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 #include <linux/android_kabi.h>
22
23 struct device;
24 struct fwnode_handle;
25
26 /**
27 * struct class - device classes
28 * @name: Name of the class.
29 * @class_groups: Default attributes of this class.
30 * @dev_groups: Default attributes of the devices that belong to the class.
31 * @dev_uevent: Called when a device is added, removed from this class, or a
32 * few other things that generate uevents to add the environment
33 * variables.
34 * @devnode: Callback to provide the devtmpfs.
35 * @class_release: Called to release this class.
36 * @dev_release: Called to release the device.
37 * @shutdown_pre: Called at shut-down time before driver shutdown.
38 * @ns_type: Callbacks so sysfs can detemine namespaces.
39 * @namespace: Namespace of the device belongs to this class.
40 * @get_ownership: Allows class to specify uid/gid of the sysfs directories
41 * for the devices belonging to the class. Usually tied to
42 * device's namespace.
43 * @pm: The default device power management operations of this class.
44 *
45 * A class is a higher-level view of a device that abstracts out low-level
46 * implementation details. Drivers may see a SCSI disk or an ATA disk, but,
47 * at the class level, they are all simply disks. Classes allow user space
48 * to work with devices based on what they do, rather than how they are
49 * connected or how they work.
50 */
51 struct class {
52 const char *name;
53
54 const struct attribute_group **class_groups;
55 const struct attribute_group **dev_groups;
56
57 int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env);
58 char *(*devnode)(const struct device *dev, umode_t *mode);
59
60 void (*class_release)(const struct class *class);
61 void (*dev_release)(struct device *dev);
62
63 int (*shutdown_pre)(struct device *dev);
64
65 const struct kobj_ns_type_operations *ns_type;
66 const void *(*namespace)(const struct device *dev);
67
68 void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid);
69
70 const struct dev_pm_ops *pm;
71
72 ANDROID_KABI_RESERVE(1);
73 ANDROID_KABI_RESERVE(2);
74 ANDROID_KABI_RESERVE(3);
75 ANDROID_KABI_RESERVE(4);
76 };
77
78 struct class_dev_iter {
79 struct klist_iter ki;
80 const struct device_type *type;
81 struct subsys_private *sp;
82 };
83
84 int __must_check class_register(const struct class *class);
85 void class_unregister(const struct class *class);
86 bool class_is_registered(const struct class *class);
87
88 struct class_compat;
89 struct class_compat *class_compat_register(const char *name);
90 void class_compat_unregister(struct class_compat *cls);
91 int class_compat_create_link(struct class_compat *cls, struct device *dev,
92 struct device *device_link);
93 void class_compat_remove_link(struct class_compat *cls, struct device *dev,
94 struct device *device_link);
95
96 void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class,
97 const struct device *start, const struct device_type *type);
98 struct device *class_dev_iter_next(struct class_dev_iter *iter);
99 void class_dev_iter_exit(struct class_dev_iter *iter);
100
101 int class_for_each_device(const struct class *class, const struct device *start, void *data,
102 int (*fn)(struct device *dev, void *data));
103 struct device *class_find_device(const struct class *class, const struct device *start,
104 const void *data, device_match_t match);
105
106 /**
107 * class_find_device_by_name - device iterator for locating a particular device
108 * of a specific name.
109 * @class: class type
110 * @name: name of the device to match
111 */
class_find_device_by_name(const struct class * class,const char * name)112 static inline struct device *class_find_device_by_name(const struct class *class,
113 const char *name)
114 {
115 return class_find_device(class, NULL, name, device_match_name);
116 }
117
118 /**
119 * class_find_device_by_of_node : device iterator for locating a particular device
120 * matching the of_node.
121 * @class: class type
122 * @np: of_node of the device to match.
123 */
class_find_device_by_of_node(const struct class * class,const struct device_node * np)124 static inline struct device *class_find_device_by_of_node(const struct class *class,
125 const struct device_node *np)
126 {
127 return class_find_device(class, NULL, np, device_match_of_node);
128 }
129
130 /**
131 * class_find_device_by_fwnode : device iterator for locating a particular device
132 * matching the fwnode.
