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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 <linux/genhd.h>
21#include <linux/mutex.h>
22#include "base.h"
23
24#define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
25
26static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr,
27 char *buf)
28{
29 struct class_attribute *class_attr = to_class_attr(attr);
30 struct subsys_private *cp = to_subsys_private(kobj);
31 ssize_t ret = -EIO;
32
33 if (class_attr->show)
34 ret = class_attr->show(cp->class, class_attr, buf);
35 return ret;
36}
37
38static ssize_t 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 subsys_private *cp = to_subsys_private(kobj);
43 ssize_t ret = -EIO;
44
45 if (class_attr->store)
46 ret = class_attr->store(cp->class, class_attr, buf, count);
47 return ret;
48}
49
50static void class_release(struct kobject *kobj)
51{
52 struct subsys_private *cp = to_subsys_private(kobj);
53 struct class *class = cp->class;
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 kfree(cp);
64}
65
66static const struct kobj_ns_type_operations *class_child_ns_type(struct kobject *kobj)
67{
68 struct subsys_private *cp = to_subsys_private(kobj);
69 struct class *class = cp->class;
70
71 return class->ns_type;
72}
73
74static const struct sysfs_ops class_sysfs_ops = {
75 .show = class_attr_show,
76 .store = class_attr_store,
77};
78
79static struct kobj_type class_ktype = {
80 .sysfs_ops = &class_sysfs_ops,
81 .release = class_release,
82 .child_ns_type = class_child_ns_type,
83};
84
85/* Hotplug events for classes go to the class subsys */
86static struct kset *class_kset;
87
88
89int class_create_file(struct class *cls, const struct class_attribute *attr)
90{
91 int error;
92 if (cls)
93 error = sysfs_create_file(&cls->p->subsys.kobj,
94 &attr->attr);
95 else
96 error = -EINVAL;
97 return error;
98}
99
100void class_remove_file(struct class *cls, const struct class_attribute *attr)
101{
102 if (cls)
103 sysfs_remove_file(&cls->p->subsys.kobj, &attr->attr);
104}
105
106static struct class *class_get(struct class *cls)
107{
108 if (cls)
109 kset_get(&cls->p->subsys);
110 return cls;
111}
112
113static void class_put(struct class *cls)
114{
115 if (cls)
116 kset_put(&cls->p->subsys);
117}
118
119static int add_class_attrs(struct class *cls)
120{
121 int i;
122 int error = 0;
123
124 if (cls->class_attrs) {
125 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
126 error = class_create_file(cls, &cls->class_attrs[i]);
127 if (error)
128 goto error;
129 }
130 }
131done:
132 return error;
133error:
134 while (--i >= 0)
135 class_remove_file(cls, &cls->class_attrs[i]);
136 goto done;
137}
138
139static void remove_class_attrs(struct class *cls)
140{
141 int i;
142
143 if (cls->class_attrs) {
144 for (i = 0; attr_name(cls->class_attrs[i]); i++)
145 class_remove_file(cls, &cls->class_attrs[i]);
146 }
147}
148
149static void klist_class_dev_get(struct klist_node *n)
150{
151 struct device *dev = container_of(n, struct device, knode_class);
152
153 get_device(dev);
154}
155
156static void klist_class_dev_put(struct klist_node *n)
157{
158 struct device *dev = container_of(n, struct device, knode_class);
159
160 put_device(dev);
161}
162
163int __class_register(struct class *cls, struct lock_class_key *key)
164{
165 struct subsys_private *cp;
166 int error;
167
168 pr_debug("device class '%s': registering\n", cls->name);
169
170 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
171 if (!cp)
172 return -ENOMEM;
173 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
174 INIT_LIST_HEAD(&cp->class_interfaces);
175 kset_init(&cp->glue_dirs);
176 __mutex_init(&cp->class_mutex, "struct class mutex", key);
177 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
178 if (error) {
179 kfree(cp);
180 return error;
181 }
182
183 /* set the default /sys/dev directory for devices of this class */
184 if (!cls->dev_kobj)
185 cls->dev_kobj = sysfs_dev_char_kobj;
186
187#if defined(CONFIG_BLOCK)
188 /* let the block class directory show up in the root of sysfs */
189 if (!sysfs_deprecated || cls != &block_class)
190 cp->subsys.kobj.kset = class_kset;
191#else
192 cp->subsys.kobj.kset = class_kset;
193#endif
194 cp->subsys.kobj.ktype = &class_ktype;
195 cp->class = cls;
196 cls->p = cp;
197
198 error = kset_register(&cp->subsys);
199 if (error) {
200 kfree(cp);
201 return error;
202 }
203 error = add_class_attrs(class_get(cls));
204 class_put(cls);
205 return error;
206}
207EXPORT_SYMBOL_GPL(__class_register);
208
209void class_unregister(struct class *cls)
210{
211 pr_debug("device class '%s': unregistering\n", cls->name);
212 remove_class_attrs(cls);
213 kset_unregister(&cls->p->subsys);
214}
215
216static void class_create_release(struct class *cls)
217{
218 pr_debug("%s called for %s\n", __func__, cls->name);
219 kfree(cls);
220}
221
222/**
223 * class_create - create a struct class structure
224 * @owner: pointer to the module that is to "own" this struct class
225 * @name: pointer to a string for the name of this class.
