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>
21 #include <linux/genhd.h>
22 #include <linux/kallsyms.h>
23 #include <linux/semaphore.h>
24 #include <linux/mutex.h>
25 #include <linux/async.h>
28 #include "power/power.h"
30 int (*platform_notify)(struct device *dev) = NULL;
31 int (*platform_notify_remove)(struct device *dev) = NULL;
32 static struct kobject *dev_kobj;
33 struct kobject *sysfs_dev_char_kobj;
34 struct kobject *sysfs_dev_block_kobj;
37 static inline int device_is_not_partition(struct device *dev)
39 return !(dev->type == &part_type);
42 static inline int device_is_not_partition(struct device *dev)
49 * dev_driver_string - Return a device's driver name, if at all possible
50 * @dev: struct device to get the name of
52 * Will return the device's driver's name if it is bound to a device. If
53 * the device is not bound to a device, it will return the name of the bus
54 * it is attached to. If it is not attached to a bus either, an empty
55 * string will be returned.
57 const char *dev_driver_string(const struct device *dev)
59 struct device_driver *drv;
61 /* dev->driver can change to NULL underneath us because of unbinding,
62 * so be careful about accessing it. dev->bus and dev->class should
63 * never change once they are set, so they don't need special care.
65 drv = ACCESS_ONCE(dev->driver);
66 return drv ? drv->name :
67 (dev->bus ? dev->bus->name :
68 (dev->class ? dev->class->name : ""));
70 EXPORT_SYMBOL(dev_driver_string);
72 #define to_dev(obj) container_of(obj, struct device, kobj)
73 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
75 static ssize_t dev_attr_show(struct kobject *kobj, struct attribute *attr,
78 struct device_attribute *dev_attr = to_dev_attr(attr);
79 struct device *dev = to_dev(kobj);
83 ret = dev_attr->show(dev, dev_attr, buf);
84 if (ret >= (ssize_t)PAGE_SIZE) {
85 print_symbol("dev_attr_show: %s returned bad count\n",
86 (unsigned long)dev_attr->show);
91 static ssize_t dev_attr_store(struct kobject *kobj, struct attribute *attr,
92 const char *buf, size_t count)
94 struct device_attribute *dev_attr = to_dev_attr(attr);
95 struct device *dev = to_dev(kobj);
99 ret = dev_attr->store(dev, dev_attr, buf, count);
103 static struct sysfs_ops dev_sysfs_ops = {
104 .show = dev_attr_show,
105 .store = dev_attr_store,
110 * device_release - free device structure.
111 * @kobj: device's kobject.
113 * This is called once the reference count for the object
114 * reaches 0. We forward the call to the device's release
115 * method, which should handle actually freeing the structure.
117 static void device_release(struct kobject *kobj)
119 struct device *dev = to_dev(kobj);
120 struct device_private *p = dev->p;
124 else if (dev->type && dev->type->release)
125 dev->type->release(dev);
126 else if (dev->class && dev->class->dev_release)
127 dev->class->dev_release(dev);
129 WARN(1, KERN_ERR "Device '%s' does not have a release() "
130 "function, it is broken and must be fixed.\n",
135 static struct kobj_type device_ktype = {
136 .release = device_release,
137 .sysfs_ops = &dev_sysfs_ops,
141 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
143 struct kobj_type *ktype = get_ktype(kobj);
145 if (ktype == &device_ktype) {
146 struct device *dev = to_dev(kobj);
155 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
157 struct device *dev = to_dev(kobj);
160 return dev->bus->name;
162 return dev->class->name;
166 static int dev_uevent(struct kset *kset, struct kobject *kobj,
167 struct kobj_uevent_env *env)
169 struct device *dev = to_dev(kobj);
172 /* add device node properties if present */
173 if (MAJOR(dev->devt)) {
178 add_uevent_var(env, "MAJOR=%u", MAJOR(dev->devt));
179 add_uevent_var(env, "MINOR=%u", MINOR(dev->devt));
180 name = device_get_devnode(dev, &mode, &tmp);
182 add_uevent_var(env, "DEVNAME=%s", name);
185 add_uevent_var(env, "DEVMODE=%#o", mode & 0777);
189 if (dev->type && dev->type->name)
190 add_uevent_var(env, "DEVTYPE=%s", dev->type->name);
193 add_uevent_var(env, "DRIVER=%s", dev->driver->name);
195 #ifdef CONFIG_SYSFS_DEPRECATED
197 struct device *parent = dev->parent;
199 /* find first bus device in parent chain */
200 while (parent && !parent->bus)
201 parent = parent->parent;
202 if (parent && parent->bus) {
205 path = kobject_get_path(&parent->kobj, GFP_KERNEL);
207 add_uevent_var(env, "PHYSDEVPATH=%s", path);
211 add_uevent_var(env, "PHYSDEVBUS=%s", parent->bus->name);
214 add_uevent_var(env, "PHYSDEVDRIVER=%s",
215 parent->driver->name);
217 } else if (dev->bus) {
218 add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
