drivers/i2c/i2c-core-base.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Linux I2C core
   4  *
   5  * Copyright (C) 1995-99 Simon G. Vogl
   6  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   7  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   8  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   9  *
  10  * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
  11  */
  12
  13 #define pr_fmt(fmt) "i2c-core: " fmt
  14
  15 #include <dt-bindings/i2c/i2c.h>
  16 #include <linux/acpi.h>
  17 #include <linux/clk/clk-conf.h>
  18 #include <linux/completion.h>
  19 #include <linux/delay.h>
  20 #include <linux/err.h>
  21 #include <linux/errno.h>
  22 #include <linux/gpio/consumer.h>
  23 #include <linux/i2c.h>
  24 #include <linux/i2c-smbus.h>
  25 #include <linux/idr.h>
  26 #include <linux/init.h>
  27 #include <linux/irqflags.h>
  28 #include <linux/jump_label.h>
  29 #include <linux/kernel.h>
  30 #include <linux/module.h>
  31 #include <linux/mutex.h>
  32 #include <linux/of_device.h>
  33 #include <linux/of.h>
  34 #include <linux/of_irq.h>
  35 #include <linux/pm_domain.h>
  36 #include <linux/pm_runtime.h>
  37 #include <linux/pm_wakeirq.h>
  38 #include <linux/property.h>
  39 #include <linux/rwsem.h>
  40 #include <linux/slab.h>
  41
  42 #include "i2c-core.h"
  43
  44 #define CREATE_TRACE_POINTS
  45 #include <trace/events/i2c.h>
  46
  47 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
  48 #define I2C_ADDR_OFFSET_SLAVE   0x1000
  49
  50 #define I2C_ADDR_7BITS_MAX      0x77
  51 #define I2C_ADDR_7BITS_COUNT    (I2C_ADDR_7BITS_MAX + 1)
  52
  53 #define I2C_ADDR_DEVICE_ID      0x7c
  54
  55 /*
  56  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  57  * deletion of detected devices are serialized
  58  */
  59 static DEFINE_MUTEX(core_lock);
  60 static DEFINE_IDR(i2c_adapter_idr);
  61
  62 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  63
  64 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
  65 static bool is_registered;
  66
  67 int i2c_transfer_trace_reg(void)
  68 {
  69         static_branch_inc(&i2c_trace_msg_key);
  70         return 0;
  71 }
  72
  73 void i2c_transfer_trace_unreg(void)
  74 {
  75         static_branch_dec(&i2c_trace_msg_key);
  76 }
  77
  78 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  79                                                 const struct i2c_client *client)
  80 {
  81         if (!(id && client))
  82                 return NULL;
  83
  84         while (id->name[0]) {
  85                 if (strcmp(client->name, id->name) == 0)
  86                         return id;
  87                 id++;
  88         }
  89         return NULL;
  90 }
  91 EXPORT_SYMBOL_GPL(i2c_match_id);
  92
  93 static int i2c_device_match(struct device *dev, struct device_driver *drv)
  94 {
  95         struct i2c_client       *client = i2c_verify_client(dev);
  96         struct i2c_driver       *driver;
  97
  98
  99         /* Attempt an OF style match */
 100         if (i2c_of_match_device(drv->of_match_table, client))
 101                 return 1;
 102
 103         /* Then ACPI style match */
 104         if (acpi_driver_match_device(dev, drv))
 105                 return 1;
 106
 107         driver = to_i2c_driver(drv);
 108
 109         /* Finally an I2C match */
 110         if (i2c_match_id(driver->id_table, client))
 111                 return 1;
 112
 113         return 0;
 114 }
 115
 116 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 117 {
 118         struct i2c_client *client = to_i2c_client(dev);
 119         int rc;
 120
 121         rc = of_device_uevent_modalias(dev, env);
 122         if (rc != -ENODEV)
 123                 return rc;
 124
 125         rc = acpi_device_uevent_modalias(dev, env);
 126         if (rc != -ENODEV)
 127                 return rc;
 128
 129         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 130 }
 131
 132 /* i2c bus recovery routines */
 133 static int get_scl_gpio_value(struct i2c_adapter *adap)
 134 {
 135         return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 136 }
 137
 138 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 139 {
 140         gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 141 }
 142
 143 static int get_sda_gpio_value(struct i2c_adapter *adap)
 144 {
 145         return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 146 }
 147
 148 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 149 {
 150         gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 151 }
 152
 153 static int i2c_generic_bus_free(struct i2c_adapter *adap)
 154 {
 155         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 156         int ret = -EOPNOTSUPP;
 157
 158         if (bri->get_bus_free)
 159                 ret = bri->get_bus_free(adap);
 160         else if (bri->get_sda)
 161                 ret = bri->get_sda(adap);
 162
 163         if (ret < 0)
 164                 return ret;
 165
 166         return ret ? 0 : -EBUSY;
 167 }
 168
 169 /*
 170  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 171  * We will generate clock with rate 100 KHz and so duration of both clock levels
 172  * is: delay in ns = (10^6 / 100) / 2
 173  */
 174 #define RECOVERY_NDELAY         5000
 175 #define RECOVERY_CLK_CNT        9
 176
 177 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 178 {
 179         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 180         int i = 0, scl = 1, ret = 0;
 181
 182         if (bri->prepare_recovery)
 183                 bri->prepare_recovery(adap);
 184
 185         /*
 186          * If we can set SDA, we will always create a STOP to ensure additional
 187          * pulses will do no harm. This is achieved by letting SDA follow SCL
 188          * half a cycle later. Check the 'incomplete_write_byte' fault injector
 189          * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
 190          * here for simplicity.
