drivers/base/class.c

   1 /*
   2  * class.c - basic device class management
   3  *
   4  * Copyright (c) 2002-3 Patrick Mochel
   5  * Copyright (c) 2002-3 Open Source Development Labs
   6  * Copyright (c) 2003-2004 Greg Kroah-Hartman
   7  * Copyright (c) 2003-2004 IBM Corp.
   8  *
   9  * This file is released under the GPLv2
  10  *
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/string.h>
  17 #include <linux/kdev_t.h>
  18 #include <linux/err.h>
  19 #include <linux/slab.h>
  20 #include "base.h"
  21
  22 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
  23 #define to_class(obj) container_of(obj, struct class, subsys.kobj)
  24
  25 static ssize_t
  26 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
  27 {
  28         struct class_attribute * class_attr = to_class_attr(attr);
  29         struct class * dc = to_class(kobj);
  30         ssize_t ret = -EIO;
  31
  32         if (class_attr->show)
  33                 ret = class_attr->show(dc, buf);
  34         return ret;
  35 }
  36
  37 static ssize_t
  38 class_attr_store(struct kobject * kobj, struct attribute * attr,
  39                  const char * buf, size_t count)
  40 {
  41         struct class_attribute * class_attr = to_class_attr(attr);
  42         struct class * dc = to_class(kobj);
  43         ssize_t ret = -EIO;
  44
  45         if (class_attr->store)
  46                 ret = class_attr->store(dc, buf, count);
  47         return ret;
  48 }
  49
  50 static void class_release(struct kobject * kobj)
  51 {
  52         struct class *class = to_class(kobj);
  53
  54         pr_debug("class '%s': release.\n", class->name);
  55
  56         if (class->class_release)
  57                 class->class_release(class);
  58         else
  59                 pr_debug("class '%s' does not have a release() function, "
  60                          "be careful\n", class->name);
  61 }
  62
  63 static struct sysfs_ops class_sysfs_ops = {
  64         .show   = class_attr_show,
  65         .store  = class_attr_store,
  66 };
  67
  68 static struct kobj_type ktype_class = {
  69         .sysfs_ops      = &class_sysfs_ops,
  70         .release        = class_release,
  71 };
  72
  73 /* Hotplug events for classes go to the class_obj subsys */
  74 static decl_subsys(class, &ktype_class, NULL);
  75
  76
  77 int class_create_file(struct class * cls, const struct class_attribute * attr)
  78 {
  79         int error;
  80         if (cls) {
  81                 error = sysfs_create_file(&cls->subsys.kobj, &attr->attr);
  82         } else
  83                 error = -EINVAL;
  84         return error;
  85 }
  86
  87 void class_remove_file(struct class * cls, const struct class_attribute * attr)
  88 {
  89         if (cls)
  90                 sysfs_remove_file(&cls->subsys.kobj, &attr->attr);
  91 }
  92
  93 static struct class *class_get(struct class *cls)
  94 {
  95         if (cls)
  96                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
  97         return NULL;
  98 }
  99
 100 static void class_put(struct class * cls)
 101 {
 102         if (cls)
 103                 subsys_put(&cls->subsys);
 104 }
 105
 106
 107 static int add_class_attrs(struct class * cls)
 108 {
 109         int i;
 110         int error = 0;
 111
 112         if (cls->class_attrs) {
 113                 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
 114                         error = class_create_file(cls,&cls->class_attrs[i]);
 115                         if (error)
 116                                 goto Err;
 117                 }
 118         }
 119  Done:
 120         return error;
 121  Err:
 122         while (--i >= 0)
 123                 class_remove_file(cls,&cls->class_attrs[i]);
 124         goto Done;
 125 }
 126
 127 static void remove_class_attrs(struct class * cls)
 128 {
 129         int i;
 130
 131         if (cls->class_attrs) {
 132                 for (i = 0; attr_name(cls->class_attrs[i]); i++)
 133                         class_remove_file(cls,&cls->class_attrs[i]);
 134         }
 135 }
 136
 137 int class_register(struct class * cls)
 138 {
 139         int error;
 140
 141         pr_debug("device class '%s': registering\n", cls->name);
 142
 143         INIT_LIST_HEAD(&cls->children);
 144         INIT_LIST_HEAD(&cls->devices);
 145         INIT_LIST_HEAD(&cls->interfaces);
 146         kset_init(&cls->class_dirs);
 147         init_MUTEX(&cls->sem);
 148         error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);
 149         if (error)
 150                 return error;
 151
 152         subsys_set_kset(cls, class_subsys);
