1// SPDX-License-Identifier: GPL-2.0
2/*
3 * The class-specific portions of the driver model
4 *
5 * Copyright (c) 2001-2003 Patrick Mochel <mochel@osdl.org>
6 * Copyright (c) 2004-2009 Greg Kroah-Hartman <gregkh@suse.de>
7 * Copyright (c) 2008-2009 Novell Inc.
8 * Copyright (c) 2012-2019 Greg Kroah-Hartman <gregkh@linuxfoundation.org>
9 * Copyright (c) 2012-2019 Linux Foundation
10 *
11 * See Documentation/driver-api/driver-model/ for more information.
12 */
13
14#ifndef _DEVICE_CLASS_H_
15#define _DEVICE_CLASS_H_
16
17#include <linux/kobject.h>
18#include <linux/klist.h>
19#include <linux/pm.h>
20#include <linux/device/bus.h>
21
22struct device;
23struct fwnode_handle;
24
25/**
26 * struct class - device classes
27 * @name: Name of the class.
28 * @class_groups: Default attributes of this class.
29 * @dev_groups: Default attributes of the devices that belong to the class.
30 * @dev_uevent: Called when a device is added, removed from this class, or a
31 * few other things that generate uevents to add the environment
32 * variables.
33 * @devnode: Callback to provide the devtmpfs.
34 * @class_release: Called to release this class.
35 * @dev_release: Called to release the device.
36 * @shutdown_pre: Called at shut-down time before driver shutdown.
37 * @ns_type: Callbacks so sysfs can detemine namespaces.
38 * @namespace: Namespace of the device belongs to this class.
39 * @get_ownership: Allows class to specify uid/gid of the sysfs directories
40 * for the devices belonging to the class. Usually tied to
41 * device's namespace.
42 * @pm: The default device power management operations of this class.
43 *
44 * A class is a higher-level view of a device that abstracts out low-level
45 * implementation details. Drivers may see a SCSI disk or an ATA disk, but,
46 * at the class level, they are all simply disks. Classes allow user space
47 * to work with devices based on what they do, rather than how they are
48 * connected or how they work.
49 */
50struct class {
51 const char *name;
52
53 const struct attribute_group **class_groups;
54 const struct attribute_group **dev_groups;
55
56 int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env);
57 char *(*devnode)(const struct device *dev, umode_t *mode);
58
59 void (*class_release)(const struct class *class);
60 void (*dev_release)(struct device *dev);
61
62 int (*shutdown_pre)(struct device *dev);
63
64 const struct kobj_ns_type_operations *ns_type;
65 const void *(*namespace)(const struct device *dev);
66
67 void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid);
68
69 const struct dev_pm_ops *pm;
70};
71
72struct class_dev_iter {
73 struct klist_iter ki;
74 const struct device_type *type;
75 struct subsys_private *sp;
76};
77
78int __must_check class_register(const struct class *class);
79void class_unregister(const struct class *class);
80bool class_is_registered(const struct class *class);
81
82struct class_compat;
83struct class_compat *class_compat_register(const char *name);
84void class_compat_unregister(struct class_compat *cls);
85int class_compat_create_link(struct class_compat *cls, struct device *dev);
86void class_compat_remove_link(struct class_compat *cls, struct device *dev);
87
88void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
89 const struct device *start, const struct device_type *type);
90struct device *class_dev_iter_next(struct class_dev_iter *iter);
91void class_dev_iter_exit(struct class_dev_iter *iter);
92
93int class_for_each_device(const struct class *class, const struct device *start,
94 void *data, device_iter_t fn);
95struct device *class_find_device(const struct class *class, const struct device *start,
96 const void *data, device_match_t match);
97
98/**
99 * class_find_device_by_name - device iterator for locating a particular device
100 * of a specific name.
