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   1 /* i2c-core.c - a device driver for the iic-bus interface                    */
   2 /* ------------------------------------------------------------------------- */
   3 /*   Copyright (C) 1995-99 Simon G. Vogl
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                */
  18 /* ------------------------------------------------------------------------- */
  19
  20 /* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
  21    All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
  22    SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com>                */
  23
  24 #include <linux/module.h>
  25 #include <linux/kernel.h>
  26 #include <linux/errno.h>
  27 #include <linux/slab.h>
  28 #include <linux/i2c.h>
  29 #include <linux/init.h>
  30 #include <linux/idr.h>
  31 #include <linux/seq_file.h>
  32 #include <asm/uaccess.h>
  33
  34
  35 static LIST_HEAD(adapters);
  36 static LIST_HEAD(drivers);
  37 static DECLARE_MUTEX(core_lists);
  38 static DEFINE_IDR(i2c_adapter_idr);
  39
  40 /* match always succeeds, as we want the probe() to tell if we really accept this match */
  41 static int i2c_device_match(struct device *dev, struct device_driver *drv)
  42 {
  43         return 1;
  44 }
  45
  46 static int i2c_bus_suspend(struct device * dev, pm_message_t state)
  47 {
  48         int rc = 0;
  49
  50         if (dev->driver && dev->driver->suspend)
  51                 rc = dev->driver->suspend(dev,state,0);
  52         return rc;
  53 }
  54
  55 static int i2c_bus_resume(struct device * dev)
  56 {
  57         int rc = 0;
  58
  59         if (dev->driver && dev->driver->resume)
  60                 rc = dev->driver->resume(dev,0);
  61         return rc;
  62 }
  63
  64 static struct bus_type i2c_bus_type = {
  65         .name =         "i2c",
  66         .match =        i2c_device_match,
  67         .suspend =      i2c_bus_suspend,
  68         .resume =       i2c_bus_resume,
  69 };
  70
  71 static int i2c_device_probe(struct device *dev)
  72 {
  73         return -ENODEV;
  74 }
  75
  76 static int i2c_device_remove(struct device *dev)
  77 {
  78         return 0;
  79 }
  80
  81 static void i2c_adapter_dev_release(struct device *dev)
  82 {
  83         struct i2c_adapter *adap = dev_to_i2c_adapter(dev);
  84         complete(&adap->dev_released);
  85 }
  86
  87 static struct device_driver i2c_adapter_driver = {
  88         .name = "i2c_adapter",
  89         .bus = &i2c_bus_type,
  90         .probe = i2c_device_probe,
  91         .remove = i2c_device_remove,
  92 };
  93
  94 static void i2c_adapter_class_dev_release(struct class_device *dev)
  95 {
  96         struct i2c_adapter *adap = class_dev_to_i2c_adapter(dev);
  97         complete(&adap->class_dev_released);
  98 }
  99
 100 static struct class i2c_adapter_class = {
 101         .name =         "i2c-adapter",
 102         .release =      &i2c_adapter_class_dev_release,
 103 };
 104
 105 static ssize_t show_adapter_name(struct device *dev, struct device_attribute *attr, char *buf)
 106 {
 107         struct i2c_adapter *adap = dev_to_i2c_adapter(dev);
 108         return sprintf(buf, "%s\n", adap->name);
 109 }
 110 static DEVICE_ATTR(name, S_IRUGO, show_adapter_name, NULL);
 111
 112
 113 static void i2c_client_release(struct device *dev)
 114 {
 115         struct i2c_client *client = to_i2c_client(dev);
 116         complete(&client->released);
 117 }
 118
 119 static ssize_t show_client_name(struct device *dev, struct device_attribute *attr, char *buf)
 120 {
 121         struct i2c_client *client = to_i2c_client(dev);
 122         return sprintf(buf, "%s\n", client->name);
 123 }
 124
 125 /*
 126  * We can't use the DEVICE_ATTR() macro here as we want the same filename for a
 127  * different type of a device.  So beware if the DEVICE_ATTR() macro ever
 128  * changes, this definition will also have to change.
 129  */
 130 static struct device_attribute dev_attr_client_name = {
 131         .attr   = {.name = "name", .mode = S_IRUGO, .owner = THIS_MODULE },
 132         .show   = &show_client_name,
 133 };
 134
 135
 136 /* ---------------------------------------------------
 137  * registering functions
 138  * ---------------------------------------------------
 139  */
 140
 141 /* -----
 142  * i2c_add_adapter is called from within the algorithm layer,
 143  * when a new hw adapter registers. A new device is register to be
 144  * available for clients.
 145  */
 146 int i2c_add_adapter(struct i2c_adapter *adap)
 147 {
 148         int id, res = 0;
 149         struct list_head   *item;
 150         struct i2c_driver  *driver;
 151
 152         down(&core_lists);
 153
 154         if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) {
 155                 res = -ENOMEM;
 156                 goto out_unlock;
 157         }
 158
 159         res = idr_get_new(&i2c_adapter_idr, NULL, &id);
 160         if (res < 0) {
 161                 if (res == -EAGAIN)
 162                         res = -ENOMEM;
 163                 goto out_unlock;
 164         }
 165
 166         adap->nr =  id & MAX_ID_MASK;
 167         init_MUTEX(&adap->bus_lock);
 168         init_MUTEX(&adap->clist_lock);
 169         list_add_tail(&adap->list,&adapters);
 170         INIT_LIST_HEAD(&adap->clients);
 171
 172         /* Add the adapter to the driver core.