 191          */
 192         bri->set_scl(adap, scl);
 193         ndelay(RECOVERY_NDELAY);
 194         if (bri->set_sda)
 195                 bri->set_sda(adap, scl);
 196         ndelay(RECOVERY_NDELAY / 2);
 197
 198         /*
 199          * By this time SCL is high, as we need to give 9 falling-rising edges
 200          */
 201         while (i++ < RECOVERY_CLK_CNT * 2) {
 202                 if (scl) {
 203                         /* SCL shouldn't be low here */
 204                         if (!bri->get_scl(adap)) {
 205                                 dev_err(&adap->dev,
 206                                         "SCL is stuck low, exit recovery\n");
 207                                 ret = -EBUSY;
 208                                 break;
 209                         }
 210                 }
 211
 212                 scl = !scl;
 213                 bri->set_scl(adap, scl);
 214                 /* Creating STOP again, see above */
 215                 if (scl)  {
 216                         /* Honour minimum tsu:sto */
 217                         ndelay(RECOVERY_NDELAY);
 218                 } else {
 219                         /* Honour minimum tf and thd:dat */
 220                         ndelay(RECOVERY_NDELAY / 2);
 221                 }
 222                 if (bri->set_sda)
 223                         bri->set_sda(adap, scl);
 224                 ndelay(RECOVERY_NDELAY / 2);
 225
 226                 if (scl) {
 227                         ret = i2c_generic_bus_free(adap);
 228                         if (ret == 0)
 229                                 break;
 230                 }
 231         }
 232
 233         /* If we can't check bus status, assume recovery worked */
 234         if (ret == -EOPNOTSUPP)
 235                 ret = 0;
 236
 237         if (bri->unprepare_recovery)
 238                 bri->unprepare_recovery(adap);
 239
 240         return ret;
 241 }
 242 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 243
 244 int i2c_recover_bus(struct i2c_adapter *adap)
 245 {
 246         if (!adap->bus_recovery_info)
 247                 return -EOPNOTSUPP;
 248
 249         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 250         return adap->bus_recovery_info->recover_bus(adap);
 251 }
 252 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 253
 254 static void i2c_init_recovery(struct i2c_adapter *adap)
 255 {
 256         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 257         char *err_str;
 258
 259         if (!bri)
 260                 return;
 261
 262         if (!bri->recover_bus) {
 263                 err_str = "no recover_bus() found";
 264                 goto err;
 265         }
 266
 267         if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 268                 bri->get_scl = get_scl_gpio_value;
 269                 bri->set_scl = set_scl_gpio_value;
 270                 if (bri->sda_gpiod) {
 271                         bri->get_sda = get_sda_gpio_value;
 272                         /* FIXME: add proper flag instead of '0' once available */
 273                         if (gpiod_get_direction(bri->sda_gpiod) == 0)
 274                                 bri->set_sda = set_sda_gpio_value;
 275                 }
 276                 return;
 277         }
 278
 279         if (bri->recover_bus == i2c_generic_scl_recovery) {
 280                 /* Generic SCL recovery */
 281                 if (!bri->set_scl || !bri->get_scl) {
 282                         err_str = "no {get|set}_scl() found";
 283                         goto err;
 284                 }
 285                 if (!bri->set_sda && !bri->get_sda) {
 286                         err_str = "either get_sda() or set_sda() needed";
 287                         goto err;
