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/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>
22 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
23 #define to_class(obj) container_of(obj, struct class, subsys.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 class_ktype = {
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, NULL);
77 int class_create_file(struct class * cls, const struct class_attribute * attr)
81 error = sysfs_create_file(&cls->subsys.kobj, &attr->attr);
87 void class_remove_file(struct class * cls, const struct class_attribute * attr)
90 sysfs_remove_file(&cls->subsys.kobj, &attr->attr);
93 static struct class *class_get(struct class *cls)
96 return container_of(kset_get(&cls->subsys), struct class, subsys);
100 static void class_put(struct class * cls)
103 kset_put(&cls->subsys);
107 static int add_class_attrs(struct class * cls)
112 if (cls->class_attrs) {
113 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
114 error = class_create_file(cls,&cls->class_attrs[i]);
123 class_remove_file(cls,&cls->class_attrs[i]);
127 static void remove_class_attrs(struct class * cls)
131 if (cls->class_attrs) {
132 for (i = 0; attr_name(cls->class_attrs[i]); i++)
133 class_remove_file(cls,&cls->class_attrs[i]);
137 int class_register(struct class * cls)
141 pr_debug("device class '%s': registering\n", cls->name);
143 INIT_LIST_HEAD(&cls->children);
144 INIT_LIST_HEAD(&cls->devices);
145 INIT_LIST_HEAD(&cls->interfaces);
146 kset_init(&cls->class_dirs);
147 init_MUTEX(&cls->sem);
148 error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);
152 cls->subsys.kobj.kset = &class_subsys;
153 cls->subsys.kobj.ktype = &class_ktype;
155 error = subsystem_register(&cls->subsys);
157 error = add_class_attrs(class_get(cls));
163 void class_unregister(struct class * cls)
165 pr_debug("device class '%s': unregistering\n", cls->name);
166 remove_class_attrs(cls);
167 subsystem_unregister(&cls->subsys);
170 static void class_create_release(struct class *cls)
172 pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
176 static void class_device_create_release(struct class_device *class_dev)
178 pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
182 /* needed to allow these devices to have parent class devices */
183 static int class_device_create_uevent(struct class_device *class_dev,
184 struct kobj_uevent_env *env)
186 pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
191 * class_create - create a struct class structure
192 * @owner: pointer to the module that is to "own" this struct class
193 * @name: pointer to a string for the name of this class.
195 * This is used to create a struct class pointer that can then be used
196 * in calls to class_device_create().
198 * Note, the pointer created here is to be destroyed when finished by
199 * making a call to class_destroy().
201 struct class *class_create(struct module *owner, const char *name)
206 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
214 cls->class_release = class_create_release;
215 cls->release = class_device_create_release;
217 retval = class_register(cls);
225 return ERR_PTR(retval);
229 * class_destroy - destroys a struct class structure
230 * @cls: pointer to the struct class that is to be destroyed
232 * Note, the pointer to be destroyed must have been created with a call
235 void class_destroy(struct class *cls)
237 if ((cls == NULL) || (IS_ERR(cls)))
240 class_unregister(cls);
243 /* Class Device Stuff */
245 int class_device_create_file(struct class_device * class_dev,
246 const struct class_device_attribute * attr)
250 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
254 void class_device_remove_file(struct class_device * class_dev,
255 const struct class_device_attribute * attr)
258 sysfs_remove_file(&class_dev->kobj, &attr->attr);
261 int class_device_create_bin_file(struct class_device *class_dev,
262 struct bin_attribute *attr)
266 error = sysfs_create_bin_file(&class_dev->kobj, attr);
270 void class_device_remove_bin_file(struct class_device *class_dev,
271 struct bin_attribute *attr)
274 sysfs_remove_bin_file(&class_dev->kobj, attr);
278 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
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->show)
286 ret = class_dev_attr->show(cd, buf);
