drivers/extcon/extcon.c

   1 /*
   2  *  drivers/extcon/extcon_class.c
   3  *
   4  *  External connector (extcon) class driver
   5  *
   6  * Copyright (C) 2012 Samsung Electronics
   7  * Author: Donggeun Kim <dg77.kim@samsung.com>
   8  * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
   9  *
  10  * based on android/drivers/switch/switch_class.c
  11  * Copyright (C) 2008 Google, Inc.
  12  * Author: Mike Lockwood <lockwood@android.com>
  13  *
  14  * This software is licensed under the terms of the GNU General Public
  15  * License version 2, as published by the Free Software Foundation, and
  16  * may be copied, distributed, and modified under those terms.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23 */
  24
  25 #include <linux/module.h>
  26 #include <linux/types.h>
  27 #include <linux/init.h>
  28 #include <linux/device.h>
  29 #include <linux/fs.h>
  30 #include <linux/err.h>
  31 #include <linux/extcon.h>
  32 #include <linux/of.h>
  33 #include <linux/slab.h>
  34 #include <linux/sysfs.h>
  35
  36 /*
  37  * extcon_cable_name suggests the standard cable names for commonly used
  38  * cable types.
  39  *
  40  * However, please do not use extcon_cable_name directly for extcon_dev
  41  * struct's supported_cable pointer unless your device really supports
  42  * every single port-type of the following cable names. Please choose cable
  43  * names that are actually used in your extcon device.
  44  */
  45 const char extcon_cable_name[][CABLE_NAME_MAX + 1] = {
  46         [EXTCON_USB]            = "USB",
  47         [EXTCON_USB_HOST]       = "USB-Host",
  48         [EXTCON_TA]             = "TA",
  49         [EXTCON_FAST_CHARGER]   = "Fast-charger",
  50         [EXTCON_SLOW_CHARGER]   = "Slow-charger",
  51         [EXTCON_CHARGE_DOWNSTREAM]      = "Charge-downstream",
  52         [EXTCON_HDMI]           = "HDMI",
  53         [EXTCON_MHL]            = "MHL",
  54         [EXTCON_DVI]            = "DVI",
  55         [EXTCON_VGA]            = "VGA",
  56         [EXTCON_DOCK]           = "Dock",
  57         [EXTCON_LINE_IN]        = "Line-in",
  58         [EXTCON_LINE_OUT]       = "Line-out",
  59         [EXTCON_MIC_IN]         = "Microphone",
  60         [EXTCON_HEADPHONE_OUT]  = "Headphone",
  61         [EXTCON_SPDIF_IN]       = "SPDIF-in",
  62         [EXTCON_SPDIF_OUT]      = "SPDIF-out",
  63         [EXTCON_VIDEO_IN]       = "Video-in",
  64         [EXTCON_VIDEO_OUT]      = "Video-out",
  65         [EXTCON_MECHANICAL]     = "Mechanical",
  66 };
  67
  68 static struct class *extcon_class;
  69 #if defined(CONFIG_ANDROID)
  70 static struct class_compat *switch_class;
  71 #endif /* CONFIG_ANDROID */
  72
  73 static LIST_HEAD(extcon_dev_list);
  74 static DEFINE_MUTEX(extcon_dev_list_lock);
  75
  76 /**
  77  * check_mutually_exclusive - Check if new_state violates mutually_exclusive
  78  *                            condition.
  79  * @edev:       the extcon device
  80  * @new_state:  new cable attach status for @edev
  81  *
  82  * Returns 0 if nothing violates. Returns the index + 1 for the first
  83  * violated condition.
