xref: /openbmc/linux/drivers/base/class.c (revision c21b37f6)
1 /*
2  * class.c - basic device class management
3  *
4  * Copyright (c) 2002-3 Patrick Mochel
5  * Copyright (c) 2002-3 Open Source Development Labs
6  * Copyright (c) 2003-2004 Greg Kroah-Hartman
7  * Copyright (c) 2003-2004 IBM Corp.
8  *
9  * This file is released under the GPLv2
10  *
11  */
12 
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/string.h>
17 #include <linux/kdev_t.h>
18 #include <linux/err.h>
19 #include <linux/slab.h>
20 #include "base.h"
21 
22 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
23 #define to_class(obj) container_of(obj, struct class, subsys.kobj)
24 
25 static ssize_t
26 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
27 {
28 	struct class_attribute * class_attr = to_class_attr(attr);
29 	struct class * dc = to_class(kobj);
30 	ssize_t ret = -EIO;
31 
32 	if (class_attr->show)
33 		ret = class_attr->show(dc, buf);
34 	return ret;
35 }
36 
37 static ssize_t
38 class_attr_store(struct kobject * kobj, struct attribute * attr,
39 		 const char * buf, size_t count)
40 {
41 	struct class_attribute * class_attr = to_class_attr(attr);
42 	struct class * dc = to_class(kobj);
43 	ssize_t ret = -EIO;
44 
45 	if (class_attr->store)
46 		ret = class_attr->store(dc, buf, count);
47 	return ret;
48 }
49 
50 static void class_release(struct kobject * kobj)
51 {
52 	struct class *class = to_class(kobj);
53 
54 	pr_debug("class '%s': release.\n", class->name);
55 
56 	if (class->class_release)
57 		class->class_release(class);
58 	else
59 		pr_debug("class '%s' does not have a release() function, "
60 			 "be careful\n", class->name);
61 }
62 
63 static struct sysfs_ops class_sysfs_ops = {
64 	.show	= class_attr_show,
65 	.store	= class_attr_store,
66 };
67 
68 static struct kobj_type ktype_class = {
69 	.sysfs_ops	= &class_sysfs_ops,
70 	.release	= class_release,
71 };
72 
73 /* Hotplug events for classes go to the class_obj subsys */
74 static decl_subsys(class, &ktype_class, NULL);
75 
76 
77 int class_create_file(struct class * cls, const struct class_attribute * attr)
78 {
79 	int error;
80 	if (cls) {
81 		error = sysfs_create_file(&cls->subsys.kobj, &attr->attr);
82 	} else
83 		error = -EINVAL;
84 	return error;
85 }
86 
87 void class_remove_file(struct class * cls, const struct class_attribute * attr)
88 {
89 	if (cls)
90 		sysfs_remove_file(&cls->subsys.kobj, &attr->attr);
91 }
92 
93 static struct class *class_get(struct class *cls)
94 {
95 	if (cls)
96 		return container_of(subsys_get(&cls->subsys), struct class, subsys);
97 	return NULL;
98 }
99 
100 static void class_put(struct class * cls)
101 {
102 	if (cls)
103 		subsys_put(&cls->subsys);
104 }
105 
106 
107 static int add_class_attrs(struct class * cls)
108 {
109 	int i;
110 	int error = 0;
111 
112 	if (cls->class_attrs) {
113 		for (i = 0; attr_name(cls->class_attrs[i]); i++) {
114 			error = class_create_file(cls,&cls->class_attrs[i]);
115 			if (error)
116 				goto Err;
117 		}
118 	}
119  Done:
120 	return error;
121  Err:
122 	while (--i >= 0)
123 		class_remove_file(cls,&cls->class_attrs[i]);
124 	goto Done;
125 }
126 
127 static void remove_class_attrs(struct class * cls)
128 {
129 	int i;
130 
131 	if (cls->class_attrs) {
132 		for (i = 0; attr_name(cls->class_attrs[i]); i++)
133 			class_remove_file(cls,&cls->class_attrs[i]);
134 	}
135 }
136 
137 int class_register(struct class * cls)
138 {
139 	int error;
140 
141 	pr_debug("device class '%s': registering\n", cls->name);
142 
143 	INIT_LIST_HEAD(&cls->children);
144 	INIT_LIST_HEAD(&cls->devices);
145 	INIT_LIST_HEAD(&cls->interfaces);
146 	kset_init(&cls->class_dirs);
147 	init_MUTEX(&cls->sem);
