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>
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.
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)
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);
62 ret = dev_attr->show(dev, dev_attr, buf);
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);
75 ret = dev_attr->store(dev, dev_attr, buf, count);
79 static struct sysfs_ops dev_sysfs_ops = {
80 .show = dev_attr_show,
81 .store = dev_attr_store,
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);
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);
104 printk(KERN_ERR "Device '%s' does not have a release() function, "
105 "it is broken and must be fixed.\n",
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)
133 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
135 struct device *dev = to_dev(kobj);
138 return dev->bus->name;
140 return dev->class->name;
144 static int dev_uevent(struct kset *kset, struct kobject *kobj,
145 struct kobj_uevent_env *env)
147 struct device *dev = to_dev(kobj);
150 /* add the major/minor if present */
151 if (MAJOR(dev->devt)) {
152 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
153 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
156 if (dev->type && dev->type->name)
157 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
160 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
162 #ifdef CONFIG_SYSFS_DEPRECATED
164 struct device *parent = dev->parent;
166 /* find first bus device in parent chain */
167 while (parent && !parent->bus)
168 parent = parent->parent;
169 if (parent && parent->bus) {
172 path = kobject_get_path(&parent->kobj, GFP_KERNEL);
174 add_uevent_var(env, "PHYSDEVPATH=%s", path);
178 add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name);
181 add_uevent_var(env, "PHYSDEVDRIVER=%s",
182 parent->driver->name);
184 } else if (dev->bus) {
185 add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
188 add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
192 /* have the bus specific function add its stuff */
193 if (dev->bus && dev->bus->uevent) {
194 retval = dev->bus->uevent(dev, env);
196 pr_debug ("%s: bus uevent() returned %d\n",
197 __FUNCTION__, retval);
200 /* have the class specific function add its stuff */
201 if (dev->class && dev->class->dev_uevent) {
202 retval = dev->class->dev_uevent(dev, env);
204 pr_debug("%s: class uevent() returned %d\n",
205 __FUNCTION__, retval);
208 /* have the device type specific fuction add its stuff */
209 if (dev->type && dev->type->uevent) {
210 retval = dev->type->uevent(dev, env);
212 pr_debug("%s: dev_type uevent() returned %d\n",
213 __FUNCTION__, retval);
219 static struct kset_uevent_ops device_uevent_ops = {
220 .filter = dev_uevent_filter,
221 .name = dev_uevent_name,
222 .uevent = dev_uevent,
225 static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
228 struct kobject *top_kobj;
230 struct kobj_uevent_env *env = NULL;
235 /* search the kset, the device belongs to */
236 top_kobj = &dev->kobj;
237 if (!top_kobj->kset && top_kobj->parent) {
239 top_kobj = top_kobj->parent;
240 } while (!top_kobj->kset && top_kobj->parent);
244 kset = top_kobj->kset;
245 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
249 if (kset->uevent_ops && kset->uevent_ops->filter)
250 if (!kset->uevent_ops->filter(kset, &dev->kobj))
253 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
257 /* let the kset specific function add its keys */
258 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
262 /* copy keys to file */
263 for (i = 0; i < env->envp_idx; i++)
264 count += sprintf(&buf[count], "%s\n", env->envp[i]);
270 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
271 const char *buf, size_t count)
274 enum kobject_action action;
276 if (len && buf[len-1] == '\n')
279 for (action = 0; action < KOBJ_MAX; action++) {
280 if (strncmp(kobject_actions[action], buf, len) != 0)
282 if (kobject_actions[action][len] != '\0')
284 kobject_uevent(&dev->kobj, action);
288 dev_err(dev, "uevent: unsupported action-string; this will "
289 "be ignored in a future kernel version\n");
