Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * class.c - basic device class management
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2003-2004 Greg Kroah-Hartman
8 * Copyright (c) 2003-2004 IBM Corp.
9 */
10
11#include <linux/device/class.h>
12#include <linux/device.h>
13#include <linux/module.h>
14#include <linux/init.h>
15#include <linux/string.h>
16#include <linux/kdev_t.h>
17#include <linux/err.h>
18#include <linux/slab.h>
19#include <linux/blkdev.h>
20#include <linux/mutex.h>
21#include "base.h"
22
23#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
24
25static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
26 char *buf)
27{
28 struct class_attribute *class_attr = to_class_attr(attr);
29 struct subsys_private *cp = to_subsys_private(kobj);
30 ssize_t ret = -EIO;
31
32 if (class_attr->show)
33 ret = class_attr->show(cp->class, class_attr, buf);
34 return ret;
35}
36
37static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr,
38 const char *buf, size_t count)
39{
40 struct class_attribute *class_attr = to_class_attr(attr);
41 struct subsys_private *cp = to_subsys_private(kobj);
42 ssize_t ret = -EIO;
43
44 if (class_attr->store)
45 ret = class_attr->store(cp->class, class_attr, buf, count);
46 return ret;
47}
48
49static void class_release(struct kobject *kobj)
50{
51 struct subsys_private *cp = to_subsys_private(kobj);
52 struct class *class = cp->class;
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 kfree(cp);
63}
64
65static const struct kobj_ns_type_operations *class_child_ns_type(const struct kobject *kobj)
66{
67 struct subsys_private *cp = to_subsys_private(kobj);
68 struct class *class = cp->class;
69
70 return class->ns_type;
71}
72
73static const struct sysfs_ops class_sysfs_ops = {
74 .show = class_attr_show,
75 .store = class_attr_store,
76};
77
78static struct kobj_type class_ktype = {
79 .sysfs_ops = &class_sysfs_ops,
80 .release = class_release,
81 .child_ns_type = class_child_ns_type,
82};
83
84/* Hotplug events for classes go to the class subsys */
85static struct kset *class_kset;
86
87
88int class_create_file_ns(struct class *cls, const struct class_attribute *attr,
89 const void *ns)
90{
91 int error;
92
93 if (cls)
94 error = sysfs_create_file_ns(&cls->p->subsys.kobj,
95 &attr->attr, ns);
96 else
97 error = -EINVAL;
98 return error;
99}
100
101void class_remove_file_ns(struct class *cls, const struct class_attribute *attr,
102 const void *ns)
103{
104 if (cls)
105 sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns);
106}
107
108static struct class *class_get(struct class *cls)
109{
110 if (cls)
111 kset_get(&cls->p->subsys);
112 return cls;
113}
114
115static void class_put(struct class *cls)
116{
117 if (cls)
118 kset_put(&cls->p->subsys);
119}
120
121static struct device *klist_class_to_dev(struct klist_node *n)
122{
123 struct device_private *p = to_device_private_class(n);
124 return p->device;
125}
126
127static void klist_class_dev_get(struct klist_node *n)
128{
129 struct device *dev = klist_class_to_dev(n);
130
131 get_device(dev);
132}
133
134static void klist_class_dev_put(struct klist_node *n)
135{
136 struct device *dev = klist_class_to_dev(n);
137
138 put_device(dev);
139}
140
141static int class_add_groups(struct class *cls,
142 const struct attribute_group **groups)
143{
144 return sysfs_create_groups(&cls->p->subsys.kobj, groups);
145}
146
147static void class_remove_groups(struct class *cls,
148 const struct attribute_group **groups)
149{
150 return sysfs_remove_groups(&cls->p->subsys.kobj, groups);
151}
152
153int __class_register(struct class *cls, struct lock_class_key *key)
154{
155 struct subsys_private *cp;
156 int error;
157
158 pr_debug("device class '%s': registering\n", cls->name);
159
160 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
161 if (!cp)
162 return -ENOMEM;
163 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
164 INIT_LIST_HEAD(&cp->interfaces);
165 kset_init(&cp->glue_dirs);
166 __mutex_init(&cp->mutex, "subsys mutex", key);
167 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
168 if (error) {
