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, struct device_attribute *attr)
453 error = sysfs_create_file(&dev->kobj, &attr->attr);
458 * device_remove_file - remove sysfs attribute file.
460 * @attr: device attribute descriptor.
462 void device_remove_file(struct device *dev, struct device_attribute *attr)
465 sysfs_remove_file(&dev->kobj, &attr->attr);
469 * device_create_bin_file - create sysfs binary attribute file for device.
471 * @attr: device binary attribute descriptor.
473 int device_create_bin_file(struct device *dev, struct bin_attribute *attr)
477 error = sysfs_create_bin_file(&dev->kobj, attr);
480 EXPORT_SYMBOL_GPL(device_create_bin_file);
483 * device_remove_bin_file - remove sysfs binary attribute file
485 * @attr: device binary attribute descriptor.
487 void device_remove_bin_file(struct device *dev, struct bin_attribute *attr)
490 sysfs_remove_bin_file(&dev->kobj, attr);
492 EXPORT_SYMBOL_GPL(device_remove_bin_file);
495 * device_schedule_callback_owner - helper to schedule a callback for a device
497 * @func: callback function to invoke later.
498 * @owner: module owning the callback routine
500 * Attribute methods must not unregister themselves or their parent device
501 * (which would amount to the same thing). Attempts to do so will deadlock,
502 * since unregistration is mutually exclusive with driver callbacks.
504 * Instead methods can call this routine, which will attempt to allocate
505 * and schedule a workqueue request to call back @func with @dev as its
506 * argument in the workqueue's process context. @dev will be pinned until
509 * This routine is usually called via the inline device_schedule_callback(),
510 * which automatically sets @owner to THIS_MODULE.
512 * Returns 0 if the request was submitted, -ENOMEM if storage could not
513 * be allocated, -ENODEV if a reference to @owner isn't available.
515 * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
516 * underlying sysfs routine (since it is intended for use by attribute
517 * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
519 int device_schedule_callback_owner(struct device *dev,
520 void (*func)(struct device *), struct module *owner)
522 return sysfs_schedule_callback(&dev->kobj,
523 (void (*)(void *)) func, dev, owner);
525 EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
527 static void klist_children_get(struct klist_node *n)
529 struct device_private *p = to_device_private_parent(n);
530 struct device *dev = p->device;
535 static void klist_children_put(struct klist_node *n)
537 struct device_private *p = to_device_private_parent(n);
538 struct device *dev = p->device;
544 * device_initialize - init device structure.
547 * This prepares the device for use by other layers by initializing
549 * It is the first half of device_register(), if called by
550 * that function, though it can also be called separately, so one
551 * may use @dev's fields. In particular, get_device()/put_device()
552 * may be used for reference counting of @dev after calling this
555 * NOTE: Use put_device() to give up your reference instead of freeing
556 * @dev directly once you have called this function.
558 void device_initialize(struct device *dev)
560 dev->kobj.kset = devices_kset;
561 kobject_init(&dev->kobj, &device_ktype);
562 INIT_LIST_HEAD(&dev->dma_pools);
563 init_MUTEX(&dev->sem);
564 spin_lock_init(&dev->devres_lock);
565 INIT_LIST_HEAD(&dev->devres_head);
566 device_init_wakeup(dev, 0);
568 set_dev_node(dev, -1);
571 #ifdef CONFIG_SYSFS_DEPRECATED
572 static struct kobject *get_device_parent(struct device *dev,
573 struct device *parent)
575 /* class devices without a parent live in /sys/class/<classname>/ */
576 if (dev->class && (!parent || parent->class != dev->class))
577 return &dev->class->p->class_subsys.kobj;
578 /* all other devices keep their parent */
580 return &parent->kobj;
585 static inline void cleanup_device_parent(struct device *dev) {}
586 static inline void cleanup_glue_dir(struct device *dev,
587 struct kobject *glue_dir) {}
589 static struct kobject *virtual_device_parent(struct device *dev)
591 static struct kobject *virtual_dir = NULL;
594 virtual_dir = kobject_create_and_add("virtual",
595 &devices_kset->kobj);
600 static struct kobject *get_device_parent(struct device *dev,
601 struct device *parent)
606 struct kobject *kobj = NULL;
607 struct kobject *parent_kobj;
611 * If we have no parent, we live in "virtual".