101 * @class: class type
102 * @name: name of the device to match
103 */
104static inline struct device *class_find_device_by_name(const struct class *class,
105 const char *name)
106{
107 return class_find_device(class, NULL, data: name, match: device_match_name);
108}
109
110/**
111 * class_find_device_by_of_node : device iterator for locating a particular device
112 * matching the of_node.
113 * @class: class type
114 * @np: of_node of the device to match.
115 */
116static inline struct device *class_find_device_by_of_node(const struct class *class,
117 const struct device_node *np)
118{
119 return class_find_device(class, NULL, data: np, match: device_match_of_node);
120}
121
122/**
123 * class_find_device_by_fwnode : device iterator for locating a particular device
124 * matching the fwnode.
125 * @class: class type
126 * @fwnode: fwnode of the device to match.
127 */
128static inline struct device *class_find_device_by_fwnode(const struct class *class,
129 const struct fwnode_handle *fwnode)
130{
131 return class_find_device(class, NULL, data: fwnode, match: device_match_fwnode);
132}
133
134/**
135 * class_find_device_by_devt : device iterator for locating a particular device
136 * matching the device type.
137 * @class: class type
138 * @devt: device type of the device to match.
139 */
140static inline struct device *class_find_device_by_devt(const struct class *class,
141 dev_t devt)
142{
143 return class_find_device(class, NULL, data: &devt, match: device_match_devt);
144}
145
146#ifdef CONFIG_ACPI
147struct acpi_device;
148/**
149 * class_find_device_by_acpi_dev : device iterator for locating a particular
150 * device matching the ACPI_COMPANION device.
151 * @class: class type
152 * @adev: ACPI_COMPANION device to match.
153 */
154static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
155 const struct acpi_device *adev)
156{
157 return class_find_device(class, NULL, data: adev, match: device_match_acpi_dev);
158}
159#else
160static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
161 const void *adev)
162{
163 return NULL;
164}
165#endif
166
167struct class_attribute {
168 struct attribute attr;
169 ssize_t (*show)(const struct class *class, const struct class_attribute *attr,
170 char *buf);
171 ssize_t (*store)(const struct class *class, const struct class_attribute *attr,
172 const char *buf, size_t count);
173};
174
175#define CLASS_ATTR_RW(_name) \
176 struct class_attribute class_attr_##_name = __ATTR_RW(_name)
177#define CLASS_ATTR_RO(_name) \
178 struct class_attribute class_attr_##_name = __ATTR_RO(_name)
179#define CLASS_ATTR_WO(_name) \
180 struct class_attribute class_attr_##_name = __ATTR_WO(_name)
181
182int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr,
183 const void *ns);
184void class_remove_file_ns(const struct class *class, const struct class_attribute *attr,
185 const void *ns);
186
187static inline int __must_check class_create_file(const struct class *class,
188 const struct class_attribute *attr)
189{
190 return class_create_file_ns(class, attr, NULL);
191}
192
193static inline void class_remove_file(const struct class *class,
194 const struct class_attribute *attr)
195{
196 class_remove_file_ns(class, attr, NULL);
197}
198
199/* Simple class attribute that is just a static string */
200struct class_attribute_string {
201 struct class_attribute attr;
202 char *str;
203};
204
205/* Currently read-only only */
206#define _CLASS_ATTR_STRING(_name, _mode, _str) \
207 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
208#define CLASS_ATTR_STRING(_name, _mode, _str) \
209 struct class_attribute_string class_attr_##_name = \
210 _CLASS_ATTR_STRING(_name, _mode, _str)
211
212ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr,
213 char *buf);
214
215struct class_interface {
216 struct list_head node;
217 const struct class *class;
218
219 int (*add_dev) (struct device *dev);
220 void (*remove_dev) (struct device *dev);
221};
222
223int __must_check class_interface_register(struct class_interface *);
224void class_interface_unregister(struct class_interface *);
225
226struct class * __must_check class_create(const char *name);
227void class_destroy(const struct class *cls);
228
229#endif /* _DEVICE_CLASS_H_ */
230

source code of linux/include/linux/device/class.h

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