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 device_ktype = {
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 == &device_ktype) {
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 while (!top_kobj->kset && top_kobj->parent)
238 top_kobj = top_kobj->parent;
242 kset = top_kobj->kset;
243 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
247 if (kset->uevent_ops && kset->uevent_ops->filter)
248 if (!kset->uevent_ops->filter(kset, &dev->kobj))
251 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
255 /* let the kset specific function add its keys */
256 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
260 /* copy keys to file */
261 for (i = 0; i < env->envp_idx; i++)
262 count += sprintf(&buf[count], "%s\n", env->envp[i]);
268 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
269 const char *buf, size_t count)
271 enum kobject_action action;
273 if (kobject_action_type(buf, count, &action) == 0) {
274 kobject_uevent(&dev->kobj, action);
278 dev_err(dev, "uevent: unsupported action-string; this will "
279 "be ignored in a future kernel version\n");
280 kobject_uevent(&dev->kobj, KOBJ_ADD);
285 static struct device_attribute uevent_attr =
286 __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
288 static int device_add_attributes(struct device *dev,
289 struct device_attribute *attrs)
295 for (i = 0; attr_name(attrs[i]); i++) {
296 error = device_create_file(dev, &attrs[i]);
302 device_remove_file(dev, &attrs[i]);
307 static void device_remove_attributes(struct device *dev,
308 struct device_attribute *attrs)
313 for (i = 0; attr_name(attrs[i]); i++)
314 device_remove_file(dev, &attrs[i]);
317 static int device_add_groups(struct device *dev,
318 struct attribute_group **groups)
324 for (i = 0; groups[i]; i++) {
325 error = sysfs_create_group(&dev->kobj, groups[i]);
328 sysfs_remove_group(&dev->kobj, groups[i]);
336 static void device_remove_groups(struct device *dev,
337 struct attribute_group **groups)
342 for (i = 0; groups[i]; i++)
343 sysfs_remove_group(&dev->kobj, groups[i]);
346 static int device_add_attrs(struct device *dev)
348 struct class *class = dev->class;
349 struct device_type *type = dev->type;
353 error = device_add_attributes(dev, class->dev_attrs);
359 error = device_add_groups(dev, type->groups);
361 goto err_remove_class_attrs;
364 error = device_add_groups(dev, dev->groups);
366 goto err_remove_type_groups;
370 err_remove_type_groups:
372 device_remove_groups(dev, type->groups);
373 err_remove_class_attrs:
375 device_remove_attributes(dev, class->dev_attrs);
380 static void device_remove_attrs(struct device *dev)
382 struct class *class = dev->class;
383 struct device_type *type = dev->type;
385 device_remove_groups(dev, dev->groups);
388 device_remove_groups(dev, type->groups);
391 device_remove_attributes(dev, class->dev_attrs);
395 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
398 return print_dev_t(buf, dev->devt);
401 static struct device_attribute devt_attr =
402 __ATTR(dev, S_IRUGO, show_dev, NULL);
404 /* kset to create /sys/devices/ */
405 struct kset *devices_kset;
409 * device_create_file - create sysfs attribute file for device.
411 * @attr: device attribute descriptor.
414 int device_create_file(struct device * dev, struct device_attribute * attr)
417 if (get_device(dev)) {
418 error = sysfs_create_file(&dev->kobj, &attr->attr);
425 * device_remove_file - remove sysfs attribute file.
427 * @attr: device attribute descriptor.
430 void device_remove_file(struct device * dev, struct device_attribute * attr)
432 if (get_device(dev)) {
433 sysfs_remove_file(&dev->kobj, &attr->attr);
439 * device_create_bin_file - create sysfs binary attribute file for device.
441 * @attr: device binary attribute descriptor.
443 int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
447 error = sysfs_create_bin_file(&dev->kobj, attr);
450 EXPORT_SYMBOL_GPL(device_create_bin_file);
453 * device_remove_bin_file - remove sysfs binary attribute file
455 * @attr: device binary attribute descriptor.
