err.no 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 class_ktype = {
  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, &class_ktype, 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(kset_get(&cls->subsys), struct class, subsys);
  97         return NULL;
  98 }
  99
 100 static void class_put(struct class * cls)
 101 {
 102         if (cls)
 103                 kset_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         cls->subsys.kobj.kset = &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                                       struct kobj_uevent_env *env)
 184 {
 185         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
 186         return 0;
 187 }
 188
 189 /**
 190  * class_create - create a struct class structure
 191  * @owner: pointer to the module that is to "own" this struct class
 192  * @name: pointer to a string for the name of this class.
 193  *
 194  * This is used to create a struct class pointer that can then be used
 195  * in calls to class_device_create().
 196  *
 197  * Note, the pointer created here is to be destroyed when finished by
 198  * making a call to class_destroy().
 199  */
 200 struct class *class_create(struct module *owner, const char *name)
 201 {
 202         struct class *cls;
 203         int retval;
 204
 205         cls = kzalloc(sizeof(*cls), GFP_KERNEL);
 206         if (!cls) {
 207                 retval = -ENOMEM;
 208                 goto error;
 209         }
 210
 211         cls->name = name;
 212         cls->owner = owner;
 213         cls->class_release = class_create_release;
 214         cls->release = class_device_create_release;
 215
 216         retval = class_register(cls);
 217         if (retval)
 218                 goto error;
 219
 220         return cls;
 221
 222 error:
 223         kfree(cls);
 224         return ERR_PTR(retval);
 225 }
 226
 227 /**
 228  * class_destroy - destroys a struct class structure
 229  * @cls: pointer to the struct class that is to be destroyed
 230  *
 231  * Note, the pointer to be destroyed must have been created with a call
 232  * to class_create().
 233  */
 234 void class_destroy(struct class *cls)
 235 {
 236         if ((cls == NULL) || (IS_ERR(cls)))
 237                 return;
 238
 239         class_unregister(cls);
 240 }
 241
 242 /* Class Device Stuff */
 243
 244 int class_device_create_file(struct class_device * class_dev,
 245                              const struct class_device_attribute * attr)
 246 {
 247         int error = -EINVAL;
 248         if (class_dev)
 249                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 250         return error;
 251 }
 252
 253 void class_device_remove_file(struct class_device * class_dev,
 254                               const struct class_device_attribute * attr)
 255 {
 256         if (class_dev)
 257                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 258 }
 259
 260 static ssize_t
 261 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 262                        char * buf)
 263 {
 264         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 265         struct class_device * cd = to_class_dev(kobj);
 266         ssize_t ret = 0;
 267
 268         if (class_dev_attr->show)
 269                 ret = class_dev_attr->show(cd, buf);
 270         return ret;
 271 }
 272
 273 static ssize_t
 274 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 275                         const char * buf, size_t count)
 276 {
 277         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 278         struct class_device * cd = to_class_dev(kobj);
 279         ssize_t ret = 0;
 280
 281         if (class_dev_attr->store)
 282                 ret = class_dev_attr->store(cd, buf, count);
 283         return ret;
 284 }
 285
 286 static struct sysfs_ops class_dev_sysfs_ops = {
 287         .show   = class_device_attr_show,
 288         .store  = class_device_attr_store,
 289 };
 290
 291 static void class_dev_release(struct kobject * kobj)
 292 {
 293         struct class_device *cd = to_class_dev(kobj);
 294         struct class * cls = cd->class;
 295
 296         pr_debug("device class '%s': release.\n", cd->class_id);
 297
 298         if (cd->release)
 299                 cd->release(cd);
 300         else if (cls->release)
 301                 cls->release(cd);
 302         else {
 303                 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
 304                         "it is broken and must be fixed.\n",
 305                         cd->class_id);
 306                 WARN_ON(1);
 307         }
 308 }
 309
 310 static struct kobj_type class_device_ktype = {
 311         .sysfs_ops      = &class_dev_sysfs_ops,
 312         .release        = class_dev_release,
 313 };
 314
 315 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
 316 {
 317         struct kobj_type *ktype = get_ktype(kobj);
 318
 319         if (ktype == &class_device_ktype) {
 320                 struct class_device *class_dev = to_class_dev(kobj);
 321                 if (class_dev->class)
 322                         return 1;
 323         }
 324         return 0;
 325 }
 326
 327 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
 328 {
 329         struct class_device *class_dev = to_class_dev(kobj);
 330
 331         return class_dev->class->name;
 332 }
 333
 334 #ifdef CONFIG_SYSFS_DEPRECATED