290 kobject_uevent(&dev->kobj, KOBJ_ADD);
295 static struct device_attribute uevent_attr =
296 __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
298 static int device_add_attributes(struct device *dev,
299 struct device_attribute *attrs)
305 for (i = 0; attr_name(attrs[i]); i++) {
306 error = device_create_file(dev, &attrs[i]);
312 device_remove_file(dev, &attrs[i]);
317 static void device_remove_attributes(struct device *dev,
318 struct device_attribute *attrs)
323 for (i = 0; attr_name(attrs[i]); i++)
324 device_remove_file(dev, &attrs[i]);
327 static int device_add_groups(struct device *dev,
328 struct attribute_group **groups)
334 for (i = 0; groups[i]; i++) {
335 error = sysfs_create_group(&dev->kobj, groups[i]);
338 sysfs_remove_group(&dev->kobj, groups[i]);
346 static void device_remove_groups(struct device *dev,
347 struct attribute_group **groups)
352 for (i = 0; groups[i]; i++)
353 sysfs_remove_group(&dev->kobj, groups[i]);
356 static int device_add_attrs(struct device *dev)
358 struct class *class = dev->class;
359 struct device_type *type = dev->type;
363 error = device_add_attributes(dev, class->dev_attrs);
369 error = device_add_groups(dev, type->groups);
371 goto err_remove_class_attrs;
374 error = device_add_groups(dev, dev->groups);
376 goto err_remove_type_groups;
380 err_remove_type_groups:
382 device_remove_groups(dev, type->groups);
383 err_remove_class_attrs:
385 device_remove_attributes(dev, class->dev_attrs);
390 static void device_remove_attrs(struct device *dev)
392 struct class *class = dev->class;
393 struct device_type *type = dev->type;
395 device_remove_groups(dev, dev->groups);
398 device_remove_groups(dev, type->groups);
401 device_remove_attributes(dev, class->dev_attrs);
405 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
408 return print_dev_t(buf, dev->devt);
411 static struct device_attribute devt_attr =
412 __ATTR(dev, S_IRUGO, show_dev, NULL);
415 * devices_subsys - structure to be registered with kobject core.
418 decl_subsys(devices, &ktype_device, &device_uevent_ops);
422 * device_create_file - create sysfs attribute file for device.
424 * @attr: device attribute descriptor.
427 int device_create_file(struct device * dev, struct device_attribute * attr)
430 if (get_device(dev)) {
431 error = sysfs_create_file(&dev->kobj, &attr->attr);
438 * device_remove_file - remove sysfs attribute file.
440 * @attr: device attribute descriptor.
443 void device_remove_file(struct device * dev, struct device_attribute * attr)
445 if (get_device(dev)) {
446 sysfs_remove_file(&dev->kobj, &attr->attr);
452 * device_create_bin_file - create sysfs binary attribute file for device.
454 * @attr: device binary attribute descriptor.
456 int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
460 error = sysfs_create_bin_file(&dev->kobj, attr);
463 EXPORT_SYMBOL_GPL(device_create_bin_file);
466 * device_remove_bin_file - remove sysfs binary attribute file
468 * @attr: device binary attribute descriptor.
470 void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
473 sysfs_remove_bin_file(&dev->kobj, attr);
475 EXPORT_SYMBOL_GPL(device_remove_bin_file);
478 * device_schedule_callback_owner - helper to schedule a callback for a device
480 * @func: callback function to invoke later.
481 * @owner: module owning the callback routine
483 * Attribute methods must not unregister themselves or their parent device
484 * (which would amount to the same thing). Attempts to do so will deadlock,
485 * since unregistration is mutually exclusive with driver callbacks.
487 * Instead methods can call this routine, which will attempt to allocate
488 * and schedule a workqueue request to call back @func with @dev as its
489 * argument in the workqueue's process context. @dev will be pinned until
492 * This routine is usually called via the inline device_schedule_callback(),
493 * which automatically sets @owner to THIS_MODULE.
495 * Returns 0 if the request was submitted, -ENOMEM if storage could not
496 * be allocated, -ENODEV if a reference to @owner isn't available.
