Driver core: coding style cleanup
[linux-2.6/mini2440.git] / drivers / base / core.c
blobcff4fbfbb055285a365dfa2f840a264facfc3747
1 /*
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>
20 #include <linux/notifier.h>
22 #include <asm/semaphore.h>
24 #include "base.h"
25 #include "power/power.h"
27 int (*platform_notify)(struct device * dev) = NULL;
28 int (*platform_notify_remove)(struct device * dev) = NULL;
31 * sysfs bindings for devices.
34 /**
35 * dev_driver_string - Return a device's driver name, if at all possible
36 * @dev: struct device to get the name of
38 * Will return the device's driver's name if it is bound to a device. If
39 * the device is not bound to a device, it will return the name of the bus
40 * it is attached to. If it is not attached to a bus either, an empty
41 * string will be returned.
43 const char *dev_driver_string(struct device *dev)
45 return dev->driver ? dev->driver->name :
46 (dev->bus ? dev->bus->name :
47 (dev->class ? dev->class->name : ""));
49 EXPORT_SYMBOL(dev_driver_string);
51 #define to_dev(obj) container_of(obj, struct device, kobj)
52 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
54 static ssize_t
55 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
57 struct device_attribute * dev_attr = to_dev_attr(attr);
58 struct device * dev = to_dev(kobj);
59 ssize_t ret = -EIO;
61 if (dev_attr->show)
62 ret = dev_attr->show(dev, dev_attr, buf);
63 return ret;
66 static ssize_t
67 dev_attr_store(struct kobject * kobj, struct attribute * attr,
68 const char * buf, size_t count)
70 struct device_attribute * dev_attr = to_dev_attr(attr);
71 struct device * dev = to_dev(kobj);
72 ssize_t ret = -EIO;
74 if (dev_attr->store)
75 ret = dev_attr->store(dev, dev_attr, buf, count);
76 return ret;
79 static struct sysfs_ops dev_sysfs_ops = {
80 .show = dev_attr_show,
81 .store = dev_attr_store,
85 /**
86 * device_release - free device structure.
87 * @kobj: device's kobject.
89 * This is called once the reference count for the object
90 * reaches 0. We forward the call to the device's release
91 * method, which should handle actually freeing the structure.
93 static void device_release(struct kobject * kobj)
95 struct device * dev = to_dev(kobj);
97 if (dev->release)
98 dev->release(dev);
99 else if (dev->type && dev->type->release)
100 dev->type->release(dev);
101 else if (dev->class && dev->class->dev_release)
102 dev->class->dev_release(dev);
103 else {
104 printk(KERN_ERR "Device '%s' does not have a release() function, "
105 "it is broken and must be fixed.\n",
106 dev->bus_id);
107 WARN_ON(1);
111 static struct kobj_type ktype_device = {
112 .release = device_release,
113 .sysfs_ops = &dev_sysfs_ops,
117 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
119 struct kobj_type *ktype = get_ktype(kobj);
121 if (ktype == &ktype_device) {
122 struct device *dev = to_dev(kobj);
123 if (dev->uevent_suppress)
124 return 0;
125 if (dev->bus)
126 return 1;
127 if (dev->class)
128 return 1;
130 return 0;
133 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
135 struct device *dev = to_dev(kobj);
137 if (dev->bus)
138 return dev->bus->name;
139 if (dev->class)
140 return dev->class->name;
141 return NULL;
144 static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
145 int num_envp, char *buffer, int buffer_size)
147 struct device *dev = to_dev(kobj);
148 int i = 0;
149 int length = 0;
150 int retval = 0;
152 /* add the major/minor if present */
153 if (MAJOR(dev->devt)) {
154 add_uevent_var(envp, num_envp, &i,
155 buffer, buffer_size, &length,
156 "MAJOR=%u", MAJOR(dev->devt));
157 add_uevent_var(envp, num_envp, &i,
158 buffer, buffer_size, &length,
159 "MINOR=%u", MINOR(dev->devt));
162 if (dev->type && dev->type->name)
163 add_uevent_var(envp, num_envp, &i,
164 buffer, buffer_size, &length,
165 "DEVTYPE=%s", dev->type->name);
167 if (dev->driver)
168 add_uevent_var(envp, num_envp, &i,
169 buffer, buffer_size, &length,
170 "DRIVER=%s", dev->driver->name);
172 #ifdef CONFIG_SYSFS_DEPRECATED
173 if (dev->class) {
174 struct device *parent = dev->parent;
176 /* find first bus device in parent chain */
177 while (parent && !parent->bus)
178 parent = parent->parent;
179 if (parent && parent->bus) {
180 const char *path;
182 path = kobject_get_path(&parent->kobj, GFP_KERNEL);
183 if (path) {
184 add_uevent_var(envp, num_envp, &i,
