2 * class.c - basic device class management
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2003-2004 Greg Kroah-Hartman
7 * Copyright (c) 2003-2004 IBM Corp.
9 * This file is released under the GPLv2
13 #include <linux/device.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/string.h>
17 #include <linux/kdev_t.h>
18 #include <linux/err.h>
19 #include <linux/slab.h>
20 #include <linux/genhd.h>
23 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
25 static ssize_t
class_attr_show(struct kobject
*kobj
, struct attribute
*attr
,
28 struct class_attribute
*class_attr
= to_class_attr(attr
);
29 struct class_private
*cp
= to_class(kobj
);
33 ret
= class_attr
->show(cp
->class, buf
);
37 static ssize_t
class_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
38 const char *buf
, size_t count
)
40 struct class_attribute
*class_attr
= to_class_attr(attr
);
41 struct class_private
*cp
= to_class(kobj
);
44 if (class_attr
->store
)
45 ret
= class_attr
->store(cp
->class, buf
, count
);
49 static void class_release(struct kobject
*kobj
)
51 struct class_private
*cp
= to_class(kobj
);
52 struct class *class = cp
->class;
54 pr_debug("class '%s': release.\n", class->name
);
56 if (class->class_release
)
57 class->class_release(class);
59 pr_debug("class '%s' does not have a release() function, "
60 "be careful\n", class->name
);
63 static struct sysfs_ops class_sysfs_ops
= {
64 .show
= class_attr_show
,
65 .store
= class_attr_store
,
68 static struct kobj_type class_ktype
= {
69 .sysfs_ops
= &class_sysfs_ops
,
70 .release
= class_release
,
73 /* Hotplug events for classes go to the class_obj subsys */
74 static struct kset
*class_kset
;
77 int class_create_file(struct class *cls
, const struct class_attribute
*attr
)
81 error
= sysfs_create_file(&cls
->p
->subsys
.kobj
, &attr
->attr
);
87 void class_remove_file(struct class *cls
, const struct class_attribute
*attr
)
90 sysfs_remove_file(&cls
->p
->subsys
.kobj
, &attr
->attr
);
93 static struct class *class_get(struct class *cls
)
96 kset_get(&cls
->p
->subsys
);
100 static void class_put(struct class *cls
)
103 kset_put(&cls
->p
->subsys
);
106 static int add_class_attrs(struct class *cls
)
111 if (cls
->class_attrs
) {
112 for (i
= 0; attr_name(cls
->class_attrs
[i
]); i
++) {
113 error
= class_create_file(cls
, &cls
->class_attrs
[i
]);
122 class_remove_file(cls
, &cls
->class_attrs
[i
]);
126 static void remove_class_attrs(struct class *cls
)
130 if (cls
->class_attrs
) {
131 for (i
= 0; attr_name(cls
->class_attrs
[i
]); i
++)
132 class_remove_file(cls
, &cls
->class_attrs
[i
]);
136 int class_register(struct class *cls
)
138 struct class_private
*cp
;
141 pr_debug("device class '%s': registering\n", cls
->name
);
143 cp
= kzalloc(sizeof(*cp
), GFP_KERNEL
);
146 INIT_LIST_HEAD(&cp
->class_devices
);
147 INIT_LIST_HEAD(&cp
->interfaces
);
148 kset_init(&cp
->class_dirs
);
149 init_MUTEX(&cp
->sem
);
150 error
= kobject_set_name(&cp
->subsys
.kobj
, "%s", cls
->name
);
156 /* set the default /sys/dev directory for devices of this class */
158 cls
->dev_kobj
= sysfs_dev_char_kobj
;
160 #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)
161 /* let the block class directory show up in the root of sysfs */
162 if (cls
!= &block_class
)
163 cp
->subsys
.kobj
.kset
= class_kset
;
165 cp
->subsys
.kobj
.kset
= class_kset
;
167 cp
->subsys
.kobj
.ktype
= &class_ktype
;
171 error
= kset_register(&cp
->subsys
);
176 error
= add_class_attrs(class_get(cls
));
181 void class_unregister(struct class *cls
)
183 pr_debug("device class '%s': unregistering\n", cls
->name
);
184 remove_class_attrs(cls
);
185 kset_unregister(&cls
->p
->subsys
);
188 static void class_create_release(struct class *cls
)
190 pr_debug("%s called for %s\n", __func__
, cls
->name
);
195 * class_create - create a struct class structure
196 * @owner: pointer to the module that is to "own" this struct class
197 * @name: pointer to a string for the name of this class.
199 * This is used to create a struct class pointer that can then be used
200 * in calls to device_create().
202 * Note, the pointer created here is to be destroyed when finished by
203 * making a call to class_destroy().
