drivers/extcon/extcon.c

   1 /*
   2  *  drivers/extcon/extcon.c - External Connector (extcon) framework.
   3  *
   4  *  External connector (extcon) class driver
   5  *
   6  * Copyright (C) 2015 Samsung Electronics
   7  * Author: Chanwoo Choi <cw00.choi@samsung.com>
   8  *
   9  * Copyright (C) 2012 Samsung Electronics
  10  * Author: Donggeun Kim <dg77.kim@samsung.com>
  11  * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
  12  *
  13  * based on android/drivers/switch/switch_class.c
  14  * Copyright (C) 2008 Google, Inc.
  15  * Author: Mike Lockwood <lockwood@android.com>
  16  *
  17  * This software is licensed under the terms of the GNU General Public
  18  * License version 2, as published by the Free Software Foundation, and
  19  * may be copied, distributed, and modified under those terms.
  20  *
  21  * This program is distributed in the hope that it will be useful,
  22  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  23  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  24  * GNU General Public License for more details.
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/types.h>
  29 #include <linux/init.h>
  30 #include <linux/device.h>
  31 #include <linux/fs.h>
  32 #include <linux/err.h>
  33 #include <linux/extcon.h>
  34 #include <linux/of.h>
  35 #include <linux/slab.h>
  36 #include <linux/sysfs.h>
  37
  38 #define SUPPORTED_CABLE_MAX     32
  39 #define CABLE_NAME_MAX          30
  40
  41 static const char *extcon_name[] =  {
  42         [EXTCON_NONE]           = "NONE",
  43
  44         /* USB external connector */
  45         [EXTCON_USB]            = "USB",
  46         [EXTCON_USB_HOST]       = "USB-HOST",
  47
  48         /* Charger external connector */
  49         [EXTCON_TA]             = "TA",
  50         [EXTCON_FAST_CHARGER]   = "FAST-CHARGER",
  51         [EXTCON_SLOW_CHARGER]   = "SLOW-CHARGER",
  52         [EXTCON_CHARGE_DOWNSTREAM] = "CHARGE-DOWNSTREAM",
  53
  54         /* Audio/Video external connector */
  55         [EXTCON_LINE_IN]        = "LINE-IN",
  56         [EXTCON_LINE_OUT]       = "LINE-OUT",
  57         [EXTCON_MICROPHONE]     = "MICROPHONE",
  58         [EXTCON_HEADPHONE]      = "HEADPHONE",
  59
  60         [EXTCON_HDMI]           = "HDMI",
  61         [EXTCON_MHL]            = "MHL",
  62         [EXTCON_DVI]            = "DVI",
  63         [EXTCON_VGA]            = "VGA",
  64         [EXTCON_SPDIF_IN]       = "SPDIF-IN",
  65         [EXTCON_SPDIF_OUT]      = "SPDIF-OUT",
  66         [EXTCON_VIDEO_IN]       = "VIDEO-IN",
  67         [EXTCON_VIDEO_OUT]      = "VIDEO-OUT",
  68
  69         /* Etc external connector */
  70         [EXTCON_DOCK]           = "DOCK",
  71         [EXTCON_JIG]            = "JIG",
  72         [EXTCON_MECHANICAL]     = "MECHANICAL",
  73
  74         NULL,
  75 };
  76
  77 static struct class *extcon_class;
  78 #if defined(CONFIG_ANDROID)
  79 static struct class_compat *switch_class;
  80 #endif /* CONFIG_ANDROID */
  81
  82 static LIST_HEAD(extcon_dev_list);
  83 static DEFINE_MUTEX(extcon_dev_list_lock);
  84
  85 /**
  86  * check_mutually_exclusive - Check if new_state violates mutually_exclusive
  87  *                            condition.
  88  * @edev:       the extcon device
  89  * @new_state:  new cable attach status for @edev
  90  *
  91  * Returns 0 if nothing violates. Returns the index + 1 for the first
  92  * violated condition.
