Skip to content
Snippets Groups Projects
Select Git revision
  • 29a020d35f629619c67fa5e32acaaac3f8a1ba90
  • master default protected
  • android-msm-bullhead-3.10-nougat_kgdb_less_changes
  • android-msm-bullhead-3.10-nougat_kgdb
  • android-msm-bullhead-3.10-nougat_klist
  • android-4.4
  • android-msm-vega-4.4-oreo-daydream
  • android-msm-wahoo-4.4-p-preview-5
  • android-msm-wahoo-4.4-pie
  • android-msm-marlin-3.18-p-preview-5
  • android-msm-marlin-3.18-pie
  • android-msm-wahoo-2018.07-oreo-m2
  • android-msm-wahoo-2018.07-oreo-m4
  • android-msm-wahoo-4.4-p-preview-4
  • android-msm-bullhead-3.10-oreo-m6
  • android-msm-angler-3.10-oreo-m6
  • android-msm-marlin-3.18-p-preview-4
  • android-msm-stargazer-3.18-oreo-wear-dr
  • android-msm-catshark-3.18-oreo-wear-dr
  • android-msm-wahoo-4.4-oreo-m2
  • android-msm-wahoo-4.4-oreo-m4
  • android-daydreamos-8.0.0_r0.5
  • android-8.1.0_r0.92
  • android-8.1.0_r0.91
  • android-daydreamos-8.0.0_r0.4
  • android-p-preview-5_r0.2
  • android-p-preview-5_r0.1
  • android-9.0.0_r0.5
  • android-9.0.0_r0.4
  • android-9.0.0_r0.2
  • android-9.0.0_r0.1
  • android-8.1.0_r0.81
  • android-8.1.0_r0.80
  • android-8.1.0_r0.78
  • android-8.1.0_r0.76
  • android-8.1.0_r0.75
  • android-8.1.0_r0.72
  • android-8.1.0_r0.70
  • android-p-preview-4_r0.2
  • android-p-preview-4_r0.1
  • android-wear-8.0.0_r0.30
41 results

net.h

Blame
  • class.c 25.32 KiB
    /*
     * class.c - basic device class management
     *
     * Copyright (c) 2002-3 Patrick Mochel
     * Copyright (c) 2002-3 Open Source Development Labs
     * Copyright (c) 2003-2004 Greg Kroah-Hartman
     * Copyright (c) 2003-2004 IBM Corp.
     *
     * This file is released under the GPLv2
     *
     */
    
    #include <linux/device.h>
    #include <linux/module.h>
    #include <linux/init.h>
    #include <linux/string.h>
    #include <linux/kdev_t.h>
    #include <linux/err.h>
    #include <linux/slab.h>
    #include <linux/genhd.h>
    #include "base.h"
    
    #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
    #define to_class(obj) container_of(obj, struct class, subsys.kobj)
    
    static ssize_t
    class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
    {
    	struct class_attribute * class_attr = to_class_attr(attr);
    	struct class * dc = to_class(kobj);
    	ssize_t ret = -EIO;
    
    	if (class_attr->show)
    		ret = class_attr->show(dc, buf);
    	return ret;
    }
    
    static ssize_t
    class_attr_store(struct kobject * kobj, struct attribute * attr,
    		 const char * buf, size_t count)
    {
    	struct class_attribute * class_attr = to_class_attr(attr);
    	struct class * dc = to_class(kobj);
    	ssize_t ret = -EIO;
    
    	if (class_attr->store)
    		ret = class_attr->store(dc, buf, count);
    	return ret;
    }
    
    static void class_release(struct kobject * kobj)
    {
    	struct class *class = to_class(kobj);
    
    	pr_debug("class '%s': release.\n", class->name);
    
    	if (class->class_release)
    		class->class_release(class);
    	else
    		pr_debug("class '%s' does not have a release() function, "
    			 "be careful\n", class->name);
    }
    
    static struct sysfs_ops class_sysfs_ops = {
    	.show	= class_attr_show,
    	.store	= class_attr_store,
    };
    
    static struct kobj_type class_ktype = {
    	.sysfs_ops	= &class_sysfs_ops,
    	.release	= class_release,
    };
    
