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> and 23 Jean Delvare <khali@linux-fr.org> 24 Mux support by Rodolfo Giometti <giometti@enneenne.com> and 25 Michael Lawnick <michael.lawnick.ext@nsn.com> */ 26 27#include <linux/module.h> 28#include <linux/kernel.h> 29#include <linux/errno.h> 30#include <linux/slab.h> 31#include <linux/i2c.h> 32#include <linux/init.h> 33#include <linux/idr.h> 34#include <linux/mutex.h> 35#include <linux/of_device.h> 36#include <linux/completion.h> 37#include <linux/hardirq.h> 38#include <linux/irqflags.h> 39#include <linux/rwsem.h> 40#include <linux/pm_runtime.h> 41#include <asm/uaccess.h> 42 43#include "i2c-core.h" 44 45 46/* core_lock protects i2c_adapter_idr, and guarantees 47 that device detection, deletion of detected devices, and attach_adapter 48 and detach_adapter calls are serialized */ 49static DEFINE_MUTEX(core_lock); 50static DEFINE_IDR(i2c_adapter_idr); 51 52static struct device_type i2c_client_type; 53static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver); 54 55/* ------------------------------------------------------------------------- */ 56 57static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id, 58 const struct i2c_client *client) 59{ 60 while (id->name[0]) { 61 if (strcmp(client->name, id->name) == 0) 62 return id; 63 id++; 64 } 65 return NULL; 66} 67 68static int i2c_device_match(struct device *dev, struct device_driver *drv) 69{ 70 struct i2c_client *client = i2c_verify_client(dev); 71 struct i2c_driver *driver; 72 73 if (!client) 74 return 0; 75 76 /* Attempt an OF style match */ 77 if (of_driver_match_device(dev, drv)) 78 return 1; 79 80 driver = to_i2c_driver(drv); 81 /* match on an id table if there is one */ 82 if (driver->id_table) 83 return i2c_match_id(driver->id_table, client) != NULL; 84 85 return 0; 86} 87 88#ifdef CONFIG_HOTPLUG 89 90/* uevent helps with hotplug: modprobe -q $(MODALIAS) */ 91static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env) 92{ 93 struct i2c_client *client = to_i2c_client(dev); 94 95 if (add_uevent_var(env, "MODALIAS=%s%s", 96 I2C_MODULE_PREFIX, client->name)) 97 return -ENOMEM; 98 dev_dbg(dev, "uevent\n"); 99 return 0; 100} 101 102#else 103#define i2c_device_uevent NULL 104#endif /* CONFIG_HOTPLUG */ 105 106static int i2c_device_probe(struct device *dev) 107{ 108 struct i2c_client *client = i2c_verify_client(dev); 109 struct i2c_driver *driver; 110 int status; 111 112 if (!client) 113 return 0; 114 115 driver = to_i2c_driver(dev->driver); 116 if (!driver->probe || !driver->id_table) 117 return -ENODEV; 118 client->driver = driver; 119 if (!device_can_wakeup(&client->dev)) 120 device_init_wakeup(&client->dev, 121 client->flags & I2C_CLIENT_WAKE); 122 dev_dbg(dev, "probe\n"); 123 124 status = driver->probe(client, i2c_match_id(driver->id_table, client)); 125 if (status) { 126 client->driver = NULL; 127 i2c_set_clientdata(client, NULL); 128 } 129 return status; 130} 131 132static int i2c_device_remove(struct device *dev) 133{ 134 struct i2c_client *client = i2c_verify_client(dev); 135 struct i2c_driver *driver; 136 int status; 137 138 if (!client || !dev->driver) 139 return 0; 140 141 driver = to_i2c_driver(dev->driver); 142 if (driver->remove) { 143 dev_dbg(dev, "remove\n"); 144 status = driver->remove(client); 145 } else { 146 dev->driver = NULL; 147 status = 0; 148 } 149 if (status == 0) { 150 client->driver = NULL; 151 i2c_set_clientdata(client, NULL); 152 } 153 return status; 154} 155 156static void i2c_device_shutdown(struct device *dev) 157{ 158 struct i2c_client *client = i2c_verify_client(dev); 159 struct i2c_driver *driver; 160 161 if (!client || !dev->driver) 162 return; 163 driver = to_i2c_driver(dev->driver); 164 if (driver->shutdown) 165 driver->shutdown(client); 166} 167 168#ifdef CONFIG_PM_SLEEP 169static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg) 170{ 171 struct i2c_client *client = i2c_verify_client(dev); 172 struct i2c_driver *driver; 173 174 if (!client || !dev->driver) 175 return 0; 176 driver = to_i2c_driver(dev->driver); 177 if (!driver->suspend) 178 return 0; 179 return driver->suspend(client, mesg); 180} 181 182static int i2c_legacy_resume(struct device *dev) 183{ 184 struct i2c_client *client = i2c_verify_client(dev); 185 struct i2c_driver *driver; 186 187 if (!client || !dev->driver) 188 return 0; 189 driver = to_i2c_driver(dev->driver); 190 if (!driver->resume) 191 return 0; 192 return driver->resume(client); 193} 194 195static int i2c_device_pm_suspend(struct device *dev) 196{ 197 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; 198 199 if (pm) 200 return pm_generic_suspend(dev); 201 else 202 return i2c_legacy_suspend(dev, PMSG_SUSPEND); 203} 204 205static int i2c_device_pm_resume(struct device *dev) 206{ 207 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; 208 209 if (pm) 210 return pm_generic_resume(dev); 211 else 212 return i2c_legacy_resume(dev); 213} 214 215static int i2c_device_pm_freeze(struct device *dev) 216{ 217 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; 218 219 if (pm) 220 return pm_generic_freeze(dev); 221 else 222 return i2c_legacy_suspend(dev, PMSG_FREEZE); 223} 224 225static int i2c_device_pm_thaw(struct device *dev) 226{ 227 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; 228 229 if (pm) 230 return pm_generic_thaw(dev); 231 else 232 return i2c_legacy_resume(dev); 233} 234 235static int i2c_device_pm_poweroff(struct device *dev) 236{ 237 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; 238 239 if (pm) 240 return pm_generic_poweroff(dev); 241 else 242 return i2c_legacy_suspend(dev, PMSG_HIBERNATE); 243} 244 245static int i2c_device_pm_restore(struct device *dev) 246{ 247 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; 248 249 if (pm) 250 return pm_generic_restore(dev); 251 else 252 return i2c_legacy_resume(dev); 253} 254#else /* !CONFIG_PM_SLEEP */ 255#define i2c_device_pm_suspend NULL 256#define i2c_device_pm_resume NULL 257#define i2c_device_pm_freeze NULL 258#define i2c_device_pm_thaw NULL 259#define i2c_device_pm_poweroff NULL 260#define i2c_device_pm_restore NULL 261#endif /* !CONFIG_PM_SLEEP */ 262 263static void i2c_client_dev_release(struct device *dev) 264{ 265 kfree(to_i2c_client(dev)); 266} 267 268static ssize_t 269show_name(struct device *dev, struct device_attribute *attr, char *buf) 270{ 271 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ? 272 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name); 273} 274 275static ssize_t 276show_modalias(struct device *dev, struct device_attribute *attr, char *buf) 277{ 278 struct i2c_client *client = to_i2c_client(dev); 279 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name); 280} 281 282static DEVICE_ATTR(name, S_IRUGO, show_name, NULL); 283static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL); 284 285static struct attribute *i2c_dev_attrs[] = { 286 &dev_attr_name.attr, 287 /* modalias helps coldplug: modprobe $(cat .../modalias) */ 288 &dev_attr_modalias.attr, 289 NULL 290}; 291 292static struct attribute_group i2c_dev_attr_group = { 293 .attrs = i2c_dev_attrs, 294}; 295 296static const struct attribute_group *i2c_dev_attr_groups[] = { 297 &i2c_dev_attr_group, 298 NULL 299}; 300 301static const struct dev_pm_ops i2c_device_pm_ops = { 302 .suspend = i2c_device_pm_suspend, 303 .resume = i2c_device_pm_resume, 304 .freeze = i2c_device_pm_freeze, 305 .thaw = i2c_device_pm_thaw, 306 .poweroff = i2c_device_pm_poweroff, 307 .restore = i2c_device_pm_restore, 308 SET_RUNTIME_PM_OPS( 309 pm_generic_runtime_suspend, 310 pm_generic_runtime_resume, 311 pm_generic_runtime_idle 312 ) 313}; 314 315struct bus_type i2c_bus_type = { 316 .name = "i2c", 317 .match = i2c_device_match, 318 .probe = i2c_device_probe, 319 .remove = i2c_device_remove, 320 .shutdown = i2c_device_shutdown, 321 .pm = &i2c_device_pm_ops, 322}; 323EXPORT_SYMBOL_GPL(i2c_bus_type); 324 325static struct device_type i2c_client_type = { 326 .groups = i2c_dev_attr_groups, 327 .uevent = i2c_device_uevent, 328 .release = i2c_client_dev_release, 329}; 330 331 332/** 333 * i2c_verify_client - return parameter as i2c_client, or NULL 334 * @dev: device, probably from some driver model iterator 335 * 336 * When traversing the driver model tree, perhaps using driver model 337 * iterators like @device_for_each_child(), you can't assume very much 338 * about the nodes you find. Use this function to avoid oopses caused 339 * by wrongly treating some non-I2C device as an i2c_client. 