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 "base.h"
  19
  20 #define to_class_attr(_attr) container_of(_attr, struct class_attribute, attr)
  21 #define to_class(obj) container_of(obj, struct class, subsys.kset.kobj)
  22
  23 static ssize_t
  24 class_attr_show(struct kobject * kobj, struct attribute * attr, char * buf)
  25 {
  26         struct class_attribute * class_attr = to_class_attr(attr);
  27         struct class * dc = to_class(kobj);
  28         ssize_t ret = 0;
  29
  30         if (class_attr->show)
  31                 ret = class_attr->show(dc, buf);
  32         return ret;
  33 }
  34
  35 static ssize_t
  36 class_attr_store(struct kobject * kobj, struct attribute * attr,
  37                  const char * buf, size_t count)
  38 {
  39         struct class_attribute * class_attr = to_class_attr(attr);
  40         struct class * dc = to_class(kobj);
  41         ssize_t ret = 0;
  42
  43         if (class_attr->store)
  44                 ret = class_attr->store(dc, buf, count);
  45         return ret;
  46 }
  47
  48 static void class_release(struct kobject * kobj)
  49 {
  50         struct class *class = to_class(kobj);
  51
  52         pr_debug("class '%s': release.\n", class->name);
  53
  54         if (class->class_release)
  55                 class->class_release(class);
  56         else
  57                 pr_debug("class '%s' does not have a release() function, "
  58                          "be careful\n", class->name);
  59 }
  60
  61 static struct sysfs_ops class_sysfs_ops = {
  62         .show   = class_attr_show,
  63         .store  = class_attr_store,
  64 };
  65
  66 static struct kobj_type ktype_class = {
  67         .sysfs_ops      = &class_sysfs_ops,
  68         .release        = class_release,
  69 };
  70
  71 /* Hotplug events for classes go to the class_obj subsys */
  72 static decl_subsys(class, &ktype_class, NULL);
  73
  74
  75 int class_create_file(struct class * cls, const struct class_attribute * attr)
  76 {
  77         int error;
  78         if (cls) {
  79                 error = sysfs_create_file(&cls->subsys.kset.kobj, &attr->attr);
  80         } else
  81                 error = -EINVAL;
  82         return error;
  83 }
  84
  85 void class_remove_file(struct class * cls, const struct class_attribute * attr)
  86 {
  87         if (cls)
  88                 sysfs_remove_file(&cls->subsys.kset.kobj, &attr->attr);
  89 }
  90
  91 struct class * class_get(struct class * cls)
  92 {
  93         if (cls)
  94                 return container_of(subsys_get(&cls->subsys), struct class, subsys);
  95         return NULL;
  96 }
  97
  98 void class_put(struct class * cls)
  99 {
 100         subsys_put(&cls->subsys);
 101 }
 102
 103
 104 static int add_class_attrs(struct class * cls)
 105 {
 106         int i;
 107         int error = 0;
 108
 109         if (cls->class_attrs) {
 110                 for (i = 0; attr_name(cls->class_attrs[i]); i++) {
 111                         error = class_create_file(cls,&cls->class_attrs[i]);
 112                         if (error)
 113                                 goto Err;
 114                 }
 115         }
 116  Done:
 117         return error;
 118  Err:
 119         while (--i >= 0)
 120                 class_remove_file(cls,&cls->class_attrs[i]);
 121         goto Done;
 122 }
 123
 124 static void remove_class_attrs(struct class * cls)
 125 {
 126         int i;
 127
 128         if (cls->class_attrs) {
 129                 for (i = 0; attr_name(cls->class_attrs[i]); i++)
 130                         class_remove_file(cls,&cls->class_attrs[i]);
 131         }
 132 }
 133
 134 int class_register(struct class * cls)
 135 {
 136         int error;
 137
 138         pr_debug("device class '%s': registering\n", cls->name);
 139
 140         INIT_LIST_HEAD(&cls->children);
 141         INIT_LIST_HEAD(&cls->interfaces);
 142         error = kobject_set_name(&cls->subsys.kset.kobj, cls->name);
 143         if (error)
 144                 return error;
 145
 146         subsys_set_kset(cls, class_subsys);
 147
 148         error = subsystem_register(&cls->subsys);
 149         if (!error) {
 150                 error = add_class_attrs(class_get(cls));
 151                 class_put(cls);
 152         }
 153         return error;
 154 }
 155
 156 void class_unregister(struct class * cls)
 157 {
