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 <linux/genhd.h>
  21 #include "base.h"
  22
  23 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
  24 #define to_class(obj) container_of(obj, struct class, subsys.kobj)
  25
  26 static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
  27                                char *buf)
  28 {
  29         struct class_attribute *class_attr = to_class_attr(attr);
  30         struct class *dc = to_class(kobj);
  31         ssize_t ret = -EIO;
  32
  33         if (class_attr->show)
  34                 ret = class_attr->show(dc, buf);
  35         return ret;
  36 }
  37
  38 static ssize_t 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 struct kset *class_kset;
  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),
  97                                     struct class, subsys);
  98         return NULL;
  99 }
 100
 101 static void class_put(struct class *cls)
 102 {
 103         if (cls)
 104                 kset_put(&cls->subsys);
 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 error;
 117                 }
 118         }
 119 done:
 120         return error;
 121 error:
 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 #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)
 153         /* let the block class directory show up in the root of sysfs */
 154         if (cls != &block_class)
 155                 cls->subsys.kobj.kset = class_kset;
 156 #else
 157         cls->subsys.kobj.kset = class_kset;
 158 #endif
 159         cls->subsys.kobj.ktype = &class_ktype;
 160
 161         error = kset_register(&cls->subsys);
 162         if (!error) {
 163                 error = add_class_attrs(class_get(cls));
 164                 class_put(cls);
 165         }
 166         return error;
 167 }
 168
 169 void class_unregister(struct class *cls)
 170 {
 171         pr_debug("device class '%s': unregistering\n", cls->name);
 172         remove_class_attrs(cls);
 173         kset_unregister(&cls->subsys);
 174 }
 175
 176 static void class_create_release(struct class *cls)
 177 {
 178         pr_debug("%s called for %s\n", __func__, cls->name);
 179         kfree(cls);
 180 }
 181
 182 static void class_device_create_release(struct class_device *class_dev)
 183 {
 184         pr_debug("%s called for %s\n", __func__, class_dev->class_id);
 185         kfree(class_dev);
 186 }
 187
 188 /* needed to allow these devices to have parent class devices */
 189 static int class_device_create_uevent(struct class_device *class_dev,
 190                                       struct kobj_uevent_env *env)
 191 {
 192         pr_debug("%s called for %s\n", __func__, class_dev->class_id);
 193         return 0;
 194 }
 195
 196 /**
 197  * class_create - create a struct class structure
 198  * @owner: pointer to the module that is to "own" this struct class
 199  * @name: pointer to a string for the name of this class.
 200  *
 201  * This is used to create a struct class pointer that can then be used
 202  * in calls to class_device_create().
 203  *
 204  * Note, the pointer created here is to be destroyed when finished by
 205  * making a call to class_destroy().
 206  */
 207 struct class *class_create(struct module *owner, const char *name)
 208 {
 209         struct class *cls;
 210         int retval;
 211
 212         cls = kzalloc(sizeof(*cls), GFP_KERNEL);
 213         if (!cls) {
 214                 retval = -ENOMEM;
 215                 goto error;
 216         }
 217
 218         cls->name = name;
 219         cls->owner = owner;
 220         cls->class_release = class_create_release;
 221         cls->release = class_device_create_release;
 222
 223         retval = class_register(cls);
 224         if (retval)
 225                 goto error;
 226
 227         return cls;
 228
 229 error:
 230         kfree(cls);
 231         return ERR_PTR(retval);
 232 }
 233
 234 /**
 235  * class_destroy - destroys a struct class structure
 236  * @cls: pointer to the struct class that is to be destroyed
 237  *
 238  * Note, the pointer to be destroyed must have been created with a call
 239  * to class_create().