 153
 154         error = subsystem_register(&cls->subsys);
 155         if (!error) {
 156                 error = add_class_attrs(class_get(cls));
 157                 class_put(cls);
 158         }
 159         return error;
 160 }
 161
 162 void class_unregister(struct class * cls)
 163 {
 164         pr_debug("device class '%s': unregistering\n", cls->name);
 165         remove_class_attrs(cls);
 166         subsystem_unregister(&cls->subsys);
 167 }
 168
 169 static void class_create_release(struct class *cls)
 170 {
 171         pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
 172         kfree(cls);
 173 }
 174
 175 static void class_device_create_release(struct class_device *class_dev)
 176 {
 177         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
 178         kfree(class_dev);
 179 }
 180
 181 /* needed to allow these devices to have parent class devices */
 182 static int class_device_create_uevent(struct class_device *class_dev,
 183                                        char **envp, int num_envp,
 184                                        char *buffer, int buffer_size)
 185 {
 186         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
 187         return 0;
 188 }
 189
 190 /**
 191  * class_create - create a struct class structure
 192  * @owner: pointer to the module that is to "own" this struct class
 193  * @name: pointer to a string for the name of this class.
 194  *
 195  * This is used to create a struct class pointer that can then be used
 196  * in calls to class_device_create().
 197  *
 198  * Note, the pointer created here is to be destroyed when finished by
 199  * making a call to class_destroy().
 200  */
 201 struct class *class_create(struct module *owner, const char *name)
 202 {
 203         struct class *cls;
 204         int retval;
 205
 206         cls = kzalloc(sizeof(*cls), GFP_KERNEL);
 207         if (!cls) {
 208                 retval = -ENOMEM;
 209                 goto error;
 210         }
 211
 212         cls->name = name;
 213         cls->owner = owner;
 214         cls->class_release = class_create_release;
 215         cls->release = class_device_create_release;
 216
 217         retval = class_register(cls);
 218         if (retval)
 219                 goto error;
 220
 221         return cls;
 222
 223 error:
 224         kfree(cls);
 225         return ERR_PTR(retval);
 226 }
 227
 228 /**
 229  * class_destroy - destroys a struct class structure
 230  * @cls: pointer to the struct class that is to be destroyed
 231  *
 232  * Note, the pointer to be destroyed must have been created with a call
 233  * to class_create().
 234  */
 235 void class_destroy(struct class *cls)
 236 {
 237         if ((cls == NULL) || (IS_ERR(cls)))
 238                 return;
 239
 240         class_unregister(cls);
 241 }
 242
 243 /* Class Device Stuff */
 244
 245 int class_device_create_file(struct class_device * class_dev,
 246                              const struct class_device_attribute * attr)
 247 {
 248         int error = -EINVAL;
 249         if (class_dev)
 250                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 251         return error;
 252 }
 253
 254 void class_device_remove_file(struct class_device * class_dev,
 255                               const struct class_device_attribute * attr)
 256 {
 257         if (class_dev)
 258                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 259 }
 260
 261 int class_device_create_bin_file(struct class_device *class_dev,
 262                                  struct bin_attribute *attr)
 263 {
 264         int error = -EINVAL;
 265         if (class_dev)
 266                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
 267         return error;
 268 }
 269
 270 void class_device_remove_bin_file(struct class_device *class_dev,
 271                                   struct bin_attribute *attr)
 272 {
 273         if (class_dev)
 274                 sysfs_remove_bin_file(&class_dev->kobj, attr);
 275 }
 276
 277 static ssize_t
 278 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 279                        char * buf)
 280 {
 281         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 282         struct class_device * cd = to_class_dev(kobj);
 283         ssize_t ret = 0;
 284
 285         if (class_dev_attr->show)
 286                 ret = class_dev_attr->show(cd, buf);
 287         return ret;
 288 }
 289
 290 static ssize_t
 291 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 292                         const char * buf, size_t count)
 293 {
