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 extern struct subsystem devices_subsys;
  23
  24 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
  25 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
  26
  27 static ssize_t
  28 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
  29 {
  30         struct class_attribute * class_attr = to_class_attr(attr);
  31         struct class * dc = to_class(kobj);
  32         ssize_t ret = -EIO;
  33
  34         if (class_attr->show)
  35                 ret = class_attr->show(dc, buf);
  36         return ret;
  37 }
  38
  39 static ssize_t
  40 class_attr_store(struct kobject * kobj, struct attribute * attr,
  41                  const char * buf, size_t count)
  42 {
  43         struct class_attribute * class_attr = to_class_attr(attr);
  44         struct class * dc = to_class(kobj);
  45         ssize_t ret = -EIO;
  46
  47         if (class_attr->store)
  48                 ret = class_attr->store(dc, buf, count);
  49         return ret;
  50 }
  51
  52 static void class_release(struct kobject * kobj)
  53 {
  54         struct class *class = to_class(kobj);
  55
  56         pr_debug("class '%s': release.\n", class->name);
  57
  58         if (class->class_release)
  59                 class->class_release(class);
  60         else
  61                 pr_debug("class '%s' does not have a release() function, "
  62                          "be careful\n", class->name);
  63 }
  64
  65 static struct sysfs_ops class_sysfs_ops = {
  66         .show   = class_attr_show,
  67         .store  = class_attr_store,
  68 };
  69
  70 static struct kobj_type ktype_class = {
  71         .sysfs_ops      = &class_sysfs_ops,
  72         .release        = class_release,
  73 };
  74
  75 /* Hotplug events for classes go to the class_obj subsys */
  76 static decl_subsys(class, &ktype_class, NULL);
  77
  78
  79 int class_create_file(struct class * cls, const struct class_attribute * attr)
  80 {
  81         int error;
  82         if (cls) {
  83                 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
  84         } else
  85                 error = -EINVAL;
  86         return error;
  87 }
  88
  89 void class_remove_file(struct class * cls, const struct class_attribute * attr)
  90 {
  91         if (cls)
  92                 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
  93 }
  94
  95 static struct class *class_get(struct class *cls)
  96 {
  97         if (cls)
  98                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
  99         return NULL;
 100 }
 101
 102 static void class_put(struct class * cls)
 103 {
 104         if (cls)
 105                 subsys_put(&cls->subsys);
 106 }
 107
 108
 109 static int add_class_attrs(struct class * cls)
 110 {
 111         int i;
 112         int error = 0;
 113
 114         if (cls->class_attrs) {
 115                 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
 116                         error = class_create_file(cls,&cls->class_attrs[i]);
 117                         if (error)
 118                                 goto Err;
 119                 }
 120         }
 121  Done:
 122         return error;
 123  Err:
 124         while (--i >= 0)
 125                 class_remove_file(cls,&cls->class_attrs[i]);
 126         goto Done;
 127 }
 128
 129 static void remove_class_attrs(struct class * cls)
 130 {
 131         int i;
 132
 133         if (cls->class_attrs) {
 134                 for (i = 0; attr_name(cls->class_attrs[i]); i++)
 135                         class_remove_file(cls,&cls->class_attrs[i]);
 136         }
 137 }
 138
 139 int class_register(struct class * cls)
 140 {
 141         int error;
 142
 143         pr_debug("device class '%s': registering\n", cls->name);
 144
 145         INIT_LIST_HEAD(&cls->children);
 146         INIT_LIST_HEAD(&cls->devices);
 147         INIT_LIST_HEAD(&cls->interfaces);
 148         init_MUTEX(&cls->sem);
 149         error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
 150         if (error)
 151                 return error;
 152
 153         subsys_set_kset(cls, class_subsys);
 154
 155         error = subsystem_register(&cls->subsys);
 156         if (!error) {
 157                 error = add_class_attrs(class_get(cls));
 158                 class_put(cls);
 159         }
 160         return error;
 161 }
 162
 163 void class_unregister(struct class * cls)
 164 {
 165         pr_debug("device class '%s': unregistering\n", cls->name);
 166         if (cls->virtual_dir)
 167                 kobject_unregister(cls->virtual_dir);
 168         remove_class_attrs(cls);
 169         subsystem_unregister(&cls->subsys);
 170 }
 171
 172 static void class_create_release(struct class *cls)
 173 {
 174         pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
 175         kfree(cls);
 176 }
 177
 178 static void class_device_create_release(struct class_device *class_dev)
 179 {
 180         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
 181         kfree(class_dev);
 182 }
 183
 184 /* needed to allow these devices to have parent class devices */
 185 static int class_device_create_uevent(struct class_device *class_dev,
 186                                        char **envp, int num_envp,
 187                                        char *buffer, int buffer_size)
 188 {
 189         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
 190         return 0;
 191 }
 192
 193 /**
 194  * class_create - create a struct class structure
 195  * @owner: pointer to the module that is to "own" this struct class
 196  * @name: pointer to a string for the name of this class.
