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 : * @owner: The module owner.
29 : * @class_groups: Default attributes of this class.
30 : * @dev_groups: Default attributes of the devices that belong to the class.
31 : * @dev_kobj: The kobject that represents this class and links it into the hierarchy.
32 : * @dev_uevent: Called when a device is added, removed from this class, or a
33 : * few other things that generate uevents to add the environment
34 : * variables.
35 : * @devnode: Callback to provide the devtmpfs.
36 : * @class_release: Called to release this class.
37 : * @dev_release: Called to release the device.
38 : * @shutdown_pre: Called at shut-down time before driver shutdown.
39 : * @ns_type: Callbacks so sysfs can detemine namespaces.
40 : * @namespace: Namespace of the device belongs to this class.
41 : * @get_ownership: Allows class to specify uid/gid of the sysfs directories
42 : * for the devices belonging to the class. Usually tied to
43 : * device's namespace.
44 : * @pm: The default device power management operations of this class.
45 : * @p: The private data of the driver core, no one other than the
46 : * driver core can touch this.
47 : *
48 : * A class is a higher-level view of a device that abstracts out low-level
49 : * implementation details. Drivers may see a SCSI disk or an ATA disk, but,
50 : * at the class level, they are all simply disks. Classes allow user space
51 : * to work with devices based on what they do, rather than how they are
52 : * connected or how they work.
53 : */
54 : struct class {
55 : const char *name;
56 : struct module *owner;
57 :
58 : const struct attribute_group **class_groups;
59 : const struct attribute_group **dev_groups;
60 : struct kobject *dev_kobj;
61 :
62 : int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env);
63 : char *(*devnode)(const struct device *dev, umode_t *mode);
64 :
65 : void (*class_release)(struct class *class);
66 : void (*dev_release)(struct device *dev);
67 :
68 : int (*shutdown_pre)(struct device *dev);
69 :
70 : const struct kobj_ns_type_operations *ns_type;
71 : const void *(*namespace)(const struct device *dev);
72 :
73 : void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid);
74 :
75 : const struct dev_pm_ops *pm;
76 :
77 : struct subsys_private *p;
78 : };
79 :
80 : struct class_dev_iter {
81 : struct klist_iter ki;
82 : const struct device_type *type;
83 : };
84 :
85 : extern struct kobject *sysfs_dev_block_kobj;
86 : extern struct kobject *sysfs_dev_char_kobj;
87 : extern int __must_check __class_register(struct class *class,
88 : struct lock_class_key *key);
89 : extern void class_unregister(struct class *class);
90 :
91 : /* This is a #define to keep the compiler from merging different
92 : * instances of the __key variable */
93 : #define class_register(class) \
94 : ({ \
95 : static struct lock_class_key __key; \
96 : __class_register(class, &__key); \
97 : })
98 :
99 : struct class_compat;
100 : struct class_compat *class_compat_register(const char *name);
101 : void class_compat_unregister(struct class_compat *cls);
102 : int class_compat_create_link(struct class_compat *cls, struct device *dev,
103 : struct device *device_link);
104 : void class_compat_remove_link(struct class_compat *cls, struct device *dev,
105 : struct device *device_link);
106 :
107 : extern void class_dev_iter_init(struct class_dev_iter *iter,
108 : struct class *class,
109 : struct device *start,
110 : const struct device_type *type);
111 : extern struct device *class_dev_iter_next(struct class_dev_iter *iter);
112 : extern void class_dev_iter_exit(struct class_dev_iter *iter);
113 :
114 : extern int class_for_each_device(struct class *class, struct device *start,
115 : void *data,
116 : int (*fn)(struct device *dev, void *data));
117 : extern struct device *class_find_device(struct class *class,
118 : struct device *start, const void *data,
119 : int (*match)(struct device *, const void *));
120 :
121 : /**
122 : * class_find_device_by_name - device iterator for locating a particular device
123 : * of a specific name.
124 : * @class: class type
125 : * @name: name of the device to match
126 : */
127 : static inline struct device *class_find_device_by_name(struct class *class,
128 : const char *name)
129 : {
130 : return class_find_device(class, NULL, name, device_match_name);
131 : }
132 :
133 : /**
134 : * class_find_device_by_of_node : device iterator for locating a particular device
135 : * matching the of_node.
136 : * @class: class type
137 : * @np: of_node of the device to match.
138 : */
139 : static inline struct device *
140 : class_find_device_by_of_node(struct class *class, const struct device_node *np)
141 : {
142 : return class_find_device(class, NULL, np, device_match_of_node);
143 : }
144 :
145 : /**
146 : * class_find_device_by_fwnode : device iterator for locating a particular device
147 : * matching the fwnode.
148 : * @class: class type
149 : * @fwnode: fwnode of the device to match.