457 void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
460 sysfs_remove_bin_file(&dev->kobj, attr);
462 EXPORT_SYMBOL_GPL(device_remove_bin_file);
465 * device_schedule_callback_owner - helper to schedule a callback for a device
467 * @func: callback function to invoke later.
468 * @owner: module owning the callback routine
470 * Attribute methods must not unregister themselves or their parent device
471 * (which would amount to the same thing). Attempts to do so will deadlock,
472 * since unregistration is mutually exclusive with driver callbacks.
474 * Instead methods can call this routine, which will attempt to allocate
475 * and schedule a workqueue request to call back @func with @dev as its
476 * argument in the workqueue's process context. @dev will be pinned until
479 * This routine is usually called via the inline device_schedule_callback(),
480 * which automatically sets @owner to THIS_MODULE.
482 * Returns 0 if the request was submitted, -ENOMEM if storage could not
483 * be allocated, -ENODEV if a reference to @owner isn't available.
485 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
486 * underlying sysfs routine (since it is intended for use by attribute
487 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
489 int device_schedule_callback_owner(struct device *dev,
490 void (*func)(struct device *), struct module *owner)
492 return sysfs_schedule_callback(&dev->kobj,
493 (void (*)(void *)) func, dev, owner);
495 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
497 static void klist_children_get(struct klist_node *n)
499 struct device *dev = container_of(n, struct device, knode_parent);
504 static void klist_children_put(struct klist_node *n)
506 struct device *dev = container_of(n, struct device, knode_parent);
513 * device_initialize - init device structure.
516 * This prepares the device for use by other layers,
517 * including adding it to the device hierarchy.
518 * It is the first half of device_register(), if called by
519 * that, though it can also be called separately, so one
520 * may use @dev's fields (e.g. the refcount).
523 void device_initialize(struct device *dev)
525 dev->kobj.kset = devices_kset;
526 dev->kobj.ktype = &device_ktype;
527 kobject_init(&dev->kobj);
528 klist_init(&dev->klist_children, klist_children_get,
530 INIT_LIST_HEAD(&dev->dma_pools);
531 INIT_LIST_HEAD(&dev->node);
532 init_MUTEX(&dev->sem);
533 spin_lock_init(&dev->devres_lock);
534 INIT_LIST_HEAD(&dev->devres_head);
535 device_init_wakeup(dev, 0);
536 set_dev_node(dev, -1);
539 #ifdef CONFIG_SYSFS_DEPRECATED
540 static struct kobject * get_device_parent(struct device *dev,
541 struct device *parent)
544 * Set the parent to the class, not the parent device
545 * for topmost devices in class hierarchy.
546 * This keeps sysfs from having a symlink to make old
549 if (dev->class && (!parent || parent->class != dev->class))
550 return &dev->class->subsys.kobj;
552 return &parent->kobj;
557 static struct kobject *virtual_device_parent(struct device *dev)
559 static struct kobject *virtual_dir = NULL;
562 virtual_dir = kobject_create_and_add("virtual",
563 &devices_kset->kobj);
568 static struct kobject * get_device_parent(struct device *dev,
569 struct device *parent)
574 struct kobject *kobj = NULL;
575 struct kobject *parent_kobj;
579 * If we have no parent, we live in "virtual".
580 * Class-devices with a bus-device as parent, live
581 * in a class-directory to prevent namespace collisions.
