[CLASS DEVICE]: add attribute_group creation
[linux-2.6.git] / 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/config.h>
14 #include <linux/device.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/string.h>
18 #include <linux/kdev_t.h>
19 #include <linux/err.h>
20 #include <linux/slab.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.kset.kobj)
25
26 static ssize_t
27 class_attr_show(struct kobject * kobj, struct attribute * attr, 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
39 class_attr_store(struct kobject * kobj, struct attribute * attr,
40                  const char * buf, size_t count)
41 {
42         struct class_attribute * class_attr = to_class_attr(attr);
43         struct class * dc = to_class(kobj);
44         ssize_t ret = -EIO;
45
46         if (class_attr->store)
47                 ret = class_attr->store(dc, buf, count);
48         return ret;
49 }
50
51 static void class_release(struct kobject * kobj)
52 {
53         struct class *class = to_class(kobj);
54
55         pr_debug("class '%s': release.\n", class->name);
56
57         if (class->class_release)
58                 class->class_release(class);
59         else
60                 pr_debug("class '%s' does not have a release() function, "
61                          "be careful\n", class->name);
62 }
63
64 static struct sysfs_ops class_sysfs_ops = {
65         .show   = class_attr_show,
66         .store  = class_attr_store,
67 };
68
69 static struct kobj_type ktype_class = {
70         .sysfs_ops      = &class_sysfs_ops,
71         .release        = class_release,
72 };
73
74 /* Hotplug events for classes go to the class_obj subsys */
75 static decl_subsys(class, &ktype_class, NULL);
76
77
78 int class_create_file(struct class * cls, const struct class_attribute * attr)
79 {
80         int error;
81         if (cls) {
82                 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
83         } else
84                 error = -EINVAL;
85         return error;
86 }
87
88 void class_remove_file(struct class * cls, const struct class_attribute * attr)
89 {
90         if (cls)
91                 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
92 }
93
94 struct class * class_get(struct class * cls)
95 {
96         if (cls)
97                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
98         return NULL;
99 }
100
101 void class_put(struct class * cls)
102 {
103         if (cls)
104                 subsys_put(&cls->subsys);
105 }
106
107
108 static int add_class_attrs(struct class * cls)
109 {
110         int i;
111         int error = 0;
112
113         if (cls->class_attrs) {
114                 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
115                         error = class_create_file(cls,&cls->class_attrs[i]);
116                         if (error)
117                                 goto Err;
118                 }
119         }
120  Done:
121         return error;
122  Err:
123         while (--i >= 0)
124                 class_remove_file(cls,&cls->class_attrs[i]);
125         goto Done;
126 }
127
128 static void remove_class_attrs(struct class * cls)
129 {
130         int i;
131
132         if (cls->class_attrs) {
133                 for (i = 0; attr_name(cls->class_attrs[i]); i++)
134                         class_remove_file(cls,&cls->class_attrs[i]);
135         }
136 }
137
138 int class_register(struct class * cls)
139 {
140         int error;
141
142         pr_debug("device class '%s': registering\n", cls->name);
143
144         INIT_LIST_HEAD(&cls->children);
145         INIT_LIST_HEAD(&cls->interfaces);
146         init_MUTEX(&cls->sem);
147         error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
148         if (error)
149                 return error;
150
151         subsys_set_kset(cls, class_subsys);
152
153         error = subsystem_register(&cls->subsys);
154         if (!error) {
155                 error = add_class_attrs(class_get(cls));
156                 class_put(cls);
157         }
158         return error;
159 }
160
161 void class_unregister(struct class * cls)
162 {
163         pr_debug("device class '%s': unregistering\n", cls->name);
164         remove_class_attrs(cls);
165         subsystem_unregister(&cls->subsys);
166 }
167
168 static void class_create_release(struct class *cls)
169 {
170         pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
171         kfree(cls);
172 }
173
174 static void class_device_create_release(struct class_device *class_dev)
175 {
176         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
177         kfree(class_dev);
178 }
179
180 /* needed to allow these devices to have parent class devices */
181 static int class_device_create_uevent(struct class_device *class_dev,
182                                        char **envp, int num_envp,
183                                        char *buffer, int buffer_size)
184 {
185         pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
186         return 0;
187 }
188
189 /**
190  * class_create - create a struct class structure
191  * @owner: pointer to the module that is to "own" this struct class
192  * @name: pointer to a string for the name of this class.