169 kfree(cp);
170 return error;
171 }
172
173 /* set the default /sys/dev directory for devices of this class */
174 if (!cls->dev_kobj)
175 cls->dev_kobj = sysfs_dev_char_kobj;
176
177#if defined(CONFIG_BLOCK)
178 /* let the block class directory show up in the root of sysfs */
179 if (!sysfs_deprecated || cls != &block_class)
180 cp->subsys.kobj.kset = class_kset;
181#else
182 cp->subsys.kobj.kset = class_kset;
183#endif
184 cp->subsys.kobj.ktype = &class_ktype;
185 cp->class = cls;
186 cls->p = cp;
187
188 error = kset_register(&cp->subsys);
189 if (error) {
190 kfree(cp);
191 return error;
192 }
193 error = class_add_groups(class_get(cls), cls->class_groups);
194 class_put(cls);
195 if (error) {
196 kobject_del(&cp->subsys.kobj);
197 kfree_const(cp->subsys.kobj.name);
198 kfree(cp);
199 }
200 return error;
201}
202EXPORT_SYMBOL_GPL(__class_register);
203
204void class_unregister(struct class *cls)
205{
206 pr_debug("device class '%s': unregistering\n", cls->name);
207 class_remove_groups(cls, cls->class_groups);
208 kset_unregister(&cls->p->subsys);
209}
210
211static void class_create_release(struct class *cls)
212{
213 pr_debug("%s called for %s\n", __func__, cls->name);
214 kfree(cls);
215}
216
217/**
218 * __class_create - create a struct class structure
219 * @owner: pointer to the module that is to "own" this struct class
220 * @name: pointer to a string for the name of this class.
221 * @key: the lock_class_key for this class; used by mutex lock debugging
222 *
223 * This is used to create a struct class pointer that can then be used
224 * in calls to device_create().
225 *
226 * Returns &struct class pointer on success, or ERR_PTR() on error.
227 *
228 * Note, the pointer created here is to be destroyed when finished by
229 * making a call to class_destroy().
230 */
231struct class *__class_create(struct module *owner, const char *name,
232 struct lock_class_key *key)
233{
234 struct class *cls;
235 int retval;
236
237 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
238 if (!cls) {
239 retval = -ENOMEM;
240 goto error;
241 }
242
243 cls->name = name;
244 cls->owner = owner;
245 cls->class_release = class_create_release;
246
247 retval = __class_register(cls, key);
248 if (retval)
249 goto error;
250
251 return cls;
252
253error:
254 kfree(cls);
255 return ERR_PTR(retval);
256}
257EXPORT_SYMBOL_GPL(__class_create);
258
259/**
260 * class_destroy - destroys a struct class structure
261 * @cls: pointer to the struct class that is to be destroyed
262 *
263 * Note, the pointer to be destroyed must have been created with a call
264 * to class_create().
265 */
266void class_destroy(struct class *cls)
267{
268 if (IS_ERR_OR_NULL(cls))
269 return;
270
271 class_unregister(cls);
272}
273
274/**
275 * class_dev_iter_init - initialize class device iterator
276 * @iter: class iterator to initialize
277 * @class: the class we wanna iterate over
278 * @start: the device to start iterating from, if any
279 * @type: device_type of the devices to iterate over, NULL for all
280 *
281 * Initialize class iterator @iter such that it iterates over devices
282 * of @class. If @start is set, the list iteration will start there,
283 * otherwise if it is NULL, the iteration starts at the beginning of
284 * the list.
285 */
286void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
287 struct device *start, const struct device_type *type)
288{
289 struct klist_node *start_knode = NULL;
290
291 if (start)
292 start_knode = &start->p->knode_class;
293 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
294 iter->type = type;
295}
296EXPORT_SYMBOL_GPL(class_dev_iter_init);
297
298/**
299 * class_dev_iter_next - iterate to the next device
300 * @iter: class iterator to proceed
301 *
302 * Proceed @iter to the next device and return it. Returns NULL if
303 * iteration is complete.
304 *
305 * The returned device is referenced and won't be released till
306 * iterator is proceed to the next device or exited. The caller is
307 * free to do whatever it wants to do with the device including
308 * calling back into class code.
