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>
20 #include <linux/slab.h>
23 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
24 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
27 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
29 struct class_attribute * class_attr = to_class_attr(attr);
30 struct class * dc = to_class(kobj);
34 ret = class_attr->show(dc, buf);
39 class_attr_store(struct kobject * kobj, struct attribute * attr,
40 const char * buf, size_t count)
42 struct class_attribute * class_attr = to_class_attr(attr);
43 struct class * dc = to_class(kobj);
46 if (class_attr->store)
47 ret = class_attr->store(dc, buf, count);
51 static void class_release(struct kobject * kobj)
53 struct class *class = to_class(kobj);
55 pr_debug("class '%s': release.\n", class->name);
57 if (class->class_release)
58 class->class_release(class);
60 pr_debug("class '%s' does not have a release() function, "
61 "be careful\n", class->name);
64 static struct sysfs_ops class_sysfs_ops = {
65 .show = class_attr_show,
66 .store = class_attr_store,
69 static struct kobj_type ktype_class = {
70 .sysfs_ops = &class_sysfs_ops,
71 .release = class_release,
74 /* Hotplug events for classes go to the class_obj subsys */
75 static decl_subsys(class, &ktype_class, NULL);
78 int class_create_file(struct class * cls, const struct class_attribute * attr)
82 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
88 void class_remove_file(struct class * cls, const struct class_attribute * attr)
91 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
94 static struct class *class_get(struct class *cls)
97 return container_of(subsys_get(&cls->subsys), struct class, subsys);
101 static void class_put(struct class * cls)
104 subsys_put(&cls->subsys);
108 static int add_class_attrs(struct class * cls)
113 if (cls->class_attrs) {
114 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
115 error = class_create_file(cls,&cls->class_attrs[i]);
124 class_remove_file(cls,&cls->class_attrs[i]);
128 static void remove_class_attrs(struct class * cls)
132 if (cls->class_attrs) {
133 for (i = 0; attr_name(cls->class_attrs[i]); i++)
134 class_remove_file(cls,&cls->class_attrs[i]);
138 int class_register(struct class * cls)
142 pr_debug("device class '%s': registering\n", cls->name);
144 INIT_LIST_HEAD(&cls->children);
145 INIT_LIST_HEAD(&cls->interfaces);
146 init_MUTEX(&cls->sem);
147 error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
151 subsys_set_kset(cls, class_subsys);
153 error = subsystem_register(&cls->subsys);
155 error = add_class_attrs(class_get(cls));
161 void class_unregister(struct class * cls)
163 pr_debug("device class '%s': unregistering\n", cls->name);
164 remove_class_attrs(cls);
165 subsystem_unregister(&cls->subsys);
168 static void class_create_release(struct class *cls)
170 pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
174 static void class_device_create_release(struct class_device *class_dev)
176 pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
180 /* needed to allow these devices to have parent class devices */
181 static int class_device_create_uevent(struct class_device *class_dev,
182 char **envp, int num_envp,
183 char *buffer, int buffer_size)
185 pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
190 * class_create - create a struct class structure
191 * @owner: pointer to the module that is to "own" this struct class
192 * @name: pointer to a string for the name of this class.
194 * This is used to create a struct class pointer that can then be used
195 * in calls to class_device_create().
197 * Note, the pointer created here is to be destroyed when finished by
198 * making a call to class_destroy().