  93  */
  94 static int check_mutually_exclusive(struct extcon_dev *edev, u32 new_state)
  95 {
  96         int i = 0;
  97
  98         if (!edev->mutually_exclusive)
  99                 return 0;
 100
 101         for (i = 0; edev->mutually_exclusive[i]; i++) {
 102                 int weight;
 103                 u32 correspondants = new_state & edev->mutually_exclusive[i];
 104
 105                 /* calculate the total number of bits set */
 106                 weight = hweight32(correspondants);
 107                 if (weight > 1)
 108                         return i + 1;
 109         }
 110
 111         return 0;
 112 }
 113
 114 static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id)
 115 {
 116         int i;
 117
 118         /* Find the the index of extcon cable in edev->supported_cable */
 119         for (i = 0; i < edev->max_supported; i++) {
 120                 if (edev->supported_cable[i] == id)
 121                         return i;
 122         }
 123
 124         return -EINVAL;
 125 }
 126
 127 static int find_cable_id_by_name(struct extcon_dev *edev, const char *name)
 128 {
 129         unsigned int id = -EINVAL;
 130         int i = 0;
 131
 132         /* Find the id of extcon cable */
 133         while (extcon_name[i]) {
 134                 if (!strncmp(extcon_name[i], name, CABLE_NAME_MAX)) {
 135                         id = i;
 136                         break;
 137                 }
 138                 i++;
 139         }
 140
 141         return id;
 142 }
 143
 144 static int find_cable_index_by_name(struct extcon_dev *edev, const char *name)
 145 {
 146         unsigned int id;
 147
 148         if (edev->max_supported == 0)
 149                 return -EINVAL;
 150
 151         /* Find the the number of extcon cable */
 152         id = find_cable_id_by_name(edev, name);
 153         if (id < 0)
 154                 return id;
 155
 156         return find_cable_index_by_id(edev, id);
 157 }
 158
 159 static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
 160 {
 161         if (((prev >> idx) & 0x1) != ((new >> idx) & 0x1)) {
 162                 *attached = new ? true : false;
 163                 return true;
 164         }
 165
 166         return false;
 167 }
 168
 169 static ssize_t state_show(struct device *dev, struct device_attribute *attr,
 170                           char *buf)
 171 {
 172         int i, count = 0;
 173         struct extcon_dev *edev = dev_get_drvdata(dev);
 174
 175         if (edev->max_supported == 0)
 176                 return sprintf(buf, "%u\n", edev->state);
 177
 178         for (i = 0; i < edev->max_supported; i++) {
 179                 count += sprintf(buf + count, "%s=%d\n",
 180                                 extcon_name[edev->supported_cable[i]],
 181                                  !!(edev->state & (1 << i)));
 182         }
 183
 184         return count;
 185 }
 186
 187 static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 188                            const char *buf, size_t count)
 189 {
 190         u32 state;
 191         ssize_t ret = 0;
 192         struct extcon_dev *edev = dev_get_drvdata(dev);
 193
 194         ret = sscanf(buf, "0x%x", &state);
 195         if (ret == 0)
 196                 ret = -EINVAL;
 197         else
 198                 ret = extcon_set_state(edev, state);
 199
 200         if (ret < 0)
 201                 return ret;
 202
 203         return count;
 204 }
 205 static DEVICE_ATTR_RW(state);
 206
 207 static ssize_t name_show(struct device *dev, struct device_attribute *attr,
 208                 char *buf)
 209 {
 210         struct extcon_dev *edev = dev_get_drvdata(dev);
 211
 212         return sprintf(buf, "%s\n", edev->name);
 213 }
 214 static DEVICE_ATTR_RO(name);
 215
 216 static ssize_t cable_name_show(struct device *dev,
 217                                struct device_attribute *attr, char *buf)
 218 {
 219         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 220                                                   attr_name);
 221         int i = cable->cable_index;
 222
 223         return sprintf(buf, "%s\n",
 224                         extcon_name[cable->edev->supported_cable[i]]);
 225 }
 226
 227 static ssize_t cable_state_show(struct device *dev,
 228                                 struct device_attribute *attr, char *buf)
 229 {
 230         struct extcon_cable *cable = container_of(attr, struct extcon_cable,
 231                                                   attr_state);
 232
 233         int i = cable->cable_index;
 234
 235         return sprintf(buf, "%d\n",
 236                        extcon_get_cable_state_(cable->edev,
 237                                                cable->edev->supported_cable[i]));
 238 }
 239
 240 /**
 241  * extcon_update_state() - Update the cable attach states of the extcon device
 242  *                         only for the masked bits.
 243  * @edev:       the extcon device
 244  * @mask:       the bit mask to designate updated bits.
 245  * @state:      new cable attach status for @edev
 246  *
 247  * Changing the state sends uevent with environment variable containing
 248  * the name of extcon device (envp[0]) and the state output (envp[1]).
 249  * Tizen uses this format for extcon device to get events from ports.
 250  * Android uses this format as well.
 251  *
 252  * Note that the notifier provides which bits are changed in the state
 253  * variable with the val parameter (second) to the callback.
