2 * drivers/base/core.c - core driver model code (device registration, etc)
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2006 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2006 Novell, Inc.
9 * This file is released under the GPLv2
13 #include <linux/device.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/string.h>
19 #include <linux/kdev_t.h>
21 #include <asm/semaphore.h>
24 #include "power/power.h"
26 int (*platform_notify
)(struct device
* dev
) = NULL
;
27 int (*platform_notify_remove
)(struct device
* dev
) = NULL
;
30 * sysfs bindings for devices.
34 * dev_driver_string - Return a device's driver name, if at all possible
35 * @dev: struct device to get the name of
37 * Will return the device's driver's name if it is bound to a device. If
38 * the device is not bound to a device, it will return the name of the bus
39 * it is attached to. If it is not attached to a bus either, an empty
40 * string will be returned.
42 const char *dev_driver_string(struct device
*dev
)
44 return dev
->driver
? dev
->driver
->name
:
45 (dev
->bus
? dev
->bus
->name
: "");
47 EXPORT_SYMBOL_GPL(dev_driver_string
);
49 #define to_dev(obj) container_of(obj, struct device, kobj)
50 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
53 dev_attr_show(struct kobject
* kobj
, struct attribute
* attr
, char * buf
)
55 struct device_attribute
* dev_attr
= to_dev_attr(attr
);
56 struct device
* dev
= to_dev(kobj
);
60 ret
= dev_attr
->show(dev
, dev_attr
, buf
);
65 dev_attr_store(struct kobject
* kobj
, struct attribute
* attr
,
66 const char * buf
, size_t count
)
68 struct device_attribute
* dev_attr
= to_dev_attr(attr
);
69 struct device
* dev
= to_dev(kobj
);
73 ret
= dev_attr
->store(dev
, dev_attr
, buf
, count
);
77 static struct sysfs_ops dev_sysfs_ops
= {
78 .show
= dev_attr_show
,
79 .store
= dev_attr_store
,
84 * device_release - free device structure.
85 * @kobj: device's kobject.
87 * This is called once the reference count for the object
88 * reaches 0. We forward the call to the device's release
89 * method, which should handle actually freeing the structure.
91 static void device_release(struct kobject
* kobj
)
93 struct device
* dev
= to_dev(kobj
);
97 else if (dev
->class && dev
->class->dev_release
)
98 dev
->class->dev_release(dev
);
100 printk(KERN_ERR
"Device '%s' does not have a release() function, "
101 "it is broken and must be fixed.\n",
107 static struct kobj_type ktype_device
= {
108 .release
= device_release
,
109 .sysfs_ops
= &dev_sysfs_ops
,
113 static int dev_uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
115 struct kobj_type
*ktype
= get_ktype(kobj
);
117 if (ktype
== &ktype_device
) {
118 struct device
*dev
= to_dev(kobj
);
127 static const char *dev_uevent_name(struct kset
*kset
, struct kobject
*kobj
)
129 struct device
*dev
= to_dev(kobj
);
132 return dev
->bus
->name
;
134 return dev
->class->name
;
138 static int dev_uevent(struct kset
*kset
, struct kobject
*kobj
, char **envp
,
139 int num_envp
, char *buffer
, int buffer_size
)
141 struct device
*dev
= to_dev(kobj
);
146 /* add the major/minor if present */
147 if (MAJOR(dev
->devt
)) {
148 add_uevent_var(envp
, num_envp
, &i
,
149 buffer
, buffer_size
, &length
,
150 "MAJOR=%u", MAJOR(dev
->devt
));
151 add_uevent_var(envp
, num_envp
, &i
,
152 buffer
, buffer_size
, &length
,
153 "MINOR=%u", MINOR(dev
->devt
));
156 /* add bus name (same as SUBSYSTEM, deprecated) */
158 add_uevent_var(envp
, num_envp
, &i
,
159 buffer
, buffer_size
, &length
,
160 "PHYSDEVBUS=%s", dev
->bus
->name
);