 294         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 295         struct class_device * cd = to_class_dev(kobj);
 296         ssize_t ret = 0;
 297
 298         if (class_dev_attr->store)
 299                 ret = class_dev_attr->store(cd, buf, count);
 300         return ret;
 301 }
 302
 303 static struct sysfs_ops class_dev_sysfs_ops = {
 304         .show   = class_device_attr_show,
 305         .store  = class_device_attr_store,
 306 };
 307
 308 static void class_dev_release(struct kobject * kobj)
 309 {
 310         struct class_device *cd = to_class_dev(kobj);
 311         struct class * cls = cd->class;
 312
 313         pr_debug("device class '%s': release.\n", cd->class_id);
 314
 315         if (cd->release)
 316                 cd->release(cd);
 317         else if (cls->release)
 318                 cls->release(cd);
 319         else {
 320                 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
 321                         "it is broken and must be fixed.\n",
 322                         cd->class_id);
 323                 WARN_ON(1);
 324         }
 325 }
 326
 327 static struct kobj_type ktype_class_device = {
 328         .sysfs_ops      = &class_dev_sysfs_ops,
 329         .release        = class_dev_release,
 330 };
 331
 332 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
 333 {
 334         struct kobj_type *ktype = get_ktype(kobj);
 335
 336         if (ktype == &ktype_class_device) {
 337                 struct class_device *class_dev = to_class_dev(kobj);
 338                 if (class_dev->class)
 339                         return 1;
 340         }
 341         return 0;
 342 }
 343
 344 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
 345 {
 346         struct class_device *class_dev = to_class_dev(kobj);
 347
 348         return class_dev->class->name;
 349 }
 350
 351 #ifdef CONFIG_SYSFS_DEPRECATED
 352 char *make_class_name(const char *name, struct kobject *kobj)
 353 {
 354         char *class_name;
 355         int size;
 356
 357         size = strlen(name) + strlen(kobject_name(kobj)) + 2;
 358
 359         class_name = kmalloc(size, GFP_KERNEL);
 360         if (!class_name)
 361                 return NULL;
 362
 363         strcpy(class_name, name);
 364         strcat(class_name, ":");
 365         strcat(class_name, kobject_name(kobj));
 366         return class_name;
 367 }
 368
 369 static int make_deprecated_class_device_links(struct class_device *class_dev)
 370 {
 371         char *class_name;
 372         int error;
 373
 374         if (!class_dev->dev)
 375                 return 0;
 376
 377         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 378         if (class_name)
 379                 error = sysfs_create_link(&class_dev->dev->kobj,
 380                                           &class_dev->kobj, class_name);
 381         else
 382                 error = -ENOMEM;
 383         kfree(class_name);
 384         return error;
 385 }
 386
 387 static void remove_deprecated_class_device_links(struct class_device *class_dev)
 388 {
 389         char *class_name;
 390
 391         if (!class_dev->dev)
 392                 return;
 393
 394         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 395         if (class_name)
 396                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
 397         kfree(class_name);
 398 }
 399 #else
 400 static inline int make_deprecated_class_device_links(struct class_device *cd)
 401 { return 0; }
 402 static void remove_deprecated_class_device_links(struct class_device *cd)
 403 { }
 404 #endif
 405
 406 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
 407                          int num_envp, char *buffer, int buffer_size)
 408 {
 409         struct class_device *class_dev = to_class_dev(kobj);
 410         struct device *dev = class_dev->dev;
 411         int i = 0;
 412         int length = 0;
 413         int retval = 0;
 414
 415         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 416
 417         if (MAJOR(class_dev->devt)) {
 418                 add_uevent_var(envp, num_envp, &i,
 419                                buffer, buffer_size, &length,
 420                                "MAJOR=%u", MAJOR(class_dev->devt));
 421
 422                 add_uevent_var(envp, num_envp, &i,
 423                                buffer, buffer_size, &length,
 424                                "MINOR=%u", MINOR(class_dev->devt));
 425         }
 426
 427         if (dev) {
 428                 const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 429                 if (path) {
 430                         add_uevent_var(envp, num_envp, &i,