 254  */
 255 int extcon_update_state(struct extcon_dev *edev, u32 mask, u32 state)
 256 {
 257         char name_buf[120];
 258         char state_buf[120];
 259         char *prop_buf;
 260         char *envp[3];
 261         int env_offset = 0;
 262         int length;
 263         int index;
 264         unsigned long flags;
 265         bool attached;
 266
 267         spin_lock_irqsave(&edev->lock, flags);
 268
 269         if (edev->state != ((edev->state & ~mask) | (state & mask))) {
 270                 u32 old_state;
 271
 272                 if (check_mutually_exclusive(edev, (edev->state & ~mask) |
 273                                                    (state & mask))) {
 274                         spin_unlock_irqrestore(&edev->lock, flags);
 275                         return -EPERM;
 276                 }
 277
 278                 old_state = edev->state;
 279                 edev->state &= ~mask;
 280                 edev->state |= state & mask;
 281
 282                 for (index = 0; index < edev->max_supported; index++) {
 283                         if (is_extcon_changed(old_state, edev->state, index,
 284                                               &attached))
 285                                 raw_notifier_call_chain(&edev->nh[index],
 286                                                         attached, edev);
 287                 }
 288
 289                 /* This could be in interrupt handler */
 290                 prop_buf = (char *)get_zeroed_page(GFP_ATOMIC);
 291                 if (prop_buf) {
 292                         length = name_show(&edev->dev, NULL, prop_buf);
 293                         if (length > 0) {
 294                                 if (prop_buf[length - 1] == '\n')
 295                                         prop_buf[length - 1] = 0;
 296                                 snprintf(name_buf, sizeof(name_buf),
 297                                         "NAME=%s", prop_buf);
 298                                 envp[env_offset++] = name_buf;
 299                         }
 300                         length = state_show(&edev->dev, NULL, prop_buf);
 301                         if (length > 0) {
 302                                 if (prop_buf[length - 1] == '\n')
 303                                         prop_buf[length - 1] = 0;
 304                                 snprintf(state_buf, sizeof(state_buf),
 305                                         "STATE=%s", prop_buf);
 306                                 envp[env_offset++] = state_buf;
 307                         }
 308                         envp[env_offset] = NULL;
 309                         /* Unlock early before uevent */
 310                         spin_unlock_irqrestore(&edev->lock, flags);
 311
 312                         kobject_uevent_env(&edev->dev.kobj, KOBJ_CHANGE, envp);
 313                         free_page((unsigned long)prop_buf);
 314                 } else {
 315                         /* Unlock early before uevent */
 316                         spin_unlock_irqrestore(&edev->lock, flags);
 317
 318                         dev_err(&edev->dev, "out of memory in extcon_set_state\n");
 319                         kobject_uevent(&edev->dev.kobj, KOBJ_CHANGE);
 320                 }
 321         } else {
 322                 /* No changes */
 323                 spin_unlock_irqrestore(&edev->lock, flags);
 324         }
 325
 326         return 0;
 327 }
 328 EXPORT_SYMBOL_GPL(extcon_update_state);
 329
 330 /**
 331  * extcon_set_state() - Set the cable attach states of the extcon device.
 332  * @edev:       the extcon device
 333  * @state:      new cable attach status for @edev
 334  *
 335  * Note that notifier provides which bits are changed in the state
 336  * variable with the val parameter (second) to the callback.
 337  */
 338 int extcon_set_state(struct extcon_dev *edev, u32 state)
 339 {
 340         return extcon_update_state(edev, 0xffffffff, state);
 341 }
 342 EXPORT_SYMBOL_GPL(extcon_set_state);
 343
 344 /**
 345  * extcon_get_cable_state_() - Get the status of a specific cable.
 346  * @edev:       the extcon device that has the cable.
 347  * @id:         the unique id of each external connector in extcon enumeration.
 348  */
 349 int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
 350 {
 351         int index;
 352
 353         index = find_cable_index_by_id(edev, id);
 354         if (index < 0)
 355                 return index;
 356
 357         if (edev->max_supported && edev->max_supported <= index)
 358                 return -EINVAL;
 359
 360         return !!(edev->state & (1 << index));
 361 }
 362 EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
 363
 364 /**
 365  * extcon_get_cable_state() - Get the status of a specific cable.
 366  * @edev:       the extcon device that has the cable.
 367  * @cable_name: cable name.
 368  *
 369  * Note that this is slower than extcon_get_cable_state_.
 370  */
 371 int extcon_get_cable_state(struct extcon_dev *edev, const char *cable_name)
 372 {
 373         unsigned int id;
 374
 375         id = find_cable_id_by_name(edev, cable_name);
 376         if (id < 0)
 377                 return id;
 378
 379         return extcon_get_cable_state_(edev, id);
 380 }
 381 EXPORT_SYMBOL_GPL(extcon_get_cable_state);
 382
 383 /**
 384  * extcon_set_cable_state_() - Set the status of a specific cable.
 385  * @edev:               the extcon device that has the cable.
 386  * @id:                 the unique id of each external connector
 387  *                      in extcon enumeration.
 388  * @state:              the new cable status. The default semantics is
 389  *                      true: attached / false: detached.
 390  */
 391 int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
 392                                 bool cable_state)
 393 {
 394         u32 state;
 395         int index;
 396
 397         index = find_cable_index_by_id(edev, id);
 398         if (index < 0)
 399                 return index;
 400
 401         if (edev->max_supported && edev->max_supported <= index)
 402                 return -EINVAL;
 403
 404         state = cable_state ? (1 << index) : 0;
 405         return extcon_update_state(edev, 1 << index, state);
 406 }
 407 EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
 408
 409 /**
 410  * extcon_set_cable_state() - Set the status of a specific cable.
 411  * @edev:               the extcon device that has the cable.
 412  * @cable_name:         cable name.
 413  * @cable_state:        the new cable status. The default semantics is
 414  *                      true: attached / false: detached.
 415  *
 416  * Note that this is slower than extcon_set_cable_state_.
 417  */
 418 int extcon_set_cable_state(struct extcon_dev *edev,
 419                         const char *cable_name, bool cable_state)
 420 {
 421         unsigned int id;
 422
 423         id = find_cable_id_by_name(edev, cable_name);
 424         if (id < 0)
 425                 return id;
 426
 427         return extcon_set_cable_state_(edev, id, cable_state);
 428 }
 429 EXPORT_SYMBOL_GPL(extcon_set_cable_state);
 430
 431 /**
 432  * extcon_get_extcon_dev() - Get the extcon device instance from the name
 433  * @extcon_name:        The extcon name provided with extcon_dev_register()
 434  */
 435 struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
 436 {
 437         struct extcon_dev *sd;
 438
 439         mutex_lock(&extcon_dev_list_lock);
 440         list_for_each_entry(sd, &extcon_dev_list, entry) {
 441                 if (!strcmp(sd->name, extcon_name))
 442                         goto out;
 443         }
 444         sd = NULL;
 445 out:
 446         mutex_unlock(&extcon_dev_list_lock);
 447         return sd;
 448 }
 449 EXPORT_SYMBOL_GPL(extcon_get_extcon_dev);
 450
 451 /**
 452  * extcon_register_interest() - Register a notifier for a state change of a
 453  *                              specific cable, not an entier set of cables of a
 454  *                              extcon device.