200 struct class *class_create(struct module *owner, char *name)
205 cls = kzalloc(sizeof(*cls), GFP_KERNEL);
213 cls->class_release = class_create_release;
214 cls->release = class_device_create_release;
216 retval = class_register(cls);
224 return ERR_PTR(retval);
228 * class_destroy - destroys a struct class structure
229 * @cs: pointer to the struct class that is to be destroyed
231 * Note, the pointer to be destroyed must have been created with a call
234 void class_destroy(struct class *cls)
236 if ((cls == NULL) || (IS_ERR(cls)))
239 class_unregister(cls);
242 /* Class Device Stuff */
244 int class_device_create_file(struct class_device * class_dev,
245 const struct class_device_attribute * attr)
249 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
253 void class_device_remove_file(struct class_device * class_dev,
254 const struct class_device_attribute * attr)
257 sysfs_remove_file(&class_dev->kobj, &attr->attr);
260 int class_device_create_bin_file(struct class_device *class_dev,
261 struct bin_attribute *attr)
265 error = sysfs_create_bin_file(&class_dev->kobj, attr);
269 void class_device_remove_bin_file(struct class_device *class_dev,
270 struct bin_attribute *attr)
273 sysfs_remove_bin_file(&class_dev->kobj, attr);
277 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
280 struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
281 struct class_device * cd = to_class_dev(kobj);
284 if (class_dev_attr->show)
285 ret = class_dev_attr->show(cd, buf);
290 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
291 const char * buf, size_t count)
293 struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
294 struct class_device * cd = to_class_dev(kobj);
297 if (class_dev_attr->store)
298 ret = class_dev_attr->store(cd, buf, count);
302 static struct sysfs_ops class_dev_sysfs_ops = {
303 .show = class_device_attr_show,
304 .store = class_device_attr_store,
307 static void class_dev_release(struct kobject * kobj)
309 struct class_device *cd = to_class_dev(kobj);
310 struct class * cls = cd->class;
312 pr_debug("device class '%s': release.\n", cd->class_id);
314 kfree(cd->devt_attr);
315 cd->devt_attr = NULL;
319 else if (cls->release)
322 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
323 "it is broken and must be fixed.\n",
329 static struct kobj_type ktype_class_device = {
330 .sysfs_ops = &class_dev_sysfs_ops,
331 .release = class_dev_release,
334 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
336 struct kobj_type *ktype = get_ktype(kobj);
338 if (ktype == &ktype_class_device) {
339 struct class_device *class_dev = to_class_dev(kobj);
340 if (class_dev->class)
346 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
348 struct class_device *class_dev = to_class_dev(kobj);
350 return class_dev->class->name;
353 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
354 int num_envp, char *buffer, int buffer_size)
356 struct class_device *class_dev = to_class_dev(kobj);
361 pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
363 if (class_dev->dev) {
364 /* add physical device, backing this device */
365 struct device *dev = class_dev->dev;
366 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
368 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
369 &length, "PHYSDEVPATH=%s", path);
373 add_uevent_var(envp, num_envp, &i,
374 buffer, buffer_size, &length,
375 "PHYSDEVBUS=%s", dev->bus->name);
378 add_uevent_var(envp, num_envp, &i,
379 buffer, buffer_size, &length,
380 "PHYSDEVDRIVER=%s", dev->driver->name);
383 if (MAJOR(class_dev->devt)) {
384 add_uevent_var(envp, num_envp, &i,
385 buffer, buffer_size, &length,
386 "MAJOR=%u", MAJOR(class_dev->devt));
388 add_uevent_var(envp, num_envp, &i,
389 buffer, buffer_size, &length,
390 "MINOR=%u", MINOR(class_dev->devt));
393 /* terminate, set to next free slot, shrink available space */
397 buffer = &buffer[length];
398 buffer_size -= length;
400 if (class_dev->uevent) {
401 /* have the class device specific function add its stuff */
402 retval = class_dev->uevent(class_dev, envp, num_envp,
403 buffer, buffer_size);
405 pr_debug("class_dev->uevent() returned %d\n", retval);
406 } else if (class_dev->class->uevent) {
407 /* have the class specific function add its stuff */
408 retval = class_dev->class->uevent(class_dev, envp, num_envp,
409 buffer, buffer_size);
411 pr_debug("class->uevent() returned %d\n", retval);
417 static struct kset_uevent_ops class_uevent_ops = {
418 .filter = class_uevent_filter,
419 .name = class_uevent_name,
420 .uevent = class_uevent,
423 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
426 static int class_device_add_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 error = class_device_create_file(cd,
435 &cls->class_dev_attrs[i]);
444 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
448 static void class_device_remove_attrs(struct class_device * cd)
451 struct class * cls = cd->class;
453 if (cls->class_dev_attrs) {
454 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
455 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
459 static int class_device_add_groups(struct class_device * cd)