150 : */
151 : static inline struct device *
152 : class_find_device_by_fwnode(struct class *class,
153 : const struct fwnode_handle *fwnode)
154 : {
155 : return class_find_device(class, NULL, fwnode, device_match_fwnode);
156 : }
157 :
158 : /**
159 : * class_find_device_by_devt : device iterator for locating a particular device
160 : * matching the device type.
161 : * @class: class type
162 : * @devt: device type of the device to match.
163 : */
164 : static inline struct device *class_find_device_by_devt(struct class *class,
165 : dev_t devt)
166 : {
167 0 : return class_find_device(class, NULL, &devt, device_match_devt);
168 : }
169 :
170 : #ifdef CONFIG_ACPI
171 : struct acpi_device;
172 : /**
173 : * class_find_device_by_acpi_dev : device iterator for locating a particular
174 : * device matching the ACPI_COMPANION device.
175 : * @class: class type
176 : * @adev: ACPI_COMPANION device to match.
177 : */
178 : static inline struct device *
179 : class_find_device_by_acpi_dev(struct class *class, const struct acpi_device *adev)
180 : {
181 : return class_find_device(class, NULL, adev, device_match_acpi_dev);
182 : }
183 : #else
184 : static inline struct device *
185 : class_find_device_by_acpi_dev(struct class *class, const void *adev)
186 : {
187 : return NULL;
188 : }
189 : #endif
190 :
191 : struct class_attribute {
192 : struct attribute attr;
193 : ssize_t (*show)(struct class *class, struct class_attribute *attr,
194 : char *buf);
195 : ssize_t (*store)(struct class *class, struct class_attribute *attr,
196 : const char *buf, size_t count);
197 : };
198 :
199 : #define CLASS_ATTR_RW(_name) \
200 : struct class_attribute class_attr_##_name = __ATTR_RW(_name)
201 : #define CLASS_ATTR_RO(_name) \
202 : struct class_attribute class_attr_##_name = __ATTR_RO(_name)
203 : #define CLASS_ATTR_WO(_name) \
204 : struct class_attribute class_attr_##_name = __ATTR_WO(_name)
205 :
206 : extern int __must_check class_create_file_ns(struct class *class,
207 : const struct class_attribute *attr,
208 : const void *ns);
209 : extern void class_remove_file_ns(struct class *class,
210 : const struct class_attribute *attr,
211 : const void *ns);
212 :
213 : static inline int __must_check class_create_file(struct class *class,
214 : const struct class_attribute *attr)
215 : {
216 1 : return class_create_file_ns(class, attr, NULL);
217 : }
218 :
219 : static inline void class_remove_file(struct class *class,
220 : const struct class_attribute *attr)
221 : {
222 0 : return class_remove_file_ns(class, attr, NULL);
223 : }
224 :
225 : /* Simple class attribute that is just a static string */
226 : struct class_attribute_string {
227 : struct class_attribute attr;
228 : char *str;
229 : };
230 :
231 : /* Currently read-only only */
232 : #define _CLASS_ATTR_STRING(_name, _mode, _str) \
233 : { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
234 : #define CLASS_ATTR_STRING(_name, _mode, _str) \
235 : struct class_attribute_string class_attr_##_name = \
236 : _CLASS_ATTR_STRING(_name, _mode, _str)
237 :
238 : extern ssize_t show_class_attr_string(struct class *class, struct class_attribute *attr,
239 : char *buf);
240 :
241 : struct class_interface {
242 : struct list_head node;
243 : struct class *class;
244 :
245 : int (*add_dev) (struct device *, struct class_interface *);
246 : void (*remove_dev) (struct device *, struct class_interface *);
247 : };
248 :
249 : extern int __must_check class_interface_register(struct class_interface *);
250 : extern void class_interface_unregister(struct class_interface *);
251 :
252 : extern struct class * __must_check __class_create(struct module *owner,
253 : const char *name,
254 : struct lock_class_key *key);
255 : extern void class_destroy(struct class *cls);
256 :
257 : /* This is a #define to keep the compiler from merging different
258 : * instances of the __key variable */
259 :
260 : /**
261 : * class_create - create a struct class structure
262 : * @owner: pointer to the module that is to "own" this struct class
263 : * @name: pointer to a string for the name of this class.
264 : *
265 : * This is used to create a struct class pointer that can then be used
266 : * in calls to device_create().
267 : *
268 : * Returns &struct class pointer on success, or ERR_PTR() on error.
269 : *
270 : * Note, the pointer created here is to be destroyed when finished by
271 : * making a call to class_destroy().
272 : */
273 : #define class_create(owner, name) \
274 : ({ \
275 : static struct lock_class_key __key; \
276 : __class_create(owner, name, &__key); \
277 : })
278 :
279 :
280 : #endif /* _DEVICE_CLASS_H_ */
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