584 parent_kobj = virtual_device_parent(dev);
585 else if (parent->class)
586 return &parent->kobj;
588 parent_kobj = &parent->kobj;
590 /* find our class-directory at the parent and reference it */
591 spin_lock(&dev->class->class_dirs.list_lock);
592 list_for_each_entry(k, &dev->class->class_dirs.list, entry)
593 if (k->parent == parent_kobj) {
594 kobj = kobject_get(k);
597 spin_unlock(&dev->class->class_dirs.list_lock);
601 /* or create a new class-directory at the parent device */
602 k = kobject_create();
605 k->kset = &dev->class->class_dirs;
606 retval = kobject_add_ng(k, parent_kobj, "%s", dev->class->name);
611 /* Do not emit a uevent, as it's not needed for this
612 * "class glue" directory. */
617 return &parent->kobj;
622 static int setup_parent(struct device *dev, struct device *parent)
624 struct kobject *kobj;
625 kobj = get_device_parent(dev, parent);
627 return PTR_ERR(kobj);
629 dev->kobj.parent = kobj;
633 static int device_add_class_symlinks(struct device *dev)
639 error = sysfs_create_link(&dev->kobj, &dev->class->subsys.kobj,
644 * If this is not a "fake" compatible device, then create the
645 * symlink from the class to the device.
647 if (dev->kobj.parent != &dev->class->subsys.kobj) {
648 error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
654 #ifdef CONFIG_SYSFS_DEPRECATED
656 struct device *parent = dev->parent;
660 * In old sysfs stacked class devices had 'device'
661 * link pointing to real device instead of parent
663 while (parent->class && !parent->bus && parent->parent)
664 parent = parent->parent;
666 error = sysfs_create_link(&dev->kobj,
672 class_name = make_class_name(dev->class->name,
675 error = sysfs_create_link(&dev->parent->kobj,
676 &dev->kobj, class_name);
682 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
690 #ifdef CONFIG_SYSFS_DEPRECATED
693 sysfs_remove_link(&dev->kobj, "device");
696 if (dev->kobj.parent != &dev->class->subsys.kobj)
697 sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
699 sysfs_remove_link(&dev->kobj, "subsystem");
704 static void device_remove_class_symlinks(struct device *dev)
709 #ifdef CONFIG_SYSFS_DEPRECATED
712 class_name = make_class_name(dev->class->name, &dev->kobj);
714 sysfs_remove_link(&dev->parent->kobj, class_name);
718 sysfs_remove_link(&dev->kobj, "device");
720 if (dev->kobj.parent != &dev->class->subsys.kobj)
721 sysfs_remove_link(&dev->class->subsys.kobj, dev->bus_id);
722 sysfs_remove_link(&dev->kobj, "subsystem");
726 * device_add - add device to device hierarchy.
729 * This is part 2 of device_register(), though may be called
730 * separately _iff_ device_initialize() has been called separately.
732 * This adds it to the kobject hierarchy via kobject_add(), adds it
733 * to the global and sibling lists for the device, then
734 * adds it to the other relevant subsystems of the driver model.
736 int device_add(struct device *dev)
738 struct device *parent = NULL;
739 struct class_interface *class_intf;
742 error = pm_sleep_lock();
744 dev_warn(dev, "Suspicious %s during suspend\n", __FUNCTION__);
749 dev = get_device(dev);
750 if (!dev || !strlen(dev->bus_id)) {
755 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
757 parent = get_device(dev->parent);
758 error = setup_parent(dev, parent);
762 /* first, register with generic layer. */
763 kobject_set_name(&dev->kobj, "%s", dev->bus_id);
764 error = kobject_add(&dev->kobj);
768 /* notify platform of device entry */
770 platform_notify(dev);
772 /* notify clients of device entry (new way) */
774 blocking_notifier_call_chain(&dev->bus->bus_notifier,
775 BUS_NOTIFY_ADD_DEVICE, dev);
777 error = device_create_file(dev, &uevent_attr);
781 if (MAJOR(dev->devt)) {
782 error = device_create_file(dev, &devt_attr);
784 goto ueventattrError;
787 error = device_add_class_symlinks(dev);
790 error = device_add_attrs(dev);
793 error = dpm_sysfs_add(dev);
797 error = bus_add_device(dev);
800 kobject_uevent(&dev->kobj, KOBJ_ADD);
801 bus_attach_device(dev);
803 klist_add_tail(&dev->knode_parent, &parent->klist_children);
806 down(&dev->class->sem);
807 /* tie the class to the device */
808 list_add_tail(&dev->node, &dev->class->devices);
810 /* notify any interfaces that the device is here */
