drivers/platform/x86/dell-rbtn.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3     Dell Airplane Mode Switch driver
   4     Copyright (C) 2014-2015  Pali Rohár <pali.rohar@gmail.com>
   5
   6 */
   7
   8 #include <linux/module.h>
   9 #include <linux/acpi.h>
  10 #include <linux/rfkill.h>
  11 #include <linux/input.h>
  12
  13 #include "dell-rbtn.h"
  14
  15 enum rbtn_type {
  16         RBTN_UNKNOWN,
  17         RBTN_TOGGLE,
  18         RBTN_SLIDER,
  19 };
  20
  21 struct rbtn_data {
  22         enum rbtn_type type;
  23         struct rfkill *rfkill;
  24         struct input_dev *input_dev;
  25         bool suspended;
  26 };
  27
  28
  29 /*
  30  * acpi functions
  31  */
  32
  33 static enum rbtn_type rbtn_check(struct acpi_device *device)
  34 {
  35         unsigned long long output;
  36         acpi_status status;
  37
  38         status = acpi_evaluate_integer(device->handle, "CRBT", NULL, &output);
  39         if (ACPI_FAILURE(status))
  40                 return RBTN_UNKNOWN;
  41
  42         switch (output) {
  43         case 0:
  44         case 1:
  45                 return RBTN_TOGGLE;
  46         case 2:
  47         case 3:
  48                 return RBTN_SLIDER;
  49         default:
  50                 return RBTN_UNKNOWN;
  51         }
  52 }
  53
  54 static int rbtn_get(struct acpi_device *device)
  55 {
  56         unsigned long long output;
  57         acpi_status status;
  58
  59         status = acpi_evaluate_integer(device->handle, "GRBT", NULL, &output);
  60         if (ACPI_FAILURE(status))
  61                 return -EINVAL;
  62
  63         return !output;
  64 }
  65
  66 static int rbtn_acquire(struct acpi_device *device, bool enable)
  67 {
  68         struct acpi_object_list input;
  69         union acpi_object param;
  70         acpi_status status;
  71
  72         param.type = ACPI_TYPE_INTEGER;
  73         param.integer.value = enable;
  74         input.count = 1;
  75         input.pointer = &param;
  76
  77         status = acpi_evaluate_object(device->handle, "ARBT", &input, NULL);
  78         if (ACPI_FAILURE(status))
  79                 return -EINVAL;
  80
  81         return 0;
  82 }
  83
  84
  85 /*
  86  * rfkill device
  87  */
  88
  89 static void rbtn_rfkill_query(struct rfkill *rfkill, void *data)
  90 {
  91         struct acpi_device *device = data;
  92         int state;
  93
  94         state = rbtn_get(device);
  95         if (state < 0)
  96                 return;
  97
  98         rfkill_set_states(rfkill, state, state);
  99 }
 100
 101 static int rbtn_rfkill_set_block(void *data, bool blocked)
 102 {
 103         /* NOTE: setting soft rfkill state is not supported */
 104         return -EINVAL;
 105 }
 106
 107 static const struct rfkill_ops rbtn_ops = {
 108         .query = rbtn_rfkill_query,
 109         .set_block = rbtn_rfkill_set_block,
 110 };
 111
 112 static int rbtn_rfkill_init(struct acpi_device *device)
 113 {
 114         struct rbtn_data *rbtn_data = device->driver_data;
 115         int ret;
 116
 117         if (rbtn_data->rfkill)
 118                 return 0;
 119
 120         /*
 121          * NOTE: rbtn controls all radio devices, not only WLAN
 122          *       but rfkill interface does not support "ANY" type
 123          *       so "WLAN" type is used
 124          */
 125         rbtn_data->rfkill = rfkill_alloc("dell-rbtn", &device->dev,
 126                                          RFKILL_TYPE_WLAN, &rbtn_ops, device);
 127         if (!rbtn_data->rfkill)
 128                 return -ENOMEM;
 129
 130         ret = rfkill_register(rbtn_data->rfkill);
