drivers/acpi/button.c

   1 /*
   2  *  button.c - ACPI Button Driver
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *
   7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or (at
  12  *  your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful, but
  15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  *  General Public License for more details.
  18  *
  19  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  20  */
  21
  22 #define pr_fmt(fmt) "ACPI: button: " fmt
  23
  24 #include <linux/compiler.h>
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/init.h>
  28 #include <linux/types.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/seq_file.h>
  31 #include <linux/input.h>
  32 #include <linux/slab.h>
  33 #include <linux/acpi.h>
  34 #include <linux/dmi.h>
  35 #include <acpi/button.h>
  36
  37 #define PREFIX "ACPI: "
  38
  39 #define ACPI_BUTTON_CLASS               "button"
  40 #define ACPI_BUTTON_FILE_INFO           "info"
  41 #define ACPI_BUTTON_FILE_STATE          "state"
  42 #define ACPI_BUTTON_TYPE_UNKNOWN        0x00
  43 #define ACPI_BUTTON_NOTIFY_STATUS       0x80
  44
  45 #define ACPI_BUTTON_SUBCLASS_POWER      "power"
  46 #define ACPI_BUTTON_HID_POWER           "PNP0C0C"
  47 #define ACPI_BUTTON_DEVICE_NAME_POWER   "Power Button"
  48 #define ACPI_BUTTON_TYPE_POWER          0x01
  49
  50 #define ACPI_BUTTON_SUBCLASS_SLEEP      "sleep"
  51 #define ACPI_BUTTON_HID_SLEEP           "PNP0C0E"
  52 #define ACPI_BUTTON_DEVICE_NAME_SLEEP   "Sleep Button"
  53 #define ACPI_BUTTON_TYPE_SLEEP          0x03
  54
  55 #define ACPI_BUTTON_SUBCLASS_LID        "lid"
  56 #define ACPI_BUTTON_HID_LID             "PNP0C0D"
  57 #define ACPI_BUTTON_DEVICE_NAME_LID     "Lid Switch"
  58 #define ACPI_BUTTON_TYPE_LID            0x05
  59
  60 #define ACPI_BUTTON_LID_INIT_IGNORE     0x00
  61 #define ACPI_BUTTON_LID_INIT_OPEN       0x01
  62 #define ACPI_BUTTON_LID_INIT_METHOD     0x02
  63
  64 #define _COMPONENT              ACPI_BUTTON_COMPONENT
  65 ACPI_MODULE_NAME("button");
  66
  67 MODULE_AUTHOR("Paul Diefenbaugh");
  68 MODULE_DESCRIPTION("ACPI Button Driver");
  69 MODULE_LICENSE("GPL");
  70
  71 static const struct acpi_device_id button_device_ids[] = {
  72         {ACPI_BUTTON_HID_LID,    0},
  73         {ACPI_BUTTON_HID_SLEEP,  0},
  74         {ACPI_BUTTON_HID_SLEEPF, 0},
  75         {ACPI_BUTTON_HID_POWER,  0},
  76         {ACPI_BUTTON_HID_POWERF, 0},
  77         {"", 0},
  78 };
  79 MODULE_DEVICE_TABLE(acpi, button_device_ids);
  80
  81 /*
  82  * Some devices which don't even have a lid in anyway have a broken _LID
  83  * method (e.g. pointing to a floating gpio pin) causing spurious LID events.