162 /* add driver name (PHYSDEV* values are deprecated)*/
164 add_uevent_var(envp
, num_envp
, &i
,
165 buffer
, buffer_size
, &length
,
166 "DRIVER=%s", dev
->driver
->name
);
167 add_uevent_var(envp
, num_envp
, &i
,
168 buffer
, buffer_size
, &length
,
169 "PHYSDEVDRIVER=%s", dev
->driver
->name
);
172 /* terminate, set to next free slot, shrink available space */
176 buffer
= &buffer
[length
];
177 buffer_size
-= length
;
179 if (dev
->bus
&& dev
->bus
->uevent
) {
180 /* have the bus specific function add its stuff */
181 retval
= dev
->bus
->uevent(dev
, envp
, num_envp
, buffer
, buffer_size
);
183 pr_debug ("%s - uevent() returned %d\n",
184 __FUNCTION__
, retval
);
188 if (dev
->class && dev
->class->dev_uevent
) {
189 /* have the class specific function add its stuff */
190 retval
= dev
->class->dev_uevent(dev
, envp
, num_envp
, buffer
, buffer_size
);
192 pr_debug("%s - dev_uevent() returned %d\n",
193 __FUNCTION__
, retval
);
200 static struct kset_uevent_ops device_uevent_ops
= {
201 .filter
= dev_uevent_filter
,
202 .name
= dev_uevent_name
,
203 .uevent
= dev_uevent
,
206 static ssize_t
store_uevent(struct device
*dev
, struct device_attribute
*attr
,
207 const char *buf
, size_t count
)
209 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
213 static int device_add_groups(struct device
*dev
)
219 for (i
= 0; dev
->groups
[i
]; i
++) {
220 error
= sysfs_create_group(&dev
->kobj
, dev
->groups
[i
]);
223 sysfs_remove_group(&dev
->kobj
, dev
->groups
[i
]);
232 static void device_remove_groups(struct device
*dev
)
236 for (i
= 0; dev
->groups
[i
]; i
++) {
237 sysfs_remove_group(&dev
->kobj
, dev
->groups
[i
]);
242 static int device_add_attrs(struct device
*dev
)
244 struct class *class = dev
->class;
251 if (class->dev_attrs
) {
252 for (i
= 0; attr_name(class->dev_attrs
[i
]); i
++) {
253 error
= device_create_file(dev
, &class->dev_attrs
[i
]);
260 device_remove_file(dev
, &class->dev_attrs
[i
]);
264 static void device_remove_attrs(struct device
*dev
)
266 struct class *class = dev
->class;
272 if (class->dev_attrs
) {
273 for (i
= 0; attr_name(class->dev_attrs
[i
]); i
++)
274 device_remove_file(dev
, &class->dev_attrs
[i
]);
279 static ssize_t
show_dev(struct device
*dev
, struct device_attribute
*attr
,
282 return print_dev_t(buf
, dev
->devt
);
286 * devices_subsys - structure to be registered with kobject core.
289 decl_subsys(devices
, &ktype_device
, &device_uevent_ops
);
293 * device_create_file - create sysfs attribute file for device.
295 * @attr: device attribute descriptor.
298 int device_create_file(struct device
* dev
, struct device_attribute
* attr
)
301 if (get_device(dev
)) {
302 error
= sysfs_create_file(&dev
->kobj
, &attr
->attr
);
309 * device_remove_file - remove sysfs attribute file.
311 * @attr: device attribute descriptor.
314 void device_remove_file(struct device
* dev
, struct device_attribute
* attr
)
316 if (get_device(dev
)) {
317 sysfs_remove_file(&dev
->kobj
, &attr
->attr
);
322 static void klist_children_get(struct klist_node
*n
)
324 struct device
*dev
= container_of(n
, struct device
, knode_parent
);
329 static void klist_children_put(struct klist_node
*n
)
331 struct device
*dev
= container_of(n
, struct device
, knode_parent
);
338 * device_initialize - init device structure.
341 * This prepares the device for use by other layers,
342 * including adding it to the device hierarchy.
343 * It is the first half of device_register(), if called by
344 * that, though it can also be called separately, so one
345 * may use @dev's fields (e.g. the refcount).