 131         if (ret) {
 132                 rfkill_destroy(rbtn_data->rfkill);
 133                 rbtn_data->rfkill = NULL;
 134                 return ret;
 135         }
 136
 137         return 0;
 138 }
 139
 140 static void rbtn_rfkill_exit(struct acpi_device *device)
 141 {
 142         struct rbtn_data *rbtn_data = device->driver_data;
 143
 144         if (!rbtn_data->rfkill)
 145                 return;
 146
 147         rfkill_unregister(rbtn_data->rfkill);
 148         rfkill_destroy(rbtn_data->rfkill);
 149         rbtn_data->rfkill = NULL;
 150 }
 151
 152 static void rbtn_rfkill_event(struct acpi_device *device)
 153 {
 154         struct rbtn_data *rbtn_data = device->driver_data;
 155
 156         if (rbtn_data->rfkill)
 157                 rbtn_rfkill_query(rbtn_data->rfkill, device);
 158 }
 159
 160
 161 /*
 162  * input device
 163  */
 164
 165 static int rbtn_input_init(struct rbtn_data *rbtn_data)
 166 {
 167         int ret;
 168
 169         rbtn_data->input_dev = input_allocate_device();
 170         if (!rbtn_data->input_dev)
 171                 return -ENOMEM;
 172
 173         rbtn_data->input_dev->name = "DELL Wireless hotkeys";
 174         rbtn_data->input_dev->phys = "dellabce/input0";
 175         rbtn_data->input_dev->id.bustype = BUS_HOST;
 176         rbtn_data->input_dev->evbit[0] = BIT(EV_KEY);
 177         set_bit(KEY_RFKILL, rbtn_data->input_dev->keybit);
 178
 179         ret = input_register_device(rbtn_data->input_dev);
 180         if (ret) {
 181                 input_free_device(rbtn_data->input_dev);
 182                 rbtn_data->input_dev = NULL;
 183                 return ret;
 184         }
 185
 186         return 0;
 187 }
 188
 189 static void rbtn_input_exit(struct rbtn_data *rbtn_data)
 190 {
 191         input_unregister_device(rbtn_data->input_dev);
 192         rbtn_data->input_dev = NULL;
 193 }
 194
 195 static void rbtn_input_event(struct rbtn_data *rbtn_data)
 196 {
 197         input_report_key(rbtn_data->input_dev, KEY_RFKILL, 1);
 198         input_sync(rbtn_data->input_dev);
 199         input_report_key(rbtn_data->input_dev, KEY_RFKILL, 0);
 200         input_sync(rbtn_data->input_dev);
 201 }
 202
 203
 204 /*
 205  * acpi driver
 206  */
 207
 208 static int rbtn_add(struct acpi_device *device);
 209 static int rbtn_remove(struct acpi_device *device);
 210 static void rbtn_notify(struct acpi_device *device, u32 event);
 211
 212 static const struct acpi_device_id rbtn_ids[] = {
 213         { "DELRBTN", 0 },
 214         { "DELLABCE", 0 },
 215
 216         /*
 217          * This driver can also handle the "DELLABC6" device that
 218          * appears on the XPS 13 9350, but that device is disabled by
 219          * the DSDT unless booted with acpi_osi="!Windows 2012"
 220          * acpi_osi="!Windows 2013".
 221          *
 222          * According to Mario at Dell:
 223          *
 224          *  DELLABC6 is a custom interface that was created solely to
 225          *  have airplane mode support for Windows 7.  For Windows 10
 226          *  the proper interface is to use that which is handled by
 227          *  intel-hid. A OEM airplane mode driver is not used.
 228          *
 229          *  Since the kernel doesn't identify as Windows 7 it would be
 230          *  incorrect to do attempt to use that interface.
 231          *
 232          * Even if we override _OSI and bind to DELLABC6, we end up with
 233          * inconsistent behavior in which userspace can get out of sync
 234          * with the rfkill state as it conflicts with events from
 235          * intel-hid.
