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 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         { "", 0 },
 222 };
 223
 224 #ifdef CONFIG_PM_SLEEP
 225 static void ACPI_SYSTEM_XFACE rbtn_clear_suspended_flag(void *context)
 226 {
 227         struct rbtn_data *rbtn_data = context;
 228
 229         rbtn_data->suspended = false;
 230 }
 231
 232 static int rbtn_suspend(struct device *dev)
 233 {
 234         struct acpi_device *device = to_acpi_device(dev);
 235         struct rbtn_data *rbtn_data = acpi_driver_data(device);
 236
 237         rbtn_data->suspended = true;
 238
 239         return 0;
 240 }
 241
 242 static int rbtn_resume(struct device *dev)
 243 {
 244         struct acpi_device *device = to_acpi_device(dev);
 245         struct rbtn_data *rbtn_data = acpi_driver_data(device);
 246         acpi_status status;
 247
 248         /*
 249          * Upon resume, some BIOSes send an ACPI notification thet triggers
 250          * an unwanted input event. In order to ignore it, we use a flag
 251          * that we set at suspend and clear once we have received the extra
 252          * ACPI notification. Since ACPI notifications are delivered
 253          * asynchronously to drivers, we clear the flag from the workqueue
 254          * used to deliver the notifications. This should be enough
 255          * to have the flag cleared only after we received the extra
 256          * notification, if any.
 257          */
 258         status = acpi_os_execute(OSL_NOTIFY_HANDLER,
 259                          rbtn_clear_suspended_flag, rbtn_data);
 260         if (ACPI_FAILURE(status))
 261                 rbtn_clear_suspended_flag(rbtn_data);
 262
 263         return 0;
 264 }
 265 #endif
 266
 267 static SIMPLE_DEV_PM_OPS(rbtn_pm_ops, rbtn_suspend, rbtn_resume);
 268
 269 static struct acpi_driver rbtn_driver = {
 270         .name = "dell-rbtn",
 271         .ids = rbtn_ids,
 272         .drv.pm = &rbtn_pm_ops,
 273         .ops = {
 274                 .add = rbtn_add,
 275                 .remove = rbtn_remove,
 276                 .notify = rbtn_notify,
 277         },
 278         .owner = THIS_MODULE,
 279 };
 280
 281
 282 /*
 283  * notifier export functions
 284  */
 285
 286 static bool auto_remove_rfkill = true;
 287
 288 static ATOMIC_NOTIFIER_HEAD(rbtn_chain_head);
 289
 290 static int rbtn_inc_count(struct device *dev, void *data)
 291 {
 292         struct acpi_device *device = to_acpi_device(dev);
 293         struct rbtn_data *rbtn_data = device->driver_data;
 294         int *count = data;
 295
 296         if (rbtn_data->type == RBTN_SLIDER)
 297                 (*count)++;
 298
 299         return 0;
 300 }
 301
 302 static int rbtn_switch_dev(struct device *dev, void *data)
 303 {
 304         struct acpi_device *device = to_acpi_device(dev);
 305         struct rbtn_data *rbtn_data = device->driver_data;
 306         bool enable = data;
 307
 308         if (rbtn_data->type != RBTN_SLIDER)
 309                 return 0;
 310
 311         if (enable)
 312                 rbtn_rfkill_init(device);
 313         else
 314                 rbtn_rfkill_exit(device);
 315
 316         return 0;
 317 }
 318
 319 int dell_rbtn_notifier_register(struct notifier_block *nb)
 320 {
 321         bool first;
 322         int count;
 323         int ret;
 324
 325         count = 0;
 326         ret = driver_for_each_device(&rbtn_driver.drv, NULL, &count,
 327                                      rbtn_inc_count);
 328         if (ret || count == 0)
 329                 return -ENODEV;
 330
 331         first = !rbtn_chain_head.head;
 332
 333         ret = atomic_notifier_chain_register(&rbtn_chain_head, nb);
 334         if (ret != 0)
 335                 return ret;
 336
 337         if (auto_remove_rfkill && first)
 338                 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
 339                                              (void *)false, rbtn_switch_dev);
 340
 341         return ret;
 342 }
 343 EXPORT_SYMBOL_GPL(dell_rbtn_notifier_register);
 344
 345 int dell_rbtn_notifier_unregister(struct notifier_block *nb)
 346 {
 347         int ret;
 348
