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>
21 #include <asm/semaphore.h>
24 #include "power/power.h"
26 int (*platform_notify)(struct device * dev) = NULL;
27 int (*platform_notify_remove)(struct device * dev) = NULL;
30 * sysfs bindings for devices.
34 * dev_driver_string - Return a device's driver name, if at all possible
35 * @dev: struct device to get the name of
37 * Will return the device's driver's name if it is bound to a device. If
38 * the device is not bound to a device, it will return the name of the bus
39 * it is attached to. If it is not attached to a bus either, an empty
40 * string will be returned.
42 const char *dev_driver_string(struct device *dev)
44 return dev->driver ? dev->driver->name :
45 (dev->bus ? dev->bus->name : "");
47 EXPORT_SYMBOL_GPL(dev_driver_string);
49 #define to_dev(obj) container_of(obj, struct device, kobj)
50 #define to_dev_attr(_attr) container_of(_attr, struct device_attribute, attr)
53 dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
55 struct device_attribute * dev_attr = to_dev_attr(attr);
56 struct device * dev = to_dev(kobj);
60 ret = dev_attr->show(dev, dev_attr, buf);
65 dev_attr_store(struct kobject * kobj, struct attribute * attr,
66 const char * buf, size_t count)
68 struct device_attribute * dev_attr = to_dev_attr(attr);
69 struct device * dev = to_dev(kobj);
73 ret = dev_attr->store(dev, dev_attr, buf, count);
77 static struct sysfs_ops dev_sysfs_ops = {
78 .show = dev_attr_show,
79 .store = dev_attr_store,
84 * device_release - free device structure.
85 * @kobj: device's kobject.
87 * This is called once the reference count for the object
88 * reaches 0. We forward the call to the device's release
89 * method, which should handle actually freeing the structure.
91 static void device_release(struct kobject * kobj)
93 struct device * dev = to_dev(kobj);
97 else if (dev->class && dev->class->dev_release)
98 dev->class->dev_release(dev);
100 printk(KERN_ERR "Device '%s' does not have a release() function, "
101 "it is broken and must be fixed.\n",
107 static struct kobj_type ktype_device = {
108 .release = device_release,
109 .sysfs_ops = &dev_sysfs_ops,
113 static int dev_uevent_filter(struct kset *kset, struct kobject *kobj)
115 struct kobj_type *ktype = get_ktype(kobj);
117 if (ktype == &ktype_device) {
118 struct device *dev = to_dev(kobj);
127 static const char *dev_uevent_name(struct kset *kset, struct kobject *kobj)
129 struct device *dev = to_dev(kobj);
132 return dev->bus->name;
134 return dev->class->name;
138 static int dev_uevent(struct kset *kset, struct kobject *kobj, char **envp,
139 int num_envp, char *buffer, int buffer_size)
141 struct device *dev = to_dev(kobj);
146 /* add the major/minor if present */
147 if (MAJOR(dev->devt)) {
148 add_uevent_var(envp, num_envp, &i,
149 buffer, buffer_size, &length,
150 "MAJOR=%u", MAJOR(dev->devt));
151 add_uevent_var(envp, num_envp, &i,
152 buffer, buffer_size, &length,
153 "MINOR=%u", MINOR(dev->devt));
156 /* add bus name (same as SUBSYSTEM, deprecated) */
158 add_uevent_var(envp, num_envp, &i,
159 buffer, buffer_size, &length,
160 "PHYSDEVBUS=%s", dev->bus->name);
162 /* add driver name (PHYSDEV* values are deprecated)*/
164 add_uevent_var(envp, num_envp, &i,
165 buffer, buffer_size, &length,
166 "DRIVER=%s", dev->driver->name);
167 add_uevent_var(envp, num_envp, &i,
168 buffer, buffer_size, &length,
169 "PHYSDEVDRIVER=%s", dev->driver->name);
172 /* terminate, set to next free slot, shrink available space */
176 buffer = &buffer[length];
177 buffer_size -= length;
179 if (dev->bus && dev->bus->uevent) {
180 /* have the bus specific function add its stuff */