 173          * If the parent pointer is not set up,
 174          * we add this adapter to the host bus.
 175          */
 176         if (adap->dev.parent == NULL)
 177                 adap->dev.parent = &platform_bus;
 178         sprintf(adap->dev.bus_id, "i2c-%d", adap->nr);
 179         adap->dev.driver = &i2c_adapter_driver;
 180         adap->dev.release = &i2c_adapter_dev_release;
 181         device_register(&adap->dev);
 182         device_create_file(&adap->dev, &dev_attr_name);
 183
 184         /* Add this adapter to the i2c_adapter class */
 185         memset(&adap->class_dev, 0x00, sizeof(struct class_device));
 186         adap->class_dev.dev = &adap->dev;
 187         adap->class_dev.class = &i2c_adapter_class;
 188         strlcpy(adap->class_dev.class_id, adap->dev.bus_id, BUS_ID_SIZE);
 189         class_device_register(&adap->class_dev);
 190
 191         /* inform drivers of new adapters */
 192         list_for_each(item,&drivers) {
 193                 driver = list_entry(item, struct i2c_driver, list);
 194                 if (driver->flags & I2C_DF_NOTIFY)
 195                         /* We ignore the return code; if it fails, too bad */
 196                         driver->attach_adapter(adap);
 197         }
 198
 199         dev_dbg(&adap->dev, "registered as adapter #%d\n", adap->nr);
 200
 201 out_unlock:
 202         up(&core_lists);
 203         return res;
 204 }
 205
 206
 207 int i2c_del_adapter(struct i2c_adapter *adap)
 208 {
 209         struct list_head  *item, *_n;
 210         struct i2c_adapter *adap_from_list;
 211         struct i2c_driver *driver;
 212         struct i2c_client *client;
 213         int res = 0;
 214
 215         down(&core_lists);
 216
 217         /* First make sure that this adapter was ever added */
 218         list_for_each_entry(adap_from_list, &adapters, list) {
 219                 if (adap_from_list == adap)
 220                         break;
 221         }
 222         if (adap_from_list != adap) {
 223                 pr_debug("I2C: Attempting to delete an unregistered "
 224                          "adapter\n");
 225                 res = -EINVAL;
 226                 goto out_unlock;
 227         }
 228
 229         list_for_each(item,&drivers) {
 230                 driver = list_entry(item, struct i2c_driver, list);
 231                 if (driver->detach_adapter)
 232                         if ((res = driver->detach_adapter(adap))) {
 233                                 dev_warn(&adap->dev, "can't detach adapter "
 234                                          "while detaching driver %s: driver not "
 235                                          "detached!", driver->name);
 236                                 goto out_unlock;
 237                         }
 238         }
 239
 240         /* detach any active clients. This must be done first, because
 241          * it can fail; in which case we give up. */
 242         list_for_each_safe(item, _n, &adap->clients) {
 243                 client = list_entry(item, struct i2c_client, list);
 244
 245                 /* detaching devices is unconditional of the set notify
 246                  * flag, as _all_ clients that reside on the adapter
 247                  * must be deleted, as this would cause invalid states.
 248                  */
 249                 if ((res=client->driver->detach_client(client))) {
 250                         dev_err(&adap->dev, "adapter not "
 251                                 "unregistered, because client at "
 252                                 "address %02x can't be detached. ",
 253                                 client->addr);
 254                         goto out_unlock;
 255                 }
 256         }
 257
 258         /* clean up the sysfs representation */
 259         init_completion(&adap->dev_released);
 260         init_completion(&adap->class_dev_released);
 261         class_device_unregister(&adap->class_dev);
 262         device_remove_file(&adap->dev, &dev_attr_name);
 263         device_unregister(&adap->dev);
 264         list_del(&adap->list);
 265
 266         /* wait for sysfs to drop all references */
 267         wait_for_completion(&adap->dev_released);
 268         wait_for_completion(&adap->class_dev_released);
 269
 270         /* free dynamically allocated bus id */
 271         idr_remove(&i2c_adapter_idr, adap->nr);
 272
 273         dev_dbg(&adap->dev, "adapter unregistered\n");
 274
 275  out_unlock:
 276         up(&core_lists);
 277         return res;
 278 }
 279
 280
 281 /* -----
 282  * What follows is the "upwards" interface: commands for talking to clients,
 283  * which implement the functions to access the physical information of the
 284  * chips.
 285  */
 286
 287 int i2c_add_driver(struct i2c_driver *driver)
 288 {
 289         struct list_head   *item;
 290         struct i2c_adapter *adapter;
 291         int res = 0;
 292
 293         down(&core_lists);
 294
 295         /* add the driver to the list of i2c drivers in the driver core */
 296         driver->driver.name = driver->name;
 297         driver->driver.bus = &i2c_bus_type;
 298         driver->driver.probe = i2c_device_probe;
 299         driver->driver.remove = i2c_device_remove;
 300
 301         res = driver_register(&driver->driver);
 302         if (res)
 303                 goto out_unlock;
 304
 305         list_add_tail(&driver->list,&drivers);
 306         pr_debug("i2c-core: driver %s registered.\n", driver->name);
 307
 308         /* now look for instances of driver on our adapters */
 309         if (driver->flags & I2C_DF_NOTIFY) {
 310                 list_for_each(item,&adapters) {
 311                         adapter = list_entry(item, struct i2c_adapter, list);
 312                         driver->attach_adapter(adapter);
 313                 }
 314         }
 315
 316  out_unlock:
 317         up(&core_lists);
 318         return res;
 319 }
 320
 321 int i2c_del_driver(struct i2c_driver *driver)
 322 {
 323         struct list_head   *item1, *item2, *_n;
 324         struct i2c_client  *client;
 325         struct i2c_adapter *adap;
 326
 327         int res = 0;
 328
 329         down(&core_lists);
 330
 331         /* Have a look at each adapter, if clients of this driver are still
 332          * attached. If so, detach them to be able to kill the driver
 333          * afterwards.