309 */
310struct device *class_dev_iter_next(struct class_dev_iter *iter)
311{
312 struct klist_node *knode;
313 struct device *dev;
314
315 while (1) {
316 knode = klist_next(&iter->ki);
317 if (!knode)
318 return NULL;
319 dev = klist_class_to_dev(knode);
320 if (!iter->type || iter->type == dev->type)
321 return dev;
322 }
323}
324EXPORT_SYMBOL_GPL(class_dev_iter_next);
325
326/**
327 * class_dev_iter_exit - finish iteration
328 * @iter: class iterator to finish
329 *
330 * Finish an iteration. Always call this function after iteration is
331 * complete whether the iteration ran till the end or not.
332 */
333void class_dev_iter_exit(struct class_dev_iter *iter)
334{
335 klist_iter_exit(&iter->ki);
336}
337EXPORT_SYMBOL_GPL(class_dev_iter_exit);
338
339/**
340 * class_for_each_device - device iterator
341 * @class: the class we're iterating
342 * @start: the device to start with in the list, if any.
343 * @data: data for the callback
344 * @fn: function to be called for each device
345 *
346 * Iterate over @class's list of devices, and call @fn for each,
347 * passing it @data. If @start is set, the list iteration will start
348 * there, otherwise if it is NULL, the iteration starts at the
349 * beginning of the list.
350 *
351 * We check the return of @fn each time. If it returns anything
352 * other than 0, we break out and return that value.
353 *
354 * @fn is allowed to do anything including calling back into class
355 * code. There's no locking restriction.
356 */
357int class_for_each_device(struct class *class, struct device *start,
358 void *data, int (*fn)(struct device *, void *))
359{
360 struct class_dev_iter iter;
361 struct device *dev;
362 int error = 0;
363
364 if (!class)
365 return -EINVAL;
366 if (!class->p) {
367 WARN(1, "%s called for class '%s' before it was initialized",
368 __func__, class->name);
369 return -EINVAL;
370 }
371
372 class_dev_iter_init(&iter, class, start, NULL);
373 while ((dev = class_dev_iter_next(&iter))) {
374 error = fn(dev, data);
375 if (error)
376 break;
377 }
378 class_dev_iter_exit(&iter);
379
380 return error;
381}
382EXPORT_SYMBOL_GPL(class_for_each_device);
383
384/**
385 * class_find_device - device iterator for locating a particular device
386 * @class: the class we're iterating
387 * @start: Device to begin with
388 * @data: data for the match function
389 * @match: function to check device
390 *
391 * This is similar to the class_for_each_dev() function above, but it
392 * returns a reference to a device that is 'found' for later use, as
393 * determined by the @match callback.
394 *
395 * The callback should return 0 if the device doesn't match and non-zero
396 * if it does. If the callback returns non-zero, this function will
397 * return to the caller and not iterate over any more devices.
398 *
399 * Note, you will need to drop the reference with put_device() after use.
400 *
401 * @match is allowed to do anything including calling back into class
402 * code. There's no locking restriction.
403 */
404struct device *class_find_device(struct class *class, struct device *start,
405 const void *data,
406 int (*match)(struct device *, const void *))
407{
408 struct class_dev_iter iter;
409 struct device *dev;
410
411 if (!class)
412 return NULL;
413 if (!class->p) {
414 WARN(1, "%s called for class '%s' before it was initialized",
415 __func__, class->name);
416 return NULL;
417 }
418
419 class_dev_iter_init(&iter, class, start, NULL);
420 while ((dev = class_dev_iter_next(&iter))) {
421 if (match(dev, data)) {
422 get_device(dev);
423 break;
424 }
425 }
426 class_dev_iter_exit(&iter);
427
428 return dev;
429}
430EXPORT_SYMBOL_GPL(class_find_device);
431
432int class_interface_register(struct class_interface *class_intf)
433{
434 struct class *parent;
435 struct class_dev_iter iter;
436 struct device *dev;
437
438 if (!class_intf || !class_intf->class)
439 return -ENODEV;
440
441 parent = class_get(class_intf->class);
442 if (!parent)
443 return -EINVAL;
444
445 mutex_lock(&parent->p->mutex);
446 list_add_tail(&class_intf->node, &parent->p->interfaces);
447 if (class_intf->add_dev) {
448 class_dev_iter_init(&iter, parent, NULL, NULL);
449 while ((dev = class_dev_iter_next(&iter)))
