git.oblomov.eu Git - linux-2.6/blob - 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         kfree(cd->devt_attr);
 316         cd->devt_attr = NULL;
 317
 318         if (cd->release)
 319                 cd->release(cd);
 320         else if (cls->release)
 321                 cls->release(cd);
 322         else {
 323                 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
 324                         "it is broken and must be fixed.\n",
 325                         cd->class_id);
 326                 WARN_ON(1);
 327         }
 328 }
 329
 330 static struct kobj_type ktype_class_device = {
 331         .sysfs_ops      = &class_dev_sysfs_ops,
 332         .release        = class_dev_release,
 333 };
 334
 335 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
 336 {
 337         struct kobj_type *ktype = get_ktype(kobj);
 338
 339         if (ktype == &ktype_class_device) {
 340                 struct class_device *class_dev = to_class_dev(kobj);
 341                 if (class_dev->class)
 342                         return 1;
 343         }
 344         return 0;
 345 }
 346
 347 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
 348 {
 349         struct class_device *class_dev = to_class_dev(kobj);
 350
 351         return class_dev->class->name;
 352 }
 353
 354 #ifdef CONFIG_SYSFS_DEPRECATED
 355 char *make_class_name(const char *name, struct kobject *kobj)
 356 {
 357         char *class_name;
 358         int size;
 359
 360         size = strlen(name) + strlen(kobject_name(kobj)) + 2;
 361
 362         class_name = kmalloc(size, GFP_KERNEL);
 363         if (!class_name)
 364                 return NULL;
 365
 366         strcpy(class_name, name);
 367         strcat(class_name, ":");
 368         strcat(class_name, kobject_name(kobj));
 369         return class_name;
 370 }
 371
 372 static int deprecated_class_uevent(char **envp, int num_envp, int *cur_index,
 373                                    char *buffer, int buffer_size,
 374                                    int *cur_len,
 375                                    struct class_device *class_dev)
 376 {
 377         struct device *dev = class_dev->dev;
 378         char *path;
 379
 380         if (!dev)
 381                 return 0;
 382
 383         /* add device, backing this class device (deprecated) */
 384         path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 385
 386         add_uevent_var(envp, num_envp, cur_index, buffer, buffer_size,
 387                        cur_len, "PHYSDEVPATH=%s", path);
 388         kfree(path);
 389
 390         if (dev->bus)
 391                 add_uevent_var(envp, num_envp, cur_index,
 392                                buffer, buffer_size, cur_len,
 393                                "PHYSDEVBUS=%s", dev->bus->name);
 394
 395         if (dev->driver)
 396                 add_uevent_var(envp, num_envp, cur_index,
 397                                buffer, buffer_size, cur_len,
 398                                "PHYSDEVDRIVER=%s", dev->driver->name);
 399         return 0;
 400 }
 401
 402 static int make_deprecated_class_device_links(struct class_device *class_dev)
 403 {
 404         char *class_name;
 405         int error;
 406
 407         if (!class_dev->dev)
 408                 return 0;
 409
 410         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 411         if (class_name)
 412                 error = sysfs_create_link(&class_dev->dev->kobj,
 413                                           &class_dev->kobj, class_name);
 414         else
 415                 error = -ENOMEM;
 416         kfree(class_name);
 417         return error;
 418 }
 419
 420 static void remove_deprecated_class_device_links(struct class_device *class_dev)
 421 {
 422         char *class_name;
 423
 424         if (!class_dev->dev)
 425                 return;
 426
 427         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 428         if (class_name)
 429                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
 430         kfree(class_name);
 431 }
 432 #else
 433 static inline int deprecated_class_uevent(char **envp, int num_envp,
 434                                           int *cur_index, char *buffer,
 435                                           int buffer_size, int *cur_len,
 436                                           struct class_device *class_dev)
 437 { return 0; }
 438 static inline int make_deprecated_class_device_links(struct class_device *cd)
 439 { return 0; }
 440 static void remove_deprecated_class_device_links(struct class_device *cd)
 441 { }
 442 #endif
 443
 444 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
 445                          int num_envp, char *buffer, int buffer_size)
 446 {
 447         struct class_device *class_dev = to_class_dev(kobj);
 448         int i = 0;