811 list_for_each_entry(class_intf, &dev->class->interfaces, node)
812 if (class_intf->add_dev)
813 class_intf->add_dev(dev, class_intf);
814 up(&dev->class->sem);
821 device_pm_remove(dev);
822 dpm_sysfs_remove(dev);
825 blocking_notifier_call_chain(&dev->bus->bus_notifier,
826 BUS_NOTIFY_DEL_DEVICE, dev);
827 device_remove_attrs(dev);
829 device_remove_class_symlinks(dev);
831 if (MAJOR(dev->devt))
832 device_remove_file(dev, &devt_attr);
835 sysfs_remove_link(&dev->kobj, "subsystem");
836 /* If this is not a "fake" compatible device, remove the
837 * symlink from the class to the device. */
838 if (dev->kobj.parent != &dev->class->subsys.kobj)
839 sysfs_remove_link(&dev->class->subsys.kobj,
842 #ifdef CONFIG_SYSFS_DEPRECATED
843 char *class_name = make_class_name(dev->class->name,
846 sysfs_remove_link(&dev->parent->kobj,
850 sysfs_remove_link(&dev->kobj, "device");
854 device_remove_file(dev, &uevent_attr);
856 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
857 kobject_del(&dev->kobj);
866 * device_register - register a device with the system.
867 * @dev: pointer to the device structure
869 * This happens in two clean steps - initialize the device
870 * and add it to the system. The two steps can be called
871 * separately, but this is the easiest and most common.
872 * I.e. you should only call the two helpers separately if
873 * have a clearly defined need to use and refcount the device
874 * before it is added to the hierarchy.
877 int device_register(struct device *dev)
879 device_initialize(dev);
880 return device_add(dev);
885 * get_device - increment reference count for device.
888 * This simply forwards the call to kobject_get(), though
889 * we do take care to provide for the case that we get a NULL
893 struct device * get_device(struct device * dev)
895 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
900 * put_device - decrement reference count.
901 * @dev: device in question.
903 void put_device(struct device * dev)
906 kobject_put(&dev->kobj);
911 * device_del - delete device from system.
914 * This is the first part of the device unregistration
915 * sequence. This removes the device from the lists we control
916 * from here, has it removed from the other driver model
917 * subsystems it was added to in device_add(), and removes it
918 * from the kobject hierarchy.
920 * NOTE: this should be called manually _iff_ device_add() was
921 * also called manually.
924 void device_del(struct device * dev)
926 struct device * parent = dev->parent;
927 struct class_interface *class_intf;
929 device_pm_remove(dev);
931 klist_del(&dev->knode_parent);
932 if (MAJOR(dev->devt))
933 device_remove_file(dev, &devt_attr);
935 sysfs_remove_link(&dev->kobj, "subsystem");
936 /* If this is not a "fake" compatible device, remove the
937 * symlink from the class to the device. */
938 if (dev->kobj.parent != &dev->class->subsys.kobj)
939 sysfs_remove_link(&dev->class->subsys.kobj,
942 #ifdef CONFIG_SYSFS_DEPRECATED
943 char *class_name = make_class_name(dev->class->name,
946 sysfs_remove_link(&dev->parent->kobj,
950 sysfs_remove_link(&dev->kobj, "device");
953 down(&dev->class->sem);
954 /* notify any interfaces that the device is now gone */
955 list_for_each_entry(class_intf, &dev->class->interfaces, node)
956 if (class_intf->remove_dev)
957 class_intf->remove_dev(dev, class_intf);
958 /* remove the device from the class list */
959 list_del_init(&dev->node);
960 up(&dev->class->sem);
962 /* If we live in a parent class-directory, unreference it */
963 if (dev->kobj.parent->kset == &dev->class->class_dirs) {
968 * if we are the last child of our class, delete
969 * our class-directory at this parent
971 down(&dev->class->sem);
972 list_for_each_entry(d, &dev->class->devices, node) {
975 if (d->kobj.parent == dev->kobj.parent) {
981 kobject_del(dev->kobj.parent);
983 kobject_put(dev->kobj.parent);
984 up(&dev->class->sem);
987 device_remove_file(dev, &uevent_attr);
988 device_remove_attrs(dev);
989 bus_remove_device(dev);
992 * Some platform devices are driven without driver attached
993 * and managed resources may have been acquired. Make sure
994 * all resources are released.
