blob: be6b5bc0677d545c0f79efd659f98d268fffb200 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * drivers/base/core.c - core driver model code (device registration, etc)
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 *
7 * This file is released under the GPLv2
8 *
9 */
10
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#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>
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -070017#include <linux/kdev_t.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018
19#include <asm/semaphore.h>
20
21#include "base.h"
22#include "power/power.h"
23
24int (*platform_notify)(struct device * dev) = NULL;
25int (*platform_notify_remove)(struct device * dev) = NULL;
26
27/*
28 * sysfs bindings for devices.
29 */
30
Alan Stern3e956372006-06-16 17:10:48 -040031/**
32 * dev_driver_string - Return a device's driver name, if at all possible
33 * @dev: struct device to get the name of
34 *
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.
39 */
40const char *dev_driver_string(struct device *dev)
41{
42 return dev->driver ? dev->driver->name :
43 (dev->bus ? dev->bus->name : "");
44}
45EXPORT_SYMBOL_GPL(dev_driver_string);
46
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#define to_dev(obj) container_of(obj, struct device, kobj)
48#define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050static ssize_t
51dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
52{
53 struct device_attribute * dev_attr = to_dev_attr(attr);
54 struct device * dev = to_dev(kobj);
Dmitry Torokhov4a0c20b2005-04-29 01:23:47 -050055 ssize_t ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57 if (dev_attr->show)
Yani Ioannou54b6f352005-05-17 06:39:34 -040058 ret = dev_attr->show(dev, dev_attr, buf);
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 return ret;
60}
61
62static ssize_t
63dev_attr_store(struct kobject * kobj, struct attribute * attr,
64 const char * buf, size_t count)
65{
66 struct device_attribute * dev_attr = to_dev_attr(attr);
67 struct device * dev = to_dev(kobj);
Dmitry Torokhov4a0c20b2005-04-29 01:23:47 -050068 ssize_t ret = -EIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
70 if (dev_attr->store)
Yani Ioannou54b6f352005-05-17 06:39:34 -040071 ret = dev_attr->store(dev, dev_attr, buf, count);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 return ret;
73}
74
75static struct sysfs_ops dev_sysfs_ops = {
76 .show = dev_attr_show,
77 .store = dev_attr_store,
78};
79
80
81/**
82 * device_release - free device structure.
83 * @kobj: device's kobject.
84 *
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.
88 */
89static void device_release(struct kobject * kobj)
90{
91 struct device * dev = to_dev(kobj);
92
93 if (dev->release)
94 dev->release(dev);
95 else {
96 printk(KERN_ERR "Device '%s' does not have a release() function, "
97 "it is broken and must be fixed.\n",
98 dev->bus_id);
99 WARN_ON(1);
100 }
101}
102
103static struct kobj_type ktype_device = {
104 .release = device_release,
105 .sysfs_ops = &dev_sysfs_ops,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106};
107
108
Kay Sievers312c0042005-11-16 09:00:00 +0100109static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110{
111 struct kobj_type *ktype = get_ktype(kobj);
112
113 if (ktype == &ktype_device) {
114 struct device *dev = to_dev(kobj);
115 if (dev->bus)
116 return 1;
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700117 if (dev->class)
118 return 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 }
120 return 0;
121}
122
Kay Sievers312c0042005-11-16 09:00:00 +0100123static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
125 struct device *dev = to_dev(kobj);
126
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700127 if (dev->bus)
128 return dev->bus->name;
129 if (dev->class)
130 return dev->class->name;
131 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132}
133
Kay Sievers312c0042005-11-16 09:00:00 +0100134static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135 int num_envp, char *buffer, int buffer_size)
136{
137 struct device *dev = to_dev(kobj);
138 int i = 0;
139 int length = 0;
140 int retval = 0;
141
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700142 /* 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));
150 }
151
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 /* add bus name of physical device */
153 if (dev->bus)
Kay Sievers312c0042005-11-16 09:00:00 +0100154 add_uevent_var(envp, num_envp, &i,
155 buffer, buffer_size, &length,
156 "PHYSDEVBUS=%s", dev->bus->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
158 /* add driver name of physical device */
159 if (dev->driver)
Kay Sievers312c0042005-11-16 09:00:00 +0100160 add_uevent_var(envp, num_envp, &i,
161 buffer, buffer_size, &length,
162 "PHYSDEVDRIVER=%s", dev->driver->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
164 /* terminate, set to next free slot, shrink available space */
165 envp[i] = NULL;
166 envp = &envp[i];
167 num_envp -= i;
168 buffer = &buffer[length];
169 buffer_size -= length;
170
Kay Sievers312c0042005-11-16 09:00:00 +0100171 if (dev->bus && dev->bus->uevent) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 /* have the bus specific function add its stuff */
Kay Sievers312c0042005-11-16 09:00:00 +0100173 retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 if (retval) {
Kay Sievers312c0042005-11-16 09:00:00 +0100175 pr_debug ("%s - uevent() returned %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 __FUNCTION__, retval);
177 }
178 }
179
180 return retval;
181}
182
Kay Sievers312c0042005-11-16 09:00:00 +0100183static struct kset_uevent_ops device_uevent_ops = {
184 .filter = dev_uevent_filter,
185 .name = dev_uevent_name,
186 .uevent = dev_uevent,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187};
188
Kay Sieversa7fd6702005-10-01 14:49:43 +0200189static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
190 const char *buf, size_t count)
191{
Kay Sievers312c0042005-11-16 09:00:00 +0100192 kobject_uevent(&dev->kobj, KOBJ_ADD);
Kay Sieversa7fd6702005-10-01 14:49:43 +0200193 return count;
194}
195
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700196static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
197 char *buf)
198{
199 return print_dev_t(buf, dev->devt);
200}
201
Martin Waitz0863afb2006-01-09 20:53:55 -0800202/*
203 * devices_subsys - structure to be registered with kobject core.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 */
205
Kay Sievers312c0042005-11-16 09:00:00 +0100206decl_subsys(devices, &ktype_device, &device_uevent_ops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
208
209/**
210 * device_create_file - create sysfs attribute file for device.
