Commit | Line | Data |
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989d42e8 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
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. | |
1da177e4 LT |
9 | */ |
10 | ||
a8ae6085 | 11 | #include <linux/device/class.h> |
1da177e4 LT |
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> | |
e9ba6365 | 17 | #include <linux/err.h> |
4e57b681 | 18 | #include <linux/slab.h> |
edfaa7c3 | 19 | #include <linux/genhd.h> |
f75b1c60 | 20 | #include <linux/mutex.h> |
1da177e4 LT |
21 | #include "base.h" |
22 | ||
23 | #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr) | |
1da177e4 | 24 | |
4a3ad20c GKH |
25 | static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr, |
26 | char *buf) | |
1da177e4 | 27 | { |
4a3ad20c | 28 | struct class_attribute *class_attr = to_class_attr(attr); |
6b6e39a6 | 29 | struct subsys_private *cp = to_subsys_private(kobj); |
4a0c20bf | 30 | ssize_t ret = -EIO; |
1da177e4 LT |
31 | |
32 | if (class_attr->show) | |
28812fe1 | 33 | ret = class_attr->show(cp->class, class_attr, buf); |
1da177e4 LT |
34 | return ret; |
35 | } | |
36 | ||
4a3ad20c GKH |
37 | static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr, |
38 | const char *buf, size_t count) | |
1da177e4 | 39 | { |
4a3ad20c | 40 | struct class_attribute *class_attr = to_class_attr(attr); |
6b6e39a6 | 41 | struct subsys_private *cp = to_subsys_private(kobj); |
4a0c20bf | 42 | ssize_t ret = -EIO; |
1da177e4 LT |
43 | |
44 | if (class_attr->store) | |
28812fe1 | 45 | ret = class_attr->store(cp->class, class_attr, buf, count); |
1da177e4 LT |
46 | return ret; |
47 | } | |
48 | ||
4a3ad20c | 49 | static void class_release(struct kobject *kobj) |
1da177e4 | 50 | { |
6b6e39a6 | 51 | struct subsys_private *cp = to_subsys_private(kobj); |
7c71448b | 52 | struct class *class = cp->class; |
1da177e4 LT |
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); | |
18d19c96 LP |
61 | |
62 | kfree(cp); | |
1da177e4 LT |
63 | } |
64 | ||
bc451f20 EB |
65 | static const struct kobj_ns_type_operations *class_child_ns_type(struct kobject *kobj) |
66 | { | |
6b6e39a6 | 67 | struct subsys_private *cp = to_subsys_private(kobj); |
bc451f20 EB |
68 | struct class *class = cp->class; |
69 | ||
70 | return class->ns_type; | |
71 | } | |
72 | ||
52cf25d0 | 73 | static const struct sysfs_ops class_sysfs_ops = { |
672d82c1 EB |
74 | .show = class_attr_show, |
75 | .store = class_attr_store, | |
1da177e4 LT |
76 | }; |
77 | ||
adc56808 | 78 | static struct kobj_type class_ktype = { |
1da177e4 LT |
79 | .sysfs_ops = &class_sysfs_ops, |
80 | .release = class_release, | |
bc451f20 | 81 | .child_ns_type = class_child_ns_type, |
1da177e4 LT |
82 | }; |
83 | ||
6b6e39a6 | 84 | /* Hotplug events for classes go to the class subsys */ |
443dbf90 | 85 | static struct kset *class_kset; |
1da177e4 LT |
86 | |
87 | ||
58292cbe TH |
88 | int class_create_file_ns(struct class *cls, const struct class_attribute *attr, |
89 | const void *ns) | |
1da177e4 LT |
90 | { |
91 | int error; | |
d34898de | 92 | |
4a3ad20c | 93 | if (cls) |
58292cbe TH |
94 | error = sysfs_create_file_ns(&cls->p->subsys.kobj, |
95 | &attr->attr, ns); | |
4a3ad20c | 96 | else |
1da177e4 LT |
97 | error = -EINVAL; |
98 | return error; | |
99 | } | |
100 | ||
58292cbe TH |
101 | void class_remove_file_ns(struct class *cls, const struct class_attribute *attr, |
102 | const void *ns) | |
1da177e4 LT |
103 | { |
104 | if (cls) | |
58292cbe | 105 | sysfs_remove_file_ns(&cls->p->subsys.kobj, &attr->attr, ns); |
1da177e4 LT |
106 | } |
107 | ||