612 * Class-devices with a non class-device as parent, live
613 * in a "glue" directory to prevent namespace collisions.
616 parent_kobj = virtual_device_parent(dev);
617 else if (parent->class)
618 return &parent->kobj;
620 parent_kobj = &parent->kobj;
622 /* find our class-directory at the parent and reference it */
623 spin_lock(&dev->class->p->class_dirs.list_lock);
624 list_for_each_entry(k, &dev->class->p->class_dirs.list, entry)
625 if (k->parent == parent_kobj) {
626 kobj = kobject_get(k);
629 spin_unlock(&dev->class->p->class_dirs.list_lock);
633 /* or create a new class-directory at the parent device */
634 k = kobject_create();
637 k->kset = &dev->class->p->class_dirs;
638 retval = kobject_add(k, parent_kobj, "%s", dev->class->name);
643 /* do not emit an uevent for this simple "glue" directory */
648 return &parent->kobj;
652 static void cleanup_glue_dir(struct device *dev, struct kobject *glue_dir)
654 /* see if we live in a "glue" directory */
655 if (!glue_dir || !dev->class ||
656 glue_dir->kset != &dev->class->p->class_dirs)
659 kobject_put(glue_dir);
662 static void cleanup_device_parent(struct device *dev)
664 cleanup_glue_dir(dev, dev->kobj.parent);
668 static void setup_parent(struct device *dev, struct device *parent)
670 struct kobject *kobj;
671 kobj = get_device_parent(dev, parent);
673 dev->kobj.parent = kobj;
676 static int device_add_class_symlinks(struct device *dev)
683 error = sysfs_create_link(&dev->kobj,
684 &dev->class->p->class_subsys.kobj,
689 #ifdef CONFIG_SYSFS_DEPRECATED
690 /* stacked class devices need a symlink in the class directory */
691 if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
692 device_is_not_partition(dev)) {
693 error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
694 &dev->kobj, dev_name(dev));
699 if (dev->parent && device_is_not_partition(dev)) {
700 struct device *parent = dev->parent;
704 * stacked class devices have the 'device' link
705 * pointing to the bus device instead of the parent
707 while (parent->class && !parent->bus && parent->parent)
708 parent = parent->parent;
710 error = sysfs_create_link(&dev->kobj,
716 class_name = make_class_name(dev->class->name,
719 error = sysfs_create_link(&dev->parent->kobj,
720 &dev->kobj, class_name);
728 if (dev->parent && device_is_not_partition(dev))
729 sysfs_remove_link(&dev->kobj, "device");
731 if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
732 device_is_not_partition(dev))
733 sysfs_remove_link(&dev->class->p->class_subsys.kobj,
736 /* link in the class directory pointing to the device */
737 error = sysfs_create_link(&dev->class->p->class_subsys.kobj,
738 &dev->kobj, dev_name(dev));
742 if (dev->parent && device_is_not_partition(dev)) {
743 error = sysfs_create_link(&dev->kobj, &dev->parent->kobj,
751 sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
755 sysfs_remove_link(&dev->kobj, "subsystem");
760 static void device_remove_class_symlinks(struct device *dev)
765 #ifdef CONFIG_SYSFS_DEPRECATED
766 if (dev->parent && device_is_not_partition(dev)) {
769 class_name = make_class_name(dev->class->name, &dev->kobj);
771 sysfs_remove_link(&dev->parent->kobj, class_name);
774 sysfs_remove_link(&dev->kobj, "device");
777 if (dev->kobj.parent != &dev->class->p->class_subsys.kobj &&
778 device_is_not_partition(dev))
779 sysfs_remove_link(&dev->class->p->class_subsys.kobj,
782 if (dev->parent && device_is_not_partition(dev))
783 sysfs_remove_link(&dev->kobj, "device");
785 sysfs_remove_link(&dev->class->p->class_subsys.kobj, dev_name(dev));
788 sysfs_remove_link(&dev->kobj, "subsystem");
792 * dev_set_name - set a device name
794 * @fmt: format string for the device's name
796 int dev_set_name(struct device *dev, const char *fmt, ...)