193  *
194  * This is used to create a struct class pointer that can then be used
195  * in calls to class_device_create().
196  *
197  * Note, the pointer created here is to be destroyed when finished by
198  * making a call to class_destroy().
199  */
200 struct class *class_create(struct module *owner, char *name)
201 {
202         struct class *cls;
203         int retval;
204
205         cls = kzalloc(sizeof(*cls), GFP_KERNEL);
206         if (!cls) {
207                 retval = -ENOMEM;
208                 goto error;
209         }
210
211         cls->name = name;
212         cls->owner = owner;
213         cls->class_release = class_create_release;
214         cls->release = class_device_create_release;
215
216         retval = class_register(cls);
217         if (retval)
218                 goto error;
219
220         return cls;
221
222 error:
223         kfree(cls);
224         return ERR_PTR(retval);
225 }
226
227 /**
228  * class_destroy - destroys a struct class structure
229  * @cs: pointer to the struct class that is to be destroyed
230  *
231  * Note, the pointer to be destroyed must have been created with a call
232  * to class_create().
233  */
234 void class_destroy(struct class *cls)
235 {
236         if ((cls == NULL) || (IS_ERR(cls)))
237                 return;
238
239         class_unregister(cls);
240 }
241
242 /* Class Device Stuff */
243
244 int class_device_create_file(struct class_device * class_dev,
245                              const struct class_device_attribute * attr)
246 {
247         int error = -EINVAL;
248         if (class_dev)
249                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
250         return error;
251 }
252
253 void class_device_remove_file(struct class_device * class_dev,
254                               const struct class_device_attribute * attr)
255 {
256         if (class_dev)
257                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
258 }
259
260 int class_device_create_bin_file(struct class_device *class_dev,
261                                  struct bin_attribute *attr)
262 {
263         int error = -EINVAL;
264         if (class_dev)
265                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
266         return error;
267 }
268
269 void class_device_remove_bin_file(struct class_device *class_dev,
270                                   struct bin_attribute *attr)
271 {
272         if (class_dev)
273                 sysfs_remove_bin_file(&class_dev->kobj, attr);
274 }
275
276 static ssize_t
277 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
278                        char * buf)
279 {
280         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
281         struct class_device * cd = to_class_dev(kobj);
282         ssize_t ret = 0;
283
284         if (class_dev_attr->show)
285                 ret = class_dev_attr->show(cd, buf);
286         return ret;
287 }
288
289 static ssize_t
290 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
291                         const char * buf, size_t count)
292 {
293         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
294         struct class_device * cd = to_class_dev(kobj);
295         ssize_t ret = 0;
296
297         if (class_dev_attr->store)
298                 ret = class_dev_attr->store(cd, buf, count);
299         return ret;
300 }
301
302 static struct sysfs_ops class_dev_sysfs_ops = {
303         .show   = class_device_attr_show,
304         .store  = class_device_attr_store,
305 };
306
307 static void class_dev_release(struct kobject * kobj)
308 {
309         struct class_device *cd = to_class_dev(kobj);
310         struct class * cls = cd->class;
311
312         pr_debug("device class '%s': release.\n", cd->class_id);
313
314         kfree(cd->devt_attr);
315         cd->devt_attr = NULL;
316
317         if (cd->release)
318                 cd->release(cd);
319         else if (cls->release)
320                 cls->release(cd);
321         else {
322                 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
323                         "it is broken and must be fixed.\n",
324                         cd->class_id);
325                 WARN_ON(1);
326         }
327 }
328
329 static struct kobj_type ktype_class_device = {
330         .sysfs_ops      = &class_dev_sysfs_ops,
331         .release        = class_dev_release,
332 };
333
334 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
335 {
336         struct kobj_type *ktype = get_ktype(kobj);
337
338         if (ktype == &ktype_class_device) {
339                 struct class_device *class_dev = to_class_dev(kobj);
340                 if (class_dev->class)
341                         return 1;
342         }
343         return 0;
344 }
345
346 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
347 {
348         struct class_device *class_dev = to_class_dev(kobj);
349
350         return class_dev->class->name;
351 }
352
353 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
354                          int num_envp, char *buffer, int buffer_size)