221 add_uevent_var(env, "PHYSDEVDRIVER=%s",
226 /* have the bus specific function add its stuff */
227 if (dev->bus && dev->bus->uevent) {
228 retval = dev->bus->uevent(dev, env);
230 pr_debug("device: '%s': %s: bus uevent() returned %d\n",
231 dev_name(dev), __func__, retval);
234 /* have the class specific function add its stuff */
235 if (dev->class && dev->class->dev_uevent) {
236 retval = dev->class->dev_uevent(dev, env);
238 pr_debug("device: '%s': %s: class uevent() "
239 "returned %d\n", dev_name(dev),
243 /* have the device type specific fuction add its stuff */
244 if (dev->type && dev->type->uevent) {
245 retval = dev->type->uevent(dev, env);
247 pr_debug("device: '%s': %s: dev_type uevent() "
248 "returned %d\n", dev_name(dev),
255 static struct kset_uevent_ops device_uevent_ops = {
256 .filter = dev_uevent_filter,
257 .name = dev_uevent_name,
258 .uevent = dev_uevent,
261 static ssize_t show_uevent(struct device *dev, struct device_attribute *attr,
264 struct kobject *top_kobj;
266 struct kobj_uevent_env *env = NULL;
271 /* search the kset, the device belongs to */
272 top_kobj = &dev->kobj;
273 while (!top_kobj->kset && top_kobj->parent)
274 top_kobj = top_kobj->parent;
278 kset = top_kobj->kset;
279 if (!kset->uevent_ops || !kset->uevent_ops->uevent)
283 if (kset->uevent_ops && kset->uevent_ops->filter)
284 if (!kset->uevent_ops->filter(kset, &dev->kobj))
287 env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
291 /* let the kset specific function add its keys */
292 retval = kset->uevent_ops->uevent(kset, &dev->kobj, env);
296 /* copy keys to file */
297 for (i = 0; i < env->envp_idx; i++)
298 count += sprintf(&buf[count], "%s\n", env->envp[i]);
304 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
305 const char *buf, size_t count)
307 enum kobject_action action;
309 if (kobject_action_type(buf, count, &action) == 0) {
310 kobject_uevent(&dev->kobj, action);
314 dev_err(dev, "uevent: unsupported action-string; this will "
315 "be ignored in a future kernel version\n");
316 kobject_uevent(&dev->kobj, KOBJ_ADD);
321 static struct device_attribute uevent_attr =
322 __ATTR(uevent, S_IRUGO | S_IWUSR, show_uevent, store_uevent);
324 static int device_add_attributes(struct device *dev,
325 struct device_attribute *attrs)
331 for (i = 0; attr_name(attrs[i]); i++) {
332 error = device_create_file(dev, &attrs[i]);
338 device_remove_file(dev, &attrs[i]);
343 static void device_remove_attributes(struct device *dev,
344 struct device_attribute *attrs)
349 for (i = 0; attr_name(attrs[i]); i++)
350 device_remove_file(dev, &attrs[i]);
353 static int device_add_groups(struct device *dev,
354 const struct attribute_group **groups)
360 for (i = 0; groups[i]; i++) {
361 error = sysfs_create_group(&dev->kobj, groups[i]);
364 sysfs_remove_group(&dev->kobj,
373 static void device_remove_groups(struct device *dev,
374 const struct attribute_group **groups)
379 for (i = 0; groups[i]; i++)
380 sysfs_remove_group(&dev->kobj, groups[i]);
383 static int device_add_attrs(struct device *dev)
385 struct class *class = dev->class;
386 struct device_type *type = dev->type;
390 error = device_add_attributes(dev, class->dev_attrs);
396 error = device_add_groups(dev, type->groups);
398 goto err_remove_class_attrs;
401 error = device_add_groups(dev, dev->groups);
403 goto err_remove_type_groups;
407 err_remove_type_groups:
409 device_remove_groups(dev, type->groups);
410 err_remove_class_attrs:
412 device_remove_attributes(dev, class->dev_attrs);
417 static void device_remove_attrs(struct device *dev)
419 struct class *class = dev->class;
420 struct device_type *type = dev->type;
422 device_remove_groups(dev, dev->groups);
425 device_remove_groups(dev, type->groups);
428 device_remove_attributes(dev, class->dev_attrs);
432 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
435 return print_dev_t(buf, dev->devt);
438 static struct device_attribute devt_attr =
439 __ATTR(dev, S_IRUGO, show_dev, NULL);
441 /* kset to create /sys/devices/ */
442 struct kset *devices_kset;
445 * device_create_file - create sysfs attribute file for device.
447 * @attr: device attribute descriptor.
449 int device_create_file(struct device *dev,
450 const struct device_attribute *attr)
454 error = sysfs_create_file(&dev->kobj, &attr->attr);
459 * device_remove_file - remove sysfs attribute file.
461 * @attr: device attribute descriptor.
463 void device_remove_file(struct device *dev,
464 const struct device_attribute *attr)
467 sysfs_remove_file(&dev->kobj, &attr->attr);
471 * device_create_bin_file - create sysfs binary attribute file for device.
