drivers/i2c/i2c-core.c

   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 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 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 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 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, adap, &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         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
 192
 193         /* inform drivers of new adapters */
 194         list_for_each(item,&drivers) {
 195                 driver = list_entry(item, struct i2c_driver, list);
 196                 if (driver->flags & I2C_DF_NOTIFY)
 197                         /* We ignore the return code; if it fails, too bad */
 198                         driver->attach_adapter(adap);
 199         }
 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-core: attempting to delete unregistered "
 224                          "adapter [%s]\n", adap->name);
 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_err(&adap->dev, "detach_adapter failed "
 234                                         "for driver [%s]\n", driver->name);
 235                                 goto out_unlock;
 236                         }
 237         }
 238
 239         /* detach any active clients. This must be done first, because
 240          * it can fail; in which case we give up. */
 241         list_for_each_safe(item, _n, &adap->clients) {
 242                 client = list_entry(item, struct i2c_client, list);
 243
 244                 /* detaching devices is unconditional of the set notify
 245                  * flag, as _all_ clients that reside on the adapter
 246                  * must be deleted, as this would cause invalid states.
 247                  */
 248                 if ((res=client->driver->detach_client(client))) {
 249                         dev_err(&adap->dev, "detach_client failed for client "
 250                                 "[%s] at address 0x%02x\n", client->name,
 251                                 client->addr);
 252                         goto out_unlock;
 253                 }
 254         }
 255
 256         /* clean up the sysfs representation */
 257         init_completion(&adap->dev_released);
 258         init_completion(&adap->class_dev_released);
 259         class_device_unregister(&adap->class_dev);
 260         device_remove_file(&adap->dev, &dev_attr_name);
 261         device_unregister(&adap->dev);
 262         list_del(&adap->list);
 263
 264         /* wait for sysfs to drop all references */
 265         wait_for_completion(&adap->dev_released);
 266         wait_for_completion(&adap->class_dev_released);
 267
 268         /* free dynamically allocated bus id */
 269         idr_remove(&i2c_adapter_idr, adap->nr);
 270
 271         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
 272
 273  out_unlock:
 274         up(&core_lists);
 275         return res;
 276 }
 277
 278
 279 /* -----
 280  * What follows is the "upwards" interface: commands for talking to clients,
 281  * which implement the functions to access the physical information of the
 282  * chips.
 283  */
 284
 285 int i2c_add_driver(struct i2c_driver *driver)
 286 {
 287         struct list_head   *item;
 288         struct i2c_adapter *adapter;
 289         int res = 0;
 290
 291         down(&core_lists);
 292
 293         /* add the driver to the list of i2c drivers in the driver core */
 294         driver->driver.name = driver->name;
 295         driver->driver.bus = &i2c_bus_type;
 296         driver->driver.probe = i2c_device_probe;
 297         driver->driver.remove = i2c_device_remove;
 298
 299         res = driver_register(&driver->driver);
 300         if (res)
 301                 goto out_unlock;
 302
 303         list_add_tail(&driver->list,&drivers);
 304         pr_debug("i2c-core: driver [%s] registered\n", driver->name);
 305
 306         /* now look for instances of driver on our adapters */
 307         if (driver->flags & I2C_DF_NOTIFY) {
 308                 list_for_each(item,&adapters) {
 309                         adapter = list_entry(item, struct i2c_adapter, list);
 310                         driver->attach_adapter(adapter);
 311                 }
 312         }
 313
 314  out_unlock:
 315         up(&core_lists);
 316         return res;
 317 }
 318
 319 int i2c_del_driver(struct i2c_driver *driver)
 320 {
 321         struct list_head   *item1, *item2, *_n;
 322         struct i2c_client  *client;
 323         struct i2c_adapter *adap;
 324
 325         int res = 0;
 326
 327         down(&core_lists);
 328
 329         /* Have a look at each adapter, if clients of this driver are still
 330          * attached. If so, detach them to be able to kill the driver
 331          * afterwards.
 332          *
 333          * Removing clients does not depend on the notify flag, else
 334          * invalid operation might (will!) result, when using stale client
 335          * pointers.
