drivers/base/sys.c - kernel/msm-4.19 - Gitiles

 /*
  * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
  *
  * Copyright (c) 2002-3 Patrick Mochel
  *               2002-3 Open Source Development Lab
  *
  * This file is released under the GPLv2
  *
  * This exports a 'system' bus type.
  * By default, a 'sys' bus gets added to the root of the system. There will
  * always be core system devices. Devices can use sysdev_register() to
  * add themselves as children of the system bus.
  */

 #include <linux/config.h>
 #include <linux/sysdev.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/pm.h>

 extern struct subsystem devices_subsys;

 #define to_sysdev(k) container_of(k, struct sys_device, kobj)
 #define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)


 static ssize_t
 sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
 {
 	struct sys_device * sysdev = to_sysdev(kobj);
 	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);

 	if (sysdev_attr->show)
 		return sysdev_attr->show(sysdev, buffer);
 	return -EIO;
 }


 static ssize_t
 sysdev_store(struct kobject * kobj, struct attribute * attr,
 	     const char * buffer, size_t count)
 {
 	struct sys_device * sysdev = to_sysdev(kobj);
 	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);

 	if (sysdev_attr->store)
 		return sysdev_attr->store(sysdev, buffer, count);
 	return -EIO;
 }

 static struct sysfs_ops sysfs_ops = {
 	.show	= sysdev_show,
 	.store	= sysdev_store,
 };

 static struct kobj_type ktype_sysdev = {
 	.sysfs_ops	= &sysfs_ops,
 };


 int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
 {
 	return sysfs_create_file(&s->kobj, &a->attr);
 }


 void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
 {
 	sysfs_remove_file(&s->kobj, &a->attr);
 }

 EXPORT_SYMBOL_GPL(sysdev_create_file);
 EXPORT_SYMBOL_GPL(sysdev_remove_file);

 /*
  * declare system_subsys
  */
 static decl_subsys(system, &ktype_sysdev, NULL);

 int sysdev_class_register(struct sysdev_class * cls)
 {
 	pr_debug("Registering sysdev class '%s'\n",
 		 kobject_name(&cls->kset.kobj));
 	INIT_LIST_HEAD(&cls->drivers);
 	cls->kset.subsys = &system_subsys;
 	kset_set_kset_s(cls, system_subsys);
 	return kset_register(&cls->kset);
 }

 void sysdev_class_unregister(struct sysdev_class * cls)
 {
 	pr_debug("Unregistering sysdev class '%s'\n",
 		 kobject_name(&cls->kset.kobj));
 	kset_unregister(&cls->kset);
 }

 EXPORT_SYMBOL_GPL(sysdev_class_register);
 EXPORT_SYMBOL_GPL(sysdev_class_unregister);


 static LIST_HEAD(sysdev_drivers);
 static DECLARE_MUTEX(sysdev_drivers_lock);

 /**
  *	sysdev_driver_register - Register auxillary driver
  * 	@cls:	Device class driver belongs to.
  *	@drv:	Driver.
  *
  *	If @cls is valid, then @drv is inserted into @cls->drivers to be
  *	called on each operation on devices of that class. The refcount
  *	of @cls is incremented.
  *	Otherwise, @drv is inserted into sysdev_drivers, and called for
  *	each device.
  */

 int sysdev_driver_register(struct sysdev_class * cls,
 			   struct sysdev_driver * drv)
 {
 	down(&sysdev_drivers_lock);
 	if (cls && kset_get(&cls->kset)) {
 		list_add_tail(&drv->entry, &cls->drivers);

 		/* If devices of this class already exist, tell the driver */
 		if (drv->add) {
 			struct sys_device *dev;
 			list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 				drv->add(dev);
 		}
 	} else
 		list_add_tail(&drv->entry, &sysdev_drivers);
 	up(&sysdev_drivers_lock);
 	return 0;
 }


 /**
  *	sysdev_driver_unregister - Remove an auxillary driver.
  *	@cls:	Class driver belongs to.
  *	@drv:	Driver.
  */
 void sysdev_driver_unregister(struct sysdev_class * cls,
 			      struct sysdev_driver * drv)
 {
 	down(&sysdev_drivers_lock);
 	list_del_init(&drv->entry);
 	if (cls) {
 		if (drv->remove) {
 			struct sys_device *dev;
 			list_for_each_entry(dev, &cls->kset.list, kobj.entry)
 				drv->remove(dev);
 		}
 		kset_put(&cls->kset);
 	}
 	up(&sysdev_drivers_lock);
 }