1740757e | 108 | static struct class *class_get(struct class *cls) |
1da177e4 LT |
109 | { |
110 | if (cls) | |
6b6e39a6 | 111 | kset_get(&cls->p->subsys); |
7c71448b | 112 | return cls; |
1da177e4 LT |
113 | } |
114 | ||
4a3ad20c | 115 | static void class_put(struct class *cls) |
1da177e4 | 116 | { |
51d172d5 | 117 | if (cls) |
6b6e39a6 | 118 | kset_put(&cls->p->subsys); |
1da177e4 LT |
119 | } |
120 | ||
570d0200 WY |
121 | static 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 | ||
5a3ceb86 TH |
127 | static void klist_class_dev_get(struct klist_node *n) |
128 | { | |
570d0200 | 129 | struct device *dev = klist_class_to_dev(n); |
5a3ceb86 TH |
130 | |
131 | get_device(dev); | |
132 | } | |
133 | ||
134 | static void klist_class_dev_put(struct klist_node *n) | |
135 | { | |
570d0200 | 136 | struct device *dev = klist_class_to_dev(n); |
5a3ceb86 TH |
137 | |
138 | put_device(dev); | |
139 | } | |
140 | ||
ced6473e GKH |
141 | static 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 | ||
147 | static 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 | ||
d2a3b914 | 153 | int __class_register(struct class *cls, struct lock_class_key *key) |
1da177e4 | 154 | { |
6b6e39a6 | 155 | struct subsys_private *cp; |
1da177e4 LT |
156 | int error; |
157 | ||
158 | pr_debug("device class '%s': registering\n", cls->name); | |
159 | ||
7c71448b GKH |
160 | cp = kzalloc(sizeof(*cp), GFP_KERNEL); |
161 | if (!cp) | |
162 | return -ENOMEM; | |
6b6e39a6 | 163 | klist_init(&cp->klist_devices, klist_class_dev_get, klist_class_dev_put); |
ca22e56d | 164 | INIT_LIST_HEAD(&cp->interfaces); |
6b6e39a6 | 165 | kset_init(&cp->glue_dirs); |
ca22e56d | 166 | __mutex_init(&cp->mutex, "subsys mutex", key); |
6b6e39a6 | 167 | error = kobject_set_name(&cp->subsys.kobj, "%s", cls->name); |
7c71448b GKH |
168 | if (error) { |
169 | kfree(cp); | |
1da177e4 | 170 | return error; |
7c71448b | 171 | } |
1da177e4 | 172 | |
e105b8bf DW |
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 | ||
e52eec13 | 177 | #if defined(CONFIG_BLOCK) |
edfaa7c3 | 178 | /* let the block class directory show up in the root of sysfs */ |
e52eec13 | 179 | if (!sysfs_deprecated || cls != &block_class) |
6b6e39a6 | 180 | cp->subsys.kobj.kset = class_kset; |
edfaa7c3 | 181 | #else |
6b6e39a6 | 182 | cp->subsys.kobj.kset = class_kset; |
edfaa7c3 | 183 | #endif |
6b6e39a6 | 184 | cp->subsys.kobj.ktype = &class_ktype; |
7c71448b GKH |
185 | cp->class = cls; |
186 | cls->p = cp; | |
1da177e4 | 187 | |
6b6e39a6 | 188 | error = kset_register(&cp->subsys); |
7c71448b GKH |
189 | if (error) { |
190 | kfree(cp); | |
191 | return error; | |
1da177e4 | 192 | } |
ced6473e GKH |
193 | error = class_add_groups(class_get(cls), cls->class_groups); |
194 | class_put(cls); | |
1da177e4 LT |
195 | return error; |
196 | } | |
d2a3b914 | 197 | EXPORT_SYMBOL_GPL(__class_register); |
1da177e4 | 198 | |
4a3ad20c | 199 | void class_unregister(struct class *cls) |
1da177e4 LT |
200 | { |
201 | pr_debug("device class '%s': unregistering\n", cls->name); | |
ced6473e | 202 | class_remove_groups(cls, cls->class_groups); |
6b6e39a6 | 203 | kset_unregister(&cls->p->subsys); |
1da177e4 LT |
204 | } |
205 | ||
e9ba6365 | 206 | static void class_create_release(struct class *cls) |
207 | { | |
2b3a302a | 208 | pr_debug("%s called for %s\n", __func__, cls->name); |
e9ba6365 | 209 | kfree(cls); |
210 | } | |
211 | ||
2fc68447 | 212 | /** |
33c0c9bd | 213 | * __class_create - create a struct class structure |
2fc68447 | 214 | * @owner: pointer to the module that is to "own" this struct class |