181 retval = dev->bus->uevent(dev, envp, num_envp, buffer, buffer_size);
183 pr_debug ("%s - uevent() returned %d\n",
184 __FUNCTION__, retval);
188 if (dev->class && dev->class->dev_uevent) {
189 /* have the class specific function add its stuff */
190 retval = dev->class->dev_uevent(dev, envp, num_envp, buffer, buffer_size);
192 pr_debug("%s - dev_uevent() returned %d\n",
193 __FUNCTION__, retval);
200 static struct kset_uevent_ops device_uevent_ops = {
201 .filter = dev_uevent_filter,
202 .name = dev_uevent_name,
203 .uevent = dev_uevent,
206 static ssize_t store_uevent(struct device *dev, struct device_attribute *attr,
207 const char *buf, size_t count)
209 kobject_uevent(&dev->kobj, KOBJ_ADD);
213 static int device_add_groups(struct device *dev)
219 for (i = 0; dev->groups[i]; i++) {
220 error = sysfs_create_group(&dev->kobj, dev->groups[i]);
223 sysfs_remove_group(&dev->kobj, dev->groups[i]);
232 static void device_remove_groups(struct device *dev)
236 for (i = 0; dev->groups[i]; i++) {
237 sysfs_remove_group(&dev->kobj, dev->groups[i]);
242 static int device_add_attrs(struct device *dev)
244 struct class *class = dev->class;
251 if (class->dev_attrs) {
252 for (i = 0; attr_name(class->dev_attrs[i]); i++) {
253 error = device_create_file(dev, &class->dev_attrs[i]);
260 device_remove_file(dev, &class->dev_attrs[i]);
264 static void device_remove_attrs(struct device *dev)
266 struct class *class = dev->class;
272 if (class->dev_attrs) {
273 for (i = 0; attr_name(class->dev_attrs[i]); i++)
274 device_remove_file(dev, &class->dev_attrs[i]);
279 static ssize_t show_dev(struct device *dev, struct device_attribute *attr,
282 return print_dev_t(buf, dev->devt);
286 * devices_subsys - structure to be registered with kobject core.
289 decl_subsys(devices, &ktype_device, &device_uevent_ops);
293 * device_create_file - create sysfs attribute file for device.
295 * @attr: device attribute descriptor.
298 int device_create_file(struct device * dev, struct device_attribute * attr)
301 if (get_device(dev)) {
302 error = sysfs_create_file(&dev->kobj, &attr->attr);
309 * device_remove_file - remove sysfs attribute file.
311 * @attr: device attribute descriptor.
314 void device_remove_file(struct device * dev, struct device_attribute * attr)
316 if (get_device(dev)) {
317 sysfs_remove_file(&dev->kobj, &attr->attr);
322 static void klist_children_get(struct klist_node *n)
324 struct device *dev = container_of(n, struct device, knode_parent);
329 static void klist_children_put(struct klist_node *n)
331 struct device *dev = container_of(n, struct device, knode_parent);
338 * device_initialize - init device structure.
341 * This prepares the device for use by other layers,
342 * including adding it to the device hierarchy.
343 * It is the first half of device_register(), if called by
344 * that, though it can also be called separately, so one
345 * may use @dev's fields (e.g. the refcount).
348 void device_initialize(struct device *dev)
350 kobj_set_kset_s(dev, devices_subsys);
351 kobject_init(&dev->kobj);
352 klist_init(&dev->klist_children, klist_children_get,
354 INIT_LIST_HEAD(&dev->dma_pools);
355 INIT_LIST_HEAD(&dev->node);
356 init_MUTEX(&dev->sem);
357 device_init_wakeup(dev, 0);
361 * device_add - add device to device hierarchy.
364 * This is part 2 of device_register(), though may be called
365 * separately _iff_ device_initialize() has been called separately.
367 * This adds it to the kobject hierarchy via kobject_add(), adds it
368 * to the global and sibling lists for the device, then
369 * adds it to the other relevant subsystems of the driver model.
