// SPDX-License-Identifier: GPL-2.0 /* * 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. */ #include <linux/device/class.h> #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/blkdev.h> #include <linux/mutex.h> #include "base.h" /* /sys/class */ static struct kset *class_kset; #define to_class_attr(_attr) … /** * class_to_subsys - Turn a struct class into a struct subsys_private * * @class: pointer to the struct bus_type to look up * * The driver core internals need to work on the subsys_private structure, not * the external struct class pointer. This function walks the list of * registered classes in the system and finds the matching one and returns the * internal struct subsys_private that relates to that class. * * Note, the reference count of the return value is INCREMENTED if it is not * NULL. A call to subsys_put() must be done when finished with the pointer in * order for it to be properly freed. */ struct subsys_private *class_to_subsys(const struct class *class) { … } static ssize_t class_attr_show(struct kobject *kobj, struct attribute *attr, char *buf) { … } static ssize_t class_attr_store(struct kobject *kobj, struct attribute *attr, const char *buf, size_t count) { … } static void class_release(struct kobject *kobj) { … } static const struct kobj_ns_type_operations *class_child_ns_type(const struct kobject *kobj) { … } static const struct sysfs_ops class_sysfs_ops = …; static const struct kobj_type class_ktype = …; int class_create_file_ns(const struct class *cls, const struct class_attribute *attr, const void *ns) { … } EXPORT_SYMBOL_GPL(…); void class_remove_file_ns(const struct class *cls, const struct class_attribute *attr, const void *ns) { … } EXPORT_SYMBOL_GPL(…); static struct device *klist_class_to_dev(struct klist_node *n) { … } static void klist_class_dev_get(struct klist_node *n) { … } static void klist_class_dev_put(struct klist_node *n) { … } int class_register(const struct class *cls) { … } EXPORT_SYMBOL_GPL(…); void class_unregister(const struct class *cls) { … } EXPORT_SYMBOL_GPL(…); static void class_create_release(const struct class *cls) { … } /** * class_create - create a struct class structure * @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 device_create(). * * Returns &struct class pointer on success, or ERR_PTR() on error. * * Note, the pointer created here is to be destroyed when finished by * making a call to class_destroy(). */ struct class *class_create(const char *name) { … } EXPORT_SYMBOL_GPL(…); /** * 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(const struct class *cls) { … } EXPORT_SYMBOL_GPL(…); /** * class_dev_iter_init - initialize class device iterator * @iter: class iterator to initialize * @class: the class we wanna iterate over * @start: the device to start iterating from, if any * @type: device_type of the devices to iterate over, NULL for all * * Initialize class iterator @iter such that it iterates over devices * of @class. If @start is set, the list iteration will start there, * otherwise if it is NULL, the iteration starts at the beginning of * the list. */ void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, const struct device *start, const struct device_type *type) { … } EXPORT_SYMBOL_GPL(…); /** * class_dev_iter_next - iterate to the next device * @iter: class iterator to proceed * * Proceed @iter to the next device and return it. Returns NULL if * iteration is complete. * * The returned device is referenced and won't be released till * iterator is proceed to the next device or exited. The caller is * free to do whatever it wants to do with the device including * calling back into class code. */ struct device *class_dev_iter_next(struct class_dev_iter *iter) { … } EXPORT_SYMBOL_GPL(…); /** * class_dev_iter_exit - finish iteration * @iter: class iterator to finish * * Finish an iteration. Always call this function after iteration is * complete whether the iteration ran till the end or not. */ void class_dev_iter_exit(struct class_dev_iter *iter) { … } EXPORT_SYMBOL_GPL(…); /** * class_for_each_device - device iterator * @class: the class we're iterating * @start: the device to start with in the list, if any. * @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. If @start is set, the list iteration will start * there, otherwise if it is NULL, the iteration starts at the * beginning of the list. * * We check the return of @fn each time. If it returns anything * other than 0, we break out and return that value. * * @fn is allowed to do anything including calling back into class * code. There's no locking restriction. */ int class_for_each_device(const struct class *class, const struct device *start, void *data, int (*fn)(struct device *, void *)) { … } EXPORT_SYMBOL_GPL(…); /** * class_find_device - device iterator for locating a particular device * @class: the class we're iterating * @start: Device to begin with * @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. * * @match is allowed to do anything including calling back into class * code. There's no locking restriction. */ struct device *class_find_device(const struct class *class, const struct device *start, const void *data, int (*match)(struct device *, const void *)) { … } EXPORT_SYMBOL_GPL(…); int class_interface_register(struct class_interface *class_intf) { … } EXPORT_SYMBOL_GPL(…); void class_interface_unregister(struct class_interface *class_intf) { … } EXPORT_SYMBOL_GPL(…); ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr, char *buf) { … } EXPORT_SYMBOL_GPL(…); struct class_compat { … }; /** * class_compat_register - register a compatibility class * @name: the name of the class * * Compatibility class are meant as a temporary user-space compatibility * workaround when converting a family of class devices to a bus devices. */ struct class_compat *class_compat_register(const char *name) { … } EXPORT_SYMBOL_GPL(…); /** * class_compat_unregister - unregister a compatibility class * @cls: the class to unregister */ void class_compat_unregister(struct class_compat *cls) { … } EXPORT_SYMBOL_GPL(…); /** * class_compat_create_link - create a compatibility class device link to * a bus device * @cls: the compatibility class * @dev: the target bus device * @device_link: an optional device to which a "device" link should be created */ int class_compat_create_link(struct class_compat *cls, struct device *dev, struct device *device_link) { … } EXPORT_SYMBOL_GPL(…); /** * class_compat_remove_link - remove a compatibility class device link to * a bus device * @cls: the compatibility class * @dev: the target bus device * @device_link: an optional device to which a "device" link was previously * created */ void class_compat_remove_link(struct class_compat *cls, struct device *dev, struct device *device_link) { … } EXPORT_SYMBOL_GPL(…); /** * class_is_registered - determine if at this moment in time, a class is * registered in the driver core or not. * @class: the class to check * * Returns a boolean to state if the class is registered in the driver core * or not. Note that the value could switch right after this call is made, * so only use this in places where you "know" it is safe to do so (usually * to determine if the specific class has been registered yet or not). * * Be careful in using this. */ bool class_is_registered(const struct class *class) { … } EXPORT_SYMBOL_GPL(…); int __init classes_init(void) { … }
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