  84  */
  85 static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
  86 {
  87         int i = 0;
  88
  89         if (!edev->mutually_exclusive)
  90                 return 0;
  91
  92         for (i = 0; edev->mutually_exclusive[i]; i++) {
  93                 int weight;
  94                 u32 correspondants = new_state & edev->mutually_exclusive[i];
  95
  96                 /* calculate the total number of bits set */
  97                 weight = hweight32(correspondants);
  98                 if (weight > 1)
  99                         return i + 1;
 100         }
 101
 102         return 0;
 103 }
 104
 105 static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 106                           char *buf)
 107 {
 108         int i, count = 0;
 109         struct extcon_dev *edev = dev_get_drvdata(dev);
 110
 111         if (edev->print_state) {
 112                 int ret = edev->print_state(edev, buf);
 113
 114                 if (ret >= 0)
 115                         return ret;
 116                 /* Use default if failed */
 117         }
 118
 119         if (edev->max_supported == 0)
 120                 return sprintf(buf, "%u\n", edev->state);
 121
 122         for (i = 0; i < SUPPORTED_CABLE_MAX; i++) {
 123                 if (!edev->supported_cable[i])
 124                         break;
 125                 count += sprintf(buf + count, "%s=%d\n",
 126                                  edev->supported_cable[i],
 127                                  !!(edev->state & (1 << i)));
 128         }
 129
 130         return count;
 131 }
 132
 133 static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 134                            const char *buf, size_t count)
 135 {
 136         u32 state;
 137         ssize_t ret = 0;
 138         struct extcon_dev *edev = dev_get_drvdata(dev);
 139
 140         ret = sscanf(buf, "0x%x", &state);
 141         if (ret == 0)
 142                 ret = -EINVAL;
 143         else
 144                 ret = extcon_set_state(edev, state);
 145
 146         if (ret < 0)
 147                 return ret;
 148
 149         return count;
 150 }
 151 static DEVICE_ATTR_RW(state);
 152
 153 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 154                 char *buf)
 155 {
 156         struct extcon_dev *edev = dev_get_drvdata(dev);
 157
 158         /* Optional callback given by the user */
 159         if (edev->print_name) {
 160                 int ret = edev->print_name(edev, buf);
 161
 162                 if (ret >= 0)
 163                         return ret;
 164         }
 165
 166         return sprintf(buf, "%s\n", edev->name);
 167 }
 168 static DEVICE_ATTR_RO(name);
 169
 170 static ssize_t cable_name_show(struct device *dev,
 171                                struct device_attribute *attr, char *buf)
 172 {
 173         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 174                                                   attr_name);
 175
 176         return sprintf(buf, "%s\n",
 177                        cable->edev->supported_cable[cable->cable_index]);
 178 }
 179
 180 static ssize_t cable_state_show(struct device *dev,
 181                                 struct device_attribute *attr, char *buf)
 182 {
 183         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 184                                                   attr_state);
 185
 186         return sprintf(buf, "%d\n",
 187                        extcon_get_cable_state_(cable->edev,
 188                                                cable->cable_index));
 189 }
 190
 191 /**
 192  * extcon_update_state() - Update the cable attach states of the extcon device
 193  *                         only for the masked bits.
 194  * @edev:       the extcon device
 195  * @mask:       the bit mask to designate updated bits.
 196  * @state:      new cable attach status for @edev
 197  *
 198  * Changing the state sends uevent with environment variable containing
 199  * the name of extcon device (envp[0]) and the state output (envp[1]).
 200  * Tizen uses this format for extcon device to get events from ports.
 201  * Android uses this format as well.
 202  *
 203  * Note that the notifier provides which bits are changed in the state
 204  * variable with the val parameter (second) to the callback.
 205  */
 206 int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
 207 {
 208         char name_buf[120];
 209         char state_buf[120];
 210         char *prop_buf;
 211         char *envp[3];
 212         int env_offset = 0;
 213         int length;
 214         unsigned long flags;
 215
 216         spin_lock_irqsave(&edev->lock, flags);
 217
 218         if (edev->state != ((edev->state & ~mask) | (state & mask))) {
 219                 u32 old_state = edev->state;
 220
 221                 if (check_mutually_exclusive(edev, (edev->state & ~mask) |
 222                                                    (state & mask))) {
 223                         spin_unlock_irqrestore(&edev->lock, flags);
 224                         return -EPERM;
 225                 }
 226
 227                 edev->state &= ~mask;
 228                 edev->state |= state & mask;
 229
 230                 raw_notifier_call_chain(&edev->nh, old_state, edev);
 231                 /* This could be in interrupt handler */
 232                 prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
 233                 if (prop_buf) {
 234                         length = name_show(&edev->dev, NULL, prop_buf);
 235                         if (length > 0) {
 236                                 if (prop_buf[length - 1] == '\n')
 237                                         prop_buf[length - 1] = 0;
 238                                 snprintf(name_buf, sizeof(name_buf),
 239                                         "NAME=%s", prop_buf);
 240                                 envp[env_offset++] = name_buf;
 241                         }
 242                         length = state_show(&edev->dev, NULL, prop_buf);
 243                         if (length > 0) {
 244                                 if (prop_buf[length - 1] == '\n')
 245                                         prop_buf[length - 1] = 0;
 246                                 snprintf(state_buf, sizeof(state_buf),
 247                                         "STATE=%s", prop_buf);
 248                                 envp[env_offset++] = state_buf;
 249                         }
 250                         envp[env_offset] = NULL;
 251                         /* Unlock early before uevent */
 252                         spin_unlock_irqrestore(&edev->lock, flags);
 253
 254                         kobject_uevent_env(&edev->dev.kobj, KOBJ_CHANGE, envp);
 255                         free_page((unsigned long)prop_buf);
 256                 } else {
 257                         /* Unlock early before uevent */
 258                         spin_unlock_irqrestore(&edev->lock, flags);
 259
 260                         dev_err(&edev->dev, "out of memory in extcon_set_state\n");
 261                         kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
 262                 }
 263         } else {
 264                 /* No changes */
 265                 spin_unlock_irqrestore(&edev->lock, flags);
 266         }
 267
 268         return 0;
 269 }
 270 EXPORT_SYMBOL_GPL(extcon_update_state);
 271
 272 /**
 273  * extcon_set_state() - Set the cable attach states of the extcon device.