340 */ 341struct i2c_client *i2c_verify_client(struct device *dev) 342{ 343 return (dev->type == &i2c_client_type) 344 ? to_i2c_client(dev) 345 : NULL; 346} 347EXPORT_SYMBOL(i2c_verify_client); 348 349 350/* This is a permissive address validity check, I2C address map constraints 351 * are purposely not enforced, except for the general call address. */ 352static int i2c_check_client_addr_validity(const struct i2c_client *client) 353{ 354 if (client->flags & I2C_CLIENT_TEN) { 355 /* 10-bit address, all values are valid */ 356 if (client->addr > 0x3ff) 357 return -EINVAL; 358 } else { 359 /* 7-bit address, reject the general call address */ 360 if (client->addr == 0x00 || client->addr > 0x7f) 361 return -EINVAL; 362 } 363 return 0; 364} 365 366/* And this is a strict address validity check, used when probing. If a 367 * device uses a reserved address, then it shouldn't be probed. 7-bit 368 * addressing is assumed, 10-bit address devices are rare and should be 369 * explicitly enumerated. */ 370static int i2c_check_addr_validity(unsigned short addr) 371{ 372 /* 373 * Reserved addresses per I2C specification: 374 * 0x00 General call address / START byte 375 * 0x01 CBUS address 376 * 0x02 Reserved for different bus format 377 * 0x03 Reserved for future purposes 378 * 0x04-0x07 Hs-mode master code 379 * 0x78-0x7b 10-bit slave addressing 380 * 0x7c-0x7f Reserved for future purposes 381 */ 382 if (addr < 0x08 || addr > 0x77) 383 return -EINVAL; 384 return 0; 385} 386 387static int __i2c_check_addr_busy(struct device *dev, void *addrp) 388{ 389 struct i2c_client *client = i2c_verify_client(dev); 390 int addr = *(int *)addrp; 391 392 if (client && client->addr == addr) 393 return -EBUSY; 394 return 0; 395} 396 397/* walk up mux tree */ 398static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr) 399{ 400 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 401 int result; 402 403 result = device_for_each_child(&adapter->dev, &addr, 404 __i2c_check_addr_busy); 405 406 if (!result && parent) 407 result = i2c_check_mux_parents(parent, addr); 408 409 return result; 410} 411 412/* recurse down mux tree */ 413static int i2c_check_mux_children(struct device *dev, void *addrp) 414{ 415 int result; 416 417 if (dev->type == &i2c_adapter_type) 418 result = device_for_each_child(dev, addrp, 419 i2c_check_mux_children); 420 else 421 result = __i2c_check_addr_busy(dev, addrp); 422 423 return result; 424} 425 426static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr) 427{ 428 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 429 int result = 0; 430 431 if (parent) 432 result = i2c_check_mux_parents(parent, addr); 433 434 if (!result) 435 result = device_for_each_child(&adapter->dev, &addr, 436 i2c_check_mux_children); 437 438 return result; 439} 440 441/** 442 * i2c_lock_adapter - Get exclusive access to an I2C bus segment 443 * @adapter: Target I2C bus segment 444 */ 445void i2c_lock_adapter(struct i2c_adapter *adapter) 446{ 447 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 448 449 if (parent) 450 i2c_lock_adapter(parent); 451 else 452 rt_mutex_lock(&adapter->bus_lock); 453} 454EXPORT_SYMBOL_GPL(i2c_lock_adapter); 455 456/** 457 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment 458 * @adapter: Target I2C bus segment 459 */ 460static int i2c_trylock_adapter(struct i2c_adapter *adapter) 461{ 462 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 463 464 if (parent) 465 return i2c_trylock_adapter(parent); 466 else 467 return rt_mutex_trylock(&adapter->bus_lock); 468} 469 470/** 471 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment 472 * @adapter: Target I2C bus segment 473 */ 474void i2c_unlock_adapter(struct i2c_adapter *adapter) 475{ 476 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter); 477 478 if (parent) 479 i2c_unlock_adapter(parent); 480 else 481 rt_mutex_unlock(&adapter->bus_lock); 482} 483EXPORT_SYMBOL_GPL(i2c_unlock_adapter); 484 485/** 486 * i2c_new_device - instantiate an i2c device 487 * @adap: the adapter managing the device 488 * @info: describes one I2C device; bus_num is ignored 489 * Context: can sleep 490 * 491 * Create an i2c device. Binding is handled through driver model 492 * probe()/remove() methods. A driver may be bound to this device when we 493 * return from this function, or any later moment (e.g. maybe hotplugging will 494 * load the driver module). This call is not appropriate for use by mainboard 495 * initialization logic, which usually runs during an arch_initcall() long 496 * before any i2c_adapter could exist. 497 * 498 * This returns the new i2c client, which may be saved for later use with 499 * i2c_unregister_device(); or NULL to indicate an error. 500 */ 501struct i2c_client * 502i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info) 503{ 504 struct i2c_client *client; 505 int status; 506 507 client = kzalloc(sizeof *client, GFP_KERNEL); 508 if (!client) 509 return NULL; 510 511 client->adapter = adap; 512 513 client->dev.platform_data = info->platform_data; 514 515 if (info->archdata) 516 client->dev.archdata = *info->archdata; 517 518 client->flags = info->flags; 519 client->addr = info->addr; 520 client->irq = info->irq; 521 522 strlcpy(client->name, info->type, sizeof(client->name)); 523 524 /* Check for address validity */ 525 status = i2c_check_client_addr_validity(client); 526 if (status) { 527 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n", 528 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr); 529 goto out_err_silent; 530 } 531 532 /* Check for address business */ 533 status = i2c_check_addr_busy(adap, client->addr); 534 if (status) 535 goto out_err; 536 537 client->dev.parent = &client->adapter->dev; 538 client->dev.bus = &i2c_bus_type; 539 client->dev.type = &i2c_client_type; 540 client->dev.of_node = info->of_node; 541 542 /* For 10-bit clients, add an arbitrary offset to avoid collisions */ 543 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap), 544 client->addr | ((client->flags & I2C_CLIENT_TEN) 545 ? 0xa000 : 0)); 546 status = device_register(&client->dev); 547 if (status) 548 goto out_err; 549 550 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n", 551 client->name, dev_name(&client->dev)); 552 553 return client; 554 555out_err: 556 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x " 557 "(%d)\n", client->name, client->addr, status); 558out_err_silent: 559 kfree(client); 560 return NULL; 561} 562EXPORT_SYMBOL_GPL(i2c_new_device); 563 564 565/** 566 * i2c_unregister_device - reverse effect of i2c_new_device() 567 * @client: value returned from i2c_new_device() 568 * Context: can sleep 569 */ 570void i2c_unregister_device(struct i2c_client *client) 571{ 572 device_unregister(&client->dev); 573} 574EXPORT_SYMBOL_GPL(i2c_unregister_device); 575 576 577static const struct i2c_device_id dummy_id[] = { 578 { "dummy", 0 }, 579 { }, 580}; 581 582static int dummy_probe(struct i2c_client *client, 583 const struct i2c_device_id *id) 584{ 585 return 0; 586} 587 588static int dummy_remove(struct i2c_client *client) 589{ 590 return 0; 591} 592 593static struct i2c_driver dummy_driver = { 594 .driver.name = "dummy", 595 .probe = dummy_probe, 596 .remove = dummy_remove, 597 .id_table = dummy_id, 598}; 599 600/** 601 * i2c_new_dummy - return a new i2c device bound to a dummy driver 602 * @adapter: the adapter managing the device 603 * @address: seven bit address to be used 604 * Context: can sleep 605 * 606 * This returns an I2C client bound to the "dummy" driver, intended for use 607 * with devices that consume multiple addresses. Examples of such chips 608 * include various EEPROMS (like 24c04 and 24c08 models). 