[PATCH] class: add kerneldoc for the new class functions.
[pandora-kernel.git] / drivers / base / class.c
1 /*
2  * class.c - basic device class management
3  *
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.
8  *
9  * This file is released under the GPLv2
10  *
11  */
12
13 #include <linux/config.h>
14 #include <linux/device.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/string.h>
18 #include <linux/kdev_t.h>
19 #include <linux/err.h>
20 #include "base.h"
21
22 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
23 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
24
25 static ssize_t
26 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
27 {
28         struct class_attribute * class_attr = to_class_attr(attr);
29         struct class * dc = to_class(kobj);
30         ssize_t ret = -EIO;
31
32         if (class_attr->show)
33                 ret = class_attr->show(dc, buf);
34         return ret;
35 }
36
37 static ssize_t
38 class_attr_store(struct kobject * kobj, struct attribute * attr,
39                  const char * buf, size_t count)
40 {
41         struct class_attribute * class_attr = to_class_attr(attr);
42         struct class * dc = to_class(kobj);
43         ssize_t ret = -EIO;
44
45         if (class_attr->store)
46                 ret = class_attr->store(dc, buf, count);
47         return ret;
48 }
49
50 static void class_release(struct kobject * kobj)
51 {
52         struct class *class = to_class(kobj);
53
54         pr_debug("class '%s': release.\n", class->name);
55
56         if (class->class_release)
57                 class->class_release(class);
58         else
59                 pr_debug("class '%s' does not have a release() function, "
60                          "be careful\n", class->name);
61 }
62
63 static struct sysfs_ops class_sysfs_ops = {
64         .show   = class_attr_show,
65         .store  = class_attr_store,
66 };
67
68 static struct kobj_type ktype_class = {
69         .sysfs_ops      = &class_sysfs_ops,
70         .release        = class_release,
71 };
72
73 /* Hotplug events for classes go to the class_obj subsys */
74 static decl_subsys(class, &ktype_class, NULL);
75
76
77 int class_create_file(struct class * cls, const struct class_attribute * attr)
78 {
79         int error;
80         if (cls) {
81                 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
82         } else
83                 error = -EINVAL;
84         return error;
85 }
86
87 void class_remove_file(struct class * cls, const struct class_attribute * attr)
88 {
89         if (cls)
90                 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
91 }
92
93 struct class * class_get(struct class * cls)
94 {
95         if (cls)
96                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
97         return NULL;
98 }
99
100 void class_put(struct class * cls)
101 {
102         subsys_put(&cls->subsys);
103 }
104
105
106 static int add_class_attrs(struct class * cls)
107 {
108         int i;
109         int error = 0;
110
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]);
114                         if (error)
115                                 goto Err;
116                 }
117         }
118  Done:
119         return error;
120  Err:
121         while (--i >= 0)
122                 class_remove_file(cls,&cls->class_attrs[i]);
123         goto Done;
124 }
125
126 static void remove_class_attrs(struct class * cls)
127 {
128         int i;
129
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]);
133         }
134 }
135
136 int class_register(struct class * cls)
137 {
138         int error;
139
140         pr_debug("device class '%s': registering\n", cls->name);
141
142         INIT_LIST_HEAD(&cls->children);
143         INIT_LIST_HEAD(&cls->interfaces);
144         init_MUTEX(&cls->sem);
145         error = kobject_set_name(&cls->subsys.kset.kobj, "%s", cls->name);
146         if (error)
147                 return error;
148
149         subsys_set_kset(cls, class_subsys);
150
151         error = subsystem_register(&cls->subsys);
152         if (!error) {
153                 error = add_class_attrs(class_get(cls));
154                 class_put(cls);
155         }
156         return error;
157 }
158
159 void class_unregister(struct class * cls)
160 {
161         pr_debug("device class '%s': unregistering\n", cls->name);
162         remove_class_attrs(cls);
163         subsystem_unregister(&cls->subsys);
164 }
165
166 static void class_create_release(struct class *cls)
167 {
168         kfree(cls);
169 }
170
171 static void class_device_create_release(struct class_device *class_dev)
172 {
173         kfree(class_dev);
174 }
175
176 /**
177  * class_create - create a struct class structure
178  * @owner: pointer to the module that is to "own" this struct class
179  * @name: pointer to a string for the name of this class.
180  *
181  * This is used to create a struct class pointer that can then be used
182  * in calls to class_device_create().
