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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/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);