226 * @key: the lock_class_key for this class; used by mutex lock debugging
227 *
228 * This is used to create a struct class pointer that can then be used
229 * in calls to device_create().
230 *
231 * Returns &struct class pointer on success, or ERR_PTR() on error.
232 *
233 * Note, the pointer created here is to be destroyed when finished by
234 * making a call to class_destroy().
235 */
236struct class *__class_create(struct module *owner, const char *name,
237 struct lock_class_key *key)
238{
239 struct class *cls;
240 int retval;
241
242 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
243 if (!cls) {
244 retval = -ENOMEM;
245 goto error;
246 }
247
248 cls->name = name;
249 cls->owner = owner;
250 cls->class_release = class_create_release;
251
252 retval = __class_register(cls, key);
253 if (retval)
254 goto error;
255
256 return cls;
257
258error:
259 kfree(cls);
260 return ERR_PTR(retval);
261}
262EXPORT_SYMBOL_GPL(__class_create);
263
264/**
265 * class_destroy - destroys a struct class structure
266 * @cls: pointer to the struct class that is to be destroyed
267 *
268 * Note, the pointer to be destroyed must have been created with a call
269 * to class_create().
270 */
271void class_destroy(struct class *cls)
272{
273 if ((cls == NULL) || (IS_ERR(cls)))
274 return;
275
276 class_unregister(cls);
277}
278
279/**
280 * class_dev_iter_init - initialize class device iterator
281 * @iter: class iterator to initialize
282 * @class: the class we wanna iterate over
283 * @start: the device to start iterating from, if any
284 * @type: device_type of the devices to iterate over, NULL for all
285 *
286 * Initialize class iterator @iter such that it iterates over devices
287 * of @class. If @start is set, the list iteration will start there,
288 * otherwise if it is NULL, the iteration starts at the beginning of
289 * the list.
290 */
291void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
292 struct device *start, const struct device_type *type)
293{
294 struct klist_node *start_knode = NULL;
295
296 if (start)
297 start_knode = &start->knode_class;
298 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
299 iter->type = type;
300}
301EXPORT_SYMBOL_GPL(class_dev_iter_init);
302
303/**
304 * class_dev_iter_next - iterate to the next device
305 * @iter: class iterator to proceed
306 *
307 * Proceed @iter to the next device and return it. Returns NULL if
308 * iteration is complete.
309 *
310 * The returned device is referenced and won't be released till
311 * iterator is proceed to the next device or exited. The caller is
312 * free to do whatever it wants to do with the device including
313 * calling back into class code.
314 */
315struct device *class_dev_iter_next(struct class_dev_iter *iter)
316{
317 struct klist_node *knode;
318 struct device *dev;
319
320 while (1) {
321 knode = klist_next(&iter->ki);
322 if (!knode)
323 return NULL;
324 dev = container_of(knode, struct device, knode_class);
325 if (!iter->type || iter->type == dev->type)
326 return dev;
327 }
328}
329EXPORT_SYMBOL_GPL(class_dev_iter_next);
330
331/**
332 * class_dev_iter_exit - finish iteration
333 * @iter: class iterator to finish
334 *
335 * Finish an iteration. Always call this function after iteration is
336 * complete whether the iteration ran till the end or not.