211 * @dev: device.
212 * @attr: device attribute descriptor.
213 */
214
215int device_create_file(struct device * dev, struct device_attribute * attr)
216{
217 int error = 0;
218 if (get_device(dev)) {
219 error = sysfs_create_file(&dev->kobj, &attr->attr);
220 put_device(dev);
221 }
222 return error;
223}
224
225/**
226 * device_remove_file - remove sysfs attribute file.
227 * @dev: device.
228 * @attr: device attribute descriptor.
229 */
230
231void device_remove_file(struct device * dev, struct device_attribute * attr)
232{
233 if (get_device(dev)) {
234 sysfs_remove_file(&dev->kobj, &attr->attr);
235 put_device(dev);
236 }
237}
238
James Bottomley34bb61f2005-09-06 16:56:51 -0700239static void klist_children_get(struct klist_node *n)
240{
241 struct device *dev = container_of(n, struct device, knode_parent);
242
243 get_device(dev);
244}
245
246static void klist_children_put(struct klist_node *n)
247{
248 struct device *dev = container_of(n, struct device, knode_parent);
249
250 put_device(dev);
251}
252
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254/**
255 * device_initialize - init device structure.
256 * @dev: device.
257 *
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).
263 */
264
265void device_initialize(struct device *dev)
266{
267 kobj_set_kset_s(dev, devices_subsys);
268 kobject_init(&dev->kobj);
James Bottomley34bb61f2005-09-06 16:56:51 -0700269 klist_init(&dev->klist_children, klist_children_get,
270 klist_children_put);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271 INIT_LIST_HEAD(&dev->dma_pools);
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700272 INIT_LIST_HEAD(&dev->node);
mochel@digitalimplant.orgaf703162005-03-21 10:41:04 -0800273 init_MUTEX(&dev->sem);
David Brownell0ac85242005-09-12 19:39:34 -0700274 device_init_wakeup(dev, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275}
276
277/**
278 * device_add - add device to device hierarchy.
279 * @dev: device.
280 *
281 * This is part 2 of device_register(), though may be called
282 * separately _iff_ device_initialize() has been called separately.
283 *
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.