355 {
356         struct class_device *class_dev = to_class_dev(kobj);
357         int i = 0;
358         int length = 0;
359         int retval = 0;
360
361         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
362
363         if (class_dev->dev) {
364                 /* add physical device, backing this device  */
365                 struct device *dev = class_dev->dev;
366                 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
367
368                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
369                                &length, "PHYSDEVPATH=%s", path);
370                 kfree(path);
371
372                 if (dev->bus)
373                         add_uevent_var(envp, num_envp, &i,
374                                        buffer, buffer_size, &length,
375                                        "PHYSDEVBUS=%s", dev->bus->name);
376
377                 if (dev->driver)
378                         add_uevent_var(envp, num_envp, &i,
379                                        buffer, buffer_size, &length,
380                                        "PHYSDEVDRIVER=%s", dev->driver->name);
381         }
382
383         if (MAJOR(class_dev->devt)) {
384                 add_uevent_var(envp, num_envp, &i,
385                                buffer, buffer_size, &length,
386                                "MAJOR=%u", MAJOR(class_dev->devt));
387
388                 add_uevent_var(envp, num_envp, &i,
389                                buffer, buffer_size, &length,
390                                "MINOR=%u", MINOR(class_dev->devt));
391         }
392
393         /* terminate, set to next free slot, shrink available space */
394         envp[i] = NULL;
395         envp = &envp[i];
396         num_envp -= i;
397         buffer = &buffer[length];
398         buffer_size -= length;
399
400         if (class_dev->uevent) {
401                 /* have the class device specific function add its stuff */
402                 retval = class_dev->uevent(class_dev, envp, num_envp,
403                                             buffer, buffer_size);
404                 if (retval)
405                         pr_debug("class_dev->uevent() returned %d\n", retval);
406         } else if (class_dev->class->uevent) {
407                 /* have the class specific function add its stuff */
408                 retval = class_dev->class->uevent(class_dev, envp, num_envp,
409                                                    buffer, buffer_size);
410                 if (retval)
411                         pr_debug("class->uevent() returned %d\n", retval);
412         }
413
414         return retval;
415 }
416
417 static struct kset_uevent_ops class_uevent_ops = {
418         .filter =       class_uevent_filter,
419         .name =         class_uevent_name,
420         .uevent =       class_uevent,
421 };
422
423 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
424
425
426 static int class_device_add_attrs(struct class_device * cd)
427 {
428         int i;
429         int error = 0;
430         struct class * cls = cd->class;
431
432         if (cls->class_dev_attrs) {
433                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
434                         error = class_device_create_file(cd,
435                                                          &cls->class_dev_attrs[i]);
436                         if (error)
437                                 goto Err;
438                 }
439         }
440  Done:
441         return error;
442  Err:
443         while (--i >= 0)
444                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
445         goto Done;
446 }
447
448 static void class_device_remove_attrs(struct class_device * cd)
449 {
450         int i;
451         struct class * cls = cd->class;
452
453         if (cls->class_dev_attrs) {
454                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
455                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
456         }
457 }
458
459 static int class_device_add_groups(struct class_device * cd)
460 {
461         int i;
462         int error = 0;
463
464         if (cd->groups) {
465                 for (i = 0; cd->groups[i]; i++) {
466                         error = sysfs_create_group(&cd->kobj, cd->groups[i]);
467                         if (error) {
468                                 while (--i >= 0)
469                                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
470                                 goto out;
471                         }
472                 }
473         }
474 out:
475         return error;
476 }
477
478 static void class_device_remove_groups(struct class_device * cd)
479 {
480         int i;
481         if (cd->groups) {
482                 for (i = 0; cd->groups[i]; i++) {
483                         sysfs_remove_group(&cd->kobj, cd->groups[i]);
484                 }
485         }
486 }
487
488 static ssize_t show_dev(struct class_device *class_dev, char *buf)