 EXPORT_SYMBOL_GPL(sysdev_driver_register);
 EXPORT_SYMBOL_GPL(sysdev_driver_unregister);


 /**
  *	sysdev_register - add a system device to the tree
  *	@sysdev:	device in question
  *
  */
 int sysdev_register(struct sys_device * sysdev)
 {
 	int error;
 	struct sysdev_class * cls = sysdev->cls;

 	if (!cls)
 		return -EINVAL;

 	/* Make sure the kset is set */
 	sysdev->kobj.kset = &cls->kset;

 	/* But make sure we point to the right type for sysfs translation */
 	sysdev->kobj.ktype = &ktype_sysdev;
 	error = kobject_set_name(&sysdev->kobj, "%s%d",
 			 kobject_name(&cls->kset.kobj), sysdev->id);
 	if (error)
 		return error;

 	pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));

 	/* Register the object */
 	error = kobject_register(&sysdev->kobj);

 	if (!error) {
 		struct sysdev_driver * drv;

 		down(&sysdev_drivers_lock);
 		/* Generic notification is implicit, because it's that
 		 * code that should have called us.
 		 */

 		/* Notify global drivers */
 		list_for_each_entry(drv, &sysdev_drivers, entry) {
 			if (drv->add)
 				drv->add(sysdev);
 		}

 		/* Notify class auxillary drivers */
 		list_for_each_entry(drv, &cls->drivers, entry) {
 			if (drv->add)
 				drv->add(sysdev);
 		}
 		up(&sysdev_drivers_lock);
 	}
 	return error;
 }

 void sysdev_unregister(struct sys_device * sysdev)
 {
 	struct sysdev_driver * drv;

 	down(&sysdev_drivers_lock);
 	list_for_each_entry(drv, &sysdev_drivers, entry) {
 		if (drv->remove)
 			drv->remove(sysdev);
 	}

 	list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
 		if (drv->remove)
 			drv->remove(sysdev);
 	}
 	up(&sysdev_drivers_lock);

 	kobject_unregister(&sysdev->kobj);
 }


 /**
  *	sysdev_shutdown - Shut down all system devices.
  *
  *	Loop over each class of system devices, and the devices in each
  *	of those classes. For each device, we call the shutdown method for
  *	each driver registered for the device - the globals, the auxillaries,
  *	and the class driver.
  *
  *	Note: The list is iterated in reverse order, so that we shut down
  *	child devices before we shut down thier parents. The list ordering
  *	is guaranteed by virtue of the fact that child devices are registered
  *	after their parents.
  */

 void sysdev_shutdown(void)
 {
 	struct sysdev_class * cls;

 	pr_debug("Shutting Down System Devices\n");

 	down(&sysdev_drivers_lock);
 	list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 				    kset.kobj.entry) {
 		struct sys_device * sysdev;

 		pr_debug("Shutting down type '%s':\n",
 			 kobject_name(&cls->kset.kobj));

 		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 			struct sysdev_driver * drv;
 			pr_debug(" %s\n", kobject_name(&sysdev->kobj));

 			/* Call global drivers first. */
 			list_for_each_entry(drv, &sysdev_drivers, entry) {
 				if (drv->shutdown)
 					drv->shutdown(sysdev);
 			}

 			/* Call auxillary drivers next. */
 			list_for_each_entry(drv, &cls->drivers, entry) {
 				if (drv->shutdown)
 					drv->shutdown(sysdev);
 			}

 			/* Now call the generic one */
 			if (cls->shutdown)
 				cls->shutdown(sysdev);
 		}
 	}
 	up(&sysdev_drivers_lock);
 }

 static void __sysdev_resume(struct sys_device *dev)
 {
 	struct sysdev_class *cls = dev->cls;
 	struct sysdev_driver *drv;

 	/* First, call the class-specific one */
 	if (cls->resume)
 		cls->resume(dev);

 	/* Call auxillary drivers next. */
 	list_for_each_entry(drv, &cls->drivers, entry) {
 		if (drv->resume)
 			drv->resume(dev);
 	}