287 */
288int device_add(struct device *dev)
289{
290 struct device *parent = NULL;
Greg Kroah-Hartmane9a7d302006-06-20 13:59:20 -0700291 char *class_name = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 int error = -EINVAL;
293
294 dev = get_device(dev);
295 if (!dev || !strlen(dev->bus_id))
296 goto Error;
297
298 parent = get_device(dev->parent);
299
300 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
301
302 /* first, register with generic layer. */
303 kobject_set_name(&dev->kobj, "%s", dev->bus_id);
304 if (parent)
305 dev->kobj.parent = &parent->kobj;
306
307 if ((error = kobject_add(&dev->kobj)))
308 goto Error;
Kay Sieversa7fd6702005-10-01 14:49:43 +0200309
310 dev->uevent_attr.attr.name = "uevent";
311 dev->uevent_attr.attr.mode = S_IWUSR;
312 if (dev->driver)
313 dev->uevent_attr.attr.owner = dev->driver->owner;
314 dev->uevent_attr.store = store_uevent;
315 device_create_file(dev, &dev->uevent_attr);
316
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700317 if (MAJOR(dev->devt)) {
318 struct device_attribute *attr;
319 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
320 if (!attr) {
321 error = -ENOMEM;
322 goto PMError;
323 }
324 attr->attr.name = "dev";
325 attr->attr.mode = S_IRUGO;
326 if (dev->driver)
327 attr->attr.owner = dev->driver->owner;
328 attr->show = show_dev;
329 error = device_create_file(dev, attr);
330 if (error) {
331 kfree(attr);
332 goto attrError;
333 }
334
335 dev->devt_attr = attr;
336 }
337
Kay Sieversb9d9c822006-06-15 15:31:56 +0200338 if (dev->class) {
339 sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
340 "subsystem");
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700341 sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
342 dev->bus_id);
Greg Kroah-Hartmane9a7d302006-06-20 13:59:20 -0700343
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);
Kay Sieversb9d9c822006-06-15 15:31:56 +0200347 }
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700348
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 if ((error = device_pm_add(dev)))
350 goto PMError;
351 if ((error = bus_add_device(dev)))
352 goto BusError;
Kay Sievers53877d02006-04-04 20:42:26 +0200353 kobject_uevent(&dev->kobj, KOBJ_ADD);
354 bus_attach_device(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 if (parent)
James Bottomleyd856f1e32005-08-19 09:14:01 -0400356 klist_add_tail(&dev->knode_parent, &parent->klist_children);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357
Greg Kroah-Hartman5d9fd162006-06-22 17:17:32 -0700358 if (dev->class) {
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);
363 }
364
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 /* notify platform of device entry */
366 if (platform_notify)
367 platform_notify(dev);
368 Done:
Greg Kroah-Hartmane9a7d302006-06-20 13:59:20 -0700369 kfree(class_name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 put_device(dev);
371 return error;
372 BusError:
373 device_pm_remove(dev);
374 PMError:
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700375 if (dev->devt_attr) {
376 device_remove_file(dev, dev->devt_attr);
377 kfree(dev->devt_attr);
378 }
379 attrError:
Kay Sievers312c0042005-11-16 09:00:00 +0100380 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 kobject_del(&dev->kobj);
382 Error:
383 if (parent)
384 put_device(parent);
385 goto Done;
386}
387
388
389/**
390 * device_register - register a device with the system.
391 * @dev: pointer to the device structure
392 *
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.
399 */
400
401int device_register(struct device *dev)
402{
403 device_initialize(dev);
404 return device_add(dev);
405}
406
407
408/**
409 * get_device - increment reference count for device.
410 * @dev: device.
411 *
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
414 * pointer passed in.
415 */
416
417struct device * get_device(struct device * dev)
418{
419 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
420}
421
422
423/**
424 * put_device - decrement reference count.
425 * @dev: device in question.
426 */
427void put_device(struct device * dev)
428{
429 if (dev)
430 kobject_put(&dev->kobj);
431}
432
433
434/**
435 * device_del - delete device from system.
436 * @dev: device.
437 *
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.
443 *
444 * NOTE: this should be called manually _iff_ device_add() was
445 * also called manually.
446 */
447
448void device_del(struct device * dev)
449{
450 struct device * parent = dev->parent;
Greg Kroah-Hartmane9a7d302006-06-20 13:59:20 -0700451 char *class_name = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700452
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 if (parent)
Patrick Mocheld62c0f92005-06-24 08:39:33 -0700454 klist_del(&dev->knode_parent);
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700455 if (dev->devt_attr)
456 device_remove_file(dev, dev->devt_attr);
Kay Sieversb9d9c822006-06-15 15:31:56 +0200457 if (dev->class) {
458 sysfs_remove_link(&dev->kobj, "subsystem");
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700459 sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
Greg Kroah-Hartmane9a7d302006-06-20 13:59:20 -0700460 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);
463 kfree(class_name);
Greg Kroah-Hartman5d9fd162006-06-22 17:17:32 -0700464 down(&dev->class->sem);
465 list_del_init(&dev->node);
466 up(&dev->class->sem);
Kay Sieversb9d9c822006-06-15 15:31:56 +0200467 }
Kay Sieversa7fd6702005-10-01 14:49:43 +0200468 device_remove_file(dev, &dev->uevent_attr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469
470 /* Notify the platform of the removal, in case they
471 * need to do anything...
472 */
473 if (platform_notify_remove)
474 platform_notify_remove(dev);
475 bus_remove_device(dev);
476 device_pm_remove(dev);
Kay Sievers312c0042005-11-16 09:00:00 +0100477 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 kobject_del(&dev->kobj);
479 if (parent)
480 put_device(parent);
481}
482
483/**
484 * device_unregister - unregister device from system.
485 * @dev: device going away.
486 *
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.
493 */
494void device_unregister(struct device * dev)
495{
496 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
497 device_del(dev);
498 put_device(dev);
499}
500
501
mochel@digitalimplant.org36239572005-03-24 19:08:30 -0800502static struct device * next_device(struct klist_iter * i)
503{
504 struct klist_node * n = klist_next(i);
505 return n ? container_of(n, struct device, knode_parent) : NULL;
506}
507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508/**
509 * device_for_each_child - device child iterator.
