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->devices);
146 INIT_LIST_HEAD(&cls->interfaces);
147 init_MUTEX(&cls->sem);
148 error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
152 subsys_set_kset(cls, class_subsys);
154 error = subsystem_register(&cls->subsys);
156 error = add_class_attrs(class_get(cls));
162 void class_unregister(struct class * cls)
164 pr_debug("device class '%s': unregistering\n", cls->name);
165 remove_class_attrs(cls);
166 subsystem_unregister(&cls->subsys);
169 static void class_create_release(struct class *cls)
171 pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
175 static void class_device_create_release(struct class_device *class_dev)
177 pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
181 /* needed to allow these devices to have parent class devices */
182 static int class_device_create_uevent(struct class_device *class_dev,
183 char **envp, int num_envp,
184 char *buffer, int buffer_size)
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, 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 * @cs: 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);
315 kfree(cd->devt_attr);
316 cd->devt_attr = NULL;
320 else if (cls->release)
323 printk(KERN_ERR "Class Device '%s' does not have a release() function, "
324 "it is broken and must be fixed.\n",
330 static struct kobj_type ktype_class_device = {
331 .sysfs_ops = &class_dev_sysfs_ops,
332 .release = class_dev_release,
335 static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
337 struct kobj_type *ktype = get_ktype(kobj);
339 if (ktype == &ktype_class_device) {
340 struct class_device *class_dev = to_class_dev(kobj);
341 if (class_dev->class)
347 static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
349 struct class_device *class_dev = to_class_dev(kobj);
351 return class_dev->class->name;
354 static int class_uevent(struct kset *kset, struct kobject *kobj, char **envp,
355 int num_envp, char *buffer, int buffer_size)
357 struct class_device *class_dev = to_class_dev(kobj);
362 pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
364 if (class_dev->dev) {
365 /* add physical device, backing this device */
366 struct device *dev = class_dev->dev;
367 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
369 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
370 &length, "PHYSDEVPATH=%s", path);
374 add_uevent_var(envp, num_envp, &i,
375 buffer, buffer_size, &length,
376 "PHYSDEVBUS=%s", dev->bus->name);
379 add_uevent_var(envp, num_envp, &i,
380 buffer, buffer_size, &length,
381 "PHYSDEVDRIVER=%s", dev->driver->name);
384 if (MAJOR(class_dev->devt)) {
385 add_uevent_var(envp, num_envp, &i,
386 buffer, buffer_size, &length,
387 "MAJOR=%u", MAJOR(class_dev->devt));
389 add_uevent_var(envp, num_envp, &i,
390 buffer, buffer_size, &length,
391 "MINOR=%u", MINOR(class_dev->devt));
394 /* terminate, set to next free slot, shrink available space */
398 buffer = &buffer[length];
399 buffer_size -= length;
401 if (class_dev->uevent) {
402 /* have the class device specific function add its stuff */
403 retval = class_dev->uevent(class_dev, envp, num_envp,
404 buffer, buffer_size);
406 pr_debug("class_dev->uevent() returned %d\n", retval);
407 } else if (class_dev->class->uevent) {
408 /* have the class specific function add its stuff */
409 retval = class_dev->class->uevent(class_dev, envp, num_envp,
410 buffer, buffer_size);
412 pr_debug("class->uevent() returned %d\n", retval);
418 static struct kset_uevent_ops class_uevent_ops = {
419 .filter = class_uevent_filter,
420 .name = class_uevent_name,
421 .uevent = class_uevent,
424 static decl_subsys(class_obj, &ktype_class_device, &class_uevent_ops);
427 static int class_device_add_attrs(struct class_device * cd)
431 struct class * cls = cd->class;
433 if (cls->class_dev_attrs) {
434 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
435 error = class_device_create_file(cd,
436 &cls->class_dev_attrs[i]);
445 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
449 static void class_device_remove_attrs(struct class_device * cd)
452 struct class * cls = cd->class;
454 if (cls->class_dev_attrs) {
455 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
456 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
460 static int class_device_add_groups(struct class_device * cd)
466 for (i = 0; cd->groups[i]; i++) {
467 error = sysfs_create_group(&cd->kobj, cd->groups[i]);
470 sysfs_remove_group(&cd->kobj, cd->groups[i]);
479 static void class_device_remove_groups(struct class_device * cd)
483 for (i = 0; cd->groups[i]; i++) {
484 sysfs_remove_group(&cd->kobj, cd->groups[i]);
489 static ssize_t show_dev(struct class_device *class_dev, char *buf)