 455  * @obj:                an empty extcon_specific_cable_nb object to be returned.
 456  * @extcon_name:        the name of extcon device.
 457  *                      if NULL, extcon_register_interest will register
 458  *                      every cable with the target cable_name given.
 459  * @cable_name:         the target cable name.
 460  * @nb:                 the notifier block to get notified.
 461  *
 462  * Provide an empty extcon_specific_cable_nb. extcon_register_interest() sets
 463  * the struct for you.
 464  *
 465  * extcon_register_interest is a helper function for those who want to get
 466  * notification for a single specific cable's status change. If a user wants
 467  * to get notification for any changes of all cables of a extcon device,
 468  * he/she should use the general extcon_register_notifier().
 469  *
 470  * Note that the second parameter given to the callback of nb (val) is
 471  * "old_state", not the current state. The current state can be retrieved
 472  * by looking at the third pameter (edev pointer)'s state value.
 473  */
 474 int extcon_register_interest(struct extcon_specific_cable_nb *obj,
 475                              const char *extcon_name, const char *cable_name,
 476                              struct notifier_block *nb)
 477 {
 478         unsigned long flags;
 479         int ret;
 480
 481         if (!obj || !cable_name || !nb)
 482                 return -EINVAL;
 483
 484         if (extcon_name) {
 485                 obj->edev = extcon_get_extcon_dev(extcon_name);
 486                 if (!obj->edev)
 487                         return -ENODEV;
 488
 489                 obj->cable_index = find_cable_index_by_name(obj->edev,
 490                                                         cable_name);
 491                 if (obj->cable_index < 0)
 492                         return obj->cable_index;
 493
 494                 obj->user_nb = nb;
 495
 496                 spin_lock_irqsave(&obj->edev->lock, flags);
 497                 ret = raw_notifier_chain_register(
 498                                         &obj->edev->nh[obj->cable_index],
 499                                         obj->user_nb);
 500                 spin_unlock_irqrestore(&obj->edev->lock, flags);
 501         } else {
 502                 struct class_dev_iter iter;
 503                 struct extcon_dev *extd;
 504                 struct device *dev;
 505
 506                 if (!extcon_class)
 507                         return -ENODEV;
 508                 class_dev_iter_init(&iter, extcon_class, NULL, NULL);
 509                 while ((dev = class_dev_iter_next(&iter))) {
 510                         extd = dev_get_drvdata(dev);
 511
 512                         if (find_cable_index_by_name(extd, cable_name) < 0)
 513                                 continue;
 514
 515                         class_dev_iter_exit(&iter);
 516                         return extcon_register_interest(obj, extd->name,
 517                                                 cable_name, nb);
 518                 }
 519
 520                 ret = -ENODEV;
 521         }
 522
 523         return ret;
 524 }
 525 EXPORT_SYMBOL_GPL(extcon_register_interest);
 526
 527 /**
 528  * extcon_unregister_interest() - Unregister the notifier registered by
 529  *                                extcon_register_interest().
 530  * @obj:        the extcon_specific_cable_nb object returned by
 531  *              extcon_register_interest().
 532  */
 533 int extcon_unregister_interest(struct extcon_specific_cable_nb *obj)
 534 {
 535         unsigned long flags;
 536         int ret;
 537
 538         if (!obj)
 539                 return -EINVAL;
 540
 541         spin_lock_irqsave(&obj->edev->lock, flags);
 542         ret = raw_notifier_chain_unregister(
 543                         &obj->edev->nh[obj->cable_index], obj->user_nb);
 544         spin_unlock_irqrestore(&obj->edev->lock, flags);
 545
 546         return ret;
 547 }
 548 EXPORT_SYMBOL_GPL(extcon_unregister_interest);
 549
 550 /**
 551  * extcon_register_notifier() - Register a notifiee to get notified by
 552  *                              any attach status changes from the extcon.
 553  * @edev:       the extcon device that has the external connecotr.
 554  * @id:         the unique id of each external connector in extcon enumeration.
 555  * @nb:         a notifier block to be registered.
 556  *
 557  * Note that the second parameter given to the callback of nb (val) is
 558  * "old_state", not the current state. The current state can be retrieved
 559  * by looking at the third pameter (edev pointer)'s state value.
 560  */
 561 int extcon_register_notifier(struct extcon_dev *edev, unsigned int id,
 562                              struct notifier_block *nb)
 563 {
 564         unsigned long flags;
 565         int ret, idx;
 566
 567         idx = find_cable_index_by_id(edev, id);
 568
 569         spin_lock_irqsave(&edev->lock, flags);
 570         ret = raw_notifier_chain_register(&edev->nh[idx], nb);
 571         spin_unlock_irqrestore(&edev->lock, flags);
 572
 573         return ret;
 574 }
 575 EXPORT_SYMBOL_GPL(extcon_register_notifier);
 576
 577 /**
 578  * extcon_unregister_notifier() - Unregister a notifiee from the extcon device.