498 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
499 * underlying sysfs routine (since it is intended for use by attribute
500 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
502 int device_schedule_callback_owner(struct device *dev,
503 void (*func)(struct device *), struct module *owner)
505 return sysfs_schedule_callback(&dev->kobj,
506 (void (*)(void *)) func, dev, owner);
508 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
510 static void klist_children_get(struct klist_node *n)
512 struct device *dev = container_of(n, struct device, knode_parent);
517 static void klist_children_put(struct klist_node *n)
519 struct device *dev = container_of(n, struct device, knode_parent);
526 * device_initialize - init device structure.
529 * This prepares the device for use by other layers,
530 * including adding it to the device hierarchy.
531 * It is the first half of device_register(), if called by
532 * that, though it can also be called separately, so one
533 * may use @dev's fields (e.g. the refcount).
536 void device_initialize(struct device *dev)
538 kobj_set_kset_s(dev, devices_subsys);
539 kobject_init(&dev->kobj);
540 klist_init(&dev->klist_children, klist_children_get,
542 INIT_LIST_HEAD(&dev->dma_pools);
543 INIT_LIST_HEAD(&dev->node);
544 init_MUTEX(&dev->sem);
545 spin_lock_init(&dev->devres_lock);
546 INIT_LIST_HEAD(&dev->devres_head);
547 device_init_wakeup(dev, 0);
548 set_dev_node(dev, -1);
551 #ifdef CONFIG_SYSFS_DEPRECATED
552 static struct kobject * get_device_parent(struct device *dev,
553 struct device *parent)
556 * Set the parent to the class, not the parent device
557 * for topmost devices in class hierarchy.
558 * This keeps sysfs from having a symlink to make old
561 if (dev->class && (!parent || parent->class != dev->class))
562 return &dev->class->subsys.kobj;
564 return &parent->kobj;
569 static struct kobject *virtual_device_parent(struct device *dev)
571 static struct kobject *virtual_dir = NULL;
574 virtual_dir = kobject_add_dir(&devices_subsys.kobj, "virtual");
579 static struct kobject * get_device_parent(struct device *dev,
580 struct device *parent)
583 struct kobject *kobj = NULL;
584 struct kobject *parent_kobj;
588 * If we have no parent, we live in "virtual".
589 * Class-devices with a bus-device as parent, live
590 * in a class-directory to prevent namespace collisions.
593 parent_kobj = virtual_device_parent(dev);
594 else if (parent->class)
595 return &parent->kobj;
597 parent_kobj = &parent->kobj;
599 /* find our class-directory at the parent and reference it */
600 spin_lock(&dev->class->class_dirs.list_lock);
601 list_for_each_entry(k, &dev->class->class_dirs.list, entry)
602 if (k->parent == parent_kobj) {
603 kobj = kobject_get(k);
606 spin_unlock(&dev->class->class_dirs.list_lock);
610 /* or create a new class-directory at the parent device */
611 return kobject_kset_add_dir(&dev->class->class_dirs,
612 parent_kobj, dev->class->name);
616 return &parent->kobj;
621 static int setup_parent(struct device *dev, struct device *parent)
623 struct kobject *kobj;
624 kobj = get_device_parent(dev, parent);
626 return PTR_ERR(kobj);
628 dev->kobj.parent = kobj;
632 static int device_add_class_symlinks(struct device *dev)
638 error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
643 * If this is not a "fake" compatible device, then create the
644 * symlink from the class to the device.