 449         int length = 0;
 450         int retval = 0;
 451
 452         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 453
 454         deprecated_class_uevent(envp, num_envp, &i, buffer, buffer_size,
 455                                 &length, class_dev);
 456
 457         if (MAJOR(class_dev->devt)) {
 458                 add_uevent_var(envp, num_envp, &i,
 459                                buffer, buffer_size, &length,
 460                                "MAJOR=%u", MAJOR(class_dev->devt));
 461
 462                 add_uevent_var(envp, num_envp, &i,
 463                                buffer, buffer_size, &length,
 464                                "MINOR=%u", MINOR(class_dev->devt));
 465         }
 466
 467         /* terminate, set to next free slot, shrink available space */
 468         envp[i] = NULL;
 469         envp = &envp[i];
 470         num_envp -= i;
 471         buffer = &buffer[length];
 472         buffer_size -= length;
 473
 474         if (class_dev->uevent) {
 475                 /* have the class device specific function add its stuff */
 476                 retval = class_dev->uevent(class_dev, envp, num_envp,
 477                                             buffer, buffer_size);
 478                 if (retval)
 479                         pr_debug("class_dev->uevent() returned %d\n", retval);
 480         } else if (class_dev->class->uevent) {
 481                 /* have the class specific function add its stuff */
 482                 retval = class_dev->class->uevent(class_dev, envp, num_envp,
 483                                                    buffer, buffer_size);
 484                 if (retval)
 485                         pr_debug("class->uevent() returned %d\n", retval);
 486         }
 487
 488         return retval;
 489 }
 490
 491 static struct kset_uevent_ops class_uevent_ops = {
 492         .filter =       class_uevent_filter,
 493         .name =         class_uevent_name,
 494         .uevent =       class_uevent,
 495 };
 496
 497 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
 498
 499
 500 static int class_device_add_attrs(struct class_device * cd)
 501 {
 502         int i;
 503         int error = 0;
 504         struct class * cls = cd->class;
 505
 506         if (cls->class_dev_attrs) {
 507                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 508                         error = class_device_create_file(cd,
 509                                                          &cls->class_dev_attrs[i]);
 510                         if (error)
 511                                 goto Err;
 512                 }
 513         }
 514  Done:
 515         return error;
 516  Err:
 517         while (--i >= 0)
 518                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 519         goto Done;
 520 }
 521
 522 static void class_device_remove_attrs(struct class_device * cd)
 523 {
 524         int i;
 525         struct class * cls = cd->class;
 526
 527         if (cls->class_dev_attrs) {
 528                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 529                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 530         }
 531 }
 532
 533 static int class_device_add_groups(struct class_device * cd)
 534 {
 535         int i;
 536         int error = 0;
 537
 538         if (cd->groups) {
 539                 for (i = 0; cd->groups[i]; i++) {
 540                         error = sysfs_create_group(&cd->kobj, cd->groups[i]);
 541                         if (error) {
 542                                 while (--i >= 0)
 543                                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 544                                 goto out;
 545                         }
 546                 }
 547         }
 548 out:
 549         return error;
 550 }
 551
 552 static void class_device_remove_groups(struct class_device * cd)
 553 {
 554         int i;
 555         if (cd->groups) {
 556                 for (i = 0; cd->groups[i]; i++) {
 557                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 558                 }
 559         }
 560 }
 561
 562 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 563 {
 564         return print_dev_t(buf, class_dev->devt);
 565 }
 566
 567 static ssize_t store_uevent(struct class_device *class_dev,
 568                             const char *buf, size_t count)
 569 {
 570         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 571         return count;
 572 }
 573
 574 void class_device_initialize(struct class_device *class_dev)
 575 {
 576         kobj_set_kset_s(class_dev, class_obj_subsys);
 577         kobject_init(&class_dev->kobj);
 578         INIT_LIST_HEAD(&class_dev->node);
 579 }
 580
 581 int class_device_add(struct class_device *class_dev)
 582 {
 583         struct class *parent_class = NULL;