609 * 610 * These dummy devices have two main uses. First, most I2C and SMBus calls 611 * except i2c_transfer() need a client handle; the dummy will be that handle. 612 * And second, this prevents the specified address from being bound to a 613 * different driver. 614 * 615 * This returns the new i2c client, which should be saved for later use with 616 * i2c_unregister_device(); or NULL to indicate an error. 617 */ 618struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address) 619{ 620 struct i2c_board_info info = { 621 I2C_BOARD_INFO("dummy", address), 622 }; 623 624 return i2c_new_device(adapter, &info); 625} 626EXPORT_SYMBOL_GPL(i2c_new_dummy); 627 628/* ------------------------------------------------------------------------- */ 629 630/* I2C bus adapters -- one roots each I2C or SMBUS segment */ 631 632static void i2c_adapter_dev_release(struct device *dev) 633{ 634 struct i2c_adapter *adap = to_i2c_adapter(dev); 635 complete(&adap->dev_released); 636} 637 638/* 639 * Let users instantiate I2C devices through sysfs. This can be used when 640 * platform initialization code doesn't contain the proper data for 641 * whatever reason. Also useful for drivers that do device detection and 642 * detection fails, either because the device uses an unexpected address, 643 * or this is a compatible device with different ID register values. 644 * 645 * Parameter checking may look overzealous, but we really don't want 646 * the user to provide incorrect parameters. 647 */ 648static ssize_t 649i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr, 650 const char *buf, size_t count) 651{ 652 struct i2c_adapter *adap = to_i2c_adapter(dev); 653 struct i2c_board_info info; 654 struct i2c_client *client; 655 char *blank, end; 656 int res; 657 658 memset(&info, 0, sizeof(struct i2c_board_info)); 659 660 blank = strchr(buf, ' '); 661 if (!blank) { 662 dev_err(dev, "%s: Missing parameters\n", "new_device"); 663 return -EINVAL; 664 } 665 if (blank - buf > I2C_NAME_SIZE - 1) { 666 dev_err(dev, "%s: Invalid device name\n", "new_device"); 667 return -EINVAL; 668 } 669 memcpy(info.type, buf, blank - buf); 670 671 /* Parse remaining parameters, reject extra parameters */ 672 res = sscanf(++blank, "%hi%c", &info.addr, &end); 673 if (res < 1) { 674 dev_err(dev, "%s: Can't parse I2C address\n", "new_device"); 675 return -EINVAL; 676 } 677 if (res > 1 && end != '\n') { 678 dev_err(dev, "%s: Extra parameters\n", "new_device"); 679 return -EINVAL; 680 } 681 682 client = i2c_new_device(adap, &info); 683 if (!client) 684 return -EINVAL; 685 686 /* Keep track of the added device */ 687 mutex_lock(&adap->userspace_clients_lock); 688 list_add_tail(&client->detected, &adap->userspace_clients); 689 mutex_unlock(&adap->userspace_clients_lock); 690 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device", 691 info.type, info.addr); 692 693 return count; 694} 695 696/* 697 * And of course let the users delete the devices they instantiated, if 698 * they got it wrong. This interface can only be used to delete devices 699 * instantiated by i2c_sysfs_new_device above. This guarantees that we 700 * don't delete devices to which some kernel code still has references. 701 * 702 * Parameter checking may look overzealous, but we really don't want 703 * the user to delete the wrong device. 704 */ 705static ssize_t 706i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr, 707 const char *buf, size_t count) 708{ 709 struct i2c_adapter *adap = to_i2c_adapter(dev); 710 struct i2c_client *client, *next; 711 unsigned short addr; 712 char end; 713 int res; 714 715 /* Parse parameters, reject extra parameters */ 716 res = sscanf(buf, "%hi%c", &addr, &end); 717 if (res < 1) { 718 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device"); 719 return -EINVAL; 720 } 721 if (res > 1 && end != '\n') { 722 dev_err(dev, "%s: Extra parameters\n", "delete_device"); 723 return -EINVAL; 724 } 725 726 /* Make sure the device was added through sysfs */ 727 res = -ENOENT; 728 mutex_lock(&adap->userspace_clients_lock); 729 list_for_each_entry_safe(client, next, &adap->userspace_clients, 730 detected) { 731 if (client->addr == addr) { 732 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n", 733 "delete_device", client->name, client->addr); 734 735 list_del(&client->detected); 736 i2c_unregister_device(client); 737 res = count; 738 break; 739 } 740 } 741 mutex_unlock(&adap->userspace_clients_lock); 742 743 if (res < 0) 744 dev_err(dev, "%s: Can't find device in list\n", 745 "delete_device"); 746 return res; 747} 748 749static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device); 750static DEVICE_ATTR(delete_device, S_IWUSR, NULL, i2c_sysfs_delete_device); 751 752static struct attribute *i2c_adapter_attrs[] = { 753 &dev_attr_name.attr, 754 &dev_attr_new_device.attr, 755 &dev_attr_delete_device.attr, 756 NULL 757}; 758 759static struct attribute_group i2c_adapter_attr_group = { 760 .attrs = i2c_adapter_attrs, 761}; 762 763static const struct attribute_group *i2c_adapter_attr_groups[] = { 764 &i2c_adapter_attr_group, 765 NULL 766}; 767 768struct device_type i2c_adapter_type = { 769 .groups = i2c_adapter_attr_groups, 770 .release = i2c_adapter_dev_release, 771}; 772EXPORT_SYMBOL_GPL(i2c_adapter_type); 773 774#ifdef CONFIG_I2C_COMPAT 775static struct class_compat *i2c_adapter_compat_class; 776#endif 777 778static void i2c_scan_static_board_info(struct i2c_adapter *adapter) 779{ 780 struct i2c_devinfo *devinfo; 781 782 down_read(&__i2c_board_lock); 783 list_for_each_entry(devinfo, &__i2c_board_list, list) { 784 if (devinfo->busnum == adapter->nr 785 && !i2c_new_device(adapter, 786 &devinfo->board_info)) 787 dev_err(&adapter->dev, 788 "Can't create device at 0x%02x\n", 789 devinfo->board_info.addr); 790 } 791 up_read(&__i2c_board_lock); 792} 793 794static int i2c_do_add_adapter(struct i2c_driver *driver, 795 struct i2c_adapter *adap) 796{ 797 /* Detect supported devices on that bus, and instantiate them */ 798 i2c_detect(adap, driver); 799 800 /* Let legacy drivers scan this bus for matching devices */ 801 if (driver->attach_adapter) { 802 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n", 803 driver->driver.name); 804 dev_warn(&adap->dev, "Please use another way to instantiate " 805 "your i2c_client\n"); 806 /* We ignore the return code; if it fails, too bad */ 807 driver->attach_adapter(adap); 808 } 809 return 0; 810} 811 812static int __process_new_adapter(struct device_driver *d, void *data) 813{ 814 return i2c_do_add_adapter(to_i2c_driver(d), data); 815} 816 817static int i2c_register_adapter(struct i2c_adapter *adap) 818{ 819 int res = 0; 820 821 /* Can't register until after driver model init */ 822 if (unlikely(WARN_ON(!i2c_bus_type.p))) { 823 res = -EAGAIN; 824 goto out_list; 825 } 826 827 /* Sanity checks */ 828 if (unlikely(adap->name[0] == '\0')) { 829 pr_err("i2c-core: Attempt to register an adapter with " 830 "no name!\n"); 831 return -EINVAL; 832 } 833 if (unlikely(!adap->algo)) { 834 pr_err("i2c-core: Attempt to register adapter '%s' with " 835 "no algo!\n", adap->name); 836 return -EINVAL; 837 } 838 839 rt_mutex_init(&adap->bus_lock); 840 mutex_init(&adap->userspace_clients_lock); 841 INIT_LIST_HEAD(&adap->userspace_clients); 842 843 /* Set default timeout to 1 second if not already set */ 844 if (adap->timeout == 0) 845 adap->timeout = HZ; 846 847 dev_set_name(&adap->dev, "i2c-%d", adap->nr); 848 adap->dev.bus = &i2c_bus_type; 849 adap->dev.type = &i2c_adapter_type; 850 res = device_register(&adap->dev); 851 if (res) 852 goto out_list; 853 854 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name); 855 856#ifdef CONFIG_I2C_COMPAT 857 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev, 858 adap->dev.parent); 859 if (res) 860 dev_warn(&adap->dev, 861 "Failed to create compatibility class link\n"); 862#endif 863 864 /* create pre-declared device nodes */ 865 if (adap->nr < __i2c_first_dynamic_bus_num) 866 i2c_scan_static_board_info(adap); 867 868 /* Notify drivers */ 869 mutex_lock(&core_lock); 870 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter); 871 mutex_unlock(&core_lock); 872 873 return 0; 874 875out_list: 876 mutex_lock(&core_lock); 877 idr_remove(&i2c_adapter_idr, adap->nr); 878 mutex_unlock(&core_lock); 879 return res; 880} 881 882/** 883 * i2c_add_adapter - declare i2c adapter, use dynamic bus number 884 * @adapter: the adapter to add 885 * Context: can sleep 886 * 887 * This routine is used to declare an I2C adapter when its bus number 888 * doesn't matter. Examples: for I2C adapters dynamically added by 889 * USB links or PCI plugin cards. 