148 	error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);
149 	if (error)
150 		return error;
151 
152 	subsys_set_kset(cls, class_subsys);
153 
154 	error = subsystem_register(&cls->subsys);
155 	if (!error) {
156 		error = add_class_attrs(class_get(cls));
157 		class_put(cls);
158 	}
159 	return error;
160 }
161 
162 void class_unregister(struct class * cls)
163 {
164 	pr_debug("device class '%s': unregistering\n", cls->name);
165 	remove_class_attrs(cls);
166 	subsystem_unregister(&cls->subsys);
167 }
168 
169 static void class_create_release(struct class *cls)
170 {
171 	pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
172 	kfree(cls);
173 }
174 
175 static void class_device_create_release(struct class_device *class_dev)
176 {
177 	pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
178 	kfree(class_dev);
179 }
180 
181 /* needed to allow these devices to have parent class devices */
182 static int class_device_create_uevent(struct class_device *class_dev,
183 				       char **envp, int num_envp,
184 				       char *buffer, int buffer_size)
185 {
186 	pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
187 	return 0;
188 }
189 
190 /**
191  * class_create - create a struct class structure
192  * @owner: pointer to the module that is to "own" this struct class
193  * @name: pointer to a string for the name of this class.
194  *
195  * This is used to create a struct class pointer that can then be used
196  * in calls to class_device_create().
197  *
198  * Note, the pointer created here is to be destroyed when finished by
199  * making a call to class_destroy().
200  */
201 struct class *class_create(struct module *owner, const char *name)
202 {
203 	struct class *cls;
204 	int retval;
205 
206 	cls = kzalloc(sizeof(*cls), GFP_KERNEL);
207 	if (!cls) {
208 		retval = -ENOMEM;
209 		goto error;
210 	}
211 
212 	cls->name = name;
213 	cls->owner = owner;
214 	cls->class_release = class_create_release;
215 	cls->release = class_device_create_release;
216 
217 	retval = class_register(cls);
218 	if (retval)
219 		goto error;
220 
221 	return cls;
222 
223 error:
224 	kfree(cls);
225 	return ERR_PTR(retval);
226 }
227 
228 /**
229  * class_destroy - destroys a struct class structure
230  * @cls: pointer to the struct class that is to be destroyed
231  *
232  * Note, the pointer to be destroyed must have been created with a call
233  * to class_create().
234  */
235 void class_destroy(struct class *cls)
236 {
237 	if ((cls == NULL) || (IS_ERR(cls)))
238 		return;
239 
240 	class_unregister(cls);
241 }
242 
243 /* Class Device Stuff */
244 
245 int class_device_create_file(struct class_device * class_dev,
246 			     const struct class_device_attribute * attr)
247 {
248 	int error = -EINVAL;
249 	if (class_dev)
250 		error = sysfs_create_file(&class_dev->kobj, &attr->attr);
251 	return error;
252 }
253 
254 void class_device_remove_file(struct class_device * class_dev,
255 			      const struct class_device_attribute * attr)
256 {
257 	if (class_dev)
258 		sysfs_remove_file(&class_dev->kobj, &attr->attr);
259 }
260 
261 int class_device_create_bin_file(struct class_device *class_dev,
262 				 struct bin_attribute *attr)
263 {
264 	int error = -EINVAL;
265 	if (class_dev)
266 		error = sysfs_create_bin_file(&class_dev->kobj, attr);
267 	return error;
268 }
269 
270 void class_device_remove_bin_file(struct class_device *class_dev,
271 				  struct bin_attribute *attr)
272 {
273 	if (class_dev)
274 		sysfs_remove_bin_file(&class_dev->kobj, attr);
275 }
276 
277 static ssize_t
278 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
279 		       char * buf)
280 {
281 	struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