 579  * @edev:       the extcon device that has the external connecotr.
 580  * @id:         the unique id of each external connector in extcon enumeration.
 581  * @nb:         a notifier block to be registered.
 582  */
 583 int extcon_unregister_notifier(struct extcon_dev *edev, unsigned int id,
 584                                 struct notifier_block *nb)
 585 {
 586         unsigned long flags;
 587         int ret, idx;
 588
 589         idx = find_cable_index_by_id(edev, id);
 590
 591         spin_lock_irqsave(&edev->lock, flags);
 592         ret = raw_notifier_chain_unregister(&edev->nh[idx], nb);
 593         spin_unlock_irqrestore(&edev->lock, flags);
 594
 595         return ret;
 596 }
 597 EXPORT_SYMBOL_GPL(extcon_unregister_notifier);
 598
 599 static struct attribute *extcon_attrs[] = {
 600         &dev_attr_state.attr,
 601         &dev_attr_name.attr,
 602         NULL,
 603 };
 604 ATTRIBUTE_GROUPS(extcon);
 605
 606 static int create_extcon_class(void)
 607 {
 608         if (!extcon_class) {
 609                 extcon_class = class_create(THIS_MODULE, "extcon");
 610                 if (IS_ERR(extcon_class))
 611                         return PTR_ERR(extcon_class);
 612                 extcon_class->dev_groups = extcon_groups;
 613
 614 #if defined(CONFIG_ANDROID)
 615                 switch_class = class_compat_register("switch");
 616                 if (WARN(!switch_class, "cannot allocate"))
 617                         return -ENOMEM;
 618 #endif /* CONFIG_ANDROID */
 619         }
 620
 621         return 0;
 622 }
 623
 624 static void extcon_dev_release(struct device *dev)
 625 {
 626 }
 627
 628 static const char *muex_name = "mutually_exclusive";
 629 static void dummy_sysfs_dev_release(struct device *dev)
 630 {
 631 }
 632
 633 /*
 634  * extcon_dev_allocate() - Allocate the memory of extcon device.
 635  * @supported_cable:    Array of supported extcon ending with EXTCON_NONE.
 636  *                      If supported_cable is NULL, cable name related APIs
 637  *                      are disabled.
 638  *
 639  * This function allocates the memory for extcon device without allocating
 640  * memory in each extcon provider driver and initialize default setting for
 641  * extcon device.
 642  *
 643  * Return the pointer of extcon device if success or ERR_PTR(err) if fail
 644  */
 645 struct extcon_dev *extcon_dev_allocate(const unsigned int *supported_cable)
 646 {
 647         struct extcon_dev *edev;
 648
 649         edev = kzalloc(sizeof(*edev), GFP_KERNEL);
 650         if (!edev)
 651                 return ERR_PTR(-ENOMEM);
 652
 653         edev->max_supported = 0;
 654         edev->supported_cable = supported_cable;
 655
 656         return edev;
 657 }
 658
 659 /*
 660  * extcon_dev_free() - Free the memory of extcon device.
 661  * @edev:       the extcon device to free
 662  */
 663 void extcon_dev_free(struct extcon_dev *edev)
 664 {
 665         kfree(edev);
 666 }
 667 EXPORT_SYMBOL_GPL(extcon_dev_free);
 668
 669 static int devm_extcon_dev_match(struct device *dev, void *res, void *data)
 670 {
 671         struct extcon_dev **r = res;
 672
 673         if (WARN_ON(!r || !*r))
 674                 return 0;
 675
 676         return *r == data;
 677 }
 678
 679 static void devm_extcon_dev_release(struct device *dev, void *res)
 680 {
 681         extcon_dev_free(*(struct extcon_dev **)res);
 682 }
 683
 684 /**
 685  * devm_extcon_dev_allocate - Allocate managed extcon device
 686  * @dev:                device owning the extcon device being created
 687  * @supported_cable:    Array of supported extcon ending with EXTCON_NONE.
 688  *                      If supported_cable is NULL, cable name related APIs
 689  *                      are disabled.
 690  *
 691  * This function manages automatically the memory of extcon device using device
 692  * resource management and simplify the control of freeing the memory of extcon
 693  * device.
 694  *
 695  * Returns the pointer memory of allocated extcon_dev if success
 696  * or ERR_PTR(err) if fail
 697  */
 698 struct extcon_dev *devm_extcon_dev_allocate(struct device *dev,
 699                                         const unsigned int *supported_cable)
 700 {
 701         struct extcon_dev **ptr, *edev;
 702
 703         ptr = devres_alloc(devm_extcon_dev_release, sizeof(*ptr), GFP_KERNEL);
 704         if (!ptr)
 705                 return ERR_PTR(-ENOMEM);
 706
 707         edev = extcon_dev_allocate(supported_cable);
 708         if (IS_ERR(edev)) {
 709                 devres_free(ptr);
 710                 return edev;
 711         }
 712
 713         edev->dev.parent = dev;
 714
 715         *ptr = edev;
 716         devres_add(dev, ptr);
 717
 718         return edev;
 719 }
 720 EXPORT_SYMBOL_GPL(devm_extcon_dev_allocate);
 721
 722 void devm_extcon_dev_free(struct device *dev, struct extcon_dev *edev)
 723 {
 724         WARN_ON(devres_release(dev, devm_extcon_dev_release,
 725                                devm_extcon_dev_match, edev));
 726 }
 727 EXPORT_SYMBOL_GPL(devm_extcon_dev_free);
 728
 729 /**
 730  * extcon_dev_register() - Register a new extcon device
 731  * @edev        : the new extcon device (should be allocated before calling)
 732  *
 733  * Among the members of edev struct, please set the "user initializing data"
 734  * in any case and set the "optional callbacks" if required. However, please
 735  * do not set the values of "internal data", which are initialized by
 736  * this function.
