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 <[email protected]> 6 * Copyright (c) 2004-2009 Greg Kroah-Hartman <[email protected]> 7 * Copyright (c) 2008-2009 Novell Inc. 8 * Copyright (c) 2012-2019 Greg Kroah-Hartman <[email protected]> 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_kobj: The kobject that represents this class and links it into the hierarchy. 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 * @p: The private data of the driver core, no one other than the 45 * driver core can touch this. 46 * 47 * A class is a higher-level view of a device that abstracts out low-level 48 * implementation details. Drivers may see a SCSI disk or an ATA disk, but, 49 * at the class level, they are all simply disks. Classes allow user space 50 * to work with devices based on what they do, rather than how they are 51 * connected or how they work. 52 */ 53 struct class { 54 const char *name; 55 56 const struct attribute_group **class_groups; 57 const struct attribute_group **dev_groups; 58 struct kobject *dev_kobj; 59 60 int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env); 61 char *(*devnode)(const struct device *dev, umode_t *mode); 62 63 void (*class_release)(struct class *class); 64 void (*dev_release)(struct device *dev); 65 66 int (*shutdown_pre)(struct device *dev); 67 68 const struct kobj_ns_type_operations *ns_type; 69 const void *(*namespace)(const struct device *dev); 70 71 void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid); 72 73 const struct dev_pm_ops *pm; 74 75 struct subsys_private *p; 76 }; 77 78 struct class_dev_iter { 79 struct klist_iter ki; 80 const struct device_type *type; 81 }; 82 83 extern struct kobject *sysfs_dev_block_kobj; 84 extern struct kobject *sysfs_dev_char_kobj; 85 extern int __must_check __class_register(struct class *class, 86 struct lock_class_key *key); 87 extern void class_unregister(struct class *class); 88 89 /* This is a #define to keep the compiler from merging different 90 * instances of the __key variable */ 91 #define class_register(class) \ 92 ({ \ 93 static struct lock_class_key __key; \ 94 __class_register(class, &__key); \ 95 }) 96 97 struct class_compat; 98 struct class_compat *class_compat_register(const char *name); 99 void class_compat_unregister(struct class_compat *cls); 100 int class_compat_create_link(struct class_compat *cls, struct device *dev, 101 struct device *device_link); 102 void class_compat_remove_link(struct class_compat *cls, struct device *dev, 103 struct device *device_link); 104 105 extern void class_dev_iter_init(struct class_dev_iter *iter, 106 const struct class *class, 107 const struct device *start, 108 const struct device_type *type); 109 extern struct device *class_dev_iter_next(struct class_dev_iter *iter); 110 extern void class_dev_iter_exit(struct class_dev_iter *iter); 111 112 extern int class_for_each_device(const struct class *class, const struct device *start, 113 void *data, 114 int (*fn)(struct device *dev, void *data)); 115 extern struct device *class_find_device(struct class *class, 116 struct device *start, const void *data, 117 int (*match)(struct device *, const void *)); 118 119 /** 120 * class_find_device_by_name - device iterator for locating a particular device 121 * of a specific name. 122 * @class: class type 123 * @name: name of the device to match 124 */ 125 static inline struct device *class_find_device_by_name(struct class *class, 126 const char *name) 127 { 128 return class_find_device(class, NULL, name, device_match_name); 129 } 130 131 /** 132 * class_find_device_by_of_node : device iterator for locating a particular device 133 * matching the of_node. 134 * @class: class type 135 * @np: of_node of the device to match. 136 */ 137 static inline struct device * 138 class_find_device_by_of_node(struct class *class, const struct device_node *np) 139 { 140 return class_find_device(class, NULL, np, device_match_of_node); 141 } 142 143 /** 144 * class_find_device_by_fwnode : device iterator for locating a particular device 145 * matching the fwnode. 146 * @class: class type 147 * @fwnode: fwnode of the device to match. 