291 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
292 const char * buf, size_t count)
294 struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
295 struct class_device * cd = to_class_dev(kobj);
298 if (class_dev_attr->store)
299 ret = class_dev_attr->store(cd, buf, count);
303 static struct sysfs_ops class_dev_sysfs_ops = {
304 .show = class_device_attr_show,
305 .store = class_device_attr_store,
308 static void class_dev_release(struct kobject * kobj)
310 struct class_device *cd = to_class_dev(kobj);
311 struct class * cls = cd->class;
313 pr_debug("device class '%s': release.\n", cd->class_id);
317 else if (cls->release)
320 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
321 "it is broken and must be fixed.\n",
327 static struct kobj_type class_device_ktype = {
328 .sysfs_ops = &class_dev_sysfs_ops,
329 .release = class_dev_release,
332 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
334 struct kobj_type *ktype = get_ktype(kobj);
336 if (ktype == &class_device_ktype) {
337 struct class_device *class_dev = to_class_dev(kobj);
338 if (class_dev->class)
344 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
346 struct class_device *class_dev = to_class_dev(kobj);
348 return class_dev->class->name;
351 #ifdef CONFIG_SYSFS_DEPRECATED
352 char *make_class_name(const char *name, struct kobject *kobj)
357 size = strlen(name) + strlen(kobject_name(kobj)) + 2;
359 class_name = kmalloc(size, GFP_KERNEL);
363 strcpy(class_name, name);
364 strcat(class_name, ":");
365 strcat(class_name, kobject_name(kobj));
369 static int make_deprecated_class_device_links(struct class_device *class_dev)
377 class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
379 error = sysfs_create_link(&class_dev->dev->kobj,
380 &class_dev->kobj, class_name);
387 static void remove_deprecated_class_device_links(struct class_device *class_dev)
394 class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
396 sysfs_remove_link(&class_dev->dev->kobj, class_name);
400 static inline int make_deprecated_class_device_links(struct class_device *cd)
402 static void remove_deprecated_class_device_links(struct class_device *cd)
406 static int class_uevent(struct kset *kset, struct kobject *kobj,
407 struct kobj_uevent_env *env)
409 struct class_device *class_dev = to_class_dev(kobj);
410 struct device *dev = class_dev->dev;
413 pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
415 if (MAJOR(class_dev->devt)) {
416 add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt));
418 add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt));
422 const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
424 add_uevent_var(env, "PHYSDEVPATH=%s", path);
429 add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
432 add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
435 if (class_dev->uevent) {
436 /* have the class device specific function add its stuff */
437 retval = class_dev->uevent(class_dev, env);
439 pr_debug("class_dev->uevent() returned %d\n", retval);
440 } else if (class_dev->class->uevent) {
441 /* have the class specific function add its stuff */
442 retval = class_dev->class->uevent(class_dev, env);
444 pr_debug("class->uevent() returned %d\n", retval);
450 static struct kset_uevent_ops class_uevent_ops = {
451 .filter = class_uevent_filter,
452 .name = class_uevent_name,
453 .uevent = class_uevent,
456 static decl_subsys(class_obj, &class_uevent_ops);
459 static int class_device_add_attrs(struct class_device * cd)
463 struct class * cls = cd->class;
465 if (cls->class_dev_attrs) {
466 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
467 error = class_device_create_file(cd,
468 &cls->class_dev_attrs[i]);
477 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
481 static void class_device_remove_attrs(struct class_device * cd)
484 struct class * cls = cd->class;
486 if (cls->class_dev_attrs) {
487 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
488 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
492 static int class_device_add_groups(struct class_device * cd)
498 for (i = 0; cd->groups[i]; i++) {
499 error = sysfs_create_group(&cd->kobj, cd->groups[i]);
502 sysfs_remove_group(&cd->kobj, cd->groups[i]);
511 static void class_device_remove_groups(struct class_device * cd)
515 for (i = 0; cd->groups[i]; i++) {