    /* Hotplug events for classes go to the class_obj subsys */
    static struct kset *class_kset;
    
    
    int class_create_file(struct class * cls, const struct class_attribute * attr)
    {
    	int error;
    	if (cls) {
    		error = sysfs_create_file(&cls->subsys.kobj, &attr->attr);
    	} else
    		error = -EINVAL;
    	return error;
    }
    
    void class_remove_file(struct class * cls, const struct class_attribute * attr)
    {
    	if (cls)
    		sysfs_remove_file(&cls->subsys.kobj, &attr->attr);
    }
    
    static struct class *class_get(struct class *cls)
    {
    	if (cls)
    		return container_of(kset_get(&cls->subsys), struct class, subsys);
    	return NULL;
    }
    
    static void class_put(struct class * cls)
    {
    	if (cls)
    		kset_put(&cls->subsys);
    }
    
    
    static int add_class_attrs(struct class * cls)
    {
    	int i;
    	int error = 0;
    
    	if (cls->class_attrs) {
    		for (i = 0; attr_name(cls->class_attrs[i]); i++) {
    			error = class_create_file(cls,&cls->class_attrs[i]);
    			if (error)
    				goto Err;
    		}
    	}
     Done:
    	return error;
     Err:
    	while (--i >= 0)
    		class_remove_file(cls,&cls->class_attrs[i]);
    	goto Done;
    }
    
    static void remove_class_attrs(struct class * cls)
    {
    	int i;
    
    	if (cls->class_attrs) {
    		for (i = 0; attr_name(cls->class_attrs[i]); i++)
    			class_remove_file(cls,&cls->class_attrs[i]);
    	}
    }
    
    int class_register(struct class * cls)
    {
    	int error;
    
    	pr_debug("device class '%s': registering\n", cls->name);
    
    	INIT_LIST_HEAD(&cls->children);
    	INIT_LIST_HEAD(&cls->devices);
    	INIT_LIST_HEAD(&cls->interfaces);
    	kset_init(&cls->class_dirs);
    	init_MUTEX(&cls->sem);
    	error = kobject_set_name(&cls->subsys.kobj, "%s", cls->name);
    	if (error)
    		return error;
    
    #ifdef CONFIG_SYSFS_DEPRECATED
    	/* let the block class directory show up in the root of sysfs */
    	if (cls != &block_class)
    		cls->subsys.kobj.kset = class_kset;
    #else
    	cls->subsys.kobj.kset = class_kset;
    #endif
    	cls->subsys.kobj.ktype = &class_ktype;
    
    	error = kset_register(&cls->subsys);
    	if (!error) {
    		error = add_class_attrs(class_get(cls));
    		class_put(cls);
    	}
    	return error;
    }
    
    void class_unregister(struct class * cls)
    {
    	pr_debug("device class '%s': unregistering\n", cls->name);
    	remove_class_attrs(cls);
    	kset_unregister(&cls->subsys);
    }
    
    static void class_create_release(struct class *cls)
    {
    	pr_debug("%s called for %s\n", __FUNCTION__, cls->name);
    	kfree(cls);
    }
    
    static void class_device_create_release(struct class_device *class_dev)
    {
    	pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
    	kfree(class_dev);
    }
    
    /* needed to allow these devices to have parent class devices */
    static int class_device_create_uevent(struct class_device *class_dev,
    				      struct kobj_uevent_env *env)
    {
    	pr_debug("%s called for %s\n", __FUNCTION__, class_dev->class_id);
    	return 0;
    }
    