371 int device_add(struct device *dev)
373 struct device *parent = NULL;
374 char *class_name = NULL;
377 dev = get_device(dev);
378 if (!dev || !strlen(dev->bus_id))
381 parent = get_device(dev->parent);
383 pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id);
385 /* first, register with generic layer. */
386 kobject_set_name(&dev->kobj, "%s", dev->bus_id);
388 dev->kobj.parent = &parent->kobj;
390 if ((error = kobject_add(&dev->kobj)))
393 dev->uevent_attr.attr.name = "uevent";
394 dev->uevent_attr.attr.mode = S_IWUSR;
396 dev->uevent_attr.attr.owner = dev->driver->owner;
397 dev->uevent_attr.store = store_uevent;
398 device_create_file(dev, &dev->uevent_attr);
400 if (MAJOR(dev->devt)) {
401 struct device_attribute *attr;
402 attr = kzalloc(sizeof(*attr), GFP_KERNEL);
407 attr->attr.name = "dev";
408 attr->attr.mode = S_IRUGO;
410 attr->attr.owner = dev->driver->owner;
411 attr->show = show_dev;
412 error = device_create_file(dev, attr);
418 dev->devt_attr = attr;
422 sysfs_create_link(&dev->kobj, &dev->class->subsys.kset.kobj,
424 sysfs_create_link(&dev->class->subsys.kset.kobj, &dev->kobj,
427 sysfs_create_link(&dev->kobj, &dev->parent->kobj, "device");
428 class_name = make_class_name(dev->class->name, &dev->kobj);
429 sysfs_create_link(&dev->parent->kobj, &dev->kobj, class_name);
433 if ((error = device_add_attrs(dev)))
435 if ((error = device_add_groups(dev)))
437 if ((error = device_pm_add(dev)))
439 if ((error = bus_add_device(dev)))
441 kobject_uevent(&dev->kobj, KOBJ_ADD);
442 bus_attach_device(dev);
444 klist_add_tail(&dev->knode_parent, &parent->klist_children);
447 /* tie the class to the device */
448 down(&dev->class->sem);
449 list_add_tail(&dev->node, &dev->class->devices);
450 up(&dev->class->sem);
453 /* notify platform of device entry */
455 platform_notify(dev);
461 device_pm_remove(dev);
463 device_remove_groups(dev);
465 device_remove_attrs(dev);
467 if (dev->devt_attr) {
468 device_remove_file(dev, dev->devt_attr);
469 kfree(dev->devt_attr);
472 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
473 kobject_del(&dev->kobj);
482 * device_register - register a device with the system.
483 * @dev: pointer to the device structure
485 * This happens in two clean steps - initialize the device
486 * and add it to the system. The two steps can be called
487 * separately, but this is the easiest and most common.
488 * I.e. you should only call the two helpers separately if
489 * have a clearly defined need to use and refcount the device
490 * before it is added to the hierarchy.
493 int device_register(struct device *dev)
495 device_initialize(dev);
496 return device_add(dev);
501 * get_device - increment reference count for device.
504 * This simply forwards the call to kobject_get(), though
505 * we do take care to provide for the case that we get a NULL
509 struct device * get_device(struct device * dev)
511 return dev ? to_dev(kobject_get(&dev->kobj)) : NULL;
516 * put_device - decrement reference count.
517 * @dev: device in question.
519 void put_device(struct device * dev)
522 kobject_put(&dev->kobj);
527 * device_del - delete device from system.
530 * This is the first part of the device unregistration
531 * sequence. This removes the device from the lists we control
532 * from here, has it removed from the other driver model
533 * subsystems it was added to in device_add(), and removes it
534 * from the kobject hierarchy.
536 * NOTE: this should be called manually _iff_ device_add() was
537 * also called manually.
540 void device_del(struct device * dev)
542 struct device * parent = dev->parent;
543 char *class_name = NULL;
546 klist_del(&dev->knode_parent);
548 device_remove_file(dev, dev->devt_attr);
550 sysfs_remove_link(&dev->kobj, "subsystem");
551 sysfs_remove_link(&dev->class->subsys.kset.kobj, dev->bus_id);
552 class_name = make_class_name(dev->class->name, &dev->kobj);
554 sysfs_remove_link(&dev->kobj, "device");
555 sysfs_remove_link(&dev->parent->kobj, class_name);
558 down(&dev->class->sem);
559 list_del_init(&dev->node);
560 up(&dev->class->sem);
562 device_remove_file(dev, &dev->uevent_attr);
563 device_remove_groups(dev);
564 device_remove_attrs(dev);
566 /* Notify the platform of the removal, in case they
567 * need to do anything...