 240  */
 241 void class_destroy(struct class *cls)
 242 {
 243         if ((cls == NULL) || (IS_ERR(cls)))
 244                 return;
 245
 246         class_unregister(cls);
 247 }
 248
 249 /* Class Device Stuff */
 250
 251 int class_device_create_file(struct class_device *class_dev,
 252                              const struct class_device_attribute *attr)
 253 {
 254         int error = -EINVAL;
 255         if (class_dev)
 256                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 257         return error;
 258 }
 259
 260 void class_device_remove_file(struct class_device *class_dev,
 261                               const struct class_device_attribute *attr)
 262 {
 263         if (class_dev)
 264                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 265 }
 266
 267 int class_device_create_bin_file(struct class_device *class_dev,
 268                                  struct bin_attribute *attr)
 269 {
 270         int error = -EINVAL;
 271         if (class_dev)
 272                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
 273         return error;
 274 }
 275
 276 void class_device_remove_bin_file(struct class_device *class_dev,
 277                                   struct bin_attribute *attr)
 278 {
 279         if (class_dev)
 280                 sysfs_remove_bin_file(&class_dev->kobj, attr);
 281 }
 282
 283 static ssize_t class_device_attr_show(struct kobject *kobj,
 284                                       struct attribute *attr, char *buf)
 285 {
 286         struct class_device_attribute *class_dev_attr = to_class_dev_attr(attr);
 287         struct class_device *cd = to_class_dev(kobj);
 288         ssize_t ret = 0;
 289
 290         if (class_dev_attr->show)
 291                 ret = class_dev_attr->show(cd, buf);
 292         return ret;
 293 }
 294
 295 static ssize_t class_device_attr_store(struct kobject *kobj,
 296                                        struct attribute *attr,
 297                                        const char *buf, size_t count)
 298 {
 299         struct class_device_attribute *class_dev_attr = to_class_dev_attr(attr);
 300         struct class_device *cd = to_class_dev(kobj);
 301         ssize_t ret = 0;
 302
 303         if (class_dev_attr->store)
 304                 ret = class_dev_attr->store(cd, buf, count);
 305         return ret;
 306 }
 307
 308 static struct sysfs_ops class_dev_sysfs_ops = {
 309         .show   = class_device_attr_show,
 310         .store  = class_device_attr_store,
 311 };
 312
 313 static void class_dev_release(struct kobject *kobj)
 314 {
 315         struct class_device *cd = to_class_dev(kobj);
 316         struct class *cls = cd->class;
 317
 318         pr_debug("device class '%s': release.\n", cd->class_id);
 319
 320         if (cd->release)
 321                 cd->release(cd);
 322         else if (cls->release)
 323                 cls->release(cd);
 324         else {
 325                 printk(KERN_ERR "Class Device '%s' does not have a release() "
 326                         "function, it is broken and must be fixed.\n",
 327                         cd->class_id);
 328                 WARN_ON(1);
 329         }
 330 }
 331
 332 static struct kobj_type class_device_ktype = {
 333         .sysfs_ops      = &class_dev_sysfs_ops,
 334         .release        = class_dev_release,
 335 };
 336
 337 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
 338 {
 339         struct kobj_type *ktype = get_ktype(kobj);
 340
 341         if (ktype == &class_device_ktype) {
 342                 struct class_device *class_dev = to_class_dev(kobj);
 343                 if (class_dev->class)
 344                         return 1;
 345         }
 346         return 0;
 347 }
 348
 349 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
 350 {
 351         struct class_device *class_dev = to_class_dev(kobj);
 352
 353         return class_dev->class->name;
 354 }
 355
 356 #ifdef CONFIG_SYSFS_DEPRECATED
 357 char *make_class_name(const char *name, struct kobject *kobj)
 358 {
 359         char *class_name;
 360         int size;
 361
 362         size = strlen(name) + strlen(kobject_name(kobj)) + 2;
 363
 364         class_name = kmalloc(size, GFP_KERNEL);
 365         if (!class_name)
 366                 return NULL;
 367
 368         strcpy(class_name, name);
 369         strcat(class_name, ":");
 370         strcat(class_name, kobject_name(kobj));
 371         return class_name;
 372 }
 373
 374 static int make_deprecated_class_device_links(struct class_device *class_dev)
 375 {
 376         char *class_name;
 377         int error;
 378
 379         if (!class_dev->dev)
 380                 return 0;
 381
 382         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 383         if (class_name)
 384                 error = sysfs_create_link(&class_dev->dev->kobj,
 385                                           &class_dev->kobj, class_name);
 386         else
 387                 error = -ENOMEM;
 388         kfree(class_name);