 197  *
 198  * This is used to create a struct class pointer that can then be used
 199  * in calls to class_device_create().
 200  *
 201  * Note, the pointer created here is to be destroyed when finished by
 202  * making a call to class_destroy().
 203  */
 204 struct class *class_create(struct module *owner, const char *name)
 205 {
 206         struct class *cls;
 207         int retval;
 208
 209         cls = kzalloc(sizeof(*cls), GFP_KERNEL);
 210         if (!cls) {
 211                 retval = -ENOMEM;
 212                 goto error;
 213         }
 214
 215         cls->name = name;
 216         cls->owner = owner;
 217         cls->class_release = class_create_release;
 218         cls->release = class_device_create_release;
 219
 220         retval = class_register(cls);
 221         if (retval)
 222                 goto error;
 223
 224         return cls;
 225
 226 error:
 227         kfree(cls);
 228         return ERR_PTR(retval);
 229 }
 230
 231 /**
 232  * class_destroy - destroys a struct class structure
 233  * @cls: pointer to the struct class that is to be destroyed
 234  *
 235  * Note, the pointer to be destroyed must have been created with a call
 236  * to class_create().
 237  */
 238 void class_destroy(struct class *cls)
 239 {
 240         if ((cls == NULL) || (IS_ERR(cls)))
 241                 return;
 242
 243         class_unregister(cls);
 244 }
 245
 246 /* Class Device Stuff */
 247
 248 int class_device_create_file(struct class_device * class_dev,
 249                              const struct class_device_attribute * attr)
 250 {
 251         int error = -EINVAL;
 252         if (class_dev)
 253                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 254         return error;
 255 }
 256
 257 void class_device_remove_file(struct class_device * class_dev,
 258                               const struct class_device_attribute * attr)
 259 {
 260         if (class_dev)
 261                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 262 }
 263
 264 int class_device_create_bin_file(struct class_device *class_dev,
 265                                  struct bin_attribute *attr)
 266 {
 267         int error = -EINVAL;
 268         if (class_dev)
 269                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
 270         return error;
 271 }
 272
 273 void class_device_remove_bin_file(struct class_device *class_dev,
 274                                   struct bin_attribute *attr)
 275 {
 276         if (class_dev)
 277                 sysfs_remove_bin_file(&class_dev->kobj, attr);
 278 }
 279
 280 static ssize_t
 281 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 282                        char * buf)
 283 {
 284         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 285         struct class_device * cd = to_class_dev(kobj);
 286         ssize_t ret = 0;
 287
 288         if (class_dev_attr->show)
 289                 ret = class_dev_attr->show(cd, buf);
 290         return ret;
 291 }
 292
 293 static ssize_t
 294 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 295                         const char * buf, size_t count)
 296 {
 297         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 298         struct class_device * cd = to_class_dev(kobj);
 299         ssize_t ret = 0;
 300
 301         if (class_dev_attr->store)
 302                 ret = class_dev_attr->store(cd, buf, count);
 303         return ret;
 304 }
 305
 306 static struct sysfs_ops class_dev_sysfs_ops = {
 307         .show   = class_device_attr_show,
 308         .store  = class_device_attr_store,
 309 };
 310
 311 static void class_dev_release(struct kobject * kobj)
 312 {
 313         struct class_device *cd = to_class_dev(kobj);
 314         struct class * cls = cd->class;
 315
 316         pr_debug("device class '%s': release.\n", cd->class_id);
 317
 318         kfree(cd->devt_attr);
 319         cd->devt_attr = NULL;
 320
 321         if (cd->release)
 322                 cd->release(cd);
 323         else if (cls->release)
 324                 cls->release(cd);
 325         else {
 326                 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
 327                         "it is broken and must be fixed.\n",
 328                         cd->class_id);
 329                 WARN_ON(1);
 330         }
 331 }
 332
 333 static struct kobj_type ktype_class_device = {
 334         .sysfs_ops      = &class_dev_sysfs_ops,
 335         .release        = class_dev_release,
 336 };
 337
 338 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
 339 {
 340         struct kobj_type *ktype = get_ktype(kobj);
 341
 342         if (ktype == &ktype_class_device) {
 343                 struct class_device *class_dev = to_class_dev(kobj);
 344                 if (class_dev->class)
 345                         return 1;