 336          */
 337         list_for_each(item1,&adapters) {
 338                 adap = list_entry(item1, struct i2c_adapter, list);
 339                 if (driver->detach_adapter) {
 340                         if ((res = driver->detach_adapter(adap))) {
 341                                 dev_err(&adap->dev, "detach_adapter failed "
 342                                         "for driver [%s]\n", driver->name);
 343                                 goto out_unlock;
 344                         }
 345                 } else {
 346                         list_for_each_safe(item2, _n, &adap->clients) {
 347                                 client = list_entry(item2, struct i2c_client, list);
 348                                 if (client->driver != driver)
 349                                         continue;
 350                                 dev_dbg(&adap->dev, "detaching client [%s] "
 351                                         "at 0x%02x\n", client->name,
 352                                         client->addr);
 353                                 if ((res = driver->detach_client(client))) {
 354                                         dev_err(&adap->dev, "detach_client "
 355                                                 "failed for client [%s] at "
 356                                                 "0x%02x\n", client->name,
 357                                                 client->addr);
 358                                         goto out_unlock;
 359                                 }
 360                         }
 361                 }
 362         }
 363
 364         driver_unregister(&driver->driver);
 365         list_del(&driver->list);
 366         pr_debug("i2c-core: driver [%s] unregistered\n", driver->name);
 367
 368  out_unlock:
 369         up(&core_lists);
 370         return 0;
 371 }
 372
 373 static int __i2c_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 374 {
 375         struct list_head   *item;
 376         struct i2c_client  *client;
 377
 378         list_for_each(item,&adapter->clients) {
 379                 client = list_entry(item, struct i2c_client, list);
 380                 if (client->addr == addr)
 381                         return -EBUSY;
 382         }
 383         return 0;
 384 }
 385
 386 int i2c_check_addr(struct i2c_adapter *adapter, int addr)
 387 {
 388         int rval;
 389
 390         down(&adapter->clist_lock);
 391         rval = __i2c_check_addr(adapter, addr);
 392         up(&adapter->clist_lock);
 393
 394         return rval;
 395 }
 396
 397 int i2c_attach_client(struct i2c_client *client)
 398 {
 399         struct i2c_adapter *adapter = client->adapter;
 400
 401         down(&adapter->clist_lock);
 402         if (__i2c_check_addr(client->adapter, client->addr)) {
 403                 up(&adapter->clist_lock);
 404                 return -EBUSY;
 405         }
 406         list_add_tail(&client->list,&adapter->clients);
 407         up(&adapter->clist_lock);
 408
 409         if (adapter->client_register)  {
 410                 if (adapter->client_register(client))  {
 411                         dev_dbg(&adapter->dev, "client_register "
 412                                 "failed for client [%s] at 0x%02x\n",
 413                                 client->name, client->addr);
 414                 }
 415         }
 416
 417         if (client->flags & I2C_CLIENT_ALLOW_USE)
 418                 client->usage_count = 0;
 419
 420         client->dev.parent = &client->adapter->dev;
 421         client->dev.driver = &client->driver->driver;
 422         client->dev.bus = &i2c_bus_type;
 423         client->dev.release = &i2c_client_release;
 424
 425         snprintf(&client->dev.bus_id[0], sizeof(client->dev.bus_id),
 426                 "%d-%04x", i2c_adapter_id(adapter), client->addr);
 427         dev_dbg(&adapter->dev, "client [%s] registered with bus id %s\n",
 428                 client->name, client->dev.bus_id);
 429         device_register(&client->dev);
 430         device_create_file(&client->dev, &dev_attr_client_name);
 431
 432         return 0;
 433 }
 434
 435
 436 int i2c_detach_client(struct i2c_client *client)
 437 {
 438         struct i2c_adapter *adapter = client->adapter;
 439         int res = 0;
 440
 441         if ((client->flags & I2C_CLIENT_ALLOW_USE)
 442          && (client->usage_count > 0)) {
 443                 dev_warn(&client->dev, "Client [%s] still busy, "
 444                          "can't detach\n", client->name);
 445                 return -EBUSY;
 446         }
 447
 448         if (adapter->client_unregister)  {
 449                 res = adapter->client_unregister(client);
 450                 if (res) {
 451                         dev_err(&client->dev,
 452                                 "client_unregister [%s] failed, "
 453                                 "client not detached\n", client->name);
 454                         goto out;
 455                 }
 456         }
 457
 458         down(&adapter->clist_lock);
 459         list_del(&client->list);
 460         init_completion(&client->released);
 461         device_remove_file(&client->dev, &dev_attr_client_name);
 462         device_unregister(&client->dev);
 463         up(&adapter->clist_lock);
 464         wait_for_completion(&client->released);
 465
 466  out:
 467         return res;
 468 }
 469
 470 static int i2c_inc_use_client(struct i2c_client *client)
 471 {
 472
 473         if (!try_module_get(client->driver->owner))
 474                 return -ENODEV;
 475         if (!try_module_get(client->adapter->owner)) {
 476                 module_put(client->driver->owner);
 477                 return -ENODEV;
 478         }
 479
 480         return 0;
 481 }
 482
 483 static void i2c_dec_use_client(struct i2c_client *client)
 484 {
 485         module_put(client->driver->owner);