    /**
     * class_create - create a struct class structure
     * @owner: pointer to the module that is to "own" this struct class
     * @name: pointer to a string for the name of this class.
     *
     * This is used to create a struct class pointer that can then be used
     * in calls to class_device_create().
     *
     * Note, the pointer created here is to be destroyed when finished by
     * making a call to class_destroy().
     */
    struct class *class_create(struct module *owner, const char *name)
    {
    	struct class *cls;
    	int retval;
    
    	cls = kzalloc(sizeof(*cls), GFP_KERNEL);
    	if (!cls) {
    		retval = -ENOMEM;
    		goto error;
    	}
    
    	cls->name = name;
    	cls->owner = owner;
    	cls->class_release = class_create_release;
    	cls->release = class_device_create_release;
    
    	retval = class_register(cls);
    	if (retval)
    		goto error;
    
    	return cls;
    
    error:
    	kfree(cls);
    	return ERR_PTR(retval);
    }
    
    /**
     * class_destroy - destroys a struct class structure
     * @cls: pointer to the struct class that is to be destroyed
     *
     * Note, the pointer to be destroyed must have been created with a call
     * to class_create().
     */
    void class_destroy(struct class *cls)
    {
    	if ((cls == NULL) || (IS_ERR(cls)))
    		return;
    
    	class_unregister(cls);
    }
    
    /* Class Device Stuff */
    
    int class_device_create_file(struct class_device * class_dev,
    			     const struct class_device_attribute * attr)
    {
    	int error = -EINVAL;
    	if (class_dev)
    		error = sysfs_create_file(&class_dev->kobj, &attr->attr);
    	return error;
    }
    
    void class_device_remove_file(struct class_device * class_dev,
    			      const struct class_device_attribute * attr)
    {
    	if (class_dev)
    		sysfs_remove_file(&class_dev->kobj, &attr->attr);
    }
    
    int class_device_create_bin_file(struct class_device *class_dev,
    				 struct bin_attribute *attr)
    {
    	int error = -EINVAL;
    	if (class_dev)
    		error = sysfs_create_bin_file(&class_dev->kobj, attr);
    	return error;
    }
    
    void class_device_remove_bin_file(struct class_device *class_dev,
    				  struct bin_attribute *attr)
    {
    	if (class_dev)
    		sysfs_remove_bin_file(&class_dev->kobj, attr);
    }
    
    static ssize_t
    class_device_attr_show(struct kobject * kobj, struct attribute * attr,
    		       char * buf)
    {
    	struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
    	struct class_device * cd = to_class_dev(kobj);
    	ssize_t ret = 0;
    
    	if (class_dev_attr->show)
    		ret = class_dev_attr->show(cd, buf);
    	return ret;
    }
    
    static ssize_t
    class_device_attr_store(struct kobject * kobj, struct attribute * attr,
    			const char * buf, size_t count)
    {
    	struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
    	struct class_device * cd = to_class_dev(kobj);
    	ssize_t ret = 0;
    
    	if (class_dev_attr->store)
    		ret = class_dev_attr->store(cd, buf, count);
    	return ret;
    }
    
    static struct sysfs_ops class_dev_sysfs_ops = {
    	.show	= class_device_attr_show,
    	.store	= class_device_attr_store,
    };
    
    static void class_dev_release(struct kobject * kobj)
    {
    	struct class_device *cd = to_class_dev(kobj);
    	struct class * cls = cd->class;
    
    	pr_debug("device class '%s': release.\n", cd->class_id);
    
    	if (cd->release)
    		cd->release(cd);
    	else if (cls->release)
    		cls->release(cd);
    	else {
    		printk(KERN_ERR "Class Device '%s' does not have a release() function, "
    			"it is broken and must be fixed.\n",
    			cd->class_id);
    		WARN_ON(1);
    	}
    }
    
    static struct kobj_type class_device_ktype = {
    	.sysfs_ops	= &class_dev_sysfs_ops,
    	.release	= class_dev_release,
    };
    
    static int class_uevent_filter(struct kset *kset, struct kobject *kobj)
    {
    	struct kobj_type *ktype = get_ktype(kobj);
    
    	if (ktype == &class_device_ktype) {
    		struct class_device *class_dev = to_class_dev(kobj);
    		if (class_dev->class)
    			return 1;
    	}
    	return 0;
    }
    
    static const char *class_uevent_name(struct kset *kset, struct kobject *kobj)
    {
    	struct class_device *class_dev = to_class_dev(kobj);
    
    	return class_dev->class->name;
    }
    
    #ifdef CONFIG_SYSFS_DEPRECATED
    char *make_class_name(const char *name, struct kobject *kobj)
    {
    	char *class_name;
    	int size;
    
