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/config.h>
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/string.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.
31 #define to_dev(obj) container_of(obj, struct device, kobj)
32 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
35 dev_attr_show(struct kobject
* kobj
, struct attribute
* attr
, char * buf
)
37 struct device_attribute
* dev_attr
= to_dev_attr(attr
);
38 struct device
* dev
= to_dev(kobj
);
42 ret
= dev_attr
->show(dev
, dev_attr
, buf
);
47 dev_attr_store(struct kobject
* kobj
, struct attribute
* attr
,
48 const char * buf
, size_t count
)
50 struct device_attribute
* dev_attr
= to_dev_attr(attr
);
51 struct device
* dev
= to_dev(kobj
);
55 ret
= dev_attr
->store(dev
, dev_attr
, buf
, count
);
59 static struct sysfs_ops dev_sysfs_ops
= {
60 .show
= dev_attr_show
,
61 .store
= dev_attr_store
,
66 * device_release - free device structure.
67 * @kobj: device's kobject.
69 * This is called once the reference count for the object
70 * reaches 0. We forward the call to the device's release
71 * method, which should handle actually freeing the structure.
73 static void device_release(struct kobject
* kobj
)
75 struct device
* dev
= to_dev(kobj
);
80 printk(KERN_ERR
"Device '%s' does not have a release() function, "
81 "it is broken and must be fixed.\n",
87 static struct kobj_type ktype_device
= {
88 .release
= device_release
,
89 .sysfs_ops
= &dev_sysfs_ops
,
93 static int dev_uevent_filter(struct kset
*kset
, struct kobject
*kobj
)
95 struct kobj_type
*ktype
= get_ktype(kobj
);
97 if (ktype
== &ktype_device
) {
98 struct device
*dev
= to_dev(kobj
);
105 static const char *dev_uevent_name(struct kset
*kset
, struct kobject
*kobj
)
107 struct device
*dev
= to_dev(kobj
);
109 return dev
->bus
->name
;
112 static int dev_uevent(struct kset
*kset
, struct kobject
*kobj
, char **envp
,
113 int num_envp
, char *buffer
, int buffer_size
)
115 struct device
*dev
= to_dev(kobj
);
120 /* add bus name of physical device */
122 add_uevent_var(envp
, num_envp
, &i
,
123 buffer
, buffer_size
, &length
,
124 "PHYSDEVBUS=%s", dev
->bus
->name
);
126 /* add driver name of physical device */
128 add_uevent_var(envp
, num_envp
, &i
,
129 buffer
, buffer_size
, &length
,
130 "PHYSDEVDRIVER=%s", dev
->driver
->name
);
132 /* terminate, set to next free slot, shrink available space */
136 buffer
= &buffer
[length
];
137 buffer_size
-= length
;
139 if (dev
->bus
&& dev
->bus
->uevent
) {
140 /* have the bus specific function add its stuff */
141 retval
= dev
->bus
->uevent(dev
, envp
, num_envp
, buffer
, buffer_size
);
143 pr_debug ("%s - uevent() returned %d\n",
144 __FUNCTION__
, retval
);
151 static struct kset_uevent_ops device_uevent_ops
= {
152 .filter
= dev_uevent_filter
,
153 .name
= dev_uevent_name
,
154 .uevent
= dev_uevent
,
157 static ssize_t
store_uevent(struct device
*dev
, struct device_attribute
*attr
,
158 const char *buf
, size_t count
)
160 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
165 * devices_subsys - structure to be registered with kobject core.
168 decl_subsys(devices
, &ktype_device
, &device_uevent_ops
);
172 * device_create_file - create sysfs attribute file for device.
174 * @attr: device attribute descriptor.
177 int device_create_file(struct device
* dev
, struct device_attribute
* attr
)
180 if (get_device(dev
)) {
181 error
= sysfs_create_file(&dev
->kobj
, &attr
->attr
);
188 * device_remove_file - remove sysfs attribute file.
190 * @attr: device attribute descriptor.
193 void device_remove_file(struct device
* dev
, struct device_attribute
* attr
)
195 if (get_device(dev
)) {
196 sysfs_remove_file(&dev
->kobj
, &attr
->attr
);
201 static void klist_children_get(struct klist_node
*n
)
203 struct device
*dev
= container_of(n
, struct device
, knode_parent
);
208 static void klist_children_put(struct klist_node
*n
)
210 struct device
*dev
= container_of(n
, struct device
, knode_parent
);
217 * device_initialize - init device structure.
220 * This prepares the device for use by other layers,
221 * including adding it to the device hierarchy.
222 * It is the first half of device_register(), if called by
223 * that, though it can also be called separately, so one
224 * may use @dev's fields (e.g. the refcount).
227 void device_initialize(struct device
*dev
)
229 kobj_set_kset_s(dev
, devices_subsys
);
230 kobject_init(&dev
->kobj
);
231 klist_init(&dev
->klist_children
, klist_children_get
,
233 INIT_LIST_HEAD(&dev
->dma_pools
);
234 init_MUTEX(&dev
->sem
);
235 device_init_wakeup(dev
, 0);
239 * device_add - add device to device hierarchy.
242 * This is part 2 of device_register(), though may be called
243 * separately _iff_ device_initialize() has been called separately.
245 * This adds it to the kobject hierarchy via kobject_add(), adds it
246 * to the global and sibling lists for the device, then
247 * adds it to the other relevant subsystems of the driver model.