148 */ 149 static inline struct device * 150 class_find_device_by_fwnode(struct class *class, 151 const struct fwnode_handle *fwnode) 152 { 153 return class_find_device(class, NULL, fwnode, device_match_fwnode); 154 } 155 156 /** 157 * class_find_device_by_devt : device iterator for locating a particular device 158 * matching the device type. 159 * @class: class type 160 * @devt: device type of the device to match. 161 */ 162 static inline struct device *class_find_device_by_devt(struct class *class, 163 dev_t devt) 164 { 165 return class_find_device(class, NULL, &devt, device_match_devt); 166 } 167 168 #ifdef CONFIG_ACPI 169 struct acpi_device; 170 /** 171 * class_find_device_by_acpi_dev : device iterator for locating a particular 172 * device matching the ACPI_COMPANION device. 173 * @class: class type 174 * @adev: ACPI_COMPANION device to match. 175 */ 176 static inline struct device * 177 class_find_device_by_acpi_dev(struct class *class, const struct acpi_device *adev) 178 { 179 return class_find_device(class, NULL, adev, device_match_acpi_dev); 180 } 181 #else 182 static inline struct device * 183 class_find_device_by_acpi_dev(struct class *class, const void *adev) 184 { 185 return NULL; 186 } 187 #endif 188 189 struct class_attribute { 190 struct attribute attr; 191 ssize_t (*show)(struct class *class, struct class_attribute *attr, 192 char *buf); 193 ssize_t (*store)(struct class *class, struct class_attribute *attr, 194 const char *buf, size_t count); 195 }; 196 197 #define CLASS_ATTR_RW(_name) \ 198 struct class_attribute class_attr_##_name = __ATTR_RW(_name) 199 #define CLASS_ATTR_RO(_name) \ 200 struct class_attribute class_attr_##_name = __ATTR_RO(_name) 201 #define CLASS_ATTR_WO(_name) \ 202 struct class_attribute class_attr_##_name = __ATTR_WO(_name) 203 204 extern int __must_check class_create_file_ns(struct class *class, 205 const struct class_attribute *attr, 206 const void *ns); 207 extern void class_remove_file_ns(struct class *class, 208 const struct class_attribute *attr, 209 const void *ns); 210 211 static inline int __must_check class_create_file(struct class *class, 212 const struct class_attribute *attr) 213 { 214 return class_create_file_ns(class, attr, NULL); 215 } 216 217 static inline void class_remove_file(struct class *class, 218 const struct class_attribute *attr) 219 { 220 return class_remove_file_ns(class, attr, NULL); 221 } 222 223 /* Simple class attribute that is just a static string */ 224 struct class_attribute_string { 225 struct class_attribute attr; 226 char *str; 227 }; 228 229 /* Currently read-only only */ 230 #define _CLASS_ATTR_STRING(_name, _mode, _str) \ 231 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str } 232 #define CLASS_ATTR_STRING(_name, _mode, _str) \ 233 struct class_attribute_string class_attr_##_name = \ 234 _CLASS_ATTR_STRING(_name, _mode, _str) 235 236 extern ssize_t show_class_attr_string(struct class *class, struct class_attribute *attr, 237 char *buf); 238 239 struct class_interface { 240 struct list_head node; 241 struct class *class; 242 243 int (*add_dev) (struct device *, struct class_interface *); 244 void (*remove_dev) (struct device *, struct class_interface *); 245 }; 246 247 extern int __must_check class_interface_register(struct class_interface *); 248 extern void class_interface_unregister(struct class_interface *); 249 250 extern struct class * __must_check __class_create(const char *name, 251 struct lock_class_key *key); 252 extern void class_destroy(struct class *cls); 253 254 /* This is a #define to keep the compiler from merging different 255 * instances of the __key variable */ 256 257 /** 258 * class_create - create a struct class structure 259 * @name: pointer to a string for the name of this class. 260 * 261 * This is used to create a struct class pointer that can then be used 262 * in calls to device_create(). 263 * 264 * Returns &struct class pointer on success, or ERR_PTR() on error. 265 * 266 * Note, the pointer created here is to be destroyed when finished by 267 * making a call to class_destroy(). 268 */ 269 #define class_create(name) \ 270 ({ \ 271 static struct lock_class_key __key; \ 272 __class_create(name, &__key); \ 273 }) 274 275 276 #endif /* _DEVICE_CLASS_H_ */ 277