 274  * @edev:       the extcon device
 275  * @state:      new cable attach status for @edev
 276  *
 277  * Note that notifier provides which bits are changed in the state
 278  * variable with the val parameter (second) to the callback.
 279  */
 280 int extcon_set_state(struct extcon_dev *edev, u32 state)
 281 {
 282         return extcon_update_state(edev, 0xffffffff, state);
 283 }
 284 EXPORT_SYMBOL_GPL(extcon_set_state);
 285
 286 /**
 287  * extcon_find_cable_index() - Get the cable index based on the cable name.
 288  * @edev:       the extcon device that has the cable.
 289  * @cable_name: cable name to be searched.
 290  *
 291  * Note that accessing a cable state based on cable_index is faster than
 292  * cable_name because using cable_name induces a loop with strncmp().
 293  * Thus, when get/set_cable_state is repeatedly used, using cable_index
 294  * is recommended.
 295  */
 296 int extcon_find_cable_index(struct extcon_dev *edev, const char *cable_name)
 297 {
 298         int i;
 299
 300         if (edev->supported_cable) {
 301                 for (i = 0; edev->supported_cable[i]; i++) {
 302                         if (!strncmp(edev->supported_cable[i],
 303                                 cable_name, CABLE_NAME_MAX))
 304                                 return i;
 305                 }
 306         }
 307
 308         return -EINVAL;
 309 }
 310 EXPORT_SYMBOL_GPL(extcon_find_cable_index);
 311
 312 /**
 313  * extcon_get_cable_state_() - Get the status of a specific cable.
 314  * @edev:       the extcon device that has the cable.
 315  * @index:      cable index that can be retrieved by extcon_find_cable_index().
 316  */
 317 int extcon_get_cable_state_(struct extcon_dev *edev, int index)
 318 {
 319         if (index < 0 || (edev->max_supported && edev->max_supported <= index))
 320                 return -EINVAL;
 321
 322         return !!(edev->state & (1 << index));
 323 }
 324 EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
 325
 326 /**
 327  * extcon_get_cable_state() - Get the status of a specific cable.
 328  * @edev:       the extcon device that has the cable.
 329  * @cable_name: cable name.
 330  *
 331  * Note that this is slower than extcon_get_cable_state_.
 332  */
 333 int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
 334 {
 335         return extcon_get_cable_state_(edev, extcon_find_cable_index
 336                                                 (edev, cable_name));
 337 }
 338 EXPORT_SYMBOL_GPL(extcon_get_cable_state);
 339
 340 /**
 341  * extcon_set_cable_state_() - Set the status of a specific cable.
 342  * @edev:               the extcon device that has the cable.
 343  * @index:              cable index that can be retrieved by
 344  *                      extcon_find_cable_index().
 345  * @cable_state:        the new cable status. The default semantics is
 346  *                      true: attached / false: detached.
 347  */
 348 int extcon_set_cable_state_(struct extcon_dev *edev,
 349                         int index, bool cable_state)
 350 {
 351         u32 state;
 352
 353         if (index < 0 || (edev->max_supported && edev->max_supported <= index))
 354                 return -EINVAL;
 355
 356         state = cable_state ? (1 << index) : 0;
 357         return extcon_update_state(edev, 1 << index, state);
 358 }
 359 EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
 360
 361 /**
 362  * extcon_set_cable_state() - Set the status of a specific cable.
 363  * @edev:               the extcon device that has the cable.
 364  * @cable_name:         cable name.
 365  * @cable_state:        the new cable status. The default semantics is
 366  *                      true: attached / false: detached.
 367  *
 368  * Note that this is slower than extcon_set_cable_state_.
 369  */
 370 int extcon_set_cable_state(struct extcon_dev *edev,
 371                         const char *cable_name, bool cable_state)
 372 {
 373         return extcon_set_cable_state_(edev, extcon_find_cable_index
 374                                         (edev, cable_name), cable_state);
 375 }
 376 EXPORT_SYMBOL_GPL(extcon_set_cable_state);
 377
 378 /**
 379  * extcon_get_extcon_dev() - Get the extcon device instance from the name
 380  * @extcon_name:        The extcon name provided with extcon_dev_register()
 381  */
 382 struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 383 {
 384         struct extcon_dev *sd;
 385
 386         mutex_lock(&extcon_dev_list_lock);
 387         list_for_each_entry(sd, &extcon_dev_list, entry) {
 388                 if (!strcmp(sd->name, extcon_name))
 389                         goto out;
 390         }
 391         sd = NULL;
 392 out:
 393         mutex_unlock(&extcon_dev_list_lock);
 394         return sd;
 395 }
 396 EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);
 397
 398 static int _call_per_cable(struct notifier_block *nb, unsigned long val,
 399                            void *ptr)
 400 {
 401         struct extcon_specific_cable_nb *obj = container_of(nb,
 402                         struct extcon_specific_cable_nb, internal_nb);
 403         struct extcon_dev *edev = ptr;
 404
 405         if ((val & (1 << obj->cable_index)) !=
 406             (edev->state & (1 << obj->cable_index))) {
 407                 bool cable_state = true;
 408
 409                 obj->previous_value = val;
 410
 411                 if (val & (1 << obj->cable_index))
 412                         cable_state = false;
 413
 414                 return obj->user_nb->notifier_call(obj->user_nb,
 415                                 cable_state, ptr);
 416         }
 417
 418         return NOTIFY_OK;
 419 }
 420
 421 /**
 422  * extcon_register_interest() - Register a notifier for a state change of a
 423  *                              specific cable, not an entier set of cables of a
 424  *                              extcon device.