 	/* Call global drivers. */
 	list_for_each_entry(drv, &sysdev_drivers, entry) {
 		if (drv->resume)
 			drv->resume(dev);
 	}
 }

 /**
  *	sysdev_suspend - Suspend all system devices.
  *	@state:		Power state to enter.
  *
  *	We perform an almost identical operation as sys_device_shutdown()
  *	above, though calling ->suspend() instead. Interrupts are disabled
  *	when this called. Devices are responsible for both saving state and
  *	quiescing or powering down the device.
  *
  *	This is only called by the device PM core, so we let them handle
  *	all synchronization.
  */

 int sysdev_suspend(pm_message_t state)
 {
 	struct sysdev_class * cls;
 	struct sys_device *sysdev, *err_dev;
 	struct sysdev_driver *drv, *err_drv;
 	int ret;

 	pr_debug("Suspending System Devices\n");

 	list_for_each_entry_reverse(cls, &system_subsys.kset.list,
 				    kset.kobj.entry) {

 		pr_debug("Suspending type '%s':\n",
 			 kobject_name(&cls->kset.kobj));

 		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 			pr_debug(" %s\n", kobject_name(&sysdev->kobj));

 			/* Call global drivers first. */
 			list_for_each_entry(drv, &sysdev_drivers, entry) {
 				if (drv->suspend) {
 					ret = drv->suspend(sysdev, state);
 					if (ret)
 						goto gbl_driver;
 				}
 			}

 			/* Call auxillary drivers next. */
 			list_for_each_entry(drv, &cls->drivers, entry) {
 				if (drv->suspend) {
 					ret = drv->suspend(sysdev, state);
 					if (ret)
 						goto aux_driver;
 				}
 			}

 			/* Now call the generic one */
 			if (cls->suspend) {
 				ret = cls->suspend(sysdev, state);
 				if (ret)
 					goto cls_driver;
 			}
 		}
 	}
 	return 0;
 	/* resume current sysdev */
 cls_driver:
 	drv = NULL;
 	printk(KERN_ERR "Class suspend failed for %s\n",
 		kobject_name(&sysdev->kobj));

 aux_driver:
 	if (drv)
 		printk(KERN_ERR "Class driver suspend failed for %s\n",
 				kobject_name(&sysdev->kobj));
 	list_for_each_entry(err_drv, &cls->drivers, entry) {
 		if (err_drv == drv)
 			break;
 		if (err_drv->resume)
 			err_drv->resume(sysdev);
 	}
 	drv = NULL;

 gbl_driver:
 	if (drv)
 		printk(KERN_ERR "sysdev driver suspend failed for %s\n",
 				kobject_name(&sysdev->kobj));
 	list_for_each_entry(err_drv, &sysdev_drivers, entry) {
 		if (err_drv == drv)
 			break;
 		if (err_drv->resume)
 			err_drv->resume(sysdev);
 	}
 	/* resume other sysdevs in current class */
 	list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 		if (err_dev == sysdev)
 			break;
 		pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 		__sysdev_resume(err_dev);
 	}

 	/* resume other classes */
 	list_for_each_entry_continue(cls, &system_subsys.kset.list,
 					kset.kobj.entry) {
 		list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
 			pr_debug(" %s\n", kobject_name(&err_dev->kobj));
 			__sysdev_resume(err_dev);
 		}
 	}
 	return ret;
 }


 /**
  *	sysdev_resume - Bring system devices back to life.
  *
  *	Similar to sys_device_suspend(), but we iterate the list forwards
  *	to guarantee that parent devices are resumed before their children.
  *
  *	Note: Interrupts are disabled when called.
  */

 int sysdev_resume(void)
 {
 	struct sysdev_class * cls;

 	pr_debug("Resuming System Devices\n");

 	list_for_each_entry(cls, &system_subsys.kset.list, kset.kobj.entry) {
 		struct sys_device * sysdev;

 		pr_debug("Resuming type '%s':\n",
 			 kobject_name(&cls->kset.kobj));

 		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
 			pr_debug(" %s\n", kobject_name(&sysdev->kobj));

 			__sysdev_resume(sysdev);
 		}
 	}
 	return 0;
 }


 int __init system_bus_init(void)
 {
 	system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
 	return subsystem_register(&system_subsys);
 }

