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 * 44 * A class is a higher-level view of a device that abstracts out low-level 45 * implementation details. Drivers may see a SCSI disk or an ATA disk, but, 46 * at the class level, they are all simply disks. Classes allow user space 47 * to work with devices based on what they do, rather than how they are 48 * connected or how they work. 49 */ 50 struct class { 51 const char *name; 52 53 const struct attribute_group **class_groups; 54 const struct attribute_group **dev_groups; 55 56 int (*dev_uevent)(const struct device *dev, struct kobj_uevent_env *env); 57 char *(*devnode)(const struct device *dev, umode_t *mode); 58 59 void (*class_release)(const struct class *class); 60 void (*dev_release)(struct device *dev); 61 62 int (*shutdown_pre)(struct device *dev); 63 64 const struct kobj_ns_type_operations *ns_type; 65 const void *(*namespace)(const struct device *dev); 66 67 void (*get_ownership)(const struct device *dev, kuid_t *uid, kgid_t *gid); 68 69 const struct dev_pm_ops *pm; 70 }; 71 72 struct class_dev_iter { 73 struct klist_iter ki; 74 const struct device_type *type; 75 struct subsys_private *sp; 76 }; 77 78 int __must_check class_register(const struct class *class); 79 void class_unregister(const struct class *class); 80 bool class_is_registered(const struct class *class); 81 82 struct class_compat; 83 struct class_compat *class_compat_register(const char *name); 84 void class_compat_unregister(struct class_compat *cls); 85 int class_compat_create_link(struct class_compat *cls, struct device *dev); 86 void class_compat_remove_link(struct class_compat *cls, struct device *dev); 87 88 void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, 89 const struct device *start, const struct device_type *type); 90 struct device *class_dev_iter_next(struct class_dev_iter *iter); 91 void class_dev_iter_exit(struct class_dev_iter *iter); 92 93 int class_for_each_device(const struct class *class, const struct device *start, 94 void *data, device_iter_t fn); 95 struct device *class_find_device(const struct class *class, const struct device *start, 96 const void *data, device_match_t match); 97 98 /** 99 * class_find_device_by_name - device iterator for locating a particular device 100 * of a specific name. 101 * @class: class type 102 * @name: name of the device to match 103 */ 104 static inline struct device *class_find_device_by_name(const struct class *class, 105 const char *name) 106 { 107 return class_find_device(class, NULL, name, device_match_name); 108 } 109 110 /** 111 * class_find_device_by_of_node : device iterator for locating a particular device 112 * matching the of_node. 113 * @class: class type 114 * @np: of_node of the device to match. 115 */ 116 static inline struct device *class_find_device_by_of_node(const struct class *class, 117 const struct device_node *np) 118 { 119 return class_find_device(class, NULL, np, device_match_of_node); 120 } 121 122 /** 123 * class_find_device_by_fwnode : device iterator for locating a particular device 124 * matching the fwnode. 125 * @class: class type 126 * @fwnode: fwnode of the device to match. 127 */ 128 static inline struct device *class_find_device_by_fwnode(const struct class *class, 129 const struct fwnode_handle *fwnode) 130 { 131 return class_find_device(class, NULL, fwnode, device_match_fwnode); 132 } 133 134 /** 135 * class_find_device_by_devt : device iterator for locating a particular device 136 * matching the device type. 137 * @class: class type 138 * @devt: device type of the device to match. 139 */ 140 static inline struct device *class_find_device_by_devt(const struct class *class, 141 dev_t devt) 142 { 143 return class_find_device(class, NULL, &devt, device_match_devt); 144 } 145 146 #ifdef CONFIG_ACPI 147 struct acpi_device; 148 /** 149 * class_find_device_by_acpi_dev : device iterator for locating a particular 150 * device matching the ACPI_COMPANION device. 151 * @class: class type 152 * @adev: ACPI_COMPANION device to match. 153 */ 154 static inline struct device *class_find_device_by_acpi_dev(const struct class *class, 155 const struct acpi_device *adev) 156 { 157 return class_find_device(class, NULL, adev, device_match_acpi_dev); 158 } 159 #else 160 static inline struct device *class_find_device_by_acpi_dev(const struct class *class, 161 const void *adev) 162 { 163 return NULL; 164 } 165 #endif 166 167 struct class_attribute { 168 struct attribute attr; 169 ssize_t (*show)(const struct class *class, const struct class_attribute *attr, 170 char *buf); 171 ssize_t (*store)(const struct class *class, const struct class_attribute *attr, 172 const char *buf, size_t count); 173 }; 174 175 #define CLASS_ATTR_RW(_name) \ 176 struct class_attribute class_attr_##_name = __ATTR_RW(_name) 177 #define CLASS_ATTR_RO(_name) \ 178 struct class_attribute class_attr_##_name = __ATTR_RO(_name) 179 #define CLASS_ATTR_WO(_name) \ 180 struct class_attribute class_attr_##_name = __ATTR_WO(_name) 181 182 int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr, 183 const void *ns); 184 void class_remove_file_ns(const struct class *class, const struct class_attribute *attr, 185 const void *ns); 186 187 static inline int __must_check class_create_file(const struct class *class, 188 const struct class_attribute *attr) 189 { 190 return class_create_file_ns(class, attr, NULL); 191 } 192 193 static inline void class_remove_file(const struct class *class, 194 const struct class_attribute *attr) 195 { 196 return class_remove_file_ns(class, attr, NULL); 197 } 198 199 /* Simple class attribute that is just a static string */ 200 struct class_attribute_string { 201 struct class_attribute attr; 202 char *str; 203 }; 204 205 /* Currently read-only only */ 206 #define _CLASS_ATTR_STRING(_name, _mode, _str) \ 207 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str } 208 #define CLASS_ATTR_STRING(_name, _mode, _str) \ 209 struct class_attribute_string class_attr_##_name = \ 210 _CLASS_ATTR_STRING(_name, _mode, _str) 211 212 ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr, 213 char *buf); 214 215 struct class_interface { 216 struct list_head node; 217 const struct class *class; 218 219 int (*add_dev) (struct device *dev); 220 void (*remove_dev) (struct device *dev); 221 }; 222 223 int __must_check class_interface_register(struct class_interface *); 224 void class_interface_unregister(struct class_interface *); 225 226 struct class * __must_check class_create(const char *name); 227 void class_destroy(const struct class *cls); 228 229 #endif /* _DEVICE_CLASS_H_ */ 230