Line data Source code
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 :
22 : struct device;
23 : struct 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 : */
52 : struct 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 :
74 : struct class_dev_iter {
75 : struct klist_iter ki;
76 : const struct device_type *type;
77 : struct subsys_private *sp;
78 : };
79 :
80 : int __must_check class_register(const struct class *class);
81 : void class_unregister(const struct class *class);
82 : bool class_is_registered(const struct class *class);
83 :
84 : struct class_compat;
85 : struct class_compat *class_compat_register(const char *name);
86 : void class_compat_unregister(struct class_compat *cls);
87 : int class_compat_create_link(struct class_compat *cls, struct device *dev,
88 : struct device *device_link);
89 : void class_compat_remove_link(struct class_compat *cls, struct device *dev,
90 : struct device *device_link);
91 :
92 : void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
93 : const struct device *start, const struct device_type *type);
94 : struct device *class_dev_iter_next(struct class_dev_iter *iter);
95 : void class_dev_iter_exit(struct class_dev_iter *iter);
96 :
97 : int class_for_each_device(const struct class *class, const struct device *start, void *data,
98 : int (*fn)(struct device *dev, void *data));
99 : struct 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 : */
108 : static inline struct device *class_find_device_by_name(const struct class *class,
109 : const char *name)
110 : {
111 : return class_find_device(class, NULL, name, 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 : */
120 : static 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, np, 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 : */
132 : static 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, fwnode, 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 : */
144 : static inline struct device *class_find_device_by_devt(const struct class *class,
145 : dev_t devt)
146 : {
147 0 : return class_find_device(class, NULL, &devt, device_match_devt);
148 : }
149 :
150 : #ifdef CONFIG_ACPI
151 : struct 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 : */
158 : static 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, adev, device_match_acpi_dev);
162 : }
163 : #else
164 : static 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 :
171 : struct 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 :
186 : int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr,
187 : const void *ns);
188 : void class_remove_file_ns(const struct class *class, const struct class_attribute *attr,
189 : const void *ns);
190 :
191 : static inline int __must_check class_create_file(const struct class *class,
192 : const struct class_attribute *attr)
193 : {
194 1 : return class_create_file_ns(class, attr, NULL);
195 : }
196 :
197 : static inline void class_remove_file(const struct class *class,
198 : const struct class_attribute *attr)
199 : {
200 0 : return class_remove_file_ns(class, attr, NULL);
201 : }
202 :
203 : /* Simple class attribute that is just a static string */
204 : struct 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 :
216 : ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr,
217 : char *buf);
218 :
219 : struct 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 :
227 : int __must_check class_interface_register(struct class_interface *);
228 : void class_interface_unregister(struct class_interface *);
229 :
230 : struct class * __must_check class_create(const char *name);
231 : void class_destroy(const struct class *cls);
232 :
233 : #endif /* _DEVICE_CLASS_H_ */
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