 335 char *make_class_name(const char *name, struct kobject *kobj)
 336 {
 337         char *class_name;
 338         int size;
 339
 340         size = strlen(name) + strlen(kobject_name(kobj)) + 2;
 341
 342         class_name = kmalloc(size, GFP_KERNEL);
 343         if (!class_name)
 344                 return NULL;
 345
 346         strcpy(class_name, name);
 347         strcat(class_name, ":");
 348         strcat(class_name, kobject_name(kobj));
 349         return class_name;
 350 }
 351
 352 static int make_deprecated_class_device_links(struct class_device *class_dev)
 353 {
 354         char *class_name;
 355         int error;
 356
 357         if (!class_dev->dev)
 358                 return 0;
 359
 360         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 361         if (class_name)
 362                 error = sysfs_create_link(&class_dev->dev->kobj,
 363                                           &class_dev->kobj, class_name);
 364         else
 365                 error = -ENOMEM;
 366         kfree(class_name);
 367         return error;
 368 }
 369
 370 static void remove_deprecated_class_device_links(struct class_device *class_dev)
 371 {
 372         char *class_name;
 373
 374         if (!class_dev->dev)
 375                 return;
 376
 377         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 378         if (class_name)
 379                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
 380         kfree(class_name);
 381 }
 382 #else
 383 static inline int make_deprecated_class_device_links(struct class_device *cd)
 384 { return 0; }
 385 static void remove_deprecated_class_device_links(struct class_device *cd)
 386 { }
 387 #endif
 388
 389 static int class_uevent(struct kset *kset, struct kobject *kobj,
 390                         struct kobj_uevent_env *env)
 391 {
 392         struct class_device *class_dev = to_class_dev(kobj);
 393         struct device *dev = class_dev->dev;
 394         int retval = 0;
 395
 396         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 397
 398         if (MAJOR(class_dev->devt)) {
 399                 add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt));
 400
 401                 add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt));
 402         }
 403
 404         if (dev) {
 405                 const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 406                 if (path) {
 407                         add_uevent_var(env, "PHYSDEVPATH=%s", path);
 408                         kfree(path);
 409                 }
 410
 411                 if (dev->bus)
 412                         add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
 413
 414                 if (dev->driver)
 415                         add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
 416         }
 417
 418         if (class_dev->uevent) {
 419                 /* have the class device specific function add its stuff */
 420                 retval = class_dev->uevent(class_dev, env);
 421                 if (retval)
 422                         pr_debug("class_dev->uevent() returned %d\n", retval);
 423         } else if (class_dev->class->uevent) {
 424                 /* have the class specific function add its stuff */
 425                 retval = class_dev->class->uevent(class_dev, env);
 426                 if (retval)
 427                         pr_debug("class->uevent() returned %d\n", retval);
 428         }
 429
 430         return retval;
 431 }
 432
 433 static struct kset_uevent_ops class_uevent_ops = {
 434         .filter =       class_uevent_filter,
 435         .name =         class_uevent_name,
 436         .uevent =       class_uevent,
 437 };
 438
 439 static decl_subsys(class_obj, &class_device_ktype, &class_uevent_ops);
 440
 441
 442 static int class_device_add_attrs(struct class_device * cd)
 443 {
 444         int i;
 445         int error = 0;
 446         struct class * cls = cd->class;
 447
 448         if (cls->class_dev_attrs) {
 449                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 450                         error = class_device_create_file(cd,
 451                                                          &cls->class_dev_attrs[i]);
 452                         if (error)
 453                                 goto Err;
 454                 }
 455         }
 456  Done:
 457         return error;
 458  Err:
 459         while (--i >= 0)
 460                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 461         goto Done;
 462 }
 463
 464 static void class_device_remove_attrs(struct class_device * cd)
 465 {
 466         int i;
 467         struct class * cls = cd->class;
 468
 469         if (cls->class_dev_attrs) {
 470                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 471                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 472         }
 473 }
 474
 475 static int class_device_add_groups(struct class_device * cd)
 476 {
 477         int i;
 478         int error = 0;
 479
 480         if (cd->groups) {
 481                 for (i = 0; cd->groups[i]; i++) {
 482                         error = sysfs_create_group(&cd->kobj, cd->groups[i]);
 483                         if (error) {
 484                                 while (--i >= 0)
 485                                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 486                                 goto out;