  84  */
  85 static const struct dmi_system_id lid_blacklst[] = {
  86         {
  87                 /* GP-electronic T701 */
  88                 .matches = {
  89                         DMI_MATCH(DMI_SYS_VENDOR, "Insyde"),
  90                         DMI_MATCH(DMI_PRODUCT_NAME, "T701"),
  91                         DMI_MATCH(DMI_BIOS_VERSION, "BYT70A.YNCHENG.WIN.007"),
  92                 },
  93         },
  94         {}
  95 };
  96
  97 static int acpi_button_add(struct acpi_device *device);
  98 static int acpi_button_remove(struct acpi_device *device);
  99 static void acpi_button_notify(struct acpi_device *device, u32 event);
 100
 101 #ifdef CONFIG_PM_SLEEP
 102 static int acpi_button_suspend(struct device *dev);
 103 static int acpi_button_resume(struct device *dev);
 104 #else
 105 #define acpi_button_suspend NULL
 106 #define acpi_button_resume NULL
 107 #endif
 108 static SIMPLE_DEV_PM_OPS(acpi_button_pm, acpi_button_suspend, acpi_button_resume);
 109
 110 static struct acpi_driver acpi_button_driver = {
 111         .name = "button",
 112         .class = ACPI_BUTTON_CLASS,
 113         .ids = button_device_ids,
 114         .ops = {
 115                 .add = acpi_button_add,
 116                 .remove = acpi_button_remove,
 117                 .notify = acpi_button_notify,
 118         },
 119         .drv.pm = &acpi_button_pm,
 120 };
 121
 122 struct acpi_button {
 123         unsigned int type;
 124         struct input_dev *input;
 125         char phys[32];                  /* for input device */
 126         unsigned long pushed;
 127         int last_state;
 128         ktime_t last_time;
 129         bool suspended;
 130 };
 131
 132 static BLOCKING_NOTIFIER_HEAD(acpi_lid_notifier);
 133 static struct acpi_device *lid_device;
 134 static u8 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
 135
 136 static unsigned long lid_report_interval __read_mostly = 500;
 137 module_param(lid_report_interval, ulong, 0644);
 138 MODULE_PARM_DESC(lid_report_interval, "Interval (ms) between lid key events");
 139
 140 /* --------------------------------------------------------------------------
 141                               FS Interface (/proc)
 142    -------------------------------------------------------------------------- */
 143
 144 static struct proc_dir_entry *acpi_button_dir;
 145 static struct proc_dir_entry *acpi_lid_dir;
 146
 147 static int acpi_lid_evaluate_state(struct acpi_device *device)
 148 {
 149         unsigned long long lid_state;
 150         acpi_status status;
 151
 152         status = acpi_evaluate_integer(device->handle, "_LID", NULL, &lid_state);
 153         if (ACPI_FAILURE(status))
 154                 return -ENODEV;
 155
 156         return lid_state ? 1 : 0;
 157 }
 158
 159 static int acpi_lid_notify_state(struct acpi_device *device, int state)
 160 {
 161         struct acpi_button *button = acpi_driver_data(device);
 162         int ret;
 163         ktime_t next_report;
 164         bool do_update;
 165
 166         /*
 167          * In lid_init_state=ignore mode, if user opens/closes lid
 168          * frequently with "open" missing, and "last_time" is also updated
 169          * frequently, "close" cannot be delivered to the userspace.
 170          * So "last_time" is only updated after a timeout or an actual
 171          * switch.
 172          */
 173         if (lid_init_state != ACPI_BUTTON_LID_INIT_IGNORE ||
 174             button->last_state != !!state)
 175                 do_update = true;
 176         else
 177                 do_update = false;
 178
 179         next_report = ktime_add(button->last_time,
 180                                 ms_to_ktime(lid_report_interval));
 181         if (button->last_state == !!state &&
 182             ktime_after(ktime_get(), next_report)) {
 183                 /* Complain the buggy firmware */
 184                 pr_warn_once("The lid device is not compliant to SW_LID.\n");
 185
 186                 /*
 187                  * Send the unreliable complement switch event:
 188                  *
 189                  * On most platforms, the lid device is reliable. However
 190                  * there are exceptions:
 191                  * 1. Platforms returning initial lid state as "close" by
 192                  *    default after booting/resuming:
 193                  *     https://bugzilla.kernel.org/show_bug.cgi?id=89211
 194                  *     https://bugzilla.kernel.org/show_bug.cgi?id=106151
 195                  * 2. Platforms never reporting "open" events:
 196                  *     https://bugzilla.kernel.org/show_bug.cgi?id=106941
 197                  * On these buggy platforms, the usage model of the ACPI
 198                  * lid device actually is:
 199                  * 1. The initial returning value of _LID may not be
 200                  *    reliable.
 201                  * 2. The open event may not be reliable.
 202                  * 3. The close event is reliable.
 203                  *
 204                  * But SW_LID is typed as input switch event, the input
 205                  * layer checks if the event is redundant. Hence if the
 206                  * state is not switched, the userspace cannot see this
 207                  * platform triggered reliable event. By inserting a
 208                  * complement switch event, it then is guaranteed that the
 209                  * platform triggered reliable one can always be seen by
 210                  * the userspace.