 158         pr_debug("device class '%s': unregistering\n", cls->name);
 159         remove_class_attrs(cls);
 160         subsystem_unregister(&cls->subsys);
 161 }
 162
 163
 164 /* Class Device Stuff */
 165
 166 int class_device_create_file(struct class_device * class_dev,
 167                              const struct class_device_attribute * attr)
 168 {
 169         int error = -EINVAL;
 170         if (class_dev)
 171                 error = sysfs_create_file(&class_dev->kobj, &attr->attr);
 172         return error;
 173 }
 174
 175 void class_device_remove_file(struct class_device * class_dev,
 176                               const struct class_device_attribute * attr)
 177 {
 178         if (class_dev)
 179                 sysfs_remove_file(&class_dev->kobj, &attr->attr);
 180 }
 181
 182 static int class_device_dev_link(struct class_device * class_dev)
 183 {
 184         if (class_dev->dev)
 185                 return sysfs_create_link(&class_dev->kobj,
 186                                          &class_dev->dev->kobj, "device");
 187         return 0;
 188 }
 189
 190 static void class_device_dev_unlink(struct class_device * class_dev)
 191 {
 192         sysfs_remove_link(&class_dev->kobj, "device");
 193 }
 194
 195 static int class_device_driver_link(struct class_device * class_dev)
 196 {
 197         if ((class_dev->dev) && (class_dev->dev->driver))
 198                 return sysfs_create_link(&class_dev->kobj,
 199                                          &class_dev->dev->driver->kobj, "driver");
 200         return 0;
 201 }
 202
 203 static void class_device_driver_unlink(struct class_device * class_dev)
 204 {
 205         sysfs_remove_link(&class_dev->kobj, "driver");
 206 }
 207
 208
 209 static ssize_t
 210 class_device_attr_show(struct kobject * kobj, struct attribute * attr,
 211                        char * buf)
 212 {
 213         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 214         struct class_device * cd = to_class_dev(kobj);
 215         ssize_t ret = 0;
 216
 217         if (class_dev_attr->show)
 218                 ret = class_dev_attr->show(cd, buf);
 219         return ret;
 220 }
 221
 222 static ssize_t
 223 class_device_attr_store(struct kobject * kobj, struct attribute * attr,
 224                         const char * buf, size_t count)
 225 {
 226         struct class_device_attribute * class_dev_attr = to_class_dev_attr(attr);
 227         struct class_device * cd = to_class_dev(kobj);
 228         ssize_t ret = 0;
 229
 230         if (class_dev_attr->store)
 231                 ret = class_dev_attr->store(cd, buf, count);
 232         return ret;
 233 }
 234
 235 static struct sysfs_ops class_dev_sysfs_ops = {
 236         .show   = class_device_attr_show,
 237         .store  = class_device_attr_store,
 238 };
 239
 240 static void class_dev_release(struct kobject * kobj)
 241 {
 242         struct class_device *cd = to_class_dev(kobj);
 243         struct class * cls = cd->class;
 244
 245         pr_debug("device class '%s': release.\n", cd->class_id);
 246
 247         if (cls->release)
 248                 cls->release(cd);
 249         else {
 250                 printk(KERN_ERR "Device class '%s' does not have a release() function, "
 251                         "it is broken and must be fixed.\n",
 252                         cd->class_id);
 253                 WARN_ON(1);
 254         }
 255 }
 256
 257 static struct kobj_type ktype_class_device = {
 258         .sysfs_ops      = &class_dev_sysfs_ops,
 259         .release        = class_dev_release,
 260 };
 261
 262 static int class_hotplug_filter(struct kset *kset, struct kobject *kobj)
 263 {
 264         struct kobj_type *ktype = get_ktype(kobj);
 265
 266         if (ktype == &ktype_class_device) {
 267                 struct class_device *class_dev = to_class_dev(kobj);
 268                 if (class_dev->class)
 269                         return 1;
 270         }
 271         return 0;
 272 }
 273
 274 static char *class_hotplug_name(struct kset *kset, struct kobject *kobj)
 275 {
 276         struct class_device *class_dev = to_class_dev(kobj);
 277
 278         return class_dev->class->name;
 279 }
 280
 281 static int class_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
 282                          int num_envp, char *buffer, int buffer_size)
 283 {
 284         struct class_device *class_dev = to_class_dev(kobj);
 285         int retval = 0;