996 devres_release_all(dev);
998 /* Notify the platform of the removal, in case they
999 * need to do anything...
1001 if (platform_notify_remove)
1002 platform_notify_remove(dev);
1004 blocking_notifier_call_chain(&dev->bus->bus_notifier,
1005 BUS_NOTIFY_DEL_DEVICE, dev);
1006 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1007 kobject_del(&dev->kobj);
1013 * device_unregister - unregister device from system.
1014 * @dev: device going away.
1016 * We do this in two parts, like we do device_register(). First,
1017 * we remove it from all the subsystems with device_del(), then
1018 * we decrement the reference count via put_device(). If that
1019 * is the final reference count, the device will be cleaned up
1020 * via device_release() above. Otherwise, the structure will
1021 * stick around until the final reference to the device is dropped.
1023 void device_unregister(struct device * dev)
1025 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
1031 static struct device * next_device(struct klist_iter * i)
1033 struct klist_node * n = klist_next(i);
1034 return n ? container_of(n, struct device, knode_parent) : NULL;
1038 * device_for_each_child - device child iterator.
1039 * @parent: parent struct device.
1040 * @data: data for the callback.
1041 * @fn: function to be called for each device.
1043 * Iterate over @parent's child devices, and call @fn for each,
1046 * We check the return of @fn each time. If it returns anything
1047 * other than 0, we break out and return that value.
1049 int device_for_each_child(struct device * parent, void * data,
1050 int (*fn)(struct device *, void *))
1052 struct klist_iter i;
1053 struct device * child;
1056 klist_iter_init(&parent->klist_children, &i);
1057 while ((child = next_device(&i)) && !error)
1058 error = fn(child, data);
1059 klist_iter_exit(&i);
1064 * device_find_child - device iterator for locating a particular device.
1065 * @parent: parent struct device
1066 * @data: Data to pass to match function
1067 * @match: Callback function to check device
1069 * This is similar to the device_for_each_child() function above, but it
1070 * returns a reference to a device that is 'found' for later use, as
1071 * determined by the @match callback.
1073 * The callback should return 0 if the device doesn't match and non-zero
1074 * if it does. If the callback returns non-zero and a reference to the
1075 * current device can be obtained, this function will return to the caller
1076 * and not iterate over any more devices.
1078 struct device * device_find_child(struct device *parent, void *data,
1079 int (*match)(struct device *, void *))
1081 struct klist_iter i;
1082 struct device *child;
1087 klist_iter_init(&parent->klist_children, &i);
1088 while ((child = next_device(&i)))
1089 if (match(child, data) && get_device(child))
1091 klist_iter_exit(&i);
1095 int __init devices_init(void)
1097 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1103 EXPORT_SYMBOL_GPL(device_for_each_child);
1104 EXPORT_SYMBOL_GPL(device_find_child);
1106 EXPORT_SYMBOL_GPL(device_initialize);
1107 EXPORT_SYMBOL_GPL(device_add);
1108 EXPORT_SYMBOL_GPL(device_register);
1110 EXPORT_SYMBOL_GPL(device_del);
1111 EXPORT_SYMBOL_GPL(device_unregister);
1112 EXPORT_SYMBOL_GPL(get_device);
1113 EXPORT_SYMBOL_GPL(put_device);
1115 EXPORT_SYMBOL_GPL(device_create_file);
1116 EXPORT_SYMBOL_GPL(device_remove_file);
1119 static void device_create_release(struct device *dev)
1121 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
1126 * device_create - creates a device and registers it with sysfs
1127 * @class: pointer to the struct class that this device should be registered to
1128 * @parent: pointer to the parent struct device of this new device, if any
1129 * @devt: the dev_t for the char device to be added
1130 * @fmt: string for the device's name
1132 * This function can be used by char device classes. A struct device
1133 * will be created in sysfs, registered to the specified class.