 486         module_put(client->adapter->owner);
 487 }
 488
 489 int i2c_use_client(struct i2c_client *client)
 490 {
 491         int ret;
 492
 493         ret = i2c_inc_use_client(client);
 494         if (ret)
 495                 return ret;
 496
 497         if (client->flags & I2C_CLIENT_ALLOW_USE) {
 498                 if (client->flags & I2C_CLIENT_ALLOW_MULTIPLE_USE)
 499                         client->usage_count++;
 500                 else if (client->usage_count > 0)
 501                         goto busy;
 502                 else
 503                         client->usage_count++;
 504         }
 505
 506         return 0;
 507  busy:
 508         i2c_dec_use_client(client);
 509         return -EBUSY;
 510 }
 511
 512 int i2c_release_client(struct i2c_client *client)
 513 {
 514         if(client->flags & I2C_CLIENT_ALLOW_USE) {
 515                 if(client->usage_count>0)
 516                         client->usage_count--;
 517                 else {
 518                         pr_debug("i2c-core: %s used one too many times\n",
 519                                 __FUNCTION__);
 520                         return -EPERM;
 521                 }
 522         }
 523
 524         i2c_dec_use_client(client);
 525
 526         return 0;
 527 }
 528
 529 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
 530 {
 531         struct list_head  *item;
 532         struct i2c_client *client;
 533
 534         down(&adap->clist_lock);
 535         list_for_each(item,&adap->clients) {
 536                 client = list_entry(item, struct i2c_client, list);
 537                 if (!try_module_get(client->driver->owner))
 538                         continue;
 539                 if (NULL != client->driver->command) {
 540                         up(&adap->clist_lock);
 541                         client->driver->command(client,cmd,arg);
 542                         down(&adap->clist_lock);
 543                 }
 544                 module_put(client->driver->owner);
 545        }
 546        up(&adap->clist_lock);
 547 }
 548
 549 static int __init i2c_init(void)
 550 {
 551         int retval;
 552
 553         retval = bus_register(&i2c_bus_type);
 554         if (retval)
 555                 return retval;
 556         retval = driver_register(&i2c_adapter_driver);
 557         if (retval)
 558                 return retval;
 559         return class_register(&i2c_adapter_class);
 560 }
 561
 562 static void __exit i2c_exit(void)
 563 {
 564         class_unregister(&i2c_adapter_class);
 565         driver_unregister(&i2c_adapter_driver);
 566         bus_unregister(&i2c_bus_type);
 567 }
 568
 569 subsys_initcall(i2c_init);
 570 module_exit(i2c_exit);
 571
 572 /* ----------------------------------------------------
 573  * the functional interface to the i2c busses.
 574  * ----------------------------------------------------
 575  */
 576
 577 int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
 578 {
 579         int ret;
 580
 581         if (adap->algo->master_xfer) {
 582 #ifdef DEBUG
 583                 for (ret = 0; ret < num; ret++) {
 584                         dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
 585                                 "len=%d\n", ret, msgs[ret].flags & I2C_M_RD ?
 586                                 'R' : 'W', msgs[ret].addr, msgs[ret].len);
 587                 }
 588 #endif
 589
 590                 down(&adap->bus_lock);
 591                 ret = adap->algo->master_xfer(adap,msgs,num);
 592                 up(&adap->bus_lock);
 593
 594                 return ret;
 595         } else {
 596                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
 597                 return -ENOSYS;
 598         }
 599 }
 600
 601 int i2c_master_send(struct i2c_client *client,const char *buf ,int count)
 602 {
 603         int ret;
 604         struct i2c_adapter *adap=client->adapter;
 605         struct i2c_msg msg;
 606
 607         msg.addr = client->addr;
 608         msg.flags = client->flags & I2C_M_TEN;
 609         msg.len = count;
 610         msg.buf = (char *)buf;
 611
 612         ret = i2c_transfer(adap, &msg, 1);
 613
 614         /* If everything went ok (i.e. 1 msg transmitted), return #bytes
 615            transmitted, else error code. */
 616         return (ret == 1) ? count : ret;
 617 }
 618
 619 int i2c_master_recv(struct i2c_client *client, char *buf ,int count)
 620 {
 621         struct i2c_adapter *adap=client->adapter;
 622         struct i2c_msg msg;
 623         int ret;
 624
 625         msg.addr = client->addr;
 626         msg.flags = client->flags & I2C_M_TEN;
 627         msg.flags |= I2C_M_RD;
 628         msg.len = count;
 629         msg.buf = buf;
 630
 631         ret = i2c_transfer(adap, &msg, 1);
 632
 633         /* If everything went ok (i.e. 1 msg transmitted), return #bytes
 634            transmitted, else error code. */
 635         return (ret == 1) ? count : ret;
 636 }
 637
 638
 639 int i2c_control(struct i2c_client *client,
 640         unsigned int cmd, unsigned long arg)
 641 {
 642         int ret = 0;
 643         struct i2c_adapter *adap = client->adapter;
 644
 645         dev_dbg(&client->adapter->dev, "i2c ioctl, cmd: 0x%x, arg: %#lx\n", cmd, arg);
 646         switch (cmd) {
 647                 case I2C_RETRIES:
 648                         adap->retries = arg;
 649                         break;
 650                 case I2C_TIMEOUT:
 651                         adap->timeout = arg;
 652                         break;
 653                 default:
 654                         if (adap->algo->algo_control!=NULL)
 655                                 ret = adap->algo->algo_control(adap,cmd,arg);
 656         }
 657         return ret;
 658 }
 659
 660 /* ----------------------------------------------------
 661  * the i2c address scanning function
 662  * Will not work for 10-bit addresses!