215 | * @name: pointer to a string for the name of this class. | |
0e241ffd | 216 | * @key: the lock_class_key for this class; used by mutex lock debugging |
2fc68447 | 217 | * |
218 | * This is used to create a struct class pointer that can then be used | |
c3b19ff0 | 219 | * in calls to device_create(). |
2fc68447 | 220 | * |
f0eae0ed JN |
221 | * Returns &struct class pointer on success, or ERR_PTR() on error. |
222 | * | |
2fc68447 | 223 | * Note, the pointer created here is to be destroyed when finished by |
224 | * making a call to class_destroy(). | |
225 | */ | |
d2a3b914 MW |
226 | struct class *__class_create(struct module *owner, const char *name, |
227 | struct lock_class_key *key) | |
e9ba6365 | 228 | { |
229 | struct class *cls; | |
230 | int retval; | |
231 | ||
4aed0644 | 232 | cls = kzalloc(sizeof(*cls), GFP_KERNEL); |
e9ba6365 | 233 | if (!cls) { |
234 | retval = -ENOMEM; | |
235 | goto error; | |
236 | } | |
e9ba6365 | 237 | |
238 | cls->name = name; | |
239 | cls->owner = owner; | |
240 | cls->class_release = class_create_release; | |
e9ba6365 | 241 | |
d2a3b914 | 242 | retval = __class_register(cls, key); |
e9ba6365 | 243 | if (retval) |
244 | goto error; | |
245 | ||
246 | return cls; | |
247 | ||
248 | error: | |
249 | kfree(cls); | |
250 | return ERR_PTR(retval); | |
251 | } | |
d2a3b914 | 252 | EXPORT_SYMBOL_GPL(__class_create); |
e9ba6365 | 253 | |
2fc68447 | 254 | /** |
255 | * class_destroy - destroys a struct class structure | |
92a0f861 | 256 | * @cls: pointer to the struct class that is to be destroyed |
2fc68447 | 257 | * |
258 | * Note, the pointer to be destroyed must have been created with a call | |
259 | * to class_create(). | |
260 | */ | |
e9ba6365 | 261 | void class_destroy(struct class *cls) |
262 | { | |
263 | if ((cls == NULL) || (IS_ERR(cls))) | |
264 | return; | |
265 | ||
266 | class_unregister(cls); | |
267 | } | |
1da177e4 | 268 | |
5a3ceb86 TH |
269 | /** |
270 | * class_dev_iter_init - initialize class device iterator | |
271 | * @iter: class iterator to initialize | |
272 | * @class: the class we wanna iterate over | |
273 | * @start: the device to start iterating from, if any | |
274 | * @type: device_type of the devices to iterate over, NULL for all | |
275 | * | |
276 | * Initialize class iterator @iter such that it iterates over devices | |
277 | * of @class. If @start is set, the list iteration will start there, | |
278 | * otherwise if it is NULL, the iteration starts at the beginning of | |
279 | * the list. | |
280 | */ | |
281 | void class_dev_iter_init(struct class_dev_iter *iter, struct class *class, | |
282 | struct device *start, const struct device_type *type) | |
283 | { | |
284 | struct klist_node *start_knode = NULL; | |
285 | ||
286 | if (start) | |
570d0200 | 287 | start_knode = &start->p->knode_class; |
6b6e39a6 | 288 | klist_iter_init_node(&class->p->klist_devices, &iter->ki, start_knode); |
5a3ceb86 TH |
289 | iter->type = type; |
290 | } | |
291 | EXPORT_SYMBOL_GPL(class_dev_iter_init); | |
292 | ||
293 | /** | |
294 | * class_dev_iter_next - iterate to the next device | |
295 | * @iter: class iterator to proceed | |
296 | * | |
297 | * Proceed @iter to the next device and return it. Returns NULL if | |
298 | * iteration is complete. | |
299 | * | |
300 | * The returned device is referenced and won't be released till | |
301 | * iterator is proceed to the next device or exited. The caller is | |
302 | * free to do whatever it wants to do with the device including | |
303 | * calling back into class code. | |
304 | */ | |