337 */
338void class_dev_iter_exit(struct class_dev_iter *iter)
339{
340 klist_iter_exit(&iter->ki);
341}
342EXPORT_SYMBOL_GPL(class_dev_iter_exit);
343
344/**
345 * class_for_each_device - device iterator
346 * @class: the class we're iterating
347 * @start: the device to start with in the list, if any.
348 * @data: data for the callback
349 * @fn: function to be called for each device
350 *
351 * Iterate over @class's list of devices, and call @fn for each,
352 * passing it @data. If @start is set, the list iteration will start
353 * there, otherwise if it is NULL, the iteration starts at the
354 * beginning of the list.
355 *
356 * We check the return of @fn each time. If it returns anything
357 * other than 0, we break out and return that value.
358 *
359 * @fn is allowed to do anything including calling back into class
360 * code. There's no locking restriction.
361 */
362int class_for_each_device(struct class *class, struct device *start,
363 void *data, int (*fn)(struct device *, void *))
364{
365 struct class_dev_iter iter;
366 struct device *dev;
367 int error = 0;
368
369 if (!class)
370 return -EINVAL;
371 if (!class->p) {
372 WARN(1, "%s called for class '%s' before it was initialized",
373 __func__, class->name);
374 return -EINVAL;
375 }
376
377 class_dev_iter_init(&iter, class, start, NULL);
378 while ((dev = class_dev_iter_next(&iter))) {
379 error = fn(dev, data);
380 if (error)
381 break;
382 }
383 class_dev_iter_exit(&iter);
384
385 return error;
386}
387EXPORT_SYMBOL_GPL(class_for_each_device);
388
389/**
390 * class_find_device - device iterator for locating a particular device
391 * @class: the class we're iterating
392 * @start: Device to begin with
393 * @data: data for the match function
394 * @match: function to check device
395 *
396 * This is similar to the class_for_each_dev() function above, but it
397 * returns a reference to a device that is 'found' for later use, as
398 * determined by the @match callback.
399 *
400 * The callback should return 0 if the device doesn't match and non-zero
401 * if it does. If the callback returns non-zero, this function will
402 * return to the caller and not iterate over any more devices.
403 *
404 * Note, you will need to drop the reference with put_device() after use.
405 *
406 * @fn is allowed to do anything including calling back into class
407 * code. There's no locking restriction.
408 */
409struct device *class_find_device(struct class *class, struct device *start,
410 void *data,
411 int (*match)(struct device *, void *))
412{
413 struct class_dev_iter iter;
414 struct device *dev;
415
416 if (!class)
417 return NULL;
418 if (!class->p) {
419 WARN(1, "%s called for class '%s' before it was initialized",
420 __func__, class->name);
421 return NULL;
422 }
423
424 class_dev_iter_init(&iter, class, start, NULL);
425 while ((dev = class_dev_iter_next(&iter))) {
426 if (match(dev, data)) {
427 get_device(dev);
428 break;
429 }
430 }
431 class_dev_iter_exit(&iter);
432
433 return dev;
434}
435EXPORT_SYMBOL_GPL(class_find_device);
436
437int class_interface_register(struct class_interface *class_intf)
438{
439 struct class *parent;
440 struct class_dev_iter iter;
441 struct device *dev;
442
443 if (!class_intf || !class_intf->class)
444 return -ENODEV;
445
446 parent = class_get(class_intf->class);
447 if (!parent)
448 return -EINVAL;
449
450 mutex_lock(&parent->p->class_mutex);
451 list_add_tail(&class_intf->node, &parent->p->class_interfaces);
452 if (class_intf->add_dev) {
453 class_dev_iter_init(&iter, parent, NULL, NULL);
454 while ((dev = class_dev_iter_next(&iter)))
455 class_intf->add_dev(dev, class_intf);
456 class_dev_iter_exit(&iter);
457 }
458 mutex_unlock(&parent->p->class_mutex);
459
460 return 0;
461}
462
463void class_interface_unregister(struct class_interface *class_intf)
