted]\n", privacy_types[type]);
168 }
169 }
170
171 return len;
172 }
173
174 static DEVICE_ATTR_RO(dell_privacy_supported_type);
175 static DEVICE_ATTR_RO(dell_privacy_current_state);
176
177 static struct attribute *privacy_attrs[] = {
178 &dev_attr_dell_privacy_supported_type.attr,
179 &dev_attr_dell_privacy_current_state.attr,
180 NULL,
181 };
182 ATTRIBUTE_GROUPS(privacy);
183
184 /*
185 * Describes the Device State class exposed by BIOS which can be consumed by
186 * various applications interested in knowing the Privacy feature capabilities.
187 * class DeviceState
188 * {
189 * [key, read] string InstanceName;
190 * [read] boolean ReadOnly;
191 *
192 * [WmiDataId(1), read] uint32 DevicesSupported;
193 * 0 - None; 0x1 - Microphone; 0x2 - Camera; 0x4 - ePrivacy Screen
194 *
195 * [WmiDataId(2), read] uint32 CurrentState;
196 * 0 - Off; 1 - On; Bit0 - Microphone; Bit1 - Camera; Bit2 - ePrivacyScreen
197 * };
198 */
get_current_status(struct wmi_device * wdev)199 static int get_current_status(struct wmi_device *wdev)
200 {
201 struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
202 union acpi_object *obj_present;
203 u32 *buffer;
204 int ret = 0;
205
206 if (!priv) {
207 dev_err(&wdev->dev, "dell privacy priv is NULL\n");
208 return -EINVAL;
209 }
210 /* check privacy support features and device states */
211 obj_present = wmidev_block_query(wdev, 0);
212 if (!obj_present) {
213 dev_err(&wdev->dev, "failed to read Binary MOF\n");
214 return -EIO;
215 }
216
217 if (obj_present->type != ACPI_TYPE_BUFFER) {
218 dev_err(&wdev->dev, "Binary MOF is not a buffer!\n");
219 ret = -EIO;
220 goto obj_free;
221 }
222 /* Although it's not technically a failure, this would lead to
223 * unexpected behavior
224 */
225 if (obj_present->buffer.length != 8) {
226 dev_err(&wdev->dev, "Dell privacy buffer has unexpected length (%d)!\n",
227 obj_present->buffer.length);
228 ret = -EINVAL;
229 goto obj_free;
230 }
231 buffer = (u32 *)obj_present->buffer.pointer;
232 priv->features_present = buffer[0];
233 priv->last_status = buffer[1];
234
235 obj_free:
236 kfree(obj_present);
237 return ret;
238 }
239
dell_privacy_micmute_led_set(struct led_classdev * led_cdev,enum led_brightness brightness)240 static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
241 enum led_brightness brightness)
242 {
243 struct privacy_wmi_data *priv = led_to_priv(led_cdev);
244 static char *acpi_method = (char *)"ECAK";
245 acpi_status status;
246 acpi_handle handle;
247
248 handle = ec_get_handle();
249 if (!handle)
250 return -EIO;
251
252 if (!acpi_has_method(handle, acpi_method))
253 return -EIO;
254
255 status = acpi_evaluate_object(handle, acpi_method, NULL, NULL);
256 if (ACPI_FAILURE(status)) {
257 dev_err(&priv->wdev->dev, "Error setting privacy EC ack value: %s\n",
258 acpi_format_exception(status));
259 return -EIO;
260 }
261
262 return 0;
263 }
264
265 /*
266 * Pressing the mute key activates a time delayed circuit to physically cut
267 * off the mute. The LED is in the same circuit, so it reflects the true
268 * state of the HW mute. The reason for the EC "ack" is so that software
269 * can first invoke a SW mute before the HW circuit is cut off. Without SW
270 * cutting this off first does not affect the time delayed muting or status
271 * of the LED but there is a possibility of a "popping" noise.
272 *
273 * If the EC receives the SW ack, the circuit will be activated before the
274 * delay completed.