646 if (dev->kobj.parent != &dev->class->subsys.kobj) {
647 error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
653 #ifdef CONFIG_SYSFS_DEPRECATED
655 struct device *parent = dev->parent;
659 * In old sysfs stacked class devices had 'device'
660 * link pointing to real device instead of parent
662 while (parent->class && !parent->bus && parent->parent)
663 parent = parent->parent;
665 error = sysfs_create_link(&dev->kobj,
671 class_name = make_class_name(dev->class->name,
674 error = sysfs_create_link(&dev->parent->kobj,
675 &dev->kobj, class_name);
681 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
689 #ifdef CONFIG_SYSFS_DEPRECATED
692 sysfs_remove_link(&dev->kobj, "device");
695 if (dev->kobj.parent != &dev->class->subsys.kobj)
696 sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
698 sysfs_remove_link(&dev->kobj, "subsystem");
703 static void device_remove_class_symlinks(struct device *dev)
708 #ifdef CONFIG_SYSFS_DEPRECATED
711 class_name = make_class_name(dev->class->name, &dev->kobj);
713 sysfs_remove_link(&dev->parent->kobj, class_name);
717 sysfs_remove_link(&dev->kobj, "device");
719 if (dev->kobj.parent != &dev->class->subsys.kobj)
720 sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
721 sysfs_remove_link(&dev->kobj, "subsystem");
725 * device_add - add device to device hierarchy.
728 * This is part 2 of device_register(), though may be called
729 * separately _iff_ device_initialize() has been called separately.
731 * This adds it to the kobject hierarchy via kobject_add(), adds it
732 * to the global and sibling lists for the device, then
733 * adds it to the other relevant subsystems of the driver model.
735 int device_add(struct device *dev)
737 struct device *parent = NULL;
738 struct class_interface *class_intf;
741 dev = get_device(dev);
742 if (!dev || !strlen(dev->bus_id))
745 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
747 parent = get_device(dev->parent);
748 error = setup_parent(dev, parent);
752 /* first, register with generic layer. */
753 kobject_set_name(&dev->kobj, "%s", dev->bus_id);
754 error = kobject_add(&dev->kobj);
758 /* notify platform of device entry */
760 platform_notify(dev);
762 /* notify clients of device entry (new way) */
764 blocking_notifier_call_chain(&dev->bus->bus_notifier,
765 BUS_NOTIFY_ADD_DEVICE, dev);
767 error = device_create_file(dev, &uevent_attr);
771 if (MAJOR(dev->devt)) {
772 error = device_create_file(dev, &devt_attr);
774 goto ueventattrError;
777 error = device_add_class_symlinks(dev);
780 error = device_add_attrs(dev);
783 error = device_pm_add(dev);
786 error = bus_add_device(dev);
789 kobject_uevent(&dev->kobj, KOBJ_ADD);
790 bus_attach_device(dev);
792 klist_add_tail(&dev->knode_parent, &parent->klist_children);
795 down(&dev->class->sem);
796 /* tie the class to the device */
797 list_add_tail(&dev->node, &dev->class->devices);
799 /* notify any interfaces that the device is here */
800 list_for_each_entry(class_intf, &dev->class->interfaces, node)
801 if (class_intf->add_dev)
802 class_intf->add_dev(dev, class_intf);
803 up(&dev->class->sem);
809 device_pm_remove(dev);
812 blocking_notifier_call_chain(&dev->bus->bus_notifier,
813 BUS_NOTIFY_DEL_DEVICE, dev);
814 device_remove_attrs(dev);
816 device_remove_class_symlinks(dev);
818 if (MAJOR(dev->devt))
819 device_remove_file(dev, &devt_attr);
822 sysfs_remove_link(&dev->kobj, "subsystem");
823 /* If this is not a "fake" compatible device, remove the
824 * symlink from the class to the device. */
825 if (dev->kobj.parent != &dev->class->subsys.kobj)
826 sysfs_remove_link(&dev->class->subsys.kobj,
829 #ifdef CONFIG_SYSFS_DEPRECATED
830 char *class_name = make_class_name(dev->class->name,
833 sysfs_remove_link(&dev->parent->kobj,
837 sysfs_remove_link(&dev->kobj, "device");
841 device_remove_file(dev, &uevent_attr);
843 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
844 kobject_del(&dev->kobj);
853 * device_register - register a device with the system.
854 * @dev: pointer to the device structure
856 * This happens in two clean steps - initialize the device
857 * and add it to the system. The two steps can be called
858 * separately, but this is the easiest and most common.