 389         return error;
 390 }
 391
 392 static void remove_deprecated_class_device_links(struct class_device *class_dev)
 393 {
 394         char *class_name;
 395
 396         if (!class_dev->dev)
 397                 return;
 398
 399         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 400         if (class_name)
 401                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
 402         kfree(class_name);
 403 }
 404 #else
 405 static inline int make_deprecated_class_device_links(struct class_device *cd)
 406 { return 0; }
 407 static void remove_deprecated_class_device_links(struct class_device *cd)
 408 { }
 409 #endif
 410
 411 static int class_uevent(struct kset *kset, struct kobject *kobj,
 412                         struct kobj_uevent_env *env)
 413 {
 414         struct class_device *class_dev = to_class_dev(kobj);
 415         struct device *dev = class_dev->dev;
 416         int retval = 0;
 417
 418         pr_debug("%s - name = %s\n", __func__, class_dev->class_id);
 419
 420         if (MAJOR(class_dev->devt)) {
 421                 add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt));
 422
 423                 add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt));
 424         }
 425
 426         if (dev) {
 427                 const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 428                 if (path) {
 429                         add_uevent_var(env, "PHYSDEVPATH=%s", path);
 430                         kfree(path);
 431                 }
 432
 433                 if (dev->bus)
 434                         add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
 435
 436                 if (dev->driver)
 437                         add_uevent_var(env, "PHYSDEVDRIVER=%s",
 438                                        dev->driver->name);
 439         }
 440
 441         if (class_dev->uevent) {
 442                 /* have the class device specific function add its stuff */
 443                 retval = class_dev->uevent(class_dev, env);
 444                 if (retval)
 445                         pr_debug("class_dev->uevent() returned %d\n", retval);
 446         } else if (class_dev->class->uevent) {
 447                 /* have the class specific function add its stuff */
 448                 retval = class_dev->class->uevent(class_dev, env);
 449                 if (retval)
 450                         pr_debug("class->uevent() returned %d\n", retval);
 451         }
 452
 453         return retval;
 454 }
 455
 456 static struct kset_uevent_ops class_uevent_ops = {
 457         .filter =       class_uevent_filter,
 458         .name =         class_uevent_name,
 459         .uevent =       class_uevent,
 460 };
 461
 462 /*
 463  * DO NOT copy how this is created, kset_create_and_add() should be
 464  * called, but this is a hold-over from the old-way and will be deleted
 465  * entirely soon.
 466  */
 467 static struct kset class_obj_subsys = {
 468         .uevent_ops = &class_uevent_ops,
 469 };
 470
 471 static int class_device_add_attrs(struct class_device *cd)
 472 {
 473         int i;
 474         int error = 0;
 475         struct class *cls = cd->class;
 476
 477         if (cls->class_dev_attrs) {
 478                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 479                         error = class_device_create_file(cd,
 480                                                 &cls->class_dev_attrs[i]);
 481                         if (error)
 482                                 goto err;
 483                 }
 484         }
 485 done:
 486         return error;
 487 err:
 488         while (--i >= 0)
 489                 class_device_remove_file(cd, &cls->class_dev_attrs[i]);
 490         goto done;
 491 }
 492
 493 static void class_device_remove_attrs(struct class_device *cd)
 494 {
 495         int i;
 496         struct class *cls = cd->class;
 497
 498         if (cls->class_dev_attrs) {
 499                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 500                         class_device_remove_file(cd, &cls->class_dev_attrs[i]);
 501         }
 502 }
 503
 504 static int class_device_add_groups(struct class_device *cd)
 505 {
 506         int i;
 507         int error = 0;
 508
 509         if (cd->groups) {
 510                 for (i = 0; cd->groups[i]; i++) {
 511                         error = sysfs_create_group(&cd->kobj, cd->groups[i]);
 512                         if (error) {
 513                                 while (--i >= 0)
 514                                         sysfs_remove_group(&cd->kobj,
 515                                                            cd->groups[i]);
 516                                 goto out;
 517                         }
 518                 }
 519         }
 520 out:
 521         return error;
 522 }
 523
 524 static void class_device_remove_groups(struct class_device *cd)
 525 {
 526         int i;
 527         if (cd->groups)
 528                 for (i = 0; cd->groups[i]; i++)