 663  * ----------------------------------------------------
 664  */
 665 /* Return: kind (>= 0) if force found, -1 if not found */
 666 static inline int i2c_probe_forces(struct i2c_adapter *adapter, int addr,
 667                                    unsigned short **forces)
 668 {
 669         unsigned short kind;
 670         int j, adap_id = i2c_adapter_id(adapter);
 671
 672         for (kind = 0; forces[kind]; kind++) {
 673                 for (j = 0; forces[kind][j] != I2C_CLIENT_END; j += 2) {
 674                         if ((forces[kind][j] == adap_id ||
 675                              forces[kind][j] == ANY_I2C_BUS)
 676                          && forces[kind][j + 1] == addr) {
 677                                 dev_dbg(&adapter->dev, "found force parameter, "
 678                                         "addr 0x%02x, kind %u\n", addr, kind);
 679                                 return kind;
 680                         }
 681                 }
 682         }
 683
 684         return -1;
 685 }
 686
 687 int i2c_probe(struct i2c_adapter *adapter,
 688               struct i2c_client_address_data *address_data,
 689               int (*found_proc) (struct i2c_adapter *, int, int))
 690 {
 691         int addr,i,found,err;
 692         int adap_id = i2c_adapter_id(adapter);
 693
 694         /* Forget it if we can't probe using SMBUS_QUICK */
 695         if (! i2c_check_functionality(adapter,I2C_FUNC_SMBUS_QUICK))
 696                 return -1;
 697
 698         for (addr = 0x00; addr <= 0x7f; addr++) {
 699
 700                 /* Skip if already in use */
 701                 if (i2c_check_addr(adapter,addr))
 702                         continue;
 703
 704                 /* If it is in one of the force entries, we don't do any detection
 705                    at all */
 706                 found = 0;
 707
 708                 if (address_data->forces) {
 709                         int kind = i2c_probe_forces(adapter, addr,
 710                                                     address_data->forces);
 711                         if (kind >= 0) { /* force found */
 712                                 if ((err = found_proc(adapter, addr, kind)))
 713                                         return err;
 714                                 continue;
 715                         }
 716                 }
 717
 718                 /* If this address is in one of the ignores, we can forget about
 719                    it right now */
 720                 for (i = 0;
 721                      !found && (address_data->ignore[i] != I2C_CLIENT_END);
 722                      i += 2) {
 723                         if (((adap_id == address_data->ignore[i]) ||
 724                             ((address_data->ignore[i] == ANY_I2C_BUS))) &&
 725                             (addr == address_data->ignore[i+1])) {
 726                                 dev_dbg(&adapter->dev, "found ignore parameter for adapter %d, "
 727                                         "addr %04x\n", adap_id ,addr);
 728                                 found = 1;
 729                         }
 730                 }
 731                 if (found)
 732                         continue;
 733
 734                 /* Now, we will do a detection, but only if it is in the normal or
 735                    probe entries */
 736                 for (i = 0;
 737                      !found && (address_data->normal_i2c[i] != I2C_CLIENT_END);
 738                      i += 1) {
 739                         if (addr == address_data->normal_i2c[i]) {
 740                                 found = 1;
 741                                 dev_dbg(&adapter->dev, "found normal i2c entry for adapter %d, "
 742                                         "addr %02x\n", adap_id, addr);
 743                         }
 744                 }
 745
 746                 for (i = 0;
 747                      !found && (address_data->probe[i] != I2C_CLIENT_END);
 748                      i += 2) {
 749                         if (((adap_id == address_data->probe[i]) ||
 750                             ((address_data->probe[i] == ANY_I2C_BUS))) &&
 751                             (addr == address_data->probe[i+1])) {
 752                                 found = 1;
 753                                 dev_dbg(&adapter->dev, "found probe parameter for adapter %d, "
 754                                         "addr %04x\n", adap_id,addr);
 755                         }
 756                 }
 757                 if (!found)
 758                         continue;
 759
 760                 /* OK, so we really should examine this address. First check
 761                    whether there is some client here at all! */