282 	struct class_device * cd = to_class_dev(kobj);
283 	ssize_t ret = 0;
284 
285 	if (class_dev_attr->show)
286 		ret = class_dev_attr->show(cd, buf);
287 	return ret;
288 }
289 
290 static ssize_t
291 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
292 			const char * buf, size_t count)
293 {
294 	struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
295 	struct class_device * cd = to_class_dev(kobj);
296 	ssize_t ret = 0;
297 
298 	if (class_dev_attr->store)
299 		ret = class_dev_attr->store(cd, buf, count);
300 	return ret;
301 }
302 
303 static struct sysfs_ops class_dev_sysfs_ops = {
304 	.show	= class_device_attr_show,
305 	.store	= class_device_attr_store,
306 };
307 
308 static void class_dev_release(struct kobject * kobj)
309 {
310 	struct class_device *cd = to_class_dev(kobj);
311 	struct class * cls = cd->class;
312 
313 	pr_debug("device class '%s': release.\n", cd->class_id);
314 
315 	if (cd->release)
316 		cd->release(cd);
317 	else if (cls->release)
318 		cls->release(cd);
319 	else {
320 		printk(KERN_ERR "Class Device '%s' does not have a release() function, "
321 			"it is broken and must be fixed.\n",
322 			cd->class_id);
323 		WARN_ON(1);
324 	}
325 }
326 
327 static struct kobj_type ktype_class_device = {
328 	.sysfs_ops	= &class_dev_sysfs_ops,
329 	.release	= class_dev_release,
330 };
331 
332 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
333 {
334 	struct kobj_type *ktype = get_ktype(kobj);
335 
336 	if (ktype == &ktype_class_device) {
337 		struct class_device *class_dev = to_class_dev(kobj);
338 		if (class_dev->class)
339 			return 1;
340 	}
341 	return 0;
342 }
343 
344 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
345 {
346 	struct class_device *class_dev = to_class_dev(kobj);
347 
348 	return class_dev->class->name;
349 }
350 
351 #ifdef CONFIG_SYSFS_DEPRECATED
352 char *make_class_name(const char *name, struct kobject *kobj)
353 {
354 	char *class_name;
355 	int size;
356 
357 	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
358 
359 	class_name = kmalloc(size, GFP_KERNEL);
360 	if (!class_name)
361 		return NULL;
362 
363 	strcpy(class_name, name);
364 	strcat(class_name, ":");
365 	strcat(class_name, kobject_name(kobj));
366 	return class_name;
367 }
368 
369 static int make_deprecated_class_device_links(struct class_device *class_dev)
370 {
371 	char *class_name;
372 	int error;
373 
374 	if (!class_dev->dev)
375 		return 0;
376 
377 	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
378 	if (class_name)
379 		error = sysfs_create_link(&class_dev->dev->kobj,
380 					  &class_dev->kobj, class_name);
381 	else
382 		error = -ENOMEM;
383 	kfree(class_name);
384 	return error;
385 }
386 
387 static void remove_deprecated_class_device_links(struct class_device *class_dev)
388 {
389 	char *class_name;
390 
391 	if (!class_dev->dev)
392 		return;
393 
394 	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
395 	if (class_name)
396 		sysfs_remove_link(&class_dev->dev->kobj, class_name);
397 	kfree(class_name);
398 }
399 #else
400 static inline int make_deprecated_class_device_links(struct class_device *cd)
401 { return 0; }
402 static void remove_deprecated_class_device_links(struct class_device *cd)
403 { }
404 #endif
405 
406 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
407 			 int num_envp, char *buffer, int buffer_size)
408 {
409 	struct class_device *class_dev = to_class_dev(kobj);
410 	struct device *dev = class_dev->dev;
411 	int i = 0;
412 	int length = 0;
413 	int retval = 0;
414 
415 	pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
416 
417 	if (MAJOR(class_dev->devt)) {
418 		add_uevent_var(envp, num_envp, &i,
