drivers/platform/x86/dell-rbtn.c

   1 /*
   2     Dell Airplane Mode Switch driver
   3     Copyright (C) 2014-2015  Pali Rohár <pali.rohar@gmail.com>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14 */
  15
  16 #include <linux/module.h>
  17 #include <linux/acpi.h>
  18 #include <linux/rfkill.h>
  19 #include <linux/input.h>
  20
  21 enum rbtn_type {
  22         RBTN_UNKNOWN,
  23         RBTN_TOGGLE,
  24         RBTN_SLIDER,
  25 };
  26
  27 struct rbtn_data {
  28         enum rbtn_type type;
  29         struct rfkill *rfkill;
  30         struct input_dev *input_dev;
  31         bool suspended;
  32 };
  33
  34
  35 /*
  36  * acpi functions
  37  */
  38
  39 static enum rbtn_type rbtn_check(struct acpi_device *device)
  40 {
  41         unsigned long long output;
  42         acpi_status status;
  43
  44         status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
  45         if (ACPI_FAILURE(status))
  46                 return RBTN_UNKNOWN;
  47
  48         switch (output) {
  49         case 0:
  50         case 1:
  51                 return RBTN_TOGGLE;
  52         case 2:
  53         case 3:
  54                 return RBTN_SLIDER;
  55         default:
  56                 return RBTN_UNKNOWN;
  57         }
  58 }
  59
  60 static int rbtn_get(struct acpi_device *device)
  61 {
  62         unsigned long long output;
  63         acpi_status status;
  64
  65         status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
  66         if (ACPI_FAILURE(status))
  67                 return -EINVAL;
  68
  69         return !output;
  70 }
  71
  72 static int rbtn_acquire(struct acpi_device *device, bool enable)
  73 {
  74         struct acpi_object_list input;
  75         union acpi_object param;
  76         acpi_status status;
  77
  78         param.type = ACPI_TYPE_INTEGER;
  79         param.integer.value = enable;
  80         input.count = 1;
  81         input.pointer = &param;
  82
  83         status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
  84         if (ACPI_FAILURE(status))
  85                 return -EINVAL;
  86
  87         return 0;
  88 }
  89
  90
  91 /*
  92  * rfkill device
  93  */
  94
  95 static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
  96 {
  97         struct acpi_device *device = data;
  98         int state;
  99
 100         state = rbtn_get(device);
 101         if (state < 0)
 102                 return;
 103
 104         rfkill_set_states(rfkill, state, state);
 105 }
 106
 107 static int rbtn_rfkill_set_block(void *data, bool blocked)
 108 {
 109         /* NOTE: setting soft rfkill state is not supported */
 110         return -EINVAL;
 111 }
 112
 113 static const struct rfkill_ops rbtn_ops = {
 114         .query = rbtn_rfkill_query,
 115         .set_block = rbtn_rfkill_set_block,
 116 };
 117
 118 static int rbtn_rfkill_init(struct acpi_device *device)
 119 {
 120         struct rbtn_data *rbtn_data = device->driver_data;
 121         int ret;
 122
 123         if (rbtn_data->rfkill)
 124                 return 0;
 125
 126         /*
 127          * NOTE: rbtn controls all radio devices, not only WLAN
 128          *       but rfkill interface does not support "ANY" type
 129          *       so "WLAN" type is used
 130          */
 131         rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
 132                                          RFKILL_TYPE_WLAN, &rbtn_ops, device);
 133         if (!rbtn_data->rfkill)
 134                 return -ENOMEM;
 135
 136         ret = rfkill_register(rbtn_data->rfkill);
 137         if (ret) {
 138                 rfkill_destroy(rbtn_data->rfkill);
 139                 rbtn_data->rfkill = NULL;
 140                 return ret;
 141         }
 142
 143         return 0;
 144 }
 145
 146 static void rbtn_rfkill_exit(struct acpi_device *device)
 147 {
 148         struct rbtn_data *rbtn_data = device->driver_data;
 149
 150         if (!rbtn_data->rfkill)
 151                 return;
 152
 153         rfkill_unregister(rbtn_data->rfkill);
 154         rfkill_destroy(rbtn_data->rfkill);
 155         rbtn_data->rfkill = NULL;
 156 }
 157
 158 static void rbtn_rfkill_event(struct acpi_device *device)
 159 {
 160         struct rbtn_data *rbtn_data = device->driver_data;
 161
 162         if (rbtn_data->rfkill)