 431                                        buffer, buffer_size, &length,
 432                                        "PHYSDEVPATH=%s", path);
 433                         kfree(path);
 434                 }
 435
 436                 if (dev->bus)
 437                         add_uevent_var(envp, num_envp, &i,
 438                                        buffer, buffer_size, &length,
 439                                        "PHYSDEVBUS=%s", dev->bus->name);
 440
 441                 if (dev->driver)
 442                         add_uevent_var(envp, num_envp, &i,
 443                                        buffer, buffer_size, &length,
 444                                        "PHYSDEVDRIVER=%s", dev->driver->name);
 445         }
 446
 447         /* terminate, set to next free slot, shrink available space */
 448         envp[i] = NULL;
 449         envp = &envp[i];
 450         num_envp -= i;
 451         buffer = &buffer[length];
 452         buffer_size -= length;
 453
 454         if (class_dev->uevent) {
 455                 /* have the class device specific function add its stuff */
 456                 retval = class_dev->uevent(class_dev, envp, num_envp,
 457                                             buffer, buffer_size);
 458                 if (retval)
 459                         pr_debug("class_dev->uevent() returned %d\n", retval);
 460         } else if (class_dev->class->uevent) {
 461                 /* have the class specific function add its stuff */
 462                 retval = class_dev->class->uevent(class_dev, envp, num_envp,
 463                                                    buffer, buffer_size);
 464                 if (retval)
 465                         pr_debug("class->uevent() returned %d\n", retval);
 466         }
 467
 468         return retval;
 469 }
 470
 471 static struct kset_uevent_ops class_uevent_ops = {
 472         .filter =       class_uevent_filter,
 473         .name =         class_uevent_name,
 474         .uevent =       class_uevent,
 475 };
 476
 477 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
 478
 479
 480 static int class_device_add_attrs(struct class_device * cd)
 481 {
 482         int i;
 483         int error = 0;
 484         struct class * cls = cd->class;
 485
 486         if (cls->class_dev_attrs) {
 487                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 488                         error = class_device_create_file(cd,
 489                                                          &cls->class_dev_attrs[i]);
 490                         if (error)
 491                                 goto Err;
 492                 }
 493         }
 494  Done:
 495         return error;
 496  Err:
 497         while (--i >= 0)
 498                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 499         goto Done;
 500 }
 501
 502 static void class_device_remove_attrs(struct class_device * cd)
 503 {
 504         int i;
 505         struct class * cls = cd->class;
 506
 507         if (cls->class_dev_attrs) {
 508                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 509                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 510         }
 511 }
 512
 513 static int class_device_add_groups(struct class_device * cd)
 514 {
 515         int i;
 516         int error = 0;
 517
 518         if (cd->groups) {
 519                 for (i = 0; cd->groups[i]; i++) {
 520                         error = sysfs_create_group(&cd->kobj, cd->groups[i]);
 521                         if (error) {
 522                                 while (--i >= 0)
 523                                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 524                                 goto out;
 525                         }
 526                 }
 527         }
 528 out:
 529         return error;
 530 }
 531
 532 static void class_device_remove_groups(struct class_device * cd)
 533 {
 534         int i;
 535         if (cd->groups) {
 536                 for (i = 0; cd->groups[i]; i++) {
 537                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 538                 }
 539         }
 540 }
 541
 542 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 543 {
 544         return print_dev_t(buf, class_dev->devt);
 545 }
 546
 547 static struct class_device_attribute class_devt_attr =
 548         __ATTR(dev, S_IRUGO, show_dev, NULL);
 549
 550 static ssize_t store_uevent(struct class_device *class_dev,
 551                             const char *buf, size_t count)
 552 {
 553         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 554         return count;