 762                 if (i2c_smbus_xfer(adapter,addr,0,0,0,I2C_SMBUS_QUICK,NULL) >= 0)
 763                         if ((err = found_proc(adapter,addr,-1)))
 764                                 return err;
 765         }
 766         return 0;
 767 }
 768
 769 struct i2c_adapter* i2c_get_adapter(int id)
 770 {
 771         struct i2c_adapter *adapter;
 772
 773         down(&core_lists);
 774         adapter = (struct i2c_adapter *)idr_find(&i2c_adapter_idr, id);
 775         if (adapter && !try_module_get(adapter->owner))
 776                 adapter = NULL;
 777
 778         up(&core_lists);
 779         return adapter;
 780 }
 781
 782 void i2c_put_adapter(struct i2c_adapter *adap)
 783 {
 784         module_put(adap->owner);
 785 }
 786
 787 /* The SMBus parts */
 788
 789 #define POLY    (0x1070U << 3)
 790 static u8
 791 crc8(u16 data)
 792 {
 793         int i;
 794
 795         for(i = 0; i < 8; i++) {
 796                 if (data & 0x8000)
 797                         data = data ^ POLY;
 798                 data = data << 1;
 799         }
 800         return (u8)(data >> 8);
 801 }
 802
 803 /* CRC over count bytes in the first array plus the bytes in the rest
 804    array if it is non-null. rest[0] is the (length of rest) - 1
 805    and is included. */
 806 static u8 i2c_smbus_partial_pec(u8 crc, int count, u8 *first, u8 *rest)
 807 {
 808         int i;
 809
 810         for(i = 0; i < count; i++)
 811                 crc = crc8((crc ^ first[i]) << 8);
 812         if(rest != NULL)
 813                 for(i = 0; i <= rest[0]; i++)
 814                         crc = crc8((crc ^ rest[i]) << 8);
 815         return crc;
 816 }
 817
 818 static u8 i2c_smbus_pec(int count, u8 *first, u8 *rest)
 819 {
 820         return i2c_smbus_partial_pec(0, count, first, rest);
 821 }
 822
 823 /* Returns new "size" (transaction type)
 824    Note that we convert byte to byte_data and byte_data to word_data
 825    rather than invent new xxx_PEC transactions. */
 826 static int i2c_smbus_add_pec(u16 addr, u8 command, int size,
 827                              union i2c_smbus_data *data)
 828 {
 829         u8 buf[3];
 830
 831         buf[0] = addr << 1;
 832         buf[1] = command;
 833         switch(size) {
 834                 case I2C_SMBUS_BYTE:
 835                         data->byte = i2c_smbus_pec(2, buf, NULL);
 836                         size = I2C_SMBUS_BYTE_DATA;
 837                         break;
 838                 case I2C_SMBUS_BYTE_DATA:
 839                         buf[2] = data->byte;
 840                         data->word = buf[2] ||
 841                                     (i2c_smbus_pec(3, buf, NULL) << 8);
 842                         size = I2C_SMBUS_WORD_DATA;
 843                         break;
 844                 case I2C_SMBUS_WORD_DATA:
 845                         /* unsupported */
 846                         break;
 847                 case I2C_SMBUS_BLOCK_DATA:
 848                         data->block[data->block[0] + 1] =
 849                                      i2c_smbus_pec(2, buf, data->block);
 850                         size = I2C_SMBUS_BLOCK_DATA_PEC;
 851                         break;
 852         }
 853         return size;
 854 }
 855
 856 static int i2c_smbus_check_pec(u16 addr, u8 command, int size, u8 partial,
 857                                union i2c_smbus_data *data)
 858 {
 859         u8 buf[3], rpec, cpec;
 860
 861         buf[1] = command;
 862         switch(size) {
 863                 case I2C_SMBUS_BYTE_DATA:
 864                         buf[0] = (addr << 1) | 1;
 865                         cpec = i2c_smbus_pec(2, buf, NULL);
 866                         rpec = data->byte;
 867                         break;
 868                 case I2C_SMBUS_WORD_DATA:
 869                         buf[0] = (addr << 1) | 1;
 870                         buf[2] = data->word & 0xff;
 871                         cpec = i2c_smbus_pec(3, buf, NULL);
 872                         rpec = data->word >> 8;
 873                         break;
 874                 case I2C_SMBUS_WORD_DATA_PEC:
 875                         /* unsupported */
 876                         cpec = rpec = 0;
 877                         break;
 878                 case I2C_SMBUS_PROC_CALL_PEC:
 879                         /* unsupported */
 880                         cpec = rpec = 0;
 881                         break;
 882                 case I2C_SMBUS_BLOCK_DATA_PEC:
 883                         buf[0] = (addr << 1);
 884                         buf[2] = (addr << 1) | 1;
 885                         cpec = i2c_smbus_pec(3, buf, data->block);
 886                         rpec = data->block[data->block[0] + 1];
 887                         break;
 888                 case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