890 * 891 * When this returns zero, a new bus number was allocated and stored 892 * in adap->nr, and the specified adapter became available for clients. 893 * Otherwise, a negative errno value is returned. 894 */ 895int i2c_add_adapter(struct i2c_adapter *adapter) 896{ 897 int id, res = 0; 898 899retry: 900 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) 901 return -ENOMEM; 902 903 mutex_lock(&core_lock); 904 /* "above" here means "above or equal to", sigh */ 905 res = idr_get_new_above(&i2c_adapter_idr, adapter, 906 __i2c_first_dynamic_bus_num, &id); 907 mutex_unlock(&core_lock); 908 909 if (res < 0) { 910 if (res == -EAGAIN) 911 goto retry; 912 return res; 913 } 914 915 adapter->nr = id; 916 return i2c_register_adapter(adapter); 917} 918EXPORT_SYMBOL(i2c_add_adapter); 919 920/** 921 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number 922 * @adap: the adapter to register (with adap->nr initialized) 923 * Context: can sleep 924 * 925 * This routine is used to declare an I2C adapter when its bus number 926 * matters. For example, use it for I2C adapters from system-on-chip CPUs, 927 * or otherwise built in to the system's mainboard, and where i2c_board_info 928 * is used to properly configure I2C devices. 929 * 930 * If the requested bus number is set to -1, then this function will behave 931 * identically to i2c_add_adapter, and will dynamically assign a bus number. 932 * 933 * If no devices have pre-been declared for this bus, then be sure to 934 * register the adapter before any dynamically allocated ones. Otherwise 935 * the required bus ID may not be available. 936 * 937 * When this returns zero, the specified adapter became available for 938 * clients using the bus number provided in adap->nr. Also, the table 939 * of I2C devices pre-declared using i2c_register_board_info() is scanned, 940 * and the appropriate driver model device nodes are created. Otherwise, a 941 * negative errno value is returned. 942 */ 943int i2c_add_numbered_adapter(struct i2c_adapter *adap) 944{ 945 int id; 946 int status; 947 948 if (adap->nr == -1) /* -1 means dynamically assign bus id */ 949 return i2c_add_adapter(adap); 950 if (adap->nr & ~MAX_ID_MASK) 951 return -EINVAL; 952 953retry: 954 if (idr_pre_get(&i2c_adapter_idr, GFP_KERNEL) == 0) 955 return -ENOMEM; 956 957 mutex_lock(&core_lock); 958 /* "above" here means "above or equal to", sigh; 959 * we need the "equal to" result to force the result 960 */ 961 status = idr_get_new_above(&i2c_adapter_idr, adap, adap->nr, &id); 962 if (status == 0 && id != adap->nr) { 963 status = -EBUSY; 964 idr_remove(&i2c_adapter_idr, id); 965 } 966 mutex_unlock(&core_lock); 967 if (status == -EAGAIN) 968 goto retry; 969 970 if (status == 0) 971 status = i2c_register_adapter(adap); 972 return status; 973} 974EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter); 975 976static int i2c_do_del_adapter(struct i2c_driver *driver, 977 struct i2c_adapter *adapter) 978{ 979 struct i2c_client *client, *_n; 980 int res; 981 982 /* Remove the devices we created ourselves as the result of hardware 983 * probing (using a driver's detect method) */ 984 list_for_each_entry_safe(client, _n, &driver->clients, detected) { 985 if (client->adapter == adapter) { 986 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n", 987 client->name, client->addr); 988 list_del(&client->detected); 989 i2c_unregister_device(client); 990 } 991 } 992 993 if (!driver->detach_adapter) 994 return 0; 995 dev_warn(&adapter->dev, "%s: detach_adapter method is deprecated\n", 996 driver->driver.name); 997 res = driver->detach_adapter(adapter); 998 if (res) 999 dev_err(&adapter->dev, "detach_adapter failed (%d) " 1000 "for driver [%s]\n", res, driver->driver.name); 1001 return res; 1002} 1003 1004static int __unregister_client(struct device *dev, void *dummy) 1005{ 1006 struct i2c_client *client = i2c_verify_client(dev); 1007 if (client && strcmp(client->name, "dummy")) 1008 i2c_unregister_device(client); 1009 return 0; 1010} 1011 1012static int __unregister_dummy(struct device *dev, void *dummy) 1013{ 1014 struct i2c_client *client = i2c_verify_client(dev); 1015 if (client) 1016 i2c_unregister_device(client); 1017 return 0; 1018} 1019 1020static int __process_removed_adapter(struct device_driver *d, void *data) 1021{ 1022 return i2c_do_del_adapter(to_i2c_driver(d), data); 1023} 1024 1025/** 1026 * i2c_del_adapter - unregister I2C adapter 1027 * @adap: the adapter being unregistered 1028 * Context: can sleep 1029 * 1030 * This unregisters an I2C adapter which was previously registered 1031 * by @i2c_add_adapter or @i2c_add_numbered_adapter. 1032 */ 1033int i2c_del_adapter(struct i2c_adapter *adap) 1034{ 1035 int res = 0; 1036 struct i2c_adapter *found; 1037 struct i2c_client *client, *next; 1038 1039 /* First make sure that this adapter was ever added */ 1040 mutex_lock(&core_lock); 1041 found = idr_find(&i2c_adapter_idr, adap->nr); 1042 mutex_unlock(&core_lock); 1043 if (found != adap) { 1044 pr_debug("i2c-core: attempting to delete unregistered " 1045 "adapter [%s]\n", adap->name); 1046 return -EINVAL; 1047 } 1048 1049 /* Tell drivers about this removal */ 1050 mutex_lock(&core_lock); 1051 res = bus_for_each_drv(&i2c_bus_type, NULL, adap, 1052 __process_removed_adapter); 1053 mutex_unlock(&core_lock); 1054 if (res) 1055 return res; 1056 1057 /* Remove devices instantiated from sysfs */ 1058 mutex_lock(&adap->userspace_clients_lock); 1059 list_for_each_entry_safe(client, next, &adap->userspace_clients, 1060 detected) { 1061 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name, 1062 client->addr); 1063 list_del(&client->detected); 1064 i2c_unregister_device(client); 1065 } 1066 mutex_unlock(&adap->userspace_clients_lock); 1067 1068 /* Detach any active clients. This can't fail, thus we do not 1069 * check the returned value. This is a two-pass process, because 1070 * we can't remove the dummy devices during the first pass: they 1071 * could have been instantiated by real devices wishing to clean 1072 * them up properly, so we give them a chance to do that first. */ 1073 res = device_for_each_child(&adap->dev, NULL, __unregister_client); 1074 res = device_for_each_child(&adap->dev, NULL, __unregister_dummy); 1075 1076#ifdef CONFIG_I2C_COMPAT 1077 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev, 1078 adap->dev.parent); 1079#endif 1080 1081 /* device name is gone after device_unregister */ 1082 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name); 1083 1084 /* clean up the sysfs representation */ 1085 init_completion(&adap->dev_released); 1086 device_unregister(&adap->dev); 1087 1088 /* wait for sysfs to drop all references */ 1089 wait_for_completion(&adap->dev_released); 1090 1091 /* free bus id */ 1092 mutex_lock(&core_lock); 1093 idr_remove(&i2c_adapter_idr, adap->nr); 1094 mutex_unlock(&core_lock); 1095 1096 /* Clear the device structure in case this adapter is ever going to be 1097 added again */ 1098 memset(&adap->dev, 0, sizeof(adap->dev)); 1099 1100 return 0; 1101} 1102EXPORT_SYMBOL(i2c_del_adapter); 1103 1104 1105/* ------------------------------------------------------------------------- */ 1106 1107int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *)) 1108{ 1109 int res; 1110 1111 mutex_lock(&core_lock); 1112 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn); 1113 mutex_unlock(&core_lock); 1114 1115 return res; 1116} 1117EXPORT_SYMBOL_GPL(i2c_for_each_dev); 1118 1119static int __process_new_driver(struct device *dev, void *data) 1120{ 1121 if (dev->type != &i2c_adapter_type) 1122 return 0; 1123 return i2c_do_add_adapter(data, to_i2c_adapter(dev)); 1124} 1125 1126/* 1127 * An i2c_driver is used with one or more i2c_client (device) nodes to access 1128 * i2c slave chips, on a bus instance associated with some i2c_adapter. 