 555 }
 556
 557 static struct class_device_attribute class_uevent_attr =
 558         __ATTR(uevent, S_IWUSR, NULL, store_uevent);
 559
 560 void class_device_initialize(struct class_device *class_dev)
 561 {
 562         kobj_set_kset_s(class_dev, class_obj_subsys);
 563         kobject_init(&class_dev->kobj);
 564         INIT_LIST_HEAD(&class_dev->node);
 565 }
 566
 567 int class_device_add(struct class_device *class_dev)
 568 {
 569         struct class *parent_class = NULL;
 570         struct class_device *parent_class_dev = NULL;
 571         struct class_interface *class_intf;
 572         int error = -EINVAL;
 573
 574         class_dev = class_device_get(class_dev);
 575         if (!class_dev)
 576                 return -EINVAL;
 577
 578         if (!strlen(class_dev->class_id))
 579                 goto out1;
 580
 581         parent_class = class_get(class_dev->class);
 582         if (!parent_class)
 583                 goto out1;
 584
 585         parent_class_dev = class_device_get(class_dev->parent);
 586
 587         pr_debug("CLASS: registering class device: ID = '%s'\n",
 588                  class_dev->class_id);
 589
 590         /* first, register with generic layer. */
 591         error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 592         if (error)
 593                 goto out2;
 594
 595         if (parent_class_dev)
 596                 class_dev->kobj.parent = &parent_class_dev->kobj;
 597         else
 598                 class_dev->kobj.parent = &parent_class->subsys.kobj;
 599
 600         error = kobject_add(&class_dev->kobj);
 601         if (error)
 602                 goto out2;
 603
 604         /* add the needed attributes to this device */
 605         error = sysfs_create_link(&class_dev->kobj,
 606                                   &parent_class->subsys.kobj, "subsystem");
 607         if (error)
 608                 goto out3;
 609
 610         error = class_device_create_file(class_dev, &class_uevent_attr);
 611         if (error)
 612                 goto out3;
 613
 614         if (MAJOR(class_dev->devt)) {
 615                 error = class_device_create_file(class_dev, &class_devt_attr);
 616                 if (error)
 617                         goto out4;
 618         }
 619
 620         error = class_device_add_attrs(class_dev);
 621         if (error)
 622                 goto out5;
 623
 624         if (class_dev->dev) {
 625                 error = sysfs_create_link(&class_dev->kobj,
 626                                           &class_dev->dev->kobj, "device");
 627                 if (error)
 628                         goto out6;
 629         }
 630
 631         error = class_device_add_groups(class_dev);
 632         if (error)
 633                 goto out7;
 634
 635         error = make_deprecated_class_device_links(class_dev);
 636         if (error)
 637                 goto out8;
 638
 639         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 640
 641         /* notify any interfaces this device is now here */
 642         down(&parent_class->sem);
 643         list_add_tail(&class_dev->node, &parent_class->children);
 644         list_for_each_entry(class_intf, &parent_class->interfaces, node) {
 645                 if (class_intf->add)
 646                         class_intf->add(class_dev, class_intf);
 647         }
 648         up(&parent_class->sem);
 649
 650         goto out1;
 651
 652  out8:
 653         class_device_remove_groups(class_dev);
 654  out7:
 655         if (class_dev->dev)
 656                 sysfs_remove_link(&class_dev->kobj, "device");
 657  out6:
 658         class_device_remove_attrs(class_dev);
 659  out5:
 660         if (MAJOR(class_dev->devt))
 661                 class_device_remove_file(class_dev, &class_devt_attr);
 662  out4:
 663         class_device_remove_file(class_dev, &class_uevent_attr);
 664  out3:
 665         kobject_del(&class_dev->kobj);
 666  out2:
 667         if(parent_class_dev)
 668                 class_device_put(parent_class_dev);
 669         class_put(parent_class);
 670  out1:
 671         class_device_put(class_dev);
 672         return error;
 673 }
 674
 675 int class_device_register(struct class_device *class_dev)
 676 {
 677         class_device_initialize(class_dev);
 678         return class_device_add(class_dev);
 679 }
 680
 681 /**
 682  * class_device_create - creates a class device and registers it with sysfs
 683  * @cls: pointer to the struct class that this device should be registered to.
 684  * @parent: pointer to the parent struct class_device of this new device, if any.
