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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_ns(struct class *cls, const struct class_attribute *attr,
90 const void *ns)
91{
92 int error;
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 int add_class_attrs(struct class *cls)
122{
123 int i;
124 int error = 0;
125
126 if (cls->class_attrs) {
127 for (i = 0; cls->class_attrs[i].attr.name; i++) {
128 error = class_create_file(cls, &cls->class_attrs[i]);
129 if (error)
130 goto error;
131 }
132 }
133done:
134 return error;
135error:
136 while (--i >= 0)
137 class_remove_file(cls, &cls->class_attrs[i]);
138 goto done;
139}
140
141static void remove_class_attrs(struct class *cls)
142{
143 int i;
144
145 if (cls->class_attrs) {
146 for (i = 0; cls->class_attrs[i].attr.name; i++)
147 class_remove_file(cls, &cls->class_attrs[i]);
148 }
149}
150
151static void klist_class_dev_get(struct klist_node *n)
152{
153 struct device *dev = container_of(n, struct device, knode_class);
154
155 get_device(dev);
156}
157
158static void klist_class_dev_put(struct klist_node *n)
159{
160 struct device *dev = container_of(n, struct device, knode_class);
161
162 put_device(dev);
163}
164
165int __class_register(struct class *cls, struct lock_class_key *key)
166{
167 struct subsys_private *cp;
168 int error;
169
170 pr_debug("device class '%s': registering\n", cls->name);
171
172 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
173 if (!cp)
174 return -ENOMEM;
175 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
176 INIT_LIST_HEAD(&cp->interfaces);
177 kset_init(&cp->glue_dirs);
178 __mutex_init(&cp->mutex, "subsys mutex", key);
179 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
180 if (error) {
181 kfree(cp);
182 return error;
183 }
184
185 /* set the default /sys/dev directory for devices of this class */
186 if (!cls->dev_kobj)
187 cls->dev_kobj = sysfs_dev_char_kobj;
188
189#if defined(CONFIG_BLOCK)
190 /* let the block class directory show up in the root of sysfs */
191 if (!sysfs_deprecated || cls != &block_class)
192 cp->subsys.kobj.kset = class_kset;
193#else
194 cp->subsys.kobj.kset = class_kset;
195#endif
196 cp->subsys.kobj.ktype = &class_ktype;
197 cp->class = cls;
198 cls->p = cp;
199
200 error = kset_register(&cp->subsys);
201 if (error) {
202 kfree(cp);
203 return error;
204 }
205 error = add_class_attrs(class_get(cls));
206 class_put(cls);
207 return error;
208}
209EXPORT_SYMBOL_GPL(__class_register);
210
211void class_unregister(struct class *cls)
212{
213 pr_debug("device class '%s': unregistering\n", cls->name);
214 remove_class_attrs(cls);
215 kset_unregister(&cls->p->subsys);
216}
217
218static void class_create_release(struct class *cls)
219{
220 pr_debug("%s called for %s\n", __func__, cls->name);
221 kfree(cls);
222}
223
224/**
225 * class_create - create a struct class structure
226 * @owner: pointer to the module that is to "own" this struct class
227 * @name: pointer to a string for the name of this class.
228 * @key: the lock_class_key for this class; used by mutex lock debugging
229 *
230 * This is used to create a struct class pointer that can then be used
231 * in calls to device_create().
232 *
233 * Returns &struct class pointer on success, or ERR_PTR() on error.
234 *
235 * Note, the pointer created here is to be destroyed when finished by
236 * making a call to class_destroy().
237 */
238struct class *__class_create(struct module *owner, const char *name,
239 struct lock_class_key *key)
240{
241 struct class *cls;
242 int retval;
243
244 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
245 if (!cls) {
246 retval = -ENOMEM;
247 goto error;
248 }
249
250 cls->name = name;
251 cls->owner = owner;
252 cls->class_release = class_create_release;
253
254 retval = __class_register(cls, key);
255 if (retval)
256 goto error;
257
258 return cls;
259
260error:
261 kfree(cls);
262 return ERR_PTR(retval);
263}
264EXPORT_SYMBOL_GPL(__class_create);
265
266/**
267 * class_destroy - destroys a struct class structure
268 * @cls: pointer to the struct class that is to be destroyed
269 *
270 * Note, the pointer to be destroyed must have been created with a call
271 * to class_create().