249 int device_add(struct device
*dev
)
251 struct device
*parent
= NULL
;
254 dev
= get_device(dev
);
255 if (!dev
|| !strlen(dev
->bus_id
))
258 parent
= get_device(dev
->parent
);
260 pr_debug("DEV: registering device: ID = '%s'\n", dev
->bus_id
);
262 /* first, register with generic layer. */
263 kobject_set_name(&dev
->kobj
, "%s", dev
->bus_id
);
265 dev
->kobj
.parent
= &parent
->kobj
;
267 if ((error
= kobject_add(&dev
->kobj
)))
270 dev
->uevent_attr
.attr
.name
= "uevent";
271 dev
->uevent_attr
.attr
.mode
= S_IWUSR
;
273 dev
->uevent_attr
.attr
.owner
= dev
->driver
->owner
;
274 dev
->uevent_attr
.store
= store_uevent
;
275 device_create_file(dev
, &dev
->uevent_attr
);
277 if ((error
= device_pm_add(dev
)))
279 if ((error
= bus_add_device(dev
)))
281 kobject_uevent(&dev
->kobj
, KOBJ_ADD
);
282 bus_attach_device(dev
);
284 klist_add_tail(&dev
->knode_parent
, &parent
->klist_children
);
286 /* notify platform of device entry */
288 platform_notify(dev
);
293 device_pm_remove(dev
);
295 kobject_uevent(&dev
->kobj
, KOBJ_REMOVE
);
296 kobject_del(&dev
->kobj
);
305 * device_register - register a device with the system.
306 * @dev: pointer to the device structure
308 * This happens in two clean steps - initialize the device
309 * and add it to the system. The two steps can be called
310 * separately, but this is the easiest and most common.
311 * I.e. you should only call the two helpers separately if
312 * have a clearly defined need to use and refcount the device
313 * before it is added to the hierarchy.
316 int device_register(struct device
*dev
)
318 device_initialize(dev
);
319 return device_add(dev
);
324 * get_device - increment reference count for device.
327 * This simply forwards the call to kobject_get(), though
328 * we do take care to provide for the case that we get a NULL
332 struct device
* get_device(struct device
* dev
)
334 return dev
? to_dev(kobject_get(&dev
->kobj
)) : NULL
;
339 * put_device - decrement reference count.
340 * @dev: device in question.
342 void put_device(struct device
* dev
)
345 kobject_put(&dev
->kobj
);
350 * device_del - delete device from system.
353 * This is the first part of the device unregistration
354 * sequence. This removes the device from the lists we control
355 * from here, has it removed from the other driver model
356 * subsystems it was added to in device_add(), and removes it
357 * from the kobject hierarchy.
359 * NOTE: this should be called manually _iff_ device_add() was
360 * also called manually.
363 void device_del(struct device
* dev
)
365 struct device
* parent
= dev
->parent
;
368 klist_del(&dev
->knode_parent
);
369 device_remove_file(dev
, &dev
->uevent_attr
);
371 /* Notify the platform of the removal, in case they
372 * need to do anything...
374 if (platform_notify_remove
)
375 platform_notify_remove(dev
);
376 bus_remove_device(dev
);
377 device_pm_remove(dev
);
378 kobject_uevent(&dev
->kobj
, KOBJ_REMOVE
);
379 kobject_del(&dev
->kobj
);
385 * device_unregister - unregister device from system.
386 * @dev: device going away.
388 * We do this in two parts, like we do device_register(). First,
389 * we remove it from all the subsystems with device_del(), then
390 * we decrement the reference count via put_device(). If that
391 * is the final reference count, the device will be cleaned up
392 * via device_release() above. Otherwise, the structure will
393 * stick around until the final reference to the device is dropped.
395 void device_unregister(struct device
* dev
)
397 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev
->bus_id
);
403 static struct device
* next_device(struct klist_iter
* i
)
405 struct klist_node
* n
= klist_next(i
);
406 return n
? container_of(n
, struct device
, knode_parent
) : NULL
;
410 * device_for_each_child - device child iterator.
411 * @parent: parent struct device.
412 * @data: data for the callback.
413 * @fn: function to be called for each device.
415 * Iterate over @parent's child devices, and call @fn for each,
418 * We check the return of @fn each time. If it returns anything
419 * other than 0, we break out and return that value.
421 int device_for_each_child(struct device
* parent
, void * data
,
422 int (*fn
)(struct device
*, void *))
425 struct device
* child
;
428 klist_iter_init(&parent
->klist_children
, &i
);
429 while ((child
= next_device(&i
)) && !error
)
430 error
= fn(child
, data
);
435 int __init
devices_init(void)
437 return subsystem_register(&devices_subsys
);
440 EXPORT_SYMBOL_GPL(device_for_each_child
);
442 EXPORT_SYMBOL_GPL(device_initialize
);
443 EXPORT_SYMBOL_GPL(device_add
);
444 EXPORT_SYMBOL_GPL(device_register
);
446 EXPORT_SYMBOL_GPL(device_del
);
447 EXPORT_SYMBOL_GPL(device_unregister
);
448 EXPORT_SYMBOL_GPL(get_device
);
449 EXPORT_SYMBOL_GPL(put_device
);
451 EXPORT_SYMBOL_GPL(device_create_file
);
452 EXPORT_SYMBOL_GPL(device_remove_file
);