 211                  */
 212                 if (lid_init_state == ACPI_BUTTON_LID_INIT_IGNORE) {
 213                         do_update = true;
 214                         /*
 215                          * Do generate complement switch event for "close"
 216                          * as "close" is reliable and wrong "open" won't
 217                          * trigger unexpected behaviors.
 218                          * Do not generate complement switch event for
 219                          * "open" as "open" is not reliable and wrong
 220                          * "close" will trigger unexpected behaviors.
 221                          */
 222                         if (!state) {
 223                                 input_report_switch(button->input,
 224                                                     SW_LID, state);
 225                                 input_sync(button->input);
 226                         }
 227                 }
 228         }
 229         /* Send the platform triggered reliable event */
 230         if (do_update) {
 231                 acpi_handle_debug(device->handle, "ACPI LID %s\n",
 232                                   state ? "open" : "closed");
 233                 input_report_switch(button->input, SW_LID, !state);
 234                 input_sync(button->input);
 235                 button->last_state = !!state;
 236                 button->last_time = ktime_get();
 237         }
 238
 239         ret = blocking_notifier_call_chain(&acpi_lid_notifier, state, device);
 240         if (ret == NOTIFY_DONE)
 241                 ret = blocking_notifier_call_chain(&acpi_lid_notifier, state,
 242                                                    device);
 243         if (ret == NOTIFY_DONE || ret == NOTIFY_OK) {
 244                 /*
 245                  * It is also regarded as success if the notifier_chain
 246                  * returns NOTIFY_OK or NOTIFY_DONE.
 247                  */
 248                 ret = 0;
 249         }
 250         return ret;
 251 }
 252
 253 static int __maybe_unused acpi_button_state_seq_show(struct seq_file *seq,
 254                                                      void *offset)
 255 {
 256         struct acpi_device *device = seq->private;
 257         int state;
 258
 259         state = acpi_lid_evaluate_state(device);
 260         seq_printf(seq, "state:      %s\n",
 261                    state < 0 ? "unsupported" : (state ? "open" : "closed"));
 262         return 0;
 263 }
 264
 265 static int acpi_button_add_fs(struct acpi_device *device)
 266 {
 267         struct acpi_button *button = acpi_driver_data(device);
 268         struct proc_dir_entry *entry = NULL;
 269         int ret = 0;
 270
 271         /* procfs I/F for ACPI lid device only */
 272         if (button->type != ACPI_BUTTON_TYPE_LID)
 273                 return 0;
 274
 275         if (acpi_button_dir || acpi_lid_dir) {
 276                 printk(KERN_ERR PREFIX "More than one Lid device found!\n");
 277                 return -EEXIST;
 278         }
 279
 280         /* create /proc/acpi/button */
 281         acpi_button_dir = proc_mkdir(ACPI_BUTTON_CLASS, acpi_root_dir);
 282         if (!acpi_button_dir)
 283                 return -ENODEV;
 284
 285         /* create /proc/acpi/button/lid */
 286         acpi_lid_dir = proc_mkdir(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 287         if (!acpi_lid_dir) {
 288                 ret = -ENODEV;
 289                 goto remove_button_dir;
 290         }
 291
 292         /* create /proc/acpi/button/lid/LID/ */
 293         acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device), acpi_lid_dir);
 294         if (!acpi_device_dir(device)) {
 295                 ret = -ENODEV;
 296                 goto remove_lid_dir;
 297         }
 298
 299         /* create /proc/acpi/button/lid/LID/state */
 300         entry = proc_create_single_data(ACPI_BUTTON_FILE_STATE, S_IRUGO,
 301                         acpi_device_dir(device), acpi_button_state_seq_show,
 302                         device);
 303         if (!entry) {
 304                 ret = -ENODEV;
 305                 goto remove_dev_dir;
 306         }
 307
 308 done:
 309         return ret;
 310
 311 remove_dev_dir:
 312         remove_proc_entry(acpi_device_bid(device),
 313                           acpi_lid_dir);
 314         acpi_device_dir(device) = NULL;
 315 remove_lid_dir:
 316         remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 317         acpi_lid_dir = NULL;
 318 remove_button_dir:
 319         remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
 320         acpi_button_dir = NULL;
 321         goto done;
 322 }
 323
 324 static int acpi_button_remove_fs(struct acpi_device *device)
 325 {
 326         struct acpi_button *button = acpi_driver_data(device);
 327
 328         if (button->type != ACPI_BUTTON_TYPE_LID)
 329                 return 0;
 330
 331         remove_proc_entry(ACPI_BUTTON_FILE_STATE,
 332                           acpi_device_dir(device));
 333         remove_proc_entry(acpi_device_bid(device),
 334                           acpi_lid_dir);
 335         acpi_device_dir(device) = NULL;
 336         remove_proc_entry(ACPI_BUTTON_SUBCLASS_LID, acpi_button_dir);
 337         acpi_lid_dir = NULL;
 338         remove_proc_entry(ACPI_BUTTON_CLASS, acpi_root_dir);
 339         acpi_button_dir = NULL;
 340
 341         return 0;
 342 }
 343
 344 /* --------------------------------------------------------------------------
 345                                 Driver Interface
 346    -------------------------------------------------------------------------- */
 347 int acpi_lid_notifier_register(struct notifier_block *nb)
 348 {
 349         return blocking_notifier_chain_register(&acpi_lid_notifier, nb);
 350 }
 351 EXPORT_SYMBOL(acpi_lid_notifier_register);
 352
 353 int acpi_lid_notifier_unregister(struct notifier_block *nb)
 354 {
 355         return blocking_notifier_chain_unregister(&acpi_lid_notifier, nb);
 356 }
 357 EXPORT_SYMBOL(acpi_lid_notifier_unregister);
 358
 359 int acpi_lid_open(void)
 360 {
 361         if (!lid_device)
 362                 return -ENODEV;
 363
 364         return acpi_lid_evaluate_state(lid_device);
 365 }
 366 EXPORT_SYMBOL(acpi_lid_open);
 367
 368 static int acpi_lid_update_state(struct acpi_device *device,
 369                                  bool signal_wakeup)
 370 {
 371         int state;
 372
 373         state = acpi_lid_evaluate_state(device);
 374         if (state < 0)
 375                 return state;
 376
 377         if (state && signal_wakeup)
 378                 acpi_pm_wakeup_event(&device->dev);
 379
 380         return acpi_lid_notify_state(device, state);
 381 }
 382
 383 static void acpi_lid_initialize_state(struct acpi_device *device)
 384 {
 385         switch (lid_init_state) {
 386         case ACPI_BUTTON_LID_INIT_OPEN:
 387                 (void)acpi_lid_notify_state(device, 1);
 388                 break;
 389         case ACPI_BUTTON_LID_INIT_METHOD:
 390                 (void)acpi_lid_update_state(device, false);
 391                 break;
 392         case ACPI_BUTTON_LID_INIT_IGNORE:
 393         default:
 394                 break;
 395         }
 396 }
 397
 398 static void acpi_button_notify(struct acpi_device *device, u32 event)
 399 {
 400         struct acpi_button *button = acpi_driver_data(device);
 401         struct input_dev *input;
 402         int users;
 403
 404         switch (event) {
 405         case ACPI_FIXED_HARDWARE_EVENT:
 406                 event = ACPI_BUTTON_NOTIFY_STATUS;
 407                 /* fall through */
 408         case ACPI_BUTTON_NOTIFY_STATUS:
 409                 input = button->input;
 410                 if (button->type == ACPI_BUTTON_TYPE_LID) {
 411                         mutex_lock(&button->input->mutex);
 412                         users = button->input->users;
 413                         mutex_unlock(&button->input->mutex);
 414                         if (users)
 415                                 acpi_lid_update_state(device, true);
 416                 } else {
 417                         int keycode;
 418
 419                         acpi_pm_wakeup_event(&device->dev);
 420                         if (button->suspended)
 421                                 break;
 422
 423                         keycode = test_bit(KEY_SLEEP, input->keybit) ?