272 */
273void class_destroy(struct class *cls)
274{
275 if ((cls == NULL) || (IS_ERR(cls)))
276 return;
277
278 class_unregister(cls);
279}
280
281/**
282 * class_dev_iter_init - initialize class device iterator
283 * @iter: class iterator to initialize
284 * @class: the class we wanna iterate over
285 * @start: the device to start iterating from, if any
286 * @type: device_type of the devices to iterate over, NULL for all
287 *
288 * Initialize class iterator @iter such that it iterates over devices
289 * of @class. If @start is set, the list iteration will start there,
290 * otherwise if it is NULL, the iteration starts at the beginning of
291 * the list.
292 */
293void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
294 struct device *start, const struct device_type *type)
295{
296 struct klist_node *start_knode = NULL;
297
298 if (start)
299 start_knode = &start->knode_class;
300 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
301 iter->type = type;
302}
303EXPORT_SYMBOL_GPL(class_dev_iter_init);
304
305/**
306 * class_dev_iter_next - iterate to the next device
307 * @iter: class iterator to proceed
308 *
309 * Proceed @iter to the next device and return it. Returns NULL if
310 * iteration is complete.
311 *
312 * The returned device is referenced and won't be released till
313 * iterator is proceed to the next device or exited. The caller is
314 * free to do whatever it wants to do with the device including
315 * calling back into class code.
316 */
317struct device *class_dev_iter_next(struct class_dev_iter *iter)
318{
319 struct klist_node *knode;
320 struct device *dev;
321
322 while (1) {
323 knode = klist_next(&iter->ki);
324 if (!knode)
325 return NULL;
326 dev = container_of(knode, struct device, knode_class);
327 if (!iter->type || iter->type == dev->type)
328 return dev;
329 }
330}
331EXPORT_SYMBOL_GPL(class_dev_iter_next);
332
333/**
334 * class_dev_iter_exit - finish iteration
335 * @iter: class iterator to finish
336 *
337 * Finish an iteration. Always call this function after iteration is
338 * complete whether the iteration ran till the end or not.
339 */
340void class_dev_iter_exit(struct class_dev_iter *iter)
341{
342 klist_iter_exit(&iter->ki);
343}
344EXPORT_SYMBOL_GPL(class_dev_iter_exit);
345
346/**
347 * class_for_each_device - device iterator
348 * @class: the class we're iterating
349 * @start: the device to start with in the list, if any.
350 * @data: data for the callback
351 * @fn: function to be called for each device
352 *
353 * Iterate over @class's list of devices, and call @fn for each,
354 * passing it @data. If @start is set, the list iteration will start
355 * there, otherwise if it is NULL, the iteration starts at the
356 * beginning of the list.
357 *
358 * We check the return of @fn each time. If it returns anything
359 * other than 0, we break out and return that value.
360 *
361 * @fn is allowed to do anything including calling back into class
362 * code. There's no locking restriction.
363 */
364int class_for_each_device(struct class *class, struct device *start,
365 void *data, int (*fn)(struct device *, void *))
366{
367 struct class_dev_iter iter;
368 struct device *dev;
369 int error = 0;
370
371 if (!class)
372 return -EINVAL;
373 if (!class->p) {
374 WARN(1, "%s called for class '%s' before it was initialized",
375 __func__, class->name);
376 return -EINVAL;
377 }
378
379 class_dev_iter_init(&iter, class, start, NULL);
380 while ((dev = class_dev_iter_next(&iter))) {
381 error = fn(dev, data);
382 if (error)
383 break;
384 }
385 class_dev_iter_exit(&iter);
386
387 return error;
388}
389EXPORT_SYMBOL_GPL(class_for_each_device);
390
391/**
392 * class_find_device - device iterator for locating a particular device
393 * @class: the class we're iterating
394 * @start: Device to begin with
395 * @data: data for the match function
396 * @match: function to check device
397 *
398 * This is similar to the class_for_each_dev() function above, but it
399 * returns a reference to a device that is 'found' for later use, as
400 * determined by the @match callback.
401 *
402 * The callback should return 0 if the device doesn't match and non-zero
403 * if it does. If the callback returns non-zero, this function will
404 * return to the caller and not iterate over any more devices.