491 return print_dev_t(buf, class_dev->devt);
494 static ssize_t store_uevent(struct class_device *class_dev,
495 const char *buf, size_t count)
497 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
501 void class_device_initialize(struct class_device *class_dev)
503 kobj_set_kset_s(class_dev, class_obj_subsys);
504 kobject_init(&class_dev->kobj);
505 INIT_LIST_HEAD(&class_dev->node);
508 char *make_class_name(const char *name, struct kobject *kobj)
513 size = strlen(name) + strlen(kobject_name(kobj)) + 2;
515 class_name = kmalloc(size, GFP_KERNEL);
517 return ERR_PTR(-ENOMEM);
519 strcpy(class_name, name);
520 strcat(class_name, ":");
521 strcat(class_name, kobject_name(kobj));
525 int class_device_add(struct class_device *class_dev)
527 struct class *parent_class = NULL;
528 struct class_device *parent_class_dev = NULL;
529 struct class_interface *class_intf;
530 char *class_name = NULL;
533 class_dev = class_device_get(class_dev);
537 if (!strlen(class_dev->class_id))
540 parent_class = class_get(class_dev->class);
544 parent_class_dev = class_device_get(class_dev->parent);
546 pr_debug("CLASS: registering class device: ID = '%s'\n",
547 class_dev->class_id);
549 /* first, register with generic layer. */
550 error = kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
554 if (parent_class_dev)
555 class_dev->kobj.parent = &parent_class_dev->kobj;
557 class_dev->kobj.parent = &parent_class->subsys.kset.kobj;
559 error = kobject_add(&class_dev->kobj);
563 /* add the needed attributes to this device */
564 class_dev->uevent_attr.attr.name = "uevent";
565 class_dev->uevent_attr.attr.mode = S_IWUSR;
566 class_dev->uevent_attr.attr.owner = parent_class->owner;
567 class_dev->uevent_attr.store = store_uevent;
568 error = class_device_create_file(class_dev, &class_dev->uevent_attr);
572 if (MAJOR(class_dev->devt)) {
573 struct class_device_attribute *attr;
574 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
579 attr->attr.name = "dev";
580 attr->attr.mode = S_IRUGO;
581 attr->attr.owner = parent_class->owner;
582 attr->show = show_dev;
583 error = class_device_create_file(class_dev, attr);
589 class_dev->devt_attr = attr;
592 error = class_device_add_attrs(class_dev);
596 if (class_dev->dev) {
597 class_name = make_class_name(class_dev->class->name,
599 error = sysfs_create_link(&class_dev->kobj,
600 &class_dev->dev->kobj, "device");
603 error = sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
609 error = class_device_add_groups(class_dev);
613 kobject_uevent(&class_dev->kobj, KOBJ_ADD);
615 /* notify any interfaces this device is now here */
616 down(&parent_class->sem);
617 list_add_tail(&class_dev->node, &parent_class->children);
618 list_for_each_entry(class_intf, &parent_class->interfaces, node) {
620 class_intf->add(class_dev, class_intf);
622 up(&parent_class->sem);
628 sysfs_remove_link(&class_dev->kobj, class_name);
631 sysfs_remove_link(&class_dev->kobj, "device");
633 class_device_remove_attrs(class_dev);
635 if (class_dev->devt_attr)
636 class_device_remove_file(class_dev, class_dev->devt_attr);
638 class_device_remove_file(class_dev, &class_dev->uevent_attr);
640 kobject_del(&class_dev->kobj);
643 class_device_put(parent_class_dev);
644 class_put(parent_class);
646 class_device_put(class_dev);
651 int class_device_register(struct class_device *class_dev)
653 class_device_initialize(class_dev);
654 return class_device_add(class_dev);
658 * class_device_create - creates a class device and registers it with sysfs
659 * @cs: pointer to the struct class that this device should be registered to.
660 * @parent: pointer to the parent struct class_device of this new device, if any.
661 * @dev: the dev_t for the char device to be added.
662 * @device: a pointer to a struct device that is assiociated with this class device.
663 * @fmt: string for the class device's name
665 * This function can be used by char device classes. A struct
666 * class_device will be created in sysfs, registered to the specified
668 * A "dev" file will be created, showing the dev_t for the device, if
669 * the dev_t is not 0,0.
670 * If a pointer to a parent struct class_device is passed in, the newly
671 * created struct class_device will be a child of that device in sysfs.
672 * The pointer to the struct class_device will be returned from the
673 * call. Any further sysfs files that might be required can be created
674 * using this pointer.
676 * Note: the struct class passed to this function must have previously
677 * been created with a call to class_create().
679 struct class_device *class_device_create(struct class *cls,
680 struct class_device *parent,
682 struct device *device, char *fmt, ...)