473 * @attr: device binary attribute descriptor.
475 int device_create_bin_file(struct device *dev,
476 const struct bin_attribute *attr)
480 error = sysfs_create_bin_file(&dev->kobj, attr);
483 EXPORT_SYMBOL_GPL(device_create_bin_file);
486 * device_remove_bin_file - remove sysfs binary attribute file
488 * @attr: device binary attribute descriptor.
490 void device_remove_bin_file(struct device *dev,
491 const struct bin_attribute *attr)
494 sysfs_remove_bin_file(&dev->kobj, attr);
496 EXPORT_SYMBOL_GPL(device_remove_bin_file);
499 * device_schedule_callback_owner - helper to schedule a callback for a device
501 * @func: callback function to invoke later.
502 * @owner: module owning the callback routine
504 * Attribute methods must not unregister themselves or their parent device
505 * (which would amount to the same thing). Attempts to do so will deadlock,
506 * since unregistration is mutually exclusive with driver callbacks.
508 * Instead methods can call this routine, which will attempt to allocate
509 * and schedule a workqueue request to call back @func with @dev as its
510 * argument in the workqueue's process context. @dev will be pinned until
513 * This routine is usually called via the inline device_schedule_callback(),
514 * which automatically sets @owner to THIS_MODULE.
516 * Returns 0 if the request was submitted, -ENOMEM if storage could not
517 * be allocated, -ENODEV if a reference to @owner isn't available.
519 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
520 * underlying sysfs routine (since it is intended for use by attribute
521 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
523 int device_schedule_callback_owner(struct device *dev,
524 void (*func)(struct device *), struct module *owner)
526 return sysfs_schedule_callback(&dev->kobj,
527 (void (*)(void *)) func, dev, owner);
529 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
531 static void klist_children_get(struct klist_node *n)
533 struct device_private *p = to_device_private_parent(n);
534 struct device *dev = p->device;
539 static void klist_children_put(struct klist_node *n)
541 struct device_private *p = to_device_private_parent(n);
542 struct device *dev = p->device;
548 * device_initialize - init device structure.
551 * This prepares the device for use by other layers by initializing
553 * It is the first half of device_register(), if called by
554 * that function, though it can also be called separately, so one
555 * may use @dev's fields. In particular, get_device()/put_device()
556 * may be used for reference counting of @dev after calling this
559 * NOTE: Use put_device() to give up your reference instead of freeing
560 * @dev directly once you have called this function.
562 void device_initialize(struct device *dev)
564 dev->kobj.kset = devices_kset;
565 kobject_init(&dev->kobj, &device_ktype);
566 INIT_LIST_HEAD(&dev->dma_pools);
567 init_MUTEX(&dev->sem);
568 spin_lock_init(&dev->devres_lock);
569 INIT_LIST_HEAD(&dev->devres_head);
570 device_init_wakeup(dev, 0);
572 set_dev_node(dev, -1);
575 #ifdef CONFIG_SYSFS_DEPRECATED
576 static struct kobject *get_device_parent(struct device *dev,
577 struct device *parent)
579 /* class devices without a parent live in /sys/class/<classname>/ */
580 if (dev->class && (!parent || parent->class != dev->class))
581 return &dev->class->p->class_subsys.kobj;
582 /* all other devices keep their parent */
584 return &parent->kobj;
589 static inline void cleanup_device_parent(struct device *dev) {}
590 static inline void cleanup_glue_dir(struct device *dev,
591 struct kobject *glue_dir) {}
593 static struct kobject *virtual_device_parent(struct device *dev)
595 static struct kobject *virtual_dir = NULL;
598 virtual_dir = kobject_create_and_add("virtual",
599 &devices_kset->kobj);
604 static struct kobject *get_device_parent(struct device *dev,
605 struct device *parent)
610 static DEFINE_MUTEX(gdp_mutex);
611 struct kobject *kobj = NULL;
612 struct kobject *parent_kobj;
616 * If we have no parent, we live in "virtual".
617 * Class-devices with a non class-device as parent, live
618 * in a "glue" directory to prevent namespace collisions.