 EXPORT_SYMBOL_GPL(sysdev_register);
 EXPORT_SYMBOL_GPL(sysdev_unregister);
	/*
	* sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
	*
	* Copyright (c) 2002-3 Patrick Mochel
	* 2002-3 Open Source Development Lab
	*
	* This file is released under the GPLv2
	*
	* This exports a 'system' bus type.
	* By default, a 'sys' bus gets added to the root of the system. There will
	* always be core system devices. Devices can use sysdev_register() to
	* add themselves as children of the system bus.
	*/

	#include <linux/config.h>
	#include <linux/sysdev.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/string.h>
	#include <linux/pm.h>

	extern struct subsystem devices_subsys;

	#define to_sysdev(k) container_of(k, struct sys_device, kobj)
	#define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)


	static ssize_t
	sysdev_show(struct kobject * kobj, struct attribute * attr, char * buffer)
	{
	struct sys_device * sysdev = to_sysdev(kobj);
	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);

	if (sysdev_attr->show)
	return sysdev_attr->show(sysdev, buffer);
	return -EIO;
	}


	static ssize_t
	sysdev_store(struct kobject * kobj, struct attribute * attr,
	const char * buffer, size_t count)
	{
	struct sys_device * sysdev = to_sysdev(kobj);
	struct sysdev_attribute * sysdev_attr = to_sysdev_attr(attr);

	if (sysdev_attr->store)
	return sysdev_attr->store(sysdev, buffer, count);
	return -EIO;
	}

	static struct sysfs_ops sysfs_ops = {
	.show = sysdev_show,
	.store = sysdev_store,
	};

	static struct kobj_type ktype_sysdev = {
	.sysfs_ops = &sysfs_ops,
	};


	int sysdev_create_file(struct sys_device * s, struct sysdev_attribute * a)
	{
	return sysfs_create_file(&s->kobj, &a->attr);
	}


	void sysdev_remove_file(struct sys_device * s, struct sysdev_attribute * a)
	{
	sysfs_remove_file(&s->kobj, &a->attr);
	}

	EXPORT_SYMBOL_GPL(sysdev_create_file);
	EXPORT_SYMBOL_GPL(sysdev_remove_file);

	/*
	* declare system_subsys
	*/
	static decl_subsys(system, &ktype_sysdev, NULL);

	int sysdev_class_register(struct sysdev_class * cls)
	{
	pr_debug("Registering sysdev class '%s'\n",
	kobject_name(&cls->kset.kobj));
	INIT_LIST_HEAD(&cls->drivers);
	cls->kset.subsys = &system_subsys;
	kset_set_kset_s(cls, system_subsys);
	return kset_register(&cls->kset);
	}

	void sysdev_class_unregister(struct sysdev_class * cls)
	{
	pr_debug("Unregistering sysdev class '%s'\n",
	kobject_name(&cls->kset.kobj));
	kset_unregister(&cls->kset);
	}

	EXPORT_SYMBOL_GPL(sysdev_class_register);
	EXPORT_SYMBOL_GPL(sysdev_class_unregister);


	static LIST_HEAD(sysdev_drivers);
	static DECLARE_MUTEX(sysdev_drivers_lock);

	/**
	* sysdev_driver_register - Register auxillary driver
	* @cls: Device class driver belongs to.
	* @drv: Driver.
	*
	* If @cls is valid, then @drv is inserted into @cls->drivers to be
	* called on each operation on devices of that class. The refcount
	* of @cls is incremented.
	* Otherwise, @drv is inserted into sysdev_drivers, and called for
	* each device.
	*/

	int sysdev_driver_register(struct sysdev_class * cls,
	struct sysdev_driver * drv)
	{
	down(&sysdev_drivers_lock);
	if (cls && kset_get(&cls->kset)) {
	list_add_tail(&drv->entry, &cls->drivers);

	/* If devices of this class already exist, tell the driver */
	if (drv->add) {
	struct sys_device *dev;
	list_for_each_entry(dev, &cls->kset.list, kobj.entry)
	drv->add(dev);
	}
	} else
	list_add_tail(&drv->entry, &sysdev_drivers);
	up(&sysdev_drivers_lock);
	return 0;
	}