348 void device_initialize(struct device
*dev
)
350 kobj_set_kset_s(dev
, devices_subsys
);
351 kobject_init(&dev
->kobj
);
352 klist_init(&dev
->klist_children
, klist_children_get
,
354 INIT_LIST_HEAD(&dev
->dma_pools
);
355 INIT_LIST_HEAD(&dev
->node
);
356 init_MUTEX(&dev
->sem
);
357 device_init_wakeup(dev
, 0);
361 * device_add - add device to device hierarchy.
364 * This is part 2 of device_register(), though may be called
365 * separately _iff_ device_initialize() has been called separately.
367 * This adds it to the kobject hierarchy via kobject_add(), adds it
368 * to the global and sibling lists for the device, then
369 * adds it to the other relevant subsystems of the driver model.
371 int device_add(struct device
*dev
)
373 struct device
*parent
= NULL
;
374 char *class_name
= NULL
;
377 dev
= get_device(dev
);
378 if (!dev
|| !strlen(dev
->bus_id
))
381 /* if this is a class device, and has no parent, create one */
382 if ((dev
->class) && (dev
->parent
== NULL
)) {
383 error
= virtual_device_parent(dev
);
388 parent
= get_device(dev
->parent
);
390 pr_debug("DEV: registering device: ID = '%s'\n", dev
->bus_id
);
392 /* first, register with generic layer. */
393 kobject_set_name(&dev
->kobj
, "%s", dev
->bus_id
);
395 dev
->kobj
.parent
= &parent
->kobj
;
397 if ((error
= kobject_add(&dev
->kobj
)))
400 dev
->uevent_attr
.attr
.name
= "uevent";
401 dev
->uevent_attr
.attr
.mode
= S_IWUSR
;
403 dev
->uevent_attr
.attr
.owner
= dev
->driver
->owner
;
404 dev
->uevent_attr
.store
= store_uevent
;
405 device_create_file(dev
, &dev
->uevent_attr
);
407 if (MAJOR(dev
->devt
)) {
408 struct device_attribute
*attr
;
409 attr
= kzalloc(sizeof(*attr
), GFP_KERNEL
);
414 attr
->attr
.name
= "dev";
415 attr
->attr
.mode
= S_IRUGO
;
417 attr
->attr
.owner
= dev
->driver
->owner
;
418 attr
->show
= show_dev
;
419 error
= device_create_file(dev
, attr
);
425 dev
->devt_attr
= attr
;
429 sysfs_create_link(&dev
->kobj
, &dev
->class->subsys
.kset
.kobj
,
431 sysfs_create_link(&dev
->class->subsys
.kset
.kobj
, &dev
->kobj
,
434 sysfs_create_link(&dev
->kobj
, &dev
->parent
->kobj
, "device");
435 class_name
= make_class_name(dev
->class->name
, &dev
->kobj
);
436 sysfs_create_link(&dev
->parent
->kobj
, &dev
->kobj
, class_name
);
440 if ((error
= device_add_attrs(dev
)))
442 if ((error
= device_add_groups(dev
)))
444 if ((error
= device_pm_add(dev
)))
446 if ((error
= bus_add_device(dev
)))
448 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
449 bus_attach_device(dev
);
451 klist_add_tail(&dev
->knode_parent
, &parent
->klist_children
);
454 /* tie the class to the device */
455 down(&dev
->class->sem
);
456 list_add_tail(&dev
->node
, &dev
->class->devices
);
457 up(&dev
->class->sem
);
460 /* notify platform of device entry */
462 platform_notify(dev
);
468 device_pm_remove(dev
);
470 device_remove_groups(dev
);
472 device_remove_attrs(dev
);
474 if (dev
->devt_attr
) {
475 device_remove_file(dev
, dev
->devt_attr
);
476 kfree(dev
->devt_attr
);
479 kobject_uevent(&dev
->kobj
, KOBJ_REMOVE
);
480 kobject_del(&dev
->kobj
);
489 * device_register - register a device with the system.
490 * @dev: pointer to the device structure
492 * This happens in two clean steps - initialize the device
493 * and add it to the system. The two steps can be called
494 * separately, but this is the easiest and most common.