621 parent_kobj = virtual_device_parent(dev);
622 else if (parent->class)
623 return &parent->kobj;
625 parent_kobj = &parent->kobj;
627 mutex_lock(&gdp_mutex);
629 /* find our class-directory at the parent and reference it */
630 spin_lock(&dev->class->p->class_dirs.list_lock);
631 list_for_each_entry(k, &dev->class->p->class_dirs.list, entry)
632 if (k->parent == parent_kobj) {
633 kobj = kobject_get(k);
636 spin_unlock(&dev->class->p->class_dirs.list_lock);
638 mutex_unlock(&gdp_mutex);
642 /* or create a new class-directory at the parent device */
643 k = kobject_create();
645 mutex_unlock(&gdp_mutex);
648 k->kset = &dev->class->p->class_dirs;
649 retval = kobject_add(k, parent_kobj, "%s", dev->class->name);
651 mutex_unlock(&gdp_mutex);
655 /* do not emit an uevent for this simple "glue" directory */
656 mutex_unlock(&gdp_mutex);
661 return &parent->kobj;
665 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
667 /* see if we live in a "glue" directory */
668 if (!glue_dir || !dev->class ||
669 glue_dir->kset != &dev->class->p->class_dirs)
672 kobject_put(glue_dir);
675 static void cleanup_device_parent(struct device *dev)
677 cleanup_glue_dir(dev, dev->kobj.parent);
681 static void setup_parent(struct device *dev, struct device *parent)
683 struct kobject *kobj;
684 kobj = get_device_parent(dev, parent);
686 dev->kobj.parent = kobj;
689 static int device_add_class_symlinks(struct device *dev)
696 error = sysfs_create_link(&dev->kobj,
697 &dev->class->p->class_subsys.kobj,
702 #ifdef CONFIG_SYSFS_DEPRECATED
703 /* stacked class devices need a symlink in the class directory */
704 if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
705 device_is_not_partition(dev)) {
706 error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
707 &dev->kobj, dev_name(dev));
712 if (dev->parent && device_is_not_partition(dev)) {
713 struct device *parent = dev->parent;
717 * stacked class devices have the 'device' link
718 * pointing to the bus device instead of the parent
720 while (parent->class && !parent->bus && parent->parent)
721 parent = parent->parent;
723 error = sysfs_create_link(&dev->kobj,
729 class_name = make_class_name(dev->class->name,
732 error = sysfs_create_link(&dev->parent->kobj,
733 &dev->kobj, class_name);
741 if (dev->parent && device_is_not_partition(dev))
742 sysfs_remove_link(&dev->kobj, "device");
744 if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
745 device_is_not_partition(dev))
746 sysfs_remove_link(&dev->class->p->class_subsys.kobj,
749 /* link in the class directory pointing to the device */
750 error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
751 &dev->kobj, dev_name(dev));
755 if (dev->parent && device_is_not_partition(dev)) {
756 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
764 sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
768 sysfs_remove_link(&dev->kobj, "subsystem");
773 static void device_remove_class_symlinks(struct device *dev)
778 #ifdef CONFIG_SYSFS_DEPRECATED
779 if (dev->parent && device_is_not_partition(dev)) {
782 class_name = make_class_name(dev->class->name, &dev->kobj);
784 sysfs_remove_link(&dev->parent->kobj, class_name);
787 sysfs_remove_link(&dev->kobj, "device");
790 if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
791 device_is_not_partition(dev))
792 sysfs_remove_link(&dev->class->p->class_subsys.kobj,
795 if (dev->parent && device_is_not_partition(dev))
796 sysfs_remove_link(&dev->kobj, "device");
798 sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
801 sysfs_remove_link(&dev->kobj, "subsystem");
805 * dev_set_name - set a device name
807 * @fmt: format string for the device's name
809 int dev_set_name(struct device *dev, const char *fmt, ...)
814 va_start(vargs, fmt);
815 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
819 EXPORT_SYMBOL_GPL(dev_set_name);
822 * device_to_dev_kobj - select a /sys/dev/ directory for the device
825 * By default we select char/ for new entries. Setting class->dev_obj
826 * to NULL prevents an entry from being created. class->dev_kobj must
827 * be set (or cleared) before any devices are registered to the class
828 * otherwise device_create_sys_dev_entry() and
829 * device_remove_sys_dev_entry() will disagree about the the presence
832 static struct kobject *device_to_dev_kobj(struct device *dev)
834 struct kobject *kobj;
837 kobj = dev->class->dev_kobj;
839 kobj = sysfs_dev_char_kobj;
844 static int device_create_sys_dev_entry(struct device *dev)
846 struct kobject *kobj = device_to_dev_kobj(dev);
851 format_dev_t(devt_str, dev->devt);
852 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
858 static void device_remove_sys_dev_entry(struct device *dev)
860 struct kobject *kobj = device_to_dev_kobj(dev);
864 format_dev_t(devt_str, dev->devt);
865 sysfs_remove_link(kobj, devt_str);
869 int device_private_init(struct device *dev)
871 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
874 dev->p->device = dev;
875 klist_init(&dev->p->klist_children, klist_children_get,
881 * device_add - add device to device hierarchy.
884 * This is part 2 of device_register(), though may be called
885 * separately _iff_ device_initialize() has been called separately.
887 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
888 * to the global and sibling lists for the device, then
889 * adds it to the other relevant subsystems of the driver model.