 236          *
 237          * The upshot is that it is better to just ignore DELLABC6
 238          * devices.
 239          */
 240
 241         { "", 0 },
 242 };
 243
 244 #ifdef CONFIG_PM_SLEEP
 245 static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
 246 {
 247         struct rbtn_data *rbtn_data = context;
 248
 249         rbtn_data->suspended = false;
 250 }
 251
 252 static int rbtn_suspend(struct device *dev)
 253 {
 254         struct acpi_device *device = to_acpi_device(dev);
 255         struct rbtn_data *rbtn_data = acpi_driver_data(device);
 256
 257         rbtn_data->suspended = true;
 258
 259         return 0;
 260 }
 261
 262 static int rbtn_resume(struct device *dev)
 263 {
 264         struct acpi_device *device = to_acpi_device(dev);
 265         struct rbtn_data *rbtn_data = acpi_driver_data(device);
 266         acpi_status status;
 267
 268         /*
 269          * Upon resume, some BIOSes send an ACPI notification thet triggers
 270          * an unwanted input event. In order to ignore it, we use a flag
 271          * that we set at suspend and clear once we have received the extra
 272          * ACPI notification. Since ACPI notifications are delivered
 273          * asynchronously to drivers, we clear the flag from the workqueue
 274          * used to deliver the notifications. This should be enough
 275          * to have the flag cleared only after we received the extra
 276          * notification, if any.
 277          */
 278         status = acpi_os_execute(OSL_NOTIFY_HANDLER,
 279                          rbtn_clear_suspended_flag, rbtn_data);
 280         if (ACPI_FAILURE(status))
 281                 rbtn_clear_suspended_flag(rbtn_data);
 282
 283         return 0;
 284 }
 285 #endif
 286
 287 static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
 288
 289 static struct acpi_driver rbtn_driver = {
 290         .name = "dell-rbtn",
 291         .ids = rbtn_ids,
 292         .drv.pm = &rbtn_pm_ops,
 293         .ops = {
 294                 .add = rbtn_add,
 295                 .remove = rbtn_remove,
 296                 .notify = rbtn_notify,
 297         },
 298         .owner = THIS_MODULE,
 299 };
 300
 301
 302 /*
 303  * notifier export functions
 304  */
 305
 306 static bool auto_remove_rfkill = true;
 307
 308 static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
 309
 310 static int rbtn_inc_count(struct device *dev, void *data)
 311 {
 312         struct acpi_device *device = to_acpi_device(dev);
 313         struct rbtn_data *rbtn_data = device->driver_data;
 314         int *count = data;
 315
 316         if (rbtn_data->type == RBTN_SLIDER)
 317                 (*count)++;
 318
 319         return 0;
 320 }
 321
 322 static int rbtn_switch_dev(struct device *dev, void *data)
 323 {
 324         struct acpi_device *device = to_acpi_device(dev);
 325         struct rbtn_data *rbtn_data = device->driver_data;
 326         bool enable = data;
 327
 328         if (rbtn_data->type != RBTN_SLIDER)
 329                 return 0;
 330
 331         if (enable)
 332                 rbtn_rfkill_init(device);
 333         else
 334                 rbtn_rfkill_exit(device);
 335
 336         return 0;
 337 }
 338
 339 int dell_rbtn_notifier_register(struct notifier_block *nb)
 340 {
 341         bool first;
 342         int count;
 343         int ret;
 344
 345         count = 0;
 346         ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
 347                                      rbtn_inc_count);
 348         if (ret || count == 0)
 349                 return -ENODEV;
 350
 351         first = !rbtn_chain_head.head;
 352
 353         ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
 354         if (ret != 0)
 355                 return ret;
 356
 357         if (auto_remove_rfkill && first)
 358                 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
 359                                              (void *)false, rbtn_switch_dev);
 360
 361         return ret;
 362 }
 363 EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
 364
 365 int dell_rbtn_notifier_unregister(struct notifier_block *nb)
 366 {
 367         int ret;
 368