183  *
184  * Note, the pointer created here is to be destroyed when finished by
185  * making a call to class_destroy().
186  */
187 struct class *class_create(struct module *owner, char *name)
188 {
189         struct class *cls;
190         int retval;
191
192         cls = kmalloc(sizeof(struct class), GFP_KERNEL);
193         if (!cls) {
194                 retval = -ENOMEM;
195                 goto error;
196         }
197         memset(cls, 0x00, sizeof(struct class));
198
199         cls->name = name;
200         cls->owner = owner;
201         cls->class_release = class_create_release;
202         cls->release = class_device_create_release;
203
204         retval = class_register(cls);
205         if (retval)
206                 goto error;
207
208         return cls;
209
210 error:
211         kfree(cls);
212         return ERR_PTR(retval);
213 }
214
215 /**
216  * class_destroy - destroys a struct class structure
217  * @cs: pointer to the struct class that is to be destroyed
218  *
219  * Note, the pointer to be destroyed must have been created with a call
220  * to class_create().
221  */
222 void class_destroy(struct class *cls)
223 {
224         if ((cls == NULL) || (IS_ERR(cls)))
225                 return;
226
227         class_unregister(cls);
228 }
229
230 /* Class Device Stuff */
231
232 int class_device_create_file(struct class_device * class_dev,
233                              const struct class_device_attribute * attr)
234 {
235         int error = -EINVAL;
236         if (class_dev)
237                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
238         return error;
239 }
240
241 void class_device_remove_file(struct class_device * class_dev,
242                               const struct class_device_attribute * attr)
243 {
244         if (class_dev)
245                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
246 }
247
248 int class_device_create_bin_file(struct class_device *class_dev,
249                                  struct bin_attribute *attr)
250 {
251         int error = -EINVAL;
252         if (class_dev)
253                 error = sysfs_create_bin_file(&class_dev->kobj, attr);
254         return error;
255 }
256
257 void class_device_remove_bin_file(struct class_device *class_dev,
258                                   struct bin_attribute *attr)
259 {
260         if (class_dev)
261                 sysfs_remove_bin_file(&class_dev->kobj, attr);
262 }
263
264 static ssize_t
265 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
266                        char * buf)
267 {
268         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
269         struct class_device * cd = to_class_dev(kobj);
270         ssize_t ret = 0;
271
272         if (class_dev_attr->show)
273                 ret = class_dev_attr->show(cd, buf);
274         return ret;
275 }
276
277 static ssize_t
278 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
279                         const char * buf, size_t count)
280 {
281         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
282         struct class_device * cd = to_class_dev(kobj);
283         ssize_t ret = 0;
284
285         if (class_dev_attr->store)
286                 ret = class_dev_attr->store(cd, buf, count);
287         return ret;
288 }
289
290 static struct sysfs_ops class_dev_sysfs_ops = {
291         .show   = class_device_attr_show,
292         .store  = class_device_attr_store,
293 };
294
295 static void class_dev_release(struct kobject * kobj)
296 {
297         struct class_device *cd = to_class_dev(kobj);
298         struct class * cls = cd->class;
299
300         pr_debug("device class '%s': release.\n", cd->class_id);
301
302         if (cls->release)
303                 cls->release(cd);
304         else {
305                 printk(KERN_ERR "Device class '%s' does not have a release() function, "
306                         "it is broken and must be fixed.\n",
307                         cd->class_id);
308                 WARN_ON(1);
309         }
310 }
311
312 static struct kobj_type ktype_class_device = {
313         .sysfs_ops      = &class_dev_sysfs_ops,
314         .release        = class_dev_release,
315 };
316
317 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
318 {
319         struct kobj_type *ktype = get_ktype(kobj);
320
321         if (ktype == &ktype_class_device) {
322                 struct class_device *class_dev = to_class_dev(kobj);
323                 if (class_dev->class)
324                         return 1;
325         }
326         return 0;
327 }
328
329 static const char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
330 {
331         struct class_device *class_dev = to_class_dev(kobj);
332
333         return class_dev->class->name;
334 }
335
336 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
337                          int num_envp, char *buffer, int buffer_size)
338 {
339         struct class_device *class_dev = to_class_dev(kobj);
340         int i = 0;
341         int length = 0;
342         int retval = 0;
343
344         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
345
346         if (class_dev->dev) {
347                 /* add physical device, backing this device  */
348                 struct device *dev = class_dev->dev;
349                 char *path = kobject_get_path(&dev->kobj, GFP_KERNEL);
350
351                 add_hotplug_env_var(envp, num_envp, &i, buffer, buffer_size,
352                                     &length, "PHYSDEVPATH=%s", path);
353                 kfree(path);
354
355                 if (dev->bus)
356                         add_hotplug_env_var(envp, num_envp, &i,
357                                             buffer, buffer_size, &length,
358                                             "PHYSDEVBUS=%s", dev->bus->name);
359
360                 if (dev->driver)
361                         add_hotplug_env_var(envp, num_envp, &i,
362                                             buffer, buffer_size, &length,