 334          */
 335         pr_debug("i2c-core: unregister_driver - looking for clients.\n");
 336         /* removing clients does not depend on the notify flag, else
 337          * invalid operation might (will!) result, when using stale client
 338          * pointers.
 339          */
 340         list_for_each(item1,&adapters) {
 341                 adap = list_entry(item1, struct i2c_adapter, list);
 342                 dev_dbg(&adap->dev, "examining adapter\n");
 343                 if (driver->detach_adapter) {
 344                         if ((res = driver->detach_adapter(adap))) {
 345                                 dev_warn(&adap->dev, "while unregistering "
 346                                        "dummy driver %s, adapter could "
 347                                        "not be detached properly; driver "
 348                                        "not unloaded!",driver->name);
 349                                 goto out_unlock;
 350                         }
 351                 } else {
 352                         list_for_each_safe(item2, _n, &adap->clients) {
 353                                 client = list_entry(item2, struct i2c_client, list);
 354                                 if (client->driver != driver)
 355                                         continue;
 356                                 pr_debug("i2c-core.o: detaching client %s:\n", client->name);
 357                                 if ((res = driver->detach_client(client))) {
 358                                         dev_err(&adap->dev, "while "
 359                                                 "unregistering driver "
 360                                                 "`%s', the client at "
 361                                                 "address %02x of "
 362                                                 "adapter could not "
 363                                                 "be detached; driver "
 364                                                 "not unloaded!",
 365                                                 driver->name,
 366                                                 client->addr);
 367                                         goto out_unlock;
 368                                 }
 369                         }
 370                 }
 371         }
 372
 373         driver_unregister(&driver->driver);
 374         list_del(&driver->list);
 375         pr_debug("i2c-core: driver unregistered: %s\n", driver->name);
 376
 377  out_unlock:
 378         up(&core_lists);
 379         return 0;
 380 }
 381
 382 static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 383 {
 384         struct list_head   *item;
 385         struct i2c_client  *client;
 386
 387         list_for_each(item,&adapter->clients) {
 388                 client = list_entry(item, struct i2c_client, list);
 389                 if (client->addr == addr)
 390                         return -EBUSY;
 391         }
 392         return 0;
 393 }
 394
 395 int i2c_check_addr(struct i2c_adapter *adapter, int addr)
 396 {
 397         int rval;
 398
 399         down(&adapter->clist_lock);
 400         rval = __i2c_check_addr(adapter, addr);
 401         up(&adapter->clist_lock);
 402
 403         return rval;
 404 }
 405
 406 int i2c_attach_client(struct i2c_client *client)
 407 {
 408         struct i2c_adapter *adapter = client->adapter;
 409
 410         down(&adapter->clist_lock);
 411         if (__i2c_check_addr(client->adapter, client->addr)) {
 412                 up(&adapter->clist_lock);
 413                 return -EBUSY;
 414         }
 415         list_add_tail(&client->list,&adapter->clients);
 416         up(&adapter->clist_lock);
 417
 418         if (adapter->client_register)  {
 419                 if (adapter->client_register(client))  {
 420                         dev_warn(&adapter->dev, "warning: client_register "
 421                                 "seems to have failed for client %02x\n",
 422                                 client->addr);
 423                 }
 424         }
 425
 426         dev_dbg(&adapter->dev, "client [%s] registered to adapter\n",
 427                 client->name);
 428
 429         if (client->flags & I2C_CLIENT_ALLOW_USE)
 430                 client->usage_count = 0;
 431
 432         client->dev.parent = &client->adapter->dev;
 433         client->dev.driver = &client->driver->driver;
 434         client->dev.bus = &i2c_bus_type;
 435         client->dev.release = &i2c_client_release;
 436
 437         snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),
 438                 "%d-%04x", i2c_adapter_id(adapter), client->addr);
 439         pr_debug("registering %s\n", client->dev.bus_id);
 440         device_register(&client->dev);
 441         device_create_file(&client->dev, &dev_attr_client_name);
 442
 443         return 0;
 444 }
 445
 446
 447 int i2c_detach_client(struct i2c_client *client)
 448 {
 449         struct i2c_adapter *adapter = client->adapter;
 450         int res = 0;
 451
 452         if ((client->flags & I2C_CLIENT_ALLOW_USE) && (client->usage_count > 0))
 453                 return -EBUSY;
 454
 455         if (adapter->client_unregister)  {
 456                 res = adapter->client_unregister(client);
 457                 if (res) {
 458                         dev_err(&client->dev,
 459                                "client_unregister [%s] failed, "
 460                                "client not detached", client->name);
 461                         goto out;
 462                 }
 463         }
 464
 465         down(&adapter->clist_lock);
 466         list_del(&client->list);
 467         init_completion(&client->released);
 468         device_remove_file(&client->dev, &dev_attr_client_name);
 469         device_unregister(&client->dev);
 470         up(&adapter->clist_lock);
 471         wait_for_completion(&client->released);
 472
 473  out:
 474         return res;
 475 }
 476
 477 static int i2c_inc_use_client(struct i2c_client *client)
 478 {
 479
 480         if (!try_module_get(client->driver->owner))
 481                 return -ENODEV;
 482         if (!try_module_get(client->adapter->owner)) {