 425  * @obj:                an empty extcon_specific_cable_nb object to be returned.
 426  * @extcon_name:        the name of extcon device.
 427  *                      if NULL, extcon_register_interest will register
 428  *                      every cable with the target cable_name given.
 429  * @cable_name:         the target cable name.
 430  * @nb:                 the notifier block to get notified.
 431  *
 432  * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets
 433  * the struct for you.
 434  *
 435  * extcon_register_interest is a helper function for those who want to get
 436  * notification for a single specific cable's status change. If a user wants
 437  * to get notification for any changes of all cables of a extcon device,
 438  * he/she should use the general extcon_register_notifier().
 439  *
 440  * Note that the second parameter given to the callback of nb (val) is
 441  * "old_state", not the current state. The current state can be retrieved
 442  * by looking at the third pameter (edev pointer)'s state value.
 443  */
 444 int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 445                              const char *extcon_name, const char *cable_name,
 446                              struct notifier_block *nb)
 447 {
 448         unsigned long flags;
 449         int ret;
 450
 451         if (!obj || !cable_name || !nb)
 452                 return -EINVAL;
 453
 454         if (extcon_name) {
 455                 obj->edev = extcon_get_extcon_dev(extcon_name);
 456                 if (!obj->edev)
 457                         return -ENODEV;
 458
 459                 obj->cable_index = extcon_find_cable_index(obj->edev,
 460                                                           cable_name);
 461                 if (obj->cable_index < 0)
 462                         return obj->cable_index;
 463
 464                 obj->user_nb = nb;
 465
 466                 obj->internal_nb.notifier_call = _call_per_cable;
 467
 468                 spin_lock_irqsave(&obj->edev->lock, flags);
 469                 ret = raw_notifier_chain_register(&obj->edev->nh,
 470                                                   &obj->internal_nb);
 471                 spin_unlock_irqrestore(&obj->edev->lock, flags);
 472                 return ret;
 473         } else {
 474                 struct class_dev_iter iter;
 475                 struct extcon_dev *extd;
 476                 struct device *dev;
 477
 478                 if (!extcon_class)
 479                         return -ENODEV;
 480                 class_dev_iter_init(&iter, extcon_class, NULL, NULL);
 481                 while ((dev = class_dev_iter_next(&iter))) {
 482                         extd = dev_get_drvdata(dev);
 483
 484                         if (extcon_find_cable_index(extd, cable_name) < 0)
 485                                 continue;
 486
 487                         class_dev_iter_exit(&iter);
 488                         return extcon_register_interest(obj, extd->name,
 489                                                 cable_name, nb);
 490                 }
 491
 492                 return -ENODEV;
 493         }
 494 }
 495 EXPORT_SYMBOL_GPL(extcon_register_interest);
 496
 497 /**
 498  * extcon_unregister_interest() - Unregister the notifier registered by
 499  *                                extcon_register_interest().
 500  * @obj:        the extcon_specific_cable_nb object returned by
 501  *              extcon_register_interest().
 502  */
 503 int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
 504 {
 505         unsigned long flags;
 506         int ret;
 507
 508         if (!obj)
 509                 return -EINVAL;
 510
 511         spin_lock_irqsave(&obj->edev->lock, flags);
 512         ret = raw_notifier_chain_unregister(&obj->edev->nh, &obj->internal_nb);
 513         spin_unlock_irqrestore(&obj->edev->lock, flags);
 514
 515         return ret;
 516 }
 517 EXPORT_SYMBOL_GPL(extcon_unregister_interest);
 518
 519 /**
 520  * extcon_register_notifier() - Register a notifiee to get notified by
 521  *                              any attach status changes from the extcon.
 522  * @edev:       the extcon device.
 523  * @nb:         a notifier block to be registered.
 524  *
 525  * Note that the second parameter given to the callback of nb (val) is
 526  * "old_state", not the current state. The current state can be retrieved
 527  * by looking at the third pameter (edev pointer)'s state value.