 737  */
 738 int extcon_dev_register(struct extcon_dev *edev)
 739 {
 740         int ret, index = 0;
 741         static atomic_t edev_no = ATOMIC_INIT(-1);
 742
 743         if (!extcon_class) {
 744                 ret = create_extcon_class();
 745                 if (ret < 0)
 746                         return ret;
 747         }
 748
 749         if (!edev->supported_cable)
 750                 return -EINVAL;
 751
 752         for (; edev->supported_cable[index] != EXTCON_NONE; index++);
 753
 754         edev->max_supported = index;
 755         if (index > SUPPORTED_CABLE_MAX) {
 756                 dev_err(&edev->dev,
 757                         "exceed the maximum number of supported cables\n");
 758                 return -EINVAL;
 759         }
 760
 761         edev->dev.class = extcon_class;
 762         edev->dev.release = extcon_dev_release;
 763
 764         edev->name = dev_name(edev->dev.parent);
 765         if (IS_ERR_OR_NULL(edev->name)) {
 766                 dev_err(&edev->dev,
 767                         "extcon device name is null\n");
 768                 return -EINVAL;
 769         }
 770         dev_set_name(&edev->dev, "extcon%lu",
 771                         (unsigned long)atomic_inc_return(&edev_no));
 772
 773         if (edev->max_supported) {
 774                 char buf[10];
 775                 char *str;
 776                 struct extcon_cable *cable;
 777
 778                 edev->cables = kzalloc(sizeof(struct extcon_cable) *
 779                                        edev->max_supported, GFP_KERNEL);
 780                 if (!edev->cables) {
 781                         ret = -ENOMEM;
 782                         goto err_sysfs_alloc;
 783                 }
 784                 for (index = 0; index < edev->max_supported; index++) {
 785                         cable = &edev->cables[index];
 786
 787                         snprintf(buf, 10, "cable.%d", index);
 788                         str = kzalloc(sizeof(char) * (strlen(buf) + 1),
 789                                       GFP_KERNEL);
 790                         if (!str) {
 791                                 for (index--; index >= 0; index--) {
 792                                         cable = &edev->cables[index];
 793                                         kfree(cable->attr_g.name);
 794                                 }
 795                                 ret = -ENOMEM;
 796
 797                                 goto err_alloc_cables;
 798                         }
 799                         strcpy(str, buf);
 800
 801                         cable->edev = edev;
 802                         cable->cable_index = index;
 803                         cable->attrs[0] = &cable->attr_name.attr;
 804                         cable->attrs[1] = &cable->attr_state.attr;
 805                         cable->attrs[2] = NULL;
 806                         cable->attr_g.name = str;
 807                         cable->attr_g.attrs = cable->attrs;
 808
 809                         sysfs_attr_init(&cable->attr_name.attr);
 810                         cable->attr_name.attr.name = "name";
 811                         cable->attr_name.attr.mode = 0444;
 812                         cable->attr_name.show = cable_name_show;
 813
 814                         sysfs_attr_init(&cable->attr_state.attr);
 815                         cable->attr_state.attr.name = "state";
 816                         cable->attr_state.attr.mode = 0444;
 817                         cable->attr_state.show = cable_state_show;
 818                 }
 819         }
 820
 821         if (edev->max_supported && edev->mutually_exclusive) {
 822                 char buf[80];
 823                 char *name;
 824
 825                 /* Count the size of mutually_exclusive array */
 826                 for (index = 0; edev->mutually_exclusive[index]; index++)
 827                         ;
 828
 829                 edev->attrs_muex = kzalloc(sizeof(struct attribute *) *
 830                                            (index + 1), GFP_KERNEL);
 831                 if (!edev->attrs_muex) {
 832                         ret = -ENOMEM;
 833                         goto err_muex;
 834                 }
 835
 836                 edev->d_attrs_muex = kzalloc(sizeof(struct device_attribute) *
 837                                              index, GFP_KERNEL);
 838                 if (!edev->d_attrs_muex) {
 839                         ret = -ENOMEM;
 840                         kfree(edev->attrs_muex);
 841                         goto err_muex;
 842                 }
 843
 844                 for (index = 0; edev->mutually_exclusive[index]; index++) {
 845                         sprintf(buf, "0x%x", edev->mutually_exclusive[index]);
 846                         name = kzalloc(sizeof(char) * (strlen(buf) + 1),
 847                                        GFP_KERNEL);
 848                         if (!name) {
 849                                 for (index--; index >= 0; index--) {
 850                                         kfree(edev->d_attrs_muex[index].attr.