464{
465 struct class *parent = class_intf->class;
466 struct class_dev_iter iter;
467 struct device *dev;
468
469 if (!parent)
470 return;
471
472 mutex_lock(&parent->p->class_mutex);
473 list_del_init(&class_intf->node);
474 if (class_intf->remove_dev) {
475 class_dev_iter_init(&iter, parent, NULL, NULL);
476 while ((dev = class_dev_iter_next(&iter)))
477 class_intf->remove_dev(dev, class_intf);
478 class_dev_iter_exit(&iter);
479 }
480 mutex_unlock(&parent->p->class_mutex);
481
482 class_put(parent);
483}
484
485ssize_t show_class_attr_string(struct class *class,
486 struct class_attribute *attr, char *buf)
487{
488 struct class_attribute_string *cs;
489 cs = container_of(attr, struct class_attribute_string, attr);
490 return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
491}
492
493EXPORT_SYMBOL_GPL(show_class_attr_string);
494
495struct class_compat {
496 struct kobject *kobj;
497};
498
499/**
500 * class_compat_register - register a compatibility class
501 * @name: the name of the class
502 *
503 * Compatibility class are meant as a temporary user-space compatibility
504 * workaround when converting a family of class devices to a bus devices.
505 */
506struct class_compat *class_compat_register(const char *name)
507{
508 struct class_compat *cls;
509
510 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
511 if (!cls)
512 return NULL;
513 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
514 if (!cls->kobj) {
515 kfree(cls);
516 return NULL;
517 }
518 return cls;
519}
520EXPORT_SYMBOL_GPL(class_compat_register);
521
522/**
523 * class_compat_unregister - unregister a compatibility class
524 * @cls: the class to unregister
525 */
526void class_compat_unregister(struct class_compat *cls)
527{
528 kobject_put(cls->kobj);
529 kfree(cls);
530}
531EXPORT_SYMBOL_GPL(class_compat_unregister);
532
533/**
534 * class_compat_create_link - create a compatibility class device link to
535 * a bus device
536 * @cls: the compatibility class
537 * @dev: the target bus device
538 * @device_link: an optional device to which a "device" link should be created
539 */
540int class_compat_create_link(struct class_compat *cls, struct device *dev,
541 struct device *device_link)
542{
543 int error;
544
545 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
546 if (error)
547 return error;
548
549 /*
550 * Optionally add a "device" link (typically to the parent), as a
551 * class device would have one and we want to provide as much
552 * backwards compatibility as possible.
553 */
554 if (device_link) {
555 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
556 "device");
557 if (error)
558 sysfs_remove_link(cls->kobj, dev_name(dev));
559 }
560
561 return error;
562}
563EXPORT_SYMBOL_GPL(class_compat_create_link);
564
565/**
566 * class_compat_remove_link - remove a compatibility class device link to
567 * a bus device
568 * @cls: the compatibility class
569 * @dev: the target bus device
570 * @device_link: an optional device to which a "device" link was previously
571 * created
572 */
573void class_compat_remove_link(struct class_compat *cls, struct device *dev,
574 struct device *device_link)
575{
576 if (device_link)
577 sysfs_remove_link(&dev->kobj, "device");
578 sysfs_remove_link(cls->kobj, dev_name(dev));
579}
580EXPORT_SYMBOL_GPL(class_compat_remove_link);
581
582int __init classes_init(void)
583{
584 class_kset = kset_create_and_add("class", NULL, NULL);
585 if (!class_kset)
586 return -ENOMEM;
587 return 0;
588}
589
590EXPORT_SYMBOL_GPL(class_create_file);
591EXPORT_SYMBOL_GPL(class_remove_file);
592EXPORT_SYMBOL_GPL(class_unregister);
593EXPORT_SYMBOL_GPL(class_destroy);
594
595EXPORT_SYMBOL_GPL(class_interface_register);
596EXPORT_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);