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
7 * This file is released under the GPLv2
11 #include <linux/device.h>
12 #include <linux/err.h>
13 #include <linux/init.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/kdev_t.h>
19 #include <asm/semaphore.h>
22 #include "power/power.h"
24 int (*platform_notify
)(struct device
* dev
) = NULL
;
25 int (*platform_notify_remove
)(struct device
* dev
) = NULL
;
28 * sysfs bindings for devices.
32 * dev_driver_string - Return a device's driver name, if at all possible
33 * @dev: struct device to get the name of
35 * Will return the device's driver's name if it is bound to a device. If
36 * the device is not bound to a device, it will return the name of the bus
37 * it is attached to. If it is not attached to a bus either, an empty
38 * string will be returned.
40 const char *dev_driver_string(struct device
*dev
)
42 return dev
->driver
? dev
->driver
->name
:
43 (dev
->bus
? dev
->bus
->name
: "");
45 EXPORT_SYMBOL_GPL(dev_driver_string
);
47 #define to_dev(obj) container_of(obj, struct device, kobj)
48 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
51 dev_attr_show(struct kobject
* kobj
, struct attribute
* attr
, char * buf
)
53 struct device_attribute
* dev_attr
= to_dev_attr(attr
);
54 struct device
* dev
= to_dev(kobj
);
58 ret
= dev_attr
->show(dev
, dev_attr
, buf
);
63 dev_attr_store(struct kobject
* kobj
, struct attribute
* attr
,
64 const char * buf
, size_t count
)
66 struct device_attribute
* dev_attr
= to_dev_attr(attr
);
67 struct device
* dev
= to_dev(kobj
);
71 ret
= dev_attr
->store(dev
, dev_attr
, buf
, count
);
75 static struct sysfs_ops dev_sysfs_ops
= {
76 .show
= dev_attr_show
,
77 .store
= dev_attr_store
,
82 * device_release - free device structure.
83 * @kobj: device's kobject.
85 * This is called once the reference count for the object
86 * reaches 0. We forward the call to the device's release
87 * method, which should handle actually freeing the structure.
89 static void device_release(struct kobject
* kobj
)
91 struct device
* dev
= to_dev(kobj
);
96 printk(KERN_ERR
"Device '%s' does not have a release() function, "
97 "it is broken and must be fixed.\n",
103 static struct kobj_type ktype_device
= {
104 .release
= device_release
,
105 .sysfs_ops
= &dev_sysfs_ops
,
109 static int dev_uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
111 struct kobj_type
*ktype
= get_ktype(kobj
);
113 if (ktype
== &ktype_device
) {
114 struct device
*dev
= to_dev(kobj
);
123 static const char *dev_uevent_name(struct kset
*kset
, struct kobject
*kobj
)
125 struct device
*dev
= to_dev(kobj
);
128 return dev
->bus
->name
;
130 return dev
->class->name
;
134 static int dev_uevent(struct kset
*kset
, struct kobject
*kobj
, char **envp
,
135 int num_envp
, char *buffer
, int buffer_size
)
137 struct device
*dev
= to_dev(kobj
);
142 /* add the major/minor if present */
143 if (MAJOR(dev
->devt
)) {
144 add_uevent_var(envp
, num_envp
, &i
,
145 buffer
, buffer_size
, &length
,
146 "MAJOR=%u", MAJOR(dev
->devt
));
147 add_uevent_var(envp
, num_envp
, &i
,
148 buffer
, buffer_size
, &length
,
149 "MINOR=%u", MINOR(dev
->devt
));
152 /* add bus name of physical device */
154 add_uevent_var(envp
, num_envp
, &i
,
155 buffer
, buffer_size
, &length
,
156 "PHYSDEVBUS=%s", dev
->bus
->name
);
158 /* add driver name of physical device */
160 add_uevent_var(envp
, num_envp
, &i
,
161 buffer
, buffer_size
, &length
,
162 "PHYSDEVDRIVER=%s", dev
->driver
->name
);
164 /* terminate, set to next free slot, shrink available space */
168 buffer
= &buffer
[length
];
169 buffer_size
-= length
;
171 if (dev
->bus
&& dev
->bus
->uevent
) {
172 /* have the bus specific function add its stuff */
173 retval
= dev
->bus
->uevent(dev
, envp
, num_envp
, buffer
, buffer_size
);
175 pr_debug ("%s - uevent() returned %d\n",
176 __FUNCTION__
, retval
);
183 static struct kset_uevent_ops device_uevent_ops
= {
184 .filter
= dev_uevent_filter
,
185 .name
= dev_uevent_name
,
186 .uevent
= dev_uevent
,
189 static ssize_t
store_uevent(struct device
*dev
, struct device_attribute
*attr
,
190 const char *buf
, size_t count
)
192 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
196 static ssize_t
show_dev(struct device
*dev
, struct device_attribute
*attr
,
199 return print_dev_t(buf
, dev
->devt
);
203 * devices_subsys - structure to be registered with kobject core.
