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 * @p: The private data of the driver core, no one other than the
44 * driver core can touch this.
45 *
46 * A class is a higher-level view of a device that abstracts out low-level
47 * implementation details. Drivers may see a SCSI disk or an ATA disk, but,
48 * at the class level, they are all simply disks. Classes allow user space
49 * to work with devices based on what they do, rather than how they are
50 * connected or how they work.
51 */
52struct class {
53 const char *name;
54
55 const struct attribute_group **class_groups;
56 const struct attribute_group **dev_groups;
57
58 int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env);
59 char *(*devnode)(const struct device *dev, umode_t *mode);
60
61 void (*class_release)(const struct class *class);
62 void (*dev_release)(struct device *dev);
63
64 int (*shutdown_pre)(struct device *dev);
65
66 const struct kobj_ns_type_operations *ns_type;
67 const void *(*namespace)(const struct device *dev);
68
69 void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid);
70
71 const struct dev_pm_ops *pm;
72};
73
74struct class_dev_iter {
75 struct klist_iter ki;
76 const struct device_type *type;
77 struct subsys_private *sp;
78};
79
80int __must_check class_register(const struct class *class);
81void class_unregister(const struct class *class);
82bool class_is_registered(const struct class *class);
83
84struct class_compat;
85struct class_compat *class_compat_register(const char *name);
86void class_compat_unregister(struct class_compat *cls);
87int class_compat_create_link(struct class_compat *cls, struct device *dev,
88 struct device *device_link);
89void class_compat_remove_link(struct class_compat *cls, struct device *dev,
90 struct device *device_link);
91
92void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
93 const struct device *start, const struct device_type *type);
94struct device *class_dev_iter_next(struct class_dev_iter *iter);
95void class_dev_iter_exit(struct class_dev_iter *iter);
96
97int class_for_each_device(const struct class *class, const struct device *start, void *data,
98 int (*fn)(struct device *dev, void *data));
99struct device *class_find_device(const struct class *class, const struct device *start,
100 const void *data, int (*match)(struct device *, const void *));
101
102/**
103 * class_find_device_by_name - device iterator for locating a particular device
104 * of a specific name.
105 * @class: class type
106 * @name: name of the device to match
107 */
108static inline struct device *class_find_device_by_name(const struct class *class,
109 const char *name)
110{
111 return class_find_device(class, NULL, data: name, match: device_match_name);
112}
113
114/**
115 * class_find_device_by_of_node : device iterator for locating a particular device
116 * matching the of_node.
117 * @class: class type
118 * @np: of_node of the device to match.
119 */
120static inline struct device *class_find_device_by_of_node(const struct class *class,
121 const struct device_node *np)
122{
123 return class_find_device(class, NULL, data: np, match: device_match_of_node);
124}
125
126/**
127 * class_find_device_by_fwnode : device iterator for locating a particular device
128 * matching the fwnode.
129 * @class: class type
130 * @fwnode: fwnode of the device to match.
131 */
132static inline struct device *class_find_device_by_fwnode(const struct class *class,
133 const struct fwnode_handle *fwnode)
134{
135 return class_find_device(class, NULL, data: fwnode, match: device_match_fwnode);
136}
137
138/**
139 * class_find_device_by_devt : device iterator for locating a particular device
140 * matching the device type.
141 * @class: class type
142 * @devt: device type of the device to match.
143 */
144static inline struct device *class_find_device_by_devt(const struct class *class,
145 dev_t devt)
146{
147 return class_find_device(class, NULL, data: &devt, match: device_match_devt);
148}
149
150#ifdef CONFIG_ACPI
151struct acpi_device;
152/**
153 * class_find_device_by_acpi_dev : device iterator for locating a particular
154 * device matching the ACPI_COMPANION device.
155 * @class: class type
156 * @adev: ACPI_COMPANION device to match.
157 */
158static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
159 const struct acpi_device *adev)
160{
161 return class_find_device(class, NULL, data: adev, match: device_match_acpi_dev);
162}
163#else
164static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
165 const void *adev)
166{
167 return NULL;
168}
169#endif
170
171struct class_attribute {
172 struct attribute attr;
173 ssize_t (*show)(const struct class *class, const struct class_attribute *attr,
174 char *buf);
175 ssize_t (*store)(const struct class *class, const struct class_attribute *attr,
176 const char *buf, size_t count);
177};
178
179#define CLASS_ATTR_RW(_name) \
180 struct class_attribute class_attr_##_name = __ATTR_RW(_name)
181#define CLASS_ATTR_RO(_name) \
182 struct class_attribute class_attr_##_name = __ATTR_RO(_name)
183#define CLASS_ATTR_WO(_name) \
184 struct class_attribute class_attr_##_name = __ATTR_WO(_name)
185
186int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr,
187 const void *ns);
188void class_remove_file_ns(const struct class *class, const struct class_attribute *attr,
189 const void *ns);
190
191static inline int __must_check class_create_file(const struct class *class,
192 const struct class_attribute *attr)
193{
194 return class_create_file_ns(class, attr, NULL);
195}
196
197static inline void class_remove_file(const struct class *class,
198 const struct class_attribute *attr)
199{
200 return class_remove_file_ns(class, attr, NULL);
201}
202
203/* Simple class attribute that is just a static string */
204struct class_attribute_string {
205 struct class_attribute attr;
206 char *str;
207};
208
209/* Currently read-only only */
210#define _CLASS_ATTR_STRING(_name, _mode, _str) \
211 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
212#define CLASS_ATTR_STRING(_name, _mode, _str) \
213 struct class_attribute_string class_attr_##_name = \
214 _CLASS_ATTR_STRING(_name, _mode, _str)
215
216ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr,
217 char *buf);
218
219struct class_interface {
220 struct list_head node;
221 const struct class *class;
222
223 int (*add_dev) (struct device *dev);
224 void (*remove_dev) (struct device *dev);
225};
226
227int __must_check class_interface_register(struct class_interface *);
228void class_interface_unregister(struct class_interface *);
229
230struct class * __must_check class_create(const char *name);
231void class_destroy(const struct class *cls);
232
233#endif /* _DEVICE_CLASS_H_ */
234

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