 487                         }
 488                 }
 489         }
 490 out:
 491         return error;
 492 }
 493
 494 static void class_device_remove_groups(struct class_device * cd)
 495 {
 496         int i;
 497         if (cd->groups) {
 498                 for (i = 0; cd->groups[i]; i++) {
 499                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 500                 }
 501         }
 502 }
 503
 504 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 505 {
 506         return print_dev_t(buf, class_dev->devt);
 507 }
 508
 509 static struct class_device_attribute class_devt_attr =
 510         __ATTR(dev, S_IRUGO, show_dev, NULL);
 511
 512 static ssize_t store_uevent(struct class_device *class_dev,
 513                             const char *buf, size_t count)
 514 {
 515         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 516         return count;
 517 }
 518
 519 static struct class_device_attribute class_uevent_attr =
 520         __ATTR(uevent, S_IWUSR, NULL, store_uevent);
 521
 522 void class_device_initialize(struct class_device *class_dev)
 523 {
 524         kobj_set_kset_s(class_dev, class_obj_subsys);
 525         kobject_init(&class_dev->kobj);
 526         INIT_LIST_HEAD(&class_dev->node);
 527 }
 528
 529 int class_device_add(struct class_device *class_dev)
 530 {
 531         struct class *parent_class = NULL;
 532         struct class_device *parent_class_dev = NULL;
 533         struct class_interface *class_intf;
 534         int error = -EINVAL;
 535
 536         class_dev = class_device_get(class_dev);
 537         if (!class_dev)
 538                 return -EINVAL;
 539
 540         if (!strlen(class_dev->class_id))
 541                 goto out1;
 542
 543         parent_class = class_get(class_dev->class);
 544         if (!parent_class)
 545                 goto out1;
 546
 547         parent_class_dev = class_device_get(class_dev->parent);
 548
 549         pr_debug("CLASS: registering class device: ID = '%s'\n",
 550                  class_dev->class_id);
 551
 552         /* first, register with generic layer. */
 553         error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 554         if (error)
 555                 goto out2;
 556
 557         if (parent_class_dev)
 558                 class_dev->kobj.parent = &parent_class_dev->kobj;
 559         else
 560                 class_dev->kobj.parent = &parent_class->subsys.kobj;
 561
 562         error = kobject_add(&class_dev->kobj);
 563         if (error)
 564                 goto out2;
 565
 566         /* add the needed attributes to this device */
 567         error = sysfs_create_link(&class_dev->kobj,
 568                                   &parent_class->subsys.kobj, "subsystem");
 569         if (error)
 570                 goto out3;
 571
 572         error = class_device_create_file(class_dev, &class_uevent_attr);
 573         if (error)
 574                 goto out3;
 575
 576         if (MAJOR(class_dev->devt)) {
 577                 error = class_device_create_file(class_dev, &class_devt_attr);
 578                 if (error)
 579                         goto out4;
 580         }
 581
 582         error = class_device_add_attrs(class_dev);
 583         if (error)
 584                 goto out5;
 585
 586         if (class_dev->dev) {
 587                 error = sysfs_create_link(&class_dev->kobj,
 588                                           &class_dev->dev->kobj, "device");
 589                 if (error)
 590                         goto out6;
 591         }
 592
 593         error = class_device_add_groups(class_dev);
 594         if (error)
 595                 goto out7;
 596
 597         error = make_deprecated_class_device_links(class_dev);
 598         if (error)
 599                 goto out8;
 600
 601         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 602
 603         /* notify any interfaces this device is now here */
 604         down(&parent_class->sem);
 605         list_add_tail(&class_dev->node, &parent_class->children);
 606         list_for_each_entry(class_intf, &parent_class->interfaces, node) {
 607                 if (class_intf->add)
 608                         class_intf->add(class_dev, class_intf);
 609         }
 610         up(&parent_class->sem);
 611
 612         goto out1;
 613
 614  out8:
 615         class_device_remove_groups(class_dev);
 616  out7:
 617         if (class_dev->dev)
 618                 sysfs_remove_link(&class_dev->kobj, "device");
 619  out6:
 620         class_device_remove_attrs(class_dev);
 621  out5:
 622         if (MAJOR(class_dev->devt))
 623                 class_device_remove_file(class_dev, &class_devt_attr);
 624  out4:
 625         class_device_remove_file(class_dev, &class_uevent_attr);
 626  out3:
 627         kobject_del(&class_dev->kobj);
 628  out2:
 629         if(parent_class_dev)
 630                 class_device_put(parent_class_dev);
 631         class_put(parent_class);
 632  out1:
 633         class_device_put(class_dev);
 634         return error;
 635 }
 636
 637 int class_device_register(struct class_device *class_dev)
 638 {
 639         class_device_initialize(class_dev);
 640         return class_device_add(class_dev);
 641 }
 642
 643 /**
 644  * class_device_create - creates a class device and registers it with sysfs
 645  * @cls: pointer to the struct class that this device should be registered to.