 424                                                 KEY_SLEEP : KEY_POWER;
 425                         input_report_key(input, keycode, 1);
 426                         input_sync(input);
 427                         input_report_key(input, keycode, 0);
 428                         input_sync(input);
 429
 430                         acpi_bus_generate_netlink_event(
 431                                         device->pnp.device_class,
 432                                         dev_name(&device->dev),
 433                                         event, ++button->pushed);
 434                 }
 435                 break;
 436         default:
 437                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 438                                   "Unsupported event [0x%x]\n", event));
 439                 break;
 440         }
 441 }
 442
 443 #ifdef CONFIG_PM_SLEEP
 444 static int acpi_button_suspend(struct device *dev)
 445 {
 446         struct acpi_device *device = to_acpi_device(dev);
 447         struct acpi_button *button = acpi_driver_data(device);
 448
 449         button->suspended = true;
 450         return 0;
 451 }
 452
 453 static int acpi_button_resume(struct device *dev)
 454 {
 455         struct acpi_device *device = to_acpi_device(dev);
 456         struct acpi_button *button = acpi_driver_data(device);
 457
 458         button->suspended = false;
 459         if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users)
 460                 acpi_lid_initialize_state(device);
 461         return 0;
 462 }
 463 #endif
 464
 465 static int acpi_lid_input_open(struct input_dev *input)
 466 {
 467         struct acpi_device *device = input_get_drvdata(input);
 468         struct acpi_button *button = acpi_driver_data(device);
 469
 470         button->last_state = !!acpi_lid_evaluate_state(device);
 471         button->last_time = ktime_get();
 472         acpi_lid_initialize_state(device);
 473
 474         return 0;
 475 }
 476
 477 static int acpi_button_add(struct acpi_device *device)
 478 {
 479         struct acpi_button *button;
 480         struct input_dev *input;
 481         const char *hid = acpi_device_hid(device);
 482         char *name, *class;
 483         int error;
 484
 485         if (!strcmp(hid, ACPI_BUTTON_HID_LID) && dmi_check_system(lid_blacklst))
 486                 return -ENODEV;
 487
 488         button = kzalloc(sizeof(struct acpi_button), GFP_KERNEL);
 489         if (!button)
 490                 return -ENOMEM;
 491
 492         device->driver_data = button;
 493
 494         button->input = input = input_allocate_device();
 495         if (!input) {
 496                 error = -ENOMEM;
 497                 goto err_free_button;
 498         }
 499
 500         name = acpi_device_name(device);
 501         class = acpi_device_class(device);
 502
 503         if (!strcmp(hid, ACPI_BUTTON_HID_POWER) ||
 504             !strcmp(hid, ACPI_BUTTON_HID_POWERF)) {
 505                 button->type = ACPI_BUTTON_TYPE_POWER;
 506                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_POWER);
 507                 sprintf(class, "%s/%s",
 508                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_POWER);
 509         } else if (!strcmp(hid, ACPI_BUTTON_HID_SLEEP) ||
 510                    !strcmp(hid, ACPI_BUTTON_HID_SLEEPF)) {
 511                 button->type = ACPI_BUTTON_TYPE_SLEEP;
 512                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_SLEEP);
 513                 sprintf(class, "%s/%s",
 514                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_SLEEP);
 515         } else if (!strcmp(hid, ACPI_BUTTON_HID_LID)) {
 516                 button->type = ACPI_BUTTON_TYPE_LID;
 517                 strcpy(name, ACPI_BUTTON_DEVICE_NAME_LID);
 518                 sprintf(class, "%s/%s",
 519                         ACPI_BUTTON_CLASS, ACPI_BUTTON_SUBCLASS_LID);
 520                 input->open = acpi_lid_input_open;
 521         } else {
 522                 printk(KERN_ERR PREFIX "Unsupported hid [%s]\n", hid);
 523                 error = -ENODEV;
 524                 goto err_free_input;
 525         }
 526
 527         error = acpi_button_add_fs(device);
 528         if (error)
 529                 goto err_free_input;
 530
 531         snprintf(button->phys, sizeof(button->phys), "%s/button/input0", hid);
 532
 533         input->name = name;
 534         input->phys = button->phys;
 535         input->id.bustype = BUS_HOST;
 536         input->id.product = button->type;
 537         input->dev.parent = &device->dev;
 538
 539         switch (button->type) {
 540         case ACPI_BUTTON_TYPE_POWER:
 541                 input_set_capability(input, EV_KEY, KEY_POWER);
 542                 break;
 543
 544         case ACPI_BUTTON_TYPE_SLEEP:
 545                 input_set_capability(input, EV_KEY, KEY_SLEEP);
 546                 break;
 547
 548         case ACPI_BUTTON_TYPE_LID:
 549                 input_set_capability(input, EV_SW, SW_LID);
 550                 break;
 551         }
 552
 553         input_set_drvdata(input, device);
 554         error = input_register_device(input);
 555         if (error)
 556                 goto err_remove_fs;
 557         if (button->type == ACPI_BUTTON_TYPE_LID) {
 558                 /*
 559                  * This assumes there's only one lid device, or if there are
 560                  * more we only care about the last one...