405 *
406 * Note, you will need to drop the reference with put_device() after use.
407 *
408 * @fn is allowed to do anything including calling back into class
409 * code. There's no locking restriction.
410 */
411struct device *class_find_device(struct class *class, struct device *start,
412 const void *data,
413 int (*match)(struct device *, const void *))
414{
415 struct class_dev_iter iter;
416 struct device *dev;
417
418 if (!class)
419 return NULL;
420 if (!class->p) {
421 WARN(1, "%s called for class '%s' before it was initialized",
422 __func__, class->name);
423 return NULL;
424 }
425
426 class_dev_iter_init(&iter, class, start, NULL);
427 while ((dev = class_dev_iter_next(&iter))) {
428 if (match(dev, data)) {
429 get_device(dev);
430 break;
431 }
432 }
433 class_dev_iter_exit(&iter);
434
435 return dev;
436}
437EXPORT_SYMBOL_GPL(class_find_device);
438
439int class_interface_register(struct class_interface *class_intf)
440{
441 struct class *parent;
442 struct class_dev_iter iter;
443 struct device *dev;
444
445 if (!class_intf || !class_intf->class)
446 return -ENODEV;
447
448 parent = class_get(class_intf->class);
449 if (!parent)
450 return -EINVAL;
451
452 mutex_lock(&parent->p->mutex);
453 list_add_tail(&class_intf->node, &parent->p->interfaces);
454 if (class_intf->add_dev) {
455 class_dev_iter_init(&iter, parent, NULL, NULL);
456 while ((dev = class_dev_iter_next(&iter)))
457 class_intf->add_dev(dev, class_intf);
458 class_dev_iter_exit(&iter);
459 }
460 mutex_unlock(&parent->p->mutex);
461
462 return 0;
463}
464
465void class_interface_unregister(struct class_interface *class_intf)
466{
467 struct class *parent = class_intf->class;
468 struct class_dev_iter iter;
469 struct device *dev;
470
471 if (!parent)
472 return;
473
474 mutex_lock(&parent->p->mutex);
475 list_del_init(&class_intf->node);
476 if (class_intf->remove_dev) {
477 class_dev_iter_init(&iter, parent, NULL, NULL);
478 while ((dev = class_dev_iter_next(&iter)))
479 class_intf->remove_dev(dev, class_intf);
480 class_dev_iter_exit(&iter);
481 }
482 mutex_unlock(&parent->p->mutex);
483
484 class_put(parent);
485}
486
487ssize_t show_class_attr_string(struct class *class,
488 struct class_attribute *attr, char *buf)
489{
490 struct class_attribute_string *cs;
491 cs = container_of(attr, struct class_attribute_string, attr);
492 return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
493}
494
495EXPORT_SYMBOL_GPL(show_class_attr_string);
496
497struct class_compat {
498 struct kobject *kobj;
499};
500
501/**
502 * class_compat_register - register a compatibility class
503 * @name: the name of the class
504 *
505 * Compatibility class are meant as a temporary user-space compatibility
506 * workaround when converting a family of class devices to a bus devices.
507 */
508struct class_compat *class_compat_register(const char *name)
509{
510 struct class_compat *cls;
511
512 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
513 if (!cls)
514 return NULL;
515 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
516 if (!cls->kobj) {
517 kfree(cls);
518 return NULL;
519 }
520 return cls;
521}
522EXPORT_SYMBOL_GPL(class_compat_register);
523
524/**
525 * class_compat_unregister - unregister a compatibility class
526 * @cls: the class to unregister
527 */
528void class_compat_unregister(struct class_compat *cls)
529{
530 kobject_put(cls->kobj);
531 kfree(cls);
532}
533EXPORT_SYMBOL_GPL(class_compat_unregister);
534
535/**
536 * class_compat_create_link - create a compatibility class device link to
537 * a bus device
538 * @cls: the compatibility class
539 * @dev: the target bus device
540 * @device_link: an optional device to which a "device" link should be created
541 */
542int class_compat_create_link(struct class_compat *cls, struct device *dev,
543 struct device *device_link)
544{
545 int error;
546
547 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
548 if (error)
549 return error;
550
551 /*
552 * Optionally add a "device" link (typically to the parent), as a
553 * class device would have one and we want to provide as much
554 * backwards compatibility as possible.