419 			       buffer, buffer_size, &length,
420 			       "MAJOR=%u", MAJOR(class_dev->devt));
421 
422 		add_uevent_var(envp, num_envp, &i,
423 			       buffer, buffer_size, &length,
424 			       "MINOR=%u", MINOR(class_dev->devt));
425 	}
426 
427 	if (dev) {
428 		const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
429 		if (path) {
430 			add_uevent_var(envp, num_envp, &i,
431 				       buffer, buffer_size, &length,
432 				       "PHYSDEVPATH=%s", path);
433 			kfree(path);
434 		}
435 
436 		if (dev->bus)
437 			add_uevent_var(envp, num_envp, &i,
438 				       buffer, buffer_size, &length,
439 				       "PHYSDEVBUS=%s", dev->bus->name);
440 
441 		if (dev->driver)
442 			add_uevent_var(envp, num_envp, &i,
443 				       buffer, buffer_size, &length,
444 				       "PHYSDEVDRIVER=%s", dev->driver->name);
445 	}
446 
447 	/* terminate, set to next free slot, shrink available space */
448 	envp[i] = NULL;
449 	envp = &envp[i];
450 	num_envp -= i;
451 	buffer = &buffer[length];
452 	buffer_size -= length;
453 
454 	if (class_dev->uevent) {
455 		/* have the class device specific function add its stuff */
456 		retval = class_dev->uevent(class_dev, envp, num_envp,
457 					    buffer, buffer_size);
458 		if (retval)
459 			pr_debug("class_dev->uevent() returned %d\n", retval);
460 	} else if (class_dev->class->uevent) {
461 		/* have the class specific function add its stuff */
462 		retval = class_dev->class->uevent(class_dev, envp, num_envp,
463 						   buffer, buffer_size);
464 		if (retval)
465 			pr_debug("class->uevent() returned %d\n", retval);
466 	}
467 
468 	return retval;
469 }
470 
471 static struct kset_uevent_ops class_uevent_ops = {
472 	.filter =	class_uevent_filter,
473 	.name =		class_uevent_name,
474 	.uevent =	class_uevent,
475 };
476 
477 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
478 
479 
480 static int class_device_add_attrs(struct class_device * cd)
481 {
482 	int i;
483 	int error = 0;
484 	struct class * cls = cd->class;
485 
486 	if (cls->class_dev_attrs) {
487 		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
488 			error = class_device_create_file(cd,
489 							 &cls->class_dev_attrs[i]);
490 			if (error)
491 				goto Err;
492 		}
493 	}
494  Done:
495 	return error;
496  Err:
497 	while (--i >= 0)
498 		class_device_remove_file(cd,&cls->class_dev_attrs[i]);
499 	goto Done;
500 }
501 
502 static void class_device_remove_attrs(struct class_device * cd)
503 {
504 	int i;
505 	struct class * cls = cd->class;
506 
507 	if (cls->class_dev_attrs) {
508 		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
509 			class_device_remove_file(cd,&cls->class_dev_attrs[i]);
510 	}
511 }
512 
513 static int class_device_add_groups(struct class_device * cd)
514 {
515 	int i;
516 	int error = 0;
517 
518 	if (cd->groups) {
519 		for (i = 0; cd->groups[i]; i++) {
520 			error = sysfs_create_group(&cd->kobj, cd->groups[i]);
521 			if (error) {
522 				while (--i >= 0)
523 					sysfs_remove_group(&cd->kobj, cd->groups[i]);
524 				goto out;
525 			}
526 		}
527 	}
528 out:
529 	return error;
530 }
531 
532 static void class_device_remove_groups(struct class_device * cd)
533 {
534 	int i;
535 	if (cd->groups) {
536 		for (i = 0; cd->groups[i]; i++) {
537 			sysfs_remove_group(&cd->kobj, cd->groups[i]);
538 		}
539 	}
540 }
541 
542 static ssize_t show_dev(struct class_device *class_dev, char *buf)
543 {
544 	return print_dev_t(buf, class_dev->devt);
545 }
546 
547 static struct class_device_attribute class_devt_attr =
548 	__ATTR(dev, S_IRUGO, show_dev, NULL);
549 
550 static ssize_t store_uevent(struct class_device *class_dev,
551 			    const char *buf, size_t count)
552 {