 346         }
 347         return 0;
 348 }
 349
 350 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
 351 {
 352         struct class_device *class_dev = to_class_dev(kobj);
 353
 354         return class_dev->class->name;
 355 }
 356
 357 #ifdef CONFIG_SYSFS_DEPRECATED
 358 char *make_class_name(const char *name, struct kobject *kobj)
 359 {
 360         char *class_name;
 361         int size;
 362
 363         size = strlen(name) + strlen(kobject_name(kobj)) + 2;
 364
 365         class_name = kmalloc(size, GFP_KERNEL);
 366         if (!class_name)
 367                 return NULL;
 368
 369         strcpy(class_name, name);
 370         strcat(class_name, ":");
 371         strcat(class_name, kobject_name(kobj));
 372         return class_name;
 373 }
 374
 375 static int deprecated_class_uevent(char **envp, int num_envp, int *cur_index,
 376                                    char *buffer, int buffer_size,
 377                                    int *cur_len,
 378                                    struct class_device *class_dev)
 379 {
 380         struct device *dev = class_dev->dev;
 381         char *path;
 382
 383         if (!dev)
 384                 return 0;
 385
 386         /* add device, backing this class device (deprecated) */
 387         path = kobject_get_path(&dev->kobj, GFP_KERNEL);
 388
 389         add_uevent_var(envp, num_envp, cur_index, buffer, buffer_size,
 390                        cur_len, "PHYSDEVPATH=%s", path);
 391         kfree(path);
 392
 393         if (dev->bus)
 394                 add_uevent_var(envp, num_envp, cur_index,
 395                                buffer, buffer_size, cur_len,
 396                                "PHYSDEVBUS=%s", dev->bus->name);
 397
 398         if (dev->driver)
 399                 add_uevent_var(envp, num_envp, cur_index,
 400                                buffer, buffer_size, cur_len,
 401                                "PHYSDEVDRIVER=%s", dev->driver->name);
 402         return 0;
 403 }
 404
 405 static int make_deprecated_class_device_links(struct class_device *class_dev)
 406 {
 407         char *class_name;
 408         int error;
 409
 410         if (!class_dev->dev)
 411                 return 0;
 412
 413         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 414         if (class_name)
 415                 error = sysfs_create_link(&class_dev->dev->kobj,
 416                                           &class_dev->kobj, class_name);
 417         else
 418                 error = -ENOMEM;
 419         kfree(class_name);
 420         return error;
 421 }
 422
 423 static void remove_deprecated_class_device_links(struct class_device *class_dev)
 424 {
 425         char *class_name;
 426
 427         if (!class_dev->dev)
 428                 return;
 429
 430         class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
 431         if (class_name)
 432                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
 433         kfree(class_name);
 434 }
 435 #else
 436 static inline int deprecated_class_uevent(char **envp, int num_envp,
 437                                           int *cur_index, char *buffer,
 438                                           int buffer_size, int *cur_len,
 439                                           struct class_device *class_dev)
 440 { return 0; }
 441 static inline int make_deprecated_class_device_links(struct class_device *cd)
 442 { return 0; }
 443 static void remove_deprecated_class_device_links(struct class_device *cd)
 444 { }
 445 #endif
 446
 447 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
 448                          int num_envp, char *buffer, int buffer_size)
 449 {
 450         struct class_device *class_dev = to_class_dev(kobj);
 451         int i = 0;
 452         int length = 0;
 453         int retval = 0;
 454
 455         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 456
 457         deprecated_class_uevent(envp, num_envp, &i, buffer, buffer_size,
 458                                 &length, class_dev);
 459
 460         if (MAJOR(class_dev->devt)) {
 461                 add_uevent_var(envp, num_envp, &i,
 462                                buffer, buffer_size, &length,
 463                                "MAJOR=%u", MAJOR(class_dev->devt));
 464
 465                 add_uevent_var(envp, num_envp, &i,
 466                                buffer, buffer_size, &length,
 467                                "MINOR=%u", MINOR(class_dev->devt));
 468         }
 469
 470         /* terminate, set to next free slot, shrink available space */
 471         envp[i] = NULL;
 472         envp = &envp[i];
 473         num_envp -= i;
 474         buffer = &buffer[length];
 475         buffer_size -= length;
 476
 477         if (class_dev->uevent) {
 478                 /* have the class device specific function add its stuff */
