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_VSW, 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 priv->last_status = status;
119 sparse_keymap_report_entry(priv->input_dev, key, 1, true);
120 ret = true;
121 break;
122 case DELL_PRIVACY_CAMERA_EVENT: /* Camera mute */
123 priv->last_status = status;
124 sparse_keymap_report_entry(priv->input_dev, key, !(status & CAMERA_STATUS), false);
125 ret = true;
126 break;
127 default:
128 dev_dbg(&priv->wdev->dev, "unknown event type 0x%04x 0x%04x\n", type, code);
129 }
130
131 error:
132 mutex_unlock(&list_mutex);
133 return ret;
134 }
135
dell_privacy_supported_type_show(struct device * dev,struct device_attribute * attr,char * buf)136 static ssize_t dell_privacy_supported_type_show(struct device *dev,
137 struct device_attribute *attr,
138 char *buf)
139 {
140 struct privacy_wmi_data *priv = dev_get_drvdata(dev);
141 enum dell_hardware_privacy_type type;
142 u32 privacy_list;
143 int len = 0;
144
145 privacy_list = priv->features_present;
146 for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX; type++) {
147 if (privacy_list & BIT(type))
148 len += sysfs_emit_at(buf, len, "[%s] [supported]\n", privacy_types[type]);
149 else
150 len += sysfs_emit_at(buf, len, "[%s] [unsupported]\n", privacy_types[type]);
151 }
152
153 return len;
154 }
155
dell_privacy_current_state_show(struct device * dev,struct device_attribute * attr,char * buf)156 static ssize_t dell_privacy_current_state_show(struct device *dev,
157 struct device_attribute *attr,
158 char *buf)
159 {
160 struct privacy_wmi_data *priv = dev_get_drvdata(dev);
161 u32 privacy_supported = priv->features_present;
162 enum dell_hardware_privacy_type type;
163 u32 privacy_state = priv->last_status;
164 int len = 0;
165
166 for (type = DELL_PRIVACY_TYPE_AUDIO; type < DELL_PRIVACY_TYPE_MAX; type++) {
167 if (privacy_supported & BIT(type)) {
168 if (privacy_state & BIT(type))
169 len += sysfs_emit_at(buf, len, "[%s] [unmuted]\n", privacy_types[type]);
170 else
171 len += sysfs_emit_at(buf, len, "[%s] [muted]\n", privacy_types[type]);
172 }
173 }
174
175 return len;
176 }
177
178 static DEVICE_ATTR_RO(dell_privacy_supported_type);
179 static DEVICE_ATTR_RO(dell_privacy_current_state);
180
181 static struct attribute *privacy_attributes[] = {
182 &dev_attr_dell_privacy_supported_type.attr,
183 &dev_attr_dell_privacy_current_state.attr,
184 NULL,
185 };
186
187 static const struct attribute_group privacy_attribute_group = {
188 .attrs = privacy_attributes
189 };
190
191 /*
192 * Describes the Device State class exposed by BIOS which can be consumed by
193 * various applications interested in knowing the Privacy feature capabilities.