891 * NOTE: _Never_ directly free @dev after calling this function, even
892 * if it returned an error! Always use put_device() to give up your
895 int device_add(struct device *dev)
897 struct device *parent = NULL;
898 struct class_interface *class_intf;
901 dev = get_device(dev);
906 error = device_private_init(dev);
912 * for statically allocated devices, which should all be converted
913 * some day, we need to initialize the name. We prevent reading back
914 * the name, and force the use of dev_name()
916 if (dev->init_name) {
917 dev_set_name(dev, "%s", dev->init_name);
918 dev->init_name = NULL;
921 if (!dev_name(dev)) {
926 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
928 parent = get_device(dev->parent);
929 setup_parent(dev, parent);
931 /* use parent numa_node */
933 set_dev_node(dev, dev_to_node(parent));
935 /* first, register with generic layer. */
936 /* we require the name to be set before, and pass NULL */
937 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
941 /* notify platform of device entry */
943 platform_notify(dev);
945 error = device_create_file(dev, &uevent_attr);
949 if (MAJOR(dev->devt)) {
950 error = device_create_file(dev, &devt_attr);
952 goto ueventattrError;
954 error = device_create_sys_dev_entry(dev);
958 devtmpfs_create_node(dev);
961 error = device_add_class_symlinks(dev);
964 error = device_add_attrs(dev);
967 error = bus_add_device(dev);
970 error = dpm_sysfs_add(dev);
975 /* Notify clients of device addition. This call must come
976 * after dpm_sysf_add() and before kobject_uevent().
979 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
980 BUS_NOTIFY_ADD_DEVICE, dev);
982 kobject_uevent(&dev->kobj, KOBJ_ADD);
983 bus_probe_device(dev);
985 klist_add_tail(&dev->p->knode_parent,
986 &parent->p->klist_children);
989 mutex_lock(&dev->class->p->class_mutex);
990 /* tie the class to the device */
991 klist_add_tail(&dev->knode_class,
992 &dev->class->p->class_devices);
994 /* notify any interfaces that the device is here */
995 list_for_each_entry(class_intf,
996 &dev->class->p->class_interfaces, node)
997 if (class_intf->add_dev)
998 class_intf->add_dev(dev, class_intf);
999 mutex_unlock(&dev->class->p->class_mutex);
1005 bus_remove_device(dev);
1007 device_remove_attrs(dev);
1009 device_remove_class_symlinks(dev);
1011 if (MAJOR(dev->devt))
1012 devtmpfs_delete_node(dev);
1013 if (MAJOR(dev->devt))
1014 device_remove_sys_dev_entry(dev);
1016 if (MAJOR(dev->devt))
1017 device_remove_file(dev, &devt_attr);
1019 device_remove_file(dev, &uevent_attr);
1021 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1022 kobject_del(&dev->kobj);
1024 cleanup_device_parent(dev);
1034 * device_register - register a device with the system.
1035 * @dev: pointer to the device structure
1037 * This happens in two clean steps - initialize the device
1038 * and add it to the system. The two steps can be called
1039 * separately, but this is the easiest and most common.
1040 * I.e. you should only call the two helpers separately if
1041 * have a clearly defined need to use and refcount the device
1042 * before it is added to the hierarchy.
1044 * NOTE: _Never_ directly free @dev after calling this function, even
1045 * if it returned an error! Always use put_device() to give up the
1046 * reference initialized in this function instead.
1048 int device_register(struct device *dev)
1050 device_initialize(dev);
1051 return device_add(dev);
1055 * get_device - increment reference count for device.
1058 * This simply forwards the call to kobject_get(), though
1059 * we do take care to provide for the case that we get a NULL
1060 * pointer passed in.
1062 struct device *get_device(struct device *dev)
1064 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
1068 * put_device - decrement reference count.
1069 * @dev: device in question.
1071 void put_device(struct device *dev)
1073 /* might_sleep(); */
1075 kobject_put(&dev->kobj);
1079 * device_del - delete device from system.
1082 * This is the first part of the device unregistration
1083 * sequence. This removes the device from the lists we control
1084 * from here, has it removed from the other driver model
1085 * subsystems it was added to in device_add(), and removes it
1086 * from the kobject hierarchy.
1088 * NOTE: this should be called manually _iff_ device_add() was
1089 * also called manually.
1091 void device_del(struct device *dev)
1093 struct device *parent = dev->parent;
1094 struct class_interface *class_intf;
1096 /* Notify clients of device removal. This call must come
1097 * before dpm_sysfs_remove().
1100 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1101 BUS_NOTIFY_DEL_DEVICE, dev);
1102 device_pm_remove(dev);
1103 dpm_sysfs_remove(dev);
1105 klist_del(&dev->p->knode_parent);
1106 if (MAJOR(dev->devt)) {
1107 devtmpfs_delete_node(dev);
1108 device_remove_sys_dev_entry(dev);
1109 device_remove_file(dev, &devt_attr);
1112 device_remove_class_symlinks(dev);
1114 mutex_lock(&dev->class->p->class_mutex);
1115 /* notify any interfaces that the device is now gone */
1116 list_for_each_entry(class_intf,
1117 &dev->class->p->class_interfaces, node)
1118 if (class_intf->remove_dev)
1119 class_intf->remove_dev(dev, class_intf);
1120 /* remove the device from the class list */
1121 klist_del(&dev->knode_class);
1122 mutex_unlock(&dev->class->p->class_mutex);
1124 device_remove_file(dev, &uevent_attr);
1125 device_remove_attrs(dev);
1126 bus_remove_device(dev);
1129 * Some platform devices are driven without driver attached
1130 * and managed resources may have been acquired. Make sure
1131 * all resources are released.
