xref: /openbmc/linux/drivers/base/class.c (revision 64c70b1c)
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 	kfree(cd->devt_attr);
316 	cd->devt_attr = NULL;
317 
318 	if (cd->release)
319 		cd->release(cd);
320 	else if (cls->release)
321 		cls->release(cd);
322 	else {
323 		printk(KERN_ERR "Class Device '%s' does not have a release() function, "
324 			"it is broken and must be fixed.\n",
325 			cd->class_id);
326 		WARN_ON(1);
327 	}
328 }
329 
330 static struct kobj_type ktype_class_device = {
331 	.sysfs_ops	= &class_dev_sysfs_ops,
332 	.release	= class_dev_release,
333 };
334 
335 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
336 {
337 	struct kobj_type *ktype = get_ktype(kobj);
338 
339 	if (ktype == &ktype_class_device) {
340 		struct class_device *class_dev = to_class_dev(kobj);
341 		if (class_dev->class)
342 			return 1;
343 	}
344 	return 0;
345 }
346 
347 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
348 {
349 	struct class_device *class_dev = to_class_dev(kobj);
350 
351 	return class_dev->class->name;
352 }
353 
354 #ifdef CONFIG_SYSFS_DEPRECATED
355 char *make_class_name(const char *name, struct kobject *kobj)
356 {
357 	char *class_name;
358 	int size;
359 
360 	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
361 
362 	class_name = kmalloc(size, GFP_KERNEL);
363 	if (!class_name)
364 		return NULL;
365 
366 	strcpy(class_name, name);
367 	strcat(class_name, ":");
368 	strcat(class_name, kobject_name(kobj));
369 	return class_name;
370 }
371 
372 static int make_deprecated_class_device_links(struct class_device *class_dev)
373 {
374 	char *class_name;
375 	int error;
376 
377 	if (!class_dev->dev)
378 		return 0;
379 
380 	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
381 	if (class_name)
382 		error = sysfs_create_link(&class_dev->dev->kobj,
383 					  &class_dev->kobj, class_name);
384 	else
385 		error = -ENOMEM;
386 	kfree(class_name);
387 	return error;
388 }
389 
390 static void remove_deprecated_class_device_links(struct class_device *class_dev)
391 {
392 	char *class_name;
393 
394 	if (!class_dev->dev)
395 		return;
396 
397 	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
398 	if (class_name)
399 		sysfs_remove_link(&class_dev->dev->kobj, class_name);
400 	kfree(class_name);
401 }
402 #else
403 static inline int make_deprecated_class_device_links(struct class_device *cd)
404 { return 0; }
405 static void remove_deprecated_class_device_links(struct class_device *cd)
406 { }
407 #endif
408 
409 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
410 			 int num_envp, char *buffer, int buffer_size)
411 {
412 	struct class_device *class_dev = to_class_dev(kobj);
413 	struct device *dev = class_dev->dev;
414 	int i = 0;
415 	int length = 0;
416 	int retval = 0;
417 
418 	pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
419 
420 	if (MAJOR(class_dev->devt)) {
421 		add_uevent_var(envp, num_envp, &i,
422 			       buffer, buffer_size, &length,
423 			       "MAJOR=%u", MAJOR(class_dev->devt));
424 
425 		add_uevent_var(envp, num_envp, &i,
426 			       buffer, buffer_size, &length,
427 			       "MINOR=%u", MINOR(class_dev->devt));
428 	}
429 
430 	if (dev) {
431 		const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
432 		if (path) {
433 			add_uevent_var(envp, num_envp, &i,
434 				       buffer, buffer_size, &length,
435 				       "PHYSDEVPATH=%s", path);
436 			kfree(path);
437 		}
438 
439 		if (dev->bus)
440 			add_uevent_var(envp, num_envp, &i,
441 				       buffer, buffer_size, &length,