206 decl_subsys(devices
, &ktype_device
, &device_uevent_ops
);
210 * device_create_file - create sysfs attribute file for device.
212 * @attr: device attribute descriptor.
215 int device_create_file(struct device
* dev
, struct device_attribute
* attr
)
218 if (get_device(dev
)) {
219 error
= sysfs_create_file(&dev
->kobj
, &attr
->attr
);
226 * device_remove_file - remove sysfs attribute file.
228 * @attr: device attribute descriptor.
231 void device_remove_file(struct device
* dev
, struct device_attribute
* attr
)
233 if (get_device(dev
)) {
234 sysfs_remove_file(&dev
->kobj
, &attr
->attr
);
239 static void klist_children_get(struct klist_node
*n
)
241 struct device
*dev
= container_of(n
, struct device
, knode_parent
);
246 static void klist_children_put(struct klist_node
*n
)
248 struct device
*dev
= container_of(n
, struct device
, knode_parent
);
255 * device_initialize - init device structure.
258 * This prepares the device for use by other layers,
259 * including adding it to the device hierarchy.
260 * It is the first half of device_register(), if called by
261 * that, though it can also be called separately, so one
262 * may use @dev's fields (e.g. the refcount).
265 void device_initialize(struct device
*dev
)
267 kobj_set_kset_s(dev
, devices_subsys
);
268 kobject_init(&dev
->kobj
);
269 klist_init(&dev
->klist_children
, klist_children_get
,
271 INIT_LIST_HEAD(&dev
->dma_pools
);
272 INIT_LIST_HEAD(&dev
->node
);
273 init_MUTEX(&dev
->sem
);
274 device_init_wakeup(dev
, 0);
278 * device_add - add device to device hierarchy.
281 * This is part 2 of device_register(), though may be called
282 * separately _iff_ device_initialize() has been called separately.
284 * This adds it to the kobject hierarchy via kobject_add(), adds it
285 * to the global and sibling lists for the device, then
286 * adds it to the other relevant subsystems of the driver model.
288 int device_add(struct device
*dev
)
290 struct device
*parent
= NULL
;
291 char *class_name
= NULL
;
294 dev
= get_device(dev
);
295 if (!dev
|| !strlen(dev
->bus_id
))
298 parent
= get_device(dev
->parent
);
300 pr_debug("DEV: registering device: ID = '%s'\n", dev
->bus_id
);
302 /* first, register with generic layer. */
303 kobject_set_name(&dev
->kobj
, "%s", dev
->bus_id
);
305 dev
->kobj
.parent
= &parent
->kobj
;
307 if ((error
= kobject_add(&dev
->kobj
)))
310 dev
->uevent_attr
.attr
.name
= "uevent";
311 dev
->uevent_attr
.attr
.mode
= S_IWUSR
;
313 dev
->uevent_attr
.attr
.owner
= dev
->driver
->owner
;
314 dev
->uevent_attr
.store
= store_uevent
;
315 device_create_file(dev
, &dev
->uevent_attr
);
317 if (MAJOR(dev
->devt
)) {
318 struct device_attribute
*attr
;
319 attr
= kzalloc(sizeof(*attr
), GFP_KERNEL
);
324 attr
->attr
.name
= "dev";
325 attr
->attr
.mode
= S_IRUGO
;
327 attr
->attr
.owner
= dev
->driver
->owner
;
328 attr
->show
= show_dev
;
329 error
= device_create_file(dev
, attr
);
335 dev
->devt_attr
= attr
;
339 sysfs_create_link(&dev
->kobj
, &dev
->class->subsys
.kset
.kobj
,
341 sysfs_create_link(&dev
->class->subsys
.kset
.kobj
, &dev
->kobj
,
344 sysfs_create_link(&dev
->kobj
, &dev
->parent
->kobj
, "device");
345 class_name
= make_class_name(dev
->class->name