185 buffer, buffer_size, &length,
186 "PHYSDEVPATH=%s", path);
187 kfree(path);
190 add_uevent_var(envp, num_envp, &i,
191 buffer, buffer_size, &length,
192 "PHYSDEVBUS=%s", parent->bus->name);
194 if (parent->driver)
195 add_uevent_var(envp, num_envp, &i,
196 buffer, buffer_size, &length,
197 "PHYSDEVDRIVER=%s", parent->driver->name);
199 } else if (dev->bus) {
200 add_uevent_var(envp, num_envp, &i,
201 buffer, buffer_size, &length,
202 "PHYSDEVBUS=%s", dev->bus->name);
204 if (dev->driver)
205 add_uevent_var(envp, num_envp, &i,
206 buffer, buffer_size, &length,
207 "PHYSDEVDRIVER=%s", dev->driver->name);
209 #endif
211 /* terminate, set to next free slot, shrink available space */
212 envp[i] = NULL;
213 envp = &envp[i];
214 num_envp -= i;
215 buffer = &buffer[length];
216 buffer_size -= length;
218 if (dev->bus && dev->bus->uevent) {
219 /* have the bus specific function add its stuff */
220 retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
221 if (retval)
222 pr_debug ("%s: bus uevent() returned %d\n",
223 __FUNCTION__, retval);
226 if (dev->class && dev->class->dev_uevent) {
227 /* have the class specific function add its stuff */
228 retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size);
229 if (retval)
230 pr_debug("%s: class uevent() returned %d\n",
231 __FUNCTION__, retval);
234 if (dev->type && dev->type->uevent) {
235 /* have the device type specific fuction add its stuff */
236 retval = dev->type->uevent(dev, envp, num_envp, buffer, buffer_size);
237 if (retval)
238 pr_debug("%s: dev_type uevent() returned %d\n",
239 __FUNCTION__, retval);
242 return retval;
245 static struct kset_uevent_ops device_uevent_ops = {
246 .filter = dev_uevent_filter,
247 .name = dev_uevent_name,
248 .uevent = dev_uevent,
251 static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
252 char *buf)
254 struct kobject *top_kobj;
255 struct kset *kset;
256 char *envp[32];
257 char *data = NULL;
258 char *pos;
259 int i;
260 size_t count = 0;
261 int retval;
263 /* search the kset, the device belongs to */
264 top_kobj = &dev->kobj;
265 if (!top_kobj->kset && top_kobj->parent) {
266 do {
267 top_kobj = top_kobj->parent;
268 } while (!top_kobj->kset && top_kobj->parent);
270 if (!top_kobj->kset)
271 goto out;
272 kset = top_kobj->kset;
273 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
274 goto out;
276 /* respect filter */
277 if (kset->uevent_ops && kset->uevent_ops->filter)
278 if (!kset->uevent_ops->filter(kset, &dev->kobj))
279 goto out;
281 data = (char *)get_zeroed_page(GFP_KERNEL);
282 if (!data)
283 return -ENOMEM;
285 /* let the kset specific function add its keys */
286 pos = data;
287 retval = kset->uevent_ops->uevent(kset, &dev->kobj,
288 envp, ARRAY_SIZE(envp),
289 pos, PAGE_SIZE);
290 if (retval)
291 goto out;
293 /* copy keys to file */
294 for (i = 0; envp[i]; i++) {
295 pos = &buf[count];
296 count += sprintf(pos, "%s\n", envp[i]);
298 out:
299 free_page((unsigned long)data);
300 return count;
303 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
304 const char *buf, size_t count)
306 if (memcmp(buf, "add", 3) != 0)
307 dev_err(dev, "uevent: unsupported action-string; this will "
308 "be ignored in a future kernel version");
309 kobject_uevent(&dev->kobj, KOBJ_ADD);
310 return count;
313 static int device_add_attributes(struct device *dev,
314 struct device_attribute *attrs)
316 int error = 0;
317 int i;
319 if (attrs) {
320 for (i = 0; attr_name(attrs[i]); i++) {
321 error = device_create_file(dev, &attrs[i]);
322 if (error)
323 break;
325 if (error)
326 while (--i >= 0)
327 device_remove_file(dev, &attrs[i]);
329 return error;
332 static void device_remove_attributes(struct device *dev,
333 struct device_attribute *attrs)
335 int i;
337 if (attrs)
338 for (i = 0; attr_name(attrs[i]); i++)
339 device_remove_file(dev, &attrs[i]);
342 static int device_add_groups(struct device *dev,
343 struct attribute_group **groups)
345 int error = 0;
346 int i;
348 if (groups) {
349 for (i = 0; groups[i]; i++) {
350 error = sysfs_create_group(&dev->kobj, groups[i]);
351 if (error) {
352 while (--i >= 0)
353 sysfs_remove_group(&dev->kobj, groups[i]);
354 break;
358 return error;
361 static void device_remove_groups(struct device *dev,
362 struct attribute_group **groups)
364 int i;
366 if (groups)
367 for (i = 0; groups[i]; i++)
