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 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 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 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_ */ 281