555 */
556 if (device_link) {
557 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
558 "device");
559 if (error)
560 sysfs_remove_link(cls->kobj, dev_name(dev));
561 }
562
563 return error;
564}
565EXPORT_SYMBOL_GPL(class_compat_create_link);
566
567/**
568 * class_compat_remove_link - remove a compatibility class device link to
569 * a bus device
570 * @cls: the compatibility class
571 * @dev: the target bus device
572 * @device_link: an optional device to which a "device" link was previously
573 * created
574 */
575void class_compat_remove_link(struct class_compat *cls, struct device *dev,
576 struct device *device_link)
577{
578 if (device_link)
579 sysfs_remove_link(&dev->kobj, "device");
580 sysfs_remove_link(cls->kobj, dev_name(dev));
581}
582EXPORT_SYMBOL_GPL(class_compat_remove_link);
583
584int __init classes_init(void)
585{
586 class_kset = kset_create_and_add("class", NULL, NULL);
587 if (!class_kset)
588 return -ENOMEM;
589 return 0;
590}
591
592EXPORT_SYMBOL_GPL(class_create_file_ns);
593EXPORT_SYMBOL_GPL(class_remove_file_ns);
594EXPORT_SYMBOL_GPL(class_unregister);
595EXPORT_SYMBOL_GPL(class_destroy);
596
597EXPORT_SYMBOL_GPL(class_interface_register);
598EXPORT_SYMBOL_GPL(class_interface_unregister);
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_ns(struct class *cls, const struct class_attribute *attr,
90 const void *ns)
91{
92 int error;
93
94 if (cls)
95 error = sysfs_create_file_ns(&cls->p->subsys.kobj,
96 &attr->attr, ns);
97 else
98 error = -EINVAL;
99 return error;
100}
101
102void class_remove_file_ns(struct class *cls, const struct class_attribute *attr,
103 const void *ns)
104{
105 if (cls)
106 sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns);
107}
108
109static struct class *class_get(struct class *cls)
110{
111 if (cls)
112 kset_get(&cls->p->subsys);
113 return cls;
114}
115
116static void class_put(struct class *cls)
117{
118 if (cls)
119 kset_put(&cls->p->subsys);
120}
121
122static int add_class_attrs(struct class *cls)
123{
124 int i;
125 int error = 0;
126
127 if (cls->class_attrs) {
128 for (i = 0; cls->class_attrs[i].attr.name; i++) {
129 error = class_create_file(cls, &cls->class_attrs[i]);
130 if (error)
131 goto error;
132 }
133 }
134done:
135 return error;
136error:
137 while (--i >= 0)
138 class_remove_file(cls, &cls->class_attrs[i]);
139 goto done;
140}
141
142static void remove_class_attrs(struct class *cls)
143{
144 int i;
145
146 if (cls->class_attrs) {
147 for (i = 0; cls->class_attrs[i].attr.name; i++)
148 class_remove_file(cls, &cls->class_attrs[i]);
149 }
150}
151
152static void klist_class_dev_get(struct klist_node *n)
153{
154 struct device *dev = container_of(n, struct device, knode_class);
155
156 get_device(dev);
157}
158
159static void klist_class_dev_put(struct klist_node *n)
160{
161 struct device *dev = container_of(n, struct device, knode_class);
162
163 put_device(dev);
164}
165
166int __class_register(struct class *cls, struct lock_class_key *key)
167{
168 struct subsys_private *cp;
169 int error;
170
171 pr_debug("device class '%s': registering\n", cls->name);
172
173 cp = kzalloc(sizeof(*cp), GFP_KERNEL);
174 if (!cp)
175 return -ENOMEM;
176 klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put);
177 INIT_LIST_HEAD(&cp->interfaces);
178 kset_init(&cp->glue_dirs);
179 __mutex_init(&cp->mutex, "subsys mutex", key);
180 error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name);
181 if (error) {
182 kfree(cp);
183 return error;
184 }
185
186 /* set the default /sys/dev directory for devices of this class */
187 if (!cls->dev_kobj)
188 cls->dev_kobj = sysfs_dev_char_kobj;
189
190#if defined(CONFIG_BLOCK)
191 /* let the block class directory show up in the root of sysfs */
192 if (!sysfs_deprecated || cls != &block_class)
193 cp->subsys.kobj.kset = class_kset;
194#else
195 cp->subsys.kobj.kset = class_kset;
196#endif
197 cp->subsys.kobj.ktype = &class_ktype;
198 cp->class = cls;
199 cls->p = cp;
200
201 error = kset_register(&cp->subsys);
202 if (error) {
203 kfree(cp);
204 return error;
205 }
206 error = add_class_attrs(class_get(cls));
207 class_put(cls);
208 return error;
209}
210EXPORT_SYMBOL_GPL(__class_register);
211
212void class_unregister(struct class *cls)
213{
214 pr_debug("device class '%s': unregistering\n", cls->name);
215 remove_class_attrs(cls);
216 kset_unregister(&cls->p->subsys);
217}
218
219static void class_create_release(struct class *cls)
220{
221 pr_debug("%s called for %s\n", __func__, cls->name);
222 kfree(cls);
223}
224
225/**
226 * class_create - create a struct class structure
227 * @owner: pointer to the module that is to "own" this struct class
228 * @name: pointer to a string for the name of this class.