 479                 retval = class_dev->uevent(class_dev, envp, num_envp,
 480                                             buffer, buffer_size);
 481                 if (retval)
 482                         pr_debug("class_dev->uevent() returned %d\n", retval);
 483         } else if (class_dev->class->uevent) {
 484                 /* have the class specific function add its stuff */
 485                 retval = class_dev->class->uevent(class_dev, envp, num_envp,
 486                                                    buffer, buffer_size);
 487                 if (retval)
 488                         pr_debug("class->uevent() returned %d\n", retval);
 489         }
 490
 491         return retval;
 492 }
 493
 494 static struct kset_uevent_ops class_uevent_ops = {
 495         .filter =       class_uevent_filter,
 496         .name =         class_uevent_name,
 497         .uevent =       class_uevent,
 498 };
 499
 500 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
 501
 502
 503 static int class_device_add_attrs(struct class_device * cd)
 504 {
 505         int i;
 506         int error = 0;
 507         struct class * cls = cd->class;
 508
 509         if (cls->class_dev_attrs) {
 510                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 511                         error = class_device_create_file(cd,
 512                                                          &cls->class_dev_attrs[i]);
 513                         if (error)
 514                                 goto Err;
 515                 }
 516         }
 517  Done:
 518         return error;
 519  Err:
 520         while (--i >= 0)
 521                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 522         goto Done;
 523 }
 524
 525 static void class_device_remove_attrs(struct class_device * cd)
 526 {
 527         int i;
 528         struct class * cls = cd->class;
 529
 530         if (cls->class_dev_attrs) {
 531                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 532                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 533         }
 534 }
 535
 536 static int class_device_add_groups(struct class_device * cd)
 537 {
 538         int i;
 539         int error = 0;
 540
 541         if (cd->groups) {
 542                 for (i = 0; cd->groups[i]; i++) {
 543                         error = sysfs_create_group(&cd->kobj, cd->groups[i]);
 544                         if (error) {
 545                                 while (--i >= 0)
 546                                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 547                                 goto out;
 548                         }
 549                 }
 550         }
 551 out:
 552         return error;
 553 }
 554
 555 static void class_device_remove_groups(struct class_device * cd)
 556 {
 557         int i;
 558         if (cd->groups) {
 559                 for (i = 0; cd->groups[i]; i++) {
 560                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
 561                 }
 562         }
 563 }
 564
 565 static ssize_t show_dev(struct class_device *class_dev, char *buf)
 566 {
 567         return print_dev_t(buf, class_dev->devt);
 568 }
 569
 570 static ssize_t store_uevent(struct class_device *class_dev,
 571                             const char *buf, size_t count)
 572 {
 573         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 574         return count;
 575 }
 576
 577 void class_device_initialize(struct class_device *class_dev)
 578 {
 579         kobj_set_kset_s(class_dev, class_obj_subsys);
 580         kobject_init(&class_dev->kobj);
 581         INIT_LIST_HEAD(&class_dev->node);
 582 }
 583
 584 int class_device_add(struct class_device *class_dev)
 585 {
 586         struct class *parent_class = NULL;
 587         struct class_device *parent_class_dev = NULL;
 588         struct class_interface *class_intf;
 589         int error = -EINVAL;
 590
 591         class_dev = class_device_get(class_dev);
 592         if (!class_dev)
 593                 return -EINVAL;
 594
 595         if (!strlen(class_dev->class_id))
 596                 goto out1;
 597
 598         parent_class = class_get(class_dev->class);
 599         if (!parent_class)
 600                 goto out1;
 601
 602         parent_class_dev = class_device_get(class_dev->parent);
 603
 604         pr_debug("CLASS: registering class device: ID = '%s'\n",
 605                  class_dev->class_id);
 606
 607         /* first, register with generic layer. */
 608         error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
 609         if (error)
 610                 goto out2;
 611
 612         if (parent_class_dev)
 613                 class_dev->kobj.parent = &parent_class_dev->kobj;
 614         else
 615                 class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