442 				       "PHYSDEVBUS=%s", dev->bus->name);
443 
444 		if (dev->driver)
445 			add_uevent_var(envp, num_envp, &i,
446 				       buffer, buffer_size, &length,
447 				       "PHYSDEVDRIVER=%s", dev->driver->name);
448 	}
449 
450 	/* terminate, set to next free slot, shrink available space */
451 	envp[i] = NULL;
452 	envp = &envp[i];
453 	num_envp -= i;
454 	buffer = &buffer[length];
455 	buffer_size -= length;
456 
457 	if (class_dev->uevent) {
458 		/* have the class device specific function add its stuff */
459 		retval = class_dev->uevent(class_dev, envp, num_envp,
460 					    buffer, buffer_size);
461 		if (retval)
462 			pr_debug("class_dev->uevent() returned %d\n", retval);
463 	} else if (class_dev->class->uevent) {
464 		/* have the class specific function add its stuff */
465 		retval = class_dev->class->uevent(class_dev, envp, num_envp,
466 						   buffer, buffer_size);
467 		if (retval)
468 			pr_debug("class->uevent() returned %d\n", retval);
469 	}
470 
471 	return retval;
472 }
473 
474 static struct kset_uevent_ops class_uevent_ops = {
475 	.filter =	class_uevent_filter,
476 	.name =		class_uevent_name,
477 	.uevent =	class_uevent,
478 };
479 
480 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
481 
482 
483 static int class_device_add_attrs(struct class_device * cd)
484 {
485 	int i;
486 	int error = 0;
487 	struct class * cls = cd->class;
488 
489 	if (cls->class_dev_attrs) {
490 		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
491 			error = class_device_create_file(cd,
492 							 &cls->class_dev_attrs[i]);
493 			if (error)
494 				goto Err;
495 		}
496 	}
497  Done:
498 	return error;
499  Err:
500 	while (--i >= 0)
501 		class_device_remove_file(cd,&cls->class_dev_attrs[i]);
502 	goto Done;
503 }
504 
505 static void class_device_remove_attrs(struct class_device * cd)
506 {
507 	int i;
508 	struct class * cls = cd->class;
509 
510 	if (cls->class_dev_attrs) {
511 		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
512 			class_device_remove_file(cd,&cls->class_dev_attrs[i]);
513 	}
514 }
515 
516 static int class_device_add_groups(struct class_device * cd)
517 {
518 	int i;
519 	int error = 0;
520 
521 	if (cd->groups) {
522 		for (i = 0; cd->groups[i]; i++) {
523 			error = sysfs_create_group(&cd->kobj, cd->groups[i]);
524 			if (error) {
525 				while (--i >= 0)
526 					sysfs_remove_group(&cd->kobj, cd->groups[i]);
527 				goto out;
528 			}
529 		}
530 	}
531 out:
532 	return error;
533 }
534 
535 static void class_device_remove_groups(struct class_device * cd)
536 {
537 	int i;
538 	if (cd->groups) {
539 		for (i = 0; cd->groups[i]; i++) {
540 			sysfs_remove_group(&cd->kobj, cd->groups[i]);
541 		}
542 	}
543 }
544 
545 static ssize_t show_dev(struct class_device *class_dev, char *buf)
546 {
547 	return print_dev_t(buf, class_dev->devt);
548 }
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 void class_device_initialize(struct class_device *class_dev)
558 {
559 	kobj_set_kset_s(class_dev, class_obj_subsys);
560 	kobject_init(&class_dev->kobj);
561 	INIT_LIST_HEAD(&class_dev->node);
562 }
563 
564 int class_device_add(struct class_device *class_dev)
565 {
566 	struct class *parent_class = NULL;
567 	struct class_device *parent_class_dev = NULL;
568 	struct class_interface *class_intf;
569 	int error = -EINVAL;
570 
571 	class_dev = class_device_get(class_dev);
572 	if (!class_dev)
573 		return -EINVAL;
574 
575 	if (!strlen(class_dev->class_id))
576 		goto out1;
577 
578 	parent_class = class_get(class_dev->class);
579 	if (!parent_class)