 288                 }
 289         }
 290
 291         return;
 292  err:
 293         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 294         adap->bus_recovery_info = NULL;
 295 }
 296
 297 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 298 {
 299         struct i2c_adapter *adap = client->adapter;
 300         unsigned int irq;
 301
 302         if (!adap->host_notify_domain)
 303                 return -ENXIO;
 304
 305         if (client->flags & I2C_CLIENT_TEN)
 306                 return -EINVAL;
 307
 308         irq = irq_create_mapping(adap->host_notify_domain, client->addr);
 309
 310         return irq > 0 ? irq : -ENXIO;
 311 }
 312
 313 static int i2c_device_probe(struct device *dev)
 314 {
 315         struct i2c_client       *client = i2c_verify_client(dev);
 316         struct i2c_driver       *driver;
 317         int status;
 318
 319         if (!client)
 320                 return 0;
 321
 322         driver = to_i2c_driver(dev->driver);
 323
 324         client->irq = client->init_irq;
 325
 326         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 327                 int irq = -ENOENT;
 328
 329                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 330                         dev_dbg(dev, "Using Host Notify IRQ\n");
 331                         /* Keep adapter active when Host Notify is required */
 332                         pm_runtime_get_sync(&client->adapter->dev);
 333                         irq = i2c_smbus_host_notify_to_irq(client);
 334                 } else if (dev->of_node) {
 335                         irq = of_irq_get_byname(dev->of_node, "irq");
 336                         if (irq == -EINVAL || irq == -ENODATA)
 337                                 irq = of_irq_get(dev->of_node, 0);
 338                 } else if (ACPI_COMPANION(dev)) {
 339                         irq = i2c_acpi_get_irq(client);
 340                 }
 341                 if (irq == -EPROBE_DEFER)
 342                         return irq;
 343
 344                 if (irq < 0)
 345                         irq = 0;
 346
 347                 client->irq = irq;
 348         }
 349
 350         /*
 351          * An I2C ID table is not mandatory, if and only if, a suitable OF
 352          * or ACPI ID table is supplied for the probing device.
 353          */
 354         if (!driver->id_table &&
 355             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 356             !i2c_of_match_device(dev->driver->of_match_table, client))
 357                 return -ENODEV;
 358
 359         if (client->flags & I2C_CLIENT_WAKE) {
 360                 int wakeirq;
 361
 362                 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 363                 if (wakeirq == -EPROBE_DEFER)
 364                         return wakeirq;
 365
 366                 device_init_wakeup(&client->dev, true);
 367
 368                 if (wakeirq > 0 && wakeirq != client->irq)
 369                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 370                 else if (client->irq > 0)
 371                         status = dev_pm_set_wake_irq(dev, client->irq);
 372                 else
 373                         status = 0;
 374
 375                 if (status)
 376                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 377         }
 378
 379         dev_dbg(dev, "probe\n");
 380
 381         status = of_clk_set_defaults(dev->of_node, false);
 382         if (status < 0)
 383                 goto err_clear_wakeup_irq;
 384
 385         status = dev_pm_domain_attach(&client->dev, true);
 386         if (status)
 387                 goto err_clear_wakeup_irq;
 388
 389         /*
 390          * When there are no more users of probe(),
 391          * rename probe_new to probe.