 616
 617         error = kobject_add(&class_dev->kobj);
 618         if (error)
 619                 goto out2;
 620
 621         /* add the needed attributes to this device */
 622         error = sysfs_create_link(&class_dev->kobj,
 623                                   &parent_class->subsys.kset.kobj, "subsystem");
 624         if (error)
 625                 goto out3;
 626         class_dev->uevent_attr.attr.name = "uevent";
 627         class_dev->uevent_attr.attr.mode = S_IWUSR;
 628         class_dev->uevent_attr.attr.owner = parent_class->owner;
 629         class_dev->uevent_attr.store = store_uevent;
 630         error = class_device_create_file(class_dev, &class_dev->uevent_attr);
 631         if (error)
 632                 goto out3;
 633
 634         if (MAJOR(class_dev->devt)) {
 635                 struct class_device_attribute *attr;
 636                 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
 637                 if (!attr) {
 638                         error = -ENOMEM;
 639                         goto out4;
 640                 }
 641                 attr->attr.name = "dev";
 642                 attr->attr.mode = S_IRUGO;
 643                 attr->attr.owner = parent_class->owner;
 644                 attr->show = show_dev;
 645                 error = class_device_create_file(class_dev, attr);
 646                 if (error) {
 647                         kfree(attr);
 648                         goto out4;
 649                 }
 650
 651                 class_dev->devt_attr = attr;
 652         }
 653
 654         error = class_device_add_attrs(class_dev);
 655         if (error)
 656                 goto out5;
 657
 658         if (class_dev->dev) {
 659                 error = sysfs_create_link(&class_dev->kobj,
 660                                           &class_dev->dev->kobj, "device");
 661                 if (error)
 662                         goto out6;
 663         }
 664
 665         error = class_device_add_groups(class_dev);
 666         if (error)
 667                 goto out7;
 668
 669         error = make_deprecated_class_device_links(class_dev);
 670         if (error)
 671                 goto out8;
 672
 673         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
 674
 675         /* notify any interfaces this device is now here */
 676         down(&parent_class->sem);
 677         list_add_tail(&class_dev->node, &parent_class->children);
 678         list_for_each_entry(class_intf, &parent_class->interfaces, node) {
 679                 if (class_intf->add)
 680                         class_intf->add(class_dev, class_intf);
 681         }
 682         up(&parent_class->sem);
 683
 684         goto out1;
 685
 686  out8:
 687         class_device_remove_groups(class_dev);
 688  out7:
 689         if (class_dev->dev)
 690                 sysfs_remove_link(&class_dev->kobj, "device");
 691  out6:
 692         class_device_remove_attrs(class_dev);
 693  out5:
 694         if (class_dev->devt_attr)
 695                 class_device_remove_file(class_dev, class_dev->devt_attr);
 696  out4:
 697         class_device_remove_file(class_dev, &class_dev->uevent_attr);
 698  out3:
 699         kobject_del(&class_dev->kobj);
 700  out2:
 701         if(parent_class_dev)
 702                 class_device_put(parent_class_dev);
 703         class_put(parent_class);
 704  out1:
 705         class_device_put(class_dev);
 706         return error;
 707 }
 708
 709 int class_device_register(struct class_device *class_dev)
 710 {
 711         class_device_initialize(class_dev);
 712         return class_device_add(class_dev);
 713 }
 714
 715 /**
 716  * class_device_create - creates a class device and registers it with sysfs
 717  * @cls: pointer to the struct class that this device should be registered to.
 718  * @parent: pointer to the parent struct class_device of this new device, if any.
 719  * @devt: the dev_t for the char device to be added.
 720  * @device: a pointer to a struct device that is assiociated with this class device.
 721  * @fmt: string for the class device's name
 722  *
 723  * This function can be used by char device classes.  A struct
 724  * class_device will be created in sysfs, registered to the specified
 725  * class.
 726  * A "dev" file will be created, showing the dev_t for the device, if
 727  * the dev_t is not 0,0.
 728  * If a pointer to a parent struct class_device is passed in, the newly
 729  * created struct class_device will be a child of that device in sysfs.
 730  * The pointer to the struct class_device will be returned from the
 731  * call.  Any further sysfs files that might be required can be created
 732  * using this pointer.
 733  *
 734  * Note: the struct class passed to this function must have previously
 735  * been created with a call to class_create().