, &dev
->kobj
);
346 sysfs_create_link(&dev
->parent
->kobj
, &dev
->kobj
, class_name
);
349 if ((error
= device_pm_add(dev
)))
351 if ((error
= bus_add_device(dev
)))
353 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
354 bus_attach_device(dev
);
356 klist_add_tail(&dev
->knode_parent
, &parent
->klist_children
);
359 /* tie the class to the device */
360 down(&dev
->class->sem
);
361 list_add_tail(&dev
->node
, &dev
->class->devices
);
362 up(&dev
->class->sem
);
365 /* notify platform of device entry */
367 platform_notify(dev
);
373 device_pm_remove(dev
);
375 if (dev
->devt_attr
) {
376 device_remove_file(dev
, dev
->devt_attr
);
377 kfree(dev
->devt_attr
);
380 kobject_uevent(&dev
->kobj
, KOBJ_REMOVE
);
381 kobject_del(&dev
->kobj
);
390 * device_register - register a device with the system.
391 * @dev: pointer to the device structure
393 * This happens in two clean steps - initialize the device
394 * and add it to the system. The two steps can be called
395 * separately, but this is the easiest and most common.
396 * I.e. you should only call the two helpers separately if
397 * have a clearly defined need to use and refcount the device
398 * before it is added to the hierarchy.
401 int device_register(struct device
*dev
)
403 device_initialize(dev
);
404 return device_add(dev
);
409 * get_device - increment reference count for device.
412 * This simply forwards the call to kobject_get(), though
413 * we do take care to provide for the case that we get a NULL
417 struct device
* get_device(struct device
* dev
)
419 return dev
? to_dev(kobject_get(&dev
->kobj
)) : NULL
;
424 * put_device - decrement reference count.
425 * @dev: device in question.
427 void put_device(struct device
* dev
)
430 kobject_put(&dev
->kobj
);
435 * device_del - delete device from system.
438 * This is the first part of the device unregistration
439 * sequence. This removes the device from the lists we control
440 * from here, has it removed from the other driver model
441 * subsystems it was added to in device_add(), and removes it
442 * from the kobject hierarchy.
444 * NOTE: this should be called manually _iff_ device_add() was
445 * also called manually.
448 void device_del(struct device
* dev
)
450 struct device
* parent
= dev
->parent
;
451 char *class_name
= NULL
;
454 klist_del(&dev
->knode_parent
);
456 device_remove_file(dev
, dev
->devt_attr
);
458 sysfs_remove_link(&dev
->kobj
, "subsystem");
459 sysfs_remove_link(&dev
->class->subsys
.kset
.kobj
, dev
->bus_id
);
460 class_name
= make_class_name(dev
->class->name
, &dev
->kobj
);
461 sysfs_remove_link(&dev
->kobj
, "device");
462 sysfs_remove_link(&dev
->parent
->kobj
, class_name
);
464 down(&dev
->class->sem
);
465 list_del_init(&dev
->node
);
466 up(&dev
->class->sem
);
468 device_remove_file(dev
, &dev
->uevent_attr
);
470 /* Notify the platform of the removal, in case they
471 * need to do anything...
473 if (platform_notify_remove
)
474 platform_notify_remove(dev
);
475 bus_remove_device(dev
);
476 device_pm_remove(dev
);
477 kobject_uevent(&dev
->kobj
, KOBJ_REMOVE
);
478 kobject_del(&dev
->kobj
);
484 * device_unregister - unregister device from system.
485 * @dev: device going away.