 851                                               name);
 852                                 }
 853                                 kfree(edev->d_attrs_muex);
 854                                 kfree(edev->attrs_muex);
 855                                 ret = -ENOMEM;
 856                                 goto err_muex;
 857                         }
 858                         strcpy(name, buf);
 859                         sysfs_attr_init(&edev->d_attrs_muex[index].attr);
 860                         edev->d_attrs_muex[index].attr.name = name;
 861                         edev->d_attrs_muex[index].attr.mode = 0000;
 862                         edev->attrs_muex[index] = &edev->d_attrs_muex[index]
 863                                                         .attr;
 864                 }
 865                 edev->attr_g_muex.name = muex_name;
 866                 edev->attr_g_muex.attrs = edev->attrs_muex;
 867
 868         }
 869
 870         if (edev->max_supported) {
 871                 edev->extcon_dev_type.groups =
 872                         kzalloc(sizeof(struct attribute_group *) *
 873                                 (edev->max_supported + 2), GFP_KERNEL);
 874                 if (!edev->extcon_dev_type.groups) {
 875                         ret = -ENOMEM;
 876                         goto err_alloc_groups;
 877                 }
 878
 879                 edev->extcon_dev_type.name = dev_name(&edev->dev);
 880                 edev->extcon_dev_type.release = dummy_sysfs_dev_release;
 881
 882                 for (index = 0; index < edev->max_supported; index++)
 883                         edev->extcon_dev_type.groups[index] =
 884                                 &edev->cables[index].attr_g;
 885                 if (edev->mutually_exclusive)
 886                         edev->extcon_dev_type.groups[index] =
 887                                 &edev->attr_g_muex;
 888
 889                 edev->dev.type = &edev->extcon_dev_type;
 890         }
 891
 892         ret = device_register(&edev->dev);
 893         if (ret) {
 894                 put_device(&edev->dev);
 895                 goto err_dev;
 896         }
 897 #if defined(CONFIG_ANDROID)
 898         if (switch_class)
 899                 ret = class_compat_create_link(switch_class, &edev->dev, NULL);
 900 #endif /* CONFIG_ANDROID */
 901
 902         spin_lock_init(&edev->lock);
 903
 904         edev->nh = devm_kzalloc(&edev->dev,
 905                         sizeof(*edev->nh) * edev->max_supported, GFP_KERNEL);
 906         if (!edev->nh) {
 907                 ret = -ENOMEM;
 908                 goto err_dev;
 909         }
 910
 911         for (index = 0; index < edev->max_supported; index++)
 912                 RAW_INIT_NOTIFIER_HEAD(&edev->nh[index]);
 913
 914         dev_set_drvdata(&edev->dev, edev);
 915         edev->state = 0;
 916
 917         mutex_lock(&extcon_dev_list_lock);
 918         list_add(&edev->entry, &extcon_dev_list);
 919         mutex_unlock(&extcon_dev_list_lock);
 920
 921         return 0;
 922
 923 err_dev:
 924         if (edev->max_supported)
 925                 kfree(edev->extcon_dev_type.groups);
 926 err_alloc_groups:
 927         if (edev->max_supported && edev->mutually_exclusive) {
 928                 for (index = 0; edev->mutually_exclusive[index]; index++)
 929                         kfree(edev->d_attrs_muex[index].attr.name);
 930                 kfree(edev->d_attrs_muex);
 931                 kfree(edev->attrs_muex);
 932         }
 933 err_muex:
 934         for (index = 0; index < edev->max_supported; index++)
 935                 kfree(edev->cables[index].attr_g.name);
 936 err_alloc_cables:
 937         if (edev->max_supported)
 938                 kfree(edev->cables);
 939 err_sysfs_alloc:
 940         return ret;
 941 }
 942 EXPORT_SYMBOL_GPL(extcon_dev_register);
 943
 944 /**
 945  * extcon_dev_unregister() - Unregister the extcon device.
 946  * @edev:       the extcon device instance to be unregistered.
 947  *
 948  * Note that this does not call kfree(edev) because edev was not allocated
 949  * by this class.
 950  */
 951 void extcon_dev_unregister(struct extcon_dev *edev)
 952 {
 953         int index;
 954
 955         mutex_lock(&extcon_dev_list_lock);
 956         list_del(&edev->entry);
 957         mutex_unlock(&extcon_dev_list_lock);
 958
 959         if (IS_ERR_OR_NULL(get_device(&edev->dev))) {
 960                 dev_err(&edev->dev, "Failed to unregister extcon_dev (%s)\n",
 961                                 dev_name(&edev->dev));
 962                 return;
 963         }
 964
 965         device_unregister(&edev->dev);
 966
 967         if (edev->mutually_exclusive && edev->max_supported) {
 968                 for (index = 0; edev->mutually_exclusive[index];
 969                                 index++)
 970                         kfree(edev->d_attrs_muex[index].attr.name);
 971                 kfree(edev->d_attrs_muex);
 972                 kfree(edev->attrs_muex);
 973         }
 974
 975         for (index = 0; index < edev->max_supported; index++)
 976                 kfree(edev->cables[index].attr_g.name);
 977
 978         if (edev->max_supported) {
 979                 kfree(edev->extcon_dev_type.groups);
 980                 kfree(edev->cables);
 981         }
 982
 983 #if defined(CONFIG_ANDROID)
 984         if (switch_class)
 985                 class_compat_remove_link(switch_class, &edev->dev, NULL);
 986 #endif
 987         put_device(&edev->dev);
 988 }
 989 EXPORT_SYMBOL_GPL(extcon_dev_unregister);
 990
 991 static void devm_extcon_dev_unreg(struct device *dev, void *res)
 992 {
 993         extcon_dev_unregister(*(struct extcon_dev **)res);
 994 }
 995
 996 /**
 997  * devm_extcon_dev_register() - Resource-managed extcon_dev_register()
 998  * @dev:        device to allocate extcon device
 999  * @edev:       the new extcon device to register
1000  *
1001  * Managed extcon_dev_register() function. If extcon device is attached with
1002  * this function, that extcon device is automatically unregistered on driver
1003  * detach. Internally this function calls extcon_dev_register() function.