495 * I.e. you should only call the two helpers separately if
496 * have a clearly defined need to use and refcount the device
497 * before it is added to the hierarchy.
500 int device_register(struct device
*dev
)
502 device_initialize(dev
);
503 return device_add(dev
);
508 * get_device - increment reference count for device.
511 * This simply forwards the call to kobject_get(), though
512 * we do take care to provide for the case that we get a NULL
516 struct device
* get_device(struct device
* dev
)
518 return dev
? to_dev(kobject_get(&dev
->kobj
)) : NULL
;
523 * put_device - decrement reference count.
524 * @dev: device in question.
526 void put_device(struct device
* dev
)
529 kobject_put(&dev
->kobj
);
534 * device_del - delete device from system.
537 * This is the first part of the device unregistration
538 * sequence. This removes the device from the lists we control
539 * from here, has it removed from the other driver model
540 * subsystems it was added to in device_add(), and removes it
541 * from the kobject hierarchy.
543 * NOTE: this should be called manually _iff_ device_add() was
544 * also called manually.
547 void device_del(struct device
* dev
)
549 struct device
* parent
= dev
->parent
;
550 char *class_name
= NULL
;
553 klist_del(&dev
->knode_parent
);
555 device_remove_file(dev
, dev
->devt_attr
);
557 sysfs_remove_link(&dev
->kobj
, "subsystem");
558 sysfs_remove_link(&dev
->class->subsys
.kset
.kobj
, dev
->bus_id
);
559 class_name
= make_class_name(dev
->class->name
, &dev
->kobj
);
561 sysfs_remove_link(&dev
->kobj
, "device");
562 sysfs_remove_link(&dev
->parent
->kobj
, class_name
);
565 down(&dev
->class->sem
);
566 list_del_init(&dev
->node
);
567 up(&dev
->class->sem
);
569 device_remove_file(dev
, &dev
->uevent_attr
);
570 device_remove_groups(dev
);
571 device_remove_attrs(dev
);
573 /* Notify the platform of the removal, in case they
574 * need to do anything...
576 if (platform_notify_remove
)
577 platform_notify_remove(dev
);
578 bus_remove_device(dev
);
579 device_pm_remove(dev
);
580 kobject_uevent(&dev
->kobj
, KOBJ_REMOVE
);
581 kobject_del(&dev
->kobj
);
587 * device_unregister - unregister device from system.
588 * @dev: device going away.
590 * We do this in two parts, like we do device_register(). First,
591 * we remove it from all the subsystems with device_del(), then
592 * we decrement the reference count via put_device(). If that
593 * is the final reference count, the device will be cleaned up
594 * via device_release() above. Otherwise, the structure will
595 * stick around until the final reference to the device is dropped.
597 void device_unregister(struct device
* dev
)
599 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev
->bus_id
);
605 static struct device
* next_device(struct klist_iter
* i
)
607 struct klist_node
* n
= klist_next(i
);
608 return n
? container_of(n
, struct device
, knode_parent
) : NULL
;
612 * device_for_each_child - device child iterator.
613 * @parent: parent struct device.
614 * @data: data for the callback.
615 * @fn: function to be called for each device.
617 * Iterate over @parent's child devices, and call @fn for each,
620 * We check the return of @fn each time. If it returns anything
621 * other than 0, we break out and return that value.