368 sysfs_remove_group(&dev->kobj, groups[i]);
371 static int device_add_attrs(struct device *dev)
373 struct class *class = dev->class;
374 struct device_type *type = dev->type;
375 int error;
377 if (class) {
378 error = device_add_attributes(dev, class->dev_attrs);
379 if (error)
380 return error;
383 if (type) {
384 error = device_add_groups(dev, type->groups);
385 if (error)
386 goto err_remove_class_attrs;
389 error = device_add_groups(dev, dev->groups);
390 if (error)
391 goto err_remove_type_groups;
393 return 0;
395 err_remove_type_groups:
396 if (type)
397 device_remove_groups(dev, type->groups);
398 err_remove_class_attrs:
399 if (class)
400 device_remove_attributes(dev, class->dev_attrs);
402 return error;
405 static void device_remove_attrs(struct device *dev)
407 struct class *class = dev->class;
408 struct device_type *type = dev->type;
410 device_remove_groups(dev, dev->groups);
412 if (type)
413 device_remove_groups(dev, type->groups);
415 if (class)
416 device_remove_attributes(dev, class->dev_attrs);
420 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
421 char *buf)
423 return print_dev_t(buf, dev->devt);
427 * devices_subsys - structure to be registered with kobject core.
430 decl_subsys(devices, &ktype_device, &device_uevent_ops);
434 * device_create_file - create sysfs attribute file for device.
435 * @dev: device.
436 * @attr: device attribute descriptor.
439 int device_create_file(struct device * dev, struct device_attribute * attr)
441 int error = 0;
442 if (get_device(dev)) {
443 error = sysfs_create_file(&dev->kobj, &attr->attr);
444 put_device(dev);
446 return error;
450 * device_remove_file - remove sysfs attribute file.
451 * @dev: device.
452 * @attr: device attribute descriptor.
455 void device_remove_file(struct device * dev, struct device_attribute * attr)
457 if (get_device(dev)) {
458 sysfs_remove_file(&dev->kobj, &attr->attr);
459 put_device(dev);
464 * device_create_bin_file - create sysfs binary attribute file for device.
465 * @dev: device.
466 * @attr: device binary attribute descriptor.
468 int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
470 int error = -EINVAL;
471 if (dev)
472 error = sysfs_create_bin_file(&dev->kobj, attr);
473 return error;
475 EXPORT_SYMBOL_GPL(device_create_bin_file);
478 * device_remove_bin_file - remove sysfs binary attribute file
479 * @dev: device.
480 * @attr: device binary attribute descriptor.
482 void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
484 if (dev)
485 sysfs_remove_bin_file(&dev->kobj, attr);
487 EXPORT_SYMBOL_GPL(device_remove_bin_file);
490 * device_schedule_callback_owner - helper to schedule a callback for a device
491 * @dev: device.
492 * @func: callback function to invoke later.
493 * @owner: module owning the callback routine
495 * Attribute methods must not unregister themselves or their parent device
496 * (which would amount to the same thing). Attempts to do so will deadlock,
497 * since unregistration is mutually exclusive with driver callbacks.
499 * Instead methods can call this routine, which will attempt to allocate
500 * and schedule a workqueue request to call back @func with @dev as its
501 * argument in the workqueue's process context. @dev will be pinned until
502 * @func returns.
504 * This routine is usually called via the inline device_schedule_callback(),
505 * which automatically sets @owner to THIS_MODULE.
507 * Returns 0 if the request was submitted, -ENOMEM if storage could not
508 * be allocated, -ENODEV if a reference to @owner isn't available.
510 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
511 * underlying sysfs routine (since it is intended for use by attribute
512 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
514 int device_schedule_callback_owner(struct device *dev,
515 void (*func)(struct device *), struct module *owner)
517 return sysfs_schedule_callback(&dev->kobj,
518 (void (*)(void *)) func, dev, owner);
520 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
522 static void klist_children_get(struct klist_node *n)
524 struct device *dev = container_of(n, struct device, knode_parent);
526 get_device(dev);
529 static void klist_children_put(struct klist_node *n)
531 struct device *dev = container_of(n, struct device, knode_parent);
533 put_device(dev);
538 * device_initialize - init device structure.