1135 * A "dev" file will be created, showing the dev_t for the device, if
1136 * the dev_t is not 0,0.
1137 * If a pointer to a parent struct device is passed in, the newly created
1138 * struct device will be a child of that device in sysfs.
1139 * The pointer to the struct device will be returned from the call.
1140 * Any further sysfs files that might be required can be created using this
1143 * Note: the struct class passed to this function must have previously
1144 * been created with a call to class_create().
1146 struct device *device_create(struct class *class, struct device *parent,
1147 dev_t devt, const char *fmt, ...)
1150 struct device *dev = NULL;
1151 int retval = -ENODEV;
1153 if (class == NULL || IS_ERR(class))
1156 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1164 dev->parent = parent;
1165 dev->release = device_create_release;
1167 va_start(args, fmt);
1168 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
1170 retval = device_register(dev);
1178 return ERR_PTR(retval);
1180 EXPORT_SYMBOL_GPL(device_create);
1183 * find_device - finds a device that was created with device_create()
1184 * @class: pointer to the struct class that this device was registered with
1185 * @devt: the dev_t of the device that was previously registered
1187 static struct device *find_device(struct class *class, dev_t devt)
1189 struct device *dev = NULL;
1190 struct device *dev_tmp;
1193 list_for_each_entry(dev_tmp, &class->devices, node) {
1194 if (dev_tmp->devt == devt) {
1204 * device_destroy - removes a device that was created with device_create()
1205 * @class: pointer to the struct class that this device was registered with
1206 * @devt: the dev_t of the device that was previously registered
1208 * This call unregisters and cleans up a device that was created with a
1209 * call to device_create().
1211 void device_destroy(struct class *class, dev_t devt)
1215 dev = find_device(class, devt);
1217 device_unregister(dev);
1219 EXPORT_SYMBOL_GPL(device_destroy);
1221 #ifdef CONFIG_PM_SLEEP
1223 * destroy_suspended_device - asks the PM core to remove a suspended device
1224 * @class: pointer to the struct class that this device was registered with
1225 * @devt: the dev_t of the device that was previously registered
1227 * This call notifies the PM core of the necessity to unregister a suspended
1228 * device created with a call to device_create() (devices cannot be
1229 * unregistered directly while suspended, since the PM core holds their
1230 * semaphores at that time).
1232 * It can only be called within the scope of a system sleep transition. In
1233 * practice this means it has to be directly or indirectly invoked either by
1234 * a suspend or resume method, or by the PM core (e.g. via
1235 * disable_nonboot_cpus() or enable_nonboot_cpus()).