1129 */ 1130 1131int i2c_register_driver(struct module *owner, struct i2c_driver *driver) 1132{ 1133 int res; 1134 1135 /* Can't register until after driver model init */ 1136 if (unlikely(WARN_ON(!i2c_bus_type.p))) 1137 return -EAGAIN; 1138 1139 /* add the driver to the list of i2c drivers in the driver core */ 1140 driver->driver.owner = owner; 1141 driver->driver.bus = &i2c_bus_type; 1142 1143 /* When registration returns, the driver core 1144 * will have called probe() for all matching-but-unbound devices. 1145 */ 1146 res = driver_register(&driver->driver); 1147 if (res) 1148 return res; 1149 1150 /* Drivers should switch to dev_pm_ops instead. */ 1151 if (driver->suspend) 1152 pr_warn("i2c-core: driver [%s] using legacy suspend method\n", 1153 driver->driver.name); 1154 if (driver->resume) 1155 pr_warn("i2c-core: driver [%s] using legacy resume method\n", 1156 driver->driver.name); 1157 1158 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name); 1159 1160 INIT_LIST_HEAD(&driver->clients); 1161 /* Walk the adapters that are already present */ 1162 i2c_for_each_dev(driver, __process_new_driver); 1163 1164 return 0; 1165} 1166EXPORT_SYMBOL(i2c_register_driver); 1167 1168static int __process_removed_driver(struct device *dev, void *data) 1169{ 1170 if (dev->type != &i2c_adapter_type) 1171 return 0; 1172 return i2c_do_del_adapter(data, to_i2c_adapter(dev)); 1173} 1174 1175/** 1176 * i2c_del_driver - unregister I2C driver 1177 * @driver: the driver being unregistered 1178 * Context: can sleep 1179 */ 1180void i2c_del_driver(struct i2c_driver *driver) 1181{ 1182 i2c_for_each_dev(driver, __process_removed_driver); 1183 1184 driver_unregister(&driver->driver); 1185 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name); 1186} 1187EXPORT_SYMBOL(i2c_del_driver); 1188 1189/* ------------------------------------------------------------------------- */ 1190 1191/** 1192 * i2c_use_client - increments the reference count of the i2c client structure 1193 * @client: the client being referenced 1194 * 1195 * Each live reference to a client should be refcounted. The driver model does 1196 * that automatically as part of driver binding, so that most drivers don't 1197 * need to do this explicitly: they hold a reference until they're unbound 1198 * from the device. 1199 * 1200 * A pointer to the client with the incremented reference counter is returned. 1201 */ 1202struct i2c_client *i2c_use_client(struct i2c_client *client) 1203{ 1204 if (client && get_device(&client->dev)) 1205 return client; 1206 return NULL; 1207} 1208EXPORT_SYMBOL(i2c_use_client); 1209 1210/** 1211 * i2c_release_client - release a use of the i2c client structure 1212 * @client: the client being no longer referenced 1213 * 1214 * Must be called when a user of a client is finished with it. 1215 */ 1216void i2c_release_client(struct i2c_client *client) 1217{ 1218 if (client) 1219 put_device(&client->dev); 1220} 1221EXPORT_SYMBOL(i2c_release_client); 1222 1223struct i2c_cmd_arg { 1224 unsigned cmd; 1225 void *arg; 1226}; 1227 1228static int i2c_cmd(struct device *dev, void *_arg) 1229{ 1230 struct i2c_client *client = i2c_verify_client(dev); 1231 struct i2c_cmd_arg *arg = _arg; 1232 1233 if (client && client->driver && client->driver->command) 1234 client->driver->command(client, arg->cmd, arg->arg); 1235 return 0; 1236} 1237 1238void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg) 1239{ 1240 struct i2c_cmd_arg cmd_arg; 1241 1242 cmd_arg.cmd = cmd; 1243 cmd_arg.arg = arg; 1244 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd); 1245} 1246EXPORT_SYMBOL(i2c_clients_command); 1247 1248static int __init i2c_init(void) 1249{ 1250 int retval; 1251 1252 retval = bus_register(&i2c_bus_type); 1253 if (retval) 1254 return retval; 1255#ifdef CONFIG_I2C_COMPAT 1256 i2c_adapter_compat_class = class_compat_register("i2c-adapter"); 1257 if (!i2c_adapter_compat_class) { 1258 retval = -ENOMEM; 1259 goto bus_err; 1260 } 1261#endif 1262 retval = i2c_add_driver(&dummy_driver); 1263 if (retval) 1264 goto class_err; 1265 return 0; 1266 1267class_err: 1268#ifdef CONFIG_I2C_COMPAT 1269 class_compat_unregister(i2c_adapter_compat_class); 1270bus_err: 1271#endif 1272 bus_unregister(&i2c_bus_type); 1273 return retval; 1274} 1275 1276static void __exit i2c_exit(void) 1277{ 1278 i2c_del_driver(&dummy_driver); 1279#ifdef CONFIG_I2C_COMPAT 1280 class_compat_unregister(i2c_adapter_compat_class); 1281#endif 1282 bus_unregister(&i2c_bus_type); 1283} 1284 1285/* We must initialize early, because some subsystems register i2c drivers 1286 * in subsys_initcall() code, but are linked (and initialized) before i2c. 1287 */ 1288postcore_initcall(i2c_init); 1289module_exit(i2c_exit); 1290 1291/* ---------------------------------------------------- 1292 * the functional interface to the i2c busses. 1293 * ---------------------------------------------------- 1294 */ 1295 1296/** 1297 * i2c_transfer - execute a single or combined I2C message 1298 * @adap: Handle to I2C bus 1299 * @msgs: One or more messages to execute before STOP is issued to 1300 * terminate the operation; each message begins with a START. 1301 * @num: Number of messages to be executed. 1302 * 1303 * Returns negative errno, else the number of messages executed. 1304 * 1305 * Note that there is no requirement that each message be sent to 1306 * the same slave address, although that is the most common model. 1307 */ 1308int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) 1309{ 1310 unsigned long orig_jiffies; 1311 int ret, try; 1312 1313 /* REVISIT the fault reporting model here is weak: 1314 * 1315 * - When we get an error after receiving N bytes from a slave, 1316 * there is no way to report "N". 1317 * 1318 * - When we get a NAK after transmitting N bytes to a slave, 1319 * there is no way to report "N" ... or to let the master 1320 * continue executing the rest of this combined message, if 1321 * that's the appropriate response. 1322 * 1323 * - When for example "num" is two and we successfully complete 1324 * the first message but get an error part way through the 1325 * second, it's unclear whether that should be reported as 1326 * one (discarding status on the second message) or errno 1327 * (discarding status on the first one). 1328 */ 1329 1330 if (adap->algo->master_xfer) { 1331#ifdef DEBUG 1332 for (ret = 0; ret < num; ret++) { 1333 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, " 1334 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD) 1335 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len, 1336 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : ""); 1337 } 1338#endif 1339 1340 if (in_atomic() || irqs_disabled()) { 1341 ret = i2c_trylock_adapter(adap); 1342 if (!ret) 1343 /* I2C activity is ongoing. */ 1344 return -EAGAIN; 1345 } else { 1346 i2c_lock_adapter(adap); 1347 } 1348 1349 /* Retry automatically on arbitration loss */ 1350 orig_jiffies = jiffies; 1351 for (ret = 0, try = 0; try <= adap->retries; try++) { 1352 ret = adap->algo->master_xfer(adap, msgs, num); 1353 if (ret != -EAGAIN) 1354 break; 1355 if (time_after(jiffies, orig_jiffies + adap->timeout)) 1356 break; 1357 } 1358 i2c_unlock_adapter(adap); 1359 1360 return ret; 1361 } else { 1362 dev_dbg(&adap->dev, "I2C level transfers not supported\n"); 1363 return -EOPNOTSUPP; 1364 } 1365} 1366EXPORT_SYMBOL(i2c_transfer); 1367 1368/** 1369 * i2c_master_send - issue a single I2C message in master transmit mode 1370 * @client: Handle to slave device 1371 * @buf: Data that will be written to the slave 1372 * @count: How many bytes to write, must be less than 64k since msg.len is u16 1373 * 1374 * Returns negative errno, or else the number of bytes written. 