553 	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
554 	return count;
555 }
556 
557 static struct class_device_attribute class_uevent_attr =
558 	__ATTR(uevent, S_IWUSR, NULL, store_uevent);
559 
560 void class_device_initialize(struct class_device *class_dev)
561 {
562 	kobj_set_kset_s(class_dev, class_obj_subsys);
563 	kobject_init(&class_dev->kobj);
564 	INIT_LIST_HEAD(&class_dev->node);
565 }
566 
567 int class_device_add(struct class_device *class_dev)
568 {
569 	struct class *parent_class = NULL;
570 	struct class_device *parent_class_dev = NULL;
571 	struct class_interface *class_intf;
572 	int error = -EINVAL;
573 
574 	class_dev = class_device_get(class_dev);
575 	if (!class_dev)
576 		return -EINVAL;
577 
578 	if (!strlen(class_dev->class_id))
579 		goto out1;
580 
581 	parent_class = class_get(class_dev->class);
582 	if (!parent_class)
583 		goto out1;
584 
585 	parent_class_dev = class_device_get(class_dev->parent);
586 
587 	pr_debug("CLASS: registering class device: ID = '%s'\n",
588 		 class_dev->class_id);
589 
590 	/* first, register with generic layer. */
591 	error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
592 	if (error)
593 		goto out2;
594 
595 	if (parent_class_dev)
596 		class_dev->kobj.parent = &parent_class_dev->kobj;
597 	else
598 		class_dev->kobj.parent = &parent_class->subsys.kobj;
599 
600 	error = kobject_add(&class_dev->kobj);
601 	if (error)
602 		goto out2;
603 
604 	/* add the needed attributes to this device */
605 	error = sysfs_create_link(&class_dev->kobj,
606 				  &parent_class->subsys.kobj, "subsystem");
607 	if (error)
608 		goto out3;
609 
610 	error = class_device_create_file(class_dev, &class_uevent_attr);
611 	if (error)
612 		goto out3;
613 
614 	if (MAJOR(class_dev->devt)) {
615 		error = class_device_create_file(class_dev, &class_devt_attr);
616 		if (error)
617 			goto out4;
618 	}
619 
620 	error = class_device_add_attrs(class_dev);
621 	if (error)
622 		goto out5;
623 
624 	if (class_dev->dev) {
625 		error = sysfs_create_link(&class_dev->kobj,
626 					  &class_dev->dev->kobj, "device");
627 		if (error)
628 			goto out6;
629 	}
630 
631 	error = class_device_add_groups(class_dev);
632 	if (error)
633 		goto out7;
634 
635 	error = make_deprecated_class_device_links(class_dev);
636 	if (error)
637 		goto out8;
638 
639 	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
640 
641 	/* notify any interfaces this device is now here */
642 	down(&parent_class->sem);
643 	list_add_tail(&class_dev->node, &parent_class->children);
644 	list_for_each_entry(class_intf, &parent_class->interfaces, node) {
645 		if (class_intf->add)
646 			class_intf->add(class_dev, class_intf);
647 	}
648 	up(&parent_class->sem);
649 
650 	goto out1;
651 
652  out8:
653 	class_device_remove_groups(class_dev);
654  out7:
655 	if (class_dev->dev)
656 		sysfs_remove_link(&class_dev->kobj, "device");
657  out6:
658 	class_device_remove_attrs(class_dev);
659  out5:
660 	if (MAJOR(class_dev->devt))
661 		class_device_remove_file(class_dev, &class_devt_attr);
662  out4:
663 	class_device_remove_file(class_dev, &class_uevent_attr);
664  out3:
665 	kobject_del(&class_dev->kobj);
666  out2:
667 	if(parent_class_dev)
668 		class_device_put(parent_class_dev);
669 	class_put(parent_class);
670  out1:
671 	class_device_put(class_dev);
672 	return error;
673 }
674 
675 int class_device_register(struct class_device *class_dev)
676 {
677 	class_device_initialize(class_dev);
678 	return class_device_add(class_dev);
679 }
680 
681 /**
682  * class_device_create - creates a class device and registers it with sysfs
683  * @cls: pointer to the struct class that this device should be registered to.