685 struct class_device *class_dev = NULL;
686 int retval = -ENODEV;
688 if (cls == NULL || IS_ERR(cls))
691 class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
697 class_dev->devt = devt;
698 class_dev->dev = device;
699 class_dev->class = cls;
700 class_dev->parent = parent;
701 class_dev->release = class_device_create_release;
702 class_dev->uevent = class_device_create_uevent;
705 vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
707 retval = class_device_register(class_dev);
715 return ERR_PTR(retval);
718 void class_device_del(struct class_device *class_dev)
720 struct class *parent_class = class_dev->class;
721 struct class_device *parent_device = class_dev->parent;
722 struct class_interface *class_intf;
723 char *class_name = NULL;
726 down(&parent_class->sem);
727 list_del_init(&class_dev->node);
728 list_for_each_entry(class_intf, &parent_class->interfaces, node)
729 if (class_intf->remove)
730 class_intf->remove(class_dev, class_intf);
731 up(&parent_class->sem);
734 if (class_dev->dev) {
735 class_name = make_class_name(class_dev->class->name,
737 sysfs_remove_link(&class_dev->kobj, "device");
738 sysfs_remove_link(&class_dev->dev->kobj, class_name);
740 class_device_remove_file(class_dev, &class_dev->uevent_attr);
741 if (class_dev->devt_attr)
742 class_device_remove_file(class_dev, class_dev->devt_attr);
743 class_device_remove_attrs(class_dev);
744 class_device_remove_groups(class_dev);
746 kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
747 kobject_del(&class_dev->kobj);
749 class_device_put(parent_device);
750 class_put(parent_class);
754 void class_device_unregister(struct class_device *class_dev)
756 pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
757 class_dev->class_id);
758 class_device_del(class_dev);
759 class_device_put(class_dev);
763 * class_device_destroy - removes a class device that was created with class_device_create()
764 * @cls: the pointer to the struct class that this device was registered * with.
765 * @dev: the dev_t of the device that was previously registered.
767 * This call unregisters and cleans up a class device that was created with a
768 * call to class_device_create()
770 void class_device_destroy(struct class *cls, dev_t devt)
772 struct class_device *class_dev = NULL;
773 struct class_device *class_dev_tmp;
776 list_for_each_entry(class_dev_tmp, &cls->children, node) {
777 if (class_dev_tmp->devt == devt) {
778 class_dev = class_dev_tmp;
785 class_device_unregister(class_dev);
788 int class_device_rename(struct class_device *class_dev, char *new_name)
791 char *old_class_name = NULL, *new_class_name = NULL;
793 class_dev = class_device_get(class_dev);
797 pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
801 old_class_name = make_class_name(class_dev->class->name,
804 strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
806 error = kobject_rename(&class_dev->kobj, new_name);
808 if (class_dev->dev) {
809 new_class_name = make_class_name(class_dev->class->name,
811 sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
813 sysfs_remove_link(&class_dev->dev->kobj, old_class_name);
815 class_device_put(class_dev);
817 kfree(old_class_name);
818 kfree(new_class_name);
823 struct class_device * class_device_get(struct class_device *class_dev)
826 return to_class_dev(kobject_get(&class_dev->kobj));
830 void class_device_put(struct class_device *class_dev)
833 kobject_put(&class_dev->kobj);
837 int class_interface_register(struct class_interface *class_intf)
839 struct class *parent;
840 struct class_device *class_dev;
842 if (!class_intf || !class_intf->class)
845 parent = class_get(class_intf->class);
850 list_add_tail(&class_intf->node, &parent->interfaces);
851 if (class_intf->add) {
852 list_for_each_entry(class_dev, &parent->children, node)
853 class_intf->add(class_dev, class_intf);
860 void class_interface_unregister(struct class_interface *class_intf)
862 struct class * parent = class_intf->class;
863 struct class_device *class_dev;
869 list_del_init(&class_intf->node);
870 if (class_intf->remove) {
871 list_for_each_entry(class_dev, &parent->children, node)
872 class_intf->remove(class_dev, class_intf);
881 int __init classes_init(void)
885 retval = subsystem_register(&class_subsys);
889 /* ick, this is ugly, the things we go through to keep from showing up
891 subsystem_init(&class_obj_subsys);
892 if (!class_obj_subsys.kset.subsys)
893 class_obj_subsys.kset.subsys = &class_obj_subsys;
897 EXPORT_SYMBOL_GPL(class_create_file);
898 EXPORT_SYMBOL_GPL(class_remove_file);
899 EXPORT_SYMBOL_GPL(class_register);
900 EXPORT_SYMBOL_GPL(class_unregister);
901 EXPORT_SYMBOL_GPL(class_create);
902 EXPORT_SYMBOL_GPL(class_destroy);
904 EXPORT_SYMBOL_GPL(class_device_register);
905 EXPORT_SYMBOL_GPL(class_device_unregister);
906 EXPORT_SYMBOL_GPL(class_device_initialize);
907 EXPORT_SYMBOL_GPL(class_device_add);
908 EXPORT_SYMBOL_GPL(class_device_del);
909 EXPORT_SYMBOL_GPL(class_device_get);
910 EXPORT_SYMBOL_GPL(class_device_put);
911 EXPORT_SYMBOL_GPL(class_device_create);
912 EXPORT_SYMBOL_GPL(class_device_destroy);
913 EXPORT_SYMBOL_GPL(class_device_create_file);
914 EXPORT_SYMBOL_GPL(class_device_remove_file);
915 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
916 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
918 EXPORT_SYMBOL_GPL(class_interface_register);
919 EXPORT_SYMBOL_GPL(class_interface_unregister);