 392          */
 393         if (driver->probe_new)
 394                 status = driver->probe_new(client);
 395         else if (driver->probe)
 396                 status = driver->probe(client,
 397                                        i2c_match_id(driver->id_table, client));
 398         else
 399                 status = -EINVAL;
 400
 401         if (status)
 402                 goto err_detach_pm_domain;
 403
 404         return 0;
 405
 406 err_detach_pm_domain:
 407         dev_pm_domain_detach(&client->dev, true);
 408 err_clear_wakeup_irq:
 409         dev_pm_clear_wake_irq(&client->dev);
 410         device_init_wakeup(&client->dev, false);
 411         return status;
 412 }
 413
 414 static int i2c_device_remove(struct device *dev)
 415 {
 416         struct i2c_client       *client = i2c_verify_client(dev);
 417         struct i2c_driver       *driver;
 418         int status = 0;
 419
 420         if (!client || !dev->driver)
 421                 return 0;
 422
 423         driver = to_i2c_driver(dev->driver);
 424         if (driver->remove) {
 425                 dev_dbg(dev, "remove\n");
 426                 status = driver->remove(client);
 427         }
 428
 429         dev_pm_domain_detach(&client->dev, true);
 430
 431         dev_pm_clear_wake_irq(&client->dev);
 432         device_init_wakeup(&client->dev, false);
 433
 434         client->irq = 0;
 435         if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 436                 pm_runtime_put(&client->adapter->dev);
 437
 438         return status;
 439 }
 440
 441 static void i2c_device_shutdown(struct device *dev)
 442 {
 443         struct i2c_client *client = i2c_verify_client(dev);
 444         struct i2c_driver *driver;
 445
 446         if (!client || !dev->driver)
 447                 return;
 448         driver = to_i2c_driver(dev->driver);
 449         if (driver->shutdown)
 450                 driver->shutdown(client);
 451 }
 452
 453 static void i2c_client_dev_release(struct device *dev)
 454 {
 455         kfree(to_i2c_client(dev));
 456 }
 457
 458 static ssize_t
 459 name_show(struct device *dev, struct device_attribute *attr, char *buf)
 460 {
 461         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 462                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 463 }
 464 static DEVICE_ATTR_RO(name);
 465
 466 static ssize_t
 467 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
 468 {
 469         struct i2c_client *client = to_i2c_client(dev);
 470         int len;
 471
 472         len = of_device_modalias(dev, buf, PAGE_SIZE);
 473         if (len != -ENODEV)
 474                 return len;
 475
 476         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 477         if (len != -ENODEV)
 478                 return len;
 479
 480         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 481 }
 482 static DEVICE_ATTR_RO(modalias);
 483
 484 static struct attribute *i2c_dev_attrs[] = {
 485         &dev_attr_name.attr,
 486         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 487         &dev_attr_modalias.attr,
 488         NULL
 489 };
 490 ATTRIBUTE_GROUPS(i2c_dev);
 491
 492 struct bus_type i2c_bus_type = {
 493         .name           = "i2c",
 494         .match          = i2c_device_match,
 495         .probe          = i2c_device_probe,
 496         .remove         = i2c_device_remove,
 497         .shutdown       = i2c_device_shutdown,
 498 };
 499 EXPORT_SYMBOL_GPL(i2c_bus_type);
 500
 501 struct device_type i2c_client_type = {
 502         .groups         = i2c_dev_groups,
 503         .uevent         = i2c_device_uevent,
 504         .release        = i2c_client_dev_release,
 505 };
 506 EXPORT_SYMBOL_GPL(i2c_client_type);
 507
 508
 509 /**
 510  * i2c_verify_client - return parameter as i2c_client, or NULL
 511  * @dev: device, probably from some driver model iterator
 512  *
 513  * When traversing the driver model tree, perhaps using driver model
 514  * iterators like @device_for_each_child(), you can't assume very much
 515  * about the nodes you find.  Use this function to avoid oopses caused
 516  * by wrongly treating some non-I2C device as an i2c_client.
 517  */
 518 struct i2c_client *i2c_verify_client(struct device *dev)
 519 {
 520         return (dev->type == &i2c_client_type)
 521                         ? to_i2c_client(dev)
 522                         : NULL;
 523 }
 524 EXPORT_SYMBOL(i2c_verify_client);
 525
 526
 527 /* Return a unique address which takes the flags of the client into account */
 528 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 529 {
 530         unsigned short addr = client->addr;
 531
 532         /* For some client flags, add an arbitrary offset to avoid collisions */
 533         if (client->flags & I2C_CLIENT_TEN)
 534                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 535
 536         if (client->flags & I2C_CLIENT_SLAVE)
 537                 addr |= I2C_ADDR_OFFSET_SLAVE;
 538
 539         return addr;
 540 }
 541
 542 /* This is a permissive address validity check, I2C address map constraints
 543  * are purposely not enforced, except for the general call address. */
 544 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 545 {
 546         if (flags & I2C_CLIENT_TEN) {
 547                 /* 10-bit address, all values are valid */
 548                 if (addr > 0x3ff)
 549                         return -EINVAL;
 550         } else {
 551                 /* 7-bit address, reject the general call address */
 552                 if (addr == 0x00 || addr > 0x7f)
 553                         return -EINVAL;
 554         }
 555         return 0;
 556 }
 557
 558 /* And this is a strict address validity check, used when probing. If a
 559  * device uses a reserved address, then it shouldn't be probed. 7-bit
 560  * addressing is assumed, 10-bit address devices are rare and should be