 736  */
 737 struct class_device *class_device_create(struct class *cls,
 738                                          struct class_device *parent,
 739                                          dev_t devt,
 740                                          struct device *device,
 741                                          const char *fmt, ...)
 742 {
 743         va_list args;
 744         struct class_device *class_dev = NULL;
 745         int retval = -ENODEV;
 746
 747         if (cls == NULL || IS_ERR(cls))
 748                 goto error;
 749
 750         class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
 751         if (!class_dev) {
 752                 retval = -ENOMEM;
 753                 goto error;
 754         }
 755
 756         class_dev->devt = devt;
 757         class_dev->dev = device;
 758         class_dev->class = cls;
 759         class_dev->parent = parent;
 760         class_dev->release = class_device_create_release;
 761         class_dev->uevent = class_device_create_uevent;
 762
 763         va_start(args, fmt);
 764         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
 765         va_end(args);
 766         retval = class_device_register(class_dev);
 767         if (retval)
 768                 goto error;
 769
 770         return class_dev;
 771
 772 error:
 773         kfree(class_dev);
 774         return ERR_PTR(retval);
 775 }
 776
 777 void class_device_del(struct class_device *class_dev)
 778 {
 779         struct class *parent_class = class_dev->class;
 780         struct class_device *parent_device = class_dev->parent;
 781         struct class_interface *class_intf;
 782
 783         if (parent_class) {
 784                 down(&parent_class->sem);
 785                 list_del_init(&class_dev->node);
 786                 list_for_each_entry(class_intf, &parent_class->interfaces, node)
 787                         if (class_intf->remove)
 788                                 class_intf->remove(class_dev, class_intf);
 789                 up(&parent_class->sem);
 790         }
 791
 792         if (class_dev->dev) {
 793                 remove_deprecated_class_device_links(class_dev);
 794                 sysfs_remove_link(&class_dev->kobj, "device");
 795         }
 796         sysfs_remove_link(&class_dev->kobj, "subsystem");
 797         class_device_remove_file(class_dev, &class_dev->uevent_attr);
 798         if (class_dev->devt_attr)
 799                 class_device_remove_file(class_dev, class_dev->devt_attr);
 800         class_device_remove_attrs(class_dev);
 801         class_device_remove_groups(class_dev);
 802
 803         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
 804         kobject_del(&class_dev->kobj);
 805
 806         class_device_put(parent_device);
 807         class_put(parent_class);
 808 }
 809
 810 void class_device_unregister(struct class_device *class_dev)
 811 {
 812         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 813                  class_dev->class_id);
 814         class_device_del(class_dev);
 815         class_device_put(class_dev);
 816 }
 817
 818 /**
 819  * class_device_destroy - removes a class device that was created with class_device_create()
 820  * @cls: the pointer to the struct class that this device was registered * with.
 821  * @devt: the dev_t of the device that was previously registered.
 822  *
 823  * This call unregisters and cleans up a class device that was created with a
 824  * call to class_device_create()
 825  */
 826 void class_device_destroy(struct class *cls, dev_t devt)
 827 {
 828         struct class_device *class_dev = NULL;
 829         struct class_device *class_dev_tmp;
 830
 831         down(&cls->sem);
 832         list_for_each_entry(class_dev_tmp, &cls->children, node) {
 833                 if (class_dev_tmp->devt == devt) {
 834                         class_dev = class_dev_tmp;
 835                         break;
 836                 }
 837         }
 838         up(&cls->sem);
 839
 840         if (class_dev)
 841                 class_device_unregister(class_dev);
 842 }
 843
 844 int class_device_rename(struct class_device *class_dev, char *new_name)
 845 {
 846         int error = 0;
 847         char *old_class_name = NULL, *new_class_name = NULL;
 848
 849         class_dev = class_device_get(class_dev);
 850         if (!class_dev)
 851                 return -EINVAL;
 852
 853         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
 854                  new_name);
 855
 856 #ifdef CONFIG_SYSFS_DEPRECATED
 857         if (class_dev->dev)
 858                 old_class_name = make_class_name(class_dev->class->name,