 528  */
 529 int extcon_register_notifier(struct extcon_dev *edev,
 530                         struct notifier_block *nb)
 531 {
 532         unsigned long flags;
 533         int ret;
 534
 535         spin_lock_irqsave(&edev->lock, flags);
 536         ret = raw_notifier_chain_register(&edev->nh, nb);
 537         spin_unlock_irqrestore(&edev->lock, flags);
 538
 539         return ret;
 540 }
 541 EXPORT_SYMBOL_GPL(extcon_register_notifier);
 542
 543 /**
 544  * extcon_unregister_notifier() - Unregister a notifiee from the extcon device.
 545  * @edev:       the extcon device.
 546  * @nb:         a registered notifier block to be unregistered.
 547  */
 548 int extcon_unregister_notifier(struct extcon_dev *edev,
 549                         struct notifier_block *nb)
 550 {
 551         unsigned long flags;
 552         int ret;
 553
 554         spin_lock_irqsave(&edev->lock, flags);
 555         ret = raw_notifier_chain_unregister(&edev->nh, nb);
 556         spin_unlock_irqrestore(&edev->lock, flags);
 557
 558         return ret;
 559 }
 560 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
 561
 562 static struct attribute *extcon_attrs[] = {
 563         &dev_attr_state.attr,
 564         &dev_attr_name.attr,
 565         NULL,
 566 };
 567 ATTRIBUTE_GROUPS(extcon);
 568
 569 static int create_extcon_class(void)
 570 {
 571         if (!extcon_class) {
 572                 extcon_class = class_create(THIS_MODULE, "extcon");
 573                 if (IS_ERR(extcon_class))
 574                         return PTR_ERR(extcon_class);
 575                 extcon_class->dev_groups = extcon_groups;
 576
 577 #if defined(CONFIG_ANDROID)
 578                 switch_class = class_compat_register("switch");
 579                 if (WARN(!switch_class, "cannot allocate"))
 580                         return -ENOMEM;
 581 #endif /* CONFIG_ANDROID */
 582         }
 583
 584         return 0;
 585 }
 586
 587 static void extcon_dev_release(struct device *dev)
 588 {
 589 }
 590
 591 static const char *muex_name = "mutually_exclusive";
 592 static void dummy_sysfs_dev_release(struct device *dev)
 593 {
 594 }
 595
 596 /*
 597  * extcon_dev_allocate() - Allocate the memory of extcon device.
 598  * @supported_cable:    Array of supported cable names ending with NULL.
 599  *                      If supported_cable is NULL, cable name related APIs
 600  *                      are disabled.
 601  *
 602  * This function allocates the memory for extcon device without allocating
 603  * memory in each extcon provider driver and initialize default setting for
 604  * extcon device.
 605  *
 606  * Return the pointer of extcon device if success or ERR_PTR(err) if fail
 607  */
 608 struct extcon_dev *extcon_dev_allocate(const char **supported_cable)
 609 {
 610         struct extcon_dev *edev;
 611
 612         edev = kzalloc(sizeof(*edev), GFP_KERNEL);
 613         if (!edev)
 614                 return ERR_PTR(-ENOMEM);
 615
 616         edev->max_supported = 0;
 617         edev->supported_cable = supported_cable;
 618
 619         return edev;
 620 }
 621
 622 /*
 623  * extcon_dev_free() - Free the memory of extcon device.
 624  * @edev:       the extcon device to free
 625  */
 626 void extcon_dev_free(struct extcon_dev *edev)
 627 {
 628         kfree(edev);
 629 }
 630 EXPORT_SYMBOL_GPL(extcon_dev_free);
 631
 632 static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
 633 {
 634         struct extcon_dev **r = res;
 635
 636         if (WARN_ON(!r || !*r))
 637                 return 0;
 638
 639         return *r == data;
 640 }
 641
 642 static void devm_extcon_dev_release(struct device *dev, void *res)
 643 {
 644         extcon_dev_free(*(struct extcon_dev **)res);
 645 }
 646
 647 /**
 648  * devm_extcon_dev_allocate - Allocate managed extcon device
 649  * @dev:                device owning the extcon device being created
 650  * @supported_cable:    Array of supported cable names ending with NULL.
 651  *                      If supported_cable is NULL, cable name related APIs
 652  *                      are disabled.
 653  *
 654  * This function manages automatically the memory of extcon device using device
 655  * resource management and simplify the control of freeing the memory of extcon
 656  * device.