450 class_intf->add_dev(dev, class_intf);
451 class_dev_iter_exit(&iter);
452 }
453 mutex_unlock(&parent->p->mutex);
454
455 return 0;
456}
457
458void class_interface_unregister(struct class_interface *class_intf)
459{
460 struct class *parent = class_intf->class;
461 struct class_dev_iter iter;
462 struct device *dev;
463
464 if (!parent)
465 return;
466
467 mutex_lock(&parent->p->mutex);
468 list_del_init(&class_intf->node);
469 if (class_intf->remove_dev) {
470 class_dev_iter_init(&iter, parent, NULL, NULL);
471 while ((dev = class_dev_iter_next(&iter)))
472 class_intf->remove_dev(dev, class_intf);
473 class_dev_iter_exit(&iter);
474 }
475 mutex_unlock(&parent->p->mutex);
476
477 class_put(parent);
478}
479
480ssize_t show_class_attr_string(struct class *class,
481 struct class_attribute *attr, char *buf)
482{
483 struct class_attribute_string *cs;
484
485 cs = container_of(attr, struct class_attribute_string, attr);
486 return sysfs_emit(buf, "%s\n", cs->str);
487}
488
489EXPORT_SYMBOL_GPL(show_class_attr_string);
490
491struct class_compat {
492 struct kobject *kobj;
493};
494
495/**
496 * class_compat_register - register a compatibility class
497 * @name: the name of the class
498 *
499 * Compatibility class are meant as a temporary user-space compatibility
500 * workaround when converting a family of class devices to a bus devices.
501 */
502struct class_compat *class_compat_register(const char *name)
503{
504 struct class_compat *cls;
505
506 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
507 if (!cls)
508 return NULL;
509 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
510 if (!cls->kobj) {
511 kfree(cls);
512 return NULL;
513 }
514 return cls;
515}
516EXPORT_SYMBOL_GPL(class_compat_register);
517
518/**
519 * class_compat_unregister - unregister a compatibility class
520 * @cls: the class to unregister
521 */
522void class_compat_unregister(struct class_compat *cls)
523{
524 kobject_put(cls->kobj);
525 kfree(cls);
526}
527EXPORT_SYMBOL_GPL(class_compat_unregister);
528
529/**
530 * class_compat_create_link - create a compatibility class device link to
531 * a bus device
532 * @cls: the compatibility class
533 * @dev: the target bus device
534 * @device_link: an optional device to which a "device" link should be created
535 */
536int class_compat_create_link(struct class_compat *cls, struct device *dev,
537 struct device *device_link)
538{
539 int error;
540
541 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
542 if (error)
543 return error;
544
545 /*
546 * Optionally add a "device" link (typically to the parent), as a
547 * class device would have one and we want to provide as much
548 * backwards compatibility as possible.
549 */
550 if (device_link) {
551 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
552 "device");
553 if (error)
554 sysfs_remove_link(cls->kobj, dev_name(dev));
555 }
556
557 return error;
558}
559EXPORT_SYMBOL_GPL(class_compat_create_link);
560
561/**
562 * class_compat_remove_link - remove a compatibility class device link to
563 * a bus device
564 * @cls: the compatibility class
565 * @dev: the target bus device
566 * @device_link: an optional device to which a "device" link was previously
567 * created
568 */
569void class_compat_remove_link(struct class_compat *cls, struct device *dev,
570 struct device *device_link)
571{
572 if (device_link)
573 sysfs_remove_link(&dev->kobj, "device");
574 sysfs_remove_link(cls->kobj, dev_name(dev));
575}
576EXPORT_SYMBOL_GPL(class_compat_remove_link);
577
578int __init classes_init(void)
579{
580 class_kset = kset_create_and_add("class", NULL, NULL);
581 if (!class_kset)
582 return -ENOMEM;
583 return 0;
584}
585
586EXPORT_SYMBOL_GPL(class_create_file_ns);
587EXPORT_SYMBOL_GPL(class_remove_file_ns);
588EXPORT_SYMBOL_GPL(class_unregister);
589EXPORT_SYMBOL_GPL(class_destroy);
590
591EXPORT_SYMBOL_GPL(class_interface_register);
592EXPORT_SYMBOL_GPL(class_interface_unregister);
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * class.c - basic device class management
4 *
5 * Copyright (c) 2002-3 Patrick Mochel
6 * Copyright (c) 2002-3 Open Source Development Labs
7 * Copyright (c) 2003-2004 Greg Kroah-Hartman
8 * Copyright (c) 2003-2004 IBM Corp.