539 * @dev: device.
541 * This prepares the device for use by other layers,
542 * including adding it to the device hierarchy.
543 * It is the first half of device_register(), if called by
544 * that, though it can also be called separately, so one
545 * may use @dev's fields (e.g. the refcount).
548 void device_initialize(struct device *dev)
550 kobj_set_kset_s(dev, devices_subsys);
551 kobject_init(&dev->kobj);
552 klist_init(&dev->klist_children, klist_children_get,
553 klist_children_put);
554 INIT_LIST_HEAD(&dev->dma_pools);
555 INIT_LIST_HEAD(&dev->node);
556 init_MUTEX(&dev->sem);
557 spin_lock_init(&dev->devres_lock);
558 INIT_LIST_HEAD(&dev->devres_head);
559 device_init_wakeup(dev, 0);
560 set_dev_node(dev, -1);
563 #ifdef CONFIG_SYSFS_DEPRECATED
564 static struct kobject * get_device_parent(struct device *dev,
565 struct device *parent)
567 /* Set the parent to the class, not the parent device */
568 /* this keeps sysfs from having a symlink to make old udevs happy */
569 if (dev->class)
570 return &dev->class->subsys.kobj;
571 else if (parent)
572 return &parent->kobj;
574 return NULL;
576 #else
577 static struct kobject *virtual_device_parent(struct device *dev)
579 static struct kobject *virtual_dir = NULL;
581 if (!virtual_dir)
582 virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual");
584 return virtual_dir;
587 static struct kobject * get_device_parent(struct device *dev,
588 struct device *parent)
590 if (dev->class) {
591 struct kobject *kobj = NULL;
592 struct kobject *parent_kobj;
593 struct kobject *k;
596 * If we have no parent, we live in "virtual".
597 * Class-devices with a bus-device as parent, live
598 * in a class-directory to prevent namespace collisions.
600 if (parent == NULL)
601 parent_kobj = virtual_device_parent(dev);
602 else if (parent->class)
603 return &parent->kobj;
604 else
605 parent_kobj = &parent->kobj;
607 /* find our class-directory at the parent and reference it */
608 spin_lock(&dev->class->class_dirs.list_lock);
609 list_for_each_entry(k, &dev->class->class_dirs.list, entry)
610 if (k->parent == parent_kobj) {
611 kobj = kobject_get(k);
612 break;
614 spin_unlock(&dev->class->class_dirs.list_lock);
615 if (kobj)
616 return kobj;
618 /* or create a new class-directory at the parent device */
619 return kobject_kset_add_dir(&dev->class->class_dirs,
620 parent_kobj, dev->class->name);
623 if (parent)
624 return &parent->kobj;
625 return NULL;
627 #endif
629 static int setup_parent(struct device *dev, struct device *parent)
631 struct kobject *kobj;
632 kobj = get_device_parent(dev, parent);
633 if (IS_ERR(kobj))
634 return PTR_ERR(kobj);
635 if (kobj)
636 dev->kobj.parent = kobj;
637 return 0;
641 * device_add - add device to device hierarchy.
642 * @dev: device.
644 * This is part 2 of device_register(), though may be called
645 * separately _iff_ device_initialize() has been called separately.
647 * This adds it to the kobject hierarchy via kobject_add(), adds it
648 * to the global and sibling lists for the device, then
649 * adds it to the other relevant subsystems of the driver model.