229 * @key: the lock_class_key for this class; used by mutex lock debugging
230 *
231 * This is used to create a struct class pointer that can then be used
232 * in calls to device_create().
233 *
234 * Returns &struct class pointer on success, or ERR_PTR() on error.
235 *
236 * Note, the pointer created here is to be destroyed when finished by
237 * making a call to class_destroy().
238 */
239struct class *__class_create(struct module *owner, const char *name,
240 struct lock_class_key *key)
241{
242 struct class *cls;
243 int retval;
244
245 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
246 if (!cls) {
247 retval = -ENOMEM;
248 goto error;
249 }
250
251 cls->name = name;
252 cls->owner = owner;
253 cls->class_release = class_create_release;
254
255 retval = __class_register(cls, key);
256 if (retval)
257 goto error;
258
259 return cls;
260
261error:
262 kfree(cls);
263 return ERR_PTR(retval);
264}
265EXPORT_SYMBOL_GPL(__class_create);
266
267/**
268 * class_destroy - destroys a struct class structure
269 * @cls: pointer to the struct class that is to be destroyed
270 *
271 * Note, the pointer to be destroyed must have been created with a call
272 * to class_create().
273 */
274void class_destroy(struct class *cls)
275{
276 if ((cls == NULL) || (IS_ERR(cls)))
277 return;
278
279 class_unregister(cls);
280}
281
282/**
283 * class_dev_iter_init - initialize class device iterator
284 * @iter: class iterator to initialize
285 * @class: the class we wanna iterate over
286 * @start: the device to start iterating from, if any
287 * @type: device_type of the devices to iterate over, NULL for all
288 *
289 * Initialize class iterator @iter such that it iterates over devices
290 * of @class. If @start is set, the list iteration will start there,
291 * otherwise if it is NULL, the iteration starts at the beginning of
292 * the list.
293 */
294void class_dev_iter_init(struct class_dev_iter *iter, struct class *class,
295 struct device *start, const struct device_type *type)
296{
297 struct klist_node *start_knode = NULL;
298
299 if (start)
300 start_knode = &start->knode_class;
301 klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode);
302 iter->type = type;
303}
304EXPORT_SYMBOL_GPL(class_dev_iter_init);
305
306/**
307 * class_dev_iter_next - iterate to the next device
308 * @iter: class iterator to proceed
309 *
310 * Proceed @iter to the next device and return it. Returns NULL if
311 * iteration is complete.
312 *
313 * The returned device is referenced and won't be released till
314 * iterator is proceed to the next device or exited. The caller is
315 * free to do whatever it wants to do with the device including
316 * calling back into class code.
317 */
318struct device *class_dev_iter_next(struct class_dev_iter *iter)
319{
320 struct klist_node *knode;
321 struct device *dev;
322
323 while (1) {
324 knode = klist_next(&iter->ki);
325 if (!knode)
326 return NULL;
327 dev = container_of(knode, struct device, knode_class);
328 if (!iter->type || iter->type == dev->type)
329 return dev;
330 }
331}
332EXPORT_SYMBOL_GPL(class_dev_iter_next);
333
334/**
335 * class_dev_iter_exit - finish iteration
336 * @iter: class iterator to finish
337 *
338 * Finish an iteration. Always call this function after iteration is
339 * complete whether the iteration ran till the end or not.