9 */
10
11#include <linux/device.h>
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/string.h>
15#include <linux/kdev_t.h>
16#include <linux/err.h>
17#include <linux/slab.h>
18#include <linux/genhd.h>
19#include <linux/mutex.h>
20#include "base.h"
21
22#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
23
24static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
25 char *buf)
26{
27 struct class_attribute *class_attr = to_class_attr(attr);
28 struct subsys_private *cp = to_subsys_private(kobj);
29 ssize_t ret = -EIO;
30
31 if (class_attr->show)
32 ret = class_attr->show(cp->class, class_attr, buf);
33 return ret;
34}
35
36static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr,
37 const char *buf, size_t count)
38{
39 struct class_attribute *class_attr = to_class_attr(attr);
40 struct subsys_private *cp = to_subsys_private(kobj);
41 ssize_t ret = -EIO;
42
43 if (class_attr->store)
44 ret = class_attr->store(cp->class, class_attr, buf, count);
45 return ret;
46}
47
48static void class_release(struct kobject *kobj)
49{
50 struct subsys_private *cp = to_subsys_private(kobj);
51 struct class *class = cp->class;
52
53 pr_debug("class '%s': release.\n", class->name);
54
55 if (class->class_release)
56 class->class_release(class);
57 else
58 pr_debug("class '%s' does not have a release() function, "
59 "be careful\n", class->name);
60
61 kfree(cp);
62}
63
64static const struct kobj_ns_type_operations *class_child_ns_type(struct kobject *kobj)
65{
66 struct subsys_private *cp = to_subsys_private(kobj);
67 struct class *class = cp->class;
68
69 return class->ns_type;
70}
71
72static const struct sysfs_ops class_sysfs_ops = {
73 .show = class_attr_show,
74 .store = class_attr_store,
75};
76
77static struct kobj_type class_ktype = {
78 .sysfs_ops = &class_sysfs_ops,
79 .release = class_release,
80 .child_ns_type = class_child_ns_type,
81};
82
83/* Hotplug events for classes go to the class subsys */
84static struct kset *class_kset;
85
86
87int class_create_file_ns(struct class *cls, const struct class_attribute *attr,
88 const void *ns)
89{
90 int error;
91
92 if (cls)
93 error = sysfs_create_file_ns(&cls->p->subsys.kobj,
94 &attr->attr, ns);
95 else
96 error = -EINVAL;
97 return error;
98}
99
100void class_remove_file_ns(struct class *cls, const struct class_attribute *attr,
101 const void *ns)
102{
103 if (cls)
104 sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns);
105}
106
107static struct class *class_get(struct class *cls)
108{
109 if (cls)
110 kset_get(&cls->p->subsys);
111 return cls;
112}
113
114static void class_put(struct class *cls)
115{
116 if (cls)
117 kset_put(&cls->p->subsys);
118}
119
120static void klist_class_dev_get(struct klist_node *n)
121{
122 struct device *dev = container_of(n, struct device, knode_class);
123
124 get_device(dev);
125}
126
127static void klist_class_dev_put(struct klist_node *n)
128{
129 struct device *dev = container_of(n, struct device, knode_class);
130
131 put_device(dev);
132}
133
134static int class_add_groups(struct class *cls,
135 const struct attribute_group **groups)
136{
137 return sysfs_create_groups(&cls->p->subsys.kobj, groups);
138}
139
140static void class_remove_groups(struct class *cls,
141 const struct attribute_group **groups)
142{
143 return sysfs_remove_groups(&cls->p->subsys.kobj, groups);
144}
145
146int __class_register(struct class *cls, struct lock_class_key *key)
147{
148 struct subsys_private *cp;
149 int error;
150
151 pr_debug("device class '%s': registering\n", cls->name);
152
153 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
154 if (!cp)
155 return -ENOMEM;
156 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
157 INIT_LIST_HEAD(&cp->interfaces);
158 kset_init(&cp->glue_dirs);
159 __mutex_init(&cp->mutex, "subsys mutex", key);
160 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
161 if (error) {
162 kfree(cp);
163 return error;
164 }
165
