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>
21 #include <linux/mutex.h>
24 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
26 static ssize_t
class_attr_show(struct kobject
*kobj
, struct attribute
*attr
,
29 struct class_attribute
*class_attr
= to_class_attr(attr
);
30 struct class_private
*cp
= to_class(kobj
);
34 ret
= class_attr
->show(cp
->class, buf
);
38 static ssize_t
class_attr_store(struct kobject
*kobj
, struct attribute
*attr
,
39 const char *buf
, size_t count
)
41 struct class_attribute
*class_attr
= to_class_attr(attr
);
42 struct class_private
*cp
= to_class(kobj
);
45 if (class_attr
->store
)
46 ret
= class_attr
->store(cp
->class, buf
, count
);
50 static void class_release(struct kobject
*kobj
)
52 struct class_private
*cp
= to_class(kobj
);
53 struct class *class = cp
->class;
55 pr_debug("class '%s': release.\n", class->name
);
57 if (class->class_release
)
58 class->class_release(class);
60 pr_debug("class '%s' does not have a release() function, "
61 "be careful\n", class->name
);
64 static struct sysfs_ops class_sysfs_ops
= {
65 .show
= class_attr_show
,
66 .store
= class_attr_store
,
69 static struct kobj_type class_ktype
= {
70 .sysfs_ops
= &class_sysfs_ops
,
71 .release
= class_release
,
74 /* Hotplug events for classes go to the class class_subsys */
75 static struct kset
*class_kset
;
78 int class_create_file(struct class *cls
, const struct class_attribute
*attr
)
82 error
= sysfs_create_file(&cls
->p
->class_subsys
.kobj
,
89 void class_remove_file(struct class *cls
, const struct class_attribute
*attr
)
92 sysfs_remove_file(&cls
->p
->class_subsys
.kobj
, &attr
->attr
);
95 static struct class *class_get(struct class *cls
)
98 kset_get(&cls
->p
->class_subsys
);
102 static void class_put(struct class *cls
)
105 kset_put(&cls
->p
->class_subsys
);
108 static int add_class_attrs(struct class *cls
)
113 if (cls
->class_attrs
) {
114 for (i
= 0; attr_name(cls
->class_attrs
[i
]); i
++) {
115 error
= class_create_file(cls
, &cls
->class_attrs
[i
]);
124 class_remove_file(cls
, &cls
->class_attrs
[i
]);
128 static void remove_class_attrs(struct class *cls
)
132 if (cls
->class_attrs
) {
133 for (i
= 0; attr_name(cls
->class_attrs
[i
]); i
++)
134 class_remove_file(cls
, &cls
->class_attrs
[i
]);
138 int __class_register(struct class *cls
, struct lock_class_key
*key
)
140 struct class_private
*cp
;
143 pr_debug("device class '%s': registering\n", cls
->name
);
145 cp
= kzalloc(sizeof(*cp
), GFP_KERNEL
);
148 INIT_LIST_HEAD(&cp
->class_devices
);
149 INIT_LIST_HEAD(&cp
->class_interfaces
);
150 kset_init(&cp
->class_dirs
);
151 __mutex_init(&cp
->class_mutex
, "struct class mutex", key
);
152 error
= kobject_set_name(&cp
->class_subsys
.kobj
, "%s", cls
->name
);
158 /* set the default /sys/dev directory for devices of this class */
160 cls
->dev_kobj
= sysfs_dev_char_kobj
;
162 #if defined(CONFIG_SYSFS_DEPRECATED) && defined(CONFIG_BLOCK)
163 /* let the block class directory show up in the root of sysfs */
164 if (cls
!= &block_class
)
165 cp
->class_subsys
.kobj
.kset
= class_kset
;
167 cp
->class_subsys
.kobj
.kset
= class_kset
;
169 cp
->class_subsys
.kobj
.ktype
= &class_ktype
;
173 error
= kset_register(&cp
->class_subsys
);
178 error
= add_class_attrs(class_get(cls
));
182 EXPORT_SYMBOL_GPL(__class_register
);
184 void class_unregister(struct class *cls
)
186 pr_debug("device class '%s': unregistering\n", cls
->name
);
187 remove_class_attrs(cls
);
188 kset_unregister(&cls
->p
->class_subsys
);
191 static void class_create_release(struct class *cls
)
193 pr_debug("%s called for %s\n", __func__
, cls
->name
);
198 * class_create - create a struct class structure
199 * @owner: pointer to the module that is to "own" this struct class
200 * @name: pointer to a string for the name of this class.
202 * This is used to create a struct class pointer that can then be used
203 * in calls to device_create().
205 * Note, the pointer created here is to be destroyed when finished by
206 * making a call to class_destroy().