 657  *
 658  * Returns the pointer memory of allocated extcon_dev if success
 659  * or ERR_PTR(err) if fail
 660  */
 661 struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
 662                                             const char **supported_cable)
 663 {
 664         struct extcon_dev **ptr, *edev;
 665
 666         ptr = devres_alloc(devm_extcon_dev_release, sizeof(*ptr), GFP_KERNEL);
 667         if (!ptr)
 668                 return ERR_PTR(-ENOMEM);
 669
 670         edev = extcon_dev_allocate(supported_cable);
 671         if (IS_ERR(edev)) {
 672                 devres_free(ptr);
 673                 return edev;
 674         }
 675
 676         edev->dev.parent = dev;
 677
 678         *ptr = edev;
 679         devres_add(dev, ptr);
 680
 681         return edev;
 682 }
 683 EXPORT_SYMBOL_GPL(devm_extcon_dev_allocate);
 684
 685 void devm_extcon_dev_free(struct device *dev, struct extcon_dev *edev)
 686 {
 687         WARN_ON(devres_release(dev, devm_extcon_dev_release,
 688                                devm_extcon_dev_match, edev));
 689 }
 690 EXPORT_SYMBOL_GPL(devm_extcon_dev_free);
 691
 692 /**
 693  * extcon_dev_register() - Register a new extcon device
 694  * @edev        : the new extcon device (should be allocated before calling)
 695  *
 696  * Among the members of edev struct, please set the "user initializing data"
 697  * in any case and set the "optional callbacks" if required. However, please
 698  * do not set the values of "internal data", which are initialized by
 699  * this function.
 700  */
 701 int extcon_dev_register(struct extcon_dev *edev)
 702 {
 703         int ret, index = 0;
 704         static atomic_t edev_no = ATOMIC_INIT(-1);
 705
 706         if (!extcon_class) {
 707                 ret = create_extcon_class();
 708                 if (ret < 0)
 709                         return ret;
 710         }
 711
 712         if (edev->supported_cable) {
 713                 /* Get size of array */
 714                 for (index = 0; edev->supported_cable[index]; index++)
 715                         ;
 716                 edev->max_supported = index;
 717         } else {
 718                 edev->max_supported = 0;
 719         }
 720
 721         if (index > SUPPORTED_CABLE_MAX) {
 722                 dev_err(&edev->dev, "extcon: maximum number of supported cables exceeded.\n");
 723                 return -EINVAL;
 724         }
 725
 726         edev->dev.class = extcon_class;
 727         edev->dev.release = extcon_dev_release;
 728
 729         edev->name = dev_name(edev->dev.parent);
 730         if (IS_ERR_OR_NULL(edev->name)) {
 731                 dev_err(&edev->dev,
 732                         "extcon device name is null\n");
 733                 return -EINVAL;
 734         }
 735         dev_set_name(&edev->dev, "extcon%lu",
 736                         (unsigned long)atomic_inc_return(&edev_no));
 737
 738         if (edev->max_supported) {
 739                 char buf[10];
 740                 char *str;
 741                 struct extcon_cable *cable;
 742
 743                 edev->cables = kzalloc(sizeof(struct extcon_cable) *
 744                                        edev->max_supported, GFP_KERNEL);
 745                 if (!edev->cables) {
 746                         ret = -ENOMEM;
 747                         goto err_sysfs_alloc;
 748                 }
 749                 for (index = 0; index < edev->max_supported; index++) {
 750                         cable = &edev->cables[index];
 751
 752                         snprintf(buf, 10, "cable.%d", index);
 753                         str = kzalloc(sizeof(char) * (strlen(buf) + 1),
 754                                       GFP_KERNEL);
 755                         if (!str) {
 756                                 for (index--; index >= 0; index--) {
 757                                         cable = &edev->cables[index];
 758                                         kfree(cable->attr_g.name);
 759                                 }
 760                                 ret = -ENOMEM;
 761
 762                                 goto err_alloc_cables;
 763                         }
 764                         strcpy(str, buf);
 765
 766                         cable->edev = edev;
 767                         cable->cable_index = index;
 768                         cable->attrs[0] = &cable->attr_name.attr;
 769                         cable->attrs[1] = &cable->attr_state.attr;
 770                         cable->attrs[2] = NULL;
 771                         cable->attr_g.name = str;
 772                         cable->attr_g.attrs = cable->attrs;
 773
 774                         sysfs_attr_init(&cable->attr_name.attr);
 775                         cable->attr_name.attr.name = "name";
 776                         cable->attr_name.attr.mode = 0444;
 777                         cable->attr_name.show = cable_name_show;
 778
 779                         sysfs_attr_init(&cable->attr_state.attr);
 780                         cable->attr_state.attr.name = "state";
 781                         cable->attr_state.attr.mode = 0444;
 782                         cable->attr_state.show = cable_state_show;
 783                 }
 784         }
 785
 786         if (edev->max_supported && edev->mutually_exclusive) {
 787                 char buf[80];
 788                 char *name;
 789
 790                 /* Count the size of mutually_exclusive array */
 791                 for (index = 0; edev->mutually_exclusive[index]; index++)
 792                         ;
 793
 794                 edev->attrs_muex = kzalloc(sizeof(struct attribute *) *
 795                                            (index + 1), GFP_KERNEL);
 796                 if (!edev->attrs_muex) {
 797                         ret = -ENOMEM;
 798                         goto err_muex;
 799                 }
 800
 801                 edev->d_attrs_muex = kzalloc(sizeof(struct device_attribute) *
 802                                              index, GFP_KERNEL);
 803                 if (!edev->d_attrs_muex) {
 804                         ret = -ENOMEM;
 805                         kfree(edev->attrs_muex);
 806                         goto err_muex;
 807                 }
 808
 809                 for (index = 0; edev->mutually_exclusive[index]; index++) {
 810                         sprintf(buf, "0x%x", edev->mutually_exclusive[index]);
 811                         name = kzalloc(sizeof(char) * (strlen(buf) + 1),
 812                                        GFP_KERNEL);
 813                         if (!name) {
 814                                 for (index--; index >= 0; index--) {
 815                                         kfree(edev->d_attrs_muex[index].attr.