801 va_start(vargs, fmt);
802 err = kobject_set_name_vargs(&dev->kobj, fmt, vargs);
806 EXPORT_SYMBOL_GPL(dev_set_name);
809 * device_to_dev_kobj - select a /sys/dev/ directory for the device
812 * By default we select char/ for new entries. Setting class->dev_obj
813 * to NULL prevents an entry from being created. class->dev_kobj must
814 * be set (or cleared) before any devices are registered to the class
815 * otherwise device_create_sys_dev_entry() and
816 * device_remove_sys_dev_entry() will disagree about the the presence
819 static struct kobject *device_to_dev_kobj(struct device *dev)
821 struct kobject *kobj;
824 kobj = dev->class->dev_kobj;
826 kobj = sysfs_dev_char_kobj;
831 static int device_create_sys_dev_entry(struct device *dev)
833 struct kobject *kobj = device_to_dev_kobj(dev);
838 format_dev_t(devt_str, dev->devt);
839 error = sysfs_create_link(kobj, &dev->kobj, devt_str);
845 static void device_remove_sys_dev_entry(struct device *dev)
847 struct kobject *kobj = device_to_dev_kobj(dev);
851 format_dev_t(devt_str, dev->devt);
852 sysfs_remove_link(kobj, devt_str);
856 int device_private_init(struct device *dev)
858 dev->p = kzalloc(sizeof(*dev->p), GFP_KERNEL);
861 dev->p->device = dev;
862 klist_init(&dev->p->klist_children, klist_children_get,
868 * device_add - add device to device hierarchy.
871 * This is part 2 of device_register(), though may be called
872 * separately _iff_ device_initialize() has been called separately.
874 * This adds @dev to the kobject hierarchy via kobject_add(), adds it
875 * to the global and sibling lists for the device, then
876 * adds it to the other relevant subsystems of the driver model.
878 * NOTE: _Never_ directly free @dev after calling this function, even
879 * if it returned an error! Always use put_device() to give up your
882 int device_add(struct device *dev)
884 struct device *parent = NULL;
885 struct class_interface *class_intf;
888 dev = get_device(dev);
893 error = device_private_init(dev);
899 * for statically allocated devices, which should all be converted
900 * some day, we need to initialize the name. We prevent reading back
901 * the name, and force the use of dev_name()
903 if (dev->init_name) {
904 dev_set_name(dev, "%s", dev->init_name);
905 dev->init_name = NULL;
911 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
913 parent = get_device(dev->parent);
914 setup_parent(dev, parent);
916 /* use parent numa_node */
918 set_dev_node(dev, dev_to_node(parent));
920 /* first, register with generic layer. */
921 /* we require the name to be set before, and pass NULL */
922 error = kobject_add(&dev->kobj, dev->kobj.parent, NULL);
926 /* notify platform of device entry */
928 platform_notify(dev);
930 error = device_create_file(dev, &uevent_attr);
934 if (MAJOR(dev->devt)) {
935 error = device_create_file(dev, &devt_attr);
937 goto ueventattrError;
939 error = device_create_sys_dev_entry(dev);
943 devtmpfs_create_node(dev);
946 error = device_add_class_symlinks(dev);
949 error = device_add_attrs(dev);
952 error = bus_add_device(dev);
955 error = dpm_sysfs_add(dev);
960 /* Notify clients of device addition. This call must come
961 * after dpm_sysf_add() and before kobject_uevent().
