xref: /linux/drivers/base/class.c (revision f3d9478b2ce468c3115b02ecae7e975990697f15)
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 static 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 static 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->devices);
146 	INIT_LIST_HEAD(&cls->interfaces);
147 	init_MUTEX(&cls->sem);
148 	error = kobject_set_name(&cls->subsys.kset.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, 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  * @cs: 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 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
355 			 int num_envp, char *buffer, int buffer_size)
356 {
357 	struct class_device *class_dev = to_class_dev(kobj);
358 	int i = 0;
359 	int length = 0;
360 	int retval = 0;
361 
362 	pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
363 
364 	if (class_dev->dev) {
365 		/* add physical device, backing this device  */
366 		struct device *dev = class_dev->dev;
367 		char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
368 
369 		add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
370 			       &length, "PHYSDEVPATH=%s", path);
371 		kfree(path);
372 
373 		if (dev->bus)
374 			add_uevent_var(envp, num_envp, &i,
375 				       buffer, buffer_size, &length,
376 				       "PHYSDEVBUS=%s", dev->bus->name);
377 
378 		if (dev->driver)
379 			add_uevent_var(envp, num_envp, &i,
380 				       buffer, buffer_size, &length,
381 				       "PHYSDEVDRIVER=%s", dev->driver->name);
382 	}
383 
384 	if (MAJOR(class_dev->devt)) {
385 		add_uevent_var(envp, num_envp, &i,
386 			       buffer, buffer_size, &length,
387 			       "MAJOR=%u", MAJOR(class_dev->devt));
388 
389 		add_uevent_var(envp, num_envp, &i,
390 			       buffer, buffer_size, &length,
391 			       "MINOR=%u", MINOR(class_dev->devt));
392 	}
393 
394 	/* terminate, set to next free slot, shrink available space */
395 	envp[i] = NULL;
396 	envp = &envp[i];
397 	num_envp -= i;
398 	buffer = &buffer[length];
399 	buffer_size -= length;
400 
401 	if (class_dev->uevent) {
402 		/* have the class device specific function add its stuff */
403 		retval = class_dev->uevent(class_dev, envp, num_envp,
404 					    buffer, buffer_size);
405 		if (retval)
406 			pr_debug("class_dev->uevent() returned %d\n", retval);
407 	} else if (class_dev->class->uevent) {
408 		/* have the class specific function add its stuff */
409 		retval = class_dev->class->uevent(class_dev, envp, num_envp,
410 						   buffer, buffer_size);
411 		if (retval)
412 			pr_debug("class->uevent() returned %d\n", retval);
413 	}
414 
415 	return retval;
416 }
417 
418 static struct kset_uevent_ops class_uevent_ops = {
419 	.filter =	class_uevent_filter,
420 	.name =		class_uevent_name,
421 	.uevent =	class_uevent,
422 };
423 
424 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
425 
426 
427 static int class_device_add_attrs(struct class_device * cd)
428 {
429 	int i;
430 	int error = 0;
431 	struct class * cls = cd->class;
432 
433 	if (cls->class_dev_attrs) {
434 		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
435 			error = class_device_create_file(cd,
436 							 &cls->class_dev_attrs[i]);
437 			if (error)
438 				goto Err;
439 		}
440 	}
441  Done:
442 	return error;
443  Err:
444 	while (--i >= 0)
445 		class_device_remove_file(cd,&cls->class_dev_attrs[i]);
446 	goto Done;
447 }
448 
449 static void class_device_remove_attrs(struct class_device * cd)
450 {
451 	int i;
452 	struct class * cls = cd->class;
453 
454 	if (cls->class_dev_attrs) {
455 		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
456 			class_device_remove_file(cd,&cls->class_dev_attrs[i]);
457 	}
458 }
459 
460 static int class_device_add_groups(struct class_device * cd)
461 {
462 	int i;
463 	int error = 0;
464 
465 	if (cd->groups) {
466 		for (i = 0; cd->groups[i]; i++) {
467 			error = sysfs_create_group(&cd->kobj, cd->groups[i]);
468 			if (error) {
469 				while (--i >= 0)
470 					sysfs_remove_group(&cd->kobj, cd->groups[i]);
471 				goto out;
472 			}
473 		}
474 	}
475 out:
476 	return error;
477 }
478 
479 static void class_device_remove_groups(struct class_device * cd)
480 {
481 	int i;
482 	if (cd->groups) {
483 		for (i = 0; cd->groups[i]; i++) {
484 			sysfs_remove_group(&cd->kobj, cd->groups[i]);
485 		}
486 	}
487 }
488 
489 static ssize_t show_dev(struct class_device *class_dev, char *buf)
490 {
491 	return print_dev_t(buf, class_dev->devt);
492 }
493 
