2 * class.c - basic device class management
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.
9 * This file is released under the GPLv2
13 #include <linux/config.h>
14 #include <linux/device.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/string.h>
18 #include <linux/kdev_t.h>
19 #include <linux/err.h>
22 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
23 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
26 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
28 struct class_attribute * class_attr = to_class_attr(attr);
29 struct class * dc = to_class(kobj);
33 ret = class_attr->show(dc, buf);
38 class_attr_store(struct kobject * kobj, struct attribute * attr,
39 const char * buf, size_t count)
41 struct class_attribute * class_attr = to_class_attr(attr);
42 struct class * dc = to_class(kobj);
45 if (class_attr->store)
46 ret = class_attr->store(dc, buf, count);
50 static void class_release(struct kobject * kobj)
52 struct class *class = to_class(kobj);
54 pr_debug("class '%s': release.\n", class->name);
56 if (class->class_release)
57 class->class_release(class);
59 pr_debug("class '%s' does not have a release() function, "
60 "be careful\n", class->name);
63 static struct sysfs_ops class_sysfs_ops = {
64 .show = class_attr_show,
65 .store = class_attr_store,
68 static struct kobj_type ktype_class = {
69 .sysfs_ops = &class_sysfs_ops,
70 .release = class_release,
73 /* Hotplug events for classes go to the class_obj subsys */
74 static decl_subsys(class, &ktype_class, NULL);
77 int class_create_file(struct class * cls, const struct class_attribute * attr)
81 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
87 void class_remove_file(struct class * cls, const struct class_attribute * attr)
90 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
93 struct class * class_get(struct class * cls)
96 return container_of(subsys_get(&cls->subsys), struct class, subsys);
100 void class_put(struct class * cls)
102 subsys_put(&cls->subsys);
106 static int add_class_attrs(struct class * cls)
111 if (cls->class_attrs) {
112 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
113 error = class_create_file(cls,&cls->class_attrs[i]);
122 class_remove_file(cls,&cls->class_attrs[i]);
126 static void remove_class_attrs(struct class * cls)
130 if (cls->class_attrs) {
131 for (i = 0; attr_name(cls->class_attrs[i]); i++)
132 class_remove_file(cls,&cls->class_attrs[i]);
136 int class_register(struct class * cls)
140 pr_debug("device class '%s': registering\n", cls->name);
142 INIT_LIST_HEAD(&cls->children);
143 INIT_LIST_HEAD(&cls->interfaces);
144 init_MUTEX(&cls->sem);
145 error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
149 subsys_set_kset(cls, class_subsys);
151 error = subsystem_register(&cls->subsys);
153 error = add_class_attrs(class_get(cls));
159 void class_unregister(struct class * cls)
161 pr_debug("device class '%s': unregistering\n", cls->name);
162 remove_class_attrs(cls);
163 subsystem_unregister(&cls->subsys);
166 static void class_create_release(struct class *cls)
171 static void class_device_create_release(struct class_device *class_dev)
177 * class_create - create a struct class structure
178 * @owner: pointer to the module that is to "own" this struct class
179 * @name: pointer to a string for the name of this class.
181 * This is used to create a struct class pointer that can then be used
182 * in calls to class_device_create().
184 * Note, the pointer created here is to be destroyed when finished by
185 * making a call to class_destroy().