194 * class DeviceState
195 * {
196 * [key, read] string InstanceName;
197 * [read] boolean ReadOnly;
198 *
199 * [WmiDataId(1), read] uint32 DevicesSupported;
200 * 0 - None; 0x1 - Microphone; 0x2 - Camera; 0x4 - ePrivacy Screen
201 *
202 * [WmiDataId(2), read] uint32 CurrentState;
203 * 0 - Off; 1 - On; Bit0 - Microphone; Bit1 - Camera; Bit2 - ePrivacyScreen
204 * };
205 */
get_current_status(struct wmi_device * wdev)206 static int get_current_status(struct wmi_device *wdev)
207 {
208 struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
209 union acpi_object *obj_present;
210 u32 *buffer;
211 int ret = 0;
212
213 if (!priv) {
214 dev_err(&wdev->dev, "dell privacy priv is NULL\n");
215 return -EINVAL;
216 }
217 /* check privacy support features and device states */
218 obj_present = wmidev_block_query(wdev, 0);
219 if (!obj_present) {
220 dev_err(&wdev->dev, "failed to read Binary MOF\n");
221 return -EIO;
222 }
223
224 if (obj_present->type != ACPI_TYPE_BUFFER) {
225 dev_err(&wdev->dev, "Binary MOF is not a buffer!\n");
226 ret = -EIO;
227 goto obj_free;
228 }
229 /* Although it's not technically a failure, this would lead to
230 * unexpected behavior
231 */
232 if (obj_present->buffer.length != 8) {
233 dev_err(&wdev->dev, "Dell privacy buffer has unexpected length (%d)!\n",
234 obj_present->buffer.length);
235 ret = -EINVAL;
236 goto obj_free;
237 }
238 buffer = (u32 *)obj_present->buffer.pointer;
239 priv->features_present = buffer[0];
240 priv->last_status = buffer[1];
241
242 obj_free:
243 kfree(obj_present);
244 return ret;
245 }
246
dell_privacy_micmute_led_set(struct led_classdev * led_cdev,enum led_brightness brightness)247 static int dell_privacy_micmute_led_set(struct led_classdev *led_cdev,
248 enum led_brightness brightness)
249 {
250 struct privacy_wmi_data *priv = led_to_priv(led_cdev);
251 static char *acpi_method = (char *)"ECAK";
252 acpi_status status;
253 acpi_handle handle;
254
255 handle = ec_get_handle();
256 if (!handle)
257 return -EIO;
258
259 if (!acpi_has_method(handle, acpi_method))
260 return -EIO;
261
262 status = acpi_evaluate_object(handle, acpi_method, NULL, NULL);
263 if (ACPI_FAILURE(status)) {
264 dev_err(&priv->wdev->dev, "Error setting privacy EC ack value: %s\n",
265 acpi_format_exception(status));
266 return -EIO;
267 }
268
269 return 0;
270 }
271
272 /*
273 * Pressing the mute key activates a time delayed circuit to physically cut
274 * off the mute. The LED is in the same circuit, so it reflects the true
275 * state of the HW mute. The reason for the EC "ack" is so that software
276 * can first invoke a SW mute before the HW circuit is cut off. Without SW
277 * cutting this off first does not affect the time delayed muting or status
278 * of the LED but there is a possibility of a "popping" noise.
279 *
280 * If the EC receives the SW ack, the circuit will be activated before the
281 * delay completed.
282 *
283 * Exposing as an LED device allows the codec drivers notification path to
284 * EC ACK to work
285 */
dell_privacy_leds_setup(struct device * dev)286 static int dell_privacy_leds_setup(struct device *dev)
287 {
288 struct privacy_wmi_data *priv = dev_get_drvdata(dev);
289
290 priv->cdev.name = "dell-privacy::micmute";
291 priv->cdev.max_brightness = 1;
292 priv->cdev.brightness_set_blocking = dell_privacy_micmute_led_set;
293 priv->cdev.default_trigger = "audio-micmute";
294 priv->cdev.brightness = ledtrig_audio_get(LED_AUDIO_MICMUTE);
295 return devm_led_classdev_register(dev, &priv->cdev);
296 }
297
dell_privacy_wmi_probe(struct wmi_device * wdev,const void * context)298 static int dell_privacy_wmi_probe(struct wmi_device *wdev, const void *context)
299 {
300 struct privacy_wmi_data *priv;
301 struct key_entry *keymap;
302 int ret, i, j;
303
304 ret = wmi_has_guid(DELL_PRIVACY_GUID);
305 if (!ret)
306 pr_debug("Unable to detect available Dell privacy devices!\n");
307
308 priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
309 if (!priv)
310 return -ENOMEM;
311
312 dev_set_drvdata(&wdev->dev, priv);
313 priv->wdev = wdev;
314
315 ret = get_current_status(priv->wdev);
316 if (ret)
317 return ret;
318
319 /* create evdev passing interface */
320 priv->input_dev = devm_input_allocate_device(&wdev->dev);
321 if (!priv->input_dev)
322 return -ENOMEM;
323
324 /* remap the wmi keymap event to new keymap */
325 keymap = kcalloc(ARRAY_SIZE(dell_wmi_keymap_type_0012),
326 sizeof(struct key_entry), GFP_KERNEL);
327 if (!keymap)
328 return -ENOMEM;
329
330 /* remap the keymap code with Dell privacy key type 0x12 as prefix
331 * KEY_MICMUTE scancode will be reported as 0x120001
332 */
333 for (i = 0, j = 0; i < ARRAY_SIZE(dell_wmi_keymap_type_0012); i++) {
334 /*
335 * Unlike keys where only presses matter, userspace may act
336 * on switches in both of their positions. Only register
337 * SW_CAMERA_LENS_COVER if it is actually there.