494 static ssize_t store_uevent(struct class_device *class_dev,
495 			    const char *buf, size_t count)
496 {
497 	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
498 	return count;
499 }
500 
501 void class_device_initialize(struct class_device *class_dev)
502 {
503 	kobj_set_kset_s(class_dev, class_obj_subsys);
504 	kobject_init(&class_dev->kobj);
505 	INIT_LIST_HEAD(&class_dev->node);
506 }
507 
508 char *make_class_name(const char *name, struct kobject *kobj)
509 {
510 	char *class_name;
511 	int size;
512 
513 	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
514 
515 	class_name = kmalloc(size, GFP_KERNEL);
516 	if (!class_name)
517 		return ERR_PTR(-ENOMEM);
518 
519 	strcpy(class_name, name);
520 	strcat(class_name, ":");
521 	strcat(class_name, kobject_name(kobj));
522 	return class_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 out1;
539 
540 	parent_class = class_get(class_dev->class);
541 	if (!parent_class)
542 		goto out1;
543 
544 	parent_class_dev = class_device_get(class_dev->parent);
545 
546 	pr_debug("CLASS: registering class device: ID = '%s'\n",
547 		 class_dev->class_id);
548 
549 	/* first, register with generic layer. */
550 	error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
551 	if (error)
552 		goto out2;
553 
554 	if (parent_class_dev)
555 		class_dev->kobj.parent = &parent_class_dev->kobj;
556 	else
557 		class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
558 
559 	error = kobject_add(&class_dev->kobj);
560 	if (error)
561 		goto out2;
562 
563 	/* add the needed attributes to this device */
564 	sysfs_create_link(&class_dev->kobj, &parent_class->subsys.kset.kobj, "subsystem");
565 	class_dev->uevent_attr.attr.name = "uevent";
566 	class_dev->uevent_attr.attr.mode = S_IWUSR;
567 	class_dev->uevent_attr.attr.owner = parent_class->owner;
568 	class_dev->uevent_attr.store = store_uevent;
569 	error = class_device_create_file(class_dev, &class_dev->uevent_attr);
570 	if (error)
571 		goto out3;
572 
573 	if (MAJOR(class_dev->devt)) {
574 		struct class_device_attribute *attr;
575 		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
576 		if (!attr) {
577 			error = -ENOMEM;
578 			goto out4;
579 		}
580 		attr->attr.name = "dev";
581 		attr->attr.mode = S_IRUGO;
582 		attr->attr.owner = parent_class->owner;
583 		attr->show = show_dev;
584 		error = class_device_create_file(class_dev, attr);
585 		if (error) {
586 			kfree(attr);
587 			goto out4;
588 		}
589 
590 		class_dev->devt_attr = attr;
591 	}
592 
593 	error = class_device_add_attrs(class_dev);
594 	if (error)
595 		goto out5;
596 
597 	if (class_dev->dev) {
598 		class_name = make_class_name(class_dev->class->name,
599 					     &class_dev->kobj);
600 		error = sysfs_create_link(&class_dev->kobj,
601 					  &class_dev->dev->kobj, "device");
602 		if (error)
603 			goto out6;
604 		error = sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
605 					  class_name);
606 		if (error)
607 			goto out7;
608 	}
609 
610 	error = class_device_add_groups(class_dev);
611 	if (error)
612 		goto out8;
613 
614 	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
615 
616 	/* notify any interfaces this device is now here */
617 	down(&parent_class->sem);
618 	list_add_tail(&class_dev->node, &parent_class->children);
619 	list_for_each_entry(class_intf, &parent_class->interfaces, node) {
620 		if (class_intf->add)
621 			class_intf->add(class_dev, class_intf);
622 	}
623 	up(&parent_class->sem);
624 
625 	goto out1;
626 
627  out8:
628 	if (class_dev->dev)
629 		sysfs_remove_link(&class_dev->kobj, class_name);
630  out7:
631 	if (class_dev->dev)
632 		sysfs_remove_link(&class_dev->kobj, "device");
633  out6:
634 	class_device_remove_attrs(class_dev);
635  out5:
636 	if (class_dev->devt_attr)
637 		class_device_remove_file(class_dev, class_dev->devt_attr);
638  out4:
639 	class_device_remove_file(class_dev, &class_dev->uevent_attr);
640  out3:
641 	kobject_del(&class_dev->kobj);
642  out2:
643 	if(parent_class_dev)
644 		class_device_put(parent_class_dev);
645 	class_put(parent_class);
646  out1:
647 	class_device_put(class_dev);
648 	kfree(class_name);
649 	return error;
650 }
651 
652 int class_device_register(struct class_device *class_dev)
653 {
654 	class_device_initialize(class_dev);
655 	return class_device_add(class_dev);
656 }
657 
658 /**
659  * class_device_create - creates a class device and registers it with sysfs
660  * @cs: pointer to the struct class that this device should be registered to.