489 {
490         return print_dev_t(buf, class_dev->devt);
491 }
492
493 static ssize_t store_uevent(struct class_device *class_dev,
494                             const char *buf, size_t count)
495 {
496         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
497         return count;
498 }
499
500 void class_device_initialize(struct class_device *class_dev)
501 {
502         kobj_set_kset_s(class_dev, class_obj_subsys);
503         kobject_init(&class_dev->kobj);
504         INIT_LIST_HEAD(&class_dev->node);
505 }
506
507 static char *make_class_name(struct class_device *class_dev)
508 {
509         char *name;
510         int size;
511
512         size = strlen(class_dev->class->name) +
513                 strlen(kobject_name(&class_dev->kobj)) + 2;
514
515         name = kmalloc(size, GFP_KERNEL);
516         if (!name)
517                 return ERR_PTR(-ENOMEM);
518
519         strcpy(name, class_dev->class->name);
520         strcat(name, ":");
521         strcat(name, kobject_name(&class_dev->kobj));
522         return name;
523 }
524
525 int class_device_add(struct class_device *class_dev)
526 {
527         struct class *parent_class = NULL;
528         struct class_device *parent_class_dev = NULL;
529         struct class_interface *class_intf;
530         char *class_name = NULL;
531         int error = -EINVAL;
532
533         class_dev = class_device_get(class_dev);
534         if (!class_dev)
535                 return -EINVAL;
536
537         if (!strlen(class_dev->class_id))
538                 goto register_done;
539
540         parent_class = class_get(class_dev->class);
541         if (!parent_class)
542                 goto register_done;
543         parent_class_dev = class_device_get(class_dev->parent);
544
545         pr_debug("CLASS: registering class device: ID = '%s'\n",
546                  class_dev->class_id);
547
548         /* first, register with generic layer. */
549         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
550         if (parent_class_dev)
551                 class_dev->kobj.parent = &parent_class_dev->kobj;
552         else
553                 class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
554
555         error = kobject_add(&class_dev->kobj);
556         if (error)
557                 goto register_done;
558
559         /* add the needed attributes to this device */
560         class_dev->uevent_attr.attr.name = "uevent";
561         class_dev->uevent_attr.attr.mode = S_IWUSR;
562         class_dev->uevent_attr.attr.owner = parent_class->owner;
563         class_dev->uevent_attr.store = store_uevent;
564         class_device_create_file(class_dev, &class_dev->uevent_attr);
565
566         if (MAJOR(class_dev->devt)) {
567                 struct class_device_attribute *attr;
568                 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
569                 if (!attr) {
570                         error = -ENOMEM;
571                         kobject_del(&class_dev->kobj);
572                         goto register_done;
573                 }
574                 attr->attr.name = "dev";
575                 attr->attr.mode = S_IRUGO;
576                 attr->attr.owner = parent_class->owner;
577                 attr->show = show_dev;
578                 class_device_create_file(class_dev, attr);
579                 class_dev->devt_attr = attr;
580         }
581
582         class_device_add_attrs(class_dev);
583         if (class_dev->dev) {
584                 class_name = make_class_name(class_dev);
585                 sysfs_create_link(&class_dev->kobj,
586                                   &class_dev->dev->kobj, "device");
587                 sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
588                                   class_name);
589         }
590
591         class_device_add_groups(class_dev);
592
593         kobject_uevent(&class_dev->kobj, KOBJ_ADD);
594
595         /* notify any interfaces this device is now here */
596         down(&parent_class->sem);
597         list_add_tail(&class_dev->node, &parent_class->children);
598         list_for_each_entry(class_intf, &parent_class->interfaces, node) {
599                 if (class_intf->add)
600                         class_intf->add(class_dev, class_intf);
601         }
602         up(&parent_class->sem);
603
604  register_done:
605         if (error) {
606                 class_put(parent_class);
607                 class_device_put(parent_class_dev);
608         }
609         class_device_put(class_dev);
610         kfree(class_name);
611         return error;
612 }
613
614 int class_device_register(struct class_device *class_dev)
615 {
616         class_device_initialize(class_dev);
617         return class_device_add(class_dev);
618 }
619
620 /**
621  * class_device_create - creates a class device and registers it with sysfs
622  * @cs: pointer to the struct class that this device should be registered to.
623  * @parent: pointer to the parent struct class_device of this new device, if any.