651 int device_add(struct device *dev)
653 struct device *parent = NULL;
654 char *class_name = NULL;
655 struct class_interface *class_intf;
656 int error = -EINVAL;
658 dev = get_device(dev);
659 if (!dev || !strlen(dev->bus_id))
660 goto Error;
662 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
664 parent = get_device(dev->parent);
665 error = setup_parent(dev, parent);
666 if (error)
667 goto Error;
669 /* first, register with generic layer. */
670 kobject_set_name(&dev->kobj, "%s", dev->bus_id);
671 error = kobject_add(&dev->kobj);
672 if (error)
673 goto Error;
675 /* notify platform of device entry */
676 if (platform_notify)
677 platform_notify(dev);
679 /* notify clients of device entry (new way) */
680 if (dev->bus)
681 blocking_notifier_call_chain(&dev->bus->bus_notifier,
682 BUS_NOTIFY_ADD_DEVICE, dev);
684 dev->uevent_attr.attr.name = "uevent";
685 dev->uevent_attr.attr.mode = S_IRUGO | S_IWUSR;
686 if (dev->driver)
687 dev->uevent_attr.attr.owner = dev->driver->owner;
688 dev->uevent_attr.store = store_uevent;
689 dev->uevent_attr.show = show_uevent;
690 error = device_create_file(dev, &dev->uevent_attr);
691 if (error)
692 goto attrError;
694 if (MAJOR(dev->devt)) {
695 struct device_attribute *attr;
696 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
697 if (!attr) {
698 error = -ENOMEM;
699 goto ueventattrError;
701 attr->attr.name = "dev";
702 attr->attr.mode = S_IRUGO;
703 if (dev->driver)
704 attr->attr.owner = dev->driver->owner;
705 attr->show = show_dev;
706 error = device_create_file(dev, attr);
707 if (error) {
708 kfree(attr);
709 goto ueventattrError;
712 dev->devt_attr = attr;
715 if (dev->class) {
716 sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
717 "subsystem");
718 /* If this is not a "fake" compatible device, then create the
719 * symlink from the class to the device. */
720 if (dev->kobj.parent != &dev->class->subsys.kobj)
721 sysfs_create_link(&dev->class->subsys.kobj,
722 &dev->kobj, dev->bus_id);
723 if (parent) {
724 sysfs_create_link(&dev->kobj, &dev->parent->kobj,
725 "device");
726 #ifdef CONFIG_SYSFS_DEPRECATED
727 class_name = make_class_name(dev->class->name,
728 &dev->kobj);
729 if (class_name)
730 sysfs_create_link(&dev->parent->kobj,
731 &dev->kobj, class_name);
732 #endif
736 error = device_add_attrs(dev);
737 if (error)
738 goto AttrsError;
739 error = device_pm_add(dev);
740 if (error)
741 goto PMError;
742 error = bus_add_device(dev);
743 if (error)
744 goto BusError;
745 kobject_uevent(&dev->kobj, KOBJ_ADD);
746 bus_attach_device(dev);
747 if (parent)
748 klist_add_tail(&dev->knode_parent, &parent->klist_children);
750 if (dev->class) {
751 down(&dev->class->sem);
752 /* tie the class to the device */
753 list_add_tail(&dev->node, &dev->class->devices);
755 /* notify any interfaces that the device is here */
756 list_for_each_entry(class_intf, &dev->class->interfaces, node)
757 if (class_intf->add_dev)
758 class_intf->add_dev(dev, class_intf);
759 up(&dev->class->sem);
761 Done:
762 kfree(class_name);
763 put_device(dev);
764 return error;
765 BusError:
766 device_pm_remove(dev);
767 PMError:
768 if (dev->bus)
769 blocking_notifier_call_chain(&dev->bus->bus_notifier,
770 BUS_NOTIFY_DEL_DEVICE, dev);
771 device_remove_attrs(dev);
772 AttrsError:
773 if (dev->devt_attr) {
774 device_remove_file(dev, dev->devt_attr);
775 kfree(dev->devt_attr);
778 if (dev->class) {
779 sysfs_remove_link(&dev->kobj, "subsystem");
780 /* If this is not a "fake" compatible device, remove the
781 * symlink from the class to the device. */
782 if (dev->kobj.parent != &dev->class->subsys.kobj)
783 sysfs_remove_link(&dev->class->subsys.kobj,
784 dev->bus_id);
785 if (parent) {
786 #ifdef CONFIG_SYSFS_DEPRECATED
787 char *class_name = make_class_name(dev->class->name,
788 &dev->kobj);
789 if (class_name)
790 sysfs_remove_link(&dev->parent->kobj,
791 class_name);
792 kfree(class_name);
793 #endif
794 sysfs_remove_link(&dev->kobj, "device");
797 ueventattrError:
798 device_remove_file(dev, &dev->uevent_attr);
799 attrError:
800 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
801 kobject_del(&dev->kobj);
802 Error:
803 if (parent)
804 put_device(parent);
805 goto Done;
810 * device_register - register a device with the system.
811 * @dev: pointer to the device structure
813 * This happens in two clean steps - initialize the device
814 * and add it to the system. The two steps can be called
815 * separately, but this is the easiest and most common.
816 * I.e. you should only call the two helpers separately if
817 * have a clearly defined need to use and refcount the device
818 * before it is added to the hierarchy.
821 int device_register(struct device *dev)
823 device_initialize(dev);
824 return device_add(dev);
829 * get_device - increment reference count for device.
830 * @dev: device.
832 * This simply forwards the call to kobject_get(), though
833 * we do take care to provide for the case that we get a NULL
834 * pointer passed in.