 483                 module_put(client->driver->owner);
 484                 return -ENODEV;
 485         }
 486
 487         return 0;
 488 }
 489
 490 static void i2c_dec_use_client(struct i2c_client *client)
 491 {
 492         module_put(client->driver->owner);
 493         module_put(client->adapter->owner);
 494 }
 495
 496 int i2c_use_client(struct i2c_client *client)
 497 {
 498         int ret;
 499
 500         ret = i2c_inc_use_client(client);
 501         if (ret)
 502                 return ret;
 503
 504         if (client->flags & I2C_CLIENT_ALLOW_USE) {
 505                 if (client->flags & I2C_CLIENT_ALLOW_MULTIPLE_USE)
 506                         client->usage_count++;
 507                 else if (client->usage_count > 0)
 508                         goto busy;
 509                 else
 510                         client->usage_count++;
 511         }
 512
 513         return 0;
 514  busy:
 515         i2c_dec_use_client(client);
 516         return -EBUSY;
 517 }
 518
 519 int i2c_release_client(struct i2c_client *client)
 520 {
 521         if(client->flags & I2C_CLIENT_ALLOW_USE) {
 522                 if(client->usage_count>0)
 523                         client->usage_count--;
 524                 else {
 525                         pr_debug("i2c-core: %s used one too many times\n",
 526                                 __FUNCTION__);
 527                         return -EPERM;
 528                 }
 529         }
 530
 531         i2c_dec_use_client(client);
 532
 533         return 0;
 534 }
 535
 536 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
 537 {
 538         struct list_head  *item;
 539         struct i2c_client *client;
 540
 541         down(&adap->clist_lock);
 542         list_for_each(item,&adap->clients) {
 543                 client = list_entry(item, struct i2c_client, list);
 544                 if (!try_module_get(client->driver->owner))
 545                         continue;
 546                 if (NULL != client->driver->command) {
 547                         up(&adap->clist_lock);
 548                         client->driver->command(client,cmd,arg);
 549                         down(&adap->clist_lock);
 550                 }
 551                 module_put(client->driver->owner);
 552        }
 553        up(&adap->clist_lock);
 554 }
 555
 556 static int __init i2c_init(void)
 557 {
 558         int retval;
 559
 560         retval = bus_register(&i2c_bus_type);
 561         if (retval)
 562                 return retval;
 563         retval = driver_register(&i2c_adapter_driver);
 564         if (retval)
 565                 return retval;
 566         return class_register(&i2c_adapter_class);
 567 }
 568
 569 static void __exit i2c_exit(void)
 570 {
 571         class_unregister(&i2c_adapter_class);
 572         driver_unregister(&i2c_adapter_driver);
 573         bus_unregister(&i2c_bus_type);
 574 }
 575
 576 subsys_initcall(i2c_init);
 577 module_exit(i2c_exit);
 578
 579 /* ----------------------------------------------------
 580  * the functional interface to the i2c busses.
 581  * ----------------------------------------------------
 582  */
 583
 584 int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
 585 {
 586         int ret;
 587
 588         if (adap->algo->master_xfer) {
 589 #ifdef DEBUG
 590                 for (ret = 0; ret < num; ret++) {
 591                         dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
 592                                 "len=%d\n", ret, msgs[ret].flags & I2C_M_RD ?
 593                                 'R' : 'W', msgs[ret].addr, msgs[ret].len);
 594                 }
 595 #endif
 596
 597                 down(&adap->bus_lock);
 598                 ret = adap->algo->master_xfer(adap,msgs,num);
 599                 up(&adap->bus_lock);
 600
 601                 return ret;
 602         } else {
 603                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
 604                 return -ENOSYS;
 605         }
 606 }
 607
 608 int i2c_master_send(struct i2c_client *client,const char *buf ,int count)
 609 {
 610         int ret;
 611         struct i2c_adapter *adap=client->adapter;
 612         struct i2c_msg msg;
 613
 614         msg.addr = client->addr;
 615         msg.flags = client->flags & I2C_M_TEN;
 616         msg.len = count;
 617         msg.buf = (char *)buf;
 618
 619         ret = i2c_transfer(adap, &msg, 1);
 620
 621         /* If everything went ok (i.e. 1 msg transmitted), return #bytes
 622            transmitted, else error code. */
 623         return (ret == 1) ? count : ret;
 624 }
 625
 626 int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
 627 {
 628         struct i2c_adapter *adap=client->adapter;
 629         struct i2c_msg msg;
 630         int ret;
 631
 632         msg.addr = client->addr;
 633         msg.flags = client->flags & I2C_M_TEN;
 634         msg.flags |= I2C_M_RD;
 635         msg.len = count;
 636         msg.buf = buf;
 637
 638         ret = i2c_transfer(adap, &msg, 1);
 639
 640         /* If everything went ok (i.e. 1 msg transmitted), return #bytes
 641            transmitted, else error code. */
 642         return (ret == 1) ? count : ret;
 643 }
 644
 645
 646 int i2c_control(struct i2c_client *client,
 647         unsigned int cmd, unsigned long arg)
 648 {
 649         int ret = 0;
 650         struct i2c_adapter *adap = client->adapter;
 651
 652         dev_dbg(&client->adapter->dev, "i2c ioctl, cmd: 0x%x, arg: %#lx\n", cmd, arg);
 653         switch (cmd) {
 654                 case I2C_RETRIES:
 655                         adap->retries = arg;
 656                         break;
 657                 case I2C_TIMEOUT:
 658                         adap->timeout = arg;
 659                         break;
 660                 default:
 661                         if (adap->algo->algo_control!=NULL)
 662                                 ret = adap->algo->algo_control(adap,cmd,arg);
 663         }
 664         return ret;
 665 }
 666
 667 /* ----------------------------------------------------
 668  * the i2c address scanning function
 669  * Will not work for 10-bit addresses!