 859                                                  &class_dev->kobj);
 860 #endif
 861
 862         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
 863
 864         error = kobject_rename(&class_dev->kobj, new_name);
 865
 866 #ifdef CONFIG_SYSFS_DEPRECATED
 867         if (class_dev->dev) {
 868                 new_class_name = make_class_name(class_dev->class->name,
 869                                                  &class_dev->kobj);
 870                 if (new_class_name)
 871                         sysfs_create_link(&class_dev->dev->kobj,
 872                                           &class_dev->kobj, new_class_name);
 873                 if (old_class_name)
 874                         sysfs_remove_link(&class_dev->dev->kobj,
 875                                                 old_class_name);
 876         }
 877 #endif
 878         class_device_put(class_dev);
 879
 880         kfree(old_class_name);
 881         kfree(new_class_name);
 882
 883         return error;
 884 }
 885
 886 struct class_device * class_device_get(struct class_device *class_dev)
 887 {
 888         if (class_dev)
 889                 return to_class_dev(kobject_get(&class_dev->kobj));
 890         return NULL;
 891 }
 892
 893 void class_device_put(struct class_device *class_dev)
 894 {
 895         if (class_dev)
 896                 kobject_put(&class_dev->kobj);
 897 }
 898
 899
 900 int class_interface_register(struct class_interface *class_intf)
 901 {
 902         struct class *parent;
 903         struct class_device *class_dev;
 904         struct device *dev;
 905
 906         if (!class_intf || !class_intf->class)
 907                 return -ENODEV;
 908
 909         parent = class_get(class_intf->class);
 910         if (!parent)
 911                 return -EINVAL;
 912
 913         down(&parent->sem);
 914         list_add_tail(&class_intf->node, &parent->interfaces);
 915         if (class_intf->add) {
 916                 list_for_each_entry(class_dev, &parent->children, node)
 917                         class_intf->add(class_dev, class_intf);
 918         }
 919         if (class_intf->add_dev) {
 920                 list_for_each_entry(dev, &parent->devices, node)
 921                         class_intf->add_dev(dev, class_intf);
 922         }
 923         up(&parent->sem);
 924
 925         return 0;
 926 }
 927
 928 void class_interface_unregister(struct class_interface *class_intf)
 929 {
 930         struct class * parent = class_intf->class;
 931         struct class_device *class_dev;
 932         struct device *dev;
 933
 934         if (!parent)
 935                 return;
 936
 937         down(&parent->sem);
 938         list_del_init(&class_intf->node);
 939         if (class_intf->remove) {
 940                 list_for_each_entry(class_dev, &parent->children, node)
 941                         class_intf->remove(class_dev, class_intf);
 942         }
 943         if (class_intf->remove_dev) {
 944                 list_for_each_entry(dev, &parent->devices, node)
 945                         class_intf->remove_dev(dev, class_intf);
 946         }
 947         up(&parent->sem);
 948
 949         class_put(parent);
 950 }
 951
 952 int __init classes_init(void)
 953 {
 954         int retval;
 955
 956         retval = subsystem_register(&class_subsys);
 957         if (retval)
 958                 return retval;
 959
 960         /* ick, this is ugly, the things we go through to keep from showing up
 961          * in sysfs... */
 962         subsystem_init(&class_obj_subsys);
 963         if (!class_obj_subsys.kset.subsys)
 964                         class_obj_subsys.kset.subsys = &class_obj_subsys;
 965         return 0;
 966 }
 967
 968 EXPORT_SYMBOL_GPL(class_create_file);
 969 EXPORT_SYMBOL_GPL(class_remove_file);
 970 EXPORT_SYMBOL_GPL(class_register);
 971 EXPORT_SYMBOL_GPL(class_unregister);
 972 EXPORT_SYMBOL_GPL(class_create);
 973 EXPORT_SYMBOL_GPL(class_destroy);
 974
 975 EXPORT_SYMBOL_GPL(class_device_register);
 976 EXPORT_SYMBOL_GPL(class_device_unregister);
 977 EXPORT_SYMBOL_GPL(class_device_initialize);
 978 EXPORT_SYMBOL_GPL(class_device_add);
 979 EXPORT_SYMBOL_GPL(class_device_del);
 980 EXPORT_SYMBOL_GPL(class_device_get);
 981 EXPORT_SYMBOL_GPL(class_device_put);
 982 EXPORT_SYMBOL_GPL(class_device_create);
 983 EXPORT_SYMBOL_GPL(class_device_destroy);
 984 EXPORT_SYMBOL_GPL(class_device_create_file);
 985 EXPORT_SYMBOL_GPL(class_device_remove_file);
 986 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
 987 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
 988
 989 EXPORT_SYMBOL_GPL(class_interface_register);
 990 EXPORT_SYMBOL_GPL(class_interface_unregister);