305 | struct device *class_dev_iter_next(struct class_dev_iter *iter) | |
306 | { | |
307 | struct klist_node *knode; | |
308 | struct device *dev; | |
309 | ||
310 | while (1) { | |
311 | knode = klist_next(&iter->ki); | |
312 | if (!knode) | |
313 | return NULL; | |
570d0200 | 314 | dev = klist_class_to_dev(knode); |
5a3ceb86 TH |
315 | if (!iter->type || iter->type == dev->type) |
316 | return dev; | |
317 | } | |
318 | } | |
319 | EXPORT_SYMBOL_GPL(class_dev_iter_next); | |
320 | ||
321 | /** | |
322 | * class_dev_iter_exit - finish iteration | |
323 | * @iter: class iterator to finish | |
324 | * | |
325 | * Finish an iteration. Always call this function after iteration is | |
326 | * complete whether the iteration ran till the end or not. | |
327 | */ | |
328 | void class_dev_iter_exit(struct class_dev_iter *iter) | |
329 | { | |
330 | klist_iter_exit(&iter->ki); | |
331 | } | |
332 | EXPORT_SYMBOL_GPL(class_dev_iter_exit); | |
333 | ||
fd04897b DY |
334 | /** |
335 | * class_for_each_device - device iterator | |
336 | * @class: the class we're iterating | |
93562b53 | 337 | * @start: the device to start with in the list, if any. |
fd04897b DY |
338 | * @data: data for the callback |
339 | * @fn: function to be called for each device | |
340 | * | |
341 | * Iterate over @class's list of devices, and call @fn for each, | |
93562b53 GKH |
342 | * passing it @data. If @start is set, the list iteration will start |
343 | * there, otherwise if it is NULL, the iteration starts at the | |
344 | * beginning of the list. | |
fd04897b DY |
345 | * |
346 | * We check the return of @fn each time. If it returns anything | |
347 | * other than 0, we break out and return that value. | |
348 | * | |
5a3ceb86 TH |
349 | * @fn is allowed to do anything including calling back into class |
350 | * code. There's no locking restriction. | |
fd04897b | 351 | */ |
93562b53 GKH |
352 | int class_for_each_device(struct class *class, struct device *start, |
353 | void *data, int (*fn)(struct device *, void *)) | |
fd04897b | 354 | { |
5a3ceb86 | 355 | struct class_dev_iter iter; |
fd04897b DY |
356 | struct device *dev; |
357 | int error = 0; | |
358 | ||
359 | if (!class) | |
360 | return -EINVAL; | |
7c225035 DB |
361 | if (!class->p) { |
362 | WARN(1, "%s called for class '%s' before it was initialized", | |
363 | __func__, class->name); | |
364 | return -EINVAL; | |
365 | } | |
366 | ||
5a3ceb86 TH |
367 | class_dev_iter_init(&iter, class, start, NULL); |
368 | while ((dev = class_dev_iter_next(&iter))) { | |
93562b53 | 369 | error = fn(dev, data); |
fd04897b DY |
370 | if (error) |
371 | break; | |
372 | } | |
5a3ceb86 | 373 | class_dev_iter_exit(&iter); |
fd04897b DY |
374 | |
375 | return error; | |
376 | } | |
377 | EXPORT_SYMBOL_GPL(class_for_each_device); | |
378 | ||
379 | /** | |
380 | * class_find_device - device iterator for locating a particular device | |
381 | * @class: the class we're iterating | |
695794ae | 382 | * @start: Device to begin with |
fd04897b DY |
383 | * @data: data for the match function |
384 | * @match: function to check device | |
385 | * | |
386 | * This is similar to the class_for_each_dev() function above, but it | |
387 | * returns a reference to a device that is 'found' for later use, as | |
388 | * determined by the @match callback. | |
389 | * | |
390 | * The callback should return 0 if the device doesn't match and non-zero | |
391 | * if it does. If the callback returns non-zero, this function will | |
392 | * return to the caller and not iterate over any more devices. | |
a63ca8f6 | 393 | * |
fd04897b DY |
