xref: /linux/drivers/base/class.c (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
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.kset.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.kset.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.kset.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 	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 char *make_class_name(const char *name, struct kobject *kobj)
508 {
509 	char *class_name;
510 	int size;
511 
512 	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
513 
514 	class_name = kmalloc(size, GFP_KERNEL);
515 	if (!class_name)
516 		return ERR_PTR(-ENOMEM);
517 
518 	strcpy(class_name, name);
519 	strcat(class_name, ":");
520 	strcat(class_name, kobject_name(kobj));
521 	return class_name;
522 }
523 
524 int class_device_add(struct class_device *class_dev)
525 {
526 	struct class *parent_class = NULL;
527 	struct class_device *parent_class_dev = NULL;
528 	struct class_interface *class_intf;
529 	char *class_name = NULL;
530 	int error = -EINVAL;
531 
532 	class_dev = class_device_get(class_dev);
533 	if (!class_dev)
534 		return -EINVAL;
535 
536 	if (!strlen(class_dev->class_id))
537 		goto out1;
538 
539 	parent_class = class_get(class_dev->class);
540 	if (!parent_class)
541 		goto out1;
542 
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 	error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
550 	if (error)
551 		goto out2;
552 
553 	if (parent_class_dev)
554 		class_dev->kobj.parent = &parent_class_dev->kobj;
555 	else
556 		class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
557 
558 	error = kobject_add(&class_dev->kobj);
559 	if (error)
560 		goto out2;
561 
562 	/* add the needed attributes to this device */
563 	sysfs_create_link(&class_dev->kobj, &parent_class->subsys.kset.kobj, "subsystem");
564 	class_dev->uevent_attr.attr.name = "uevent";
565 	class_dev->uevent_attr.attr.mode = S_IWUSR;
566 	class_dev->uevent_attr.attr.owner = parent_class->owner;
567 	class_dev->uevent_attr.store = store_uevent;
568 	error = class_device_create_file(class_dev, &class_dev->uevent_attr);
569 	if (error)
570 		goto out3;
571 
572 	if (MAJOR(class_dev->devt)) {
573 		struct class_device_attribute *attr;
574 		attr = kzalloc(sizeof(*attr), GFP_KERNEL);
575 		if (!attr) {
576 			error = -ENOMEM;
577 			goto out4;
578 		}
579 		attr->attr.name = "dev";
580 		attr->attr.mode = S_IRUGO;
581 		attr->attr.owner = parent_class->owner;
582 		attr->show = show_dev;
583 		error = class_device_create_file(class_dev, attr);
584 		if (error) {
585 			kfree(attr);
586 			goto out4;
587 		}
588 
589 		class_dev->devt_attr = attr;
590 	}
591 
592 	error = class_device_add_attrs(class_dev);
593 	if (error)
594 		goto out5;
595 
596 	if (class_dev->dev) {
597 		class_name = make_class_name(class_dev->class->name,
598 					     &class_dev->kobj);
599 		error = sysfs_create_link(&class_dev->kobj,
600 					  &class_dev->dev->kobj, "device");
601 		if (error)
602 			goto out6;
603 		error = sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
604 					  class_name);
605 		if (error)
606 			goto out7;
607 	}
608 
609 	error = class_device_add_groups(class_dev);
610 	if (error)
611 		goto out8;
612 
613 	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
614 
615 	/* notify any interfaces this device is now here */
616 	down(&parent_class->sem);
617 	list_add_tail(&class_dev->node, &parent_class->children);
618 	list_for_each_entry(class_intf, &parent_class->interfaces, node) {
619 		if (class_intf->add)
620 			class_intf->add(class_dev, class_intf);
621 	}
622 	up(&parent_class->sem);
623 
624 	goto out1;
625 
626  out8:
627 	if (class_dev->dev)
628 		sysfs_remove_link(&class_dev->kobj, class_name);
629  out7:
630 	if (class_dev->dev)
631 		sysfs_remove_link(&class_dev->kobj, "device");
632  out6:
633 	class_device_remove_attrs(class_dev);
634  out5:
635 	if (class_dev->devt_attr)
636 		class_device_remove_file(class_dev, class_dev->devt_attr);
637  out4:
638 	class_device_remove_file(class_dev, &class_dev->uevent_attr);
639  out3:
640 	kobject_del(&class_dev->kobj);
641  out2:
642 	if(parent_class_dev)
643 		class_device_put(parent_class_dev);
644 	class_put(parent_class);
645  out1:
646 	class_device_put(class_dev);
647 	kfree(class_name);
648 	return error;
649 }
650 
651 int class_device_register(struct class_device *class_dev)
652 {
653 	class_device_initialize(class_dev);
654 	return class_device_add(class_dev);
655 }
656 
657 /**
658  * class_device_create - creates a class device and registers it with sysfs
659  * @cs: pointer to the struct class that this device should be registered to.