187 struct class *class_create(struct module *owner, char *name)
192 cls = kmalloc(sizeof(struct class), GFP_KERNEL);
197 memset(cls, 0x00, sizeof(struct class));
201 cls->class_release = class_create_release;
202 cls->release = class_device_create_release;
204 retval = class_register(cls);
212 return ERR_PTR(retval);
216 * class_destroy - destroys a struct class structure
217 * @cs: pointer to the struct class that is to be destroyed
219 * Note, the pointer to be destroyed must have been created with a call
222 void class_destroy(struct class *cls)
224 if ((cls == NULL) || (IS_ERR(cls)))
227 class_unregister(cls);
230 /* Class Device Stuff */
232 int class_device_create_file(struct class_device * class_dev,
233 const struct class_device_attribute * attr)
237 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
241 void class_device_remove_file(struct class_device * class_dev,
242 const struct class_device_attribute * attr)
245 sysfs_remove_file(&class_dev->kobj, &attr->attr);
248 int class_device_create_bin_file(struct class_device *class_dev,
249 struct bin_attribute *attr)
253 error = sysfs_create_bin_file(&class_dev->kobj, attr);
257 void class_device_remove_bin_file(struct class_device *class_dev,
258 struct bin_attribute *attr)
261 sysfs_remove_bin_file(&class_dev->kobj, attr);
265 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
268 struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
269 struct class_device * cd = to_class_dev(kobj);
272 if (class_dev_attr->show)
273 ret = class_dev_attr->show(cd, buf);
278 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
279 const char * buf, size_t count)
281 struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
282 struct class_device * cd = to_class_dev(kobj);
285 if (class_dev_attr->store)
286 ret = class_dev_attr->store(cd, buf, count);
290 static struct sysfs_ops class_dev_sysfs_ops = {
291 .show = class_device_attr_show,
292 .store = class_device_attr_store,
295 static void class_dev_release(struct kobject * kobj)
297 struct class_device *cd = to_class_dev(kobj);
298 struct class * cls = cd->class;
300 pr_debug("device class '%s': release.\n", cd->class_id);
305 printk(KERN_ERR "Device class '%s' does not have a release() function, "
306 "it is broken and must be fixed.\n",
312 static struct kobj_type ktype_class_device = {
313 .sysfs_ops = &class_dev_sysfs_ops,
314 .release = class_dev_release,
317 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
319 struct kobj_type *ktype = get_ktype(kobj);
321 if (ktype == &ktype_class_device) {
322 struct class_device *class_dev = to_class_dev(kobj);
323 if (class_dev->class)
329 static const char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
331 struct class_device *class_dev = to_class_dev(kobj);
333 return class_dev->class->name;
336 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
337 int num_envp, char *buffer, int buffer_size)
339 struct class_device *class_dev = to_class_dev(kobj);
344 pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
346 if (class_dev->dev) {
347 /* add physical device, backing this device */
348 struct device *dev = class_dev->dev;
349 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
351 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
352 &length, "PHYSDEVPATH=%s", path);
356 add_hotplug_env_var(envp, num_envp, &i,
357 buffer, buffer_size, &length,
358 "PHYSDEVBUS=%s", dev->bus->name);
361 add_hotplug_env_var(envp, num_envp, &i,
362 buffer, buffer_size, &length,
363 "PHYSDEVDRIVER=%s", dev->driver->name);
366 if (MAJOR(class_dev->devt)) {
367 add_hotplug_env_var(envp, num_envp, &i,
368 buffer, buffer_size, &length,
369 "MAJOR=%u", MAJOR(class_dev->devt));
371 add_hotplug_env_var(envp, num_envp, &i,
372 buffer, buffer_size, &length,
373 "MINOR=%u", MINOR(class_dev->devt));
376 /* terminate, set to next free slot, shrink available space */
380 buffer = &buffer[length];
381 buffer_size -= length;
383 if (class_dev->class->hotplug) {
384 /* have the bus specific function add its stuff */
385 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
386 buffer, buffer_size);
388 pr_debug ("%s - hotplug() returned %d\n",
389 __FUNCTION__, retval);
396 static struct kset_hotplug_ops class_hotplug_ops = {
397 .filter = class_hotplug_filter,
398 .name = class_hotplug_name,
399 .hotplug = class_hotplug,
402 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
405 static int class_device_add_attrs(struct class_device * cd)
409 struct class * cls = cd->class;
411 if (cls->class_dev_attrs) {
412 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
413 error = class_device_create_file(cd,
414 &cls->class_dev_attrs[i]);