1133 devres_release_all(dev);
1135 /* Notify the platform of the removal, in case they
1136 * need to do anything...
1138 if (platform_notify_remove)
1139 platform_notify_remove(dev);
1140 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1141 cleanup_device_parent(dev);
1142 kobject_del(&dev->kobj);
1147 * device_unregister - unregister device from system.
1148 * @dev: device going away.
1150 * We do this in two parts, like we do device_register(). First,
1151 * we remove it from all the subsystems with device_del(), then
1152 * we decrement the reference count via put_device(). If that
1153 * is the final reference count, the device will be cleaned up
1154 * via device_release() above. Otherwise, the structure will
1155 * stick around until the final reference to the device is dropped.
1157 void device_unregister(struct device *dev)
1159 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1164 static struct device *next_device(struct klist_iter *i)
1166 struct klist_node *n = klist_next(i);
1167 struct device *dev = NULL;
1168 struct device_private *p;
1171 p = to_device_private_parent(n);
1178 * device_get_devnode - path of device node file
1180 * @mode: returned file access mode
1181 * @tmp: possibly allocated string
1183 * Return the relative path of a possible device node.
1184 * Non-default names may need to allocate a memory to compose
1185 * a name. This memory is returned in tmp and needs to be
1186 * freed by the caller.
1188 const char *device_get_devnode(struct device *dev,
1189 mode_t *mode, const char **tmp)
1195 /* the device type may provide a specific name */
1196 if (dev->type && dev->type->devnode)
1197 *tmp = dev->type->devnode(dev, mode);
1201 /* the class may provide a specific name */
1202 if (dev->class && dev->class->devnode)
1203 *tmp = dev->class->devnode(dev, mode);
1207 /* return name without allocation, tmp == NULL */
1208 if (strchr(dev_name(dev), '!') == NULL)
1209 return dev_name(dev);
1211 /* replace '!' in the name with '/' */
1212 *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1215 while ((s = strchr(*tmp, '!')))
1221 * device_for_each_child - device child iterator.
1222 * @parent: parent struct device.
1223 * @data: data for the callback.
1224 * @fn: function to be called for each device.
1226 * Iterate over @parent's child devices, and call @fn for each,
1229 * We check the return of @fn each time. If it returns anything
1230 * other than 0, we break out and return that value.
1232 int device_for_each_child(struct device *parent, void *data,
1233 int (*fn)(struct device *dev, void *data))
1235 struct klist_iter i;
1236 struct device *child;
1242 klist_iter_init(&parent->p->klist_children, &i);
1243 while ((child = next_device(&i)) && !error)
1244 error = fn(child, data);
1245 klist_iter_exit(&i);
1250 * device_find_child - device iterator for locating a particular device.
1251 * @parent: parent struct device
1252 * @data: Data to pass to match function
1253 * @match: Callback function to check device
1255 * This is similar to the device_for_each_child() function above, but it
1256 * returns a reference to a device that is 'found' for later use, as
1257 * determined by the @match callback.
1259 * The callback should return 0 if the device doesn't match and non-zero
1260 * if it does. If the callback returns non-zero and a reference to the
1261 * current device can be obtained, this function will return to the caller
1262 * and not iterate over any more devices.
1264 struct device *device_find_child(struct device *parent, void *data,
1265 int (*match)(struct device *dev, void *data))
1267 struct klist_iter i;
1268 struct device *child;
1273 klist_iter_init(&parent->p->klist_children, &i);
1274 while ((child = next_device(&i)))
1275 if (match(child, data) && get_device(child))
1277 klist_iter_exit(&i);
1281 int __init devices_init(void)
1283 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1286 dev_kobj = kobject_create_and_add("dev", NULL);
1289 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1290 if (!sysfs_dev_block_kobj)
1291 goto block_kobj_err;
1292 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1293 if (!sysfs_dev_char_kobj)
1299 kobject_put(sysfs_dev_block_kobj);
1301 kobject_put(dev_kobj);
1303 kset_unregister(devices_kset);
1307 EXPORT_SYMBOL_GPL(device_for_each_child);
1308 EXPORT_SYMBOL_GPL(device_find_child);
1310 EXPORT_SYMBOL_GPL(device_initialize);
1311 EXPORT_SYMBOL_GPL(device_add);
1312 EXPORT_SYMBOL_GPL(device_register);
1314 EXPORT_SYMBOL_GPL(device_del);
1315 EXPORT_SYMBOL_GPL(device_unregister);
1316 EXPORT_SYMBOL_GPL(get_device);
1317 EXPORT_SYMBOL_GPL(put_device);
1319 EXPORT_SYMBOL_GPL(device_create_file);
1320 EXPORT_SYMBOL_GPL(device_remove_file);
1325 struct module *owner;
1328 #define to_root_device(dev) container_of(dev, struct root_device, dev)
1330 static void root_device_release(struct device *dev)
1332 kfree(to_root_device(dev));
1336 * __root_device_register - allocate and register a root device
1337 * @name: root device name
1338 * @owner: owner module of the root device, usually THIS_MODULE
1340 * This function allocates a root device and registers it
1341 * using device_register(). In order to free the returned
1342 * device, use root_device_unregister().