340 */
341void class_dev_iter_exit(struct class_dev_iter *iter)
342{
343 klist_iter_exit(&iter->ki);
344}
345EXPORT_SYMBOL_GPL(class_dev_iter_exit);
346
347/**
348 * class_for_each_device - device iterator
349 * @class: the class we're iterating
350 * @start: the device to start with in the list, if any.
351 * @data: data for the callback
352 * @fn: function to be called for each device
353 *
354 * Iterate over @class's list of devices, and call @fn for each,
355 * passing it @data. If @start is set, the list iteration will start
356 * there, otherwise if it is NULL, the iteration starts at the
357 * beginning of the list.
358 *
359 * We check the return of @fn each time. If it returns anything
360 * other than 0, we break out and return that value.
361 *
362 * @fn is allowed to do anything including calling back into class
363 * code. There's no locking restriction.
364 */
365int class_for_each_device(struct class *class, struct device *start,
366 void *data, int (*fn)(struct device *, void *))
367{
368 struct class_dev_iter iter;
369 struct device *dev;
370 int error = 0;
371
372 if (!class)
373 return -EINVAL;
374 if (!class->p) {
375 WARN(1, "%s called for class '%s' before it was initialized",
376 __func__, class->name);
377 return -EINVAL;
378 }
379
380 class_dev_iter_init(&iter, class, start, NULL);
381 while ((dev = class_dev_iter_next(&iter))) {
382 error = fn(dev, data);
383 if (error)
384 break;
385 }
386 class_dev_iter_exit(&iter);
387
388 return error;
389}
390EXPORT_SYMBOL_GPL(class_for_each_device);
391
392/**
393 * class_find_device - device iterator for locating a particular device
394 * @class: the class we're iterating
395 * @start: Device to begin with
396 * @data: data for the match function
397 * @match: function to check device
398 *
399 * This is similar to the class_for_each_dev() function above, but it
400 * returns a reference to a device that is 'found' for later use, as
401 * determined by the @match callback.
402 *
403 * The callback should return 0 if the device doesn't match and non-zero
404 * if it does. If the callback returns non-zero, this function will
405 * return to the caller and not iterate over any more devices.
406 *
407 * Note, you will need to drop the reference with put_device() after use.
408 *
409 * @match is allowed to do anything including calling back into class
410 * code. There's no locking restriction.
411 */
412struct device *class_find_device(struct class *class, struct device *start,
413 const void *data,
414 int (*match)(struct device *, const void *))
415{
416 struct class_dev_iter iter;
417 struct device *dev;
418
419 if (!class)
420 return NULL;
421 if (!class->p) {
422 WARN(1, "%s called for class '%s' before it was initialized",
423 __func__, class->name);
424 return NULL;
425 }
426
427 class_dev_iter_init(&iter, class, start, NULL);
428 while ((dev = class_dev_iter_next(&iter))) {
429 if (match(dev, data)) {
430 get_device(dev);
431 break;
432 }
433 }
434 class_dev_iter_exit(&iter);
435
436 return dev;
437}
438EXPORT_SYMBOL_GPL(class_find_device);
439
440int class_interface_register(struct class_interface *class_intf)
441{
442 struct class *parent;
443 struct class_dev_iter iter;
444 struct device *dev;
445
446 if (!class_intf || !class_intf->class)
447 return -ENODEV;
448
449 parent = class_get(class_intf->class);
450 if (!parent)
451 return -EINVAL;
452
453 mutex_lock(&parent->p->mutex);
454 list_add_tail(&class_intf->node, &parent->p->interfaces);
455 if (class_intf->add_dev) {
456 class_dev_iter_init(&iter, parent, NULL, NULL);
457 while ((dev = class_dev_iter_next(&iter)))
458 class_intf->add_dev(dev, class_intf);
459 class_dev_iter_exit(&iter);
460 }
461 mutex_unlock(&parent->p->mutex);
462
463 return 0;
464}
465
466void class_interface_unregister(struct class_interface *class_intf)