423 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
427 static void class_device_remove_attrs(struct class_device * cd)
430 struct class * cls = cd->class;
432 if (cls->class_dev_attrs) {
433 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
434 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
438 static ssize_t show_dev(struct class_device *class_dev, char *buf)
440 return print_dev_t(buf, class_dev->devt);
443 void class_device_initialize(struct class_device *class_dev)
445 kobj_set_kset_s(class_dev, class_obj_subsys);
446 kobject_init(&class_dev->kobj);
447 INIT_LIST_HEAD(&class_dev->node);
450 int class_device_add(struct class_device *class_dev)
452 struct class * parent = NULL;
453 struct class_interface * class_intf;
456 class_dev = class_device_get(class_dev);
460 if (!strlen(class_dev->class_id)) {
465 parent = class_get(class_dev->class);
467 pr_debug("CLASS: registering class device: ID = '%s'\n",
468 class_dev->class_id);
470 /* first, register with generic layer. */
471 kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
473 class_dev->kobj.parent = &parent->subsys.kset.kobj;
475 if ((error = kobject_add(&class_dev->kobj)))
478 /* add the needed attributes to this device */
479 if (MAJOR(class_dev->devt)) {
480 struct class_device_attribute *attr;
481 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
484 kobject_del(&class_dev->kobj);
487 memset(attr, sizeof(*attr), 0x00);
488 attr->attr.name = "dev";
489 attr->attr.mode = S_IRUGO;
490 attr->attr.owner = parent->owner;
491 attr->show = show_dev;
493 class_device_create_file(class_dev, attr);
494 class_dev->devt_attr = attr;
497 class_device_add_attrs(class_dev);
499 sysfs_create_link(&class_dev->kobj,
500 &class_dev->dev->kobj, "device");
502 /* notify any interfaces this device is now here */
505 list_add_tail(&class_dev->node, &parent->children);
506 list_for_each_entry(class_intf, &parent->interfaces, node)
508 class_intf->add(class_dev);
511 kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
516 class_device_put(class_dev);
520 int class_device_register(struct class_device *class_dev)
522 class_device_initialize(class_dev);
523 return class_device_add(class_dev);
527 * class_device_create - creates a class device and registers it with sysfs
528 * @cs: pointer to the struct class that this device should be registered to.
529 * @dev: the dev_t for the char device to be added.
530 * @device: a pointer to a struct device that is assiociated with this class device.
531 * @fmt: string for the class device's name
533 * This function can be used by char device classes. A struct
534 * class_device will be created in sysfs, registered to the specified
535 * class. A "dev" file will be created, showing the dev_t for the
536 * device. The pointer to the struct class_device will be returned from
537 * the call. Any further sysfs files that might be required can be
538 * created using this pointer.
540 * Note: the struct class passed to this function must have previously
541 * been created with a call to class_create().
543 struct class_device *class_device_create(struct class *cls, dev_t devt,
544 struct device *device, char *fmt, ...)
547 struct class_device *class_dev = NULL;
548 int retval = -ENODEV;
550 if (cls == NULL || IS_ERR(cls))
553 class_dev = kmalloc(sizeof(struct class_device), GFP_KERNEL);
558 memset(class_dev, 0x00, sizeof(struct class_device));
560 class_dev->devt = devt;
561 class_dev->dev = device;
562 class_dev->class = cls;
565 vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
567 retval = class_device_register(class_dev);
575 return ERR_PTR(retval);
578 void class_device_del(struct class_device *class_dev)
580 struct class * parent = class_dev->class;
581 struct class_interface * class_intf;
585 list_del_init(&class_dev->node);
586 list_for_each_entry(class_intf, &parent->interfaces, node)
587 if (class_intf->remove)
588 class_intf->remove(class_dev);
593 sysfs_remove_link(&class_dev->kobj, "device");
594 if (class_dev->devt_attr) {
595 class_device_remove_file(class_dev, class_dev->devt_attr);
596 kfree(class_dev->devt_attr);
597 class_dev->devt_attr = NULL;
599 class_device_remove_attrs(class_dev);
601 kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
602 kobject_del(&class_dev->kobj);
608 void class_device_unregister(struct class_device *class_dev)
610 pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
611 class_dev->class_id);
612 class_device_del(class_dev);
613 class_device_put(class_dev);
617 * class_device_destroy - removes a class device that was created with class_device_create()
618 * @cls: the pointer to the struct class that this device was registered * with.