 646  * @parent: pointer to the parent struct class_device of this new device, if any.
 647  * @devt: the dev_t for the char device to be added.
 648  * @device: a pointer to a struct device that is assiociated with this class device.
 649  * @fmt: string for the class device's name
 650  *
 651  * This function can be used by char device classes.  A struct
 652  * class_device will be created in sysfs, registered to the specified
 653  * class.
 654  * A "dev" file will be created, showing the dev_t for the device, if
 655  * the dev_t is not 0,0.
 656  * If a pointer to a parent struct class_device is passed in, the newly
 657  * created struct class_device will be a child of that device in sysfs.
 658  * The pointer to the struct class_device will be returned from the
 659  * call.  Any further sysfs files that might be required can be created
 660  * using this pointer.
 661  *
 662  * Note: the struct class passed to this function must have previously
 663  * been created with a call to class_create().
 664  */
 665 struct class_device *class_device_create(struct class *cls,
 666                                          struct class_device *parent,
 667                                          dev_t devt,
 668                                          struct device *device,
 669                                          const char *fmt, ...)
 670 {
 671         va_list args;
 672         struct class_device *class_dev = NULL;
 673         int retval = -ENODEV;
 674
 675         if (cls == NULL || IS_ERR(cls))
 676                 goto error;
 677
 678         class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
 679         if (!class_dev) {
 680                 retval = -ENOMEM;
 681                 goto error;
 682         }
 683
 684         class_dev->devt = devt;
 685         class_dev->dev = device;
 686         class_dev->class = cls;
 687         class_dev->parent = parent;
 688         class_dev->release = class_device_create_release;
 689         class_dev->uevent = class_device_create_uevent;
 690
 691         va_start(args, fmt);
 692         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
 693         va_end(args);
 694         retval = class_device_register(class_dev);
 695         if (retval)
 696                 goto error;
 697
 698         return class_dev;
 699
 700 error:
 701         kfree(class_dev);
 702         return ERR_PTR(retval);
 703 }
 704
 705 void class_device_del(struct class_device *class_dev)
 706 {
 707         struct class *parent_class = class_dev->class;
 708         struct class_device *parent_device = class_dev->parent;
 709         struct class_interface *class_intf;
 710
 711         if (parent_class) {
 712                 down(&parent_class->sem);
 713                 list_del_init(&class_dev->node);
 714                 list_for_each_entry(class_intf, &parent_class->interfaces, node)
 715                         if (class_intf->remove)
 716                                 class_intf->remove(class_dev, class_intf);
 717                 up(&parent_class->sem);
 718         }
 719
 720         if (class_dev->dev) {
 721                 remove_deprecated_class_device_links(class_dev);
 722                 sysfs_remove_link(&class_dev->kobj, "device");
 723         }
 724         sysfs_remove_link(&class_dev->kobj, "subsystem");
 725         class_device_remove_file(class_dev, &class_uevent_attr);
 726         if (MAJOR(class_dev->devt))
 727                 class_device_remove_file(class_dev, &class_devt_attr);
 728         class_device_remove_attrs(class_dev);
 729         class_device_remove_groups(class_dev);
 730
 731         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
 732         kobject_del(&class_dev->kobj);
 733
 734         class_device_put(parent_device);
 735         class_put(parent_class);
 736 }
 737
 738 void class_device_unregister(struct class_device *class_dev)
 739 {
 740         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 741                  class_dev->class_id);
 742         class_device_del(class_dev);
 743         class_device_put(class_dev);
 744 }
 745
 746 /**
 747  * class_device_destroy - removes a class device that was created with class_device_create()
 748  * @cls: the pointer to the struct class that this device was registered * with.
 749  * @devt: the dev_t of the device that was previously registered.