487 * We do this in two parts, like we do device_register(). First,
488 * we remove it from all the subsystems with device_del(), then
489 * we decrement the reference count via put_device(). If that
490 * is the final reference count, the device will be cleaned up
491 * via device_release() above. Otherwise, the structure will
492 * stick around until the final reference to the device is dropped.
494 void device_unregister(struct device
* dev
)
496 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev
->bus_id
);
502 static struct device
* next_device(struct klist_iter
* i
)
504 struct klist_node
* n
= klist_next(i
);
505 return n
? container_of(n
, struct device
, knode_parent
) : NULL
;
509 * device_for_each_child - device child iterator.
510 * @parent: parent struct device.
511 * @data: data for the callback.
512 * @fn: function to be called for each device.
514 * Iterate over @parent's child devices, and call @fn for each,
517 * We check the return of @fn each time. If it returns anything
518 * other than 0, we break out and return that value.
520 int device_for_each_child(struct device
* parent
, void * data
,
521 int (*fn
)(struct device
*, void *))
524 struct device
* child
;
527 klist_iter_init(&parent
->klist_children
, &i
);
528 while ((child
= next_device(&i
)) && !error
)
529 error
= fn(child
, data
);
534 int __init
devices_init(void)
536 return subsystem_register(&devices_subsys
);
539 EXPORT_SYMBOL_GPL(device_for_each_child
);
541 EXPORT_SYMBOL_GPL(device_initialize
);
542 EXPORT_SYMBOL_GPL(device_add
);
543 EXPORT_SYMBOL_GPL(device_register
);
545 EXPORT_SYMBOL_GPL(device_del
);
546 EXPORT_SYMBOL_GPL(device_unregister
);
547 EXPORT_SYMBOL_GPL(get_device
);
548 EXPORT_SYMBOL_GPL(put_device
);
550 EXPORT_SYMBOL_GPL(device_create_file
);
551 EXPORT_SYMBOL_GPL(device_remove_file
);
554 static void device_create_release(struct device
*dev
)
556 pr_debug("%s called for %s\n", __FUNCTION__
, dev
->bus_id
);
561 * device_create - creates a device and registers it with sysfs
562 * @class: pointer to the struct class that this device should be registered to
563 * @parent: pointer to the parent struct device of this new device, if any
564 * @devt: the dev_t for the char device to be added
565 * @fmt: string for the device's name
567 * This function can be used by char device classes. A struct device
568 * will be created in sysfs, registered to the specified class.
570 * A "dev" file will be created, showing the dev_t for the device, if
571 * the dev_t is not 0,0.
572 * If a pointer to a parent struct device is passed in, the newly created
573 * struct device will be a child of that device in sysfs.
574 * The pointer to the struct device will be returned from the call.
575 * Any further sysfs files that might be required can be created using this
578 * Note: the struct class passed to this function must have previously
579 * been created with a call to class_create().
581 struct device
*device_create(struct class *class, struct device
*parent
,
582 dev_t devt
, char *fmt
, ...)
585 struct device
*dev
= NULL
;
586 int retval
= -ENODEV
;
588 if (class == NULL
|| IS_ERR(class))
590 if (parent
== NULL
) {
591 printk(KERN_WARNING
"%s does not work yet for NULL parents\n", __FUNCTION__
);
595 dev
= kzalloc(sizeof(*dev
), GFP_KERNEL
);
603 dev
->parent
= parent
;
604 dev
->release
= device_create_release
;
607 vsnprintf(dev
->bus_id
, BUS_ID_SIZE
, fmt
, args
);
609 retval
= device_register(dev
);
617 return ERR_PTR(retval
);
619 EXPORT_SYMBOL_GPL(device_create
);
622 * device_destroy - removes a device that was created with device_create()
623 * @class: pointer to the struct class that this device was registered with
624 * @devt: the dev_t of the device that was previously registered
626 * This call unregisters and cleans up a device that was created with a
627 * call to device_create().
629 void device_destroy(struct class *class, dev_t devt
)
631 struct device
*dev
= NULL
;
632 struct device
*dev_tmp
;
635 list_for_each_entry(dev_tmp
, &class->devices
, node
) {
636 if (dev_tmp
->devt
== devt
) {
644 device_unregister(dev
);
646 EXPORT_SYMBOL_GPL(device_destroy
);