205 struct class *class_create(struct module
*owner
, const char *name
)
210 cls
= kzalloc(sizeof(*cls
), GFP_KERNEL
);
218 cls
->class_release
= class_create_release
;
220 retval
= class_register(cls
);
228 return ERR_PTR(retval
);
232 * class_destroy - destroys a struct class structure
233 * @cls: pointer to the struct class that is to be destroyed
235 * Note, the pointer to be destroyed must have been created with a call
238 void class_destroy(struct class *cls
)
240 if ((cls
== NULL
) || (IS_ERR(cls
)))
243 class_unregister(cls
);
246 #ifdef CONFIG_SYSFS_DEPRECATED
247 char *make_class_name(const char *name
, struct kobject
*kobj
)
252 size
= strlen(name
) + strlen(kobject_name(kobj
)) + 2;
254 class_name
= kmalloc(size
, GFP_KERNEL
);
258 strcpy(class_name
, name
);
259 strcat(class_name
, ":");
260 strcat(class_name
, kobject_name(kobj
));
266 * class_for_each_device - device iterator
267 * @class: the class we're iterating
268 * @start: the device to start with in the list, if any.
269 * @data: data for the callback
270 * @fn: function to be called for each device
272 * Iterate over @class's list of devices, and call @fn for each,
273 * passing it @data. If @start is set, the list iteration will start
274 * there, otherwise if it is NULL, the iteration starts at the
275 * beginning of the list.
277 * We check the return of @fn each time. If it returns anything
278 * other than 0, we break out and return that value.
280 * Note, we hold class->sem in this function, so it can not be
281 * re-acquired in @fn, otherwise it will self-deadlocking. For
282 * example, calls to add or remove class members would be verboten.
284 int class_for_each_device(struct class *class, struct device
*start
,
285 void *data
, int (*fn
)(struct device
*, void *))
292 down(&class->p
->sem
);
293 list_for_each_entry(dev
, &class->p
->class_devices
, node
) {
299 dev
= get_device(dev
);
300 error
= fn(dev
, data
);
309 EXPORT_SYMBOL_GPL(class_for_each_device
);
312 * class_find_device - device iterator for locating a particular device
313 * @class: the class we're iterating
314 * @start: Device to begin with
315 * @data: data for the match function
316 * @match: function to check device
318 * This is similar to the class_for_each_dev() function above, but it
319 * returns a reference to a device that is 'found' for later use, as
320 * determined by the @match callback.
322 * The callback should return 0 if the device doesn't match and non-zero
323 * if it does. If the callback returns non-zero, this function will
324 * return to the caller and not iterate over any more devices.
326 * Note, you will need to drop the reference with put_device() after use.
328 * We hold class->sem in this function, so it can not be
329 * re-acquired in @match, otherwise it will self-deadlocking. For
330 * example, calls to add or remove class members would be verboten.
332 struct device
*class_find_device(struct class *class, struct device
*start
,
334 int (*match
)(struct device
*, void *))
342 down(&class->p
->sem
);
343 list_for_each_entry(dev
, &class->p
->class_devices
, node
) {
349 dev
= get_device(dev
);
350 if (match(dev
, data
)) {
358 return found
? dev
: NULL
;
360 EXPORT_SYMBOL_GPL(class_find_device
);
362 int class_interface_register(struct class_interface
*class_intf
)
364 struct class *parent
;
367 if (!class_intf
|| !class_intf
->class)
370 parent
= class_get(class_intf
->class);
374 down(&parent
->p
->sem
);
375 list_add_tail(&class_intf
->node
, &parent
->p
->interfaces
);
376 if (class_intf
->add_dev
) {
377 list_for_each_entry(dev
, &parent
->p
->class_devices
, node
)
378 class_intf
->add_dev(dev
, class_intf
);
385 void class_interface_unregister(struct class_interface
*class_intf
)
387 struct class *parent
= class_intf
->class;
393 down(&parent
->p
->sem
);
394 list_del_init(&class_intf
->node
);
395 if (class_intf
->remove_dev
) {
396 list_for_each_entry(dev
, &parent
->p
->class_devices
, node
)
397 class_intf
->remove_dev(dev
, class_intf
);
404 int __init
classes_init(void)
406 class_kset
= kset_create_and_add("class", NULL
, NULL
);
412 EXPORT_SYMBOL_GPL(class_create_file
);
413 EXPORT_SYMBOL_GPL(class_remove_file
);
414 EXPORT_SYMBOL_GPL(class_register
);
415 EXPORT_SYMBOL_GPL(class_unregister
);
416 EXPORT_SYMBOL_GPL(class_create
);
417 EXPORT_SYMBOL_GPL(class_destroy
);
419 EXPORT_SYMBOL_GPL(class_interface_register
);
420 EXPORT_SYMBOL_GPL(class_interface_unregister
);