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,
86 struct device *device_link);
87void class_compat_remove_link(struct class_compat *cls, struct device *dev,
88 struct device *device_link);
89
90void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
91 const struct device *start, const struct device_type *type);
92struct device *class_dev_iter_next(struct class_dev_iter *iter);
93void class_dev_iter_exit(struct class_dev_iter *iter);
94
95int class_for_each_device(const struct class *class, const struct device *start, void *data,
96 int (*fn)(struct device *dev, void *data));
97struct device *class_find_device(const struct class *class, const struct device *start,
98 const void *data, int (*match)(struct device *, const void *));
99
100/**
101 * class_find_device_by_name - device iterator for locating a particular device
102 * of a specific name.
103 * @class: class type
104 * @name: name of the device to match
105 */
106static inline struct device *class_find_device_by_name(const struct class *class,
107 const char *name)
108{
109 return class_find_device(class, NULL, data: name, match: device_match_name);
110}
111
112/**
113 * class_find_device_by_of_node : device iterator for locating a particular device
114 * matching the of_node.
115 * @class: class type
116 * @np: of_node of the device to match.
117 */
118static inline struct device *class_find_device_by_of_node(const struct class *class,
119 const struct device_node *np)
120{
121 return class_find_device(class, NULL, data: np, match: device_match_of_node);
122}
123
124/**
125 * class_find_device_by_fwnode : device iterator for locating a particular device
126 * matching the fwnode.
127 * @class: class type
128 * @fwnode: fwnode of the device to match.
129 */
130static inline struct device *class_find_device_by_fwnode(const struct class *class,
131 const struct fwnode_handle *fwnode)
132{
133 return class_find_device(class, NULL, data: fwnode, match: device_match_fwnode);
134}
135
136/**
137 * class_find_device_by_devt : device iterator for locating a particular device
138 * matching the device type.
139 * @class: class type
140 * @devt: device type of the device to match.
141 */
142static inline struct device *class_find_device_by_devt(const struct class *class,
143 dev_t devt)
144{
145 return class_find_device(class, NULL, data: &devt, match: device_match_devt);
146}
147
148#ifdef CONFIG_ACPI
149struct acpi_device;
150/**
151 * class_find_device_by_acpi_dev : device iterator for locating a particular
152 * device matching the ACPI_COMPANION device.
153 * @class: class type
154 * @adev: ACPI_COMPANION device to match.
155 */
156static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
157 const struct acpi_device *adev)
158{
159 return class_find_device(class, NULL, data: adev, match: device_match_acpi_dev);
160}
161#else
162static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
163 const void *adev)
164{
165 return NULL;
166}
167#endif
168
169struct class_attribute {
170 struct attribute attr;
171 ssize_t (*show)(const struct class *class, const struct class_attribute *attr,
172 char *buf);
173 ssize_t (*store)(const struct class *class, const struct class_attribute *attr,
174 const char *buf, size_t count);
175};
176
177#define CLASS_ATTR_RW(_name) \
178 struct class_attribute class_attr_##_name = __ATTR_RW(_name)
179#define CLASS_ATTR_RO(_name) \
180 struct class_attribute class_attr_##_name = __ATTR_RO(_name)
181#define CLASS_ATTR_WO(_name) \
182 struct class_attribute class_attr_##_name = __ATTR_WO(_name)
183
184int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr,
185 const void *ns);
186void class_remove_file_ns(const struct class *class, const struct class_attribute *attr,
187 const void *ns);
188
189static inline int __must_check class_create_file(const struct class *class,
190 const struct class_attribute *attr)
191{
192 return class_create_file_ns(class, attr, NULL);
193}
194
195static inline void class_remove_file(const struct class *class,
196 const struct class_attribute *attr)
197{
198 return class_remove_file_ns(class, attr, NULL);
199}
200
201/* Simple class attribute that is just a static string */
202struct class_attribute_string {
203 struct class_attribute attr;
204 char *str;
205};
206
207/* Currently read-only only */
208#define _CLASS_ATTR_STRING(_name, _mode, _str) \
209 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
210#define CLASS_ATTR_STRING(_name, _mode, _str) \
211 struct class_attribute_string class_attr_##_name = \
212 _CLASS_ATTR_STRING(_name, _mode, _str)
213
214ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr,
215 char *buf);
216
217struct class_interface {
218 struct list_head node;
219 const struct class *class;
220
221 int (*add_dev) (struct device *dev);
222 void (*remove_dev) (struct device *dev);
223};
224
225int __must_check class_interface_register(struct class_interface *);
226void class_interface_unregister(struct class_interface *);
227
228struct class * __must_check class_create(const char *name);
229void class_destroy(const struct class *cls);
230
231#endif /* _DEVICE_CLASS_H_ */
232

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