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 struct class * class_get(struct class * cls
)
97 return container_of(subsys_get(&cls
->subsys
), struct class, subsys
);
101 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_hotplug(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_hotplug_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_hotplug_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_hotplug(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_hotplug_env_var(envp
, num_envp
, &i
, buffer
, buffer_size
,
369 &length
, "PHYSDEVPATH=%s", path
);
373 add_hotplug_env_var(envp
, num_envp
, &i
,
374 buffer
, buffer_size
, &length
,
375 "PHYSDEVBUS=%s", dev
->bus
->name
);
378 add_hotplug_env_var(envp
, num_envp
, &i
,
379 buffer
, buffer_size
, &length
,
380 "PHYSDEVDRIVER=%s", dev
->driver
->name
);
383 if (MAJOR(class_dev
->devt
)) {
384 add_hotplug_env_var(envp
, num_envp
, &i
,
385 buffer
, buffer_size
, &length
,
386 "MAJOR=%u", MAJOR(class_dev
->devt
));
388 add_hotplug_env_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
->hotplug
) {
401 /* have the class device specific function add its stuff */
402 retval
= class_dev
->hotplug(class_dev
, envp
, num_envp
,
403 buffer
, buffer_size
);
405 pr_debug("class_dev->hotplug() returned %d\n", retval
);
406 } else if (class_dev
->class->hotplug
) {
407 /* have the class specific function add its stuff */
408 retval
= class_dev
->class->hotplug(class_dev
, envp
, num_envp
,
409 buffer
, buffer_size
);
411 pr_debug("class->hotplug() returned %d\n", retval
);
417 static struct kset_hotplug_ops class_hotplug_ops
= {
418 .filter
= class_hotplug_filter
,
419 .name
= class_hotplug_name
,
420 .hotplug
= class_hotplug
,
423 static decl_subsys(class_obj
, &ktype_class_device
, &class_hotplug_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 ssize_t
show_dev(struct class_device
*class_dev
, char *buf
)
461 return print_dev_t(buf
, class_dev
->devt
);
464 static ssize_t
store_uevent(struct class_device
*class_dev
,
465 const char *buf
, size_t count
)
467 kobject_hotplug(&class_dev
->kobj
, KOBJ_ADD
);
471 void class_device_initialize(struct class_device
*class_dev
)
473 kobj_set_kset_s(class_dev
, class_obj_subsys
);
474 kobject_init(&class_dev
->kobj
);
475 INIT_LIST_HEAD(&class_dev
->node
);
478 static char *make_class_name(struct class_device
*class_dev
)
483 size
= strlen(class_dev
->class->name
) +
484 strlen(kobject_name(&class_dev
->kobj
)) + 2;
486 name
= kmalloc(size
, GFP_KERNEL
);
488 return ERR_PTR(-ENOMEM
);
490 strcpy(name
, class_dev
->class->name
);
492 strcat(name
, kobject_name(&class_dev
->kobj
));
496 int class_device_add(struct class_device
*class_dev
)
498 struct class *parent_class
= NULL
;
499 struct class_device
*parent_class_dev
= NULL
;
500 struct class_interface
*class_intf
;
501 char *class_name
= NULL
;
504 class_dev
= class_device_get(class_dev
);
508 if (!strlen(class_dev
->class_id
))
511 parent_class
= class_get(class_dev
->class);
514 parent_class_dev
= class_device_get(class_dev
->parent
);
516 pr_debug("CLASS: registering class device: ID = '%s'\n",
517 class_dev
->class_id
);
519 /* first, register with generic layer. */
520 kobject_set_name(&class_dev
->kobj
, "%s", class_dev
->class_id
);
521 if (parent_class_dev
)
522 class_dev
->kobj
.parent
= &parent_class_dev
->kobj
;
524 class_dev
->kobj
.parent
= &parent_class
->subsys
.kset
.kobj
;
526 error
= kobject_add(&class_dev
->kobj
);
530 /* add the needed attributes to this device */
531 class_dev
->uevent_attr
.attr
.name
= "uevent";
532 class_dev
->uevent_attr
.attr
.mode
= S_IWUSR
;
533 class_dev
->uevent_attr
.attr
.owner
= parent_class
->owner
;
534 class_dev
->uevent_attr
.store
= store_uevent
;
535 class_device_create_file(class_dev
, &class_dev
->uevent_attr
);
537 if (MAJOR(class_dev
->devt
)) {
538 struct class_device_attribute
*attr
;
539 attr
= kzalloc(sizeof(*attr
), GFP_KERNEL
);
542 kobject_del(&class_dev
->kobj
);
545 attr
->attr
.name
= "dev";
546 attr
->attr
.mode
= S_IRUGO
;
547 attr
->attr
.owner
= parent_class
->owner
;
548 attr
->show
= show_dev
;
549 class_device_create_file(class_dev
, attr
);
550 class_dev