275 *
276 * Exposing as an LED device allows the codec drivers notification path to
277 * EC ACK to work
278 */
dell_privacy_leds_setup(struct device * dev)279 static int dell_privacy_leds_setup(struct device *dev)
280 {
281 struct privacy_wmi_data *priv = dev_get_drvdata(dev);
282
283 priv->cdev.name = "dell-privacy::micmute";
284 priv->cdev.max_brightness = 1;
285 priv->cdev.brightness_set_blocking = dell_privacy_micmute_led_set;
286 priv->cdev.default_trigger = "audio-micmute";
287 priv->cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
288 return devm_led_classdev_register(dev, &priv->cdev);
289 }
290
dell_privacy_wmi_probe(struct wmi_device * wdev,const void * context)291 static int dell_privacy_wmi_probe(struct wmi_device *wdev, const void *context)
292 {
293 struct privacy_wmi_data *priv;
294 struct key_entry *keymap;
295 int ret, i;
296
297 ret = wmi_has_guid(DELL_PRIVACY_GUID);
298 if (!ret)
299 pr_debug("Unable to detect available Dell privacy devices!\n");
300
301 priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
302 if (!priv)
303 return -ENOMEM;
304
305 dev_set_drvdata(&wdev->dev, priv);
306 priv->wdev = wdev;
307 /* create evdev passing interface */
308 priv->input_dev = devm_input_allocate_device(&wdev->dev);
309 if (!priv->input_dev)
310 return -ENOMEM;
311
312 /* remap the wmi keymap event to new keymap */
313 keymap = kcalloc(ARRAY_SIZE(dell_wmi_keymap_type_0012),
314 sizeof(struct key_entry), GFP_KERNEL);
315 if (!keymap)
316 return -ENOMEM;
317
318 /* remap the keymap code with Dell privacy key type 0x12 as prefix
319 * KEY_MICMUTE scancode will be reported as 0x120001
320 */
321 for (i = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
322 keymap[i] = dell_wmi_keymap_type_0012[i];
323 keymap[i].code |= (0x0012 << 16);
324 }
325 ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
326 kfree(keymap);
327 if (ret)
328 return ret;
329
330 priv->input_dev->dev.parent = &wdev->dev;
331 priv->input_dev->name = "Dell Privacy Driver";
332 priv->input_dev->id.bustype = BUS_HOST;
333
334 ret = input_register_device(priv->input_dev);
335 if (ret)
336 return ret;
337
338 ret = get_current_status(priv->wdev);
339 if (ret)
340 return ret;
341
342 if (priv->features_present & BIT(DELL_PRIVACY_TYPE_AUDIO)) {
343 ret = dell_privacy_leds_setup(&priv->wdev->dev);
344 if (ret)
345 return ret;
346 }
347 mutex_lock(&list_mutex);
348 list_add_tail(&priv->list, &wmi_list);
349 mutex_unlock(&list_mutex);
350 return 0;
351 }
352
dell_privacy_wmi_remove(struct wmi_device * wdev)353 static void dell_privacy_wmi_remove(struct wmi_device *wdev)
354 {
355 struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
356
357 mutex_lock(&list_mutex);
358 list_del(&priv->list);
359 mutex_unlock(&list_mutex);
360 }
361
362 static const struct wmi_device_id dell_wmi_privacy_wmi_id_table[] = {
363 { .guid_string = DELL_PRIVACY_GUID },
364 { },
365 };
366
367 static struct wmi_driver dell_privacy_wmi_driver = {
368 .driver = {
369 .name = "dell-privacy",
370 .dev_groups = privacy_groups,
371 },
372 .probe = dell_privacy_wmi_probe,
373 .remove = dell_privacy_wmi_remove,
374 .id_table = dell_wmi_privacy_wmi_id_table,
375 };
376
dell_privacy_register_driver(void)377 int dell_privacy_register_driver(void)
378 {
379 return wmi_driver_register(&dell_privacy_wmi_driver);
380 }
381
dell_privacy_unregister_driver(void)382 void dell_privacy_unregister_driver(void)
383 {
384 wmi_driver_unregister(&dell_privacy_wmi_driver);
385 }
386