 369         ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
 370         if (ret != 0)
 371                 return ret;
 372
 373         if (auto_remove_rfkill && !rbtn_chain_head.head)
 374                 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
 375                                              (void *)true, rbtn_switch_dev);
 376
 377         return ret;
 378 }
 379 EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
 380
 381
 382 /*
 383  * acpi driver functions
 384  */
 385
 386 static int rbtn_add(struct acpi_device *device)
 387 {
 388         struct rbtn_data *rbtn_data;
 389         enum rbtn_type type;
 390         int ret = 0;
 391
 392         type = rbtn_check(device);
 393         if (type == RBTN_UNKNOWN) {
 394                 dev_info(&device->dev, "Unknown device type\n");
 395                 return -EINVAL;
 396         }
 397
 398         ret = rbtn_acquire(device, true);
 399         if (ret < 0) {
 400                 dev_err(&device->dev, "Cannot enable device\n");
 401                 return ret;
 402         }
 403
 404         rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
 405         if (!rbtn_data)
 406                 return -ENOMEM;
 407
 408         rbtn_data->type = type;
 409         device->driver_data = rbtn_data;
 410
 411         switch (rbtn_data->type) {
 412         case RBTN_TOGGLE:
 413                 ret = rbtn_input_init(rbtn_data);
 414                 break;
 415         case RBTN_SLIDER:
 416                 if (auto_remove_rfkill && rbtn_chain_head.head)
 417                         ret = 0;
 418                 else
 419                         ret = rbtn_rfkill_init(device);
 420                 break;
 421         default:
 422                 ret = -EINVAL;
 423         }
 424
 425         return ret;
 426
 427 }
 428
 429 static int rbtn_remove(struct acpi_device *device)
 430 {
 431         struct rbtn_data *rbtn_data = device->driver_data;
 432
 433         switch (rbtn_data->type) {
 434         case RBTN_TOGGLE:
 435                 rbtn_input_exit(rbtn_data);
 436                 break;
 437         case RBTN_SLIDER:
 438                 rbtn_rfkill_exit(device);
 439                 break;
 440         default:
 441                 break;
 442         }
 443
 444         rbtn_acquire(device, false);
 445         device->driver_data = NULL;
 446
 447         return 0;
 448 }
 449
 450 static void rbtn_notify(struct acpi_device *device, u32 event)
 451 {
 452         struct rbtn_data *rbtn_data = device->driver_data;
 453
 454         /*
 455          * Some BIOSes send a notification at resume.
 456          * Ignore it to prevent unwanted input events.
 457          */
 458         if (rbtn_data->suspended) {
 459                 dev_dbg(&device->dev, "ACPI notification ignored\n");
 460                 return;
 461         }
 462
 463         if (event != 0x80) {
 464                 dev_info(&device->dev, "Received unknown event (0x%x)\n",
 465                          event);
 466                 return;
 467         }
 468
 469         switch (rbtn_data->type) {
 470         case RBTN_TOGGLE:
 471                 rbtn_input_event(rbtn_data);
 472                 break;
 473         case RBTN_SLIDER:
 474                 rbtn_rfkill_event(device);
 475                 atomic_notifier_call_chain(&rbtn_chain_head, event, device);
 476                 break;
 477         default:
 478                 break;
 479         }
 480 }
 481
 482
 483 /*
 484  * module functions
 485  */
 486
 487 module_acpi_driver(rbtn_driver);
 488
 489 module_param(auto_remove_rfkill, bool, 0444);
 490
 491 MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
 492                                      "other modules start receiving events "
 493                                      "from this module and re-add them when "
 494                                      "the last module stops receiving events "
 495                                      "(default true)");
 496 MODULE_DEVICE_TABLE(acpi, rbtn_ids);
 497 MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
 498 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 499 MODULE_LICENSE("GPL");