 286
 287         pr_debug("%s - name = %s\n", __FUNCTION__, class_dev->class_id);
 288         if (class_dev->class->hotplug) {
 289                 /* have the bus specific function add its stuff */
 290                 retval = class_dev->class->hotplug (class_dev, envp, num_envp,
 291                                                     buffer, buffer_size);
 292                         if (retval) {
 293                         pr_debug ("%s - hotplug() returned %d\n",
 294                                   __FUNCTION__, retval);
 295                 }
 296         }
 297
 298         return retval;
 299 }
 300
 301 static struct kset_hotplug_ops class_hotplug_ops = {
 302         .filter =       class_hotplug_filter,
 303         .name =         class_hotplug_name,
 304         .hotplug =      class_hotplug,
 305 };
 306
 307 static decl_subsys(class_obj, &ktype_class_device, &class_hotplug_ops);
 308
 309
 310 static int class_device_add_attrs(struct class_device * cd)
 311 {
 312         int i;
 313         int error = 0;
 314         struct class * cls = cd->class;
 315
 316         if (cls->class_dev_attrs) {
 317                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++) {
 318                         error = class_device_create_file(cd,
 319                                                          &cls->class_dev_attrs[i]);
 320                         if (error)
 321                                 goto Err;
 322                 }
 323         }
 324  Done:
 325         return error;
 326  Err:
 327         while (--i >= 0)
 328                 class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 329         goto Done;
 330 }
 331
 332 static void class_device_remove_attrs(struct class_device * cd)
 333 {
 334         int i;
 335         struct class * cls = cd->class;
 336
 337         if (cls->class_dev_attrs) {
 338                 for (i = 0; attr_name(cls->class_dev_attrs[i]); i++)
 339                         class_device_remove_file(cd,&cls->class_dev_attrs[i]);
 340         }
 341 }
 342
 343 void class_device_initialize(struct class_device *class_dev)
 344 {
 345         kobj_set_kset_s(class_dev, class_obj_subsys);
 346         kobject_init(&class_dev->kobj);
 347         INIT_LIST_HEAD(&class_dev->node);
 348 }
 349
 350 int class_device_add(struct class_device *class_dev)
 351 {
 352         struct class * parent;
 353         struct class_interface * class_intf;
 354         int error;
 355
 356         class_dev = class_device_get(class_dev);
 357         if (!class_dev || !strlen(class_dev->class_id))
 358                 return -EINVAL;
 359
 360         parent = class_get(class_dev->class);
 361
 362         pr_debug("CLASS: registering class device: ID = '%s'\n",
 363                  class_dev->class_id);
 364
 365         /* first, register with generic layer. */
 366         kobject_set_name(&class_dev->kobj, class_dev->class_id);
 367         if (parent)
 368                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
 369
 370         if ((error = kobject_add(&class_dev->kobj)))
 371                 goto register_done;
 372
 373         /* now take care of our own registration */
 374         if (parent) {
 375                 down_write(&parent->subsys.rwsem);
 376                 list_add_tail(&class_dev->node, &parent->children);
 377                 list_for_each_entry(class_intf, &parent->interfaces, node)
 378                         if (class_intf->add)
 379                                 class_intf->add(class_dev);
 380                 up_write(&parent->subsys.rwsem);
 381         }
 382         class_device_add_attrs(class_dev);
 383         class_device_dev_link(class_dev);
 384         class_device_driver_link(class_dev);
 385
 386  register_done:
 387         if (error && parent)
 388                 class_put(parent);
 389         class_device_put(class_dev);
 390         return error;
 391 }
 392
 393 int class_device_register(struct class_device *class_dev)
 394 {
 395         class_device_initialize(class_dev);
 396         return class_device_add(class_dev);
 397 }
 398
 399 void class_device_del(struct class_device *class_dev)
 400 {
 401         struct class * parent = class_dev->class;
 402         struct class_interface * class_intf;
 403
 404         if (parent) {
 405                 down_write(&parent->subsys.rwsem);
 406                 list_del_init(&class_dev->node);