964 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
965 BUS_NOTIFY_ADD_DEVICE, dev);
967 kobject_uevent(&dev->kobj, KOBJ_ADD);
968 bus_probe_device(dev);
970 klist_add_tail(&dev->p->knode_parent,
971 &parent->p->klist_children);
974 mutex_lock(&dev->class->p->class_mutex);
975 /* tie the class to the device */
976 klist_add_tail(&dev->knode_class,
977 &dev->class->p->class_devices);
979 /* notify any interfaces that the device is here */
980 list_for_each_entry(class_intf,
981 &dev->class->p->class_interfaces, node)
982 if (class_intf->add_dev)
983 class_intf->add_dev(dev, class_intf);
984 mutex_unlock(&dev->class->p->class_mutex);
990 bus_remove_device(dev);
992 device_remove_attrs(dev);
994 device_remove_class_symlinks(dev);
996 if (MAJOR(dev->devt))
997 devtmpfs_delete_node(dev);
998 if (MAJOR(dev->devt))
999 device_remove_sys_dev_entry(dev);
1001 if (MAJOR(dev->devt))
1002 device_remove_file(dev, &devt_attr);
1004 device_remove_file(dev, &uevent_attr);
1006 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1007 kobject_del(&dev->kobj);
1009 cleanup_device_parent(dev);
1019 * device_register - register a device with the system.
1020 * @dev: pointer to the device structure
1022 * This happens in two clean steps - initialize the device
1023 * and add it to the system. The two steps can be called
1024 * separately, but this is the easiest and most common.
1025 * I.e. you should only call the two helpers separately if
1026 * have a clearly defined need to use and refcount the device
1027 * before it is added to the hierarchy.
1029 * NOTE: _Never_ directly free @dev after calling this function, even
1030 * if it returned an error! Always use put_device() to give up the
1031 * reference initialized in this function instead.
1033 int device_register(struct device *dev)
1035 device_initialize(dev);
1036 return device_add(dev);
1040 * get_device - increment reference count for device.
1043 * This simply forwards the call to kobject_get(), though
1044 * we do take care to provide for the case that we get a NULL
1045 * pointer passed in.
1047 struct device *get_device(struct device *dev)
1049 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
1053 * put_device - decrement reference count.
1054 * @dev: device in question.
1056 void put_device(struct device *dev)
1058 /* might_sleep(); */
1060 kobject_put(&dev->kobj);
1064 * device_del - delete device from system.
1067 * This is the first part of the device unregistration
1068 * sequence. This removes the device from the lists we control
1069 * from here, has it removed from the other driver model
1070 * subsystems it was added to in device_add(), and removes it
1071 * from the kobject hierarchy.
1073 * NOTE: this should be called manually _iff_ device_add() was
1074 * also called manually.
1076 void device_del(struct device *dev)
1078 struct device *parent = dev->parent;
1079 struct class_interface *class_intf;
1081 /* Notify clients of device removal. This call must come
1082 * before dpm_sysfs_remove().
1085 blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
1086 BUS_NOTIFY_DEL_DEVICE, dev);
1087 device_pm_remove(dev);
1088 dpm_sysfs_remove(dev);
1090 klist_del(&dev->p->knode_parent);
1091 if (MAJOR(dev->devt)) {
1092 devtmpfs_delete_node(dev);
1093 device_remove_sys_dev_entry(dev);
1094 device_remove_file(dev, &devt_attr);
1097 device_remove_class_symlinks(dev);
1099 mutex_lock(&dev->class->p->class_mutex);
1100 /* notify any interfaces that the device is now gone */
1101 list_for_each_entry(class_intf,
1102 &dev->class->p->class_interfaces, node)
1103 if (class_intf->remove_dev)
1104 class_intf->remove_dev(dev, class_intf);
1105 /* remove the device from the class list */
1106 klist_del(&dev->knode_class);
1107 mutex_unlock(&dev->class->p->class_mutex);
1109 device_remove_file(dev, &uevent_attr);
1110 device_remove_attrs(dev);
1111 bus_remove_device(dev);
1114 * Some platform devices are driven without driver attached
1115 * and managed resources may have been acquired. Make sure
1116 * all resources are released.