1375 */ 1376int i2c_master_send(const struct i2c_client *client, const char *buf, int count) 1377{ 1378 int ret; 1379 struct i2c_adapter *adap = client->adapter; 1380 struct i2c_msg msg; 1381 1382 msg.addr = client->addr; 1383 msg.flags = client->flags & I2C_M_TEN; 1384 msg.len = count; 1385 msg.buf = (char *)buf; 1386 1387 ret = i2c_transfer(adap, &msg, 1); 1388 1389 /* If everything went ok (i.e. 1 msg transmitted), return #bytes 1390 transmitted, else error code. */ 1391 return (ret == 1) ? count : ret; 1392} 1393EXPORT_SYMBOL(i2c_master_send); 1394 1395/** 1396 * i2c_master_recv - issue a single I2C message in master receive mode 1397 * @client: Handle to slave device 1398 * @buf: Where to store data read from slave 1399 * @count: How many bytes to read, must be less than 64k since msg.len is u16 1400 * 1401 * Returns negative errno, or else the number of bytes read. 1402 */ 1403int i2c_master_recv(const struct i2c_client *client, char *buf, int count) 1404{ 1405 struct i2c_adapter *adap = client->adapter; 1406 struct i2c_msg msg; 1407 int ret; 1408 1409 msg.addr = client->addr; 1410 msg.flags = client->flags & I2C_M_TEN; 1411 msg.flags |= I2C_M_RD; 1412 msg.len = count; 1413 msg.buf = buf; 1414 1415 ret = i2c_transfer(adap, &msg, 1); 1416 1417 /* If everything went ok (i.e. 1 msg transmitted), return #bytes 1418 transmitted, else error code. */ 1419 return (ret == 1) ? count : ret; 1420} 1421EXPORT_SYMBOL(i2c_master_recv); 1422 1423/* ---------------------------------------------------- 1424 * the i2c address scanning function 1425 * Will not work for 10-bit addresses! 1426 * ---------------------------------------------------- 1427 */ 1428 1429/* 1430 * Legacy default probe function, mostly relevant for SMBus. The default 1431 * probe method is a quick write, but it is known to corrupt the 24RF08 1432 * EEPROMs due to a state machine bug, and could also irreversibly 1433 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f, 1434 * we use a short byte read instead. Also, some bus drivers don't implement 1435 * quick write, so we fallback to a byte read in that case too. 1436 * On x86, there is another special case for FSC hardware monitoring chips, 1437 * which want regular byte reads (address 0x73.) Fortunately, these are the 1438 * only known chips using this I2C address on PC hardware. 1439 * Returns 1 if probe succeeded, 0 if not. 1440 */ 1441static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr) 1442{ 1443 int err; 1444 union i2c_smbus_data dummy; 1445 1446#ifdef CONFIG_X86 1447 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON) 1448 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA)) 1449 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 1450 I2C_SMBUS_BYTE_DATA, &dummy); 1451 else 1452#endif 1453 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50) 1454 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK)) 1455 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0, 1456 I2C_SMBUS_QUICK, NULL); 1457 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE)) 1458 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 1459 I2C_SMBUS_BYTE, &dummy); 1460 else { 1461 dev_warn(&adap->dev, "No suitable probing method supported\n"); 1462 err = -EOPNOTSUPP; 1463 } 1464 1465 return err >= 0; 1466} 1467 1468static int i2c_detect_address(struct i2c_client *temp_client, 1469 struct i2c_driver *driver) 1470{ 1471 struct i2c_board_info info; 1472 struct i2c_adapter *adapter = temp_client->adapter; 1473 int addr = temp_client->addr; 1474 int err; 1475 1476 /* Make sure the address is valid */ 1477 err = i2c_check_addr_validity(addr); 1478 if (err) { 1479 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n", 1480 addr); 1481 return err; 1482 } 1483 1484 /* Skip if already in use */ 1485 if (i2c_check_addr_busy(adapter, addr)) 1486 return 0; 1487 1488 /* Make sure there is something at this address */ 1489 if (!i2c_default_probe(adapter, addr)) 1490 return 0; 1491 1492 /* Finally call the custom detection function */ 1493 memset(&info, 0, sizeof(struct i2c_board_info)); 1494 info.addr = addr; 1495 err = driver->detect(temp_client, &info); 1496 if (err) { 1497 /* -ENODEV is returned if the detection fails. We catch it 1498 here as this isn't an error. */ 1499 return err == -ENODEV ? 0 : err; 1500 } 1501 1502 /* Consistency check */ 1503 if (info.type[0] == '\0') { 1504 dev_err(&adapter->dev, "%s detection function provided " 1505 "no name for 0x%x\n", driver->driver.name, 1506 addr); 1507 } else { 1508 struct i2c_client *client; 1509 1510 /* Detection succeeded, instantiate the device */ 1511 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n", 1512 info.type, info.addr); 1513 client = i2c_new_device(adapter, &info); 1514 if (client) 1515 list_add_tail(&client->detected, &driver->clients); 1516 else 1517 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n", 1518 info.type, info.addr); 1519 } 1520 return 0; 1521} 1522 1523static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver) 1524{ 1525 const unsigned short *address_list; 1526 struct i2c_client *temp_client; 1527 int i, err = 0; 1528 int adap_id = i2c_adapter_id(adapter); 1529 1530 address_list = driver->address_list; 1531 if (!driver->detect || !address_list) 1532 return 0; 1533 1534 /* Stop here if the classes do not match */ 1535 if (!(adapter->class & driver->class)) 1536 return 0; 1537 1538 /* Set up a temporary client to help detect callback */ 1539 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL); 1540 if (!temp_client) 1541 return -ENOMEM; 1542 temp_client->adapter = adapter; 1543 1544 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) { 1545 dev_dbg(&adapter->dev, "found normal entry for adapter %d, " 1546 "addr 0x%02x\n", adap_id, address_list[i]); 1547 temp_client->addr = address_list[i]; 1548 err = i2c_detect_address(temp_client, driver); 1549 if (unlikely(err)) 1550 break; 1551 } 1552 1553 kfree(temp_client); 1554 return err; 1555} 1556 1557int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr) 1558{ 1559 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0, 1560 I2C_SMBUS_QUICK, NULL) >= 0; 1561} 1562EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read); 1563 1564struct i2c_client * 1565i2c_new_probed_device(struct i2c_adapter *adap, 1566 struct i2c_board_info *info, 1567 unsigned short const *addr_list, 1568 int (*probe)(struct i2c_adapter *, unsigned short addr)) 1569{ 1570 int i; 1571 1572 if (!probe) 1573 probe = i2c_default_probe; 1574 1575 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) { 1576 /* Check address validity */ 1577 if (i2c_check_addr_validity(addr_list[i]) < 0) { 1578 dev_warn(&adap->dev, "Invalid 7-bit address " 1579 "0x%02x\n", addr_list[i]); 1580 continue; 1581 } 1582 1583 /* Check address availability */ 1584 if (i2c_check_addr_busy(adap, addr_list[i])) { 1585 dev_dbg(&adap->dev, "Address 0x%02x already in " 1586 "use, not probing\n", addr_list[i]); 1587 continue; 1588 } 1589 1590 /* Test address responsiveness */ 1591 if (probe(adap, addr_list[i])) 1592 break; 1593 } 1594 1595 if (addr_list[i] == I2C_CLIENT_END) { 1596 dev_dbg(&adap->dev, "Probing failed, no device found\n"); 1597 return NULL; 1598 } 1599 1600 info->addr = addr_list[i]; 1601 return i2c_new_device(adap, info); 1602} 1603EXPORT_SYMBOL_GPL(i2c_new_probed_device); 1604 1605struct i2c_adapter *i2c_get_adapter(int nr) 1606{ 1607 struct i2c_adapter *adapter; 1608 1609 mutex_lock(&core_lock); 1610 adapter = idr_find(&i2c_adapter_idr, nr); 1611 if (adapter && !try_module_get(adapter->owner)) 1612 adapter = NULL; 1613 1614 mutex_unlock(&core_lock); 1615 return adapter; 1616} 1617EXPORT_SYMBOL(i2c_get_adapter); 1618 1619void i2c_put_adapter(struct i2c_adapter *adap) 1620{ 1621 module_put(adap->owner); 1622} 