363                                             "PHYSDEVDRIVER=%s", dev->driver->name);
364         }
365
366         if (MAJOR(class_dev->devt)) {
367                 add_hotplug_env_var(envp, num_envp, &i,
368                                     buffer, buffer_size, &length,
369                                     "MAJOR=%u", MAJOR(class_dev->devt));
370
371                 add_hotplug_env_var(envp, num_envp, &i,
372                                     buffer, buffer_size, &length,
373                                     "MINOR=%u", MINOR(class_dev->devt));
374         }
375
376         /* terminate, set to next free slot, shrink available space */
377         envp[i] = NULL;
378         envp = &envp[i];
379         num_envp -= i;
380         buffer = &buffer[length];
381         buffer_size -= length;
382
383         if (class_dev->class->hotplug) {
384                 /* have the bus specific function add its stuff */
385                 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
386                                                     buffer, buffer_size);
387                         if (retval) {
388                         pr_debug ("%s - hotplug() returned %d\n",
389                                   __FUNCTION__, retval);
390                 }
391         }
392
393         return retval;
394 }
395
396 static struct kset_hotplug_ops class_hotplug_ops = {
397         .filter =       class_hotplug_filter,
398         .name =         class_hotplug_name,
399         .hotplug =      class_hotplug,
400 };
401
402 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
403
404
405 static int class_device_add_attrs(struct class_device * cd)
406 {
407         int i;
408         int error = 0;
409         struct class * cls = cd->class;
410
411         if (cls->class_dev_attrs) {
412                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
413                         error = class_device_create_file(cd,
414                                                          &cls->class_dev_attrs[i]);
415                         if (error)
416                                 goto Err;
417                 }
418         }
419  Done:
420         return error;
421  Err:
422         while (--i >= 0)
423                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
424         goto Done;
425 }
426
427 static void class_device_remove_attrs(struct class_device * cd)
428 {
429         int i;
430         struct class * cls = cd->class;
431
432         if (cls->class_dev_attrs) {
433                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
434                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
435         }
436 }
437
438 static ssize_t show_dev(struct class_device *class_dev, char *buf)
439 {
440         return print_dev_t(buf, class_dev->devt);
441 }
442
443 void class_device_initialize(struct class_device *class_dev)
444 {
445         kobj_set_kset_s(class_dev, class_obj_subsys);
446         kobject_init(&class_dev->kobj);
447         INIT_LIST_HEAD(&class_dev->node);
448 }
449
450 int class_device_add(struct class_device *class_dev)
451 {
452         struct class * parent = NULL;
453         struct class_interface * class_intf;
454         int error;
455
456         class_dev = class_device_get(class_dev);
457         if (!class_dev)
458                 return -EINVAL;
459
460         if (!strlen(class_dev->class_id)) {
461                 error = -EINVAL;
462                 goto register_done;
463         }
464
465         parent = class_get(class_dev->class);
466
467         pr_debug("CLASS: registering class device: ID = '%s'\n",
468                  class_dev->class_id);
469
470         /* first, register with generic layer. */
471         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
472         if (parent)
473                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
474
475         if ((error = kobject_add(&class_dev->kobj)))
476                 goto register_done;
477
478         /* add the needed attributes to this device */
479         if (MAJOR(class_dev->devt)) {
480                 struct class_device_attribute *attr;
481                 attr = kmalloc(sizeof(*attr), GFP_KERNEL);
482                 if (!attr) {
483                         error = -ENOMEM;
484                         kobject_del(&class_dev->kobj);
485                         goto register_done;
486                 }
487                 memset(attr, sizeof(*attr), 0x00);
488                 attr->attr.name = "dev";
489                 attr->attr.mode = S_IRUGO;
490                 attr->attr.owner = parent->owner;
491                 attr->show = show_dev;
492                 attr->store = NULL;
493                 class_device_create_file(class_dev, attr);
494                 class_dev->devt_attr = attr;
495         }
496
497         class_device_add_attrs(class_dev);
498         if (class_dev->dev)
499                 sysfs_create_link(&class_dev->kobj,
500                                   &class_dev->dev->kobj, "device");
501
502         /* notify any interfaces this device is now here */
503         if (parent) {
504                 down(&parent->sem);
505                 list_add_tail(&class_dev->node, &parent->children);
506                 list_for_each_entry(class_intf, &parent->interfaces, node)
507                         if (class_intf->add)
508                                 class_intf->add(class_dev);
509                 up(&parent->sem);
510         }
511         kobject_hotplug(&class_dev->kobj, KOBJ_ADD);
512
513  register_done:
514         if (error && parent)
515                 class_put(parent);
516         class_device_put(class_dev);
517         return error;
518 }
519
520 int class_device_register(struct class_device *class_dev)
521 {
522         class_device_initialize(class_dev);
523         return class_device_add(class_dev);
524 }
525
526 /**
527  * class_device_create - creates a class device and registers it with sysfs
528  * @cs: pointer to the struct class that this device should be registered to.
