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 85 int __must_check class_register(struct class *class); 86 void class_unregister(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, int (*match)(struct device *, const void *)); 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 */ 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 */ 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 */ 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 */ 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 */ 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 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); 194 195 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 } 200 201 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 struct class *class; 226 227 int (*add_dev) (struct device *, struct class_interface *); 228 void (*remove_dev) (struct device *, struct class_interface *); 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