569 if (platform_notify_remove)
570 platform_notify_remove(dev);
571 bus_remove_device(dev);
572 device_pm_remove(dev);
573 kobject_uevent(&dev->kobj, KOBJ_REMOVE);
574 kobject_del(&dev->kobj);
580 * device_unregister - unregister device from system.
581 * @dev: device going away.
583 * We do this in two parts, like we do device_register(). First,
584 * we remove it from all the subsystems with device_del(), then
585 * we decrement the reference count via put_device(). If that
586 * is the final reference count, the device will be cleaned up
587 * via device_release() above. Otherwise, the structure will
588 * stick around until the final reference to the device is dropped.
590 void device_unregister(struct device * dev)
592 pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id);
598 static struct device * next_device(struct klist_iter * i)
600 struct klist_node * n = klist_next(i);
601 return n ? container_of(n, struct device, knode_parent) : NULL;
605 * device_for_each_child - device child iterator.
606 * @parent: parent struct device.
607 * @data: data for the callback.
608 * @fn: function to be called for each device.
610 * Iterate over @parent's child devices, and call @fn for each,
613 * We check the return of @fn each time. If it returns anything
614 * other than 0, we break out and return that value.
616 int device_for_each_child(struct device * parent, void * data,
617 int (*fn)(struct device *, void *))
620 struct device * child;
623 klist_iter_init(&parent->klist_children, &i);
624 while ((child = next_device(&i)) && !error)
625 error = fn(child, data);
630 int __init devices_init(void)
632 return subsystem_register(&devices_subsys);
635 EXPORT_SYMBOL_GPL(device_for_each_child);
637 EXPORT_SYMBOL_GPL(device_initialize);
638 EXPORT_SYMBOL_GPL(device_add);
639 EXPORT_SYMBOL_GPL(device_register);
641 EXPORT_SYMBOL_GPL(device_del);
642 EXPORT_SYMBOL_GPL(device_unregister);
643 EXPORT_SYMBOL_GPL(get_device);
644 EXPORT_SYMBOL_GPL(put_device);
646 EXPORT_SYMBOL_GPL(device_create_file);
647 EXPORT_SYMBOL_GPL(device_remove_file);
650 static void device_create_release(struct device *dev)
652 pr_debug("%s called for %s\n", __FUNCTION__, dev->bus_id);
657 * device_create - creates a device and registers it with sysfs
658 * @class: pointer to the struct class that this device should be registered to
659 * @parent: pointer to the parent struct device of this new device, if any
660 * @devt: the dev_t for the char device to be added
661 * @fmt: string for the device's name
663 * This function can be used by char device classes. A struct device
664 * will be created in sysfs, registered to the specified class.
666 * A "dev" file will be created, showing the dev_t for the device, if
667 * the dev_t is not 0,0.
668 * If a pointer to a parent struct device is passed in, the newly created
669 * struct device will be a child of that device in sysfs.
670 * The pointer to the struct device will be returned from the call.
671 * Any further sysfs files that might be required can be created using this
674 * Note: the struct class passed to this function must have previously
675 * been created with a call to class_create().
677 struct device *device_create(struct class *class, struct device *parent,
678 dev_t devt, const char *fmt, ...)
681 struct device *dev = NULL;
682 int retval = -ENODEV;
684 if (class == NULL || IS_ERR(class))
687 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
695 dev->parent = parent;
696 dev->release = device_create_release;
699 vsnprintf(dev->bus_id, BUS_ID_SIZE, fmt, args);
701 retval = device_register(dev);
709 return ERR_PTR(retval);
711 EXPORT_SYMBOL_GPL(device_create);
714 * device_destroy - removes a device that was created with device_create()
715 * @class: pointer to the struct class that this device was registered with
716 * @devt: the dev_t of the device that was previously registered
718 * This call unregisters and cleans up a device that was created with a
719 * call to device_create().
721 void device_destroy(struct class *class, dev_t devt)
723 struct device *dev = NULL;
724 struct device *dev_tmp;
727 list_for_each_entry(dev_tmp, &class->devices, node) {
728 if (dev_tmp->devt == devt) {
736 device_unregister(dev);
738 EXPORT_SYMBOL_GPL(device_destroy);