 529                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 530 }
 531
 532 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 533 {
 534         return print_dev_t(buf, class_dev->devt);
 535 }
 536
 537 static struct class_device_attribute class_devt_attr =
 538         __ATTR(dev, S_IRUGO, show_dev, NULL);
 539
 540 static ssize_t store_uevent(struct class_device *class_dev,
 541                             const char *buf, size_t count)
 542 {
 543         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 544         return count;
 545 }
 546
 547 static struct class_device_attribute class_uevent_attr =
 548         __ATTR(uevent, S_IWUSR, NULL, store_uevent);
 549
 550 void class_device_initialize(struct class_device *class_dev)
 551 {
 552         class_dev->kobj.kset = &class_obj_subsys;
 553         kobject_init(&class_dev->kobj, &class_device_ktype);
 554         INIT_LIST_HEAD(&class_dev->node);
 555 }
 556
 557 int class_device_add(struct class_device *class_dev)
 558 {
 559         struct class *parent_class = NULL;
 560         struct class_device *parent_class_dev = NULL;
 561         struct class_interface *class_intf;
 562         int error = -EINVAL;
 563
 564         class_dev = class_device_get(class_dev);
 565         if (!class_dev)
 566                 return -EINVAL;
 567
 568         if (!strlen(class_dev->class_id))
 569                 goto out1;
 570
 571         parent_class = class_get(class_dev->class);
 572         if (!parent_class)
 573                 goto out1;
 574
 575         parent_class_dev = class_device_get(class_dev->parent);
 576
 577         pr_debug("CLASS: registering class device: ID = '%s'\n",
 578                  class_dev->class_id);
 579
 580         /* first, register with generic layer. */
 581         if (parent_class_dev)
 582                 class_dev->kobj.parent = &parent_class_dev->kobj;
 583         else
 584                 class_dev->kobj.parent = &parent_class->subsys.kobj;
 585
 586         error = kobject_add(&class_dev->kobj, class_dev->kobj.parent,
 587                             "%s", class_dev->class_id);
 588         if (error)
 589                 goto out2;
 590
 591         /* add the needed attributes to this device */
 592         error = sysfs_create_link(&class_dev->kobj,
 593                                   &parent_class->subsys.kobj, "subsystem");
 594         if (error)
 595                 goto out3;
 596
 597         error = class_device_create_file(class_dev, &class_uevent_attr);
 598         if (error)
 599                 goto out3;
 600
 601         if (MAJOR(class_dev->devt)) {
 602                 error = class_device_create_file(class_dev, &class_devt_attr);
 603                 if (error)
 604                         goto out4;
 605         }
 606
 607         error = class_device_add_attrs(class_dev);
 608         if (error)
 609                 goto out5;
 610
 611         if (class_dev->dev) {
 612                 error = sysfs_create_link(&class_dev->kobj,
 613                                           &class_dev->dev->kobj, "device");
 614                 if (error)
 615                         goto out6;
 616         }
 617
 618         error = class_device_add_groups(class_dev);
 619         if (error)
 620                 goto out7;
 621
 622         error = make_deprecated_class_device_links(class_dev);
 623         if (error)
 624                 goto out8;
 625
 626         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 627
 628         /* notify any interfaces this device is now here */
 629         down(&parent_class->sem);
 630         list_add_tail(&class_dev->node, &parent_class->children);
 631         list_for_each_entry(class_intf, &parent_class->interfaces, node) {
 632                 if (class_intf->add)
 633                         class_intf->add(class_dev, class_intf);
 634         }
 635         up(&parent_class->sem);
 636
 637         goto out1;
 638
 639  out8:
 640         class_device_remove_groups(class_dev);
 641  out7:
 642         if (class_dev->dev)
 643                 sysfs_remove_link(&class_dev->kobj, "device");
 644  out6:
 645         class_device_remove_attrs(class_dev);
 646  out5:
 647         if (MAJOR(class_dev->devt))
 648                 class_device_remove_file(class_dev, &class_devt_attr);
 649  out4:
 650         class_device_remove_file(class_dev, &class_uevent_attr);
 651  out3:
 652         kobject_del(&class_dev->kobj);
 653  out2:
 654         if (parent_class_dev)
 655                 class_device_put(parent_class_dev);
 656         class_put(parent_class);
 657  out1:
 658         class_device_put(class_dev);
 659         return error;
 660 }
 661
 662 int class_device_register(struct class_device *class_dev)
 663 {
 664         class_device_initialize(class_dev);
 665         return class_device_add(class_dev);
 666 }
 667
 668 /**
 669  * class_device_create - creates a class device and registers it with sysfs
 670  * @cls: pointer to the struct class that this device should be registered to.