338 */
339 if (dell_wmi_keymap_type_0012[i].type == KE_VSW &&
340 dell_wmi_keymap_type_0012[i].sw.code == SW_CAMERA_LENS_COVER &&
341 !(priv->features_present & BIT(DELL_PRIVACY_TYPE_CAMERA)))
342 continue;
343
344 keymap[j] = dell_wmi_keymap_type_0012[i];
345 keymap[j].code |= (0x0012 << 16);
346 j++;
347 }
348 ret = sparse_keymap_setup(priv->input_dev, keymap, NULL);
349 kfree(keymap);
350 if (ret)
351 return ret;
352
353 priv->input_dev->dev.parent = &wdev->dev;
354 priv->input_dev->name = "Dell Privacy Driver";
355 priv->input_dev->id.bustype = BUS_HOST;
356
357 /* Report initial camera-cover status */
358 if (priv->features_present & BIT(DELL_PRIVACY_TYPE_CAMERA))
359 input_report_switch(priv->input_dev, SW_CAMERA_LENS_COVER,
360 !(priv->last_status & CAMERA_STATUS));
361
362 ret = input_register_device(priv->input_dev);
363 if (ret)
364 return ret;
365
366 ret = devm_device_add_group(&wdev->dev, &privacy_attribute_group);
367 if (ret)
368 return ret;
369
370 if (priv->features_present & BIT(DELL_PRIVACY_TYPE_AUDIO)) {
371 ret = dell_privacy_leds_setup(&priv->wdev->dev);
372 if (ret)
373 return ret;
374 }
375 mutex_lock(&list_mutex);
376 list_add_tail(&priv->list, &wmi_list);
377 mutex_unlock(&list_mutex);
378 return 0;
379 }
380
dell_privacy_wmi_remove(struct wmi_device * wdev)381 static void dell_privacy_wmi_remove(struct wmi_device *wdev)
382 {
383 struct privacy_wmi_data *priv = dev_get_drvdata(&wdev->dev);
384
385 mutex_lock(&list_mutex);
386 list_del(&priv->list);
387 mutex_unlock(&list_mutex);
388 }
389
390 static const struct wmi_device_id dell_wmi_privacy_wmi_id_table[] = {
391 { .guid_string = DELL_PRIVACY_GUID },
392 { },
393 };
394
395 static struct wmi_driver dell_privacy_wmi_driver = {
396 .driver = {
397 .name = "dell-privacy",
398 },
399 .probe = dell_privacy_wmi_probe,
400 .remove = dell_privacy_wmi_remove,
401 .id_table = dell_wmi_privacy_wmi_id_table,
402 };
403
dell_privacy_register_driver(void)404 int dell_privacy_register_driver(void)
405 {
406 return wmi_driver_register(&dell_privacy_wmi_driver);
407 }
408
dell_privacy_unregister_driver(void)409 void dell_privacy_unregister_driver(void)
410 {
411 wmi_driver_unregister(&dell_privacy_wmi_driver);
412 }
413