->devt_attr
= attr
;
553 class_device_add_attrs(class_dev
);
554 if (class_dev
->dev
) {
555 class_name
= make_class_name(class_dev
);
556 sysfs_create_link(&class_dev
->kobj
,
557 &class_dev
->dev
->kobj
, "device");
558 sysfs_create_link(&class_dev
->dev
->kobj
, &class_dev
->kobj
,
562 kobject_hotplug(&class_dev
->kobj
, KOBJ_ADD
);
564 /* notify any interfaces this device is now here */
566 down(&parent_class
->sem
);
567 list_add_tail(&class_dev
->node
, &parent_class
->children
);
568 list_for_each_entry(class_intf
, &parent_class
->interfaces
, node
)
570 class_intf
->add(class_dev
, class_intf
);
571 up(&parent_class
->sem
);
576 class_put(parent_class
);
577 class_device_put(parent_class_dev
);
579 class_device_put(class_dev
);
584 int class_device_register(struct class_device
*class_dev
)
586 class_device_initialize(class_dev
);
587 return class_device_add(class_dev
);
591 * class_device_create - creates a class device and registers it with sysfs
592 * @cs: pointer to the struct class that this device should be registered to.
593 * @parent: pointer to the parent struct class_device of this new device, if any.
594 * @dev: the dev_t for the char device to be added.
595 * @device: a pointer to a struct device that is assiociated with this class device.
596 * @fmt: string for the class device's name
598 * This function can be used by char device classes. A struct
599 * class_device will be created in sysfs, registered to the specified
601 * A "dev" file will be created, showing the dev_t for the device, if
602 * the dev_t is not 0,0.
603 * If a pointer to a parent struct class_device is passed in, the newly
604 * created struct class_device will be a child of that device in sysfs.
605 * The pointer to the struct class_device will be returned from the
606 * call. Any further sysfs files that might be required can be created
607 * using this pointer.
609 * Note: the struct class passed to this function must have previously
610 * been created with a call to class_create().
612 struct class_device
*class_device_create(struct class *cls
,
613 struct class_device
*parent
,
615 struct device
*device
, char *fmt
, ...)
618 struct class_device
*class_dev
= NULL
;
619 int retval
= -ENODEV
;
621 if (cls
== NULL
|| IS_ERR(cls
))
624 class_dev
= kzalloc(sizeof(*class_dev
), GFP_KERNEL
);
630 class_dev
->devt
= devt
;
631 class_dev
->dev
= device
;
632 class_dev
->class = cls
;
633 class_dev
->parent
= parent
;
634 class_dev
->release
= class_device_create_release
;
635 class_dev
->hotplug
= class_device_create_hotplug
;
638 vsnprintf(class_dev
->class_id
, BUS_ID_SIZE
, fmt
, args
);
640 retval
= class_device_register(class_dev
);
648 return ERR_PTR(retval
);
651 void class_device_del(struct class_device
*class_dev
)
653 struct class *parent_class
= class_dev
->class;
654 struct class_device
*parent_device
= class_dev
->parent
;
655 struct class_interface
*class_intf
;
656 char *class_name
= NULL
;
659 down(&parent_class
->sem
);
660 list_del_init(&class_dev
->node
);
661 list_for_each_entry(class_intf
, &parent_class
->interfaces
, node
)
662 if (class_intf
->remove
)
663 class_intf
->remove(class_dev
, class_intf
);
664 up(&parent_class
->sem
);
667 if (class_dev
->dev
) {
668 class_name
= make_class_name(class_dev
);
669 sysfs_remove_link(&class_dev
->kobj
, "device");
670 sysfs_remove_link(&class_dev
->dev
->kobj
, class_name
);
672 class_device_remove_file(class_dev
, &class_dev
->uevent_attr
);
673 if (class_dev
->devt_attr
)
674 class_device_remove_file(class_dev
, class_dev
->devt_attr
);
675 class_device_remove_attrs(class_dev
);
677 kobject_hotplug(&class_dev
->kobj
, KOBJ_REMOVE
);
678 kobject_del(&class_dev
->kobj
);
680 class_device_put(parent_device
);
681 class_put(parent_class
);
685 void class_device_unregister(struct class_device
*class_dev
)
687 pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
688 class_dev
->class_id
);
689 class_device_del(class_dev
);
690 class_device_put(class_dev
);
694 * class_device_destroy - removes a class device that was created with class_device_create()
695 * @cls: the pointer to the struct class that this device was registered * with.