 670  * ----------------------------------------------------
 671  */
 672 int i2c_probe(struct i2c_adapter *adapter,
 673               struct i2c_client_address_data *address_data,
 674               int (*found_proc) (struct i2c_adapter *, int, int))
 675 {
 676         int addr,i,found,err;
 677         int adap_id = i2c_adapter_id(adapter);
 678
 679         /* Forget it if we can't probe using SMBUS_QUICK */
 680         if (! i2c_check_functionality(adapter,I2C_FUNC_SMBUS_QUICK))
 681                 return -1;
 682
 683         for (addr = 0x00; addr <= 0x7f; addr++) {
 684
 685                 /* Skip if already in use */
 686                 if (i2c_check_addr(adapter,addr))
 687                         continue;
 688
 689                 /* If it is in one of the force entries, we don't do any detection
 690                    at all */
 691                 found = 0;
 692
 693                 for (i = 0; !found && (address_data->force[i] != I2C_CLIENT_END); i += 2) {
 694                         if (((adap_id == address_data->force[i]) ||
 695                              (address_data->force[i] == ANY_I2C_BUS)) &&
 696                              (addr == address_data->force[i+1])) {
 697                                 dev_dbg(&adapter->dev, "found force parameter for adapter %d, addr %04x\n",
 698                                         adap_id, addr);
 699                                 if ((err = found_proc(adapter,addr,0)))
 700                                         return err;
 701                                 found = 1;
 702                         }
 703                 }
 704                 if (found)
 705                         continue;
 706
 707                 /* If this address is in one of the ignores, we can forget about
 708                    it right now */
 709                 for (i = 0;
 710                      !found && (address_data->ignore[i] != I2C_CLIENT_END);
 711                      i += 2) {
 712                         if (((adap_id == address_data->ignore[i]) ||
 713                             ((address_data->ignore[i] == ANY_I2C_BUS))) &&
 714                             (addr == address_data->ignore[i+1])) {
 715                                 dev_dbg(&adapter->dev, "found ignore parameter for adapter %d, "
 716                                         "addr %04x\n", adap_id ,addr);
 717                                 found = 1;
 718                         }
 719                 }
 720                 if (found)
 721                         continue;
 722
 723                 /* Now, we will do a detection, but only if it is in the normal or
 724                    probe entries */
 725                 for (i = 0;
 726                      !found && (address_data->normal_i2c[i] != I2C_CLIENT_END);
 727                      i += 1) {
 728                         if (addr == address_data->normal_i2c[i]) {
 729                                 found = 1;
 730                                 dev_dbg(&adapter->dev, "found normal i2c entry for adapter %d, "
 731                                         "addr %02x\n", adap_id, addr);
 732                         }
 733                 }
 734
 735                 for (i = 0;
 736                      !found && (address_data->probe[i] != I2C_CLIENT_END);
 737                      i += 2) {
 738                         if (((adap_id == address_data->probe[i]) ||
 739                             ((address_data->probe[i] == ANY_I2C_BUS))) &&
 740                             (addr == address_data->probe[i+1])) {
 741                                 found = 1;
 742                                 dev_dbg(&adapter->dev, "found probe parameter for adapter %d, "
 743                                         "addr %04x\n", adap_id,addr);
 744                         }
 745                 }
 746                 if (!found)
 747                         continue;
 748
 749                 /* OK, so we really should examine this address. First check
 750                    whether there is some client here at all! */
 751                 if (i2c_smbus_xfer(adapter,addr,0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)
 752                         if ((err = found_proc(adapter,addr,-1)))
 753                                 return err;
 754         }
 755         return 0;
 756 }
 757
 758 /*
 759  * return id number for a specific adapter
 760  */
 761 int i2c_adapter_id(struct i2c_adapter *adap)
 762 {
 763         return adap->nr;
 764 }
 765
 766 struct i2c_adapter* i2c_get_adapter(int id)
 767 {
 768         struct list_head   *item;
 769         struct i2c_adapter *adapter;
 770
 771         down(&core_lists);
 772         list_for_each(item,&adapters) {
 773                 adapter = list_entry(item, struct i2c_adapter, list);
 774                 if (id == adapter->nr &&
 775                     try_module_get(adapter->owner)) {
 776                         up(&core_lists);
 777                         return adapter;
 778                 }
 779         }
 780         up(&core_lists);
 781         return NULL;
 782 }
 783
 784 void i2c_put_adapter(struct i2c_adapter *adap)
 785 {
 786         module_put(adap->owner);
 787 }
 788
 789 /* The SMBus parts */
 790
 791 #define POLY    (0x1070U << 3)
 792 static u8
 793 crc8(u16 data)
 794 {
 795         int i;
 796
 797         for(i = 0; i < 8; i++) {
 798                 if (data & 0x8000)
 799                         data = data ^ POLY;
 800                 data = data << 1;
 801         }
 802         return (u8)(data >> 8);
 803 }
 804
 805 /* CRC over count bytes in the first array plus the bytes in the rest
 806    array if it is non-null. rest[0] is the (length of rest) - 1
 807    and is included. */
 808 static u8 i2c_smbus_partial_pec(u8 crc, int count, u8 *first, u8 *rest)
 809 {
 810         int i;