467{
468 struct class *parent = class_intf->class;
469 struct class_dev_iter iter;
470 struct device *dev;
471
472 if (!parent)
473 return;
474
475 mutex_lock(&parent->p->mutex);
476 list_del_init(&class_intf->node);
477 if (class_intf->remove_dev) {
478 class_dev_iter_init(&iter, parent, NULL, NULL);
479 while ((dev = class_dev_iter_next(&iter)))
480 class_intf->remove_dev(dev, class_intf);
481 class_dev_iter_exit(&iter);
482 }
483 mutex_unlock(&parent->p->mutex);
484
485 class_put(parent);
486}
487
488ssize_t show_class_attr_string(struct class *class,
489 struct class_attribute *attr, char *buf)
490{
491 struct class_attribute_string *cs;
492
493 cs = container_of(attr, struct class_attribute_string, attr);
494 return snprintf(buf, PAGE_SIZE, "%s\n", cs->str);
495}
496
497EXPORT_SYMBOL_GPL(show_class_attr_string);
498
499struct class_compat {
500 struct kobject *kobj;
501};
502
503/**
504 * class_compat_register - register a compatibility class
505 * @name: the name of the class
506 *
507 * Compatibility class are meant as a temporary user-space compatibility
508 * workaround when converting a family of class devices to a bus devices.
509 */
510struct class_compat *class_compat_register(const char *name)
511{
512 struct class_compat *cls;
513
514 cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL);
515 if (!cls)
516 return NULL;
517 cls->kobj = kobject_create_and_add(name, &class_kset->kobj);
518 if (!cls->kobj) {
519 kfree(cls);
520 return NULL;
521 }
522 return cls;
523}
524EXPORT_SYMBOL_GPL(class_compat_register);
525
526/**
527 * class_compat_unregister - unregister a compatibility class
528 * @cls: the class to unregister
529 */
530void class_compat_unregister(struct class_compat *cls)
531{
532 kobject_put(cls->kobj);
533 kfree(cls);
534}
535EXPORT_SYMBOL_GPL(class_compat_unregister);
536
537/**
538 * class_compat_create_link - create a compatibility class device link to
539 * a bus device
540 * @cls: the compatibility class
541 * @dev: the target bus device
542 * @device_link: an optional device to which a "device" link should be created
543 */
544int class_compat_create_link(struct class_compat *cls, struct device *dev,
545 struct device *device_link)
546{
547 int error;
548
549 error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev));
550 if (error)
551 return error;
552
553 /*
554 * Optionally add a "device" link (typically to the parent), as a
555 * class device would have one and we want to provide as much
556 * backwards compatibility as possible.
557 */
558 if (device_link) {
559 error = sysfs_create_link(&dev->kobj, &device_link->kobj,
560 "device");
561 if (error)
562 sysfs_remove_link(cls->kobj, dev_name(dev));
563 }
564
565 return error;
566}
567EXPORT_SYMBOL_GPL(class_compat_create_link);
568
569/**
570 * class_compat_remove_link - remove a compatibility class device link to
571 * a bus device
572 * @cls: the compatibility class
573 * @dev: the target bus device
574 * @device_link: an optional device to which a "device" link was previously
575 * created
576 */
577void class_compat_remove_link(struct class_compat *cls, struct device *dev,
578 struct device *device_link)
579{
580 if (device_link)
581 sysfs_remove_link(&dev->kobj, "device");
582 sysfs_remove_link(cls->kobj, dev_name(dev));
583}
584EXPORT_SYMBOL_GPL(class_compat_remove_link);
585
586int __init classes_init(void)
587{
588 class_kset = kset_create_and_add("class", NULL, NULL);
589 if (!class_kset)
590 return -ENOMEM;
591 return 0;
592}
593
594EXPORT_SYMBOL_GPL(class_create_file_ns);
595EXPORT_SYMBOL_GPL(class_remove_file_ns);
596EXPORT_SYMBOL_GPL(class_unregister);
597EXPORT_SYMBOL_GPL(class_destroy);
598
599EXPORT_SYMBOL_GPL(class_interface_register);
600EXPORT_SYMBOL_GPL(class_interface_unregister);