661  * @parent: pointer to the parent struct class_device of this new device, if any.
662  * @dev: the dev_t for the char device to be added.
663  * @device: a pointer to a struct device that is assiociated with this class device.
664  * @fmt: string for the class device's name
665  *
666  * This function can be used by char device classes.  A struct
667  * class_device will be created in sysfs, registered to the specified
668  * class.
669  * A "dev" file will be created, showing the dev_t for the device, if
670  * the dev_t is not 0,0.
671  * If a pointer to a parent struct class_device is passed in, the newly
672  * created struct class_device will be a child of that device in sysfs.
673  * The pointer to the struct class_device will be returned from the
674  * call.  Any further sysfs files that might be required can be created
675  * using this pointer.
676  *
677  * Note: the struct class passed to this function must have previously
678  * been created with a call to class_create().
679  */
680 struct class_device *class_device_create(struct class *cls,
681 					 struct class_device *parent,
682 					 dev_t devt,
683 					 struct device *device, char *fmt, ...)
684 {
685 	va_list args;
686 	struct class_device *class_dev = NULL;
687 	int retval = -ENODEV;
688 
689 	if (cls == NULL || IS_ERR(cls))
690 		goto error;
691 
692 	class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
693 	if (!class_dev) {
694 		retval = -ENOMEM;
695 		goto error;
696 	}
697 
698 	class_dev->devt = devt;
699 	class_dev->dev = device;
700 	class_dev->class = cls;
701 	class_dev->parent = parent;
702 	class_dev->release = class_device_create_release;
703 	class_dev->uevent = class_device_create_uevent;
704 
705 	va_start(args, fmt);
706 	vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
707 	va_end(args);
708 	retval = class_device_register(class_dev);
709 	if (retval)
710 		goto error;
711 
712 	return class_dev;
713 
714 error:
715 	kfree(class_dev);
716 	return ERR_PTR(retval);
717 }
718 
719 void class_device_del(struct class_device *class_dev)
720 {
721 	struct class *parent_class = class_dev->class;
722 	struct class_device *parent_device = class_dev->parent;
723 	struct class_interface *class_intf;
724 	char *class_name = NULL;
725 
726 	if (parent_class) {
727 		down(&parent_class->sem);
728 		list_del_init(&class_dev->node);
729 		list_for_each_entry(class_intf, &parent_class->interfaces, node)
730 			if (class_intf->remove)
731 				class_intf->remove(class_dev, class_intf);
732 		up(&parent_class->sem);
733 	}
734 
735 	if (class_dev->dev) {
736 		class_name = make_class_name(class_dev->class->name,
737 					     &class_dev->kobj);
738 		sysfs_remove_link(&class_dev->kobj, "device");
739 		sysfs_remove_link(&class_dev->dev->kobj, class_name);
740 	}
741 	sysfs_remove_link(&class_dev->kobj, "subsystem");
742 	class_device_remove_file(class_dev, &class_dev->uevent_attr);
743 	if (class_dev->devt_attr)
744 		class_device_remove_file(class_dev, class_dev->devt_attr);
745 	class_device_remove_attrs(class_dev);
746 	class_device_remove_groups(class_dev);
747 
748 	kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
749 	kobject_del(&class_dev->kobj);
750 
751 	class_device_put(parent_device);
752 	class_put(parent_class);
753 	kfree(class_name);
754 }
755 
756 void class_device_unregister(struct class_device *class_dev)
757 {
758 	pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
759 		 class_dev->class_id);
760 	class_device_del(class_dev);
761 	class_device_put(class_dev);
762 }
763 
764 /**
765  * class_device_destroy - removes a class device that was created with class_device_create()
766  * @cls: the pointer to the struct class that this device was registered * with.
767  * @dev: the dev_t of the device that was previously registered.