 811
 812         for(i = 0; i < count; i++)
 813                 crc = crc8((crc ^ first[i]) << 8);
 814         if(rest != NULL)
 815                 for(i = 0; i <= rest[0]; i++)
 816                         crc = crc8((crc ^ rest[i]) << 8);
 817         return crc;
 818 }
 819
 820 static u8 i2c_smbus_pec(int count, u8 *first, u8 *rest)
 821 {
 822         return i2c_smbus_partial_pec(0, count, first, rest);
 823 }
 824
 825 /* Returns new "size" (transaction type)
 826    Note that we convert byte to byte_data and byte_data to word_data
 827    rather than invent new xxx_PEC transactions. */
 828 static int i2c_smbus_add_pec(u16 addr, u8 command, int size,
 829                              union i2c_smbus_data *data)
 830 {
 831         u8 buf[3];
 832
 833         buf[0] = addr << 1;
 834         buf[1] = command;
 835         switch(size) {
 836                 case I2C_SMBUS_BYTE:
 837                         data->byte = i2c_smbus_pec(2, buf, NULL);
 838                         size = I2C_SMBUS_BYTE_DATA;
 839                         break;
 840                 case I2C_SMBUS_BYTE_DATA:
 841                         buf[2] = data->byte;
 842                         data->word = buf[2] ||
 843                                     (i2c_smbus_pec(3, buf, NULL) << 8);
 844                         size = I2C_SMBUS_WORD_DATA;
 845                         break;
 846                 case I2C_SMBUS_WORD_DATA:
 847                         /* unsupported */
 848                         break;
 849                 case I2C_SMBUS_BLOCK_DATA:
 850                         data->block[data->block[0] + 1] =
 851                                      i2c_smbus_pec(2, buf, data->block);
 852                         size = I2C_SMBUS_BLOCK_DATA_PEC;
 853                         break;
 854         }
 855         return size;
 856 }
 857
 858 static int i2c_smbus_check_pec(u16 addr, u8 command, int size, u8 partial,
 859                                union i2c_smbus_data *data)
 860 {
 861         u8 buf[3], rpec, cpec;
 862
 863         buf[1] = command;
 864         switch(size) {
 865                 case I2C_SMBUS_BYTE_DATA:
 866                         buf[0] = (addr << 1) | 1;
 867                         cpec = i2c_smbus_pec(2, buf, NULL);
 868                         rpec = data->byte;
 869                         break;
 870                 case I2C_SMBUS_WORD_DATA:
 871                         buf[0] = (addr << 1) | 1;
 872                         buf[2] = data->word & 0xff;
 873                         cpec = i2c_smbus_pec(3, buf, NULL);
 874                         rpec = data->word >> 8;
 875                         break;
 876                 case I2C_SMBUS_WORD_DATA_PEC:
 877                         /* unsupported */
 878                         cpec = rpec = 0;
 879                         break;
 880                 case I2C_SMBUS_PROC_CALL_PEC:
 881                         /* unsupported */
 882                         cpec = rpec = 0;
 883                         break;
 884                 case I2C_SMBUS_BLOCK_DATA_PEC:
 885                         buf[0] = (addr << 1);
 886                         buf[2] = (addr << 1) | 1;
 887                         cpec = i2c_smbus_pec(3, buf, data->block);
 888                         rpec = data->block[data->block[0] + 1];
 889                         break;
 890                 case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
 891                         buf[0] = (addr << 1) | 1;
 892                         rpec = i2c_smbus_partial_pec(partial, 1,
 893                                                      buf, data->block);
 894                         cpec = data->block[data->block[0] + 1];
 895                         break;
 896                 default:
 897                         cpec = rpec = 0;
 898                         break;
 899         }
 900         if (rpec != cpec) {
 901                 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
 902                         rpec, cpec);
 903                 return -1;
 904         }
 905         return 0;
 906 }
 907
 908 s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value)
 909 {
 910         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 911                               value,0,I2C_SMBUS_QUICK,NULL);
 912 }
 913
 914 s32 i2c_smbus_read_byte(struct i2c_client *client)
 915 {
 916         union i2c_smbus_data data;
 917         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 918                            I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data))
 919                 return -1;
 920         else
 921                 return 0x0FF & data.byte;
 922 }
 923
 924 s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
 925 {
 926         union i2c_smbus_data data;      /* only for PEC */
 927         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 928                               I2C_SMBUS_WRITE,value, I2C_SMBUS_BYTE,&data);
 929 }
 930
 931 s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
 932 {
 933         union i2c_smbus_data data;
 934         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 935                            I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data))
 936                 return -1;
 937         else
 938                 return 0x0FF & data.byte;
 939 }
 940
 941 s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
 942 {
 943         union i2c_smbus_data data;
 944         data.byte = value;
 945         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 946                               I2C_SMBUS_WRITE,command,
 947                               I2C_SMBUS_BYTE_DATA,&data);
 948 }
 949
 950 s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
 951 {
 952         union i2c_smbus_data data;