837 struct device * get_device(struct device * dev)
839 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
844 * put_device - decrement reference count.
845 * @dev: device in question.
847 void put_device(struct device * dev)
849 if (dev)
850 kobject_put(&dev->kobj);
855 * device_del - delete device from system.
856 * @dev: device.
858 * This is the first part of the device unregistration
859 * sequence. This removes the device from the lists we control
860 * from here, has it removed from the other driver model
861 * subsystems it was added to in device_add(), and removes it
862 * from the kobject hierarchy.
864 * NOTE: this should be called manually _iff_ device_add() was
865 * also called manually.
868 void device_del(struct device * dev)
870 struct device * parent = dev->parent;
871 struct class_interface *class_intf;
873 if (parent)
874 klist_del(&dev->knode_parent);
875 if (dev->devt_attr) {
876 device_remove_file(dev, dev->devt_attr);
877 kfree(dev->devt_attr);
879 if (dev->class) {
880 sysfs_remove_link(&dev->kobj, "subsystem");
881 /* If this is not a "fake" compatible device, remove the
882 * symlink from the class to the device. */
883 if (dev->kobj.parent != &dev->class->subsys.kobj)
884 sysfs_remove_link(&dev->class->subsys.kobj,
885 dev->bus_id);
886 if (parent) {
887 #ifdef CONFIG_SYSFS_DEPRECATED
888 char *class_name = make_class_name(dev->class->name,
889 &dev->kobj);
890 if (class_name)
891 sysfs_remove_link(&dev->parent->kobj,
892 class_name);
893 kfree(class_name);
894 #endif
895 sysfs_remove_link(&dev->kobj, "device");
898 down(&dev->class->sem);
899 /* notify any interfaces that the device is now gone */
900 list_for_each_entry(class_intf, &dev->class->interfaces, node)
901 if (class_intf->remove_dev)
902 class_intf->remove_dev(dev, class_intf);
903 /* remove the device from the class list */
904 list_del_init(&dev->node);
905 up(&dev->class->sem);
907 /* If we live in a parent class-directory, unreference it */
908 if (dev->kobj.parent->kset == &dev->class->class_dirs) {
909 struct device *d;
910 int other = 0;
913 * if we are the last child of our class, delete
914 * our class-directory at this parent
916 down(&dev->class->sem);
917 list_for_each_entry(d, &dev->class->devices, node) {
918 if (d == dev)
919 continue;
920 if (d->kobj.parent == dev->kobj.parent) {
921 other = 1;
922 break;
925 if (!other)
926 kobject_del(dev->kobj.parent);
928 kobject_put(dev->kobj.parent);
929 up(&dev->class->sem);
932 device_remove_file(dev, &dev->uevent_attr);
933 device_remove_attrs(dev);
934 bus_remove_device(dev);
937 * Some platform devices are driven without driver attached
938 * and managed resources may have been acquired. Make sure
939 * all resources are released.
941 devres_release_all(dev);
943 /* Notify the platform of the removal, in case they
944 * need to do anything...
946 if (platform_notify_remove)
947 platform_notify_remove(dev);
948 if (dev->bus)
949 blocking_notifier_call_chain(&dev->bus->bus_notifier,
950 BUS_NOTIFY_DEL_DEVICE, dev);
951 device_pm_remove(dev);
952 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
953 kobject_del(&dev->kobj);
954 if (parent)
955 put_device(parent);
959 * device_unregister - unregister device from system.
960 * @dev: device going away.
962 * We do this in two parts, like we do device_register(). First,
963 * we remove it from all the subsystems with device_del(), then
964 * we decrement the reference count via put_device(). If that
965 * is the final reference count, the device will be cleaned up
966 * via device_release() above. Otherwise, the structure will
967 * stick around until the final reference to the device is dropped.
969 void device_unregister(struct device * dev)
971 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
972 device_del(dev);
973 put_device(dev);
977 static struct device * next_device(struct klist_iter * i)
979 struct klist_node * n = klist_next(i);
980 return n ? container_of(n, struct device, knode_parent) : NULL;
984 * device_for_each_child - device child iterator.
985 * @parent: parent struct device.
986 * @data: data for the callback.
987 * @fn: function to be called for each device.
989 * Iterate over @parent's child devices, and call @fn for each,
990 * passing it @data.
992 * We check the return of @fn each time. If it returns anything
993 * other than 0, we break out and return that value.
995 int device_for_each_child(struct device * parent, void * data,
996 int (*fn)(struct device *, void *))
998 struct klist_iter i;
999 struct device * child;
1000 int error = 0;
1002 klist_iter_init(&parent->klist_children, &i);
1003 while ((child = next_device(&i)) && !error)
1004 error = fn(child, data);
1005 klist_iter_exit(&i);
1006 return error;
1010 * device_find_child - device iterator for locating a particular device.