 163                 rbtn_rfkill_query(rbtn_data->rfkill, device);
 164 }
 165
 166
 167 /*
 168  * input device
 169  */
 170
 171 static int rbtn_input_init(struct rbtn_data *rbtn_data)
 172 {
 173         int ret;
 174
 175         rbtn_data->input_dev = input_allocate_device();
 176         if (!rbtn_data->input_dev)
 177                 return -ENOMEM;
 178
 179         rbtn_data->input_dev->name = "DELL Wireless hotkeys";
 180         rbtn_data->input_dev->phys = "dellabce/input0";
 181         rbtn_data->input_dev->id.bustype = BUS_HOST;
 182         rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
 183         set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);
 184
 185         ret = input_register_device(rbtn_data->input_dev);
 186         if (ret) {
 187                 input_free_device(rbtn_data->input_dev);
 188                 rbtn_data->input_dev = NULL;
 189                 return ret;
 190         }
 191
 192         return 0;
 193 }
 194
 195 static void rbtn_input_exit(struct rbtn_data *rbtn_data)
 196 {
 197         input_unregister_device(rbtn_data->input_dev);
 198         rbtn_data->input_dev = NULL;
 199 }
 200
 201 static void rbtn_input_event(struct rbtn_data *rbtn_data)
 202 {
 203         input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
 204         input_sync(rbtn_data->input_dev);
 205         input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
 206         input_sync(rbtn_data->input_dev);
 207 }
 208
 209
 210 /*
 211  * acpi driver
 212  */
 213
 214 static int rbtn_add(struct acpi_device *device);
 215 static int rbtn_remove(struct acpi_device *device);
 216 static void rbtn_notify(struct acpi_device *device, u32 event);
 217
 218 static const struct acpi_device_id rbtn_ids[] = {
 219         { "DELRBTN", 0 },
 220         { "DELLABCE", 0 },
 221
 222         /*
 223          * This driver can also handle the "DELLABC6" device that
 224          * appears on the XPS 13 9350, but that device is disabled by
 225          * the DSDT unless booted with acpi_osi="!Windows 2012"
 226          * acpi_osi="!Windows 2013".
 227          *
 228          * According to Mario at Dell:
 229          *
 230          *  DELLABC6 is a custom interface that was created solely to
 231          *  have airplane mode support for Windows 7.  For Windows 10
 232          *  the proper interface is to use that which is handled by
 233          *  intel-hid. A OEM airplane mode driver is not used.
 234          *
 235          *  Since the kernel doesn't identify as Windows 7 it would be
 236          *  incorrect to do attempt to use that interface.
 237          *
 238          * Even if we override _OSI and bind to DELLABC6, we end up with
 239          * inconsistent behavior in which userspace can get out of sync
 240          * with the rfkill state as it conflicts with events from
 241          * intel-hid.
 242          *
 243          * The upshot is that it is better to just ignore DELLABC6
 244          * devices.
 245          */
 246
 247         { "", 0 },
 248 };
 249
 250 #ifdef CONFIG_PM_SLEEP
 251 static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
 252 {
 253         struct rbtn_data *rbtn_data = context;
 254
 255         rbtn_data->suspended = false;
 256 }
 257
 258 static int rbtn_suspend(struct device *dev)
 259 {
 260         struct acpi_device *device = to_acpi_device(dev);
 261         struct rbtn_data *rbtn_data = acpi_driver_data(device);
 262
 263         rbtn_data->suspended = true;
 264
 265         return 0;
 266 }
 267
 268 static int rbtn_resume(struct device *dev)
 269 {
 270         struct acpi_device *device = to_acpi_device(dev);
 271         struct rbtn_data *rbtn_data = acpi_driver_data(device);
 272         acpi_status status;
 273
 274         /*
 275          * Upon resume, some BIOSes send an ACPI notification thet triggers
 276          * an unwanted input event. In order to ignore it, we use a flag
 277          * that we set at suspend and clear once we have received the extra
 278          * ACPI notification. Since ACPI notifications are delivered
 279          * asynchronously to drivers, we clear the flag from the workqueue
 280          * used to deliver the notifications. This should be enough
 281          * to have the flag cleared only after we received the extra
 282          * notification, if any.