166 /* set the default /sys/dev directory for devices of this class */
167 if (!cls->dev_kobj)
168 cls->dev_kobj = sysfs_dev_char_kobj;
169
170#if defined(CONFIG_BLOCK)
171 /* let the block class directory show up in the root of sysfs */
172 if (!sysfs_deprecated || cls != &block_class)
173 cp->subsys.kobj.kset = class_kset;
174#else
175 cp->subsys.kobj.kset = class_kset;
176#endif
177 cp->subsys.kobj.ktype = &class_ktype;
178 cp->class = cls;
179 cls->p = cp;
180
181 error = kset_register(&cp->subsys);
182 if (error) {
183 kfree(cp);
184 return error;
185 }
186 error = class_add_groups(class_get(cls), cls->class_groups);
187 class_put(cls);
188 return error;
189}
190EXPORT_SYMBOL_GPL(__class_register);
191
192void class_unregister(struct class *cls)
193{
194 pr_debug("device class '%s': unregistering\n", cls->name);
195 class_remove_groups(cls, cls->class_groups);
196 kset_unregister(&cls->p->subsys);
197}
198
199static void class_create_release(struct class *cls)
200{
201 pr_debug("%s called for %s\n", __func__, cls->name);
202 kfree(cls);
203}
204
205/**
206 * class_create - create a struct class structure
207 * @owner: pointer to the module that is to "own" this struct class
208 * @name: pointer to a string for the name of this class.
209 * @key: the lock_class_key for this class; used by mutex lock debugging
210 *
211 * This is used to create a struct class pointer that can then be used
212 * in calls to device_create().
213 *
214 * Returns &struct class pointer on success, or ERR_PTR() on error.
215 *
216 * Note, the pointer created here is to be destroyed when finished by
217 * making a call to class_destroy().
218 */
219struct class *__class_create(struct module *owner, const char *name,
220 struct lock_class_key *key)
221{
222 struct class *cls;
223 int retval;
224
225 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
226 if (!cls) {
227 retval = -ENOMEM;
228 goto error;
229 }
230
231 cls->name = name;
232 cls->owner = owner;
233 cls->class_release = class_create_release;
234
235 retval = __class_register(cls, key);
236 if (retval)
237 goto error;
238
239 return cls;
240
241error:
242 kfree(cls);
243 return ERR_PTR(retval);
244}
245EXPORT_SYMBOL_GPL(__class_create);
246
247/**
248 * class_destroy - destroys a struct class structure
249 * @cls: pointer to the struct class that is to be destroyed
250 *
251 * Note, the pointer to be destroyed must have been created with a call
252 * to class_create().
253 */
254void class_destroy(struct class *cls)
255{
256 if ((cls == NULL) || (IS_ERR(cls)))
257 return;
258
259 class_unregister(cls);
260}
261
262/**
263 * class_dev_iter_init - initialize class device iterator
264 * @iter: class iterator to initialize
265 * @class: the class we wanna iterate over
266 * @start: the device to start iterating from, if any
267 * @type: device_type of the devices to iterate over, NULL for all
268 *
269 * Initialize class iterator @iter such that it iterates over devices
270 * of @class. If @start is set, the list iteration will start there,
271 * otherwise if it is NULL, the iteration starts at the beginning of
272 * the list.
273 */
274void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
275 struct device *start, const struct device_type *type)
276{
277 struct klist_node *start_knode = NULL;
278
279 if (start)
280 start_knode = &start->knode_class;
281 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
282 iter->type = type;
283}
284EXPORT_SYMBOL_GPL(class_dev_iter_init);
285
286/**
287 * class_dev_iter_next - iterate to the next device
288 * @iter: class iterator to proceed
289 *
290 * Proceed @iter to the next device and return it. Returns NULL if
291 * iteration is complete.
292 *
293 * The returned device is referenced and won't be released till
294 * iterator is proceed to the next device or exited. The caller is
295 * free to do whatever it wants to do with the device including
296 * calling back into class code.