624  * @dev: the dev_t for the char device to be added.
625  * @device: a pointer to a struct device that is assiociated with this class device.
626  * @fmt: string for the class device's name
627  *
628  * This function can be used by char device classes.  A struct
629  * class_device will be created in sysfs, registered to the specified
630  * class.
631  * A "dev" file will be created, showing the dev_t for the device, if
632  * the dev_t is not 0,0.
633  * If a pointer to a parent struct class_device is passed in, the newly
634  * created struct class_device will be a child of that device in sysfs.
635  * The pointer to the struct class_device will be returned from the
636  * call.  Any further sysfs files that might be required can be created
637  * using this pointer.
638  *
639  * Note: the struct class passed to this function must have previously
640  * been created with a call to class_create().
641  */
642 struct class_device *class_device_create(struct class *cls,
643                                          struct class_device *parent,
644                                          dev_t devt,
645                                          struct device *device, char *fmt, ...)
646 {
647         va_list args;
648         struct class_device *class_dev = NULL;
649         int retval = -ENODEV;
650
651         if (cls == NULL || IS_ERR(cls))
652                 goto error;
653
654         class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
655         if (!class_dev) {
656                 retval = -ENOMEM;
657                 goto error;
658         }
659
660         class_dev->devt = devt;
661         class_dev->dev = device;
662         class_dev->class = cls;
663         class_dev->parent = parent;
664         class_dev->release = class_device_create_release;
665         class_dev->uevent = class_device_create_uevent;
666
667         va_start(args, fmt);
668         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
669         va_end(args);
670         retval = class_device_register(class_dev);
671         if (retval)
672                 goto error;
673
674         return class_dev;
675
676 error:
677         kfree(class_dev);
678         return ERR_PTR(retval);
679 }
680
681 void class_device_del(struct class_device *class_dev)
682 {
683         struct class *parent_class = class_dev->class;
684         struct class_device *parent_device = class_dev->parent;
685         struct class_interface *class_intf;
686         char *class_name = NULL;
687
688         if (parent_class) {
689                 down(&parent_class->sem);
690                 list_del_init(&class_dev->node);
691                 list_for_each_entry(class_intf, &parent_class->interfaces, node)
692                         if (class_intf->remove)
693                                 class_intf->remove(class_dev, class_intf);
694                 up(&parent_class->sem);
695         }
696
697         if (class_dev->dev) {
698                 class_name = make_class_name(class_dev);
699                 sysfs_remove_link(&class_dev->kobj, "device");
700                 sysfs_remove_link(&class_dev->dev->kobj, class_name);
701         }
702         class_device_remove_file(class_dev, &class_dev->uevent_attr);
703         if (class_dev->devt_attr)
704                 class_device_remove_file(class_dev, class_dev->devt_attr);
705         class_device_remove_attrs(class_dev);
706         class_device_remove_groups(class_dev);
707
708         kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
709         kobject_del(&class_dev->kobj);
710
711         class_device_put(parent_device);
712         class_put(parent_class);
713         kfree(class_name);
714 }
715
716 void class_device_unregister(struct class_device *class_dev)
717 {
718         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
719                  class_dev->class_id);
720         class_device_del(class_dev);
721         class_device_put(class_dev);
722 }
723
724 /**
725  * class_device_destroy - removes a class device that was created with class_device_create()
726  * @cls: the pointer to the struct class that this device was registered * with.
727  * @dev: the dev_t of the device that was previously registered.