1011 * @parent: parent struct device
1012 * @data: Data to pass to match function
1013 * @match: Callback function to check device
1015 * This is similar to the device_for_each_child() function above, but it
1016 * returns a reference to a device that is 'found' for later use, as
1017 * determined by the @match callback.
1019 * The callback should return 0 if the device doesn't match and non-zero
1020 * if it does. If the callback returns non-zero and a reference to the
1021 * current device can be obtained, this function will return to the caller
1022 * and not iterate over any more devices.
1024 struct device * device_find_child(struct device *parent, void *data,
1025 int (*match)(struct device *, void *))
1027 struct klist_iter i;
1028 struct device *child;
1030 if (!parent)
1031 return NULL;
1033 klist_iter_init(&parent->klist_children, &i);
1034 while ((child = next_device(&i)))
1035 if (match(child, data) && get_device(child))
1036 break;
1037 klist_iter_exit(&i);
1038 return child;
1041 int __init devices_init(void)
1043 return subsystem_register(&devices_subsys);
1046 EXPORT_SYMBOL_GPL(device_for_each_child);
1047 EXPORT_SYMBOL_GPL(device_find_child);
1049 EXPORT_SYMBOL_GPL(device_initialize);
1050 EXPORT_SYMBOL_GPL(device_add);
1051 EXPORT_SYMBOL_GPL(device_register);
1053 EXPORT_SYMBOL_GPL(device_del);
1054 EXPORT_SYMBOL_GPL(device_unregister);
1055 EXPORT_SYMBOL_GPL(get_device);
1056 EXPORT_SYMBOL_GPL(put_device);
1058 EXPORT_SYMBOL_GPL(device_create_file);
1059 EXPORT_SYMBOL_GPL(device_remove_file);
1062 static void device_create_release(struct device *dev)
1064 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
1065 kfree(dev);
1069 * device_create - creates a device and registers it with sysfs
1070 * @class: pointer to the struct class that this device should be registered to
1071 * @parent: pointer to the parent struct device of this new device, if any
1072 * @devt: the dev_t for the char device to be added
1073 * @fmt: string for the device's name
1075 * This function can be used by char device classes. A struct device
1076 * will be created in sysfs, registered to the specified class.
1078 * A "dev" file will be created, showing the dev_t for the device, if
1079 * the dev_t is not 0,0.
1080 * If a pointer to a parent struct device is passed in, the newly created
1081 * struct device will be a child of that device in sysfs.
1082 * The pointer to the struct device will be returned from the call.
1083 * Any further sysfs files that might be required can be created using this
1084 * pointer.
1086 * Note: the struct class passed to this function must have previously
1087 * been created with a call to class_create().
1089 struct device *device_create(struct class *class, struct device *parent,
1090 dev_t devt, const char *fmt, ...)
1092 va_list args;
1093 struct device *dev = NULL;
1094 int retval = -ENODEV;
1096 if (class == NULL || IS_ERR(class))
1097 goto error;
1099 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1100 if (!dev) {
1101 retval = -ENOMEM;
1102 goto error;
1105 dev->devt = devt;
1106 dev->class = class;
1107 dev->parent = parent;
1108 dev->release = device_create_release;
1110 va_start(args, fmt);
1111 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
1112 va_end(args);
1113 retval = device_register(dev);
1114 if (retval)
1115 goto error;
1117 return dev;
1119 error:
1120 kfree(dev);
1121 return ERR_PTR(retval);
1123 EXPORT_SYMBOL_GPL(device_create);
1126 * device_destroy - removes a device that was created with device_create()
1127 * @class: pointer to the struct class that this device was registered with
1128 * @devt: the dev_t of the device that was previously registered
1130 * This call unregisters and cleans up a device that was created with a
1131 * call to device_create().