297 */
298struct device *class_dev_iter_next(struct class_dev_iter *iter)
299{
300 struct klist_node *knode;
301 struct device *dev;
302
303 while (1) {
304 knode = klist_next(&iter->ki);
305 if (!knode)
306 return NULL;
307 dev = container_of(knode, struct device, knode_class);
308 if (!iter->type || iter->type == dev->type)
309 return dev;
310 }
311}
312EXPORT_SYMBOL_GPL(class_dev_iter_next);
313
314/**
315 * class_dev_iter_exit - finish iteration
316 * @iter: class iterator to finish
317 *
318 * Finish an iteration. Always call this function after iteration is
319 * complete whether the iteration ran till the end or not.
320 */
321void class_dev_iter_exit(struct class_dev_iter *iter)
322{
323 klist_iter_exit(&iter->ki);
324}
325EXPORT_SYMBOL_GPL(class_dev_iter_exit);
326
327/**
328 * class_for_each_device - device iterator
329 * @class: the class we're iterating
330 * @start: the device to start with in the list, if any.
331 * @data: data for the callback
332 * @fn: function to be called for each device
333 *
334 * Iterate over @class's list of devices, and call @fn for each,
335 * passing it @data. If @start is set, the list iteration will start
336 * there, otherwise if it is NULL, the iteration starts at the
337 * beginning of the list.
338 *
339 * We check the return of @fn each time. If it returns anything
340 * other than 0, we break out and return that value.
341 *
342 * @fn is allowed to do anything including calling back into class
343 * code. There's no locking restriction.
344 */
345int class_for_each_device(struct class *class, struct device *start,
346 void *data, int (*fn)(struct device *, void *))
347{
348 struct class_dev_iter iter;
349 struct device *dev;
350 int error = 0;
351
352 if (!class)
353 return -EINVAL;
354 if (!class->p) {
355 WARN(1, "%s called for class '%s' before it was initialized",
356 __func__, class->name);
357 return -EINVAL;
358 }
359
360 class_dev_iter_init(&iter, class, start, NULL);
361 while ((dev = class_dev_iter_next(&iter))) {
362 error = fn(dev, data);
363 if (error)
364 break;
365 }
366 class_dev_iter_exit(&iter);
367
368 return error;
369}
370EXPORT_SYMBOL_GPL(class_for_each_device);
371
372/**
373 * class_find_device - device iterator for locating a particular device
374 * @class: the class we're iterating
375 * @start: Device to begin with
376 * @data: data for the match function
377 * @match: function to check device
378 *
379 * This is similar to the class_for_each_dev() function above, but it
380 * returns a reference to a device that is 'found' for later use, as
381 * determined by the @match callback.
382 *
383 * The callback should return 0 if the device doesn't match and non-zero
384 * if it does. If the callback returns non-zero, this function will
385 * return to the caller and not iterate over any more devices.
386 *
387 * Note, you will need to drop the reference with put_device() after use.
388 *
389 * @match is allowed to do anything including calling back into class
390 * code. There's no locking restriction.
391 */
392struct device *class_find_device(struct class *class, struct device *start,
393 const void *data,
394 int (*match)(struct device *, const void *))
395{
396 struct class_dev_iter iter;
397 struct device *dev;
398
399 if (!class)
400 return NULL;
401 if (!class->p) {
402 WARN(1, "%s called for class '%s' before it was initialized",
403 __func__, class->name);
404 return NULL;
405 }
406
407 class_dev_iter_init(&iter, class, start, NULL);
408 while ((dev = class_dev_iter_next(&iter))) {
409 if (match(dev, data)) {
410 get_device(dev);
411 break;
412 }
413 }
414 class_dev_iter_exit(&iter);
415
416 return dev;
417}
418EXPORT_SYMBOL_GPL(class_find_device);
419
420int class_interface_register(struct class_interface *class_intf)
421{
422 struct class *parent;
423 struct class_dev_iter iter;
424 struct device *dev;
425
426 if (!class_intf || !class_intf->class)
427 return -ENODEV;
428
429 parent = class_get(class_intf->class);
430 if (!parent)
431 return -EINVAL;
432
433 mutex_lock(&parent->p->mutex);
434 list_add_tail(&class_intf->node, &parent->p->interfaces);