 561  * explicitly enumerated. */
 562 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 563 {
 564         /*
 565          * Reserved addresses per I2C specification:
 566          *  0x00       General call address / START byte
 567          *  0x01       CBUS address
 568          *  0x02       Reserved for different bus format
 569          *  0x03       Reserved for future purposes
 570          *  0x04-0x07  Hs-mode master code
 571          *  0x78-0x7b  10-bit slave addressing
 572          *  0x7c-0x7f  Reserved for future purposes
 573          */
 574         if (addr < 0x08 || addr > 0x77)
 575                 return -EINVAL;
 576         return 0;
 577 }
 578
 579 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 580 {
 581         struct i2c_client       *client = i2c_verify_client(dev);
 582         int                     addr = *(int *)addrp;
 583
 584         if (client && i2c_encode_flags_to_addr(client) == addr)
 585                 return -EBUSY;
 586         return 0;
 587 }
 588
 589 /* walk up mux tree */
 590 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 591 {
 592         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 593         int result;
 594
 595         result = device_for_each_child(&adapter->dev, &addr,
 596                                         __i2c_check_addr_busy);
 597
 598         if (!result && parent)
 599                 result = i2c_check_mux_parents(parent, addr);
 600
 601         return result;
 602 }
 603
 604 /* recurse down mux tree */
 605 static int i2c_check_mux_children(struct device *dev, void *addrp)
 606 {
 607         int result;
 608
 609         if (dev->type == &i2c_adapter_type)
 610                 result = device_for_each_child(dev, addrp,
 611                                                 i2c_check_mux_children);
 612         else
 613                 result = __i2c_check_addr_busy(dev, addrp);
 614
 615         return result;
 616 }
 617
 618 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 619 {
 620         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 621         int result = 0;
 622
 623         if (parent)
 624                 result = i2c_check_mux_parents(parent, addr);
 625
 626         if (!result)
 627                 result = device_for_each_child(&adapter->dev, &addr,
 628                                                 i2c_check_mux_children);
 629
 630         return result;
 631 }
 632
 633 /**
 634  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 635  * @adapter: Target I2C bus segment
 636  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 637  *      locks only this branch in the adapter tree
 638  */
 639 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 640                                  unsigned int flags)
 641 {
 642         rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 643 }
 644
 645 /**
 646  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 647  * @adapter: Target I2C bus segment
 648  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 649  *      trylocks only this branch in the adapter tree
 650  */
 651 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 652                                    unsigned int flags)
 653 {
 654         return rt_mutex_trylock(&adapter->bus_lock);
 655 }
 656
 657 /**
 658  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 659  * @adapter: Target I2C bus segment
 660  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 661  *      unlocks only this branch in the adapter tree
 662  */
 663 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 664                                    unsigned int flags)
 665 {
 666         rt_mutex_unlock(&adapter->bus_lock);
 667 }
 668
 669 static void i2c_dev_set_name(struct i2c_adapter *adap,
 670                              struct i2c_client *client,
 671                              struct i2c_board_info const *info)
 672 {
 673         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 674
 675         if (info && info->dev_name) {
 676                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 677                 return;
 678         }
 679
 680         if (adev) {
 681                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 682                 return;
 683         }
 684
 685         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 686                      i2c_encode_flags_to_addr(client));
 687 }
 688
 689 int i2c_dev_irq_from_resources(const struct resource *resources,
 690                                unsigned int num_resources)
 691 {
 692         struct irq_data *irqd;
 693         int i;
 694
 695         for (i = 0; i < num_resources; i++) {
 696                 const struct resource *r = &resources[i];
 697
 698                 if (resource_type(r) != IORESOURCE_IRQ)
 699                         continue;
 700
 701                 if (r->flags & IORESOURCE_BITS) {
 702                         irqd = irq_get_irq_data(r->start);
 703                         if (!irqd)
 704                                 break;
 705
 706                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 707                 }
 708
 709                 return r->start;
 710         }
 711
 712         return 0;
 713 }
 714
 715 /**
 716  * i2c_new_client_device - instantiate an i2c device
 717  * @adap: the adapter managing the device
 718  * @info: describes one I2C device; bus_num is ignored
 719  * Context: can sleep
 720  *
 721  * Create an i2c device. Binding is handled through driver model
 722  * probe()/remove() methods.  A driver may be bound to this device when we
 723  * return from this function, or any later moment (e.g. maybe hotplugging will
 724  * load the driver module).  This call is not appropriate for use by mainboard
 725  * initialization logic, which usually runs during an arch_initcall() long
 726  * before any i2c_adapter could exist.