Randy Dunlapc41455f2005-10-23 11:59:14 -0700510 * @parent: parent struct device.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 * @data: data for the callback.
512 * @fn: function to be called for each device.
513 *
Randy Dunlapc41455f2005-10-23 11:59:14 -0700514 * Iterate over @parent's child devices, and call @fn for each,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515 * passing it @data.
516 *
517 * We check the return of @fn each time. If it returns anything
518 * other than 0, we break out and return that value.
519 */
mochel@digitalimplant.org36239572005-03-24 19:08:30 -0800520int device_for_each_child(struct device * parent, void * data,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 int (*fn)(struct device *, void *))
522{
mochel@digitalimplant.org36239572005-03-24 19:08:30 -0800523 struct klist_iter i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 struct device * child;
525 int error = 0;
526
mochel@digitalimplant.org36239572005-03-24 19:08:30 -0800527 klist_iter_init(&parent->klist_children, &i);
528 while ((child = next_device(&i)) && !error)
529 error = fn(child, data);
530 klist_iter_exit(&i);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 return error;
532}
533
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534int __init devices_init(void)
535{
536 return subsystem_register(&devices_subsys);
537}
538
539EXPORT_SYMBOL_GPL(device_for_each_child);
540
541EXPORT_SYMBOL_GPL(device_initialize);
542EXPORT_SYMBOL_GPL(device_add);
543EXPORT_SYMBOL_GPL(device_register);
544
545EXPORT_SYMBOL_GPL(device_del);
546EXPORT_SYMBOL_GPL(device_unregister);
547EXPORT_SYMBOL_GPL(get_device);
548EXPORT_SYMBOL_GPL(put_device);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700549
550EXPORT_SYMBOL_GPL(device_create_file);
551EXPORT_SYMBOL_GPL(device_remove_file);
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700552
553
554static void device_create_release(struct device *dev)
555{
556 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
557 kfree(dev);
558}
559
560/**
561 * device_create - creates a device and registers it with sysfs
Henrik Kretzschmar42734da2006-07-05 00:53:19 +0200562 * @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
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700566 *
Henrik Kretzschmar42734da2006-07-05 00:53:19 +0200567 * This function can be used by char device classes. A struct device
568 * will be created in sysfs, registered to the specified class.
569 *
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700570 * A "dev" file will be created, showing the dev_t for the device, if
571 * the dev_t is not 0,0.
Henrik Kretzschmar42734da2006-07-05 00:53:19 +0200572 * 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
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700576 * pointer.
577 *
578 * Note: the struct class passed to this function must have previously
579 * been created with a call to class_create().
580 */
581struct device *device_create(struct class *class, struct device *parent,
582 dev_t devt, char *fmt, ...)
583{
584 va_list args;
585 struct device *dev = NULL;
586 int retval = -ENODEV;
587
588 if (class == NULL || IS_ERR(class))
589 goto error;
590 if (parent == NULL) {
591 printk(KERN_WARNING "%s does not work yet for NULL parents\n", __FUNCTION__);
592 goto error;
593 }
594
595 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
596 if (!dev) {
597 retval = -ENOMEM;
598 goto error;
599 }
600
601 dev->devt = devt;
602 dev->class = class;
603 dev->parent = parent;
604 dev->release = device_create_release;
605
606 va_start(args, fmt);
607 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
608 va_end(args);
609 retval = device_register(dev);
610 if (retval)
611 goto error;
612
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700613 return dev;
614
615error:
616 kfree(dev);
617 return ERR_PTR(retval);
618}
619EXPORT_SYMBOL_GPL(device_create);
620
621/**
622 * device_destroy - removes a device that was created with device_create()
Henrik Kretzschmar42734da2006-07-05 00:53:19 +0200623 * @class: pointer to the struct class that this device was registered with
624 * @devt: the dev_t of the device that was previously registered
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700625 *
Henrik Kretzschmar42734da2006-07-05 00:53:19 +0200626 * This call unregisters and cleans up a device that was created with a
627 * call to device_create().
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700628 */
629void device_destroy(struct class *class, dev_t devt)
630{
631 struct device *dev = NULL;
632 struct device *dev_tmp;
633
634 down(&class->sem);
635 list_for_each_entry(dev_tmp, &class->devices, node) {
636 if (dev_tmp->devt == devt) {
637 dev = dev_tmp;
638 break;
639 }
640 }
641 up(&class->sem);
642
Greg Kroah-Hartman5d9fd162006-06-22 17:17:32 -0700643 if (dev)
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700644 device_unregister(dev);
Greg Kroah-Hartman23681e42006-06-14 12:14:34 -0700645}
646EXPORT_SYMBOL_GPL(device_destroy);