394 | * Note, you will need to drop the reference with put_device() after use. |
395 | * | |
12077754 | 396 | * @match is allowed to do anything including calling back into class |
5a3ceb86 | 397 | * code. There's no locking restriction. |
fd04897b | 398 | */ |
695794ae | 399 | struct device *class_find_device(struct class *class, struct device *start, |
9f3b795a MM |
400 | const void *data, |
401 | int (*match)(struct device *, const void *)) | |
fd04897b | 402 | { |
5a3ceb86 | 403 | struct class_dev_iter iter; |
fd04897b | 404 | struct device *dev; |
fd04897b DY |
405 | |
406 | if (!class) | |
407 | return NULL; | |
7c225035 DB |
408 | if (!class->p) { |
409 | WARN(1, "%s called for class '%s' before it was initialized", | |
410 | __func__, class->name); | |
411 | return NULL; | |
412 | } | |
fd04897b | 413 | |
5a3ceb86 TH |
414 | class_dev_iter_init(&iter, class, start, NULL); |
415 | while ((dev = class_dev_iter_next(&iter))) { | |
695794ae | 416 | if (match(dev, data)) { |
5a3ceb86 | 417 | get_device(dev); |
fd04897b | 418 | break; |
5a3ceb86 | 419 | } |
fd04897b | 420 | } |
5a3ceb86 | 421 | class_dev_iter_exit(&iter); |
fd04897b | 422 | |
5a3ceb86 | 423 | return dev; |
fd04897b DY |
424 | } |
425 | EXPORT_SYMBOL_GPL(class_find_device); | |
426 | ||
1da177e4 LT |
427 | int class_interface_register(struct class_interface *class_intf) |
428 | { | |
429 | struct class *parent; | |
5a3ceb86 | 430 | struct class_dev_iter iter; |
c47ed219 | 431 | struct device *dev; |
1da177e4 LT |
432 | |
433 | if (!class_intf || !class_intf->class) | |
434 | return -ENODEV; | |
435 | ||
436 | parent = class_get(class_intf->class); | |
437 | if (!parent) | |
438 | return -EINVAL; | |
439 | ||
ca22e56d KS |
440 | mutex_lock(&parent->p->mutex); |
441 | list_add_tail(&class_intf->node, &parent->p->interfaces); | |
c47ed219 | 442 | if (class_intf->add_dev) { |
5a3ceb86 TH |
443 | class_dev_iter_init(&iter, parent, NULL, NULL); |
444 | while ((dev = class_dev_iter_next(&iter))) | |
c47ed219 | 445 | class_intf->add_dev(dev, class_intf); |
5a3ceb86 | 446 | class_dev_iter_exit(&iter); |
c47ed219 | 447 | } |
ca22e56d | 448 | mutex_unlock(&parent->p->mutex); |
1da177e4 LT |
449 | |
450 | return 0; | |
451 | } | |
452 | ||
453 | void class_interface_unregister(struct class_interface *class_intf) | |
454 | { | |
4a3ad20c | 455 | struct class *parent = class_intf->class; |
5a3ceb86 | 456 | struct class_dev_iter iter; |
c47ed219 | 457 | struct device *dev; |
1da177e4 LT |
458 | |
459 | if (!parent) | |
460 | return; | |
461 | ||
ca22e56d | 462 | mutex_lock(&parent->p->mutex); |
1da177e4 | 463 | list_del_init(&class_intf->node); |
c47ed219 | 464 | if (class_intf->remove_dev) { |
5a3ceb86 TH |
465 | class_dev_iter_init(&iter, parent, NULL, NULL); |
466 | while ((dev = class_dev_iter_next(&iter))) | |
c47ed219 | 467 | class_intf->remove_dev(dev, class_intf); |
5a3ceb86 | 468 | class_dev_iter_exit(&iter); |
c47ed219 | 469 | } |
ca22e56d | 470 | mutex_unlock(&parent->p->mutex); |
1da177e4 LT |
471 | |
472 | class_put(parent); | |
473 | } | |
474 | ||
319684b1 BP |
475 | ssize_t show_class_attr_string(struct class *class, |
476 | struct class_attribute *attr, char *buf) | |
869dfc87 AK |
477 | { |
478 | struct class_attribute_string *cs; | |
d34898de | 479 | |
869dfc87 | 480 | cs = container_of(attr, struct class_attribute_string, attr); |
948b3edb | 481 | return sysfs_emit(buf, "%s\n", cs->str); |
869dfc87 AK |
482 | } |
483 | ||
484 | EXPORT_SYMBOL_GPL(show_class_attr_string); | |
485 | ||
46227094 JD |
486 | struct class_compat { |
487 | struct kobject *kobj; | |