 953         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 954                            I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data))
 955                 return -1;
 956         else
 957                 return 0x0FFFF & data.word;
 958 }
 959
 960 s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
 961 {
 962         union i2c_smbus_data data;
 963         data.word = value;
 964         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 965                               I2C_SMBUS_WRITE,command,
 966                               I2C_SMBUS_WORD_DATA,&data);
 967 }
 968
 969 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
 970                                u8 length, u8 *values)
 971 {
 972         union i2c_smbus_data data;
 973         int i;
 974         if (length > I2C_SMBUS_BLOCK_MAX)
 975                 length = I2C_SMBUS_BLOCK_MAX;
 976         for (i = 1; i <= length; i++)
 977                 data.block[i] = values[i-1];
 978         data.block[0] = length;
 979         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 980                               I2C_SMBUS_WRITE,command,
 981                               I2C_SMBUS_BLOCK_DATA,&data);
 982 }
 983
 984 /* Returns the number of read bytes */
 985 s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command, u8 *values)
 986 {
 987         union i2c_smbus_data data;
 988         int i;
 989         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 990                               I2C_SMBUS_READ,command,
 991                               I2C_SMBUS_I2C_BLOCK_DATA,&data))
 992                 return -1;
 993         else {
 994                 for (i = 1; i <= data.block[0]; i++)
 995                         values[i-1] = data.block[i];
 996                 return data.block[0];
 997         }
 998 }
 999
1000 /* Simulate a SMBus command using the i2c protocol
1001    No checking of parameters is done!  */
1002 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
1003                                    unsigned short flags,
1004                                    char read_write, u8 command, int size,
1005                                    union i2c_smbus_data * data)
1006 {
1007         /* So we need to generate a series of msgs. In the case of writing, we
1008           need to use only one message; when reading, we need two. We initialize
1009           most things with sane defaults, to keep the code below somewhat
1010           simpler. */
1011         unsigned char msgbuf0[34];
1012         unsigned char msgbuf1[34];
1013         int num = read_write == I2C_SMBUS_READ?2:1;
1014         struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1015                                   { addr, flags | I2C_M_RD, 0, msgbuf1 }
1016                                 };
1017         int i;
1018
1019         msgbuf0[0] = command;
1020         switch(size) {
1021         case I2C_SMBUS_QUICK:
1022                 msg[0].len = 0;
1023                 /* Special case: The read/write field is used as data */
1024                 msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0;
1025                 num = 1;
1026                 break;
1027         case I2C_SMBUS_BYTE:
1028                 if (read_write == I2C_SMBUS_READ) {
1029                         /* Special case: only a read! */
1030                         msg[0].flags = I2C_M_RD | flags;
1031                         num = 1;
1032                 }
1033                 break;
1034         case I2C_SMBUS_BYTE_DATA:
1035                 if (read_write == I2C_SMBUS_READ)
1036                         msg[1].len = 1;
1037                 else {
1038                         msg[0].len = 2;
1039                         msgbuf0[1] = data->byte;
1040                 }
1041                 break;
1042         case I2C_SMBUS_WORD_DATA:
1043                 if (read_write == I2C_SMBUS_READ)
1044                         msg[1].len = 2;
1045                 else {
1046                         msg[0].len=3;
1047                         msgbuf0[1] = data->word & 0xff;
1048                         msgbuf0[2] = (data->word >> 8) & 0xff;
1049                 }
1050                 break;
1051         case I2C_SMBUS_PROC_CALL:
1052                 num = 2; /* Special case */
1053                 read_write = I2C_SMBUS_READ;
1054                 msg[0].len = 3;
1055                 msg[1].len = 2;
1056                 msgbuf0[1] = data->word & 0xff;
1057                 msgbuf0[2] = (data->word >> 8) & 0xff;
1058                 break;
1059         case I2C_SMBUS_BLOCK_DATA:
1060         case I2C_SMBUS_BLOCK_DATA_PEC:
1061                 if (read_write == I2C_SMBUS_READ) {
1062                         dev_err(&adapter->dev, "Block read not supported "
1063                                "under I2C emulation!\n");
1064                         return -1;
1065                 } else {
1066                         msg[0].len = data->block[0] + 2;
1067                         if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
1068                                 dev_err(&adapter->dev, "smbus_access called with "
1069                                        "invalid block write size (%d)\n",
1070                                        data->block[0]);
1071                                 return -1;
1072                         }
1073                         if(size == I2C_SMBUS_BLOCK_DATA_PEC)
1074                                 (msg[0].len)++;
1075                         for (i = 1; i <= msg[0].len; i++)
1076                                 msgbuf0[i] = data->block[i-1];
1077                 }
1078                 break;
1079         case I2C_SMBUS_BLOCK_PROC_CALL:
1080         case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
1081                 dev_dbg(&adapter->dev, "Block process call not supported "
1082                        "under I2C emulation!\n");
