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 Greg Kroah-Hartman
   7  * Copyright (c) 2003 IBM Corp.
   8  *
   9  * This file is released under the GPLv2
  10  *
  11  */
  12
  13 #undef DEBUG
  14
  15 #include <linux/device.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/string.h>
  19 #include "base.h"
  20
  21 #define to_class_attr(_attr) container_of(_attr,struct class_attribute,attr)
  22 #define to_class(obj) container_of(obj,struct class,subsys.kset.kobj)
  23
  24 static ssize_t
  25 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
  26 {
  27         struct class_attribute * class_attr = to_class_attr(attr);
  28         struct class * dc = to_class(kobj);
  29         ssize_t ret = 0;
  30
  31         if (class_attr->show)
  32                 ret = class_attr->show(dc,buf);
  33         return ret;
  34 }
  35
  36 static ssize_t
  37 class_attr_store(struct kobject * kobj, struct attribute * attr,
  38                  const char * buf, size_t count)
  39 {
  40         struct class_attribute * class_attr = to_class_attr(attr);
  41         struct class * dc = to_class(kobj);
  42         ssize_t ret = 0;
  43
  44         if (class_attr->store)
  45                 ret = class_attr->store(dc,buf,count);
  46         return ret;
  47 }
  48
  49 static struct sysfs_ops class_sysfs_ops = {
  50         .show   = class_attr_show,
  51         .store  = class_attr_store,
  52 };
  53
  54 static struct kobj_type ktype_class = {
  55         .sysfs_ops      = &class_sysfs_ops,
  56 };
  57
  58 /* Hotplug events for classes go to the class_obj subsys */
  59 static decl_subsys(class,&ktype_class,NULL);
  60
  61
  62 int class_create_file(struct class * cls, const struct class_attribute * attr)
  63 {
  64         int error;
  65         if (cls) {
  66                 error = sysfs_create_file(&cls->subsys.kset.kobj,&attr->attr);
  67         } else
  68                 error = -EINVAL;
  69         return error;
  70 }
  71
  72 void class_remove_file(struct class * cls, const struct class_attribute * attr)
  73 {
  74         if (cls)
  75                 sysfs_remove_file(&cls->subsys.kset.kobj,&attr->attr);
  76 }
  77
  78 struct class * class_get(struct class * cls)
  79 {
  80         if (cls)
  81                 return container_of(subsys_get(&cls->subsys),struct class,subsys);
  82         return NULL;
  83 }
  84
  85 void class_put(struct class * cls)
  86 {
  87         subsys_put(&cls->subsys);
  88 }
  89
  90 int class_register(struct class * cls)
  91 {
  92         pr_debug("device class '%s': registering\n",cls->name);
  93
  94         INIT_LIST_HEAD(&cls->children);
  95         INIT_LIST_HEAD(&cls->interfaces);
  96         kobject_set_name(&cls->subsys.kset.kobj,cls->name);
  97         subsys_set_kset(cls,class_subsys);
  98         subsystem_register(&cls->subsys);
  99
 100         return 0;
 101 }
 102
 103 void class_unregister(struct class * cls)
 104 {
 105         pr_debug("device class '%s': unregistering\n",cls->name);
 106         subsystem_unregister(&cls->subsys);
 107 }
 108
 109 /* Class Device Stuff */
 110
 111 int class_device_create_file(struct class_device * class_dev,
 112                              const struct class_device_attribute * attr)
 113 {
 114         int error = -EINVAL;
 115         if (class_dev)
 116                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 117         return error;
 118 }
 119
 120 void class_device_remove_file(struct class_device * class_dev,
 121                               const struct class_device_attribute * attr)
 122 {
 123         if (class_dev)
 124                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 125 }
 126
 127 static int class_device_dev_link(struct class_device * class_dev)
 128 {
 129         if (class_dev->dev)
 130                 return sysfs_create_link(&class_dev->kobj,
 131                                          &class_dev->dev->kobj, "device");
 132         return 0;
 133 }
 134
 135 static void class_device_dev_unlink(struct class_device * class_dev)
 136 {
 137         if (class_dev->dev)
 138                 sysfs_remove_link(&class_dev->kobj, "device");
 139 }
 140
 141 static int class_device_driver_link(struct class_device * class_dev)
 142 {
 143         if ((class_dev->dev) && (class_dev->dev->driver))
 144                 return sysfs_create_link(&class_dev->kobj,
 145                                          &class_dev->dev->driver->kobj, "driver");
 146         return 0;
 147 }
 148
 149 static void class_device_driver_unlink(struct class_device * class_dev)
 150 {
 151         if ((class_dev->dev) && (class_dev->dev->driver))
 152                 sysfs_remove_link(&class_dev->kobj, "driver");
 153 }
 154
 155
 156 static ssize_t
 157 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 158                        char * buf)
 159 {
 160         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 161         struct class_device * cd = to_class_dev(kobj);
 162         ssize_t ret = 0;
 163
 164         if (class_dev_attr->show)
 165                 ret = class_dev_attr->show(cd,buf);