580 		goto out1;
581 
582 	parent_class_dev = class_device_get(class_dev->parent);
583 
584 	pr_debug("CLASS: registering class device: ID = '%s'\n",
585 		 class_dev->class_id);
586 
587 	/* first, register with generic layer. */
588 	error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
589 	if (error)
590 		goto out2;
591 
592 	if (parent_class_dev)
593 		class_dev->kobj.parent = &parent_class_dev->kobj;
594 	else
595 		class_dev->kobj.parent = &parent_class->subsys.kobj;
596 
597 	error = kobject_add(&class_dev->kobj);
598 	if (error)
599 		goto out2;
600 
601 	/* add the needed attributes to this device */
602 	error = sysfs_create_link(&class_dev->kobj,
603 				  &parent_class->subsys.kobj, "subsystem");
604 	if (error)
605 		goto out3;
606 	class_dev->uevent_attr.attr.name = "uevent";
607 	class_dev->uevent_attr.attr.mode = S_IWUSR;
608 	class_dev->uevent_attr.attr.owner = parent_class->owner;
609 	class_dev->uevent_attr.store = store_uevent;
610 	error = class_device_create_file(class_dev, &class_dev->uevent_attr);
611 	if (error)
612 		goto out3;
613 
614 	if (MAJOR(class_dev->devt)) {
615 		struct class_device_attribute *attr;
616 		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
617 		if (!attr) {
618 			error = -ENOMEM;
619 			goto out4;
620 		}
621 		attr->attr.name = "dev";
622 		attr->attr.mode = S_IRUGO;
623 		attr->attr.owner = parent_class->owner;
624 		attr->show = show_dev;
625 		error = class_device_create_file(class_dev, attr);
626 		if (error) {
627 			kfree(attr);
628 			goto out4;
629 		}
630 
631 		class_dev->devt_attr = attr;
632 	}
633 
634 	error = class_device_add_attrs(class_dev);
635 	if (error)
636 		goto out5;
637 
638 	if (class_dev->dev) {
639 		error = sysfs_create_link(&class_dev->kobj,
640 					  &class_dev->dev->kobj, "device");
641 		if (error)
642 			goto out6;
643 	}
644 
645 	error = class_device_add_groups(class_dev);
646 	if (error)
647 		goto out7;
648 
649 	error = make_deprecated_class_device_links(class_dev);
650 	if (error)
651 		goto out8;
652 
653 	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
654 
655 	/* notify any interfaces this device is now here */
656 	down(&parent_class->sem);
657 	list_add_tail(&class_dev->node, &parent_class->children);
658 	list_for_each_entry(class_intf, &parent_class->interfaces, node) {
659 		if (class_intf->add)
660 			class_intf->add(class_dev, class_intf);
661 	}
662 	up(&parent_class->sem);
663 
664 	goto out1;
665 
666  out8:
667 	class_device_remove_groups(class_dev);
668  out7:
669 	if (class_dev->dev)
670 		sysfs_remove_link(&class_dev->kobj, "device");
671  out6:
672 	class_device_remove_attrs(class_dev);
673  out5:
674 	if (class_dev->devt_attr)
675 		class_device_remove_file(class_dev, class_dev->devt_attr);
676  out4:
677 	class_device_remove_file(class_dev, &class_dev->uevent_attr);
678  out3:
679 	kobject_del(&class_dev->kobj);
680  out2:
681 	if(parent_class_dev)
682 		class_device_put(parent_class_dev);
683 	class_put(parent_class);
684  out1:
685 	class_device_put(class_dev);
686 	return error;
687 }
688 
689 int class_device_register(struct class_device *class_dev)
690 {
691 	class_device_initialize(class_dev);
692 	return class_device_add(class_dev);
693 }
694 
695 /**
696  * class_device_create - creates a class device and registers it with sysfs
697  * @cls: pointer to the struct class that this device should be registered to.
698  * @parent: pointer to the parent struct class_device of this new device, if any.
699  * @devt: the dev_t for the char device to be added.