1083                 return -1;
1084         case I2C_SMBUS_I2C_BLOCK_DATA:
1085                 if (read_write == I2C_SMBUS_READ) {
1086                         msg[1].len = I2C_SMBUS_I2C_BLOCK_MAX;
1087                 } else {
1088                         msg[0].len = data->block[0] + 1;
1089                         if (msg[0].len > I2C_SMBUS_I2C_BLOCK_MAX + 1) {
1090                                 dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
1091                                        "invalid block write size (%d)\n",
1092                                        data->block[0]);
1093                                 return -1;
1094                         }
1095                         for (i = 1; i <= data->block[0]; i++)
1096                                 msgbuf0[i] = data->block[i];
1097                 }
1098                 break;
1099         default:
1100                 dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n",
1101                        size);
1102                 return -1;
1103         }
1104
1105         if (i2c_transfer(adapter, msg, num) < 0)
1106                 return -1;
1107
1108         if (read_write == I2C_SMBUS_READ)
1109                 switch(size) {
1110                         case I2C_SMBUS_BYTE:
1111                                 data->byte = msgbuf0[0];
1112                                 break;
1113                         case I2C_SMBUS_BYTE_DATA:
1114                                 data->byte = msgbuf1[0];
1115                                 break;
1116                         case I2C_SMBUS_WORD_DATA:
1117                         case I2C_SMBUS_PROC_CALL:
1118                                 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
1119                                 break;
1120                         case I2C_SMBUS_I2C_BLOCK_DATA:
1121                                 /* fixed at 32 for now */
1122                                 data->block[0] = I2C_SMBUS_I2C_BLOCK_MAX;
1123                                 for (i = 0; i < I2C_SMBUS_I2C_BLOCK_MAX; i++)
1124                                         data->block[i+1] = msgbuf1[i];
1125                                 break;
1126                 }
1127         return 0;
1128 }
1129
1130
1131 s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
1132                    char read_write, u8 command, int size,
1133                    union i2c_smbus_data * data)
1134 {
1135         s32 res;
1136         int swpec = 0;
1137         u8 partial = 0;
1138
1139         flags &= I2C_M_TEN | I2C_CLIENT_PEC;
1140         if((flags & I2C_CLIENT_PEC) &&
1141            !(i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HWPEC_CALC))) {
1142                 swpec = 1;
1143                 if(read_write == I2C_SMBUS_READ &&
1144                    size == I2C_SMBUS_BLOCK_DATA)
1145                         size = I2C_SMBUS_BLOCK_DATA_PEC;
1146                 else if(size == I2C_SMBUS_PROC_CALL)
1147                         size = I2C_SMBUS_PROC_CALL_PEC;
1148                 else if(size == I2C_SMBUS_BLOCK_PROC_CALL) {
1149                         i2c_smbus_add_pec(addr, command,
1150                                           I2C_SMBUS_BLOCK_DATA, data);
1151                         partial = data->block[data->block[0] + 1];
1152                         size = I2C_SMBUS_BLOCK_PROC_CALL_PEC;
1153                 } else if(read_write == I2C_SMBUS_WRITE &&
1154                           size != I2C_SMBUS_QUICK &&
1155                           size != I2C_SMBUS_I2C_BLOCK_DATA)
1156                         size = i2c_smbus_add_pec(addr, command, size, data);
1157         }
1158
1159         if (adapter->algo->smbus_xfer) {
1160                 down(&adapter->bus_lock);
1161                 res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
1162                                                 command,size,data);
1163                 up(&adapter->bus_lock);
1164         } else
1165                 res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
1166                                               command,size,data);
1167
1168         if(res >= 0 && swpec &&
1169            size != I2C_SMBUS_QUICK && size != I2C_SMBUS_I2C_BLOCK_DATA &&
1170            (read_write == I2C_SMBUS_READ || size == I2C_SMBUS_PROC_CALL_PEC ||
1171             size == I2C_SMBUS_BLOCK_PROC_CALL_PEC)) {
1172                 if(i2c_smbus_check_pec(addr, command, size, partial, data))
1173                         return -1;
1174         }
1175         return res;
1176 }
1177
1178
1179 EXPORT_SYMBOL(i2c_add_adapter);
1180 EXPORT_SYMBOL(i2c_del_adapter);
1181 EXPORT_SYMBOL(i2c_add_driver);
1182 EXPORT_SYMBOL(i2c_del_driver);
1183 EXPORT_SYMBOL(i2c_attach_client);
1184 EXPORT_SYMBOL(i2c_detach_client);
1185 EXPORT_SYMBOL(i2c_use_client);
1186 EXPORT_SYMBOL(i2c_release_client);
1187 EXPORT_SYMBOL(i2c_clients_command);
1188 EXPORT_SYMBOL(i2c_check_addr);
1189
1190 EXPORT_SYMBOL(i2c_master_send);
1191 EXPORT_SYMBOL(i2c_master_recv);
1192 EXPORT_SYMBOL(i2c_control);
1193 EXPORT_SYMBOL(i2c_transfer);
1194 EXPORT_SYMBOL(i2c_adapter_id);
1195 EXPORT_SYMBOL(i2c_get_adapter);
1196 EXPORT_SYMBOL(i2c_put_adapter);
1197 EXPORT_SYMBOL(i2c_probe);
1198
1199 EXPORT_SYMBOL(i2c_smbus_xfer);
1200 EXPORT_SYMBOL(i2c_smbus_write_quick);
1201 EXPORT_SYMBOL(i2c_smbus_read_byte);
1202 EXPORT_SYMBOL(i2c_smbus_write_byte);
1203 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1204 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1205 EXPORT_SYMBOL(i2c_smbus_read_word_data);
1206 EXPORT_SYMBOL(i2c_smbus_write_word_data);
1207 EXPORT_SYMBOL(i2c_smbus_write_block_data);
1208 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1209
1210 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1211 MODULE_DESCRIPTION("I2C-Bus main module");
1212 MODULE_LICENSE("GPL");