 584         struct class_device *parent_class_dev = NULL;
 585         struct class_interface *class_intf;
 586         int error = -EINVAL;
 587
 588         class_dev = class_device_get(class_dev);
 589         if (!class_dev)
 590                 return -EINVAL;
 591
 592         if (!strlen(class_dev->class_id))
 593                 goto out1;
 594
 595         parent_class = class_get(class_dev->class);
 596         if (!parent_class)
 597                 goto out1;
 598
 599         parent_class_dev = class_device_get(class_dev->parent);
 600
 601         pr_debug("CLASS: registering class device: ID = '%s'\n",
 602                  class_dev->class_id);
 603
 604         /* first, register with generic layer. */
 605         error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 606         if (error)
 607                 goto out2;
 608
 609         if (parent_class_dev)
 610                 class_dev->kobj.parent = &parent_class_dev->kobj;
 611         else
 612                 class_dev->kobj.parent = &parent_class->subsys.kobj;
 613
 614         error = kobject_add(&class_dev->kobj);
 615         if (error)
 616                 goto out2;
 617
 618         /* add the needed attributes to this device */
 619         error = sysfs_create_link(&class_dev->kobj,
 620                                   &parent_class->subsys.kobj, "subsystem");
 621         if (error)
 622                 goto out3;
 623         class_dev->uevent_attr.attr.name = "uevent";
 624         class_dev->uevent_attr.attr.mode = S_IWUSR;
 625         class_dev->uevent_attr.attr.owner = parent_class->owner;
 626         class_dev->uevent_attr.store = store_uevent;
 627         error = class_device_create_file(class_dev, &class_dev->uevent_attr);
 628         if (error)
 629                 goto out3;
 630
 631         if (MAJOR(class_dev->devt)) {
 632                 struct class_device_attribute *attr;
 633                 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 634                 if (!attr) {
 635                         error = -ENOMEM;
 636                         goto out4;
 637                 }
 638                 attr->attr.name = "dev";
 639                 attr->attr.mode = S_IRUGO;
 640                 attr->attr.owner = parent_class->owner;
 641                 attr->show = show_dev;
 642                 error = class_device_create_file(class_dev, attr);
 643                 if (error) {
 644                         kfree(attr);
 645                         goto out4;
 646                 }
 647
 648                 class_dev->devt_attr = attr;
 649         }
 650
 651         error = class_device_add_attrs(class_dev);
 652         if (error)
 653                 goto out5;
 654
 655         if (class_dev->dev) {
 656                 error = sysfs_create_link(&class_dev->kobj,
 657                                           &class_dev->dev->kobj, "device");
 658                 if (error)
 659                         goto out6;
 660         }
 661
 662         error = class_device_add_groups(class_dev);
 663         if (error)
 664                 goto out7;
 665
 666         error = make_deprecated_class_device_links(class_dev);
 667         if (error)
 668                 goto out8;
 669
 670         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 671
 672         /* notify any interfaces this device is now here */
 673         down(&parent_class->sem);
 674         list_add_tail(&class_dev->node, &parent_class->children);
 675         list_for_each_entry(class_intf, &parent_class->interfaces, node) {
 676                 if (class_intf->add)
 677                         class_intf->add(class_dev, class_intf);
 678         }
 679         up(&parent_class->sem);
 680
 681         goto out1;
 682
 683  out8:
 684         class_device_remove_groups(class_dev);
 685  out7:
 686         if (class_dev->dev)
 687                 sysfs_remove_link(&class_dev->kobj, "device");
 688  out6:
 689         class_device_remove_attrs(class_dev);
 690  out5:
 691         if (class_dev->devt_attr)
 692                 class_device_remove_file(class_dev, class_dev->devt_attr);
 693  out4:
 694         class_device_remove_file(class_dev, &class_dev->uevent_attr);
 695  out3:
 696         kobject_del(&class_dev->kobj);
 697  out2:
 698         if(parent_class_dev)
 699                 class_device_put(parent_class_dev);
 700         class_put(parent_class);
 701  out1:
 702         class_device_put(class_dev);
 703         return error;
 704 }
 705
 706 int class_device_register(struct class_device *class_dev)
 707 {
 708         class_device_initialize(class_dev);
 709         return class_device_add(class_dev);
 710 }
 711
 712 /**
 713  * class_device_create - creates a class device and registers it with sysfs
 714  * @cls: pointer to the struct class that this device should be registered to.