660  * @parent: pointer to the parent struct class_device of this new device, if any.
661  * @dev: the dev_t for the char device to be added.
662  * @device: a pointer to a struct device that is assiociated with this class device.
663  * @fmt: string for the class device's name
664  *
665  * This function can be used by char device classes.  A struct
666  * class_device will be created in sysfs, registered to the specified
667  * class.
668  * A "dev" file will be created, showing the dev_t for the device, if
669  * the dev_t is not 0,0.
670  * If a pointer to a parent struct class_device is passed in, the newly
671  * created struct class_device will be a child of that device in sysfs.
672  * The pointer to the struct class_device will be returned from the
673  * call.  Any further sysfs files that might be required can be created
674  * using this pointer.
675  *
676  * Note: the struct class passed to this function must have previously
677  * been created with a call to class_create().
678  */
679 struct class_device *class_device_create(struct class *cls,
680 					 struct class_device *parent,
681 					 dev_t devt,
682 					 struct device *device, char *fmt, ...)
683 {
684 	va_list args;
685 	struct class_device *class_dev = NULL;
686 	int retval = -ENODEV;
687 
688 	if (cls == NULL || IS_ERR(cls))
689 		goto error;
690 
691 	class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
692 	if (!class_dev) {
693 		retval = -ENOMEM;
694 		goto error;
695 	}
696 
697 	class_dev->devt = devt;
698 	class_dev->dev = device;
699 	class_dev->class = cls;
700 	class_dev->parent = parent;
701 	class_dev->release = class_device_create_release;
702 	class_dev->uevent = class_device_create_uevent;
703 
704 	va_start(args, fmt);
705 	vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
706 	va_end(args);
707 	retval = class_device_register(class_dev);
708 	if (retval)
709 		goto error;
710 
711 	return class_dev;
712 
713 error:
714 	kfree(class_dev);
715 	return ERR_PTR(retval);
716 }
717 
718 void class_device_del(struct class_device *class_dev)
719 {
720 	struct class *parent_class = class_dev->class;
721 	struct class_device *parent_device = class_dev->parent;
722 	struct class_interface *class_intf;
723 	char *class_name = NULL;
724 
725 	if (parent_class) {
726 		down(&parent_class->sem);
727 		list_del_init(&class_dev->node);
728 		list_for_each_entry(class_intf, &parent_class->interfaces, node)
729 			if (class_intf->remove)
730 				class_intf->remove(class_dev, class_intf);
731 		up(&parent_class->sem);
732 	}
733 
734 	if (class_dev->dev) {
735 		class_name = make_class_name(class_dev->class->name,
736 					     &class_dev->kobj);
737 		sysfs_remove_link(&class_dev->kobj, "device");
738 		sysfs_remove_link(&class_dev->dev->kobj, class_name);
739 	}
740 	sysfs_remove_link(&class_dev->kobj, "subsystem");
741 	class_device_remove_file(class_dev, &class_dev->uevent_attr);
742 	if (class_dev->devt_attr)
743 		class_device_remove_file(class_dev, class_dev->devt_attr);
744 	class_device_remove_attrs(class_dev);
745 	class_device_remove_groups(class_dev);
746 
747 	kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
748 	kobject_del(&class_dev->kobj);
749 
750 	class_device_put(parent_device);
751 	class_put(parent_class);
752 	kfree(class_name);
753 }
754 
755 void class_device_unregister(struct class_device *class_dev)
756 {
757 	pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
758 		 class_dev->class_id);
759 	class_device_del(class_dev);
760 	class_device_put(class_dev);
761 }
762 
763 /**
764  * class_device_destroy - removes a class device that was created with class_device_create()
765  * @cls: the pointer to the struct class that this device was registered * with.
766  * @dev: the dev_t of the device that was previously registered.