859 * I.e. you should only call the two helpers separately if
860 * have a clearly defined need to use and refcount the device
861 * before it is added to the hierarchy.
864 int device_register(struct device *dev)
866 device_initialize(dev);
867 return device_add(dev);
872 * get_device - increment reference count for device.
875 * This simply forwards the call to kobject_get(), though
876 * we do take care to provide for the case that we get a NULL
880 struct device * get_device(struct device * dev)
882 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
887 * put_device - decrement reference count.
888 * @dev: device in question.
890 void put_device(struct device * dev)
893 kobject_put(&dev->kobj);
898 * device_del - delete device from system.
901 * This is the first part of the device unregistration
902 * sequence. This removes the device from the lists we control
903 * from here, has it removed from the other driver model
904 * subsystems it was added to in device_add(), and removes it
905 * from the kobject hierarchy.
907 * NOTE: this should be called manually _iff_ device_add() was
908 * also called manually.
911 void device_del(struct device * dev)
913 struct device * parent = dev->parent;
914 struct class_interface *class_intf;
917 klist_del(&dev->knode_parent);
918 if (MAJOR(dev->devt))
919 device_remove_file(dev, &devt_attr);
921 sysfs_remove_link(&dev->kobj, "subsystem");
922 /* If this is not a "fake" compatible device, remove the
923 * symlink from the class to the device. */
924 if (dev->kobj.parent != &dev->class->subsys.kobj)
925 sysfs_remove_link(&dev->class->subsys.kobj,
928 #ifdef CONFIG_SYSFS_DEPRECATED
929 char *class_name = make_class_name(dev->class->name,
932 sysfs_remove_link(&dev->parent->kobj,
936 sysfs_remove_link(&dev->kobj, "device");
939 down(&dev->class->sem);
940 /* notify any interfaces that the device is now gone */
941 list_for_each_entry(class_intf, &dev->class->interfaces, node)
942 if (class_intf->remove_dev)
943 class_intf->remove_dev(dev, class_intf);
944 /* remove the device from the class list */
945 list_del_init(&dev->node);
946 up(&dev->class->sem);
948 /* If we live in a parent class-directory, unreference it */
949 if (dev->kobj.parent->kset == &dev->class->class_dirs) {
954 * if we are the last child of our class, delete
955 * our class-directory at this parent
957 down(&dev->class->sem);
958 list_for_each_entry(d, &dev->class->devices, node) {
961 if (d->kobj.parent == dev->kobj.parent) {
967 kobject_del(dev->kobj.parent);
969 kobject_put(dev->kobj.parent);
970 up(&dev->class->sem);
973 device_remove_file(dev, &uevent_attr);
974 device_remove_attrs(dev);
975 bus_remove_device(dev);
978 * Some platform devices are driven without driver attached
979 * and managed resources may have been acquired. Make sure
980 * all resources are released.
982 devres_release_all(dev);
984 /* Notify the platform of the removal, in case they
985 * need to do anything...
987 if (platform_notify_remove)
988 platform_notify_remove(dev);
990 blocking_notifier_call_chain(&dev->bus->bus_notifier,
991 BUS_NOTIFY_DEL_DEVICE, dev);
992 device_pm_remove(dev);
993 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
994 kobject_del(&dev->kobj);
1000 * device_unregister - unregister device from system.
1001 * @dev: device going away.
1003 * We do this in two parts, like we do device_register(). First,
1004 * we remove it from all the subsystems with device_del(), then
1005 * we decrement the reference count via put_device(). If that
1006 * is the final reference count, the device will be cleaned up
1007 * via device_release() above. Otherwise, the structure will
1008 * stick around until the final reference to the device is dropped.
1010 void device_unregister(struct device * dev)
1012 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
1018 static struct device * next_device(struct klist_iter * i)
1020 struct klist_node * n = klist_next(i);
1021 return n ? container_of(n, struct device, knode_parent) : NULL;
1025 * device_for_each_child - device child iterator.