1237 void destroy_suspended_device(struct class *class, dev_t devt)
1241 dev = find_device(class, devt);
1243 device_pm_schedule_removal(dev);
1245 EXPORT_SYMBOL_GPL(destroy_suspended_device);
1246 #endif /* CONFIG_PM_SLEEP */
1249 * device_rename - renames a device
1250 * @dev: the pointer to the struct device to be renamed
1251 * @new_name: the new name of the device
1253 int device_rename(struct device *dev, char *new_name)
1255 char *old_class_name = NULL;
1256 char *new_class_name = NULL;
1257 char *old_device_name = NULL;
1260 dev = get_device(dev);
1264 pr_debug("DEVICE: renaming '%s' to '%s'\n", dev->bus_id, new_name);
1266 #ifdef CONFIG_SYSFS_DEPRECATED
1267 if ((dev->class) && (dev->parent))
1268 old_class_name = make_class_name(dev->class->name, &dev->kobj);
1271 old_device_name = kmalloc(BUS_ID_SIZE, GFP_KERNEL);
1272 if (!old_device_name) {
1276 strlcpy(old_device_name, dev->bus_id, BUS_ID_SIZE);
1277 strlcpy(dev->bus_id, new_name, BUS_ID_SIZE);
1279 error = kobject_rename(&dev->kobj, new_name);
1281 strlcpy(dev->bus_id, old_device_name, BUS_ID_SIZE);
1285 #ifdef CONFIG_SYSFS_DEPRECATED
1286 if (old_class_name) {
1287 new_class_name = make_class_name(dev->class->name, &dev->kobj);
1288 if (new_class_name) {
1289 error = sysfs_create_link(&dev->parent->kobj,
1290 &dev->kobj, new_class_name);
1293 sysfs_remove_link(&dev->parent->kobj, old_class_name);
1298 sysfs_remove_link(&dev->class->subsys.kobj, old_device_name);
1299 error = sysfs_create_link(&dev->class->subsys.kobj, &dev->kobj,
1302 dev_err(dev, "%s: sysfs_create_symlink failed (%d)\n",
1303 __FUNCTION__, error);
1311 kfree(new_class_name);
1312 kfree(old_class_name);
1313 kfree(old_device_name);
1317 EXPORT_SYMBOL_GPL(device_rename);
1319 static int device_move_class_links(struct device *dev,
1320 struct device *old_parent,
1321 struct device *new_parent)
1324 #ifdef CONFIG_SYSFS_DEPRECATED
1327 class_name = make_class_name(dev->class->name, &dev->kobj);
1333 sysfs_remove_link(&dev->kobj, "device");
1334 sysfs_remove_link(&old_parent->kobj, class_name);
1337 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1341 error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
1344 sysfs_remove_link(&dev->kobj, "device");
1353 sysfs_remove_link(&dev->kobj, "device");
1355 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1362 * device_move - moves a device to a new parent
1363 * @dev: the pointer to the struct device to be moved
1364 * @new_parent: the new parent of the device (can by NULL)
1366 int device_move(struct device *dev, struct device *new_parent)
1369 struct device *old_parent;
1370 struct kobject *new_parent_kobj;
1372 dev = get_device(dev);
1376 new_parent = get_device(new_parent);
1377 new_parent_kobj = get_device_parent (dev, new_parent);
1378 if (IS_ERR(new_parent_kobj)) {
1379 error = PTR_ERR(new_parent_kobj);
1380 put_device(new_parent);
1383 pr_debug("DEVICE: moving '%s' to '%s'\n", dev->bus_id,
1384 new_parent ? new_parent->bus_id : "<NULL>");
1385 error = kobject_move(&dev->kobj, new_parent_kobj);
1387 put_device(new_parent);
1390 old_parent = dev->parent;
1391 dev->parent = new_parent;
1393 klist_remove(&dev->knode_parent);
1395 klist_add_tail(&dev->knode_parent, &new_parent->klist_children);
1398 error = device_move_class_links(dev, old_parent, new_parent);
1400 /* We ignore errors on cleanup since we're hosed anyway... */
1401 device_move_class_links(dev, new_parent, old_parent);
1402 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1404 klist_remove(&dev->knode_parent);
1406 klist_add_tail(&dev->knode_parent,
1407 &old_parent->klist_children);
1409 put_device(new_parent);
1413 put_device(old_parent);
1419 EXPORT_SYMBOL_GPL(device_move);