684  * @parent: pointer to the parent struct class_device of this new device, if any.
685  * @devt: the dev_t for the char device to be added.
686  * @device: a pointer to a struct device that is assiociated with this class device.
687  * @fmt: string for the class device's name
688  *
689  * This function can be used by char device classes.  A struct
690  * class_device will be created in sysfs, registered to the specified
691  * class.
692  * A "dev" file will be created, showing the dev_t for the device, if
693  * the dev_t is not 0,0.
694  * If a pointer to a parent struct class_device is passed in, the newly
695  * created struct class_device will be a child of that device in sysfs.
696  * The pointer to the struct class_device will be returned from the
697  * call.  Any further sysfs files that might be required can be created
698  * using this pointer.
699  *
700  * Note: the struct class passed to this function must have previously
701  * been created with a call to class_create().
702  */
703 struct class_device *class_device_create(struct class *cls,
704 					 struct class_device *parent,
705 					 dev_t devt,
706 					 struct device *device,
707 					 const char *fmt, ...)
708 {
709 	va_list args;
710 	struct class_device *class_dev = NULL;
711 	int retval = -ENODEV;
712 
713 	if (cls == NULL || IS_ERR(cls))
714 		goto error;
715 
716 	class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
717 	if (!class_dev) {
718 		retval = -ENOMEM;
719 		goto error;
720 	}
721 
722 	class_dev->devt = devt;
723 	class_dev->dev = device;
724 	class_dev->class = cls;
725 	class_dev->parent = parent;
726 	class_dev->release = class_device_create_release;
727 	class_dev->uevent = class_device_create_uevent;
728 
729 	va_start(args, fmt);
730 	vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
731 	va_end(args);
732 	retval = class_device_register(class_dev);
733 	if (retval)
734 		goto error;
735 
736 	return class_dev;
737 
738 error:
739 	kfree(class_dev);
740 	return ERR_PTR(retval);
741 }
742 
743 void class_device_del(struct class_device *class_dev)
744 {
745 	struct class *parent_class = class_dev->class;
746 	struct class_device *parent_device = class_dev->parent;
747 	struct class_interface *class_intf;
748 
749 	if (parent_class) {
750 		down(&parent_class->sem);
751 		list_del_init(&class_dev->node);
752 		list_for_each_entry(class_intf, &parent_class->interfaces, node)
753 			if (class_intf->remove)
754 				class_intf->remove(class_dev, class_intf);
755 		up(&parent_class->sem);
756 	}
757 
758 	if (class_dev->dev) {
759 		remove_deprecated_class_device_links(class_dev);
760 		sysfs_remove_link(&class_dev->kobj, "device");
761 	}
762 	sysfs_remove_link(&class_dev->kobj, "subsystem");
763 	class_device_remove_file(class_dev, &class_uevent_attr);
764 	if (MAJOR(class_dev->devt))
765 		class_device_remove_file(class_dev, &class_devt_attr);
766 	class_device_remove_attrs(class_dev);
767 	class_device_remove_groups(class_dev);
768 
769 	kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
770 	kobject_del(&class_dev->kobj);
771 
772 	class_device_put(parent_device);
773 	class_put(parent_class);
774 }
775 
776 void class_device_unregister(struct class_device *class_dev)
777 {
778 	pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
779 		 class_dev->class_id);
780 	class_device_del(class_dev);
781 	class_device_put(class_dev);
782 }
783 
784 /**
785  * class_device_destroy - removes a class device that was created with class_device_create()
786  * @cls: the pointer to the struct class that this device was registered * with.
787  * @devt: the dev_t of the device that was previously registered.