1623EXPORT_SYMBOL(i2c_put_adapter); 1624 1625/* The SMBus parts */ 1626 1627#define POLY (0x1070U << 3) 1628static u8 crc8(u16 data) 1629{ 1630 int i; 1631 1632 for (i = 0; i < 8; i++) { 1633 if (data & 0x8000) 1634 data = data ^ POLY; 1635 data = data << 1; 1636 } 1637 return (u8)(data >> 8); 1638} 1639 1640/* Incremental CRC8 over count bytes in the array pointed to by p */ 1641static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count) 1642{ 1643 int i; 1644 1645 for (i = 0; i < count; i++) 1646 crc = crc8((crc ^ p[i]) << 8); 1647 return crc; 1648} 1649 1650/* Assume a 7-bit address, which is reasonable for SMBus */ 1651static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg) 1652{ 1653 /* The address will be sent first */ 1654 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD); 1655 pec = i2c_smbus_pec(pec, &addr, 1); 1656 1657 /* The data buffer follows */ 1658 return i2c_smbus_pec(pec, msg->buf, msg->len); 1659} 1660 1661/* Used for write only transactions */ 1662static inline void i2c_smbus_add_pec(struct i2c_msg *msg) 1663{ 1664 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg); 1665 msg->len++; 1666} 1667 1668/* Return <0 on CRC error 1669 If there was a write before this read (most cases) we need to take the 1670 partial CRC from the write part into account. 1671 Note that this function does modify the message (we need to decrease the 1672 message length to hide the CRC byte from the caller). */ 1673static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg) 1674{ 1675 u8 rpec = msg->buf[--msg->len]; 1676 cpec = i2c_smbus_msg_pec(cpec, msg); 1677 1678 if (rpec != cpec) { 1679 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n", 1680 rpec, cpec); 1681 return -EBADMSG; 1682 } 1683 return 0; 1684} 1685 1686/** 1687 * i2c_smbus_read_byte - SMBus "receive byte" protocol 1688 * @client: Handle to slave device 1689 * 1690 * This executes the SMBus "receive byte" protocol, returning negative errno 1691 * else the byte received from the device. 1692 */ 1693s32 i2c_smbus_read_byte(const struct i2c_client *client) 1694{ 1695 union i2c_smbus_data data; 1696 int status; 1697 1698 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1699 I2C_SMBUS_READ, 0, 1700 I2C_SMBUS_BYTE, &data); 1701 return (status < 0) ? status : data.byte; 1702} 1703EXPORT_SYMBOL(i2c_smbus_read_byte); 1704 1705/** 1706 * i2c_smbus_write_byte - SMBus "send byte" protocol 1707 * @client: Handle to slave device 1708 * @value: Byte to be sent 1709 * 1710 * This executes the SMBus "send byte" protocol, returning negative errno 1711 * else zero on success. 1712 */ 1713s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value) 1714{ 1715 return i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1716 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL); 1717} 1718EXPORT_SYMBOL(i2c_smbus_write_byte); 1719 1720/** 1721 * i2c_smbus_read_byte_data - SMBus "read byte" protocol 1722 * @client: Handle to slave device 1723 * @command: Byte interpreted by slave 1724 * 1725 * This executes the SMBus "read byte" protocol, returning negative errno 1726 * else a data byte received from the device. 1727 */ 1728s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command) 1729{ 1730 union i2c_smbus_data data; 1731 int status; 1732 1733 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1734 I2C_SMBUS_READ, command, 1735 I2C_SMBUS_BYTE_DATA, &data); 1736 return (status < 0) ? status : data.byte; 1737} 1738EXPORT_SYMBOL(i2c_smbus_read_byte_data); 1739 1740/** 1741 * i2c_smbus_write_byte_data - SMBus "write byte" protocol 1742 * @client: Handle to slave device 1743 * @command: Byte interpreted by slave 1744 * @value: Byte being written 1745 * 1746 * This executes the SMBus "write byte" protocol, returning negative errno 1747 * else zero on success. 1748 */ 1749s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command, 1750 u8 value) 1751{ 1752 union i2c_smbus_data data; 1753 data.byte = value; 1754 return i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1755 I2C_SMBUS_WRITE, command, 1756 I2C_SMBUS_BYTE_DATA, &data); 1757} 1758EXPORT_SYMBOL(i2c_smbus_write_byte_data); 1759 1760/** 1761 * i2c_smbus_read_word_data - SMBus "read word" protocol 1762 * @client: Handle to slave device 1763 * @command: Byte interpreted by slave 1764 * 1765 * This executes the SMBus "read word" protocol, returning negative errno 1766 * else a 16-bit unsigned "word" received from the device. 1767 */ 1768s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command) 1769{ 1770 union i2c_smbus_data data; 1771 int status; 1772 1773 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1774 I2C_SMBUS_READ, command, 1775 I2C_SMBUS_WORD_DATA, &data); 1776 return (status < 0) ? status : data.word; 1777} 1778EXPORT_SYMBOL(i2c_smbus_read_word_data); 1779 1780/** 1781 * i2c_smbus_write_word_data - SMBus "write word" protocol 1782 * @client: Handle to slave device 1783 * @command: Byte interpreted by slave 1784 * @value: 16-bit "word" being written 1785 * 1786 * This executes the SMBus "write word" protocol, returning negative errno 1787 * else zero on success. 1788 */ 1789s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command, 1790 u16 value) 1791{ 1792 union i2c_smbus_data data; 1793 data.word = value; 1794 return i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1795 I2C_SMBUS_WRITE, command, 1796 I2C_SMBUS_WORD_DATA, &data); 1797} 1798EXPORT_SYMBOL(i2c_smbus_write_word_data); 1799 1800/** 1801 * i2c_smbus_process_call - SMBus "process call" protocol 1802 * @client: Handle to slave device 1803 * @command: Byte interpreted by slave 1804 * @value: 16-bit "word" being written 1805 * 1806 * This executes the SMBus "process call" protocol, returning negative errno 1807 * else a 16-bit unsigned "word" received from the device. 1808 */ 1809s32 i2c_smbus_process_call(const struct i2c_client *client, u8 command, 1810 u16 value) 1811{ 1812 union i2c_smbus_data data; 1813 int status; 1814 data.word = value; 1815 1816 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1817 I2C_SMBUS_WRITE, command, 1818 I2C_SMBUS_PROC_CALL, &data); 1819 return (status < 0) ? status : data.word; 1820} 1821EXPORT_SYMBOL(i2c_smbus_process_call); 1822 1823/** 1824 * i2c_smbus_read_block_data - SMBus "block read" protocol 1825 * @client: Handle to slave device 1826 * @command: Byte interpreted by slave 1827 * @values: Byte array into which data will be read; big enough to hold 1828 * the data returned by the slave. SMBus allows at most 32 bytes. 1829 * 1830 * This executes the SMBus "block read" protocol, returning negative errno 1831 * else the number of data bytes in the slave's response. 1832 * 1833 * Note that using this function requires that the client's adapter support 1834 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers 1835 * support this; its emulation through I2C messaging relies on a specific 1836 * mechanism (I2C_M_RECV_LEN) which may not be implemented. 1837 */ 1838s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command, 1839 u8 *values) 1840{ 1841 union i2c_smbus_data data; 1842 int status; 1843 1844 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1845 I2C_SMBUS_READ, command, 1846 I2C_SMBUS_BLOCK_DATA, &data); 1847 if (status) 1848 return status; 1849 1850 memcpy(values, &data.block[1], data.block[0]); 1851 return data.block[0]; 1852} 1853EXPORT_SYMBOL(i2c_smbus_read_block_data); 1854 1855/** 1856 * i2c_smbus_write_block_data - SMBus "block write" protocol 1857 * @client: Handle to slave device 1858 * @command: Byte interpreted by slave 1859 * @length: Size of data block; SMBus allows at most 32 bytes 1860 * @values: Byte array which will be written. 1861 * 1862 * This executes the SMBus "block write" protocol, returning negative errno 1863 * else zero on success. 