 889                         buf[0] = (addr << 1) | 1;
 890                         rpec = i2c_smbus_partial_pec(partial, 1,
 891                                                      buf, data->block);
 892                         cpec = data->block[data->block[0] + 1];
 893                         break;
 894                 default:
 895                         cpec = rpec = 0;
 896                         break;
 897         }
 898         if (rpec != cpec) {
 899                 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
 900                         rpec, cpec);
 901                 return -1;
 902         }
 903         return 0;
 904 }
 905
 906 s32 i2c_smbus_write_quick(struct i2c_client *client, u8 value)
 907 {
 908         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 909                               value,0,I2C_SMBUS_QUICK,NULL);
 910 }
 911
 912 s32 i2c_smbus_read_byte(struct i2c_client *client)
 913 {
 914         union i2c_smbus_data data;
 915         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 916                            I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data))
 917                 return -1;
 918         else
 919                 return 0x0FF & data.byte;
 920 }
 921
 922 s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
 923 {
 924         union i2c_smbus_data data;      /* only for PEC */
 925         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 926                               I2C_SMBUS_WRITE,value, I2C_SMBUS_BYTE,&data);
 927 }
 928
 929 s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
 930 {
 931         union i2c_smbus_data data;
 932         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 933                            I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data))
 934                 return -1;
 935         else
 936                 return 0x0FF & data.byte;
 937 }
 938
 939 s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
 940 {
 941         union i2c_smbus_data data;
 942         data.byte = value;
 943         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 944                               I2C_SMBUS_WRITE,command,
 945                               I2C_SMBUS_BYTE_DATA,&data);
 946 }
 947
 948 s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
 949 {
 950         union i2c_smbus_data data;
 951         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 952                            I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data))
 953                 return -1;
 954         else
 955                 return 0x0FFFF & data.word;
 956 }
 957
 958 s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
 959 {
 960         union i2c_smbus_data data;
 961         data.word = value;
 962         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 963                               I2C_SMBUS_WRITE,command,
 964                               I2C_SMBUS_WORD_DATA,&data);
 965 }
 966
 967 s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
 968                                u8 length, u8 *values)
 969 {
 970         union i2c_smbus_data data;
 971         int i;
 972         if (length > I2C_SMBUS_BLOCK_MAX)
 973                 length = I2C_SMBUS_BLOCK_MAX;
 974         for (i = 1; i <= length; i++)
 975                 data.block[i] = values[i-1];
 976         data.block[0] = length;
 977         return i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 978                               I2C_SMBUS_WRITE,command,
 979                               I2C_SMBUS_BLOCK_DATA,&data);
 980 }
 981
 982 /* Returns the number of read bytes */
 983 s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command, u8 *values)
 984 {
 985         union i2c_smbus_data data;
 986         int i;
 987         if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
 988                               I2C_SMBUS_READ,command,
 989                               I2C_SMBUS_I2C_BLOCK_DATA,&data))
 990                 return -1;
 991         else {
 992                 for (i = 1; i <= data.block[0]; i++)
 993                         values[i-1] = data.block[i];
 994                 return data.block[0];
 995         }
 996 }
 997
 998 /* Simulate a SMBus command using the i2c protocol
 999    No checking of parameters is done!  */
1000 static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
1001                                    unsigned short flags,
1002                                    char read_write, u8 command, int size,
1003                                    union i2c_smbus_data * data)
1004 {
1005         /* So we need to generate a series of msgs. In the case of writing, we
1006           need to use only one message; when reading, we need two. We initialize