 283          */
 284         status = acpi_os_execute(OSL_NOTIFY_HANDLER,
 285                          rbtn_clear_suspended_flag, rbtn_data);
 286         if (ACPI_FAILURE(status))
 287                 rbtn_clear_suspended_flag(rbtn_data);
 288
 289         return 0;
 290 }
 291 #endif
 292
 293 static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
 294
 295 static struct acpi_driver rbtn_driver = {
 296         .name = "dell-rbtn",
 297         .ids = rbtn_ids,
 298         .drv.pm = &rbtn_pm_ops,
 299         .ops = {
 300                 .add = rbtn_add,
 301                 .remove = rbtn_remove,
 302                 .notify = rbtn_notify,
 303         },
 304         .owner = THIS_MODULE,
 305 };
 306
 307
 308 /*
 309  * notifier export functions
 310  */
 311
 312 static bool auto_remove_rfkill = true;
 313
 314 static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
 315
 316 static int rbtn_inc_count(struct device *dev, void *data)
 317 {
 318         struct acpi_device *device = to_acpi_device(dev);
 319         struct rbtn_data *rbtn_data = device->driver_data;
 320         int *count = data;
 321
 322         if (rbtn_data->type == RBTN_SLIDER)
 323                 (*count)++;
 324
 325         return 0;
 326 }
 327
 328 static int rbtn_switch_dev(struct device *dev, void *data)
 329 {
 330         struct acpi_device *device = to_acpi_device(dev);
 331         struct rbtn_data *rbtn_data = device->driver_data;
 332         bool enable = data;
 333
 334         if (rbtn_data->type != RBTN_SLIDER)
 335                 return 0;
 336
 337         if (enable)
 338                 rbtn_rfkill_init(device);
 339         else
 340                 rbtn_rfkill_exit(device);
 341
 342         return 0;
 343 }
 344
 345 int dell_rbtn_notifier_register(struct notifier_block *nb)
 346 {
 347         bool first;
 348         int count;
 349         int ret;
 350
 351         count = 0;
 352         ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
 353                                      rbtn_inc_count);
 354         if (ret || count == 0)
 355                 return -ENODEV;
 356
 357         first = !rbtn_chain_head.head;
 358
 359         ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
 360         if (ret != 0)
 361                 return ret;
 362
 363         if (auto_remove_rfkill && first)
 364                 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
 365                                              (void *)false, rbtn_switch_dev);
 366
 367         return ret;
 368 }
 369 EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
 370
 371 int dell_rbtn_notifier_unregister(struct notifier_block *nb)
 372 {
 373         int ret;
 374
 375         ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
 376         if (ret != 0)
 377                 return ret;
 378
 379         if (auto_remove_rfkill && !rbtn_chain_head.head)
 380                 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
 381                                              (void *)true, rbtn_switch_dev);
 382
 383         return ret;
 384 }
 385 EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
 386
 387
 388 /*
 389  * acpi driver functions
 390  */
 391
 392 static int rbtn_add(struct acpi_device *device)
 393 {
 394         struct rbtn_data *rbtn_data;
 395         enum rbtn_type type;
 396         int ret = 0;
 397
 398         type = rbtn_check(device);
 399         if (type == RBTN_UNKNOWN) {
 400                 dev_info(&device->dev, "Unknown device type\n");
 401                 return -EINVAL;
 402         }
 403
 404         ret = rbtn_acquire(device, true);
 405         if (ret < 0) {
 406                 dev_err(&device->dev, "Cannot enable device\n");
 407                 return ret;
 408         }
 409
 410         rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
 411         if (!rbtn_data)
 412                 return -ENOMEM;
 413
 414         rbtn_data->type = type;
 415         device->driver_data = rbtn_data;
 416
 417         switch (rbtn_data->type) {
 418         case RBTN_TOGGLE:
 419                 ret = rbtn_input_init(rbtn_data);
 420                 break;
 421         case RBTN_SLIDER:
 422                 if (auto_remove_rfkill && rbtn_chain_head.head)
 423                         ret = 0;
 424                 else
 425                         ret = rbtn_rfkill_init(device);
 426                 break;
 427         default:
 428                 ret = -EINVAL;
 429         }
 430
 431         return ret;
 432
 433 }
 434
 435 static int rbtn_remove(struct acpi_device *device)
 436 {
 437         struct rbtn_data *rbtn_data = device->driver_data;
 438
 439         switch (rbtn_data->type) {
 440         case RBTN_TOGGLE:
 441                 rbtn_input_exit(rbtn_data);
 442                 break;
 443         case RBTN_SLIDER:
 444                 rbtn_rfkill_exit(device);
 445                 break;
 446         default:
 447                 break;
 448         }
 449
 450         rbtn_acquire(device, false);
 451         device->driver_data = NULL;
 452
 453         return 0;
 454 }
 455
 456 static void rbtn_notify(struct acpi_device *device, u32 event)
 457 {
 458         struct rbtn_data *rbtn_data = device->driver_data;
 459
 460         /*
 461          * Some BIOSes send a notification at resume.
 462          * Ignore it to prevent unwanted input events.
 463          */
 464         if (rbtn_data->suspended) {
 465                 dev_dbg(&device->dev, "ACPI notification ignored\n");
 466                 return;
 467         }
 468
 469         if (event != 0x80) {
 470                 dev_info(&device->dev, "Received unknown event (0x%x)\n",
 471                          event);
 472                 return;
 473         }
 474
 475         switch (rbtn_data->type) {
 476         case RBTN_TOGGLE:
 477                 rbtn_input_event(rbtn_data);
 478                 break;
 479         case RBTN_SLIDER:
 480                 rbtn_rfkill_event(device);
 481                 atomic_notifier_call_chain(&rbtn_chain_head, event, device);
 482                 break;
 483         default:
 484                 break;
 485         }
 486 }
 487
 488
 489 /*
 490  * module functions
 491  */
 492
 493 module_acpi_driver(rbtn_driver);
 494
 495 module_param(auto_remove_rfkill, bool, 0444);
 496
 497 MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
 498                                      "other modules start receiving events "
 499                                      "from this module and re-add them when "
 500                                      "the last module stops receiving events "
 501                                      "(default true)");
 502 MODULE_DEVICE_TABLE(acpi, rbtn_ids);
 503 MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
 504 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 505 MODULE_LICENSE("GPL");