516 sysfs_remove_group(&cd->kobj, cd->groups[i]);
521 static ssize_t show_dev(struct class_device *class_dev, char *buf)
523 return print_dev_t(buf, class_dev->devt);
526 static struct class_device_attribute class_devt_attr =
527 __ATTR(dev, S_IRUGO, show_dev, NULL);
529 static ssize_t store_uevent(struct class_device *class_dev,
530 const char *buf, size_t count)
532 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
536 static struct class_device_attribute class_uevent_attr =
537 __ATTR(uevent, S_IWUSR, NULL, store_uevent);
539 void class_device_initialize(struct class_device *class_dev)
541 class_dev->kobj.kset = &class_obj_subsys;
542 class_dev->kobj.ktype = &class_device_ktype;
543 kobject_init(&class_dev->kobj);
544 INIT_LIST_HEAD(&class_dev->node);
547 int class_device_add(struct class_device *class_dev)
549 struct class *parent_class = NULL;
550 struct class_device *parent_class_dev = NULL;
551 struct class_interface *class_intf;
554 class_dev = class_device_get(class_dev);
558 if (!strlen(class_dev->class_id))
561 parent_class = class_get(class_dev->class);
565 parent_class_dev = class_device_get(class_dev->parent);
567 pr_debug("CLASS: registering class device: ID = '%s'\n",
568 class_dev->class_id);
570 /* first, register with generic layer. */
571 error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
575 if (parent_class_dev)
576 class_dev->kobj.parent = &parent_class_dev->kobj;
578 class_dev->kobj.parent = &parent_class->subsys.kobj;
580 error = kobject_add(&class_dev->kobj);
584 /* add the needed attributes to this device */
585 error = sysfs_create_link(&class_dev->kobj,
586 &parent_class->subsys.kobj, "subsystem");
590 error = class_device_create_file(class_dev, &class_uevent_attr);
594 if (MAJOR(class_dev->devt)) {
595 error = class_device_create_file(class_dev, &class_devt_attr);
600 error = class_device_add_attrs(class_dev);
604 if (class_dev->dev) {
605 error = sysfs_create_link(&class_dev->kobj,
606 &class_dev->dev->kobj, "device");
611 error = class_device_add_groups(class_dev);
615 error = make_deprecated_class_device_links(class_dev);
619 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
621 /* notify any interfaces this device is now here */
622 down(&parent_class->sem);
623 list_add_tail(&class_dev->node, &parent_class->children);
624 list_for_each_entry(class_intf, &parent_class->interfaces, node) {
626 class_intf->add(class_dev, class_intf);
628 up(&parent_class->sem);
633 class_device_remove_groups(class_dev);
636 sysfs_remove_link(&class_dev->kobj, "device");
638 class_device_remove_attrs(class_dev);
640 if (MAJOR(class_dev->devt))
641 class_device_remove_file(class_dev, &class_devt_attr);
643 class_device_remove_file(class_dev, &class_uevent_attr);
645 kobject_del(&class_dev->kobj);
648 class_device_put(parent_class_dev);
649 class_put(parent_class);
651 class_device_put(class_dev);
655 int class_device_register(struct class_device *class_dev)
657 class_device_initialize(class_dev);
658 return class_device_add(class_dev);
662 * class_device_create - creates a class device and registers it with sysfs
663 * @cls: pointer to the struct class that this device should be registered to.
664 * @parent: pointer to the parent struct class_device of this new device, if any.
665 * @devt: the dev_t for the char device to be added.
666 * @device: a pointer to a struct device that is assiociated with this class device.
667 * @fmt: string for the class device's name
669 * This function can be used by char device classes. A struct
670 * class_device will be created in sysfs, registered to the specified
672 * A "dev" file will be created, showing the dev_t for the device, if
673 * the dev_t is not 0,0.
674 * If a pointer to a parent struct class_device is passed in, the newly
675 * created struct class_device will be a child of that device in sysfs.
676 * The pointer to the struct class_device will be returned from the
677 * call. Any further sysfs files that might be required can be created
678 * using this pointer.
680 * Note: the struct class passed to this function must have previously
681 * been created with a call to class_create().
683 struct class_device *class_device_create(struct class *cls,
684 struct class_device *parent,
686 struct device *device,
687 const char *fmt, ...)