529  * @dev: the dev_t for the char device to be added.
530  * @device: a pointer to a struct device that is assiociated with this class device.
531  * @fmt: string for the class device's name
532  *
533  * This function can be used by char device classes.  A struct
534  * class_device will be created in sysfs, registered to the specified
535  * class.  A "dev" file will be created, showing the dev_t for the
536  * device.  The pointer to the struct class_device will be returned from
537  * the call.  Any further sysfs files that might be required can be
538  * created using this pointer.
539  *
540  * Note: the struct class passed to this function must have previously
541  * been created with a call to class_create().
542  */
543 struct class_device *class_device_create(struct class *cls, dev_t devt,
544                                          struct device *device, char *fmt, ...)
545 {
546         va_list args;
547         struct class_device *class_dev = NULL;
548         int retval = -ENODEV;
549
550         if (cls == NULL || IS_ERR(cls))
551                 goto error;
552
553         class_dev = kmalloc(sizeof(struct class_device), GFP_KERNEL);
554         if (!class_dev) {
555                 retval = -ENOMEM;
556                 goto error;
557         }
558         memset(class_dev, 0x00, sizeof(struct class_device));
559
560         class_dev->devt = devt;
561         class_dev->dev = device;
562         class_dev->class = cls;
563
564         va_start(args, fmt);
565         vsnprintf(class_dev->class_id, BUS_ID_SIZE, fmt, args);
566         va_end(args);
567         retval = class_device_register(class_dev);
568         if (retval)
569                 goto error;
570
571         return class_dev;
572
573 error:
574         kfree(class_dev);
575         return ERR_PTR(retval);
576 }
577
578 void class_device_del(struct class_device *class_dev)
579 {
580         struct class * parent = class_dev->class;
581         struct class_interface * class_intf;
582
583         if (parent) {
584                 down(&parent->sem);
585                 list_del_init(&class_dev->node);
586                 list_for_each_entry(class_intf, &parent->interfaces, node)
587                         if (class_intf->remove)
588                                 class_intf->remove(class_dev);
589                 up(&parent->sem);
590         }
591
592         if (class_dev->dev)
593                 sysfs_remove_link(&class_dev->kobj, "device");
594         if (class_dev->devt_attr) {
595                 class_device_remove_file(class_dev, class_dev->devt_attr);
596                 kfree(class_dev->devt_attr);
597                 class_dev->devt_attr = NULL;
598         }
599         class_device_remove_attrs(class_dev);
600
601         kobject_hotplug(&class_dev->kobj, KOBJ_REMOVE);
602         kobject_del(&class_dev->kobj);
603
604         if (parent)
605                 class_put(parent);
606 }
607
608 void class_device_unregister(struct class_device *class_dev)
609 {
610         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
611                  class_dev->class_id);
612         class_device_del(class_dev);
613         class_device_put(class_dev);
614 }
615
616 /**
617  * class_device_destroy - removes a class device that was created with class_device_create()
618  * @cls: the pointer to the struct class that this device was registered * with.
619  * @dev: the dev_t of the device that was previously registered.