1118 devres_release_all(dev);
1120 /* Notify the platform of the removal, in case they
1121 * need to do anything...
1123 if (platform_notify_remove)
1124 platform_notify_remove(dev);
1125 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
1126 cleanup_device_parent(dev);
1127 kobject_del(&dev->kobj);
1132 * device_unregister - unregister device from system.
1133 * @dev: device going away.
1135 * We do this in two parts, like we do device_register(). First,
1136 * we remove it from all the subsystems with device_del(), then
1137 * we decrement the reference count via put_device(). If that
1138 * is the final reference count, the device will be cleaned up
1139 * via device_release() above. Otherwise, the structure will
1140 * stick around until the final reference to the device is dropped.
1142 void device_unregister(struct device *dev)
1144 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1149 static struct device *next_device(struct klist_iter *i)
1151 struct klist_node *n = klist_next(i);
1152 struct device *dev = NULL;
1153 struct device_private *p;
1156 p = to_device_private_parent(n);
1163 * device_get_devnode - path of device node file
1165 * @mode: returned file access mode
1166 * @tmp: possibly allocated string
1168 * Return the relative path of a possible device node.
1169 * Non-default names may need to allocate a memory to compose
1170 * a name. This memory is returned in tmp and needs to be
1171 * freed by the caller.
1173 const char *device_get_devnode(struct device *dev,
1174 mode_t *mode, const char **tmp)
1180 /* the device type may provide a specific name */
1181 if (dev->type && dev->type->devnode)
1182 *tmp = dev->type->devnode(dev, mode);
1186 /* the class may provide a specific name */
1187 if (dev->class && dev->class->devnode)
1188 *tmp = dev->class->devnode(dev, mode);
1192 /* return name without allocation, tmp == NULL */
1193 if (strchr(dev_name(dev), '!') == NULL)
1194 return dev_name(dev);
1196 /* replace '!' in the name with '/' */
1197 *tmp = kstrdup(dev_name(dev), GFP_KERNEL);
1200 while ((s = strchr(*tmp, '!')))
1206 * device_for_each_child - device child iterator.
1207 * @parent: parent struct device.
1208 * @data: data for the callback.
1209 * @fn: function to be called for each device.
1211 * Iterate over @parent's child devices, and call @fn for each,
1214 * We check the return of @fn each time. If it returns anything
1215 * other than 0, we break out and return that value.
1217 int device_for_each_child(struct device *parent, void *data,
1218 int (*fn)(struct device *dev, void *data))
1220 struct klist_iter i;
1221 struct device *child;
1227 klist_iter_init(&parent->p->klist_children, &i);
1228 while ((child = next_device(&i)) && !error)
1229 error = fn(child, data);
1230 klist_iter_exit(&i);
1235 * device_find_child - device iterator for locating a particular device.
1236 * @parent: parent struct device
1237 * @data: Data to pass to match function
1238 * @match: Callback function to check device
1240 * This is similar to the device_for_each_child() function above, but it
1241 * returns a reference to a device that is 'found' for later use, as
1242 * determined by the @match callback.
1244 * The callback should return 0 if the device doesn't match and non-zero
1245 * if it does. If the callback returns non-zero and a reference to the
1246 * current device can be obtained, this function will return to the caller
1247 * and not iterate over any more devices.
