xref: /openbmc/linux/include/linux/device/class.h (revision ddaf098e)
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  */
class_find_device_by_name(const struct class * class,const char * name)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  */
class_find_device_by_of_node(const struct class * class,const struct device_node * np)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  */
class_find_device_by_fwnode(const struct class * class,const struct fwnode_handle * fwnode)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  */
class_find_device_by_devt(const struct class * class,dev_t devt)144 static inline struct device *class_find_device_by_devt(const struct class *class,
145 						       dev_t devt)
146 {
147 	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  */
class_find_device_by_acpi_dev(const struct class * class,const struct acpi_device * adev)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
class_find_device_by_acpi_dev(const struct class * class,const void * adev)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 
class_create_file(const struct class * class,const struct class_attribute * attr)191 static 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 
class_remove_file(const struct class * class,const struct class_attribute * attr)197 static 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 */
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_ */
234