619 * @dev: the dev_t of the device that was previously registered.
621 * This call unregisters and cleans up a class device that was created with a
622 * call to class_device_create()
624 void class_device_destroy(struct class *cls, dev_t devt)
626 struct class_device *class_dev = NULL;
627 struct class_device *class_dev_tmp;
630 list_for_each_entry(class_dev_tmp, &cls->children, node) {
631 if (class_dev_tmp->devt == devt) {
632 class_dev = class_dev_tmp;
639 class_device_unregister(class_dev);
642 int class_device_rename(struct class_device *class_dev, char *new_name)
646 class_dev = class_device_get(class_dev);
650 pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
653 strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
655 error = kobject_rename(&class_dev->kobj, new_name);
657 class_device_put(class_dev);
662 struct class_device * class_device_get(struct class_device *class_dev)
665 return to_class_dev(kobject_get(&class_dev->kobj));
669 void class_device_put(struct class_device *class_dev)
671 kobject_put(&class_dev->kobj);
675 int class_interface_register(struct class_interface *class_intf)
677 struct class *parent;
678 struct class_device *class_dev;
680 if (!class_intf || !class_intf->class)
683 parent = class_get(class_intf->class);
688 list_add_tail(&class_intf->node, &parent->interfaces);
689 if (class_intf->add) {
690 list_for_each_entry(class_dev, &parent->children, node)
691 class_intf->add(class_dev);
698 void class_interface_unregister(struct class_interface *class_intf)
700 struct class * parent = class_intf->class;
701 struct class_device *class_dev;
707 list_del_init(&class_intf->node);
708 if (class_intf->remove) {
709 list_for_each_entry(class_dev, &parent->children, node)
710 class_intf->remove(class_dev);
719 int __init classes_init(void)
723 retval = subsystem_register(&class_subsys);
727 /* ick, this is ugly, the things we go through to keep from showing up
729 subsystem_init(&class_obj_subsys);
730 if (!class_obj_subsys.kset.subsys)
731 class_obj_subsys.kset.subsys = &class_obj_subsys;
735 EXPORT_SYMBOL_GPL(class_create_file);
736 EXPORT_SYMBOL_GPL(class_remove_file);
737 EXPORT_SYMBOL_GPL(class_register);
738 EXPORT_SYMBOL_GPL(class_unregister);
739 EXPORT_SYMBOL_GPL(class_get);
740 EXPORT_SYMBOL_GPL(class_put);
741 EXPORT_SYMBOL_GPL(class_create);
742 EXPORT_SYMBOL_GPL(class_destroy);
744 EXPORT_SYMBOL_GPL(class_device_register);
745 EXPORT_SYMBOL_GPL(class_device_unregister);
746 EXPORT_SYMBOL_GPL(class_device_initialize);
747 EXPORT_SYMBOL_GPL(class_device_add);
748 EXPORT_SYMBOL_GPL(class_device_del);
749 EXPORT_SYMBOL_GPL(class_device_get);
750 EXPORT_SYMBOL_GPL(class_device_put);
751 EXPORT_SYMBOL_GPL(class_device_create);
752 EXPORT_SYMBOL_GPL(class_device_destroy);
753 EXPORT_SYMBOL_GPL(class_device_create_file);
754 EXPORT_SYMBOL_GPL(class_device_remove_file);
755 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
756 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
758 EXPORT_SYMBOL_GPL(class_interface_register);
759 EXPORT_SYMBOL_GPL(class_interface_unregister);