1249 struct device *device_find_child(struct device *parent, void *data,
1250 int (*match)(struct device *dev, void *data))
1252 struct klist_iter i;
1253 struct device *child;
1258 klist_iter_init(&parent->p->klist_children, &i);
1259 while ((child = next_device(&i)))
1260 if (match(child, data) && get_device(child))
1262 klist_iter_exit(&i);
1266 int __init devices_init(void)
1268 devices_kset = kset_create_and_add("devices", &device_uevent_ops, NULL);
1271 dev_kobj = kobject_create_and_add("dev", NULL);
1274 sysfs_dev_block_kobj = kobject_create_and_add("block", dev_kobj);
1275 if (!sysfs_dev_block_kobj)
1276 goto block_kobj_err;
1277 sysfs_dev_char_kobj = kobject_create_and_add("char", dev_kobj);
1278 if (!sysfs_dev_char_kobj)
1284 kobject_put(sysfs_dev_block_kobj);
1286 kobject_put(dev_kobj);
1288 kset_unregister(devices_kset);
1292 EXPORT_SYMBOL_GPL(device_for_each_child);
1293 EXPORT_SYMBOL_GPL(device_find_child);
1295 EXPORT_SYMBOL_GPL(device_initialize);
1296 EXPORT_SYMBOL_GPL(device_add);
1297 EXPORT_SYMBOL_GPL(device_register);
1299 EXPORT_SYMBOL_GPL(device_del);
1300 EXPORT_SYMBOL_GPL(device_unregister);
1301 EXPORT_SYMBOL_GPL(get_device);
1302 EXPORT_SYMBOL_GPL(put_device);
1304 EXPORT_SYMBOL_GPL(device_create_file);
1305 EXPORT_SYMBOL_GPL(device_remove_file);
1310 struct module *owner;
1313 #define to_root_device(dev) container_of(dev, struct root_device, dev)
1315 static void root_device_release(struct device *dev)
1317 kfree(to_root_device(dev));
1321 * __root_device_register - allocate and register a root device
1322 * @name: root device name
1323 * @owner: owner module of the root device, usually THIS_MODULE
1325 * This function allocates a root device and registers it
1326 * using device_register(). In order to free the returned
1327 * device, use root_device_unregister().
1329 * Root devices are dummy devices which allow other devices
1330 * to be grouped under /sys/devices. Use this function to
1331 * allocate a root device and then use it as the parent of
1332 * any device which should appear under /sys/devices/{name}
1334 * The /sys/devices/{name} directory will also contain a
1335 * 'module' symlink which points to the @owner directory
1338 * Note: You probably want to use root_device_register().
1340 struct device *__root_device_register(const char *name, struct module *owner)
1342 struct root_device *root;
1345 root = kzalloc(sizeof(struct root_device), GFP_KERNEL);
1347 return ERR_PTR(err);
1349 err = dev_set_name(&root->dev, "%s", name);
1352 return ERR_PTR(err);
1355 root->dev.release = root_device_release;
1357 err = device_register(&root->dev);
1359 put_device(&root->dev);
1360 return ERR_PTR(err);
1363 #ifdef CONFIG_MODULE /* gotta find a "cleaner" way to do this */
1365 struct module_kobject *mk = &owner->mkobj;
1367 err = sysfs_create_link(&root->dev.kobj, &mk->kobj, "module");
1369 device_unregister(&root->dev);
1370 return ERR_PTR(err);
1372 root->owner = owner;
1378 EXPORT_SYMBOL_GPL(__root_device_register);
1381 * root_device_unregister - unregister and free a root device
1382 * @dev: device going away
1384 * This function unregisters and cleans up a device that was created by
1385 * root_device_register().
1387 void root_device_unregister(struct device *dev)
1389 struct root_device *root = to_root_device(dev);
1392 sysfs_remove_link(&root->dev.kobj, "module");
1394 device_unregister(dev);
1396 EXPORT_SYMBOL_GPL(root_device_unregister);
1399 static void device_create_release(struct device *dev)
1401 pr_debug("device: '%s': %s\n", dev_name(dev), __func__);
1406 * device_create_vargs - creates a device and registers it with sysfs
1407 * @class: pointer to the struct class that this device should be registered to
1408 * @parent: pointer to the parent struct device of this new device, if any
1409 * @devt: the dev_t for the char device to be added
1410 * @drvdata: the data to be added to the device for callbacks
1411 * @fmt: string for the device's name
1412 * @args: va_list for the device's name
1414 * This function can be used by char device classes. A struct device
1415 * will be created in sysfs, registered to the specified class.
1417 * A "dev" file will be created, showing the dev_t for the device, if
1418 * the dev_t is not 0,0.
1419 * If a pointer to a parent struct device is passed in, the newly created
1420 * struct device will be a child of that device in sysfs.