 671  * @parent: pointer to the parent struct class_device of this new device, if
 672  * any.
 673  * @devt: the dev_t for the char device to be added.
 674  * @device: a pointer to a struct device that is assiociated with this class
 675  * device.
 676  * @fmt: string for the class device's name
 677  *
 678  * This function can be used by char device classes.  A struct
 679  * class_device will be created in sysfs, registered to the specified
 680  * class.
 681  * A "dev" file will be created, showing the dev_t for the device, if
 682  * the dev_t is not 0,0.
 683  * If a pointer to a parent struct class_device is passed in, the newly
 684  * created struct class_device will be a child of that device in sysfs.
 685  * The pointer to the struct class_device will be returned from the
 686  * call.  Any further sysfs files that might be required can be created
 687  * using this pointer.
 688  *
 689  * Note: the struct class passed to this function must have previously
 690  * been created with a call to class_create().
 691  */
 692 struct class_device *class_device_create(struct class *cls,
 693                                          struct class_device *parent,
 694                                          dev_t devt,
 695                                          struct device *device,
 696                                          const char *fmt, ...)
 697 {
 698         va_list args;
 699         struct class_device *class_dev = NULL;
 700         int retval = -ENODEV;
 701
 702         if (cls == NULL || IS_ERR(cls))
 703                 goto error;
 704
 705         class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
 706         if (!class_dev) {
 707                 retval = -ENOMEM;
 708                 goto error;
 709         }
 710
 711         class_dev->devt = devt;
 712         class_dev->dev = device;
 713         class_dev->class = cls;
 714         class_dev->parent = parent;
 715         class_dev->release = class_device_create_release;
 716         class_dev->uevent = class_device_create_uevent;
 717
 718         va_start(args, fmt);
 719         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
 720         va_end(args);
 721         retval = class_device_register(class_dev);
 722         if (retval)
 723                 goto error;
 724
 725         return class_dev;
 726
 727 error:
 728         kfree(class_dev);
 729         return ERR_PTR(retval);
 730 }
 731
 732 void class_device_del(struct class_device *class_dev)
 733 {
 734         struct class *parent_class = class_dev->class;
 735         struct class_device *parent_device = class_dev->parent;
 736         struct class_interface *class_intf;
 737
 738         if (parent_class) {
 739                 down(&parent_class->sem);
 740                 list_del_init(&class_dev->node);
 741                 list_for_each_entry(class_intf, &parent_class->interfaces, node)
 742                         if (class_intf->remove)
 743                                 class_intf->remove(class_dev, class_intf);
 744                 up(&parent_class->sem);
 745         }
 746
 747         if (class_dev->dev) {
 748                 remove_deprecated_class_device_links(class_dev);
 749                 sysfs_remove_link(&class_dev->kobj, "device");
 750         }
 751         sysfs_remove_link(&class_dev->kobj, "subsystem");
 752         class_device_remove_file(class_dev, &class_uevent_attr);
 753         if (MAJOR(class_dev->devt))
 754                 class_device_remove_file(class_dev, &class_devt_attr);
 755         class_device_remove_attrs(class_dev);
 756         class_device_remove_groups(class_dev);
 757
 758         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
 759         kobject_del(&class_dev->kobj);
 760
 761         class_device_put(parent_device);
 762         class_put(parent_class);
 763 }
 764
 765 void class_device_unregister(struct class_device *class_dev)
 766 {
 767         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 768                  class_dev->class_id);
 769         class_device_del(class_dev);
 770         class_device_put(class_dev);
 771 }
 772
 773 /**
 774  * class_device_destroy - removes a class device that was created with class_device_create()
 775  * @cls: the pointer to the struct class that this device was registered * with.
 776  * @devt: the dev_t of the device that was previously registered.