1026 * @parent: parent struct device.
1027 * @data: data for the callback.
1028 * @fn: function to be called for each device.
1030 * Iterate over @parent's child devices, and call @fn for each,
1033 * We check the return of @fn each time. If it returns anything
1034 * other than 0, we break out and return that value.
1036 int device_for_each_child(struct device * parent, void * data,
1037 int (*fn)(struct device *, void *))
1039 struct klist_iter i;
1040 struct device * child;
1043 klist_iter_init(&parent->klist_children, &i);
1044 while ((child = next_device(&i)) && !error)
1045 error = fn(child, data);
1046 klist_iter_exit(&i);
1051 * device_find_child - device iterator for locating a particular device.
1052 * @parent: parent struct device
1053 * @data: Data to pass to match function
1054 * @match: Callback function to check device
1056 * This is similar to the device_for_each_child() function above, but it
1057 * returns a reference to a device that is 'found' for later use, as
1058 * determined by the @match callback.
1060 * The callback should return 0 if the device doesn't match and non-zero
1061 * if it does. If the callback returns non-zero and a reference to the
1062 * current device can be obtained, this function will return to the caller
1063 * and not iterate over any more devices.
1065 struct device * device_find_child(struct device *parent, void *data,
1066 int (*match)(struct device *, void *))
1068 struct klist_iter i;
1069 struct device *child;
1074 klist_iter_init(&parent->klist_children, &i);
1075 while ((child = next_device(&i)))
1076 if (match(child, data) && get_device(child))
1078 klist_iter_exit(&i);
1082 int __init devices_init(void)
1084 return subsystem_register(&devices_subsys);
1087 EXPORT_SYMBOL_GPL(device_for_each_child);
1088 EXPORT_SYMBOL_GPL(device_find_child);
1090 EXPORT_SYMBOL_GPL(device_initialize);
1091 EXPORT_SYMBOL_GPL(device_add);
1092 EXPORT_SYMBOL_GPL(device_register);
1094 EXPORT_SYMBOL_GPL(device_del);
1095 EXPORT_SYMBOL_GPL(device_unregister);
1096 EXPORT_SYMBOL_GPL(get_device);
1097 EXPORT_SYMBOL_GPL(put_device);
1099 EXPORT_SYMBOL_GPL(device_create_file);
1100 EXPORT_SYMBOL_GPL(device_remove_file);
1103 static void device_create_release(struct device *dev)
1105 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
1110 * device_create - creates a device and registers it with sysfs
1111 * @class: pointer to the struct class that this device should be registered to
1112 * @parent: pointer to the parent struct device of this new device, if any
1113 * @devt: the dev_t for the char device to be added
1114 * @fmt: string for the device's name
1116 * This function can be used by char device classes. A struct device
1117 * will be created in sysfs, registered to the specified class.
1119 * A "dev" file will be created, showing the dev_t for the device, if
1120 * the dev_t is not 0,0.
1121 * If a pointer to a parent struct device is passed in, the newly created
1122 * struct device will be a child of that device in sysfs.
1123 * The pointer to the struct device will be returned from the call.
1124 * Any further sysfs files that might be required can be created using this
1127 * Note: the struct class passed to this function must have previously
1128 * been created with a call to class_create().
1130 struct device *device_create(struct class *class, struct device *parent,
1131 dev_t devt, const char *fmt, ...)
1134 struct device *dev = NULL;
1135 int retval = -ENODEV;
1137 if (class == NULL || IS_ERR(class))
1140 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1148 dev->parent = parent;
1149 dev->release = device_create_release;
1151 va_start(args, fmt);
1152 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
1154 retval = device_register(dev);
1162 return ERR_PTR(retval);
1164 EXPORT_SYMBOL_GPL(device_create);
1167 * device_destroy - removes a device that was created with device_create()
1168 * @class: pointer to the struct class that this device was registered with
1169 * @devt: the dev_t of the device that was previously registered
1171 * This call unregisters and cleans up a device that was created with a
1172 * call to device_create().