696 * @dev: the dev_t of the device that was previously registered.
698 * This call unregisters and cleans up a class device that was created with a
699 * call to class_device_create()
701 void class_device_destroy(struct class *cls
, dev_t devt
)
703 struct class_device
*class_dev
= NULL
;
704 struct class_device
*class_dev_tmp
;
707 list_for_each_entry(class_dev_tmp
, &cls
->children
, node
) {
708 if (class_dev_tmp
->devt
== devt
) {
709 class_dev
= class_dev_tmp
;
716 class_device_unregister(class_dev
);
719 int class_device_rename(struct class_device
*class_dev
, char *new_name
)
722 char *old_class_name
= NULL
, *new_class_name
= NULL
;
724 class_dev
= class_device_get(class_dev
);
728 pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev
->class_id
,
732 old_class_name
= make_class_name(class_dev
);
734 strlcpy(class_dev
->class_id
, new_name
, KOBJ_NAME_LEN
);
736 error
= kobject_rename(&class_dev
->kobj
, new_name
);
738 if (class_dev
->dev
) {
739 new_class_name
= make_class_name(class_dev
);
740 sysfs_create_link(&class_dev
->dev
->kobj
, &class_dev
->kobj
,
742 sysfs_remove_link(&class_dev
->dev
->kobj
, old_class_name
);
744 class_device_put(class_dev
);
746 kfree(old_class_name
);
747 kfree(new_class_name
);
752 struct class_device
* class_device_get(struct class_device
*class_dev
)
755 return to_class_dev(kobject_get(&class_dev
->kobj
));
759 void class_device_put(struct class_device
*class_dev
)
762 kobject_put(&class_dev
->kobj
);
766 int class_interface_register(struct class_interface
*class_intf
)
768 struct class *parent
;
769 struct class_device
*class_dev
;
771 if (!class_intf
|| !class_intf
->class)
774 parent
= class_get(class_intf
->class);
779 list_add_tail(&class_intf
->node
, &parent
->interfaces
);
780 if (class_intf
->add
) {
781 list_for_each_entry(class_dev
, &parent
->children
, node
)
782 class_intf
->add(class_dev
, class_intf
);
789 void class_interface_unregister(struct class_interface
*class_intf
)
791 struct class * parent
= class_intf
->class;
792 struct class_device
*class_dev
;
798 list_del_init(&class_intf
->node
);
799 if (class_intf
->remove
) {
800 list_for_each_entry(class_dev
, &parent
->children
, node
)
801 class_intf
->remove(class_dev
, class_intf
);
810 int __init
classes_init(void)
814 retval
= subsystem_register(&class_subsys
);
818 /* ick, this is ugly, the things we go through to keep from showing up
820 subsystem_init(&class_obj_subsys
);
821 if (!class_obj_subsys
.kset
.subsys
)
822 class_obj_subsys
.kset
.subsys
= &class_obj_subsys
;
826 EXPORT_SYMBOL_GPL(class_create_file
);
827 EXPORT_SYMBOL_GPL(class_remove_file
);
828 EXPORT_SYMBOL_GPL(class_register
);
829 EXPORT_SYMBOL_GPL(class_unregister
);
830 EXPORT_SYMBOL_GPL(class_get
);
831 EXPORT_SYMBOL_GPL(class_put
);
832 EXPORT_SYMBOL_GPL(class_create
);
833 EXPORT_SYMBOL_GPL(class_destroy
);
835 EXPORT_SYMBOL_GPL(class_device_register
);
836 EXPORT_SYMBOL_GPL(class_device_unregister
);
837 EXPORT_SYMBOL_GPL(class_device_initialize
);
838 EXPORT_SYMBOL_GPL(class_device_add
);
839 EXPORT_SYMBOL_GPL(class_device_del
);
840 EXPORT_SYMBOL_GPL(class_device_get
);
841 EXPORT_SYMBOL_GPL(class_device_put
);
842 EXPORT_SYMBOL_GPL(class_device_create
);
843 EXPORT_SYMBOL_GPL(class_device_destroy
);
844 EXPORT_SYMBOL_GPL(class_device_create_file
);
845 EXPORT_SYMBOL_GPL(class_device_remove_file
);
846 EXPORT_SYMBOL_GPL(class_device_create_bin_file
);
847 EXPORT_SYMBOL_GPL(class_device_remove_bin_file
);
849 EXPORT_SYMBOL_GPL(class_interface_register
);
850 EXPORT_SYMBOL_GPL(class_interface_unregister
);