    	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
    
    	class_name = kmalloc(size, GFP_KERNEL);
    	if (!class_name)
    		return NULL;
    
    	strcpy(class_name, name);
    	strcat(class_name, ":");
    	strcat(class_name, kobject_name(kobj));
    	return class_name;
    }
    
    static int make_deprecated_class_device_links(struct class_device *class_dev)
    {
    	char *class_name;
    	int error;
    
    	if (!class_dev->dev)
    		return 0;
    
    	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
    	if (class_name)
    		error = sysfs_create_link(&class_dev->dev->kobj,
    					  &class_dev->kobj, class_name);
    	else
    		error = -ENOMEM;
    	kfree(class_name);
    	return error;
    }
    
    static void remove_deprecated_class_device_links(struct class_device *class_dev)
    {
    	char *class_name;
    
    	if (!class_dev->dev)
    		return;
    
    	class_name = make_class_name(class_dev->class->name, &class_dev->kobj);
    	if (class_name)
    		sysfs_remove_link(&class_dev->dev->kobj, class_name);
    	kfree(class_name);
    }
    #else
    static inline int make_deprecated_class_device_links(struct class_device *cd)
    { return 0; }
    static void remove_deprecated_class_device_links(struct class_device *cd)
    { }
    #endif
    
    static int class_uevent(struct kset *kset, struct kobject *kobj,
    			struct kobj_uevent_env *env)
    {
    	struct class_device *class_dev = to_class_dev(kobj);
    	struct device *dev = class_dev->dev;
    	int retval = 0;
    
    	pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
    
    	if (MAJOR(class_dev->devt)) {
    		add_uevent_var(env, "MAJOR=%u", MAJOR(class_dev->devt));
    
    		add_uevent_var(env, "MINOR=%u", MINOR(class_dev->devt));
    	}
    
    	if (dev) {
    		const char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
    		if (path) {
    			add_uevent_var(env, "PHYSDEVPATH=%s", path);
    			kfree(path);
    		}
    
    		if (dev->bus)
    			add_uevent_var(env, "PHYSDEVBUS=%s", dev->bus->name);
    
    		if (dev->driver)
    			add_uevent_var(env, "PHYSDEVDRIVER=%s", dev->driver->name);
    	}
    
    	if (class_dev->uevent) {
    		/* have the class device specific function add its stuff */
    		retval = class_dev->uevent(class_dev, env);
    		if (retval)
    			pr_debug("class_dev->uevent() returned %d\n", retval);
    	} else if (class_dev->class->uevent) {
    		/* have the class specific function add its stuff */
    		retval = class_dev->class->uevent(class_dev, env);
    		if (retval)
    			pr_debug("class->uevent() returned %d\n", retval);
    	}
    
    	return retval;
    }
    
    static struct kset_uevent_ops class_uevent_ops = {
    	.filter =	class_uevent_filter,
    	.name =		class_uevent_name,
    	.uevent =	class_uevent,
    };
    
    /*
     * DO NOT copy how this is created, kset_create_and_add() should be
     * called, but this is a hold-over from the old-way and will be deleted
     * entirely soon.
     */
    static struct kset class_obj_subsys = {
    	.uevent_ops = &class_uevent_ops,
    };
    
    static int class_device_add_attrs(struct class_device * cd)
    {
    	int i;
    	int error = 0;
    	struct class * cls = cd->class;
    
    	if (cls->class_dev_attrs) {
    		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
    			error = class_device_create_file(cd,
    							 &cls->class_dev_attrs[i]);
    			if (error)
    				goto Err;
    		}
    	}
     Done:
    	return error;
     Err:
    	while (--i >= 0)
    		class_device_remove_file(cd,&cls->class_dev_attrs[i]);
    	goto Done;
    }
    
    static void class_device_remove_attrs(struct class_device * cd)
    {
    	int i;
    	struct class * cls = cd->class;
    
    	if (cls->class_dev_attrs) {
    		for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
    			class_device_remove_file(cd,&cls->class_dev_attrs[i]);
    	}
    }
    
    static int class_device_add_groups(struct class_device * cd)
    {
    	int i;
    	int error = 0;
    