1421 * The pointer to the struct device will be returned from the call.
1422 * Any further sysfs files that might be required can be created using this
1425 * Note: the struct class passed to this function must have previously
1426 * been created with a call to class_create().
1428 struct device *device_create_vargs(struct class *class, struct device *parent,
1429 dev_t devt, void *drvdata, const char *fmt,
1432 struct device *dev = NULL;
1433 int retval = -ENODEV;
1435 if (class == NULL || IS_ERR(class))
1438 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
1446 dev->parent = parent;
1447 dev->release = device_create_release;
1448 dev_set_drvdata(dev, drvdata);
1450 retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
1454 retval = device_register(dev);
1462 return ERR_PTR(retval);
1464 EXPORT_SYMBOL_GPL(device_create_vargs);
1467 * device_create - creates a device and registers it with sysfs
1468 * @class: pointer to the struct class that this device should be registered to
1469 * @parent: pointer to the parent struct device of this new device, if any
1470 * @devt: the dev_t for the char device to be added
1471 * @drvdata: the data to be added to the device for callbacks
1472 * @fmt: string for the device's name
1474 * This function can be used by char device classes. A struct device
1475 * will be created in sysfs, registered to the specified class.
1477 * A "dev" file will be created, showing the dev_t for the device, if
1478 * the dev_t is not 0,0.
1479 * If a pointer to a parent struct device is passed in, the newly created
1480 * struct device will be a child of that device in sysfs.
1481 * The pointer to the struct device will be returned from the call.
1482 * Any further sysfs files that might be required can be created using this
1485 * Note: the struct class passed to this function must have previously
1486 * been created with a call to class_create().
1488 struct device *device_create(struct class *class, struct device *parent,
1489 dev_t devt, void *drvdata, const char *fmt, ...)
1494 va_start(vargs, fmt);
1495 dev = device_create_vargs(class, parent, devt, drvdata, fmt, vargs);
1499 EXPORT_SYMBOL_GPL(device_create);
1501 static int __match_devt(struct device *dev, void *data)
1505 return dev->devt == *devt;
1509 * device_destroy - removes a device that was created with device_create()
1510 * @class: pointer to the struct class that this device was registered with
1511 * @devt: the dev_t of the device that was previously registered
1513 * This call unregisters and cleans up a device that was created with a
1514 * call to device_create().
1516 void device_destroy(struct class *class, dev_t devt)
1520 dev = class_find_device(class, NULL, &devt, __match_devt);
1523 device_unregister(dev);
1526 EXPORT_SYMBOL_GPL(device_destroy);
1529 * device_rename - renames a device
1530 * @dev: the pointer to the struct device to be renamed
1531 * @new_name: the new name of the device
1533 * It is the responsibility of the caller to provide mutual
1534 * exclusion between two different calls of device_rename
1535 * on the same device to ensure that new_name is valid and
1536 * won't conflict with other devices.