 166         return ret;
 167 }
 168
 169 static ssize_t
 170 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 171                         const char * buf, size_t count)
 172 {
 173         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 174         struct class_device * cd = to_class_dev(kobj);
 175         ssize_t ret = 0;
 176
 177         if (class_dev_attr->store)
 178                 ret = class_dev_attr->store(cd,buf,count);
 179         return ret;
 180 }
 181
 182 static struct sysfs_ops class_dev_sysfs_ops = {
 183         .show   = class_device_attr_show,
 184         .store  = class_device_attr_store,
 185 };
 186
 187 static void class_dev_release(struct kobject * kobj)
 188 {
 189         struct class_device *cd = to_class_dev(kobj);
 190         struct class * cls = cd->class;
 191
 192         pr_debug("device class '%s': release.\n",cd->class_id);
 193
 194         if (cls->release)
 195                 cls->release(cd);
 196         else {
 197                 printk(KERN_ERR "Device class '%s' does not have a release() function, "
 198                         "it is broken and must be fixed.\n",
 199                         cd->class_id);
 200                 WARN_ON(1);
 201         }
 202 }
 203
 204 static struct kobj_type ktype_class_device = {
 205         .sysfs_ops      = &class_dev_sysfs_ops,
 206         .release        = class_dev_release,
 207 };
 208
 209 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
 210 {
 211         struct kobj_type *ktype = get_ktype(kobj);
 212
 213         if (ktype == &ktype_class_device) {
 214                 struct class_device *class_dev = to_class_dev(kobj);
 215                 if (class_dev->class)
 216                         return 1;
 217         }
 218         return 0;
 219 }
 220
 221 static char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
 222 {
 223         struct class_device *class_dev = to_class_dev(kobj);
 224
 225         return class_dev->class->name;
 226 }
 227
 228 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 229                          int num_envp, char *buffer, int buffer_size)
 230 {
 231         struct class_device *class_dev = to_class_dev(kobj);
 232         int retval = 0;
 233
 234         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 235         if (class_dev->class->hotplug) {
 236                 /* have the bus specific function add its stuff */
 237                 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
 238                                                     buffer, buffer_size);
 239                         if (retval) {
 240                         pr_debug ("%s - hotplug() returned %d\n",
 241                                   __FUNCTION__, retval);
 242                 }
 243         }
 244
 245         return retval;
 246 }
 247
 248 static struct kset_hotplug_ops class_hotplug_ops = {
 249         .filter =       class_hotplug_filter,
 250         .name =         class_hotplug_name,
 251         .hotplug =      class_hotplug,
 252 };
 253
 254 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
 255
 256 void class_device_initialize(struct class_device *class_dev)
 257 {
 258         kobj_set_kset_s(class_dev, class_obj_subsys);
 259         kobject_init(&class_dev->kobj);
 260         INIT_LIST_HEAD(&class_dev->node);
 261 }
 262
 263 int class_device_add(struct class_device *class_dev)
 264 {
 265         struct class * parent;
 266         struct class_interface * class_intf;
 267         struct list_head * entry;
 268         int error;
 269
 270         class_dev = class_device_get(class_dev);
 271         if (!class_dev || !strlen(class_dev->class_id))
 272                 return -EINVAL;
 273
 274         parent = class_get(class_dev->class);
 275
 276         pr_debug("CLASS: registering class device: ID = '%s'\n",
 277                  class_dev->class_id);
 278
 279         /* first, register with generic layer. */
 280         kobject_set_name(&class_dev->kobj, class_dev->class_id);
 281         if (parent)
 282                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
 283
 284         if ((error = kobject_add(&class_dev->kobj)))
 285                 goto register_done;
 286
 287         /* now take care of our own registration */
 288         if (parent) {
 289                 down_write(&parent->subsys.rwsem);
 290                 list_add_tail(&class_dev->node, &parent->children);
 291                 list_for_each(entry, &parent->interfaces) {
 292                         class_intf = container_of(entry, struct class_interface, node);
 293                         if (class_intf->add)
 294                                 class_intf->add(class_dev);
 295                 }
 296                 up_write(&parent->subsys.rwsem);
 297         }
 298
 299         class_device_dev_link(class_dev);
 300         class_device_driver_link(class_dev);
 301
 302  register_done:
 303         if (error && parent)
 304                 class_put(parent);
 305         class_device_put(class_dev);
 306         return error;
 307 }
 308