 816                                               name);
 817                                 }
 818                                 kfree(edev->d_attrs_muex);
 819                                 kfree(edev->attrs_muex);
 820                                 ret = -ENOMEM;
 821                                 goto err_muex;
 822                         }
 823                         strcpy(name, buf);
 824                         sysfs_attr_init(&edev->d_attrs_muex[index].attr);
 825                         edev->d_attrs_muex[index].attr.name = name;
 826                         edev->d_attrs_muex[index].attr.mode = 0000;
 827                         edev->attrs_muex[index] = &edev->d_attrs_muex[index]
 828                                                         .attr;
 829                 }
 830                 edev->attr_g_muex.name = muex_name;
 831                 edev->attr_g_muex.attrs = edev->attrs_muex;
 832
 833         }
 834
 835         if (edev->max_supported) {
 836                 edev->extcon_dev_type.groups =
 837                         kzalloc(sizeof(struct attribute_group *) *
 838                                 (edev->max_supported + 2), GFP_KERNEL);
 839                 if (!edev->extcon_dev_type.groups) {
 840                         ret = -ENOMEM;
 841                         goto err_alloc_groups;
 842                 }
 843
 844                 edev->extcon_dev_type.name = dev_name(&edev->dev);
 845                 edev->extcon_dev_type.release = dummy_sysfs_dev_release;
 846
 847                 for (index = 0; index < edev->max_supported; index++)
 848                         edev->extcon_dev_type.groups[index] =
 849                                 &edev->cables[index].attr_g;
 850                 if (edev->mutually_exclusive)
 851                         edev->extcon_dev_type.groups[index] =
 852                                 &edev->attr_g_muex;
 853
 854                 edev->dev.type = &edev->extcon_dev_type;
 855         }
 856
 857         ret = device_register(&edev->dev);
 858         if (ret) {
 859                 put_device(&edev->dev);
 860                 goto err_dev;
 861         }
 862 #if defined(CONFIG_ANDROID)
 863         if (switch_class)
 864                 ret = class_compat_create_link(switch_class, &edev->dev, NULL);
 865 #endif /* CONFIG_ANDROID */
 866
 867         spin_lock_init(&edev->lock);
 868
 869         RAW_INIT_NOTIFIER_HEAD(&edev->nh);
 870
 871         dev_set_drvdata(&edev->dev, edev);
 872         edev->state = 0;
 873
 874         mutex_lock(&extcon_dev_list_lock);
 875         list_add(&edev->entry, &extcon_dev_list);
 876         mutex_unlock(&extcon_dev_list_lock);
 877
 878         return 0;
 879
 880 err_dev:
 881         if (edev->max_supported)
 882                 kfree(edev->extcon_dev_type.groups);
 883 err_alloc_groups:
 884         if (edev->max_supported && edev->mutually_exclusive) {
 885                 for (index = 0; edev->mutually_exclusive[index]; index++)
 886                         kfree(edev->d_attrs_muex[index].attr.name);
 887                 kfree(edev->d_attrs_muex);
 888                 kfree(edev->attrs_muex);
 889         }
 890 err_muex:
 891         for (index = 0; index < edev->max_supported; index++)
 892                 kfree(edev->cables[index].attr_g.name);
 893 err_alloc_cables:
 894         if (edev->max_supported)
 895                 kfree(edev->cables);
 896 err_sysfs_alloc:
 897         return ret;
 898 }
 899 EXPORT_SYMBOL_GPL(extcon_dev_register);
 900
 901 /**
 902  * extcon_dev_unregister() - Unregister the extcon device.
 903  * @edev:       the extcon device instance to be unregistered.
 904  *
 905  * Note that this does not call kfree(edev) because edev was not allocated
 906  * by this class.
