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);
303 kfree(cd->devt_attr);
304 cd->devt_attr = NULL;
310 printk(KERN_ERR "Device class '%s' does not have a release() function, "
311 "it is broken and must be fixed.\n",
317 static struct kobj_type ktype_class_device = {
318 .sysfs_ops = &class_dev_sysfs_ops,
319 .release = class_dev_release,
322 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
324 struct kobj_type *ktype = get_ktype(kobj);
326 if (ktype == &ktype_class_device) {
327 struct class_device *class_dev = to_class_dev(kobj);
328 if (class_dev->class)
334 static const char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
336 struct class_device *class_dev = to_class_dev(kobj);
338 return class_dev->class->name;
341 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
342 int num_envp, char *buffer, int buffer_size)
344 struct class_device *class_dev = to_class_dev(kobj);
349 pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
351 if (class_dev->dev) {
352 /* add physical device, backing this device */
353 struct device *dev = class_dev->dev;
354 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
356 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
357 &length, "PHYSDEVPATH=%s", path);
361 add_hotplug_env_var(envp, num_envp, &i,
362 buffer, buffer_size, &length,
363 "PHYSDEVBUS=%s", dev->bus->name);
366 add_hotplug_env_var(envp, num_envp, &i,
367 buffer, buffer_size, &length,
368 "PHYSDEVDRIVER=%s", dev->driver->name);
371 if (MAJOR(class_dev->devt)) {
372 add_hotplug_env_var(envp, num_envp, &i,
373 buffer, buffer_size, &length,
374 "MAJOR=%u", MAJOR(class_dev->devt));
376 add_hotplug_env_var(envp, num_envp, &i,
377 buffer, buffer_size, &length,
378 "MINOR=%u", MINOR(class_dev->devt));
381 /* terminate, set to next free slot, shrink available space */
385 buffer = &buffer[length];
386 buffer_size -= length;
388 if (class_dev->class->hotplug) {
389 /* have the bus specific function add its stuff */
390 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
391 buffer, buffer_size);
393 pr_debug ("%s - hotplug() returned %d\n",
394 __FUNCTION__, retval);
401 static struct kset_hotplug_ops class_hotplug_ops = {
402 .filter = class_hotplug_filter,
403 .name = class_hotplug_name,
404 .hotplug = class_hotplug,
407 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
410 static int class_device_add_attrs(struct class_device * cd)
414 struct class * cls = cd->class;
416 if (cls->class_dev_attrs) {
417 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
418 error = class_device_create_file(cd,
419 &cls->class_dev_attrs[i]);
428 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
432 static void class_device_remove_attrs(struct class_device * cd)
435 struct class * cls = cd->class;
437 if (cls->class_dev_attrs) {
438 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
439 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
443 static ssize_t show_dev(struct class_device *class_dev, char *buf)
445 return print_dev_t(buf, class_dev->devt);
448 void class_device_initialize(struct class_device *class_dev)
450 kobj_set_kset_s(class_dev, class_obj_subsys);
451 kobject_init(&class_dev->kobj);
452 INIT_LIST_HEAD(&class_dev->node);
455 static char *make_class_name(struct class_device *class_dev)
460 size = strlen(class_dev->class->name) +
461 strlen(kobject_name(&class_dev->kobj)) + 2;
463 name = kmalloc(size, GFP_KERNEL);
465 return ERR_PTR(-ENOMEM);
467 strcpy(name, class_dev->class->name);
469 strcat(name, kobject_name(&class_dev->kobj));
473 int class_device_add(struct class_device *class_dev)
475 struct class * parent = NULL;
476 struct class_interface * class_intf;
477 char *class_name = NULL;
480 class_dev = class_device_get(class_dev);
484 if (!strlen(class_dev->class_id)) {
489 parent = class_get(class_dev->class);
491 pr_debug("CLASS: registering class device: ID = '%s'\n",
492 class_dev->class_id);
494 /* first, register with generic layer. */
495 kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
497 class_dev->kobj.parent = &parent->subsys.kset.kobj;
499 if ((error = kobject_add(&class_dev->kobj)))
502 /* add the needed attributes to this device */
503 if (MAJOR(class_dev->devt)) {
504 struct class_device_attribute *attr;
505 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
508 kobject_del(&class_dev->kobj);
511 memset(attr, sizeof(*attr), 0x00);
512 attr->attr.name = "dev";
513 attr->attr.mode = S_IRUGO;
514 attr->attr.owner = parent->owner;
515 attr->show = show_dev;
517 class_device_create_file(class_dev, attr);
518 class_dev->devt_attr = attr;
521 class_device_add_attrs(class_dev);
522 if (class_dev->dev) {
523 class_name = make_class_name(class_dev);
524 sysfs_create_link(&class_dev->kobj,
525 &class_dev->dev->kobj, "device");
526 sysfs_create_link(&class_dev->dev->kobj, &class_dev->kobj,
530 /* notify any interfaces this device is now here */
533 list_add_tail(&class_dev->node, &parent->children);
534 list_for_each_entry(class_intf, &parent->interfaces, node)
536 class_intf->add(class_dev);
539 kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
544 class_device_put(class_dev);
549 int class_device_register(struct class_device *class_dev)
551 class_device_initialize(class_dev);
552 return class_device_add(class_dev);
556 * class_device_create - creates a class device and registers it with sysfs
557 * @cs: pointer to the struct class that this device should be registered to.
558 * @dev: the dev_t for the char device to be added.
559 * @device: a pointer to a struct device that is assiociated with this class device.