    	if (cd->groups) {
    		for (i = 0; cd->groups[i]; i++) {
    			error = sysfs_create_group(&cd->kobj, cd->groups[i]);
    			if (error) {
    				while (--i >= 0)
    					sysfs_remove_group(&cd->kobj, cd->groups[i]);
    				goto out;
    			}
    		}
    	}
    out:
    	return error;
    }
    
    static void class_device_remove_groups(struct class_device * cd)
    {
    	int i;
    	if (cd->groups) {
    		for (i = 0; cd->groups[i]; i++) {
    			sysfs_remove_group(&cd->kobj, cd->groups[i]);
    		}
    	}
    }
    
    static ssize_t show_dev(struct class_device *class_dev, char *buf)
    {
    	return print_dev_t(buf, class_dev->devt);
    }
    
    static struct class_device_attribute class_devt_attr =
    	__ATTR(dev, S_IRUGO, show_dev, NULL);
    
    static ssize_t store_uevent(struct class_device *class_dev,
    			    const char *buf, size_t count)
    {
    	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
    	return count;
    }
    
    static struct class_device_attribute class_uevent_attr =
    	__ATTR(uevent, S_IWUSR, NULL, store_uevent);
    
    void class_device_initialize(struct class_device *class_dev)
    {
    	class_dev->kobj.kset = &class_obj_subsys;
    	kobject_init(&class_dev->kobj, &class_device_ktype);
    	INIT_LIST_HEAD(&class_dev->node);
    }
    
    int class_device_add(struct class_device *class_dev)
    {
    	struct class *parent_class = NULL;
    	struct class_device *parent_class_dev = NULL;
    	struct class_interface *class_intf;
    	int error = -EINVAL;
    
    	class_dev = class_device_get(class_dev);
    	if (!class_dev)
    		return -EINVAL;
    
    	if (!strlen(class_dev->class_id))
    		goto out1;
    
    	parent_class = class_get(class_dev->class);
    	if (!parent_class)
    		goto out1;
    
    	parent_class_dev = class_device_get(class_dev->parent);
    
    	pr_debug("CLASS: registering class device: ID = '%s'\n",
    		 class_dev->class_id);
    
    	/* first, register with generic layer. */
    	if (parent_class_dev)
    		class_dev->kobj.parent = &parent_class_dev->kobj;
    	else
    		class_dev->kobj.parent = &parent_class->subsys.kobj;
    
    	error = kobject_add(&class_dev->kobj, class_dev->kobj.parent,
    			    "%s", class_dev->class_id);
    	if (error)
    		goto out2;
    
    	/* add the needed attributes to this device */
    	error = sysfs_create_link(&class_dev->kobj,
    				  &parent_class->subsys.kobj, "subsystem");
    	if (error)
    		goto out3;
    
    	error = class_device_create_file(class_dev, &class_uevent_attr);
    	if (error)
    		goto out3;
    
    	if (MAJOR(class_dev->devt)) {
    		error = class_device_create_file(class_dev, &class_devt_attr);
    		if (error)
    			goto out4;
    	}
    
    	error = class_device_add_attrs(class_dev);
    	if (error)
    		goto out5;
    
    	if (class_dev->dev) {
    		error = sysfs_create_link(&class_dev->kobj,
    					  &class_dev->dev->kobj, "device");
    		if (error)
    			goto out6;
    	}
    
    	error = class_device_add_groups(class_dev);
    	if (error)
    		goto out7;
    
    	error = make_deprecated_class_device_links(class_dev);
    	if (error)
    		goto out8;
    
    	kobject_uevent(&class_dev->kobj, KOBJ_ADD);
    