 685  * @devt: the dev_t for the char device to be added.
 686  * @device: a pointer to a struct device that is assiociated with this class device.
 687  * @fmt: string for the class device's name
 688  *
 689  * This function can be used by char device classes.  A struct
 690  * class_device will be created in sysfs, registered to the specified
 691  * class.
 692  * A "dev" file will be created, showing the dev_t for the device, if
 693  * the dev_t is not 0,0.
 694  * If a pointer to a parent struct class_device is passed in, the newly
 695  * created struct class_device will be a child of that device in sysfs.
 696  * The pointer to the struct class_device will be returned from the
 697  * call.  Any further sysfs files that might be required can be created
 698  * using this pointer.
 699  *
 700  * Note: the struct class passed to this function must have previously
 701  * been created with a call to class_create().
 702  */
 703 struct class_device *class_device_create(struct class *cls,
 704                                          struct class_device *parent,
 705                                          dev_t devt,
 706                                          struct device *device,
 707                                          const char *fmt, ...)
 708 {
 709         va_list args;
 710         struct class_device *class_dev = NULL;
 711         int retval = -ENODEV;
 712
 713         if (cls == NULL || IS_ERR(cls))
 714                 goto error;
 715
 716         class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
 717         if (!class_dev) {
 718                 retval = -ENOMEM;
 719                 goto error;
 720         }
 721
 722         class_dev->devt = devt;
 723         class_dev->dev = device;
 724         class_dev->class = cls;
 725         class_dev->parent = parent;
 726         class_dev->release = class_device_create_release;
 727         class_dev->uevent = class_device_create_uevent;
 728
 729         va_start(args, fmt);
 730         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
 731         va_end(args);
 732         retval = class_device_register(class_dev);
 733         if (retval)
 734                 goto error;
 735
 736         return class_dev;
 737
 738 error:
 739         kfree(class_dev);
 740         return ERR_PTR(retval);
 741 }
 742
 743 void class_device_del(struct class_device *class_dev)
 744 {
 745         struct class *parent_class = class_dev->class;
 746         struct class_device *parent_device = class_dev->parent;
 747         struct class_interface *class_intf;
 748
 749         if (parent_class) {
 750                 down(&parent_class->sem);
 751                 list_del_init(&class_dev->node);
 752                 list_for_each_entry(class_intf, &parent_class->interfaces, node)
 753                         if (class_intf->remove)
 754                                 class_intf->remove(class_dev, class_intf);
 755                 up(&parent_class->sem);
 756         }
 757
 758         if (class_dev->dev) {
 759                 remove_deprecated_class_device_links(class_dev);
 760                 sysfs_remove_link(&class_dev->kobj, "device");
 761         }
 762         sysfs_remove_link(&class_dev->kobj, "subsystem");
 763         class_device_remove_file(class_dev, &class_uevent_attr);
 764         if (MAJOR(class_dev->devt))
 765                 class_device_remove_file(class_dev, &class_devt_attr);
 766         class_device_remove_attrs(class_dev);
 767         class_device_remove_groups(class_dev);
 768
 769         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
 770         kobject_del(&class_dev->kobj);
 771
 772         class_device_put(parent_device);
 773         class_put(parent_class);
 774 }
 775
 776 void class_device_unregister(struct class_device *class_dev)
 777 {
 778         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 779                  class_dev->class_id);
 780         class_device_del(class_dev);
 781         class_device_put(class_dev);
 782 }
 783
 784 /**
 785  * class_device_destroy - removes a class device that was created with class_device_create()
 786  * @cls: the pointer to the struct class that this device was registered * with.
 787  * @devt: the dev_t of the device that was previously registered.