700  * @device: a pointer to a struct device that is assiociated with this class device.
701  * @fmt: string for the class device's name
702  *
703  * This function can be used by char device classes.  A struct
704  * class_device will be created in sysfs, registered to the specified
705  * class.
706  * A "dev" file will be created, showing the dev_t for the device, if
707  * the dev_t is not 0,0.
708  * If a pointer to a parent struct class_device is passed in, the newly
709  * created struct class_device will be a child of that device in sysfs.
710  * The pointer to the struct class_device will be returned from the
711  * call.  Any further sysfs files that might be required can be created
712  * using this pointer.
713  *
714  * Note: the struct class passed to this function must have previously
715  * been created with a call to class_create().
716  */
717 struct class_device *class_device_create(struct class *cls,
718 					 struct class_device *parent,
719 					 dev_t devt,
720 					 struct device *device,
721 					 const char *fmt, ...)
722 {
723 	va_list args;
724 	struct class_device *class_dev = NULL;
725 	int retval = -ENODEV;
726 
727 	if (cls == NULL || IS_ERR(cls))
728 		goto error;
729 
730 	class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
731 	if (!class_dev) {
732 		retval = -ENOMEM;
733 		goto error;
734 	}
735 
736 	class_dev->devt = devt;
737 	class_dev->dev = device;
738 	class_dev->class = cls;
739 	class_dev->parent = parent;
740 	class_dev->release = class_device_create_release;
741 	class_dev->uevent = class_device_create_uevent;
742 
743 	va_start(args, fmt);
744 	vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
745 	va_end(args);
746 	retval = class_device_register(class_dev);
747 	if (retval)
748 		goto error;
749 
750 	return class_dev;
751 
752 error:
753 	kfree(class_dev);
754 	return ERR_PTR(retval);
755 }
756 
757 void class_device_del(struct class_device *class_dev)
758 {
759 	struct class *parent_class = class_dev->class;
760 	struct class_device *parent_device = class_dev->parent;
761 	struct class_interface *class_intf;
762 
763 	if (parent_class) {
764 		down(&parent_class->sem);
765 		list_del_init(&class_dev->node);
766 		list_for_each_entry(class_intf, &parent_class->interfaces, node)
767 			if (class_intf->remove)
768 				class_intf->remove(class_dev, class_intf);
769 		up(&parent_class->sem);
770 	}
771 
772 	if (class_dev->dev) {
773 		remove_deprecated_class_device_links(class_dev);
774 		sysfs_remove_link(&class_dev->kobj, "device");
775 	}
776 	sysfs_remove_link(&class_dev->kobj, "subsystem");
777 	class_device_remove_file(class_dev, &class_dev->uevent_attr);
778 	if (class_dev->devt_attr)
779 		class_device_remove_file(class_dev, class_dev->devt_attr);
780 	class_device_remove_attrs(class_dev);
781 	class_device_remove_groups(class_dev);
782 
783 	kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
784 	kobject_del(&class_dev->kobj);
785 
786 	class_device_put(parent_device);
787 	class_put(parent_class);
788 }
789 
790 void class_device_unregister(struct class_device *class_dev)
791 {
792 	pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
793 		 class_dev->class_id);
794 	class_device_del(class_dev);
795 	class_device_put(class_dev);
796 }
797 
798 /**
799  * class_device_destroy - removes a class device that was created with class_device_create()
800  * @cls: the pointer to the struct class that this device was registered * with.
801  * @devt: the dev_t of the device that was previously registered.