133 * @class: class type
134 * @fwnode: fwnode of the device to match.
135 */
class_find_device_by_fwnode(const struct class * class,const struct fwnode_handle * fwnode)136 static inline struct device *class_find_device_by_fwnode(const struct class *class,
137 const struct fwnode_handle *fwnode)
138 {
139 return class_find_device(class, NULL, fwnode, device_match_fwnode);
140 }
141
142 /**
143 * class_find_device_by_devt : device iterator for locating a particular device
144 * matching the device type.
145 * @class: class type
146 * @devt: device type of the device to match.
147 */
class_find_device_by_devt(const struct class * class,dev_t devt)148 static inline struct device *class_find_device_by_devt(const struct class *class,
149 dev_t devt)
150 {
151 return class_find_device(class, NULL, &devt, device_match_devt);
152 }
153
154 #ifdef CONFIG_ACPI
155 struct acpi_device;
156 /**
157 * class_find_device_by_acpi_dev : device iterator for locating a particular
158 * device matching the ACPI_COMPANION device.
159 * @class: class type
160 * @adev: ACPI_COMPANION device to match.
161 */
class_find_device_by_acpi_dev(const struct class * class,const struct acpi_device * adev)162 static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
163 const struct acpi_device *adev)
164 {
165 return class_find_device(class, NULL, adev, device_match_acpi_dev);
166 }
167 #else
class_find_device_by_acpi_dev(const struct class * class,const void * adev)168 static inline struct device *class_find_device_by_acpi_dev(const struct class *class,
169 const void *adev)
170 {
171 return NULL;
172 }
173 #endif
174
175 struct class_attribute {
176 struct attribute attr;
177 ssize_t (*show)(const struct class *class, const struct class_attribute *attr,
178 char *buf);
179 ssize_t (*store)(const struct class *class, const struct class_attribute *attr,
180 const char *buf, size_t count);
181 };
182
183 #define CLASS_ATTR_RW(_name) \
184 struct class_attribute class_attr_##_name = __ATTR_RW(_name)
185 #define CLASS_ATTR_RO(_name) \
186 struct class_attribute class_attr_##_name = __ATTR_RO(_name)
187 #define CLASS_ATTR_WO(_name) \
188 struct class_attribute class_attr_##_name = __ATTR_WO(_name)
189
190 int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr,
191 const void *ns);
192 void class_remove_file_ns(const struct class *class, const struct class_attribute *attr,
193 const void *ns);
194
class_create_file(const struct class * class,const struct class_attribute * attr)195 static inline int __must_check class_create_file(const struct class *class,
196 const struct class_attribute *attr)
197 {
198 return class_create_file_ns(class, attr, NULL);
199 }
200
class_remove_file(const struct class * class,const struct class_attribute * attr)201 static inline void class_remove_file(const struct class *class,
202 const struct class_attribute *attr)
203 {
204 return class_remove_file_ns(class, attr, NULL);
205 }
206
207 /* Simple class attribute that is just a static string */
208 struct class_attribute_string {
209 struct class_attribute attr;
210 char *str;
211 };
212
213 /* Currently read-only only */
214 #define _CLASS_ATTR_STRING(_name, _mode, _str) \
215 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str }
216 #define CLASS_ATTR_STRING(_name, _mode, _str) \
217 struct class_attribute_string class_attr_##_name = \
218 _CLASS_ATTR_STRING(_name, _mode, _str)
219
220 ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr,
221 char *buf);
222
223 struct class_interface {
224 struct list_head node;
225 const struct class *class;
226
227 int (*add_dev) (struct device *dev);
228 void (*remove_dev) (struct device *dev);
229 };
230
231 int __must_check class_interface_register(struct class_interface *);
232 void class_interface_unregister(struct class_interface *);
233
234 struct class * __must_check class_create(const char *name);
235 void class_destroy(const struct class *cls);
236
237 #endif /* _DEVICE_CLASS_H_ */
238