1133 void device_destroy(struct class *class, dev_t devt)
1135 struct device *dev = NULL;
1136 struct device *dev_tmp;
1138 down(&class->sem);
1139 list_for_each_entry(dev_tmp, &class->devices, node) {
1140 if (dev_tmp->devt == devt) {
1141 dev = dev_tmp;
1142 break;
1145 up(&class->sem);
1147 if (dev)
1148 device_unregister(dev);
1150 EXPORT_SYMBOL_GPL(device_destroy);
1153 * device_rename - renames a device
1154 * @dev: the pointer to the struct device to be renamed
1155 * @new_name: the new name of the device
1157 int device_rename(struct device *dev, char *new_name)
1159 char *old_class_name = NULL;
1160 char *new_class_name = NULL;
1161 char *old_symlink_name = NULL;
1162 int error;
1164 dev = get_device(dev);
1165 if (!dev)
1166 return -EINVAL;
1168 pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name);
1170 #ifdef CONFIG_SYSFS_DEPRECATED
1171 if ((dev->class) && (dev->parent))
1172 old_class_name = make_class_name(dev->class->name, &dev->kobj);
1173 #endif
1175 if (dev->class) {
1176 old_symlink_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
1177 if (!old_symlink_name) {
1178 error = -ENOMEM;
1179 goto out_free_old_class;
1181 strlcpy(old_symlink_name, dev->bus_id, BUS_ID_SIZE);
1184 strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
1186 error = kobject_rename(&dev->kobj, new_name);
1188 #ifdef CONFIG_SYSFS_DEPRECATED
1189 if (old_class_name) {
1190 new_class_name = make_class_name(dev->class->name, &dev->kobj);
1191 if (new_class_name) {
1192 sysfs_create_link(&dev->parent->kobj, &dev->kobj,
1193 new_class_name);
1194 sysfs_remove_link(&dev->parent->kobj, old_class_name);
1197 #endif
1199 if (dev->class) {
1200 sysfs_remove_link(&dev->class->subsys.kobj,
1201 old_symlink_name);
1202 sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
1203 dev->bus_id);
1205 put_device(dev);
1207 kfree(new_class_name);
1208 kfree(old_symlink_name);
1209 out_free_old_class:
1210 kfree(old_class_name);
1212 return error;
1214 EXPORT_SYMBOL_GPL(device_rename);
1216 static int device_move_class_links(struct device *dev,
1217 struct device *old_parent,
1218 struct device *new_parent)
1220 int error = 0;
1221 #ifdef CONFIG_SYSFS_DEPRECATED
1222 char *class_name;
1224 class_name = make_class_name(dev->class->name, &dev->kobj);
1225 if (!class_name) {
1226 error = -ENOMEM;
1227 goto out;
1229 if (old_parent) {
1230 sysfs_remove_link(&dev->kobj, "device");
1231 sysfs_remove_link(&old_parent->kobj, class_name);
1233 if (new_parent) {
1234 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1235 "device");
1236 if (error)
1237 goto out;
1238 error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
1239 class_name);
1240 if (error)
1241 sysfs_remove_link(&dev->kobj, "device");
1243 else
1244 error = 0;
1245 out:
1246 kfree(class_name);
1247 return error;
1248 #else
1249 if (old_parent)
1250 sysfs_remove_link(&dev->kobj, "device");
1251 if (new_parent)
1252 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1253 "device");
1254 return error;
1255 #endif
1259 * device_move - moves a device to a new parent
1260 * @dev: the pointer to the struct device to be moved
1261 * @new_parent: the new parent of the device (can by NULL)
1263 int device_move(struct device *dev, struct device *new_parent)
1265 int error;
1266 struct device *old_parent;
1267 struct kobject *new_parent_kobj;
1269 dev = get_device(dev);
1270 if (!dev)
1271 return -EINVAL;
1273 new_parent = get_device(new_parent);
1274 new_parent_kobj = get_device_parent (dev, new_parent);
1275 if (IS_ERR(new_parent_kobj)) {
1276 error = PTR_ERR(new_parent_kobj);
1277 put_device(new_parent);
1278 goto out;
1280 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
1281 new_parent ? new_parent->bus_id : "<NULL>");
1282 error = kobject_move(&dev->kobj, new_parent_kobj);
1283 if (error) {
1284 put_device(new_parent);
1285 goto out;
1287 old_parent = dev->parent;
1288 dev->parent = new_parent;
1289 if (old_parent)
1290 klist_remove(&dev->knode_parent);
1291 if (new_parent)
1292 klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1293 if (!dev->class)
1294 goto out_put;
1295 error = device_move_class_links(dev, old_parent, new_parent);
1296 if (error) {
1297 /* We ignore errors on cleanup since we're hosed anyway... */
1298 device_move_class_links(dev, new_parent, old_parent);
1299 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1300 if (new_parent)
1301 klist_remove(&dev->knode_parent);
1302 if (old_parent)
1303 klist_add_tail(&dev->knode_parent,
1304 &old_parent->klist_children);
1306 put_device(new_parent);
1307 goto out;
1309 out_put:
1310 put_device(old_parent);
1311 out:
1312 put_device(dev);
1313 return error;
1316 EXPORT_SYMBOL_GPL(device_move);