	/**
	* sysdev_driver_unregister - Remove an auxillary driver.
	* @cls: Class driver belongs to.
	* @drv: Driver.
	*/
	void sysdev_driver_unregister(struct sysdev_class * cls,
	struct sysdev_driver * drv)
	{
	down(&sysdev_drivers_lock);
	list_del_init(&drv->entry);
	if (cls) {
	if (drv->remove) {
	struct sys_device *dev;
	list_for_each_entry(dev, &cls->kset.list, kobj.entry)
	drv->remove(dev);
	}
	kset_put(&cls->kset);
	}
	up(&sysdev_drivers_lock);
	}

	EXPORT_SYMBOL_GPL(sysdev_driver_register);
	EXPORT_SYMBOL_GPL(sysdev_driver_unregister);



	/**
	* sysdev_register - add a system device to the tree
	* @sysdev: device in question
	*
	*/
	int sysdev_register(struct sys_device * sysdev)
	{
	int error;
	struct sysdev_class * cls = sysdev->cls;

	if (!cls)
	return -EINVAL;

	/* Make sure the kset is set */
	sysdev->kobj.kset = &cls->kset;

	/* But make sure we point to the right type for sysfs translation */
	sysdev->kobj.ktype = &ktype_sysdev;
	error = kobject_set_name(&sysdev->kobj, "%s%d",
	kobject_name(&cls->kset.kobj), sysdev->id);
	if (error)
	return error;

	pr_debug("Registering sys device '%s'\n", kobject_name(&sysdev->kobj));

	/* Register the object */
	error = kobject_register(&sysdev->kobj);

	if (!error) {
	struct sysdev_driver * drv;

	down(&sysdev_drivers_lock);
	/* Generic notification is implicit, because it's that
	* code that should have called us.
	*/

	/* Notify global drivers */
	list_for_each_entry(drv, &sysdev_drivers, entry) {
	if (drv->add)
	drv->add(sysdev);
	}

	/* Notify class auxillary drivers */
	list_for_each_entry(drv, &cls->drivers, entry) {
	if (drv->add)
	drv->add(sysdev);
	}
	up(&sysdev_drivers_lock);
	}
	return error;
	}

	void sysdev_unregister(struct sys_device * sysdev)
	{
	struct sysdev_driver * drv;

	down(&sysdev_drivers_lock);
	list_for_each_entry(drv, &sysdev_drivers, entry) {
	if (drv->remove)
	drv->remove(sysdev);
	}

	list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
	if (drv->remove)
	drv->remove(sysdev);
	}
	up(&sysdev_drivers_lock);

	kobject_unregister(&sysdev->kobj);
	}



	/**
	* sysdev_shutdown - Shut down all system devices.
	*
	* Loop over each class of system devices, and the devices in each
	* of those classes. For each device, we call the shutdown method for
	* each driver registered for the device - the globals, the auxillaries,
	* and the class driver.
	*
	* Note: The list is iterated in reverse order, so that we shut down
	* child devices before we shut down thier parents. The list ordering
	* is guaranteed by virtue of the fact that child devices are registered
	* after their parents.
	*/

	void sysdev_shutdown(void)
	{
	struct sysdev_class * cls;

	pr_debug("Shutting Down System Devices\n");

	down(&sysdev_drivers_lock);
	list_for_each_entry_reverse(cls, &system_subsys.kset.list,
	kset.kobj.entry) {
	struct sys_device * sysdev;

	pr_debug("Shutting down type '%s':\n",
	kobject_name(&cls->kset.kobj));

	list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
	struct sysdev_driver * drv;
	pr_debug(" %s\n", kobject_name(&sysdev->kobj));

	/* Call global drivers first. */
	list_for_each_entry(drv, &sysdev_drivers, entry) {
	if (drv->shutdown)
	drv->shutdown(sysdev);
	}

	/* Call auxillary drivers next. */
	list_for_each_entry(drv, &cls->drivers, entry) {
	if (drv->shutdown)
	drv->shutdown(sysdev);
	}

	/* Now call the generic one */
	if (cls->shutdown)
	cls->shutdown(sysdev);
	}
	}
	up(&sysdev_drivers_lock);
	}

	static void __sysdev_resume(struct sys_device *dev)
	{
	struct sysdev_class *cls = dev->cls;
	struct sysdev_driver *drv;

	/* First, call the class-specific one */
	if (cls->resume)
	cls->resume(dev);

	/* Call auxillary drivers next. */
	list_for_each_entry(drv, &cls->drivers, entry) {
	if (drv->resume)
	drv->resume(dev);
	}