1174 void device_destroy(struct class *class, dev_t devt)
1176 struct device *dev = NULL;
1177 struct device *dev_tmp;
1180 list_for_each_entry(dev_tmp, &class->devices, node) {
1181 if (dev_tmp->devt == devt) {
1189 device_unregister(dev);
1191 EXPORT_SYMBOL_GPL(device_destroy);
1194 * device_rename - renames a device
1195 * @dev: the pointer to the struct device to be renamed
1196 * @new_name: the new name of the device
1198 int device_rename(struct device *dev, char *new_name)
1200 char *old_class_name = NULL;
1201 char *new_class_name = NULL;
1202 char *old_device_name = NULL;
1205 dev = get_device(dev);
1209 pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name);
1211 #ifdef CONFIG_SYSFS_DEPRECATED
1212 if ((dev->class) && (dev->parent))
1213 old_class_name = make_class_name(dev->class->name, &dev->kobj);
1216 old_device_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
1217 if (!old_device_name) {
1221 strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
1222 strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
1224 error = kobject_rename(&dev->kobj, new_name);
1226 strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
1230 #ifdef CONFIG_SYSFS_DEPRECATED
1231 if (old_class_name) {
1232 new_class_name = make_class_name(dev->class->name, &dev->kobj);
1233 if (new_class_name) {
1234 error = sysfs_create_link(&dev->parent->kobj,
1235 &dev->kobj, new_class_name);
1238 sysfs_remove_link(&dev->parent->kobj, old_class_name);
1244 sysfs_remove_link(&dev->class->subsys.kobj, old_device_name);
1245 error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
1248 /* Uh... how to unravel this if restoring can fail? */
1249 dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n",
1250 __FUNCTION__, error);
1256 kfree(new_class_name);
1257 kfree(old_class_name);
1258 kfree(old_device_name);
1262 EXPORT_SYMBOL_GPL(device_rename);
1264 static int device_move_class_links(struct device *dev,
1265 struct device *old_parent,
1266 struct device *new_parent)
1269 #ifdef CONFIG_SYSFS_DEPRECATED
1272 class_name = make_class_name(dev->class->name, &dev->kobj);
1278 sysfs_remove_link(&dev->kobj, "device");
1279 sysfs_remove_link(&old_parent->kobj, class_name);
1282 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1286 error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
1289 sysfs_remove_link(&dev->kobj, "device");
1298 sysfs_remove_link(&dev->kobj, "device");
1300 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1307 * device_move - moves a device to a new parent
1308 * @dev: the pointer to the struct device to be moved
1309 * @new_parent: the new parent of the device (can by NULL)
1311 int device_move(struct device *dev, struct device *new_parent)
1314 struct device *old_parent;
1315 struct kobject *new_parent_kobj;
1317 dev = get_device(dev);
1321 new_parent = get_device(new_parent);
1322 new_parent_kobj = get_device_parent (dev, new_parent);
1323 if (IS_ERR(new_parent_kobj)) {
1324 error = PTR_ERR(new_parent_kobj);
1325 put_device(new_parent);
1328 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
1329 new_parent ? new_parent->bus_id : "<NULL>");
1330 error = kobject_move(&dev->kobj, new_parent_kobj);
1332 put_device(new_parent);
1335 old_parent = dev->parent;
1336 dev->parent = new_parent;
1338 klist_remove(&dev->knode_parent);
1340 klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1343 error = device_move_class_links(dev, old_parent, new_parent);
1345 /* We ignore errors on cleanup since we're hosed anyway... */
1346 device_move_class_links(dev, new_parent, old_parent);
1347 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1349 klist_remove(&dev->knode_parent);
1351 klist_add_tail(&dev->knode_parent,
1352 &old_parent->klist_children);
1354 put_device(new_parent);
1358 put_device(old_parent);
1364 EXPORT_SYMBOL_GPL(device_move);