 715  * @parent: pointer to the parent struct class_device of this new device, if any.
 716  * @devt: the dev_t for the char device to be added.
 717  * @device: a pointer to a struct device that is assiociated with this class device.
 718  * @fmt: string for the class device's name
 719  *
 720  * This function can be used by char device classes.  A struct
 721  * class_device will be created in sysfs, registered to the specified
 722  * class.
 723  * A "dev" file will be created, showing the dev_t for the device, if
 724  * the dev_t is not 0,0.
 725  * If a pointer to a parent struct class_device is passed in, the newly
 726  * created struct class_device will be a child of that device in sysfs.
 727  * The pointer to the struct class_device will be returned from the
 728  * call.  Any further sysfs files that might be required can be created
 729  * using this pointer.
 730  *
 731  * Note: the struct class passed to this function must have previously
 732  * been created with a call to class_create().
 733  */
 734 struct class_device *class_device_create(struct class *cls,
 735                                          struct class_device *parent,
 736                                          dev_t devt,
 737                                          struct device *device,
 738                                          const char *fmt, ...)
 739 {
 740         va_list args;
 741         struct class_device *class_dev = NULL;
 742         int retval = -ENODEV;
 743
 744         if (cls == NULL || IS_ERR(cls))
 745                 goto error;
 746
 747         class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
 748         if (!class_dev) {
 749                 retval = -ENOMEM;
 750                 goto error;
 751         }
 752
 753         class_dev->devt = devt;
 754         class_dev->dev = device;
 755         class_dev->class = cls;
 756         class_dev->parent = parent;
 757         class_dev->release = class_device_create_release;
 758         class_dev->uevent = class_device_create_uevent;
 759
 760         va_start(args, fmt);
 761         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
 762         va_end(args);
 763         retval = class_device_register(class_dev);
 764         if (retval)
 765                 goto error;
 766
 767         return class_dev;
 768
 769 error:
 770         kfree(class_dev);
 771         return ERR_PTR(retval);
 772 }
 773
 774 void class_device_del(struct class_device *class_dev)
 775 {
 776         struct class *parent_class = class_dev->class;
 777         struct class_device *parent_device = class_dev->parent;
 778         struct class_interface *class_intf;
 779
 780         if (parent_class) {
 781                 down(&parent_class->sem);
 782                 list_del_init(&class_dev->node);
 783                 list_for_each_entry(class_intf, &parent_class->interfaces, node)
 784                         if (class_intf->remove)
 785                                 class_intf->remove(class_dev, class_intf);
 786                 up(&parent_class->sem);
 787         }
 788
 789         if (class_dev->dev) {
 790                 remove_deprecated_class_device_links(class_dev);
 791                 sysfs_remove_link(&class_dev->kobj, "device");
 792         }
 793         sysfs_remove_link(&class_dev->kobj, "subsystem");
 794         class_device_remove_file(class_dev, &class_dev->uevent_attr);
 795         if (class_dev->devt_attr)
 796                 class_device_remove_file(class_dev, class_dev->devt_attr);
 797         class_device_remove_attrs(class_dev);
 798         class_device_remove_groups(class_dev);
 799
 800         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
 801         kobject_del(&class_dev->kobj);
 802
 803         class_device_put(parent_device);
 804         class_put(parent_class);
 805 }
 806
 807 void class_device_unregister(struct class_device *class_dev)
 808 {
 809         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 810                  class_dev->class_id);
 811         class_device_del(class_dev);
 812         class_device_put(class_dev);
 813 }
 814
 815 /**
 816  * class_device_destroy - removes a class device that was created with class_device_create()
 817  * @cls: the pointer to the struct class that this device was registered * with.
 818  * @devt: the dev_t of the device that was previously registered.