465 for (i = 0; cd->groups[i]; i++) {
466 error = sysfs_create_group(&cd->kobj, cd->groups[i]);
469 sysfs_remove_group(&cd->kobj, cd->groups[i]);
478 static void class_device_remove_groups(struct class_device * cd)
482 for (i = 0; cd->groups[i]; i++) {
483 sysfs_remove_group(&cd->kobj, cd->groups[i]);
488 static ssize_t show_dev(struct class_device *class_dev, char *buf)
490 return print_dev_t(buf, class_dev->devt);
493 static ssize_t store_uevent(struct class_device *class_dev,
494 const char *buf, size_t count)
496 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
500 void class_device_initialize(struct class_device *class_dev)
502 kobj_set_kset_s(class_dev, class_obj_subsys);
503 kobject_init(&class_dev->kobj);
504 INIT_LIST_HEAD(&class_dev->node);
507 char *make_class_name(const char *name, struct kobject *kobj)
512 size = strlen(name) + strlen(kobject_name(kobj)) + 2;
514 class_name = kmalloc(size, GFP_KERNEL);
516 return ERR_PTR(-ENOMEM);
518 strcpy(class_name, name);
519 strcat(class_name, ":");
520 strcat(class_name, kobject_name(kobj));
524 int class_device_add(struct class_device *class_dev)
526 struct class *parent_class = NULL;
527 struct class_device *parent_class_dev = NULL;
528 struct class_interface *class_intf;
529 char *class_name = NULL;
532 class_dev = class_device_get(class_dev);
536 if (!strlen(class_dev->class_id))
539 parent_class = class_get(class_dev->class);
543 parent_class_dev = class_device_get(class_dev->parent);
545 pr_debug("CLASS: registering class device: ID = '%s'\n",
546 class_dev->class_id);
548 /* first, register with generic layer. */
549 error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
553 if (parent_class_dev)
554 class_dev->kobj.parent = &parent_class_dev->kobj;
556 class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
558 error = kobject_add(&class_dev->kobj);
562 /* add the needed attributes to this device */
563 class_dev->uevent_attr.attr.name = "uevent";
564 class_dev->uevent_attr.attr.mode = S_IWUSR;
565 class_dev->uevent_attr.attr.owner = parent_class->owner;
566 class_dev->uevent_attr.store = store_uevent;
567 error = class_device_create_file(class_dev, &class_dev->uevent_attr);
571 if (MAJOR(class_dev->devt)) {
572 struct class_device_attribute *attr;
573 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
578 attr->attr.name = "dev";
579 attr->attr.mode = S_IRUGO;
580 attr->attr.owner = parent_class->owner;
581 attr->show = show_dev;
582 error = class_device_create_file(class_dev, attr);
588 class_dev->devt_attr = attr;
591 error = class_device_add_attrs(class_dev);
595 if (class_dev->dev) {
596 class_name = make_class_name(class_dev->class->name,
598 error = sysfs_create_link(&class_dev->kobj,
599 &class_dev->dev->kobj, "device");
602 error = sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
608 error = class_device_add_groups(class_dev);
612 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
614 /* notify any interfaces this device is now here */
615 down(&parent_class->sem);
616 list_add_tail(&class_dev->node, &parent_class->children);
617 list_for_each_entry(class_intf, &parent_class->interfaces, node) {
619 class_intf->add(class_dev, class_intf);
621 up(&parent_class->sem);
627 sysfs_remove_link(&class_dev->kobj, class_name);
630 sysfs_remove_link(&class_dev->kobj, "device");
632 class_device_remove_attrs(class_dev);
634 if (class_dev->devt_attr)
635 class_device_remove_file(class_dev, class_dev->devt_attr);
637 class_device_remove_file(class_dev, &class_dev->uevent_attr);
639 kobject_del(&class_dev->kobj);
642 class_device_put(parent_class_dev);
643 class_put(parent_class);
645 class_device_put(class_dev);
650 int class_device_register(struct class_device *class_dev)
652 class_device_initialize(class_dev);
653 return class_device_add(class_dev);
657 * class_device_create - creates a class device and registers it with sysfs
658 * @cs: pointer to the struct class that this device should be registered to.
659 * @parent: pointer to the parent struct class_device of this new device, if any.
660 * @dev: the dev_t for the char device to be added.
661 * @device: a pointer to a struct device that is assiociated with this class device.
662 * @fmt: string for the class device's name
664 * This function can be used by char device classes. A struct
665 * class_device will be created in sysfs, registered to the specified
667 * A "dev" file will be created, showing the dev_t for the device, if
668 * the dev_t is not 0,0.
669 * If a pointer to a parent struct class_device is passed in, the newly
670 * created struct class_device will be a child of that device in sysfs.
671 * The pointer to the struct class_device will be returned from the
672 * call. Any further sysfs files that might be required can be created
673 * using this pointer.
675 * Note: the struct class passed to this function must have previously
676 * been created with a call to class_create().
678 struct class_device *class_device_create(struct class *cls,
679 struct class_device *parent,
681 struct device *device, char *fmt, ...)