1344 * Root devices are dummy devices which allow other devices
1345 * to be grouped under /sys/devices. Use this function to
1346 * allocate a root device and then use it as the parent of
1347 * any device which should appear under /sys/devices/{name}
1349 * The /sys/devices/{name} directory will also contain a
1350 * 'module' symlink which points to the @owner directory
1353 * Note: You probably want to use root_device_register().
1355 struct device *__root_device_register(const char *name, struct module *owner)
1357 struct root_device *root;
1360 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1362 return ERR_PTR(err);
1364 err = dev_set_name(&root->dev, "%s", name);
1367 return ERR_PTR(err);
1370 root->dev.release = root_device_release;
1372 err = device_register(&root->dev);
1374 put_device(&root->dev);
1375 return ERR_PTR(err);
1378 #ifdef CONFIG_MODULE /* gotta find a "cleaner" way to do this */
1380 struct module_kobject *mk = &owner->mkobj;
1382 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1384 device_unregister(&root->dev);
1385 return ERR_PTR(err);
1387 root->owner = owner;
1393 EXPORT_SYMBOL_GPL(__root_device_register);
1396 * root_device_unregister - unregister and free a root device
1397 * @dev: device going away
1399 * This function unregisters and cleans up a device that was created by
1400 * root_device_register().
1402 void root_device_unregister(struct device *dev)
1404 struct root_device *root = to_root_device(dev);
1407 sysfs_remove_link(&root->dev.kobj, "module");
1409 device_unregister(dev);
1411 EXPORT_SYMBOL_GPL(root_device_unregister);
1414 static void device_create_release(struct device *dev)
1416 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1421 * device_create_vargs - creates a device and registers it with sysfs
1422 * @class: pointer to the struct class that this device should be registered to
1423 * @parent: pointer to the parent struct device of this new device, if any
1424 * @devt: the dev_t for the char device to be added
1425 * @drvdata: the data to be added to the device for callbacks
1426 * @fmt: string for the device's name
1427 * @args: va_list for the device's name
1429 * This function can be used by char device classes. A struct device
1430 * will be created in sysfs, registered to the specified class.
1432 * A "dev" file will be created, showing the dev_t for the device, if
1433 * the dev_t is not 0,0.
1434 * If a pointer to a parent struct device is passed in, the newly created
1435 * struct device will be a child of that device in sysfs.
1436 * The pointer to the struct device will be returned from the call.
1437 * Any further sysfs files that might be required can be created using this
1440 * Note: the struct class passed to this function must have previously
1441 * been created with a call to class_create().
1443 struct device *device_create_vargs(struct class *class, struct device *parent,
1444 dev_t devt, void *drvdata, const char *fmt,
1447 struct device *dev = NULL;
1448 int retval = -ENODEV;
1450 if (class == NULL || IS_ERR(class))
1453 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1461 dev->parent = parent;
1462 dev->release = device_create_release;
1463 dev_set_drvdata(dev, drvdata);
1465 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1469 retval = device_register(dev);
1477 return ERR_PTR(retval);
1479 EXPORT_SYMBOL_GPL(device_create_vargs);
1482 * device_create - creates a device and registers it with sysfs
1483 * @class: pointer to the struct class that this device should be registered to
1484 * @parent: pointer to the parent struct device of this new device, if any
1485 * @devt: the dev_t for the char device to be added
1486 * @drvdata: the data to be added to the device for callbacks
1487 * @fmt: string for the device's name
1489 * This function can be used by char device classes. A struct device
1490 * will be created in sysfs, registered to the specified class.
1492 * A "dev" file will be created, showing the dev_t for the device, if
1493 * the dev_t is not 0,0.
1494 * If a pointer to a parent struct device is passed in, the newly created
1495 * struct device will be a child of that device in sysfs.
1496 * The pointer to the struct device will be returned from the call.
1497 * Any further sysfs files that might be required can be created using this
1500 * Note: the struct class passed to this function must have previously
1501 * been created with a call to class_create().
1503 struct device *device_create(struct class *class, struct device *parent,
1504 dev_t devt, void *drvdata, const char *fmt, ...)
1509 va_start(vargs, fmt);
1510 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1514 EXPORT_SYMBOL_GPL(device_create);
1516 static int __match_devt(struct device *dev, void *data)
1520 return dev->devt == *devt;
1524 * device_destroy - removes a device that was created with device_create()
1525 * @class: pointer to the struct class that this device was registered with
1526 * @devt: the dev_t of the device that was previously registered
1528 * This call unregisters and cleans up a device that was created with a
1529 * call to device_create().