690 struct class_device *class_dev = NULL;
691 int retval = -ENODEV;
693 if (cls == NULL || IS_ERR(cls))
696 class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
702 class_dev->devt = devt;
703 class_dev->dev = device;
704 class_dev->class = cls;
705 class_dev->parent = parent;
706 class_dev->release = class_device_create_release;
707 class_dev->uevent = class_device_create_uevent;
710 vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
712 retval = class_device_register(class_dev);
720 return ERR_PTR(retval);
723 void class_device_del(struct class_device *class_dev)
725 struct class *parent_class = class_dev->class;
726 struct class_device *parent_device = class_dev->parent;
727 struct class_interface *class_intf;
730 down(&parent_class->sem);
731 list_del_init(&class_dev->node);
732 list_for_each_entry(class_intf, &parent_class->interfaces, node)
733 if (class_intf->remove)
734 class_intf->remove(class_dev, class_intf);
735 up(&parent_class->sem);
738 if (class_dev->dev) {
739 remove_deprecated_class_device_links(class_dev);
740 sysfs_remove_link(&class_dev->kobj, "device");
742 sysfs_remove_link(&class_dev->kobj, "subsystem");
743 class_device_remove_file(class_dev, &class_uevent_attr);
744 if (MAJOR(class_dev->devt))
745 class_device_remove_file(class_dev, &class_devt_attr);
746 class_device_remove_attrs(class_dev);
747 class_device_remove_groups(class_dev);
749 kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
750 kobject_del(&class_dev->kobj);
752 class_device_put(parent_device);
753 class_put(parent_class);
756 void class_device_unregister(struct class_device *class_dev)
758 pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
759 class_dev->class_id);
760 class_device_del(class_dev);
761 class_device_put(class_dev);
765 * class_device_destroy - removes a class device that was created with class_device_create()
766 * @cls: the pointer to the struct class that this device was registered * with.
767 * @devt: the dev_t of the device that was previously registered.
769 * This call unregisters and cleans up a class device that was created with a
770 * call to class_device_create()
772 void class_device_destroy(struct class *cls, dev_t devt)
774 struct class_device *class_dev = NULL;
775 struct class_device *class_dev_tmp;
778 list_for_each_entry(class_dev_tmp, &cls->children, node) {
779 if (class_dev_tmp->devt == devt) {
780 class_dev = class_dev_tmp;
787 class_device_unregister(class_dev);
790 struct class_device * class_device_get(struct class_device *class_dev)
793 return to_class_dev(kobject_get(&class_dev->kobj));
797 void class_device_put(struct class_device *class_dev)
800 kobject_put(&class_dev->kobj);
804 int class_interface_register(struct class_interface *class_intf)
806 struct class *parent;
807 struct class_device *class_dev;
810 if (!class_intf || !class_intf->class)
813 parent = class_get(class_intf->class);
818 list_add_tail(&class_intf->node, &parent->interfaces);
819 if (class_intf->add) {
820 list_for_each_entry(class_dev, &parent->children, node)
821 class_intf->add(class_dev, class_intf);
823 if (class_intf->add_dev) {
824 list_for_each_entry(dev, &parent->devices, node)
825 class_intf->add_dev(dev, class_intf);
832 void class_interface_unregister(struct class_interface *class_intf)
834 struct class * parent = class_intf->class;
835 struct class_device *class_dev;
842 list_del_init(&class_intf->node);
843 if (class_intf->remove) {
844 list_for_each_entry(class_dev, &parent->children, node)
845 class_intf->remove(class_dev, class_intf);
847 if (class_intf->remove_dev) {
848 list_for_each_entry(dev, &parent->devices, node)
849 class_intf->remove_dev(dev, class_intf);
856 int __init classes_init(void)
860 retval = subsystem_register(&class_subsys);
864 /* ick, this is ugly, the things we go through to keep from showing up
866 kset_init(&class_obj_subsys);
867 if (!class_obj_subsys.kobj.parent)
868 class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
872 EXPORT_SYMBOL_GPL(class_create_file);
873 EXPORT_SYMBOL_GPL(class_remove_file);
874 EXPORT_SYMBOL_GPL(class_register);
875 EXPORT_SYMBOL_GPL(class_unregister);
876 EXPORT_SYMBOL_GPL(class_create);
877 EXPORT_SYMBOL_GPL(class_destroy);
879 EXPORT_SYMBOL_GPL(class_device_register);
880 EXPORT_SYMBOL_GPL(class_device_unregister);
881 EXPORT_SYMBOL_GPL(class_device_initialize);
882 EXPORT_SYMBOL_GPL(class_device_add);
883 EXPORT_SYMBOL_GPL(class_device_del);
884 EXPORT_SYMBOL_GPL(class_device_get);
885 EXPORT_SYMBOL_GPL(class_device_put);
886 EXPORT_SYMBOL_GPL(class_device_create);
887 EXPORT_SYMBOL_GPL(class_device_destroy);
888 EXPORT_SYMBOL_GPL(class_device_create_file);
889 EXPORT_SYMBOL_GPL(class_device_remove_file);
890 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
891 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
893 EXPORT_SYMBOL_GPL(class_interface_register);
894 EXPORT_SYMBOL_GPL(class_interface_unregister);