560 * @fmt: string for the class device's name
562 * This function can be used by char device classes. A struct
563 * class_device will be created in sysfs, registered to the specified
564 * class. A "dev" file will be created, showing the dev_t for the
565 * device. The pointer to the struct class_device will be returned from
566 * the call. Any further sysfs files that might be required can be
567 * created using this pointer.
569 * Note: the struct class passed to this function must have previously
570 * been created with a call to class_create().
572 struct class_device *class_device_create(struct class *cls, dev_t devt,
573 struct device *device, char *fmt, ...)
576 struct class_device *class_dev = NULL;
577 int retval = -ENODEV;
579 if (cls == NULL || IS_ERR(cls))
582 class_dev = kmalloc(sizeof(struct class_device), GFP_KERNEL);
587 memset(class_dev, 0x00, sizeof(struct class_device));
589 class_dev->devt = devt;
590 class_dev->dev = device;
591 class_dev->class = cls;
594 vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
596 retval = class_device_register(class_dev);
604 return ERR_PTR(retval);
607 void class_device_del(struct class_device *class_dev)
609 struct class * parent = class_dev->class;
610 struct class_interface * class_intf;
611 char *class_name = NULL;
615 list_del_init(&class_dev->node);
616 list_for_each_entry(class_intf, &parent->interfaces, node)
617 if (class_intf->remove)
618 class_intf->remove(class_dev);
622 if (class_dev->dev) {
623 class_name = make_class_name(class_dev);
624 sysfs_remove_link(&class_dev->kobj, "device");
625 sysfs_remove_link(&class_dev->dev->kobj, class_name);
627 if (class_dev->devt_attr)
628 class_device_remove_file(class_dev, class_dev->devt_attr);
629 class_device_remove_attrs(class_dev);
631 kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
632 kobject_del(&class_dev->kobj);
639 void class_device_unregister(struct class_device *class_dev)
641 pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
642 class_dev->class_id);
643 class_device_del(class_dev);
644 class_device_put(class_dev);
648 * class_device_destroy - removes a class device that was created with class_device_create()
649 * @cls: the pointer to the struct class that this device was registered * with.
650 * @dev: the dev_t of the device that was previously registered.
652 * This call unregisters and cleans up a class device that was created with a
653 * call to class_device_create()
655 void class_device_destroy(struct class *cls, dev_t devt)
657 struct class_device *class_dev = NULL;
658 struct class_device *class_dev_tmp;
661 list_for_each_entry(class_dev_tmp, &cls->children, node) {
662 if (class_dev_tmp->devt == devt) {
663 class_dev = class_dev_tmp;
670 class_device_unregister(class_dev);
673 int class_device_rename(struct class_device *class_dev, char *new_name)
677 class_dev = class_device_get(class_dev);
681 pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
684 strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
686 error = kobject_rename(&class_dev->kobj, new_name);
688 class_device_put(class_dev);
693 struct class_device * class_device_get(struct class_device *class_dev)
696 return to_class_dev(kobject_get(&class_dev->kobj));
700 void class_device_put(struct class_device *class_dev)
702 kobject_put(&class_dev->kobj);
706 int class_interface_register(struct class_interface *class_intf)
708 struct class *parent;
709 struct class_device *class_dev;
711 if (!class_intf || !class_intf->class)
714 parent = class_get(class_intf->class);
719 list_add_tail(&class_intf->node, &parent->interfaces);
720 if (class_intf->add) {
721 list_for_each_entry(class_dev, &parent->children, node)
722 class_intf->add(class_dev);
729 void class_interface_unregister(struct class_interface *class_intf)
731 struct class * parent = class_intf->class;
732 struct class_device *class_dev;
738 list_del_init(&class_intf->node);
739 if (class_intf->remove) {
740 list_for_each_entry(class_dev, &parent->children, node)
741 class_intf->remove(class_dev);
750 int __init classes_init(void)
754 retval = subsystem_register(&class_subsys);
758 /* ick, this is ugly, the things we go through to keep from showing up
760 subsystem_init(&class_obj_subsys);
761 if (!class_obj_subsys.kset.subsys)
762 class_obj_subsys.kset.subsys = &class_obj_subsys;
766 EXPORT_SYMBOL_GPL(class_create_file);
767 EXPORT_SYMBOL_GPL(class_remove_file);
768 EXPORT_SYMBOL_GPL(class_register);
769 EXPORT_SYMBOL_GPL(class_unregister);
770 EXPORT_SYMBOL_GPL(class_get);
771 EXPORT_SYMBOL_GPL(class_put);
772 EXPORT_SYMBOL_GPL(class_create);
773 EXPORT_SYMBOL_GPL(class_destroy);
775 EXPORT_SYMBOL_GPL(class_device_register);
776 EXPORT_SYMBOL_GPL(class_device_unregister);
777 EXPORT_SYMBOL_GPL(class_device_initialize);
778 EXPORT_SYMBOL_GPL(class_device_add);
779 EXPORT_SYMBOL_GPL(class_device_del);
780 EXPORT_SYMBOL_GPL(class_device_get);
781 EXPORT_SYMBOL_GPL(class_device_put);
782 EXPORT_SYMBOL_GPL(class_device_create);
783 EXPORT_SYMBOL_GPL(class_device_destroy);
784 EXPORT_SYMBOL_GPL(class_device_create_file);
785 EXPORT_SYMBOL_GPL(class_device_remove_file);
786 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
787 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
789 EXPORT_SYMBOL_GPL(class_interface_register);
790 EXPORT_SYMBOL_GPL(class_interface_unregister);