    	/* notify any interfaces this device is now here */
    	down(&parent_class->sem);
    	list_add_tail(&class_dev->node, &parent_class->children);
    	list_for_each_entry(class_intf, &parent_class->interfaces, node) {
    		if (class_intf->add)
    			class_intf->add(class_dev, class_intf);
    	}
    	up(&parent_class->sem);
    
    	goto out1;
    
     out8:
    	class_device_remove_groups(class_dev);
     out7:
    	if (class_dev->dev)
    		sysfs_remove_link(&class_dev->kobj, "device");
     out6:
    	class_device_remove_attrs(class_dev);
     out5:
    	if (MAJOR(class_dev->devt))
    		class_device_remove_file(class_dev, &class_devt_attr);
     out4:
    	class_device_remove_file(class_dev, &class_uevent_attr);
     out3:
    	kobject_del(&class_dev->kobj);
     out2:
    	if(parent_class_dev)
    		class_device_put(parent_class_dev);
    	class_put(parent_class);
     out1:
    	class_device_put(class_dev);
    	return error;
    }
    
    int class_device_register(struct class_device *class_dev)
    {
    	class_device_initialize(class_dev);
    	return class_device_add(class_dev);
    }
    
    /**
     * class_device_create - creates a class device and registers it with sysfs
     * @cls: pointer to the struct class that this device should be registered to.
     * @parent: pointer to the parent struct class_device of this new device, if any.
     * @devt: the dev_t for the char device to be added.
     * @device: a pointer to a struct device that is assiociated with this class device.
     * @fmt: string for the class device's name
     *
     * This function can be used by char device classes.  A struct
     * class_device will be created in sysfs, registered to the specified
     * class.
     * A "dev" file will be created, showing the dev_t for the device, if
     * the dev_t is not 0,0.
     * If a pointer to a parent struct class_device is passed in, the newly
     * created struct class_device will be a child of that device in sysfs.
     * The pointer to the struct class_device will be returned from the
     * call.  Any further sysfs files that might be required can be created
     * using this pointer.
     *
     * Note: the struct class passed to this function must have previously
     * been created with a call to class_create().
     */
    struct class_device *class_device_create(struct class *cls,
    					 struct class_device *parent,
    					 dev_t devt,
    					 struct device *device,
    					 const char *fmt, ...)
    {
    	va_list args;
    	struct class_device *class_dev = NULL;
    	int retval = -ENODEV;
    
    	if (cls == NULL || IS_ERR(cls))
    		goto error;
    
    	class_dev = kzalloc(sizeof(*class_dev), GFP_KERNEL);
    	if (!class_dev) {
    		retval = -ENOMEM;
    		goto error;
    	}
    
    	class_dev->devt = devt;
    	class_dev->dev = device;
    	class_dev->class = cls;
    	class_dev->parent = parent;
    	class_dev->release = class_device_create_release;
    	class_dev->uevent = class_device_create_uevent;
    
    	va_start(args, fmt);
    	vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
    	va_end(args);
    	retval = class_device_register(class_dev);
    	if (retval)
    		goto error;
    
    	return class_dev;
    
    error:
    	kfree(class_dev);
    	return ERR_PTR(retval);
    }
    
    void class_device_del(struct class_device *class_dev)
    {
    	struct class *parent_class = class_dev->class;
    	struct class_device *parent_device = class_dev->parent;
    	struct class_interface *class_intf;
    
    	if (parent_class) {
    		down(&parent_class->sem);
    		list_del_init(&class_dev->node);
    		list_for_each_entry(class_intf, &parent_class->interfaces, node)
    			if (class_intf->remove)
    				class_intf->remove(class_dev, class_intf);
    		up(&parent_class->sem);
    	}
    
    	if (class_dev->dev) {
    		remove_deprecated_class_device_links(class_dev);
    		sysfs_remove_link(&class_dev->kobj, "device");
    	}
    	sysfs_remove_link(&class_dev->kobj, "subsystem");
    	class_device_remove_file(class_dev, &class_uevent_attr);
    	if (MAJOR(class_dev->devt))
    		class_device_remove_file(class_dev, &class_devt_attr);
    	class_device_remove_attrs(class_dev);
    	class_device_remove_groups(class_dev);
    
    	kobject_uevent(&class_dev->kobj, KOBJ_REMOVE);
    	kobject_del(&class_dev->kobj);
    
    	class_device_put(parent_device);
    	class_put(parent_class);
    }
    
    void class_device_unregister(struct class_device *class_dev)
    {
    	pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
    		 class_dev->class_id);
    	class_device_del(class_dev);
    	class_device_put(class_dev);
    }
    