788  *
789  * This call unregisters and cleans up a class device that was created with a
790  * call to class_device_create()
791  */
792 void class_device_destroy(struct class *cls, dev_t devt)
793 {
794 	struct class_device *class_dev = NULL;
795 	struct class_device *class_dev_tmp;
796 
797 	down(&cls->sem);
798 	list_for_each_entry(class_dev_tmp, &cls->children, node) {
799 		if (class_dev_tmp->devt == devt) {
800 			class_dev = class_dev_tmp;
801 			break;
802 		}
803 	}
804 	up(&cls->sem);
805 
806 	if (class_dev)
807 		class_device_unregister(class_dev);
808 }
809 
810 struct class_device * class_device_get(struct class_device *class_dev)
811 {
812 	if (class_dev)
813 		return to_class_dev(kobject_get(&class_dev->kobj));
814 	return NULL;
815 }
816 
817 void class_device_put(struct class_device *class_dev)
818 {
819 	if (class_dev)
820 		kobject_put(&class_dev->kobj);
821 }
822 
823 
824 int class_interface_register(struct class_interface *class_intf)
825 {
826 	struct class *parent;
827 	struct class_device *class_dev;
828 	struct device *dev;
829 
830 	if (!class_intf || !class_intf->class)
831 		return -ENODEV;
832 
833 	parent = class_get(class_intf->class);
834 	if (!parent)
835 		return -EINVAL;
836 
837 	down(&parent->sem);
838 	list_add_tail(&class_intf->node, &parent->interfaces);
839 	if (class_intf->add) {
840 		list_for_each_entry(class_dev, &parent->children, node)
841 			class_intf->add(class_dev, class_intf);
842 	}
843 	if (class_intf->add_dev) {
844 		list_for_each_entry(dev, &parent->devices, node)
845 			class_intf->add_dev(dev, class_intf);
846 	}
847 	up(&parent->sem);
848 
849 	return 0;
850 }
851 
852 void class_interface_unregister(struct class_interface *class_intf)
853 {
854 	struct class * parent = class_intf->class;
855 	struct class_device *class_dev;
856 	struct device *dev;
857 
858 	if (!parent)
859 		return;
860 
861 	down(&parent->sem);
862 	list_del_init(&class_intf->node);
863 	if (class_intf->remove) {
864 		list_for_each_entry(class_dev, &parent->children, node)
865 			class_intf->remove(class_dev, class_intf);
866 	}
867 	if (class_intf->remove_dev) {
868 		list_for_each_entry(dev, &parent->devices, node)
869 			class_intf->remove_dev(dev, class_intf);
870 	}
871 	up(&parent->sem);
872 
873 	class_put(parent);
874 }
875 
876 int __init classes_init(void)
877 {
878 	int retval;
879 
880 	retval = subsystem_register(&class_subsys);
881 	if (retval)
882 		return retval;
883 
884 	/* ick, this is ugly, the things we go through to keep from showing up
885 	 * in sysfs... */
886 	subsystem_init(&class_obj_subsys);
887 	if (!class_obj_subsys.kobj.parent)
888 		class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
889 	return 0;
890 }
891 
892 EXPORT_SYMBOL_GPL(class_create_file);
893 EXPORT_SYMBOL_GPL(class_remove_file);
894 EXPORT_SYMBOL_GPL(class_register);
895 EXPORT_SYMBOL_GPL(class_unregister);
896 EXPORT_SYMBOL_GPL(class_create);
897 EXPORT_SYMBOL_GPL(class_destroy);
898 
899 EXPORT_SYMBOL_GPL(class_device_register);
900 EXPORT_SYMBOL_GPL(class_device_unregister);
901 EXPORT_SYMBOL_GPL(class_device_initialize);
902 EXPORT_SYMBOL_GPL(class_device_add);
903 EXPORT_SYMBOL_GPL(class_device_del);
904 EXPORT_SYMBOL_GPL(class_device_get);
905 EXPORT_SYMBOL_GPL(class_device_put);
906 EXPORT_SYMBOL_GPL(class_device_create);
907 EXPORT_SYMBOL_GPL(class_device_destroy);
908 EXPORT_SYMBOL_GPL(class_device_create_file);
909 EXPORT_SYMBOL_GPL(class_device_remove_file);
910 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
911 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
912 
913 EXPORT_SYMBOL_GPL(class_interface_register);
914 EXPORT_SYMBOL_GPL(class_interface_unregister);
915