 349         ret = atomic_notifier_chain_unregister(&rbtn_chain_head, nb);
 350         if (ret != 0)
 351                 return ret;
 352
 353         if (auto_remove_rfkill && !rbtn_chain_head.head)
 354                 ret = driver_for_each_device(&rbtn_driver.drv, NULL,
 355                                              (void *)true, rbtn_switch_dev);
 356
 357         return ret;
 358 }
 359 EXPORT_SYMBOL_GPL(dell_rbtn_notifier_unregister);
 360
 361
 362 /*
 363  * acpi driver functions
 364  */
 365
 366 static int rbtn_add(struct acpi_device *device)
 367 {
 368         struct rbtn_data *rbtn_data;
 369         enum rbtn_type type;
 370         int ret = 0;
 371
 372         type = rbtn_check(device);
 373         if (type == RBTN_UNKNOWN) {
 374                 dev_info(&device->dev, "Unknown device type\n");
 375                 return -EINVAL;
 376         }
 377
 378         ret = rbtn_acquire(device, true);
 379         if (ret < 0) {
 380                 dev_err(&device->dev, "Cannot enable device\n");
 381                 return ret;
 382         }
 383
 384         rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
 385         if (!rbtn_data)
 386                 return -ENOMEM;
 387
 388         rbtn_data->type = type;
 389         device->driver_data = rbtn_data;
 390
 391         switch (rbtn_data->type) {
 392         case RBTN_TOGGLE:
 393                 ret = rbtn_input_init(rbtn_data);
 394                 break;
 395         case RBTN_SLIDER:
 396                 if (auto_remove_rfkill && rbtn_chain_head.head)
 397                         ret = 0;
 398                 else
 399                         ret = rbtn_rfkill_init(device);
 400                 break;
 401         default:
 402                 ret = -EINVAL;
 403         }
 404
 405         return ret;
 406
 407 }
 408
 409 static int rbtn_remove(struct acpi_device *device)
 410 {
 411         struct rbtn_data *rbtn_data = device->driver_data;
 412
 413         switch (rbtn_data->type) {
 414         case RBTN_TOGGLE:
 415                 rbtn_input_exit(rbtn_data);
 416                 break;
 417         case RBTN_SLIDER:
 418                 rbtn_rfkill_exit(device);
 419                 break;
 420         default:
 421                 break;
 422         }
 423
 424         rbtn_acquire(device, false);
 425         device->driver_data = NULL;
 426
 427         return 0;
 428 }
 429
 430 static void rbtn_notify(struct acpi_device *device, u32 event)
 431 {
 432         struct rbtn_data *rbtn_data = device->driver_data;
 433
 434         /*
 435          * Some BIOSes send a notification at resume.
 436          * Ignore it to prevent unwanted input events.
 437          */
 438         if (rbtn_data->suspended) {
 439                 dev_dbg(&device->dev, "ACPI notification ignored\n");
 440                 return;
 441         }
 442
 443         if (event != 0x80) {
 444                 dev_info(&device->dev, "Received unknown event (0x%x)\n",
 445                          event);
 446                 return;
 447         }
 448
 449         switch (rbtn_data->type) {
 450         case RBTN_TOGGLE:
 451                 rbtn_input_event(rbtn_data);
 452                 break;
 453         case RBTN_SLIDER:
 454                 rbtn_rfkill_event(device);
 455                 atomic_notifier_call_chain(&rbtn_chain_head, event, device);
 456                 break;
 457         default:
 458                 break;
 459         }
 460 }
 461
 462
 463 /*
 464  * module functions
 465  */
 466
 467 module_acpi_driver(rbtn_driver);
 468
 469 module_param(auto_remove_rfkill, bool, 0444);
 470
 471 MODULE_PARM_DESC(auto_remove_rfkill, "Automatically remove rfkill devices when "
 472                                      "other modules start receiving events "
 473                                      "from this module and re-add them when "
 474                                      "the last module stops receiving events "
 475                                      "(default true)");
 476 MODULE_DEVICE_TABLE(acpi, rbtn_ids);
 477 MODULE_DESCRIPTION("Dell Airplane Mode Switch driver");
 478 MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
 479 MODULE_LICENSE("GPL");