    /**
     * class_device_destroy - removes a class device that was created with class_device_create()
     * @cls: the pointer to the struct class that this device was registered * with.
     * @devt: the dev_t of the device that was previously registered.
     *
     * This call unregisters and cleans up a class device that was created with a
     * call to class_device_create()
     */
    void class_device_destroy(struct class *cls, dev_t devt)
    {
    	struct class_device *class_dev = NULL;
    	struct class_device *class_dev_tmp;
    
    	down(&cls->sem);
    	list_for_each_entry(class_dev_tmp, &cls->children, node) {
    		if (class_dev_tmp->devt == devt) {
    			class_dev = class_dev_tmp;
    			break;
    		}
    	}
    	up(&cls->sem);
    
    	if (class_dev)
    		class_device_unregister(class_dev);
    }
    
    struct class_device * class_device_get(struct class_device *class_dev)
    {
    	if (class_dev)
    		return to_class_dev(kobject_get(&class_dev->kobj));
    	return NULL;
    }
    
    void class_device_put(struct class_device *class_dev)
    {
    	if (class_dev)
    		kobject_put(&class_dev->kobj);
    }
    
    /**
     * class_for_each_device - device iterator
     * @class: the class we're iterating
     * @data: data for the callback
     * @fn: function to be called for each device
     *
     * Iterate over @class's list of devices, and call @fn for each,
     * passing it @data.
     *
     * We check the return of @fn each time. If it returns anything
     * other than 0, we break out and return that value.
     *
     * Note, we hold class->sem in this function, so it can not be
     * re-acquired in @fn, otherwise it will self-deadlocking. For
     * example, calls to add or remove class members would be verboten.
     */
    int class_for_each_device(struct class *class, void *data,
    			   int (*fn)(struct device *, void *))
    {
    	struct device *dev;
    	int error = 0;
    
    	if (!class)
    		return -EINVAL;
    	down(&class->sem);
    	list_for_each_entry(dev, &class->devices, node) {
    		dev = get_device(dev);
    		if (dev) {
    			error = fn(dev, data);
    			put_device(dev);
    		} else
    			error = -ENODEV;
    		if (error)
    			break;
    	}
    	up(&class->sem);
    
    	return error;
    }
    EXPORT_SYMBOL_GPL(class_for_each_device);
    
    /**
     * class_find_device - device iterator for locating a particular device
     * @class: the class we're iterating
     * @data: data for the match function
     * @match: function to check device
     *
     * This is similar to the class_for_each_dev() function above, but it
     * returns a reference to a device that is 'found' for later use, as
     * determined by the @match callback.
     *
     * The callback should return 0 if the device doesn't match and non-zero
     * if it does.  If the callback returns non-zero, this function will
     * return to the caller and not iterate over any more devices.
    
     * Note, you will need to drop the reference with put_device() after use.
     *
     * We hold class->sem in this function, so it can not be
     * re-acquired in @match, otherwise it will self-deadlocking. For
     * example, calls to add or remove class members would be verboten.
     */
    struct device *class_find_device(struct class *class, void *data,
    				   int (*match)(struct device *, void *))
    {
    	struct device *dev;
    	int found = 0;
    
    	if (!class)
    		return NULL;
    
    	down(&class->sem);
    	list_for_each_entry(dev, &class->devices, node) {
    		dev = get_device(dev);
    		if (dev) {
    			if (match(dev, data)) {
    				found = 1;
    				break;
    			} else
    				put_device(dev);
    		} else
    			break;
    	}
    	up(&class->sem);
    
    	return found ? dev : NULL;
    }
    EXPORT_SYMBOL_GPL(class_find_device);
    