1531 void device_destroy(struct class *class, dev_t devt)
1535 dev = class_find_device(class, NULL, &devt, __match_devt);
1538 device_unregister(dev);
1541 EXPORT_SYMBOL_GPL(device_destroy);
1544 * device_rename - renames a device
1545 * @dev: the pointer to the struct device to be renamed
1546 * @new_name: the new name of the device
1548 * It is the responsibility of the caller to provide mutual
1549 * exclusion between two different calls of device_rename
1550 * on the same device to ensure that new_name is valid and
1551 * won't conflict with other devices.
1553 int device_rename(struct device *dev, char *new_name)
1555 char *old_class_name = NULL;
1556 char *new_class_name = NULL;
1557 char *old_device_name = NULL;
1560 dev = get_device(dev);
1564 pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1565 __func__, new_name);
1567 #ifdef CONFIG_SYSFS_DEPRECATED
1568 if ((dev->class) && (dev->parent))
1569 old_class_name = make_class_name(dev->class->name, &dev->kobj);
1572 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1573 if (!old_device_name) {
1578 error = kobject_rename(&dev->kobj, new_name);
1582 #ifdef CONFIG_SYSFS_DEPRECATED
1583 if (old_class_name) {
1584 new_class_name = make_class_name(dev->class->name, &dev->kobj);
1585 if (new_class_name) {
1586 error = sysfs_create_link_nowarn(&dev->parent->kobj,
1591 sysfs_remove_link(&dev->parent->kobj, old_class_name);
1596 error = sysfs_create_link_nowarn(&dev->class->p->class_subsys.kobj,
1597 &dev->kobj, dev_name(dev));
1600 sysfs_remove_link(&dev->class->p->class_subsys.kobj,
1608 kfree(new_class_name);
1609 kfree(old_class_name);
1610 kfree(old_device_name);
1614 EXPORT_SYMBOL_GPL(device_rename);
1616 static int device_move_class_links(struct device *dev,
1617 struct device *old_parent,
1618 struct device *new_parent)
1621 #ifdef CONFIG_SYSFS_DEPRECATED
1624 class_name = make_class_name(dev->class->name, &dev->kobj);
1630 sysfs_remove_link(&dev->kobj, "device");
1631 sysfs_remove_link(&old_parent->kobj, class_name);
1634 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1638 error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
1641 sysfs_remove_link(&dev->kobj, "device");
1649 sysfs_remove_link(&dev->kobj, "device");
1651 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1658 * device_move - moves a device to a new parent
1659 * @dev: the pointer to the struct device to be moved
1660 * @new_parent: the new parent of the device (can by NULL)
1661 * @dpm_order: how to reorder the dpm_list
1663 int device_move(struct device *dev, struct device *new_parent,
1664 enum dpm_order dpm_order)
1667 struct device *old_parent;
1668 struct kobject *new_parent_kobj;
1670 dev = get_device(dev);
1675 new_parent = get_device(new_parent);
1676 new_parent_kobj = get_device_parent(dev, new_parent);
1678 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1679 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1680 error = kobject_move(&dev->kobj, new_parent_kobj);
1682 cleanup_glue_dir(dev, new_parent_kobj);
1683 put_device(new_parent);
1686 old_parent = dev->parent;
1687 dev->parent = new_parent;
1689 klist_remove(&dev->p->knode_parent);
1691 klist_add_tail(&dev->p->knode_parent,
1692 &new_parent->p->klist_children);
1693 set_dev_node(dev, dev_to_node(new_parent));
1698 error = device_move_class_links(dev, old_parent, new_parent);
1700 /* We ignore errors on cleanup since we're hosed anyway... */
1701 device_move_class_links(dev, new_parent, old_parent);
1702 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1704 klist_remove(&dev->p->knode_parent);
1705 dev->parent = old_parent;
1707 klist_add_tail(&dev->p->knode_parent,
1708 &old_parent->p->klist_children);
1709 set_dev_node(dev, dev_to_node(old_parent));
1712 cleanup_glue_dir(dev, new_parent_kobj);
1713 put_device(new_parent);
1716 switch (dpm_order) {
1717 case DPM_ORDER_NONE:
1719 case DPM_ORDER_DEV_AFTER_PARENT:
1720 device_pm_move_after(dev, new_parent);
1722 case DPM_ORDER_PARENT_BEFORE_DEV:
1723 device_pm_move_before(new_parent, dev);
1725 case DPM_ORDER_DEV_LAST:
1726 device_pm_move_last(dev);
1730 put_device(old_parent);
1736 EXPORT_SYMBOL_GPL(device_move);
1739 * device_shutdown - call ->shutdown() on each device to shutdown.
1741 void device_shutdown(void)
1743 struct device *dev, *devn;
1745 list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list,
1747 if (dev->bus && dev->bus->shutdown) {
1748 dev_dbg(dev, "shutdown\n");
1749 dev->bus->shutdown(dev);
1750 } else if (dev->driver && dev->driver->shutdown) {
1751 dev_dbg(dev, "shutdown\n");
1752 dev->driver->shutdown(dev);
1755 async_synchronize_full();