208 struct class *__class_create(struct module
*owner
, const char *name
,
209 struct lock_class_key
*key
)
214 cls
= kzalloc(sizeof(*cls
), GFP_KERNEL
);
222 cls
->class_release
= class_create_release
;
224 retval
= __class_register(cls
, key
);
232 return ERR_PTR(retval
);
234 EXPORT_SYMBOL_GPL(__class_create
);
237 * class_destroy - destroys a struct class structure
238 * @cls: pointer to the struct class that is to be destroyed
240 * Note, the pointer to be destroyed must have been created with a call
243 void class_destroy(struct class *cls
)
245 if ((cls
== NULL
) || (IS_ERR(cls
)))
248 class_unregister(cls
);
251 #ifdef CONFIG_SYSFS_DEPRECATED
252 char *make_class_name(const char *name
, struct kobject
*kobj
)
257 size
= strlen(name
) + strlen(kobject_name(kobj
)) + 2;
259 class_name
= kmalloc(size
, GFP_KERNEL
);
263 strcpy(class_name
, name
);
264 strcat(class_name
, ":");
265 strcat(class_name
, kobject_name(kobj
));
271 * class_for_each_device - device iterator
272 * @class: the class we're iterating
273 * @start: the device to start with in the list, if any.
274 * @data: data for the callback
275 * @fn: function to be called for each device
277 * Iterate over @class's list of devices, and call @fn for each,
278 * passing it @data. If @start is set, the list iteration will start
279 * there, otherwise if it is NULL, the iteration starts at the
280 * beginning of the list.
282 * We check the return of @fn each time. If it returns anything
283 * other than 0, we break out and return that value.
285 * Note, we hold class->class_mutex in this function, so it can not be
286 * re-acquired in @fn, otherwise it will self-deadlocking. For
287 * example, calls to add or remove class members would be verboten.
289 int class_for_each_device(struct class *class, struct device
*start
,
290 void *data
, int (*fn
)(struct device
*, void *))
297 mutex_lock(&class->p
->class_mutex
);
298 list_for_each_entry(dev
, &class->p
->class_devices
, node
) {
304 dev
= get_device(dev
);
305 error
= fn(dev
, data
);
310 mutex_unlock(&class->p
->class_mutex
);
314 EXPORT_SYMBOL_GPL(class_for_each_device
);
317 * class_find_device - device iterator for locating a particular device
318 * @class: the class we're iterating
319 * @start: Device to begin with
320 * @data: data for the match function
321 * @match: function to check device
323 * This is similar to the class_for_each_dev() function above, but it
324 * returns a reference to a device that is 'found' for later use, as
325 * determined by the @match callback.
327 * The callback should return 0 if the device doesn't match and non-zero
328 * if it does. If the callback returns non-zero, this function will
329 * return to the caller and not iterate over any more devices.
331 * Note, you will need to drop the reference with put_device() after use.
333 * We hold class->class_mutex in this function, so it can not be
334 * re-acquired in @match, otherwise it will self-deadlocking. For
335 * example, calls to add or remove class members would be verboten.
337 struct device
*class_find_device(struct class *class, struct device
*start
,
339 int (*match
)(struct device
*, void *))
347 mutex_lock(&class->p
->class_mutex
);
348 list_for_each_entry(dev
, &class->p
->class_devices
, node
) {
354 dev
= get_device(dev
);
355 if (match(dev
, data
)) {
361 mutex_unlock(&class->p
->class_mutex
);
363 return found
? dev
: NULL
;
365 EXPORT_SYMBOL_GPL(class_find_device
);
367 int class_interface_register(struct class_interface
*class_intf
)
369 struct class *parent
;
372 if (!class_intf
|| !class_intf
->class)
375 parent
= class_get(class_intf
->class);
379 mutex_lock(&parent
->p
->class_mutex
);
380 list_add_tail(&class_intf
->node
, &parent
->p
->class_interfaces
);
381 if (class_intf
->add_dev
) {
382 list_for_each_entry(dev
, &parent
->p
->class_devices
, node
)
383 class_intf
->add_dev(dev
, class_intf
);
385 mutex_unlock(&parent
->p
->class_mutex
);
390 void class_interface_unregister(struct class_interface
*class_intf
)
392 struct class *parent
= class_intf
->class;
398 mutex_lock(&parent
->p
->class_mutex
);
399 list_del_init(&class_intf
->node
);
400 if (class_intf
->remove_dev
) {
401 list_for_each_entry(dev
, &parent
->p
->class_devices
, node
)
402 class_intf
->remove_dev(dev
, class_intf
);
404 mutex_unlock(&parent
->p
->class_mutex
);
409 int __init
classes_init(void)
411 class_kset
= kset_create_and_add("class", NULL
, NULL
);
417 EXPORT_SYMBOL_GPL(class_create_file
);
418 EXPORT_SYMBOL_GPL(class_remove_file
);
419 EXPORT_SYMBOL_GPL(class_unregister
);
420 EXPORT_SYMBOL_GPL(class_destroy
);
422 EXPORT_SYMBOL_GPL(class_interface_register
);
423 EXPORT_SYMBOL_GPL(class_interface_unregister
);