684 struct class_device *class_dev = NULL;
685 int retval = -ENODEV;
687 if (cls == NULL || IS_ERR(cls))
690 class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
696 class_dev->devt = devt;
697 class_dev->dev = device;
698 class_dev->class = cls;
699 class_dev->parent = parent;
700 class_dev->release = class_device_create_release;
701 class_dev->uevent = class_device_create_uevent;
704 vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
706 retval = class_device_register(class_dev);
714 return ERR_PTR(retval);
717 void class_device_del(struct class_device *class_dev)
719 struct class *parent_class = class_dev->class;
720 struct class_device *parent_device = class_dev->parent;
721 struct class_interface *class_intf;
722 char *class_name = NULL;
725 down(&parent_class->sem);
726 list_del_init(&class_dev->node);
727 list_for_each_entry(class_intf, &parent_class->interfaces, node)
728 if (class_intf->remove)
729 class_intf->remove(class_dev, class_intf);
730 up(&parent_class->sem);
733 if (class_dev->dev) {
734 class_name = make_class_name(class_dev->class->name,
736 sysfs_remove_link(&class_dev->kobj, "device");
737 sysfs_remove_link(&class_dev->dev->kobj, class_name);
739 class_device_remove_file(class_dev, &class_dev->uevent_attr);
740 if (class_dev->devt_attr)
741 class_device_remove_file(class_dev, class_dev->devt_attr);
742 class_device_remove_attrs(class_dev);
743 class_device_remove_groups(class_dev);
745 kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
746 kobject_del(&class_dev->kobj);
748 class_device_put(parent_device);
749 class_put(parent_class);
753 void class_device_unregister(struct class_device *class_dev)
755 pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
756 class_dev->class_id);
757 class_device_del(class_dev);
758 class_device_put(class_dev);
762 * class_device_destroy - removes a class device that was created with class_device_create()
763 * @cls: the pointer to the struct class that this device was registered * with.
764 * @dev: the dev_t of the device that was previously registered.
766 * This call unregisters and cleans up a class device that was created with a
767 * call to class_device_create()
769 void class_device_destroy(struct class *cls, dev_t devt)
771 struct class_device *class_dev = NULL;
772 struct class_device *class_dev_tmp;
775 list_for_each_entry(class_dev_tmp, &cls->children, node) {
776 if (class_dev_tmp->devt == devt) {
777 class_dev = class_dev_tmp;
784 class_device_unregister(class_dev);
787 int class_device_rename(struct class_device *class_dev, char *new_name)
790 char *old_class_name = NULL, *new_class_name = NULL;
792 class_dev = class_device_get(class_dev);
796 pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
800 old_class_name = make_class_name(class_dev->class->name,
803 strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
805 error = kobject_rename(&class_dev->kobj, new_name);
807 if (class_dev->dev) {
808 new_class_name = make_class_name(class_dev->class->name,
810 sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
812 sysfs_remove_link(&class_dev->dev->kobj, old_class_name);
814 class_device_put(class_dev);
816 kfree(old_class_name);
817 kfree(new_class_name);
822 struct class_device * class_device_get(struct class_device *class_dev)
825 return to_class_dev(kobject_get(&class_dev->kobj));
829 void class_device_put(struct class_device *class_dev)
832 kobject_put(&class_dev->kobj);
836 int class_interface_register(struct class_interface *class_intf)
838 struct class *parent;
839 struct class_device *class_dev;
841 if (!class_intf || !class_intf->class)
844 parent = class_get(class_intf->class);
849 list_add_tail(&class_intf->node, &parent->interfaces);
850 if (class_intf->add) {
851 list_for_each_entry(class_dev, &parent->children, node)
852 class_intf->add(class_dev, class_intf);
859 void class_interface_unregister(struct class_interface *class_intf)
861 struct class * parent = class_intf->class;
862 struct class_device *class_dev;
868 list_del_init(&class_intf->node);
869 if (class_intf->remove) {
870 list_for_each_entry(class_dev, &parent->children, node)
871 class_intf->remove(class_dev, class_intf);
880 int __init classes_init(void)
884 retval = subsystem_register(&class_subsys);
888 /* ick, this is ugly, the things we go through to keep from showing up
890 subsystem_init(&class_obj_subsys);
891 if (!class_obj_subsys.kset.subsys)
892 class_obj_subsys.kset.subsys = &class_obj_subsys;
896 EXPORT_SYMBOL_GPL(class_create_file);
897 EXPORT_SYMBOL_GPL(class_remove_file);
898 EXPORT_SYMBOL_GPL(class_register);
899 EXPORT_SYMBOL_GPL(class_unregister);
900 EXPORT_SYMBOL_GPL(class_create);
901 EXPORT_SYMBOL_GPL(class_destroy);
903 EXPORT_SYMBOL_GPL(class_device_register);
904 EXPORT_SYMBOL_GPL(class_device_unregister);
905 EXPORT_SYMBOL_GPL(class_device_initialize);
906 EXPORT_SYMBOL_GPL(class_device_add);
907 EXPORT_SYMBOL_GPL(class_device_del);
908 EXPORT_SYMBOL_GPL(class_device_get);
909 EXPORT_SYMBOL_GPL(class_device_put);
910 EXPORT_SYMBOL_GPL(class_device_create);
911 EXPORT_SYMBOL_GPL(class_device_destroy);
912 EXPORT_SYMBOL_GPL(class_device_create_file);
913 EXPORT_SYMBOL_GPL(class_device_remove_file);
914 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
915 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
917 EXPORT_SYMBOL_GPL(class_interface_register);
918 EXPORT_SYMBOL_GPL(class_interface_unregister);