802  *
803  * This call unregisters and cleans up a class device that was created with a
804  * call to class_device_create()
805  */
806 void class_device_destroy(struct class *cls, dev_t devt)
807 {
808 	struct class_device *class_dev = NULL;
809 	struct class_device *class_dev_tmp;
810 
811 	down(&cls->sem);
812 	list_for_each_entry(class_dev_tmp, &cls->children, node) {
813 		if (class_dev_tmp->devt == devt) {
814 			class_dev = class_dev_tmp;
815 			break;
816 		}
817 	}
818 	up(&cls->sem);
819 
820 	if (class_dev)
821 		class_device_unregister(class_dev);
822 }
823 
824 struct class_device * class_device_get(struct class_device *class_dev)
825 {
826 	if (class_dev)
827 		return to_class_dev(kobject_get(&class_dev->kobj));
828 	return NULL;
829 }
830 
831 void class_device_put(struct class_device *class_dev)
832 {
833 	if (class_dev)
834 		kobject_put(&class_dev->kobj);
835 }
836 
837 
838 int class_interface_register(struct class_interface *class_intf)
839 {
840 	struct class *parent;
841 	struct class_device *class_dev;
842 	struct device *dev;
843 
844 	if (!class_intf || !class_intf->class)
845 		return -ENODEV;
846 
847 	parent = class_get(class_intf->class);
848 	if (!parent)
849 		return -EINVAL;
850 
851 	down(&parent->sem);
852 	list_add_tail(&class_intf->node, &parent->interfaces);
853 	if (class_intf->add) {
854 		list_for_each_entry(class_dev, &parent->children, node)
855 			class_intf->add(class_dev, class_intf);
856 	}
857 	if (class_intf->add_dev) {
858 		list_for_each_entry(dev, &parent->devices, node)
859 			class_intf->add_dev(dev, class_intf);
860 	}
861 	up(&parent->sem);
862 
863 	return 0;
864 }
865 
866 void class_interface_unregister(struct class_interface *class_intf)
867 {
868 	struct class * parent = class_intf->class;
869 	struct class_device *class_dev;
870 	struct device *dev;
871 
872 	if (!parent)
873 		return;
874 
875 	down(&parent->sem);
876 	list_del_init(&class_intf->node);
877 	if (class_intf->remove) {
878 		list_for_each_entry(class_dev, &parent->children, node)
879 			class_intf->remove(class_dev, class_intf);
880 	}
881 	if (class_intf->remove_dev) {
882 		list_for_each_entry(dev, &parent->devices, node)
883 			class_intf->remove_dev(dev, class_intf);
884 	}
885 	up(&parent->sem);
886 
887 	class_put(parent);
888 }
889 
890 int __init classes_init(void)
891 {
892 	int retval;
893 
894 	retval = subsystem_register(&class_subsys);
895 	if (retval)
896 		return retval;
897 
898 	/* ick, this is ugly, the things we go through to keep from showing up
899 	 * in sysfs... */
900 	subsystem_init(&class_obj_subsys);
901 	if (!class_obj_subsys.kobj.parent)
902 		class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
903 	return 0;
904 }
905 
906 EXPORT_SYMBOL_GPL(class_create_file);
907 EXPORT_SYMBOL_GPL(class_remove_file);
908 EXPORT_SYMBOL_GPL(class_register);
909 EXPORT_SYMBOL_GPL(class_unregister);
910 EXPORT_SYMBOL_GPL(class_create);
911 EXPORT_SYMBOL_GPL(class_destroy);
912 
913 EXPORT_SYMBOL_GPL(class_device_register);
914 EXPORT_SYMBOL_GPL(class_device_unregister);
915 EXPORT_SYMBOL_GPL(class_device_initialize);
916 EXPORT_SYMBOL_GPL(class_device_add);
917 EXPORT_SYMBOL_GPL(class_device_del);
918 EXPORT_SYMBOL_GPL(class_device_get);
919 EXPORT_SYMBOL_GPL(class_device_put);
920 EXPORT_SYMBOL_GPL(class_device_create);
921 EXPORT_SYMBOL_GPL(class_device_destroy);
922 EXPORT_SYMBOL_GPL(class_device_create_file);
923 EXPORT_SYMBOL_GPL(class_device_remove_file);
924 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
925 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
926 
927 EXPORT_SYMBOL_GPL(class_interface_register);
928 EXPORT_SYMBOL_GPL(class_interface_unregister);
929