    /**
     * class_find_child - device iterator for locating a particular class_device
     * @class: the class we're iterating
     * @data: data for the match function
     * @match: function to check class_device
     *
     * This function returns a reference to a class_device that is 'found' for
     * later use, as determined by the @match callback.
     *
     * The callback should return 0 if the class_device doesn't match and non-zero
     * if it does.  If the callback returns non-zero, this function will
     * return to the caller and not iterate over any more class_devices.
     *
     * Note, you will need to drop the reference with class_device_put() after use.
     *
     * We hold class->sem in this function, so it can not be
     * re-acquired in @match, otherwise it will self-deadlocking. For
     * example, calls to add or remove class members would be verboten.
     */
    struct class_device *class_find_child(struct class *class, void *data,
    				   int (*match)(struct class_device *, void *))
    {
    	struct class_device *dev;
    	int found = 0;
    
    	if (!class)
    		return NULL;
    
    	down(&class->sem);
    	list_for_each_entry(dev, &class->children, node) {
    		dev = class_device_get(dev);
    		if (dev) {
    			if (match(dev, data)) {
    				found = 1;
    				break;
    			} else
    				class_device_put(dev);
    		} else
    			break;
    	}
    	up(&class->sem);
    
    	return found ? dev : NULL;
    }
    EXPORT_SYMBOL_GPL(class_find_child);
    
    int class_interface_register(struct class_interface *class_intf)
    {
    	struct class *parent;
    	struct class_device *class_dev;
    	struct device *dev;
    
    	if (!class_intf || !class_intf->class)
    		return -ENODEV;
    
    	parent = class_get(class_intf->class);
    	if (!parent)
    		return -EINVAL;
    
    	down(&parent->sem);
    	list_add_tail(&class_intf->node, &parent->interfaces);
    	if (class_intf->add) {
    		list_for_each_entry(class_dev, &parent->children, node)
    			class_intf->add(class_dev, class_intf);
    	}
    	if (class_intf->add_dev) {
    		list_for_each_entry(dev, &parent->devices, node)
    			class_intf->add_dev(dev, class_intf);
    	}
    	up(&parent->sem);
    
    	return 0;
    }
    
    void class_interface_unregister(struct class_interface *class_intf)
    {
    	struct class * parent = class_intf->class;
    	struct class_device *class_dev;
    	struct device *dev;
    
    	if (!parent)
    		return;
    
    	down(&parent->sem);
    	list_del_init(&class_intf->node);
    	if (class_intf->remove) {
    		list_for_each_entry(class_dev, &parent->children, node)
    			class_intf->remove(class_dev, class_intf);
    	}
    	if (class_intf->remove_dev) {
    		list_for_each_entry(dev, &parent->devices, node)
    			class_intf->remove_dev(dev, class_intf);
    	}
    	up(&parent->sem);
    
    	class_put(parent);
    }
    
    int __init classes_init(void)
    {
    	class_kset = kset_create_and_add("class", NULL, NULL);
    	if (!class_kset)
    		return -ENOMEM;
    
    	/* ick, this is ugly, the things we go through to keep from showing up
    	 * in sysfs... */
    	kset_init(&class_obj_subsys);
    	kobject_set_name(&class_obj_subsys.kobj, "class_obj");
    	if (!class_obj_subsys.kobj.parent)
    		class_obj_subsys.kobj.parent = &class_obj_subsys.kobj;
    	return 0;
    }
    
    EXPORT_SYMBOL_GPL(class_create_file);
    EXPORT_SYMBOL_GPL(class_remove_file);
    EXPORT_SYMBOL_GPL(class_register);
    EXPORT_SYMBOL_GPL(class_unregister);
    EXPORT_SYMBOL_GPL(class_create);
    EXPORT_SYMBOL_GPL(class_destroy);
    
    EXPORT_SYMBOL_GPL(class_device_register);
    EXPORT_SYMBOL_GPL(class_device_unregister);
    EXPORT_SYMBOL_GPL(class_device_initialize);
    EXPORT_SYMBOL_GPL(class_device_add);
    EXPORT_SYMBOL_GPL(class_device_del);
    EXPORT_SYMBOL_GPL(class_device_get);
    EXPORT_SYMBOL_GPL(class_device_put);
    EXPORT_SYMBOL_GPL(class_device_create);
    EXPORT_SYMBOL_GPL(class_device_destroy);
    EXPORT_SYMBOL_GPL(class_device_create_file);
    EXPORT_SYMBOL_GPL(class_device_remove_file);
    EXPORT_SYMBOL_GPL(class_device_create_bin_file);
    EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
    
    EXPORT_SYMBOL_GPL(class_interface_register);
    EXPORT_SYMBOL_GPL(class_interface_unregister);