 907  */
 908 void extcon_dev_unregister(struct extcon_dev *edev)
 909 {
 910         int index;
 911
 912         mutex_lock(&extcon_dev_list_lock);
 913         list_del(&edev->entry);
 914         mutex_unlock(&extcon_dev_list_lock);
 915
 916         if (IS_ERR_OR_NULL(get_device(&edev->dev))) {
 917                 dev_err(&edev->dev, "Failed to unregister extcon_dev (%s)\n",
 918                                 dev_name(&edev->dev));
 919                 return;
 920         }
 921
 922         device_unregister(&edev->dev);
 923
 924         if (edev->mutually_exclusive && edev->max_supported) {
 925                 for (index = 0; edev->mutually_exclusive[index];
 926                                 index++)
 927                         kfree(edev->d_attrs_muex[index].attr.name);
 928                 kfree(edev->d_attrs_muex);
 929                 kfree(edev->attrs_muex);
 930         }
 931
 932         for (index = 0; index < edev->max_supported; index++)
 933                 kfree(edev->cables[index].attr_g.name);
 934
 935         if (edev->max_supported) {
 936                 kfree(edev->extcon_dev_type.groups);
 937                 kfree(edev->cables);
 938         }
 939
 940 #if defined(CONFIG_ANDROID)
 941         if (switch_class)
 942                 class_compat_remove_link(switch_class, &edev->dev, NULL);
 943 #endif
 944         put_device(&edev->dev);
 945 }
 946 EXPORT_SYMBOL_GPL(extcon_dev_unregister);
 947
 948 static void devm_extcon_dev_unreg(struct device *dev, void *res)
 949 {
 950         extcon_dev_unregister(*(struct extcon_dev **)res);
 951 }
 952
 953 /**
 954  * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
 955  * @dev:        device to allocate extcon device
 956  * @edev:       the new extcon device to register
 957  *
 958  * Managed extcon_dev_register() function. If extcon device is attached with
 959  * this function, that extcon device is automatically unregistered on driver
 960  * detach. Internally this function calls extcon_dev_register() function.
 961  * To get more information, refer that function.
 962  *
 963  * If extcon device is registered with this function and the device needs to be
 964  * unregistered separately, devm_extcon_dev_unregister() should be used.
 965  *
 966  * Returns 0 if success or negaive error number if failure.
 967  */
 968 int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
 969 {
 970         struct extcon_dev **ptr;
 971         int ret;
 972
 973         ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
 974         if (!ptr)
 975                 return -ENOMEM;
 976
 977         ret = extcon_dev_register(edev);
 978         if (ret) {
 979                 devres_free(ptr);
 980                 return ret;
 981         }
 982
 983         *ptr = edev;
 984         devres_add(dev, ptr);
 985
 986         return 0;
 987 }
 988 EXPORT_SYMBOL_GPL(devm_extcon_dev_register);
 989
 990 /**
 991  * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
 992  * @dev:        device the extcon belongs to
 993  * @edev:       the extcon device to unregister
 994  *
 995  * Unregister extcon device that is registered with devm_extcon_dev_register()
 996  * function.
 997  */
 998 void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
 999 {
1000         WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
1001                                devm_extcon_dev_match, edev));
1002 }
1003 EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);
1004
1005 #ifdef CONFIG_OF
1006 /*
1007  * extcon_get_edev_by_phandle - Get the extcon device from devicetree
1008  * @dev - instance to the given device
1009  * @index - index into list of extcon_dev
1010  *
1011  * return the instance of extcon device
1012  */
1013 struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
1014 {
1015         struct device_node *node;
1016         struct extcon_dev *edev;
1017
1018         if (!dev->of_node) {
1019                 dev_err(dev, "device does not have a device node entry\n");
1020                 return ERR_PTR(-EINVAL);
1021         }
1022
1023         node = of_parse_phandle(dev->of_node, "extcon", index);
1024         if (!node) {
1025                 dev_err(dev, "failed to get phandle in %s node\n",
1026                         dev->of_node->full_name);
1027                 return ERR_PTR(-ENODEV);
1028         }
1029
1030         mutex_lock(&extcon_dev_list_lock);
1031         list_for_each_entry(edev, &extcon_dev_list, entry) {
1032                 if (edev->dev.parent && edev->dev.parent->of_node == node) {
1033                         mutex_unlock(&extcon_dev_list_lock);
1034                         return edev;
1035                 }
1036         }
1037         mutex_unlock(&extcon_dev_list_lock);
1038
1039         return ERR_PTR(-EPROBE_DEFER);
1040 }
1041 #else
1042 struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
1043 {
1044         return ERR_PTR(-ENOSYS);
1045 }
1046 #endif /* CONFIG_OF */
1047 EXPORT_SYMBOL_GPL(extcon_get_edev_by_phandle);
1048
1049 /**
1050  * extcon_get_edev_name() - Get the name of the extcon device.
1051  * @edev:       the extcon device
1052  */
1053 const char *extcon_get_edev_name(struct extcon_dev *edev)
1054 {
1055         return !edev ? NULL : edev->name;
1056 }
1057
1058 static int __init extcon_class_init(void)
1059 {
1060         return create_extcon_class();
1061 }
1062 module_init(extcon_class_init);
1063
1064 static void __exit extcon_class_exit(void)
1065 {
1066 #if defined(CONFIG_ANDROID)
1067         class_compat_unregister(switch_class);
1068 #endif
1069         class_destroy(extcon_class);
1070 }
1071 module_exit(extcon_class_exit);
1072
1073 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
1074 MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
1075 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1076 MODULE_DESCRIPTION("External connector (extcon) class driver");
1077 MODULE_LICENSE("GPL");