767  *
768  * This call unregisters and cleans up a class device that was created with a
769  * call to class_device_create()
770  */
771 void class_device_destroy(struct class *cls, dev_t devt)
772 {
773 	struct class_device *class_dev = NULL;
774 	struct class_device *class_dev_tmp;
775 
776 	down(&cls->sem);
777 	list_for_each_entry(class_dev_tmp, &cls->children, node) {
778 		if (class_dev_tmp->devt == devt) {
779 			class_dev = class_dev_tmp;
780 			break;
781 		}
782 	}
783 	up(&cls->sem);
784 
785 	if (class_dev)
786 		class_device_unregister(class_dev);
787 }
788 
789 int class_device_rename(struct class_device *class_dev, char *new_name)
790 {
791 	int error = 0;
792 	char *old_class_name = NULL, *new_class_name = NULL;
793 
794 	class_dev = class_device_get(class_dev);
795 	if (!class_dev)
796 		return -EINVAL;
797 
798 	pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
799 		 new_name);
800 
801 	if (class_dev->dev)
802 		old_class_name = make_class_name(class_dev->class->name,
803 						 &class_dev->kobj);
804 
805 	strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
806 
807 	error = kobject_rename(&class_dev->kobj, new_name);
808 
809 	if (class_dev->dev) {
810 		new_class_name = make_class_name(class_dev->class->name,
811 						 &class_dev->kobj);
812 		sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
813 				  new_class_name);
814 		sysfs_remove_link(&class_dev->dev->kobj, old_class_name);
815 	}
816 	class_device_put(class_dev);
817 
818 	kfree(old_class_name);
819 	kfree(new_class_name);
820 
821 	return error;
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 
843 	if (!class_intf || !class_intf->class)
844 		return -ENODEV;
845 
846 	parent = class_get(class_intf->class);
847 	if (!parent)
848 		return -EINVAL;
849 
850 	down(&parent->sem);
851 	list_add_tail(&class_intf->node, &parent->interfaces);
852 	if (class_intf->add) {
853 		list_for_each_entry(class_dev, &parent->children, node)
854 			class_intf->add(class_dev, class_intf);
855 	}
856 	up(&parent->sem);
857 
858 	return 0;
859 }
860 
861 void class_interface_unregister(struct class_interface *class_intf)
862 {
863 	struct class * parent = class_intf->class;
864 	struct class_device *class_dev;
865 
866 	if (!parent)
867 		return;
868 
869 	down(&parent->sem);
870 	list_del_init(&class_intf->node);
871 	if (class_intf->remove) {
872 		list_for_each_entry(class_dev, &parent->children, node)
873 			class_intf->remove(class_dev, class_intf);
874 	}
875 	up(&parent->sem);
876 
877 	class_put(parent);
878 }
879 
880 
881 
882 int __init classes_init(void)
883 {
884 	int retval;
885 
886 	retval = subsystem_register(&class_subsys);
887 	if (retval)
888 		return retval;
889 
890 	/* ick, this is ugly, the things we go through to keep from showing up
891 	 * in sysfs... */
892 	subsystem_init(&class_obj_subsys);
893 	if (!class_obj_subsys.kset.subsys)
894 			class_obj_subsys.kset.subsys = &class_obj_subsys;
895 	return 0;
896 }
897 
898 EXPORT_SYMBOL_GPL(class_create_file);
899 EXPORT_SYMBOL_GPL(class_remove_file);
900 EXPORT_SYMBOL_GPL(class_register);
901 EXPORT_SYMBOL_GPL(class_unregister);
902 EXPORT_SYMBOL_GPL(class_create);
903 EXPORT_SYMBOL_GPL(class_destroy);
904 
905 EXPORT_SYMBOL_GPL(class_device_register);
906 EXPORT_SYMBOL_GPL(class_device_unregister);
907 EXPORT_SYMBOL_GPL(class_device_initialize);
908 EXPORT_SYMBOL_GPL(class_device_add);
909 EXPORT_SYMBOL_GPL(class_device_del);
910 EXPORT_SYMBOL_GPL(class_device_get);
911 EXPORT_SYMBOL_GPL(class_device_put);
912 EXPORT_SYMBOL_GPL(class_device_create);
913 EXPORT_SYMBOL_GPL(class_device_destroy);
914 EXPORT_SYMBOL_GPL(class_device_create_file);
915 EXPORT_SYMBOL_GPL(class_device_remove_file);
916 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
917 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
918 
919 EXPORT_SYMBOL_GPL(class_interface_register);
920 EXPORT_SYMBOL_GPL(class_interface_unregister);
921