620  *
621  * This call unregisters and cleans up a class device that was created with a
622  * call to class_device_create()
623  */
624 void class_device_destroy(struct class *cls, dev_t devt)
625 {
626         struct class_device *class_dev = NULL;
627         struct class_device *class_dev_tmp;
628
629         down(&cls->sem);
630         list_for_each_entry(class_dev_tmp, &cls->children, node) {
631                 if (class_dev_tmp->devt == devt) {
632                         class_dev = class_dev_tmp;
633                         break;
634                 }
635         }
636         up(&cls->sem);
637
638         if (class_dev)
639                 class_device_unregister(class_dev);
640 }
641
642 int class_device_rename(struct class_device *class_dev, char *new_name)
643 {
644         int error = 0;
645
646         class_dev = class_device_get(class_dev);
647         if (!class_dev)
648                 return -EINVAL;
649
650         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
651                  new_name);
652
653         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
654
655         error = kobject_rename(&class_dev->kobj, new_name);
656
657         class_device_put(class_dev);
658
659         return error;
660 }
661
662 struct class_device * class_device_get(struct class_device *class_dev)
663 {
664         if (class_dev)
665                 return to_class_dev(kobject_get(&class_dev->kobj));
666         return NULL;
667 }
668
669 void class_device_put(struct class_device *class_dev)
670 {
671         kobject_put(&class_dev->kobj);
672 }
673
674
675 int class_interface_register(struct class_interface *class_intf)
676 {
677         struct class *parent;
678         struct class_device *class_dev;
679
680         if (!class_intf || !class_intf->class)
681                 return -ENODEV;
682
683         parent = class_get(class_intf->class);
684         if (!parent)
685                 return -EINVAL;
686
687         down(&parent->sem);
688         list_add_tail(&class_intf->node, &parent->interfaces);
689         if (class_intf->add) {
690                 list_for_each_entry(class_dev, &parent->children, node)
691                         class_intf->add(class_dev);
692         }
693         up(&parent->sem);
694
695         return 0;
696 }
697
698 void class_interface_unregister(struct class_interface *class_intf)
699 {
700         struct class * parent = class_intf->class;
701         struct class_device *class_dev;
702
703         if (!parent)
704                 return;
705
706         down(&parent->sem);
707         list_del_init(&class_intf->node);
708         if (class_intf->remove) {
709                 list_for_each_entry(class_dev, &parent->children, node)
710                         class_intf->remove(class_dev);
711         }
712         up(&parent->sem);
713
714         class_put(parent);
715 }
716
717
718
719 int __init classes_init(void)
720 {
721         int retval;
722
723         retval = subsystem_register(&class_subsys);
724         if (retval)
725                 return retval;
726
727         /* ick, this is ugly, the things we go through to keep from showing up
728          * in sysfs... */
729         subsystem_init(&class_obj_subsys);
730         if (!class_obj_subsys.kset.subsys)
731                         class_obj_subsys.kset.subsys = &class_obj_subsys;
732         return 0;
733 }
734
735 EXPORT_SYMBOL_GPL(class_create_file);
736 EXPORT_SYMBOL_GPL(class_remove_file);
737 EXPORT_SYMBOL_GPL(class_register);
738 EXPORT_SYMBOL_GPL(class_unregister);
739 EXPORT_SYMBOL_GPL(class_get);
740 EXPORT_SYMBOL_GPL(class_put);
741 EXPORT_SYMBOL_GPL(class_create);
742 EXPORT_SYMBOL_GPL(class_destroy);
743
744 EXPORT_SYMBOL_GPL(class_device_register);
745 EXPORT_SYMBOL_GPL(class_device_unregister);
746 EXPORT_SYMBOL_GPL(class_device_initialize);
747 EXPORT_SYMBOL_GPL(class_device_add);
748 EXPORT_SYMBOL_GPL(class_device_del);
749 EXPORT_SYMBOL_GPL(class_device_get);
750 EXPORT_SYMBOL_GPL(class_device_put);
751 EXPORT_SYMBOL_GPL(class_device_create);
752 EXPORT_SYMBOL_GPL(class_device_destroy);
753 EXPORT_SYMBOL_GPL(class_device_create_file);
754 EXPORT_SYMBOL_GPL(class_device_remove_file);
755 EXPORT_SYMBOL_GPL(class_device_create_bin_file);
756 EXPORT_SYMBOL_GPL(class_device_remove_bin_file);
757
758 EXPORT_SYMBOL_GPL(class_interface_register);
759 EXPORT_SYMBOL_GPL(class_interface_unregister);