435 if (class_intf->add_dev) {
436 class_dev_iter_init(&iter, parent, NULL, NULL);
437 while ((dev = class_dev_iter_next(&iter)))
438 class_intf->add_dev(dev, class_intf);
439 class_dev_iter_exit(&iter);
440 }
441 mutex_unlock(&parent->p->mutex);
442
443 return 0;
444}
445
446void class_interface_unregister(struct class_interface *class_intf)
447{
448 struct class *parent = class_intf->class;
449 struct class_dev_iter iter;
450 struct device *dev;
451
452 if (!parent)
453 return;
454
455 mutex_lock(&parent->p->mutex);
456 list_del_init(&class_intf->node);
457 if (class_intf->remove_dev) {
458 class_dev_iter_init(&iter, parent, NULL, NULL);
459 while ((dev = class_dev_iter_next(&iter)))
460 class_intf->remove_dev(dev, class_intf);
461 class_dev_iter_exit(&iter);
462 }
463 mutex_unlock(&parent->p->mutex);
464
465 class_put(parent);
466}
467
468ssize_t show_class_attr_string(struct class *class,
469 struct class_attribute *attr, char *buf)
470{
471 struct class_attribute_string *cs;
472
473 cs = container_of(attr, struct class_attribute_string, attr);
474 return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
475}
476
477EXPORT_SYMBOL_GPL(show_class_attr_string);
478
479struct class_compat {
480 struct kobject *kobj;
481};
482
483/**
484 * class_compat_register - register a compatibility class
485 * @name: the name of the class
486 *
487 * Compatibility class are meant as a temporary user-space compatibility
488 * workaround when converting a family of class devices to a bus devices.
489 */
490struct class_compat *class_compat_register(const char *name)
491{
492 struct class_compat *cls;
493
494 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
495 if (!cls)
496 return NULL;
497 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
498 if (!cls->kobj) {
499 kfree(cls);
500 return NULL;
501 }
502 return cls;
503}
504EXPORT_SYMBOL_GPL(class_compat_register);
505
506/**
507 * class_compat_unregister - unregister a compatibility class
508 * @cls: the class to unregister
509 */
510void class_compat_unregister(struct class_compat *cls)
511{
512 kobject_put(cls->kobj);
513 kfree(cls);
514}
515EXPORT_SYMBOL_GPL(class_compat_unregister);
516
517/**
518 * class_compat_create_link - create a compatibility class device link to
519 * a bus device
520 * @cls: the compatibility class
521 * @dev: the target bus device
522 * @device_link: an optional device to which a "device" link should be created
523 */
524int class_compat_create_link(struct class_compat *cls, struct device *dev,
525 struct device *device_link)
526{
527 int error;
528
529 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
530 if (error)
531 return error;
532
533 /*
534 * Optionally add a "device" link (typically to the parent), as a
535 * class device would have one and we want to provide as much
536 * backwards compatibility as possible.
537 */
538 if (device_link) {
539 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
540 "device");
541 if (error)
542 sysfs_remove_link(cls->kobj, dev_name(dev));
543 }
544
545 return error;
546}
547EXPORT_SYMBOL_GPL(class_compat_create_link);
548
549/**
550 * class_compat_remove_link - remove a compatibility class device link to
551 * a bus device
552 * @cls: the compatibility class
553 * @dev: the target bus device
554 * @device_link: an optional device to which a "device" link was previously
555 * created
556 */
557void class_compat_remove_link(struct class_compat *cls, struct device *dev,
558 struct device *device_link)
559{
560 if (device_link)
561 sysfs_remove_link(&dev->kobj, "device");
562 sysfs_remove_link(cls->kobj, dev_name(dev));
563}
564EXPORT_SYMBOL_GPL(class_compat_remove_link);
565
566int __init classes_init(void)
567{
568 class_kset = kset_create_and_add("class", NULL, NULL);
569 if (!class_kset)
570 return -ENOMEM;
571 return 0;
572}
573
574EXPORT_SYMBOL_GPL(class_create_file_ns);
575EXPORT_SYMBOL_GPL(class_remove_file_ns);
576EXPORT_SYMBOL_GPL(class_unregister);
577EXPORT_SYMBOL_GPL(class_destroy);
578
579EXPORT_SYMBOL_GPL(class_interface_register);
580EXPORT_SYMBOL_GPL(class_interface_unregister);