488 | }; | |
489 | ||
490 | /** | |
491 | * class_compat_register - register a compatibility class | |
492 | * @name: the name of the class | |
493 | * | |
494 | * Compatibility class are meant as a temporary user-space compatibility | |
495 | * workaround when converting a family of class devices to a bus devices. | |
496 | */ | |
497 | struct class_compat *class_compat_register(const char *name) | |
498 | { | |
499 | struct class_compat *cls; | |
500 | ||
501 | cls = kmalloc(sizeof(struct class_compat), GFP_KERNEL); | |
502 | if (!cls) | |
503 | return NULL; | |
504 | cls->kobj = kobject_create_and_add(name, &class_kset->kobj); | |
505 | if (!cls->kobj) { | |
506 | kfree(cls); | |
507 | return NULL; | |
508 | } | |
509 | return cls; | |
510 | } | |
511 | EXPORT_SYMBOL_GPL(class_compat_register); | |
512 | ||
513 | /** | |
514 | * class_compat_unregister - unregister a compatibility class | |
515 | * @cls: the class to unregister | |
516 | */ | |
517 | void class_compat_unregister(struct class_compat *cls) | |
518 | { | |
519 | kobject_put(cls->kobj); | |
520 | kfree(cls); | |
521 | } | |
522 | EXPORT_SYMBOL_GPL(class_compat_unregister); | |
523 | ||
524 | /** | |
525 | * class_compat_create_link - create a compatibility class device link to | |
526 | * a bus device | |
527 | * @cls: the compatibility class | |
528 | * @dev: the target bus device | |
529 | * @device_link: an optional device to which a "device" link should be created | |
530 | */ | |
531 | int class_compat_create_link(struct class_compat *cls, struct device *dev, | |
532 | struct device *device_link) | |
533 | { | |
534 | int error; | |
535 | ||
536 | error = sysfs_create_link(cls->kobj, &dev->kobj, dev_name(dev)); | |
537 | if (error) | |
538 | return error; | |
539 | ||
540 | /* | |
541 | * Optionally add a "device" link (typically to the parent), as a | |
542 | * class device would have one and we want to provide as much | |
543 | * backwards compatibility as possible. | |
544 | */ | |
545 | if (device_link) { | |
546 | error = sysfs_create_link(&dev->kobj, &device_link->kobj, | |
547 | "device"); | |
548 | if (error) | |
549 | sysfs_remove_link(cls->kobj, dev_name(dev)); | |
550 | } | |
551 | ||
552 | return error; | |
553 | } | |
554 | EXPORT_SYMBOL_GPL(class_compat_create_link); | |
555 | ||
556 | /** | |
557 | * class_compat_remove_link - remove a compatibility class device link to | |
558 | * a bus device | |
559 | * @cls: the compatibility class | |
560 | * @dev: the target bus device | |
561 | * @device_link: an optional device to which a "device" link was previously | |
562 | * created | |
563 | */ | |
564 | void class_compat_remove_link(struct class_compat *cls, struct device *dev, | |
565 | struct device *device_link) | |
566 | { | |
567 | if (device_link) | |
568 | sysfs_remove_link(&dev->kobj, "device"); | |
569 | sysfs_remove_link(cls->kobj, dev_name(dev)); | |
570 | } | |
571 | EXPORT_SYMBOL_GPL(class_compat_remove_link); | |
572 | ||
1da177e4 LT |
573 | int __init classes_init(void) |
574 | { | |
443dbf90 GKH |
575 | class_kset = kset_create_and_add("class", NULL, NULL); |
576 | if (!class_kset) | |
577 | return -ENOMEM; | |
1da177e4 LT |
578 | return 0; |
579 | } | |
580 | ||
58292cbe TH |
581 | EXPORT_SYMBOL_GPL(class_create_file_ns); |
582 | EXPORT_SYMBOL_GPL(class_remove_file_ns); | |
1da177e4 | 583 | EXPORT_SYMBOL_GPL(class_unregister); |
e9ba6365 | 584 | EXPORT_SYMBOL_GPL(class_destroy); |
1da177e4 | 585 | |
1da177e4 LT |
586 | EXPORT_SYMBOL_GPL(class_interface_register); |
587 | EXPORT_SYMBOL_GPL(class_interface_unregister); |