 777  *
 778  * This call unregisters and cleans up a class device that was created with a
 779  * call to class_device_create()
 780  */
 781 void class_device_destroy(struct class *cls, dev_t devt)
 782 {
 783         struct class_device *class_dev = NULL;
 784         struct class_device *class_dev_tmp;
 785
 786         down(&cls->sem);
 787         list_for_each_entry(class_dev_tmp, &cls->children, node) {
 788                 if (class_dev_tmp->devt == devt) {
 789                         class_dev = class_dev_tmp;
 790                         break;
 791                 }
 792         }
 793         up(&cls->sem);
 794
 795         if (class_dev)
 796                 class_device_unregister(class_dev);
 797 }
 798
 799 struct class_device *class_device_get(struct class_device *class_dev)
 800 {
 801         if (class_dev)
 802                 return to_class_dev(kobject_get(&class_dev->kobj));
 803         return NULL;
 804 }
 805
 806 void class_device_put(struct class_device *class_dev)
 807 {
 808         if (class_dev)
 809                 kobject_put(&class_dev->kobj);
 810 }
 811
 812 /**
 813  * class_for_each_device - device iterator
 814  * @class: the class we're iterating
 815  * @data: data for the callback
 816  * @fn: function to be called for each device
 817  *
 818  * Iterate over @class's list of devices, and call @fn for each,
 819  * passing it @data.
 820  *
 821  * We check the return of @fn each time. If it returns anything
 822  * other than 0, we break out and return that value.
 823  *
 824  * Note, we hold class->sem in this function, so it can not be
 825  * re-acquired in @fn, otherwise it will self-deadlocking. For
 826  * example, calls to add or remove class members would be verboten.
 827  */
 828 int class_for_each_device(struct class *class, void *data,
 829                            int (*fn)(struct device *, void *))
 830 {
 831         struct device *dev;
 832         int error = 0;
 833
 834         if (!class)
 835                 return -EINVAL;
 836         down(&class->sem);
 837         list_for_each_entry(dev, &class->devices, node) {
 838                 dev = get_device(dev);
 839                 if (dev) {
 840                         error = fn(dev, data);
 841                         put_device(dev);
 842                 } else
 843                         error = -ENODEV;
 844                 if (error)
 845                         break;
 846         }
 847         up(&class->sem);
 848
 849         return error;
 850 }
 851 EXPORT_SYMBOL_GPL(class_for_each_device);
 852
 853 /**
 854  * class_find_device - device iterator for locating a particular device
 855  * @class: the class we're iterating
 856  * @data: data for the match function
 857  * @match: function to check device
 858  *
 859  * This is similar to the class_for_each_dev() function above, but it
 860  * returns a reference to a device that is 'found' for later use, as
 861  * determined by the @match callback.
 862  *
 863  * The callback should return 0 if the device doesn't match and non-zero
 864  * if it does.  If the callback returns non-zero, this function will
 865  * return to the caller and not iterate over any more devices.
 866  *
 867  * Note, you will need to drop the reference with put_device() after use.
 868  *
 869  * We hold class->sem in this function, so it can not be
 870  * re-acquired in @match, otherwise it will self-deadlocking. For
 871  * example, calls to add or remove class members would be verboten.
 872  */
 873 struct device *class_find_device(struct class *class, void *data,
 874                                    int (*match)(struct device *, void *))
 875 {
 876         struct device *dev;
 877         int found = 0;
 878
 879         if (!class)
 880                 return NULL;
 881
 882         down(&class->sem);
 883         list_for_each_entry(dev, &class->devices, node) {
 884                 dev = get_device(dev);
 885                 if (dev) {
 886                         if (match(dev, data)) {
 887                                 found = 1;
 888                                 break;
 889                         } else
 890                                 put_device(dev);
 891                 } else
 892                         break;
 893         }
 894         up(&class->sem);
 895
 896         return found ? dev : NULL;
 897 }
 898 EXPORT_SYMBOL_GPL(class_find_device);
 899
 900 /**
 901  * class_find_child - device iterator for locating a particular class_device
 902  * @class: the class we're iterating
 903  * @data: data for the match function
 904  * @match: function to check class_device
 905  *
 906  * This function returns a reference to a class_device that is 'found' for
 907  * later use, as determined by the @match callback.
 908  *
 909  * The callback should return 0 if the class_device doesn't match and non-zero
 910  * if it does.  If the callback returns non-zero, this function will
 911  * return to the caller and not iterate over any more class_devices.
 912  *
 913  * Note, you will need to drop the reference with class_device_put() after use.
 914  *
 915  * We hold class->sem in this function, so it can not be
 916  * re-acquired in @match, otherwise it will self-deadlocking. For
 917  * example, calls to add or remove class members would be verboten.
