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