 819  *
 820  * This call unregisters and cleans up a class device that was created with a
 821  * call to class_device_create()
 822  */
 823 void class_device_destroy(struct class *cls, dev_t devt)
 824 {
 825         struct class_device *class_dev = NULL;
 826         struct class_device *class_dev_tmp;
 827
 828         down(&cls->sem);
 829         list_for_each_entry(class_dev_tmp, &cls->children, node) {
 830                 if (class_dev_tmp->devt == devt) {
 831                         class_dev = class_dev_tmp;
 832                         break;
 833                 }
 834         }
 835         up(&cls->sem);
 836
 837         if (class_dev)
 838                 class_device_unregister(class_dev);
 839 }
 840
 841 struct class_device * class_device_get(struct class_device *class_dev)
 842 {
 843         if (class_dev)
 844                 return to_class_dev(kobject_get(&class_dev->kobj));
 845         return NULL;
 846 }
 847
 848 void class_device_put(struct class_device *class_dev)
 849 {
 850         if (class_dev)
 851                 kobject_put(&class_dev->kobj);
 852 }
 853
 854
 855 int class_interface_register(struct class_interface *class_intf)
 856 {
 857         struct class *parent;
 858         struct class_device *class_dev;
 859         struct device *dev;
 860
 861         if (!class_intf || !class_intf->class)
 862                 return -ENODEV;
 863
 864         parent = class_get(class_intf->class);
 865         if (!parent)
 866                 return -EINVAL;
 867
 868         down(&parent->sem);
 869         list_add_tail(&class_intf->node, &parent->interfaces);
 870         if (class_intf->add) {
 871                 list_for_each_entry(class_dev, &parent->children, node)
 872                         class_intf->add(class_dev, class_intf);
 873         }
 874         if (class_intf->add_dev) {
 875                 list_for_each_entry(dev, &parent->devices, node)
 876                         class_intf->add_dev(dev, class_intf);
 877         }
 878         up(&parent->sem);
 879
 880         return 0;
 881 }
 882
 883 void class_interface_unregister(struct class_interface *class_intf)
 884 {
 885         struct class * parent = class_intf->class;
 886         struct class_device *class_dev;
 887         struct device *dev;
 888
 889         if (!parent)
 890                 return;
 891
 892         down(&parent->sem);
 893         list_del_init(&class_intf->node);
 894         if (class_intf->remove) {
 895                 list_for_each_entry(class_dev, &parent->children, node)
 896                         class_intf->remove(class_dev, class_intf);
 897         }
 898         if (class_intf->remove_dev) {
 899                 list_for_each_entry(dev, &parent->devices, node)
 900                         class_intf->remove_dev(dev, class_intf);
 901         }
 902         up(&parent->sem);
 903
 904         class_put(parent);
 905 }
 906
 907 int __init classes_init(void)
 908 {
 909         int retval;
 910
 911         retval = subsystem_register(&class_subsys);
 912         if (retval)
 913                 return retval;
 914
 915         /* ick, this is ugly, the things we go through to keep from showing up
 916          * in sysfs... */
 917         subsystem_init(&class_obj_subsys);
 918         if (!class_obj_subsys.kobj.parent)
 919                 class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
 920         return 0;
 921 }
 922
 923 EXPORT_SYMBOL_GPL(class_create_file);
 924 EXPORT_SYMBOL_GPL(class_remove_file);
 925 EXPORT_SYMBOL_GPL(class_register);
 926 EXPORT_SYMBOL_GPL(class_unregister);
 927 EXPORT_SYMBOL_GPL(class_create);
 928 EXPORT_SYMBOL_GPL(class_destroy);
 929
 930 EXPORT_SYMBOL_GPL(class_device_register);
 931 EXPORT_SYMBOL_GPL(class_device_unregister);
 932 EXPORT_SYMBOL_GPL(class_device_initialize);
 933 EXPORT_SYMBOL_GPL(class_device_add);
 934 EXPORT_SYMBOL_GPL(class_device_del);
 935 EXPORT_SYMBOL_GPL(class_device_get);
 936 EXPORT_SYMBOL_GPL(class_device_put);
 937 EXPORT_SYMBOL_GPL(class_device_create);
 938 EXPORT_SYMBOL_GPL(class_device_destroy);
 939 EXPORT_SYMBOL_GPL(class_device_create_file);
 940 EXPORT_SYMBOL_GPL(class_device_remove_file);
 941 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
 942 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
 943
 944 EXPORT_SYMBOL_GPL(class_interface_register);
 945 EXPORT_SYMBOL_GPL(class_interface_unregister);