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 }; 78 79 int __must_check class_register(const struct class *class); 80 void class_unregister(const struct class *class); 81 bool class_is_registered(const struct class *class); 82 83 struct class_compat; 84 struct class_compat *class_compat_register(const char *name); 85 void class_compat_unregister(struct class_compat *cls); 86 int class_compat_create_link(struct class_compat *cls, struct device *dev, 87 struct device *device_link); 88 void class_compat_remove_link(struct class_compat *cls, struct device *dev, 89 struct device *device_link); 90 91 void class_dev_iter_init(struct class_dev_iter *iter, const struct class *class, 92 const struct device *start, const struct device_type *type); 93 struct device *class_dev_iter_next(struct class_dev_iter *iter); 94 void class_dev_iter_exit(struct class_dev_iter *iter); 95 96 int class_for_each_device(const struct class *class, const struct device *start, void *data, 97 int (*fn)(struct device *dev, void *data)); 98 struct device *class_find_device(const struct class *class, const struct device *start, 99 const void *data, int (*match)(struct device *, const void *)); 100 101 /** 102 * class_find_device_by_name - device iterator for locating a particular device 103 * of a specific name. 104 * @class: class type 105 * @name: name of the device to match 106 */ 107 static inline struct device *class_find_device_by_name(const struct class *class, 108 const char *name) 109 { 110 return class_find_device(class, NULL, name, device_match_name); 111 } 112 113 /** 114 * class_find_device_by_of_node : device iterator for locating a particular device 115 * matching the of_node. 116 * @class: class type 117 * @np: of_node of the device to match. 118 */ 119 static inline struct device *class_find_device_by_of_node(const struct class *class, 120 const struct device_node *np) 121 { 122 return class_find_device(class, NULL, np, device_match_of_node); 123 } 124 125 /** 126 * class_find_device_by_fwnode : device iterator for locating a particular device 127 * matching the fwnode. 128 * @class: class type 129 * @fwnode: fwnode of the device to match. 130 */ 131 static inline struct device *class_find_device_by_fwnode(const struct class *class, 132 const struct fwnode_handle *fwnode) 133 { 134 return class_find_device(class, NULL, fwnode, device_match_fwnode); 135 } 136 137 /** 138 * class_find_device_by_devt : device iterator for locating a particular device 139 * matching the device type. 140 * @class: class type 141 * @devt: device type of the device to match. 142 */ 143 static inline struct device *class_find_device_by_devt(const struct class *class, 144 dev_t devt) 145 { 146 return class_find_device(class, NULL, &devt, device_match_devt); 147 } 148 149 #ifdef CONFIG_ACPI 150 struct acpi_device; 151 /** 152 * class_find_device_by_acpi_dev : device iterator for locating a particular 153 * device matching the ACPI_COMPANION device. 154 * @class: class type 155 * @adev: ACPI_COMPANION device to match. 156 */ 157 static inline struct device *class_find_device_by_acpi_dev(const struct class *class, 158 const struct acpi_device *adev) 159 { 160 return class_find_device(class, NULL, adev, device_match_acpi_dev); 161 } 162 #else 163 static inline struct device *class_find_device_by_acpi_dev(const struct class *class, 164 const void *adev) 165 { 166 return NULL; 167 } 168 #endif 169 170 struct class_attribute { 171 struct attribute attr; 172 ssize_t (*show)(const struct class *class, const struct class_attribute *attr, 173 char *buf); 174 ssize_t (*store)(const struct class *class, const struct class_attribute *attr, 175 const char *buf, size_t count); 176 }; 177 178 #define CLASS_ATTR_RW(_name) \ 179 struct class_attribute class_attr_##_name = __ATTR_RW(_name) 180 #define CLASS_ATTR_RO(_name) \ 181 struct class_attribute class_attr_##_name = __ATTR_RO(_name) 182 #define CLASS_ATTR_WO(_name) \ 183 struct class_attribute class_attr_##_name = __ATTR_WO(_name) 184 185 int __must_check class_create_file_ns(const struct class *class, const struct class_attribute *attr, 186 const void *ns); 187 void class_remove_file_ns(const struct class *class, const struct class_attribute *attr, 188 const void *ns); 189 190 static inline int __must_check class_create_file(const struct class *class, 191 const struct class_attribute *attr) 192 { 193 return class_create_file_ns(class, attr, NULL); 194 } 195 196 static inline void class_remove_file(const struct class *class, 197 const struct class_attribute *attr) 198 { 199 return class_remove_file_ns(class, attr, NULL); 200 } 201 202 /* Simple class attribute that is just a static string */ 203 struct class_attribute_string { 204 struct class_attribute attr; 205 char *str; 206 }; 207 208 /* Currently read-only only */ 209 #define _CLASS_ATTR_STRING(_name, _mode, _str) \ 210 { __ATTR(_name, _mode, show_class_attr_string, NULL), _str } 211 #define CLASS_ATTR_STRING(_name, _mode, _str) \ 212 struct class_attribute_string class_attr_##_name = \ 213 _CLASS_ATTR_STRING(_name, _mode, _str) 214 215 ssize_t show_class_attr_string(const struct class *class, const struct class_attribute *attr, 216 char *buf); 217 218 struct class_interface { 219 struct list_head node; 220 const struct class *class; 221 222 int (*add_dev) (struct device *dev); 223 void (*remove_dev) (struct device *dev); 224 }; 225 226 int __must_check class_interface_register(struct class_interface *); 227 void class_interface_unregister(struct class_interface *); 228 229 struct class * __must_check class_create(const char *name); 230 void class_destroy(const struct class *cls); 231 232 #endif /* _DEVICE_CLASS_H_ */ 233