1864 */ 1865s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command, 1866 u8 length, const u8 *values) 1867{ 1868 union i2c_smbus_data data; 1869 1870 if (length > I2C_SMBUS_BLOCK_MAX) 1871 length = I2C_SMBUS_BLOCK_MAX; 1872 data.block[0] = length; 1873 memcpy(&data.block[1], values, length); 1874 return i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1875 I2C_SMBUS_WRITE, command, 1876 I2C_SMBUS_BLOCK_DATA, &data); 1877} 1878EXPORT_SYMBOL(i2c_smbus_write_block_data); 1879 1880/* Returns the number of read bytes */ 1881s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command, 1882 u8 length, u8 *values) 1883{ 1884 union i2c_smbus_data data; 1885 int status; 1886 1887 if (length > I2C_SMBUS_BLOCK_MAX) 1888 length = I2C_SMBUS_BLOCK_MAX; 1889 data.block[0] = length; 1890 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1891 I2C_SMBUS_READ, command, 1892 I2C_SMBUS_I2C_BLOCK_DATA, &data); 1893 if (status < 0) 1894 return status; 1895 1896 memcpy(values, &data.block[1], data.block[0]); 1897 return data.block[0]; 1898} 1899EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data); 1900 1901s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command, 1902 u8 length, const u8 *values) 1903{ 1904 union i2c_smbus_data data; 1905 1906 if (length > I2C_SMBUS_BLOCK_MAX) 1907 length = I2C_SMBUS_BLOCK_MAX; 1908 data.block[0] = length; 1909 memcpy(data.block + 1, values, length); 1910 return i2c_smbus_xfer(client->adapter, client->addr, client->flags, 1911 I2C_SMBUS_WRITE, command, 1912 I2C_SMBUS_I2C_BLOCK_DATA, &data); 1913} 1914EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data); 1915 1916/* Simulate a SMBus command using the i2c protocol 1917 No checking of parameters is done! */ 1918static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, 1919 unsigned short flags, 1920 char read_write, u8 command, int size, 1921 union i2c_smbus_data *data) 1922{ 1923 /* So we need to generate a series of msgs. In the case of writing, we 1924 need to use only one message; when reading, we need two. We initialize 1925 most things with sane defaults, to keep the code below somewhat 1926 simpler. */ 1927 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3]; 1928 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2]; 1929 int num = read_write == I2C_SMBUS_READ ? 2 : 1; 1930 struct i2c_msg msg[2] = { { addr, flags, 1, msgbuf0 }, 1931 { addr, flags | I2C_M_RD, 0, msgbuf1 } 1932 }; 1933 int i; 1934 u8 partial_pec = 0; 1935 int status; 1936 1937 msgbuf0[0] = command; 1938 switch (size) { 1939 case I2C_SMBUS_QUICK: 1940 msg[0].len = 0; 1941 /* Special case: The read/write field is used as data */ 1942 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ? 1943 I2C_M_RD : 0); 1944 num = 1; 1945 break; 1946 case I2C_SMBUS_BYTE: 1947 if (read_write == I2C_SMBUS_READ) { 1948 /* Special case: only a read! */ 1949 msg[0].flags = I2C_M_RD | flags; 1950 num = 1; 1951 } 1952 break; 1953 case I2C_SMBUS_BYTE_DATA: 1954 if (read_write == I2C_SMBUS_READ) 1955 msg[1].len = 1; 1956 else { 1957 msg[0].len = 2; 1958 msgbuf0[1] = data->byte; 1959 } 1960 break; 1961 case I2C_SMBUS_WORD_DATA: 1962 if (read_write == I2C_SMBUS_READ) 1963 msg[1].len = 2; 1964 else { 1965 msg[0].len = 3; 1966 msgbuf0[1] = data->word & 0xff; 1967 msgbuf0[2] = data->word >> 8; 1968 } 1969 break; 1970 case I2C_SMBUS_PROC_CALL: 1971 num = 2; /* Special case */ 1972 read_write = I2C_SMBUS_READ; 1973 msg[0].len = 3; 1974 msg[1].len = 2; 1975 msgbuf0[1] = data->word & 0xff; 1976 msgbuf0[2] = data->word >> 8; 1977 break; 1978 case I2C_SMBUS_BLOCK_DATA: 1979 if (read_write == I2C_SMBUS_READ) { 1980 msg[1].flags |= I2C_M_RECV_LEN; 1981 msg[1].len = 1; /* block length will be added by 1982 the underlying bus driver */ 1983 } else { 1984 msg[0].len = data->block[0] + 2; 1985 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) { 1986 dev_err(&adapter->dev, 1987 "Invalid block write size %d\n", 1988 data->block[0]); 1989 return -EINVAL; 1990 } 1991 for (i = 1; i < msg[0].len; i++) 1992 msgbuf0[i] = data->block[i-1]; 1993 } 1994 break; 1995 case I2C_SMBUS_BLOCK_PROC_CALL: 1996 num = 2; /* Another special case */ 1997 read_write = I2C_SMBUS_READ; 1998 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) { 1999 dev_err(&adapter->dev, 2000 "Invalid block write size %d\n", 2001 data->block[0]); 2002 return -EINVAL; 2003 } 2004 msg[0].len = data->block[0] + 2; 2005 for (i = 1; i < msg[0].len; i++) 2006 msgbuf0[i] = data->block[i-1]; 2007 msg[1].flags |= I2C_M_RECV_LEN; 2008 msg[1].len = 1; /* block length will be added by 2009 the underlying bus driver */ 2010 break; 2011 case I2C_SMBUS_I2C_BLOCK_DATA: 2012 if (read_write == I2C_SMBUS_READ) { 2013 msg[1].len = data->block[0]; 2014 } else { 2015 msg[0].len = data->block[0] + 1; 2016 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) { 2017 dev_err(&adapter->dev, 2018 "Invalid block write size %d\n", 2019 data->block[0]); 2020 return -EINVAL; 2021 } 2022 for (i = 1; i <= data->block[0]; i++) 2023 msgbuf0[i] = data->block[i]; 2024 } 2025 break; 2026 default: 2027 dev_err(&adapter->dev, "Unsupported transaction %d\n", size); 2028 return -EOPNOTSUPP; 2029 } 2030 2031 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK 2032 && size != I2C_SMBUS_I2C_BLOCK_DATA); 2033 if (i) { 2034 /* Compute PEC if first message is a write */ 2035 if (!(msg[0].flags & I2C_M_RD)) { 2036 if (num == 1) /* Write only */ 2037 i2c_smbus_add_pec(&msg[0]); 2038 else /* Write followed by read */ 2039 partial_pec = i2c_smbus_msg_pec(0, &msg[0]); 2040 } 2041 /* Ask for PEC if last message is a read */ 2042 if (msg[num-1].flags & I2C_M_RD) 2043 msg[num-1].len++; 2044 } 2045 2046 status = i2c_transfer(adapter, msg, num); 2047 if (status < 0) 2048 return status; 2049 2050 /* Check PEC if last message is a read */ 2051 if (i && (msg[num-1].flags & I2C_M_RD)) { 2052 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]); 2053 if (status < 0) 2054 return status; 2055 } 2056 2057 if (read_write == I2C_SMBUS_READ) 2058 switch (size) { 2059 case I2C_SMBUS_BYTE: 2060 data->byte = msgbuf0[0]; 2061 break; 2062 case I2C_SMBUS_BYTE_DATA: 2063 data->byte = msgbuf1[0]; 2064 break; 2065 case I2C_SMBUS_WORD_DATA: 2066 case I2C_SMBUS_PROC_CALL: 2067 data->word = msgbuf1[0] | (msgbuf1[1] << 8); 2068 break; 2069 case I2C_SMBUS_I2C_BLOCK_DATA: 2070 for (i = 0; i < data->block[0]; i++) 2071 data->block[i+1] = msgbuf1[i]; 2072 break; 2073 case I2C_SMBUS_BLOCK_DATA: 2074 case I2C_SMBUS_BLOCK_PROC_CALL: 2075 for (i = 0; i < msgbuf1[0] + 1; i++) 2076 data->block[i] = msgbuf1[i]; 2077 break; 2078 } 2079 return 0; 2080} 2081 2082/** 2083 * i2c_smbus_xfer - execute SMBus protocol operations 2084 * @adapter: Handle to I2C bus 2085 * @addr: Address of SMBus slave on that bus 2086 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC) 2087 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE 2088 * @command: Byte interpreted by slave, for protocols which use such bytes 2089 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL 2090 * @data: Data to be read or written 2091 * 2092 * This executes an SMBus protocol operation, and returns a negative 2093 * errno code else zero on success. 2094 */ 2095s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, 2096 char read_write, u8 command, int protocol, 2097 union i2c_smbus_data *data) 2098{ 2099 unsigned long orig_jiffies; 2100 int try; 2101 s32 res; 2102 2103 flags &= I2C_M_TEN | I2C_CLIENT_PEC; 2104 2105 if (adapter->algo->smbus_xfer) { 2106 i2c_lock_adapter(adapter); 2107 2108 /* Retry automatically on arbitration loss */ 2109 orig_jiffies = jiffies; 2110 for (res = 0, try = 0; try <= adapter->retries; try++) { 2111 res = adapter->algo->smbus_xfer(adapter, addr, flags, 2112 read_write, command, 2113 protocol, data); 2114 if (res != -EAGAIN) 2115 break; 2116 if (time_after(jiffies, 2117 orig_jiffies + adapter->timeout)) 2118 break; 2119 } 2120 i2c_unlock_adapter(adapter); 2121 } else 2122 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write, 2123 command, protocol, data); 2124 2125 return res; 2126} 2127EXPORT_SYMBOL(i2c_smbus_xfer); 2128 2129MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>"); 2130MODULE_DESCRIPTION("I2C-Bus main module"); 2131MODULE_LICENSE("GPL"); 2132