1007           most things with sane defaults, to keep the code below somewhat
1008           simpler. */
1009         unsigned char msgbuf0[34];
1010         unsigned char msgbuf1[34];
1011         int num = read_write == I2C_SMBUS_READ?2:1;
1012         struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 },
1013                                   { addr, flags | I2C_M_RD, 0, msgbuf1 }
1014                                 };
1015         int i;
1016
1017         msgbuf0[0] = command;
1018         switch(size) {
1019         case I2C_SMBUS_QUICK:
1020                 msg[0].len = 0;
1021                 /* Special case: The read/write field is used as data */
1022                 msg[0].flags = flags | (read_write==I2C_SMBUS_READ)?I2C_M_RD:0;
1023                 num = 1;
1024                 break;
1025         case I2C_SMBUS_BYTE:
1026                 if (read_write == I2C_SMBUS_READ) {
1027                         /* Special case: only a read! */
1028                         msg[0].flags = I2C_M_RD | flags;
1029                         num = 1;
1030                 }
1031                 break;
1032         case I2C_SMBUS_BYTE_DATA:
1033                 if (read_write == I2C_SMBUS_READ)
1034                         msg[1].len = 1;
1035                 else {
1036                         msg[0].len = 2;
1037                         msgbuf0[1] = data->byte;
1038                 }
1039                 break;
1040         case I2C_SMBUS_WORD_DATA:
1041                 if (read_write == I2C_SMBUS_READ)
1042                         msg[1].len = 2;
1043                 else {
1044                         msg[0].len=3;
1045                         msgbuf0[1] = data->word & 0xff;
1046                         msgbuf0[2] = (data->word >> 8) & 0xff;
1047                 }
1048                 break;
1049         case I2C_SMBUS_PROC_CALL:
1050                 num = 2; /* Special case */
1051                 read_write = I2C_SMBUS_READ;
1052                 msg[0].len = 3;
1053                 msg[1].len = 2;
1054                 msgbuf0[1] = data->word & 0xff;
1055                 msgbuf0[2] = (data->word >> 8) & 0xff;
1056                 break;
1057         case I2C_SMBUS_BLOCK_DATA:
1058         case I2C_SMBUS_BLOCK_DATA_PEC:
1059                 if (read_write == I2C_SMBUS_READ) {
1060                         dev_err(&adapter->dev, "Block read not supported "
1061                                "under I2C emulation!\n");
1062                         return -1;
1063                 } else {
1064                         msg[0].len = data->block[0] + 2;
1065                         if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
1066                                 dev_err(&adapter->dev, "smbus_access called with "
1067                                        "invalid block write size (%d)\n",
1068                                        data->block[0]);
1069                                 return -1;
1070                         }
1071                         if(size == I2C_SMBUS_BLOCK_DATA_PEC)
1072                                 (msg[0].len)++;
1073                         for (i = 1; i <= msg[0].len; i++)
1074                                 msgbuf0[i] = data->block[i-1];
1075                 }
1076                 break;
1077         case I2C_SMBUS_BLOCK_PROC_CALL:
1078         case I2C_SMBUS_BLOCK_PROC_CALL_PEC:
1079                 dev_dbg(&adapter->dev, "Block process call not supported "
1080                        "under I2C emulation!\n");
1081                 return -1;
1082         case I2C_SMBUS_I2C_BLOCK_DATA:
1083                 if (read_write == I2C_SMBUS_READ) {
1084                         msg[1].len = I2C_SMBUS_I2C_BLOCK_MAX;
1085                 } else {
1086                         msg[0].len = data->block[0] + 1;
1087                         if (msg[0].len > I2C_SMBUS_I2C_BLOCK_MAX + 1) {
1088                                 dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
1089                                        "invalid block write size (%d)\n",
1090                                        data->block[0]);
1091                                 return -1;
1092                         }
1093                         for (i = 1; i <= data->block[0]; i++)
1094                                 msgbuf0[i] = data->block[i];
1095                 }
1096                 break;
1097         default:
1098                 dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n",
1099                        size);
1100                 return -1;
1101         }
1102
1103         if (i2c_transfer(adapter, msg, num) < 0)
1104                 return -1;
1105
1106         if (read_write == I2C_SMBUS_READ)
1107                 switch(size) {
1108                         case I2C_SMBUS_BYTE:
1109                                 data->byte = msgbuf0[0];
1110                                 break;
1111                         case I2C_SMBUS_BYTE_DATA:
1112                                 data->byte = msgbuf1[0];
1113                                 break;
1114                         case I2C_SMBUS_WORD_DATA:
1115                         case I2C_SMBUS_PROC_CALL:
1116                                 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
1117                                 break;
1118                         case I2C_SMBUS_I2C_BLOCK_DATA:
1119                                 /* fixed at 32 for now */
1120                                 data->block[0] = I2C_SMBUS_I2C_BLOCK_MAX;
1121                                 for (i = 0; i < I2C_SMBUS_I2C_BLOCK_MAX; i++)
1122                                         data->block[i+1] = msgbuf1[i];
1123                                 break;
1124                 }
1125         return 0;
1126 }
1127
1128
1129 s32 i2c_smbus_xfer(struct i2c_adapter * adapter, u16 addr, unsigned short flags,
1130                    char read_write, u8 command, int size,
1131                    union i2c_smbus_data * data)
1132 {
1133         s32 res;
1134         int swpec = 0;
1135         u8 partial = 0;
1136
1137         flags &= I2C_M_TEN | I2C_CLIENT_PEC;
1138         if((flags & I2C_CLIENT_PEC) &&
1139            !(i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HWPEC_CALC))) {
1140                 swpec = 1;
1141                 if(read_write == I2C_SMBUS_READ &&
1142                    size == I2C_SMBUS_BLOCK_DATA)
1143                         size = I2C_SMBUS_BLOCK_DATA_PEC;
1144                 else if(size == I2C_SMBUS_PROC_CALL)
1145                         size = I2C_SMBUS_PROC_CALL_PEC;
1146                 else if(size == I2C_SMBUS_BLOCK_PROC_CALL) {
1147                         i2c_smbus_add_pec(addr, command,
1148                                           I2C_SMBUS_BLOCK_DATA, data);
1149                         partial = data->block[data->block[0] + 1];
1150                         size = I2C_SMBUS_BLOCK_PROC_CALL_PEC;
1151                 } else if(read_write == I2C_SMBUS_WRITE &&
1152                           size != I2C_SMBUS_QUICK &&
1153                           size != I2C_SMBUS_I2C_BLOCK_DATA)
1154                         size = i2c_smbus_add_pec(addr, command, size, data);
1155         }
1156
1157         if (adapter->algo->smbus_xfer) {
1158                 down(&adapter->bus_lock);
1159                 res = adapter->algo->smbus_xfer(adapter,addr,flags,read_write,
1160                                                 command,size,data);
1161                 up(&adapter->bus_lock);
1162         } else
1163                 res = i2c_smbus_xfer_emulated(adapter,addr,flags,read_write,
1164                                               command,size,data);
1165
1166         if(res >= 0 && swpec &&
1167            size != I2C_SMBUS_QUICK && size != I2C_SMBUS_I2C_BLOCK_DATA &&
1168            (read_write == I2C_SMBUS_READ || size == I2C_SMBUS_PROC_CALL_PEC ||
1169             size == I2C_SMBUS_BLOCK_PROC_CALL_PEC)) {
1170                 if(i2c_smbus_check_pec(addr, command, size, partial, data))
1171                         return -1;
1172         }
1173         return res;
1174 }
1175
1176
1177 /* Next four are needed by i2c-isa */
1178 EXPORT_SYMBOL_GPL(i2c_adapter_dev_release);
1179 EXPORT_SYMBOL_GPL(i2c_adapter_driver);
1180 EXPORT_SYMBOL_GPL(i2c_adapter_class);
1181 EXPORT_SYMBOL_GPL(i2c_bus_type);
1182
1183 EXPORT_SYMBOL(i2c_add_adapter);
1184 EXPORT_SYMBOL(i2c_del_adapter);
1185 EXPORT_SYMBOL(i2c_add_driver);
1186 EXPORT_SYMBOL(i2c_del_driver);
1187 EXPORT_SYMBOL(i2c_attach_client);
1188 EXPORT_SYMBOL(i2c_detach_client);
1189 EXPORT_SYMBOL(i2c_use_client);
1190 EXPORT_SYMBOL(i2c_release_client);
1191 EXPORT_SYMBOL(i2c_clients_command);
1192 EXPORT_SYMBOL(i2c_check_addr);
1193
1194 EXPORT_SYMBOL(i2c_master_send);
1195 EXPORT_SYMBOL(i2c_master_recv);
1196 EXPORT_SYMBOL(i2c_control);
1197 EXPORT_SYMBOL(i2c_transfer);
1198 EXPORT_SYMBOL(i2c_get_adapter);
1199 EXPORT_SYMBOL(i2c_put_adapter);
1200 EXPORT_SYMBOL(i2c_probe);
1201
1202 EXPORT_SYMBOL(i2c_smbus_xfer);
1203 EXPORT_SYMBOL(i2c_smbus_write_quick);
1204 EXPORT_SYMBOL(i2c_smbus_read_byte);
1205 EXPORT_SYMBOL(i2c_smbus_write_byte);
1206 EXPORT_SYMBOL(i2c_smbus_read_byte_data);
1207 EXPORT_SYMBOL(i2c_smbus_write_byte_data);
1208 EXPORT_SYMBOL(i2c_smbus_read_word_data);
1209 EXPORT_SYMBOL(i2c_smbus_write_word_data);
1210 EXPORT_SYMBOL(i2c_smbus_write_block_data);
1211 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
1212
1213 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
1214 MODULE_DESCRIPTION("I2C-Bus main module");
1215 MODULE_LICENSE("GPL");