 788  *
 789  * This call unregisters and cleans up a class device that was created with a
 790  * call to class_device_create()
 791  */
 792 void class_device_destroy(struct class *cls, dev_t devt)
 793 {
 794         struct class_device *class_dev = NULL;
 795         struct class_device *class_dev_tmp;
 796
 797         down(&cls->sem);
 798         list_for_each_entry(class_dev_tmp, &cls->children, node) {
 799                 if (class_dev_tmp->devt == devt) {
 800                         class_dev = class_dev_tmp;
 801                         break;
 802                 }
 803         }
 804         up(&cls->sem);
 805
 806         if (class_dev)
 807                 class_device_unregister(class_dev);
 808 }
 809
 810 struct class_device * class_device_get(struct class_device *class_dev)
 811 {
 812         if (class_dev)
 813                 return to_class_dev(kobject_get(&class_dev->kobj));
 814         return NULL;
 815 }
 816
 817 void class_device_put(struct class_device *class_dev)
 818 {
 819         if (class_dev)
 820                 kobject_put(&class_dev->kobj);
 821 }
 822
 823
 824 int class_interface_register(struct class_interface *class_intf)
 825 {
 826         struct class *parent;
 827         struct class_device *class_dev;
 828         struct device *dev;
 829
 830         if (!class_intf || !class_intf->class)
 831                 return -ENODEV;
 832
 833         parent = class_get(class_intf->class);
 834         if (!parent)
 835                 return -EINVAL;
 836
 837         down(&parent->sem);
 838         list_add_tail(&class_intf->node, &parent->interfaces);
 839         if (class_intf->add) {
 840                 list_for_each_entry(class_dev, &parent->children, node)
 841                         class_intf->add(class_dev, class_intf);
 842         }
 843         if (class_intf->add_dev) {
 844                 list_for_each_entry(dev, &parent->devices, node)
 845                         class_intf->add_dev(dev, class_intf);
 846         }
 847         up(&parent->sem);
 848
 849         return 0;
 850 }
 851
 852 void class_interface_unregister(struct class_interface *class_intf)
 853 {
 854         struct class * parent = class_intf->class;
 855         struct class_device *class_dev;
 856         struct device *dev;
 857
 858         if (!parent)
 859                 return;
 860
 861         down(&parent->sem);
 862         list_del_init(&class_intf->node);
 863         if (class_intf->remove) {
 864                 list_for_each_entry(class_dev, &parent->children, node)
 865                         class_intf->remove(class_dev, class_intf);
 866         }
 867         if (class_intf->remove_dev) {
 868                 list_for_each_entry(dev, &parent->devices, node)
 869                         class_intf->remove_dev(dev, class_intf);
 870         }
 871         up(&parent->sem);
 872
 873         class_put(parent);
 874 }
 875
 876 int __init classes_init(void)
 877 {
 878         int retval;
 879
 880         retval = subsystem_register(&class_subsys);
 881         if (retval)
 882                 return retval;
 883
 884         /* ick, this is ugly, the things we go through to keep from showing up
 885          * in sysfs... */
 886         subsystem_init(&class_obj_subsys);
 887         if (!class_obj_subsys.kobj.parent)
 888                 class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
 889         return 0;
 890 }
 891
 892 EXPORT_SYMBOL_GPL(class_create_file);
 893 EXPORT_SYMBOL_GPL(class_remove_file);
 894 EXPORT_SYMBOL_GPL(class_register);
 895 EXPORT_SYMBOL_GPL(class_unregister);
 896 EXPORT_SYMBOL_GPL(class_create);
 897 EXPORT_SYMBOL_GPL(class_destroy);
 898
 899 EXPORT_SYMBOL_GPL(class_device_register);
 900 EXPORT_SYMBOL_GPL(class_device_unregister);
 901 EXPORT_SYMBOL_GPL(class_device_initialize);
 902 EXPORT_SYMBOL_GPL(class_device_add);
 903 EXPORT_SYMBOL_GPL(class_device_del);
 904 EXPORT_SYMBOL_GPL(class_device_get);
 905 EXPORT_SYMBOL_GPL(class_device_put);
 906 EXPORT_SYMBOL_GPL(class_device_create);
 907 EXPORT_SYMBOL_GPL(class_device_destroy);
 908 EXPORT_SYMBOL_GPL(class_device_create_file);
 909 EXPORT_SYMBOL_GPL(class_device_remove_file);
 910 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
 911 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
 912
 913 EXPORT_SYMBOL_GPL(class_interface_register);
 914 EXPORT_SYMBOL_GPL(class_interface_unregister);