768  *
769  * This call unregisters and cleans up a class device that was created with a
770  * call to class_device_create()
771  */
772 void class_device_destroy(struct class *cls, dev_t devt)
773 {
774 	struct class_device *class_dev = NULL;
775 	struct class_device *class_dev_tmp;
776 
777 	down(&cls->sem);
778 	list_for_each_entry(class_dev_tmp, &cls->children, node) {
779 		if (class_dev_tmp->devt == devt) {
780 			class_dev = class_dev_tmp;
781 			break;
782 		}
783 	}
784 	up(&cls->sem);
785 
786 	if (class_dev)
787 		class_device_unregister(class_dev);
788 }
789 
790 int class_device_rename(struct class_device *class_dev, char *new_name)
791 {
792 	int error = 0;
793 	char *old_class_name = NULL, *new_class_name = NULL;
794 
795 	class_dev = class_device_get(class_dev);
796 	if (!class_dev)
797 		return -EINVAL;
798 
799 	pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
800 		 new_name);
801 
802 	if (class_dev->dev)
803 		old_class_name = make_class_name(class_dev->class->name,
804 						 &class_dev->kobj);
805 
806 	strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
807 
808 	error = kobject_rename(&class_dev->kobj, new_name);
809 
810 	if (class_dev->dev) {
811 		new_class_name = make_class_name(class_dev->class->name,
812 						 &class_dev->kobj);
813 		sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
814 				  new_class_name);
815 		sysfs_remove_link(&class_dev->dev->kobj, old_class_name);
816 	}
817 	class_device_put(class_dev);
818 
819 	kfree(old_class_name);
820 	kfree(new_class_name);
821 
822 	return error;
823 }
824 
825 struct class_device * class_device_get(struct class_device *class_dev)
826 {
827 	if (class_dev)
828 		return to_class_dev(kobject_get(&class_dev->kobj));
829 	return NULL;
830 }
831 
832 void class_device_put(struct class_device *class_dev)
833 {
834 	if (class_dev)
835 		kobject_put(&class_dev->kobj);
836 }
837 
838 
839 int class_interface_register(struct class_interface *class_intf)
840 {
841 	struct class *parent;
842 	struct class_device *class_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 	up(&parent->sem);
858 
859 	return 0;
860 }
861 
862 void class_interface_unregister(struct class_interface *class_intf)
863 {
864 	struct class * parent = class_intf->class;
865 	struct class_device *class_dev;
866 
867 	if (!parent)
868 		return;
869 
870 	down(&parent->sem);
871 	list_del_init(&class_intf->node);
872 	if (class_intf->remove) {
873 		list_for_each_entry(class_dev, &parent->children, node)
874 			class_intf->remove(class_dev, class_intf);
875 	}
876 	up(&parent->sem);
877 
878 	class_put(parent);
879 }
880 
881 
882 
883 int __init classes_init(void)
884 {
885 	int retval;
886 
887 	retval = subsystem_register(&class_subsys);
888 	if (retval)
889 		return retval;
890 
891 	/* ick, this is ugly, the things we go through to keep from showing up
892 	 * in sysfs... */
893 	subsystem_init(&class_obj_subsys);
894 	if (!class_obj_subsys.kset.subsys)
895 			class_obj_subsys.kset.subsys = &class_obj_subsys;
896 	return 0;
897 }
898 
899 EXPORT_SYMBOL_GPL(class_create_file);
900 EXPORT_SYMBOL_GPL(class_remove_file);
901 EXPORT_SYMBOL_GPL(class_register);
902 EXPORT_SYMBOL_GPL(class_unregister);
903 EXPORT_SYMBOL_GPL(class_create);
904 EXPORT_SYMBOL_GPL(class_destroy);
905 
906 EXPORT_SYMBOL_GPL(class_device_register);
907 EXPORT_SYMBOL_GPL(class_device_unregister);
908 EXPORT_SYMBOL_GPL(class_device_initialize);
909 EXPORT_SYMBOL_GPL(class_device_add);
910 EXPORT_SYMBOL_GPL(class_device_del);
911 EXPORT_SYMBOL_GPL(class_device_get);
912 EXPORT_SYMBOL_GPL(class_device_put);
913 EXPORT_SYMBOL_GPL(class_device_create);
914 EXPORT_SYMBOL_GPL(class_device_destroy);
915 EXPORT_SYMBOL_GPL(class_device_create_file);
916 EXPORT_SYMBOL_GPL(class_device_remove_file);
917 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
918 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
919 
920 EXPORT_SYMBOL_GPL(class_interface_register);
921 EXPORT_SYMBOL_GPL(class_interface_unregister);
922