 561                  */
 562                 lid_device = device;
 563         }
 564
 565         device_init_wakeup(&device->dev, true);
 566         printk(KERN_INFO PREFIX "%s [%s]\n", name, acpi_device_bid(device));
 567         return 0;
 568
 569  err_remove_fs:
 570         acpi_button_remove_fs(device);
 571  err_free_input:
 572         input_free_device(input);
 573  err_free_button:
 574         kfree(button);
 575         return error;
 576 }
 577
 578 static int acpi_button_remove(struct acpi_device *device)
 579 {
 580         struct acpi_button *button = acpi_driver_data(device);
 581
 582         acpi_button_remove_fs(device);
 583         input_unregister_device(button->input);
 584         kfree(button);
 585         return 0;
 586 }
 587
 588 static int param_set_lid_init_state(const char *val,
 589                                     const struct kernel_param *kp)
 590 {
 591         int result = 0;
 592
 593         if (!strncmp(val, "open", sizeof("open") - 1)) {
 594                 lid_init_state = ACPI_BUTTON_LID_INIT_OPEN;
 595                 pr_info("Notify initial lid state as open\n");
 596         } else if (!strncmp(val, "method", sizeof("method") - 1)) {
 597                 lid_init_state = ACPI_BUTTON_LID_INIT_METHOD;
 598                 pr_info("Notify initial lid state with _LID return value\n");
 599         } else if (!strncmp(val, "ignore", sizeof("ignore") - 1)) {
 600                 lid_init_state = ACPI_BUTTON_LID_INIT_IGNORE;
 601                 pr_info("Do not notify initial lid state\n");
 602         } else
 603                 result = -EINVAL;
 604         return result;
 605 }
 606
 607 static int param_get_lid_init_state(char *buffer,
 608                                     const struct kernel_param *kp)
 609 {
 610         switch (lid_init_state) {
 611         case ACPI_BUTTON_LID_INIT_OPEN:
 612                 return sprintf(buffer, "open");
 613         case ACPI_BUTTON_LID_INIT_METHOD:
 614                 return sprintf(buffer, "method");
 615         case ACPI_BUTTON_LID_INIT_IGNORE:
 616                 return sprintf(buffer, "ignore");
 617         default:
 618                 return sprintf(buffer, "invalid");
 619         }
 620         return 0;
 621 }
 622
 623 module_param_call(lid_init_state,
 624                   param_set_lid_init_state, param_get_lid_init_state,
 625                   NULL, 0644);
 626 MODULE_PARM_DESC(lid_init_state, "Behavior for reporting LID initial state");
 627
 628 static int acpi_button_register_driver(struct acpi_driver *driver)
 629 {
 630         /*
 631          * Modules such as nouveau.ko and i915.ko have a link time dependency
 632          * on acpi_lid_open(), and would therefore not be loadable on ACPI
 633          * capable kernels booted in non-ACPI mode if the return value of
 634          * acpi_bus_register_driver() is returned from here with ACPI disabled
 635          * when this driver is built as a module.
 636          */
 637         if (acpi_disabled)
 638                 return 0;
 639
 640         return acpi_bus_register_driver(driver);
 641 }
 642
 643 static void acpi_button_unregister_driver(struct acpi_driver *driver)
 644 {
 645         if (!acpi_disabled)
 646                 acpi_bus_unregister_driver(driver);
 647 }
 648
 649 module_driver(acpi_button_driver, acpi_button_register_driver,
 650                acpi_button_unregister_driver);