 309 int class_device_register(struct class_device *class_dev)
 310 {
 311         class_device_initialize(class_dev);
 312         return class_device_add(class_dev);
 313 }
 314
 315 void class_device_del(struct class_device *class_dev)
 316 {
 317         struct class * parent = class_dev->class;
 318         struct class_interface * class_intf;
 319         struct list_head * entry;
 320
 321         if (parent) {
 322                 down_write(&parent->subsys.rwsem);
 323                 list_del_init(&class_dev->node);
 324                 list_for_each(entry, &parent->interfaces) {
 325                         class_intf = container_of(entry, struct class_interface, node);
 326                         if (class_intf->remove)
 327                                 class_intf->remove(class_dev);
 328                 }
 329                 up_write(&parent->subsys.rwsem);
 330         }
 331
 332         class_device_dev_unlink(class_dev);
 333         class_device_driver_unlink(class_dev);
 334
 335         kobject_del(&class_dev->kobj);
 336
 337         if (parent)
 338                 class_put(parent);
 339 }
 340
 341 void class_device_unregister(struct class_device *class_dev)
 342 {
 343         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 344                  class_dev->class_id);
 345         class_device_del(class_dev);
 346         class_device_put(class_dev);
 347 }
 348
 349 int class_device_rename(struct class_device *class_dev, char *new_name)
 350 {
 351         class_dev = class_device_get(class_dev);
 352         if (!class_dev)
 353                 return -EINVAL;
 354
 355         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
 356                  new_name);
 357
 358         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
 359
 360         kobject_rename(&class_dev->kobj, new_name);
 361
 362         class_device_put(class_dev);
 363
 364         return 0;
 365 }
 366
 367 struct class_device * class_device_get(struct class_device *class_dev)
 368 {
 369         if (class_dev)
 370                 return to_class_dev(kobject_get(&class_dev->kobj));
 371         return NULL;
 372 }
 373
 374 void class_device_put(struct class_device *class_dev)
 375 {
 376         kobject_put(&class_dev->kobj);
 377 }
 378
 379
 380 int class_interface_register(struct class_interface *class_intf)
 381 {
 382         struct class * parent;
 383         struct class_device * class_dev;
 384         struct list_head * entry;
 385
 386         if (!class_intf || !class_intf->class)
 387                 return -ENODEV;
 388
 389         parent = class_get(class_intf->class);
 390         if (!parent)
 391                 return -EINVAL;
 392
 393         down_write(&parent->subsys.rwsem);
 394         list_add_tail(&class_intf->node, &parent->interfaces);
 395
 396         if (class_intf->add) {
 397                 list_for_each(entry, &parent->children) {
 398                         class_dev = container_of(entry, struct class_device, node);
 399                         class_intf->add(class_dev);
 400                 }
 401         }
 402         up_write(&parent->subsys.rwsem);
 403
 404         return 0;
 405 }
 406
 407 void class_interface_unregister(struct class_interface *class_intf)
 408 {
 409         struct class * parent = class_intf->class;
 410         struct list_head * entry;
 411
 412         if (!parent)
 413                 return;
 414
 415         down_write(&parent->subsys.rwsem);
 416         list_del_init(&class_intf->node);
 417
 418         if (class_intf->remove) {
 419                 list_for_each(entry, &parent->children) {
 420                         struct class_device *class_dev = container_of(entry, struct class_device, node);
 421                         class_intf->remove(class_dev);
 422                 }
 423         }
 424         up_write(&parent->subsys.rwsem);
 425
 426         class_put(parent);
 427 }
 428
 429
 430
 431 int __init classes_init(void)
 432 {
 433         int retval;
 434
 435         retval = subsystem_register(&class_subsys);
 436         if (retval)
 437                 return retval;
 438
 439         /* ick, this is ugly, the things we go through to keep from showing up
 440          * in sysfs... */
 441         subsystem_init(&class_obj_subsys);
 442         if (!class_obj_subsys.kset.subsys)
 443                         class_obj_subsys.kset.subsys = &class_obj_subsys;
 444         return 0;
 445 }
 446
 447 EXPORT_SYMBOL(class_create_file);
 448 EXPORT_SYMBOL(class_remove_file);
 449 EXPORT_SYMBOL(class_register);
 450 EXPORT_SYMBOL(class_unregister);
 451 EXPORT_SYMBOL(class_get);
 452 EXPORT_SYMBOL(class_put);
 453
 454 EXPORT_SYMBOL(class_device_register);
 455 EXPORT_SYMBOL(class_device_unregister);
 456 EXPORT_SYMBOL(class_device_initialize);
 457 EXPORT_SYMBOL(class_device_add);
 458 EXPORT_SYMBOL(class_device_del);
 459 EXPORT_SYMBOL(class_device_get);
 460 EXPORT_SYMBOL(class_device_put);
 461 EXPORT_SYMBOL(class_device_create_file);
 462 EXPORT_SYMBOL(class_device_remove_file);
 463
 464 EXPORT_SYMBOL(class_interface_register);
 465 EXPORT_SYMBOL(class_interface_unregister);