1004  * To get more information, refer that function.
1005  *
1006  * If extcon device is registered with this function and the device needs to be
1007  * unregistered separately, devm_extcon_dev_unregister() should be used.
1008  *
1009  * Returns 0 if success or negaive error number if failure.
1010  */
1011 int devm_extcon_dev_register(struct device *dev, struct extcon_dev *edev)
1012 {
1013         struct extcon_dev **ptr;
1014         int ret;
1015
1016         ptr = devres_alloc(devm_extcon_dev_unreg, sizeof(*ptr), GFP_KERNEL);
1017         if (!ptr)
1018                 return -ENOMEM;
1019
1020         ret = extcon_dev_register(edev);
1021         if (ret) {
1022                 devres_free(ptr);
1023                 return ret;
1024         }
1025
1026         *ptr = edev;
1027         devres_add(dev, ptr);
1028
1029         return 0;
1030 }
1031 EXPORT_SYMBOL_GPL(devm_extcon_dev_register);
1032
1033 /**
1034  * devm_extcon_dev_unregister() - Resource-managed extcon_dev_unregister()
1035  * @dev:        device the extcon belongs to
1036  * @edev:       the extcon device to unregister
1037  *
1038  * Unregister extcon device that is registered with devm_extcon_dev_register()
1039  * function.
1040  */
1041 void devm_extcon_dev_unregister(struct device *dev, struct extcon_dev *edev)
1042 {
1043         WARN_ON(devres_release(dev, devm_extcon_dev_unreg,
1044                                devm_extcon_dev_match, edev));
1045 }
1046 EXPORT_SYMBOL_GPL(devm_extcon_dev_unregister);
1047
1048 #ifdef CONFIG_OF
1049 /*
1050  * extcon_get_edev_by_phandle - Get the extcon device from devicetree
1051  * @dev - instance to the given device
1052  * @index - index into list of extcon_dev
1053  *
1054  * return the instance of extcon device
1055  */
1056 struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
1057 {
1058         struct device_node *node;
1059         struct extcon_dev *edev;
1060
1061         if (!dev->of_node) {
1062                 dev_err(dev, "device does not have a device node entry\n");
1063                 return ERR_PTR(-EINVAL);
1064         }
1065
1066         node = of_parse_phandle(dev->of_node, "extcon", index);
1067         if (!node) {
1068                 dev_err(dev, "failed to get phandle in %s node\n",
1069                         dev->of_node->full_name);
1070                 return ERR_PTR(-ENODEV);
1071         }
1072
1073         mutex_lock(&extcon_dev_list_lock);
1074         list_for_each_entry(edev, &extcon_dev_list, entry) {
1075                 if (edev->dev.parent && edev->dev.parent->of_node == node) {
1076                         mutex_unlock(&extcon_dev_list_lock);
1077                         return edev;
1078                 }
1079         }
1080         mutex_unlock(&extcon_dev_list_lock);
1081
1082         return ERR_PTR(-EPROBE_DEFER);
1083 }
1084 #else
1085 struct extcon_dev *extcon_get_edev_by_phandle(struct device *dev, int index)
1086 {
1087         return ERR_PTR(-ENOSYS);
1088 }
1089 #endif /* CONFIG_OF */
1090 EXPORT_SYMBOL_GPL(extcon_get_edev_by_phandle);
1091
1092 /**
1093  * extcon_get_edev_name() - Get the name of the extcon device.
1094  * @edev:       the extcon device
1095  */
1096 const char *extcon_get_edev_name(struct extcon_dev *edev)
1097 {
1098         return !edev ? NULL : edev->name;
1099 }
1100
1101 static int __init extcon_class_init(void)
1102 {
1103         return create_extcon_class();
1104 }
1105 module_init(extcon_class_init);
1106
1107 static void __exit extcon_class_exit(void)
1108 {
1109 #if defined(CONFIG_ANDROID)
1110         class_compat_unregister(switch_class);
1111 #endif
1112         class_destroy(extcon_class);
1113 }
1114 module_exit(extcon_class_exit);
1115
1116 MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
1117 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
1118 MODULE_AUTHOR("Donggeun Kim <dg77.kim@samsung.com>");
1119 MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
1120 MODULE_DESCRIPTION("External connector (extcon) class driver");
1121 MODULE_LICENSE("GPL");