728  *
729  * This call unregisters and cleans up a class device that was created with a
730  * call to class_device_create()
731  */
732 void class_device_destroy(struct class *cls, dev_t devt)
733 {
734         struct class_device *class_dev = NULL;
735         struct class_device *class_dev_tmp;
736
737         down(&cls->sem);
738         list_for_each_entry(class_dev_tmp, &cls->children, node) {
739                 if (class_dev_tmp->devt == devt) {
740                         class_dev = class_dev_tmp;
741                         break;
742                 }
743         }
744         up(&cls->sem);
745
746         if (class_dev)
747                 class_device_unregister(class_dev);
748 }
749
750 int class_device_rename(struct class_device *class_dev, char *new_name)
751 {
752         int error = 0;
753         char *old_class_name = NULL, *new_class_name = NULL;
754
755         class_dev = class_device_get(class_dev);
756         if (!class_dev)
757                 return -EINVAL;
758
759         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
760                  new_name);
761
762         if (class_dev->dev)
763                 old_class_name = make_class_name(class_dev);
764
765         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
766
767         error = kobject_rename(&class_dev->kobj, new_name);
768
769         if (class_dev->dev) {
770                 new_class_name = make_class_name(class_dev);
771                 sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
772                                   new_class_name);
773                 sysfs_remove_link(&class_dev->dev->kobj, old_class_name);
774         }
775         class_device_put(class_dev);
776
777         kfree(old_class_name);
778         kfree(new_class_name);
779
780         return error;
781 }
782
783 struct class_device * class_device_get(struct class_device *class_dev)
784 {
785         if (class_dev)
786                 return to_class_dev(kobject_get(&class_dev->kobj));
787         return NULL;
788 }
789
790 void class_device_put(struct class_device *class_dev)
791 {
792         if (class_dev)
793                 kobject_put(&class_dev->kobj);
794 }
795
796
797 int class_interface_register(struct class_interface *class_intf)
798 {
799         struct class *parent;
800         struct class_device *class_dev;
801
802         if (!class_intf || !class_intf->class)
803                 return -ENODEV;
804
805         parent = class_get(class_intf->class);
806         if (!parent)
807                 return -EINVAL;
808
809         down(&parent->sem);
810         list_add_tail(&class_intf->node, &parent->interfaces);
811         if (class_intf->add) {
812                 list_for_each_entry(class_dev, &parent->children, node)
813                         class_intf->add(class_dev, class_intf);
814         }
815         up(&parent->sem);
816
817         return 0;
818 }
819
820 void class_interface_unregister(struct class_interface *class_intf)
821 {
822         struct class * parent = class_intf->class;
823         struct class_device *class_dev;
824
825         if (!parent)
826                 return;
827
828         down(&parent->sem);
829         list_del_init(&class_intf->node);
830         if (class_intf->remove) {
831                 list_for_each_entry(class_dev, &parent->children, node)
832                         class_intf->remove(class_dev, class_intf);
833         }
834         up(&parent->sem);
835
836         class_put(parent);
837 }
838
839
840
841 int __init classes_init(void)
842 {
843         int retval;
844
845         retval = subsystem_register(&class_subsys);
846         if (retval)
847                 return retval;
848
849         /* ick, this is ugly, the things we go through to keep from showing up
850          * in sysfs... */
851         subsystem_init(&class_obj_subsys);
852         if (!class_obj_subsys.kset.subsys)
853                         class_obj_subsys.kset.subsys = &class_obj_subsys;
854         return 0;
855 }
856
857 EXPORT_SYMBOL_GPL(class_create_file);
858 EXPORT_SYMBOL_GPL(class_remove_file);
859 EXPORT_SYMBOL_GPL(class_register);
860 EXPORT_SYMBOL_GPL(class_unregister);
861 EXPORT_SYMBOL_GPL(class_get);
862 EXPORT_SYMBOL_GPL(class_put);
863 EXPORT_SYMBOL_GPL(class_create);
864 EXPORT_SYMBOL_GPL(class_destroy);
865
866 EXPORT_SYMBOL_GPL(class_device_register);
867 EXPORT_SYMBOL_GPL(class_device_unregister);
868 EXPORT_SYMBOL_GPL(class_device_initialize);
869 EXPORT_SYMBOL_GPL(class_device_add);
870 EXPORT_SYMBOL_GPL(class_device_del);
871 EXPORT_SYMBOL_GPL(class_device_get);
872 EXPORT_SYMBOL_GPL(class_device_put);
873 EXPORT_SYMBOL_GPL(class_device_create);
874 EXPORT_SYMBOL_GPL(class_device_destroy);
875 EXPORT_SYMBOL_GPL(class_device_create_file);
876 EXPORT_SYMBOL_GPL(class_device_remove_file);
877 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
878 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
879
880 EXPORT_SYMBOL_GPL(class_interface_register);
881 EXPORT_SYMBOL_GPL(class_interface_unregister);