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