 407                 list_for_each_entry(class_intf, &parent->interfaces, node)
 408                         if (class_intf->remove)
 409                                 class_intf->remove(class_dev);
 410                 up_write(&parent->subsys.rwsem);
 411         }
 412
 413         class_device_dev_unlink(class_dev);
 414         class_device_driver_unlink(class_dev);
 415         class_device_remove_attrs(class_dev);
 416
 417         kobject_del(&class_dev->kobj);
 418
 419         if (parent)
 420                 class_put(parent);
 421 }
 422
 423 void class_device_unregister(struct class_device *class_dev)
 424 {
 425         pr_debug("CLASS: Unregistering class device. ID = '%s'\n",
 426                  class_dev->class_id);
 427         class_device_del(class_dev);
 428         class_device_put(class_dev);
 429 }
 430
 431 int class_device_rename(struct class_device *class_dev, char *new_name)
 432 {
 433         int error = 0;
 434
 435         class_dev = class_device_get(class_dev);
 436         if (!class_dev)
 437                 return -EINVAL;
 438
 439         pr_debug("CLASS: renaming '%s' to '%s'\n", class_dev->class_id,
 440                  new_name);
 441
 442         strlcpy(class_dev->class_id, new_name, KOBJ_NAME_LEN);
 443
 444         error = kobject_rename(&class_dev->kobj, new_name);
 445
 446         class_device_put(class_dev);
 447
 448         return error;
 449 }
 450
 451 struct class_device * class_device_get(struct class_device *class_dev)
 452 {
 453         if (class_dev)
 454                 return to_class_dev(kobject_get(&class_dev->kobj));
 455         return NULL;
 456 }
 457
 458 void class_device_put(struct class_device *class_dev)
 459 {
 460         kobject_put(&class_dev->kobj);
 461 }
 462
 463
 464 int class_interface_register(struct class_interface *class_intf)
 465 {
 466         struct class * parent;
 467         struct class_device * class_dev;
 468
 469         if (!class_intf || !class_intf->class)
 470                 return -ENODEV;
 471
 472         parent = class_get(class_intf->class);
 473         if (!parent)
 474                 return -EINVAL;
 475
 476         down_write(&parent->subsys.rwsem);
 477         list_add_tail(&class_intf->node, &parent->interfaces);
 478
 479         if (class_intf->add) {
 480                 list_for_each_entry(class_dev, &parent->children, node)
 481                         class_intf->add(class_dev);
 482         }
 483         up_write(&parent->subsys.rwsem);
 484
 485         return 0;
 486 }
 487
 488 void class_interface_unregister(struct class_interface *class_intf)
 489 {
 490         struct class * parent = class_intf->class;
 491         struct class_device *class_dev;
 492
 493         if (!parent)
 494                 return;
 495
 496         down_write(&parent->subsys.rwsem);
 497         list_del_init(&class_intf->node);
 498
 499         if (class_intf->remove) {
 500                 list_for_each_entry(class_dev, &parent->children, node)
 501                         class_intf->remove(class_dev);
 502         }
 503         up_write(&parent->subsys.rwsem);
 504
 505         class_put(parent);
 506 }
 507
 508
 509
 510 int __init classes_init(void)
 511 {
 512         int retval;
 513
 514         retval = subsystem_register(&class_subsys);
 515         if (retval)
 516                 return retval;
 517
 518         /* ick, this is ugly, the things we go through to keep from showing up
 519          * in sysfs... */
 520         subsystem_init(&class_obj_subsys);
 521         if (!class_obj_subsys.kset.subsys)
 522                         class_obj_subsys.kset.subsys = &class_obj_subsys;
 523         return 0;
 524 }
 525
 526 EXPORT_SYMBOL(class_create_file);
 527 EXPORT_SYMBOL(class_remove_file);
 528 EXPORT_SYMBOL(class_register);
 529 EXPORT_SYMBOL(class_unregister);
 530 EXPORT_SYMBOL(class_get);
 531 EXPORT_SYMBOL(class_put);
 532
 533 EXPORT_SYMBOL(class_device_register);
 534 EXPORT_SYMBOL(class_device_unregister);
 535 EXPORT_SYMBOL(class_device_initialize);
 536 EXPORT_SYMBOL(class_device_add);
 537 EXPORT_SYMBOL(class_device_del);
 538 EXPORT_SYMBOL(class_device_get);
 539 EXPORT_SYMBOL(class_device_put);
 540 EXPORT_SYMBOL(class_device_create_file);
 541 EXPORT_SYMBOL(class_device_remove_file);
 542
 543 EXPORT_SYMBOL(class_interface_register);
 544 EXPORT_SYMBOL(class_interface_unregister);