 750  *
 751  * This call unregisters and cleans up a class device that was created with a
 752  * call to class_device_create()
 753  */
 754 void class_device_destroy(struct class *cls, dev_t devt)
 755 {
 756         struct class_device *class_dev = NULL;
 757         struct class_device *class_dev_tmp;
 758
 759         down(&cls->sem);
 760         list_for_each_entry(class_dev_tmp, &cls->children, node) {
 761                 if (class_dev_tmp->devt == devt) {
 762                         class_dev = class_dev_tmp;
 763                         break;
 764                 }
 765         }
 766         up(&cls->sem);
 767
 768         if (class_dev)
 769                 class_device_unregister(class_dev);
 770 }
 771
 772 struct class_device * class_device_get(struct class_device *class_dev)
 773 {
 774         if (class_dev)
 775                 return to_class_dev(kobject_get(&class_dev->kobj));
 776         return NULL;
 777 }
 778
 779 void class_device_put(struct class_device *class_dev)
 780 {
 781         if (class_dev)
 782                 kobject_put(&class_dev->kobj);
 783 }
 784
 785
 786 int class_interface_register(struct class_interface *class_intf)
 787 {
 788         struct class *parent;
 789         struct class_device *class_dev;
 790         struct device *dev;
 791
 792         if (!class_intf || !class_intf->class)
 793                 return -ENODEV;
 794
 795         parent = class_get(class_intf->class);
 796         if (!parent)
 797                 return -EINVAL;
 798
 799         down(&parent->sem);
 800         list_add_tail(&class_intf->node, &parent->interfaces);
 801         if (class_intf->add) {
 802                 list_for_each_entry(class_dev, &parent->children, node)
 803                         class_intf->add(class_dev, class_intf);
 804         }
 805         if (class_intf->add_dev) {
 806                 list_for_each_entry(dev, &parent->devices, node)
 807                         class_intf->add_dev(dev, class_intf);
 808         }
 809         up(&parent->sem);
 810
 811         return 0;
 812 }
 813
 814 void class_interface_unregister(struct class_interface *class_intf)
 815 {
 816         struct class * parent = class_intf->class;
 817         struct class_device *class_dev;
 818         struct device *dev;
 819
 820         if (!parent)
 821                 return;
 822
 823         down(&parent->sem);
 824         list_del_init(&class_intf->node);
 825         if (class_intf->remove) {
 826                 list_for_each_entry(class_dev, &parent->children, node)
 827                         class_intf->remove(class_dev, class_intf);
 828         }
 829         if (class_intf->remove_dev) {
 830                 list_for_each_entry(dev, &parent->devices, node)
 831                         class_intf->remove_dev(dev, class_intf);
 832         }
 833         up(&parent->sem);
 834
 835         class_put(parent);
 836 }
 837
 838 int __init classes_init(void)
 839 {
 840         int retval;
 841
 842         retval = subsystem_register(&class_subsys);
 843         if (retval)
 844                 return retval;
 845
 846         /* ick, this is ugly, the things we go through to keep from showing up
 847          * in sysfs... */
 848         kset_init(&class_obj_subsys);
 849         if (!class_obj_subsys.kobj.parent)
 850                 class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
 851         return 0;
 852 }
 853
 854 EXPORT_SYMBOL_GPL(class_create_file);
 855 EXPORT_SYMBOL_GPL(class_remove_file);
 856 EXPORT_SYMBOL_GPL(class_register);
 857 EXPORT_SYMBOL_GPL(class_unregister);
 858 EXPORT_SYMBOL_GPL(class_create);
 859 EXPORT_SYMBOL_GPL(class_destroy);
 860
 861 EXPORT_SYMBOL_GPL(class_device_register);
 862 EXPORT_SYMBOL_GPL(class_device_unregister);
 863 EXPORT_SYMBOL_GPL(class_device_initialize);
 864 EXPORT_SYMBOL_GPL(class_device_add);
 865 EXPORT_SYMBOL_GPL(class_device_del);
 866 EXPORT_SYMBOL_GPL(class_device_get);
 867 EXPORT_SYMBOL_GPL(class_device_put);
 868 EXPORT_SYMBOL_GPL(class_device_create);
 869 EXPORT_SYMBOL_GPL(class_device_destroy);
 870 EXPORT_SYMBOL_GPL(class_device_create_file);
 871 EXPORT_SYMBOL_GPL(class_device_remove_file);
 872
 873 EXPORT_SYMBOL_GPL(class_interface_register);
 874 EXPORT_SYMBOL_GPL(class_interface_unregister);