1538 int device_rename(struct device *dev, char *new_name)
1540 char *old_class_name = NULL;
1541 char *new_class_name = NULL;
1542 char *old_device_name = NULL;
1545 dev = get_device(dev);
1549 pr_debug("device: '%s': %s: renaming to '%s'\n", dev_name(dev),
1550 __func__, new_name);
1552 #ifdef CONFIG_SYSFS_DEPRECATED
1553 if ((dev->class) && (dev->parent))
1554 old_class_name = make_class_name(dev->class->name, &dev->kobj);
1557 old_device_name = kstrdup(dev_name(dev), GFP_KERNEL);
1558 if (!old_device_name) {
1563 error = kobject_rename(&dev->kobj, new_name);
1567 #ifdef CONFIG_SYSFS_DEPRECATED
1568 if (old_class_name) {
1569 new_class_name = make_class_name(dev->class->name, &dev->kobj);
1570 if (new_class_name) {
1571 error = sysfs_create_link_nowarn(&dev->parent->kobj,
1576 sysfs_remove_link(&dev->parent->kobj, old_class_name);
1581 error = sysfs_create_link_nowarn(&dev->class->p->class_subsys.kobj,
1582 &dev->kobj, dev_name(dev));
1585 sysfs_remove_link(&dev->class->p->class_subsys.kobj,
1593 kfree(new_class_name);
1594 kfree(old_class_name);
1595 kfree(old_device_name);
1599 EXPORT_SYMBOL_GPL(device_rename);
1601 static int device_move_class_links(struct device *dev,
1602 struct device *old_parent,
1603 struct device *new_parent)
1606 #ifdef CONFIG_SYSFS_DEPRECATED
1609 class_name = make_class_name(dev->class->name, &dev->kobj);
1615 sysfs_remove_link(&dev->kobj, "device");
1616 sysfs_remove_link(&old_parent->kobj, class_name);
1619 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1623 error = sysfs_create_link(&new_parent->kobj, &dev->kobj,
1626 sysfs_remove_link(&dev->kobj, "device");
1634 sysfs_remove_link(&dev->kobj, "device");
1636 error = sysfs_create_link(&dev->kobj, &new_parent->kobj,
1643 * device_move - moves a device to a new parent
1644 * @dev: the pointer to the struct device to be moved
1645 * @new_parent: the new parent of the device (can by NULL)
1646 * @dpm_order: how to reorder the dpm_list
1648 int device_move(struct device *dev, struct device *new_parent,
1649 enum dpm_order dpm_order)
1652 struct device *old_parent;
1653 struct kobject *new_parent_kobj;
1655 dev = get_device(dev);
1660 new_parent = get_device(new_parent);
1661 new_parent_kobj = get_device_parent(dev, new_parent);
1663 pr_debug("device: '%s': %s: moving to '%s'\n", dev_name(dev),
1664 __func__, new_parent ? dev_name(new_parent) : "<NULL>");
1665 error = kobject_move(&dev->kobj, new_parent_kobj);
1667 cleanup_glue_dir(dev, new_parent_kobj);
1668 put_device(new_parent);
1671 old_parent = dev->parent;
1672 dev->parent = new_parent;
1674 klist_remove(&dev->p->knode_parent);
1676 klist_add_tail(&dev->p->knode_parent,
1677 &new_parent->p->klist_children);
1678 set_dev_node(dev, dev_to_node(new_parent));
1683 error = device_move_class_links(dev, old_parent, new_parent);
1685 /* We ignore errors on cleanup since we're hosed anyway... */
1686 device_move_class_links(dev, new_parent, old_parent);
1687 if (!kobject_move(&dev->kobj, &old_parent->kobj)) {
1689 klist_remove(&dev->p->knode_parent);
1690 dev->parent = old_parent;
1692 klist_add_tail(&dev->p->knode_parent,
1693 &old_parent->p->klist_children);
1694 set_dev_node(dev, dev_to_node(old_parent));
1697 cleanup_glue_dir(dev, new_parent_kobj);
1698 put_device(new_parent);
1701 switch (dpm_order) {
1702 case DPM_ORDER_NONE:
1704 case DPM_ORDER_DEV_AFTER_PARENT:
1705 device_pm_move_after(dev, new_parent);
1707 case DPM_ORDER_PARENT_BEFORE_DEV:
1708 device_pm_move_before(new_parent, dev);
1710 case DPM_ORDER_DEV_LAST:
1711 device_pm_move_last(dev);
1715 put_device(old_parent);
1721 EXPORT_SYMBOL_GPL(device_move);
1724 * device_shutdown - call ->shutdown() on each device to shutdown.
1726 void device_shutdown(void)
1728 struct device *dev, *devn;
1730 list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list,
1732 if (dev->bus && dev->bus->shutdown) {
1733 dev_dbg(dev, "shutdown\n");
1734 dev->bus->shutdown(dev);
1735 } else if (dev->driver && dev->driver->shutdown) {
1736 dev_dbg(dev, "shutdown\n");
1737 dev->driver->shutdown(dev);
1740 async_synchronize_full();