 918  */
 919 struct class_device *class_find_child(struct class *class, void *data,
 920                                    int (*match)(struct class_device *, void *))
 921 {
 922         struct class_device *dev;
 923         int found = 0;
 924
 925         if (!class)
 926                 return NULL;
 927
 928         down(&class->sem);
 929         list_for_each_entry(dev, &class->children, node) {
 930                 dev = class_device_get(dev);
 931                 if (dev) {
 932                         if (match(dev, data)) {
 933                                 found = 1;
 934                                 break;
 935                         } else
 936                                 class_device_put(dev);
 937                 } else
 938                         break;
 939         }
 940         up(&class->sem);
 941
 942         return found ? dev : NULL;
 943 }
 944 EXPORT_SYMBOL_GPL(class_find_child);
 945
 946 int class_interface_register(struct class_interface *class_intf)
 947 {
 948         struct class *parent;
 949         struct class_device *class_dev;
 950         struct device *dev;
 951
 952         if (!class_intf || !class_intf->class)
 953                 return -ENODEV;
 954
 955         parent = class_get(class_intf->class);
 956         if (!parent)
 957                 return -EINVAL;
 958
 959         down(&parent->sem);
 960         list_add_tail(&class_intf->node, &parent->interfaces);
 961         if (class_intf->add) {
 962                 list_for_each_entry(class_dev, &parent->children, node)
 963                         class_intf->add(class_dev, class_intf);
 964         }
 965         if (class_intf->add_dev) {
 966                 list_for_each_entry(dev, &parent->devices, node)
 967                         class_intf->add_dev(dev, class_intf);
 968         }
 969         up(&parent->sem);
 970
 971         return 0;
 972 }
 973
 974 void class_interface_unregister(struct class_interface *class_intf)
 975 {
 976         struct class *parent = class_intf->class;
 977         struct class_device *class_dev;
 978         struct device *dev;
 979
 980         if (!parent)
 981                 return;
 982
 983         down(&parent->sem);
 984         list_del_init(&class_intf->node);
 985         if (class_intf->remove) {
 986                 list_for_each_entry(class_dev, &parent->children, node)
 987                         class_intf->remove(class_dev, class_intf);
 988         }
 989         if (class_intf->remove_dev) {
 990                 list_for_each_entry(dev, &parent->devices, node)
 991                         class_intf->remove_dev(dev, class_intf);
 992         }
 993         up(&parent->sem);
 994
 995         class_put(parent);
 996 }
 997
 998 int __init classes_init(void)
 999 {
1000         class_kset = kset_create_and_add("class", NULL, NULL);
1001         if (!class_kset)
1002                 return -ENOMEM;
1003
1004         /* ick, this is ugly, the things we go through to keep from showing up
1005          * in sysfs... */
1006         kset_init(&class_obj_subsys);
1007         kobject_set_name(&class_obj_subsys.kobj, "class_obj");
1008         if (!class_obj_subsys.kobj.parent)
1009                 class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
1010         return 0;
1011 }
1012
1013 EXPORT_SYMBOL_GPL(class_create_file);
1014 EXPORT_SYMBOL_GPL(class_remove_file);
1015 EXPORT_SYMBOL_GPL(class_register);
1016 EXPORT_SYMBOL_GPL(class_unregister);
1017 EXPORT_SYMBOL_GPL(class_create);
1018 EXPORT_SYMBOL_GPL(class_destroy);
1019
1020 EXPORT_SYMBOL_GPL(class_device_register);
1021 EXPORT_SYMBOL_GPL(class_device_unregister);
1022 EXPORT_SYMBOL_GPL(class_device_initialize);
1023 EXPORT_SYMBOL_GPL(class_device_add);
1024 EXPORT_SYMBOL_GPL(class_device_del);
1025 EXPORT_SYMBOL_GPL(class_device_get);
1026 EXPORT_SYMBOL_GPL(class_device_put);
1027 EXPORT_SYMBOL_GPL(class_device_create);
1028 EXPORT_SYMBOL_GPL(class_device_destroy);
1029 EXPORT_SYMBOL_GPL(class_device_create_file);
1030 EXPORT_SYMBOL_GPL(class_device_remove_file);
1031 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
1032 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
1033
1034 EXPORT_SYMBOL_GPL(class_interface_register);
1035 EXPORT_SYMBOL_GPL(class_interface_unregister);