	/* Call global drivers. */
	list_for_each_entry(drv, &sysdev_drivers, entry) {
	if (drv->resume)
	drv->resume(dev);
	}
	}

	/**
	* sysdev_suspend - Suspend all system devices.
	* @state: Power state to enter.
	*
	* We perform an almost identical operation as sys_device_shutdown()
	* above, though calling ->suspend() instead. Interrupts are disabled
	* when this called. Devices are responsible for both saving state and
	* quiescing or powering down the device.
	*
	* This is only called by the device PM core, so we let them handle
	* all synchronization.
	*/

	int sysdev_suspend(pm_message_t state)
	{
	struct sysdev_class * cls;
	struct sys_device sysdev, err_dev;
	struct sysdev_driver drv, err_drv;
	int ret;

	pr_debug("Suspending System Devices\n");

	list_for_each_entry_reverse(cls, &system_subsys.kset.list,
	kset.kobj.entry) {

	pr_debug("Suspending type '%s':\n",
	kobject_name(&cls->kset.kobj));

	list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
	pr_debug(" %s\n", kobject_name(&sysdev->kobj));

	/* Call global drivers first. */
	list_for_each_entry(drv, &sysdev_drivers, entry) {
	if (drv->suspend) {
	ret = drv->suspend(sysdev, state);
	if (ret)
	goto gbl_driver;
	}
	}

	/* Call auxillary drivers next. */
	list_for_each_entry(drv, &cls->drivers, entry) {
	if (drv->suspend) {
	ret = drv->suspend(sysdev, state);
	if (ret)
	goto aux_driver;
	}
	}

	/* Now call the generic one */
	if (cls->suspend) {
	ret = cls->suspend(sysdev, state);
	if (ret)
	goto cls_driver;
	}
	}
	}
	return 0;
	/* resume current sysdev */
	cls_driver:
	drv = NULL;
	printk(KERN_ERR "Class suspend failed for %s\n",
	kobject_name(&sysdev->kobj));

	aux_driver:
	if (drv)
	printk(KERN_ERR "Class driver suspend failed for %s\n",
	kobject_name(&sysdev->kobj));
	list_for_each_entry(err_drv, &cls->drivers, entry) {
	if (err_drv == drv)
	break;
	if (err_drv->resume)
	err_drv->resume(sysdev);
	}
	drv = NULL;

	gbl_driver:
	if (drv)
	printk(KERN_ERR "sysdev driver suspend failed for %s\n",
	kobject_name(&sysdev->kobj));
	list_for_each_entry(err_drv, &sysdev_drivers, entry) {
	if (err_drv == drv)
	break;
	if (err_drv->resume)
	err_drv->resume(sysdev);
	}
	/* resume other sysdevs in current class */
	list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
	if (err_dev == sysdev)
	break;
	pr_debug(" %s\n", kobject_name(&err_dev->kobj));
	__sysdev_resume(err_dev);
	}

	/* resume other classes */
	list_for_each_entry_continue(cls, &system_subsys.kset.list,
	kset.kobj.entry) {
	list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
	pr_debug(" %s\n", kobject_name(&err_dev->kobj));
	__sysdev_resume(err_dev);
	}
	}
	return ret;
	}


	/**
	* sysdev_resume - Bring system devices back to life.
	*
	* Similar to sys_device_suspend(), but we iterate the list forwards
	* to guarantee that parent devices are resumed before their children.
	*
	* Note: Interrupts are disabled when called.
	*/

	int sysdev_resume(void)
	{
	struct sysdev_class * cls;

	pr_debug("Resuming System Devices\n");

	list_for_each_entry(cls, &system_subsys.kset.list, kset.kobj.entry) {
	struct sys_device * sysdev;

	pr_debug("Resuming type '%s':\n",
	kobject_name(&cls->kset.kobj));

	list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
	pr_debug(" %s\n", kobject_name(&sysdev->kobj));

	__sysdev_resume(sysdev);
	}
	}
	return 0;
	}


	int __init system_bus_init(void)
	{
	system_subsys.kset.kobj.parent = &devices_subsys.kset.kobj;
	return subsystem_register(&system_subsys);
	}

	EXPORT_SYMBOL_GPL(sysdev_register);
	EXPORT_SYMBOL_GPL(sysdev_unregister);