623 int device_for_each_child(struct device
* parent
, void * data
,
624 int (*fn
)(struct device
*, void *))
627 struct device
* child
;
630 klist_iter_init(&parent
->klist_children
, &i
);
631 while ((child
= next_device(&i
)) && !error
)
632 error
= fn(child
, data
);
637 int __init
devices_init(void)
639 return subsystem_register(&devices_subsys
);
642 EXPORT_SYMBOL_GPL(device_for_each_child
);
644 EXPORT_SYMBOL_GPL(device_initialize
);
645 EXPORT_SYMBOL_GPL(device_add
);
646 EXPORT_SYMBOL_GPL(device_register
);
648 EXPORT_SYMBOL_GPL(device_del
);
649 EXPORT_SYMBOL_GPL(device_unregister
);
650 EXPORT_SYMBOL_GPL(get_device
);
651 EXPORT_SYMBOL_GPL(put_device
);
653 EXPORT_SYMBOL_GPL(device_create_file
);
654 EXPORT_SYMBOL_GPL(device_remove_file
);
657 static void device_create_release(struct device
*dev
)
659 pr_debug("%s called for %s\n", __FUNCTION__
, dev
->bus_id
);
664 * device_create - creates a device and registers it with sysfs
665 * @class: pointer to the struct class that this device should be registered to
666 * @parent: pointer to the parent struct device of this new device, if any
667 * @devt: the dev_t for the char device to be added
668 * @fmt: string for the device's name
670 * This function can be used by char device classes. A struct device
671 * will be created in sysfs, registered to the specified class.
673 * A "dev" file will be created, showing the dev_t for the device, if
674 * the dev_t is not 0,0.
675 * If a pointer to a parent struct device is passed in, the newly created
676 * struct device will be a child of that device in sysfs.
677 * The pointer to the struct device will be returned from the call.
678 * Any further sysfs files that might be required can be created using this
681 * Note: the struct class passed to this function must have previously
682 * been created with a call to class_create().
684 struct device
*device_create(struct class *class, struct device
*parent
,
685 dev_t devt
, const char *fmt
, ...)
688 struct device
*dev
= NULL
;
689 int retval
= -ENODEV
;
691 if (class == NULL
|| IS_ERR(class))
694 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
702 dev
->parent
= parent
;
703 dev
->release
= device_create_release
;
706 vsnprintf(dev
->bus_id
, BUS_ID_SIZE
, fmt
, args
);
708 retval
= device_register(dev
);
716 return ERR_PTR(retval
);
718 EXPORT_SYMBOL_GPL(device_create
);
721 * device_destroy - removes a device that was created with device_create()
722 * @class: pointer to the struct class that this device was registered with
723 * @devt: the dev_t of the device that was previously registered
725 * This call unregisters and cleans up a device that was created with a
726 * call to device_create().
728 void device_destroy(struct class *class, dev_t devt
)
730 struct device
*dev
= NULL
;
731 struct device
*dev_tmp
;
734 list_for_each_entry(dev_tmp
, &class->devices
, node
) {
735 if (dev_tmp
->devt
== devt
) {
743 device_unregister(dev
);
745 EXPORT_SYMBOL_GPL(device_destroy
);
748 * device_rename - renames a device
749 * @dev: the pointer to the struct device to be renamed
750 * @new_name: the new name of the device
752 int device_rename(struct device
*dev
, char *new_name
)
754 char *old_class_name
= NULL
;
755 char *new_class_name
= NULL
;
756 char *old_symlink_name
= NULL
;
759 dev
= get_device(dev
);
763 pr_debug("DEVICE: renaming '%s' to '%s'\n", dev
->bus_id
, new_name
);
765 if ((dev
->class) && (dev
->parent
))
766 old_class_name
= make_class_name(dev
->class->name
, &dev
->kobj
);
769 old_symlink_name
= kmalloc(BUS_ID_SIZE
, GFP_KERNEL
);
770 if (!old_symlink_name
)
772 strlcpy(old_symlink_name
, dev
->bus_id
, BUS_ID_SIZE
);
775 strlcpy(dev
->bus_id
, new_name
, BUS_ID_SIZE
);
777 error
= kobject_rename(&dev
->kobj
, new_name
);
779 if (old_class_name
) {
780 new_class_name
= make_class_name(dev
->class->name
, &dev
->kobj
);
781 if (new_class_name
) {
782 sysfs_create_link(&dev
->parent
->kobj
, &dev
->kobj
,
784 sysfs_remove_link(&dev
->parent
->kobj
, old_class_name
);
788 sysfs_remove_link(&dev
->class->subsys
.kset
.kobj
,
790 sysfs_create_link(&dev
->class->subsys
.kset
.kobj
, &dev
->kobj
,
795 kfree(old_class_name
);
796 kfree(new_class_name
);
797 kfree(old_symlink_name
);