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 */ 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 */ 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 */ 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 */ 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 */ 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 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); 190 191 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 } 196 197 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