 727  *
 728  * This returns the new i2c client, which may be saved for later use with
 729  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 730  */
 731 struct i2c_client *
 732 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 733 {
 734         struct i2c_client       *client;
 735         int                     status;
 736
 737         client = kzalloc(sizeof *client, GFP_KERNEL);
 738         if (!client)
 739                 return ERR_PTR(-ENOMEM);
 740
 741         client->adapter = adap;
 742
 743         client->dev.platform_data = info->platform_data;
 744         client->flags = info->flags;
 745         client->addr = info->addr;
 746
 747         client->init_irq = info->irq;
 748         if (!client->init_irq)
 749                 client->init_irq = i2c_dev_irq_from_resources(info->resources,
 750                                                          info->num_resources);
 751
 752         strlcpy(client->name, info->type, sizeof(client->name));
 753
 754         status = i2c_check_addr_validity(client->addr, client->flags);
 755         if (status) {
 756                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 757                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 758                 goto out_err_silent;
 759         }
 760
 761         /* Check for address business */
 762         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 763         if (status)
 764                 goto out_err;
 765
 766         client->dev.parent = &client->adapter->dev;
 767         client->dev.bus = &i2c_bus_type;
 768         client->dev.type = &i2c_client_type;
 769         client->dev.of_node = of_node_get(info->of_node);
 770         client->dev.fwnode = info->fwnode;
 771
 772         i2c_dev_set_name(adap, client, info);
 773
 774         if (info->properties) {
 775                 status = device_add_properties(&client->dev, info->properties);
 776                 if (status) {
 777                         dev_err(&adap->dev,
 778                                 "Failed to add properties to client %s: %d\n",
 779                                 client->name, status);
 780                         goto out_err_put_of_node;
 781                 }
 782         }
 783
 784         status = device_register(&client->dev);
 785         if (status)
 786                 goto out_free_props;
 787
 788         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 789                 client->name, dev_name(&client->dev));
 790
 791         return client;
 792
 793 out_free_props:
 794         if (info->properties)
 795                 device_remove_properties(&client->dev);
 796 out_err_put_of_node:
 797         of_node_put(info->of_node);
 798 out_err:
 799         dev_err(&adap->dev,
 800                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 801                 client->name, client->addr, status);
 802 out_err_silent:
 803         kfree(client);
 804         return ERR_PTR(status);
 805 }
 806 EXPORT_SYMBOL_GPL(i2c_new_client_device);
 807
 808 /**
 809  * i2c_new_device - instantiate an i2c device
 810  * @adap: the adapter managing the device
 811  * @info: describes one I2C device; bus_num is ignored
 812  * Context: can sleep
 813  *
 814  * This deprecated function has the same functionality as
 815  * @i2c_new_client_device, it just returns NULL instead of an ERR_PTR in case of
 816  * an error for compatibility with current I2C API. It will be removed once all
 817  * users are converted.
 818  *
 819  * This returns the new i2c client, which may be saved for later use with
 820  * i2c_unregister_device(); or NULL to indicate an error.
 821  */
 822 struct i2c_client *
 823 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 824 {
 825         struct i2c_client *ret;
 826
 827         ret = i2c_new_client_device(adap, info);
 828         return IS_ERR(ret) ? NULL : ret;
 829 }
 830 EXPORT_SYMBOL_GPL(i2c_new_device);
 831
 832
 833 /**
 834  * i2c_unregister_device - reverse effect of i2c_new_*_device()
 835  * @client: value returned from i2c_new_*_device()
 836  * Context: can sleep
 837  */
 838 void i2c_unregister_device(struct i2c_client *client)
 839 {
 840         if (IS_ERR_OR_NULL(client))
 841                 return;
 842
 843         if (client->dev.of_node) {
 844                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 845                 of_node_put(client->dev.of_node);
 846         }
 847
 848         if (ACPI_COMPANION(&client->dev))
 849                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 850         device_unregister(&client->dev);
 851 }
 852 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 853
 854
 855 static const struct i2c_device_id dummy_id[] = {
 856         { "dummy", 0 },
 857         { },
 858 };
 859
 860 static int dummy_probe(struct i2c_client *client,
 861                        const struct i2c_device_id *id)
 862 {
 863         return 0;
 864 }
 865
 866 static int dummy_remove(struct i2c_client *client)
 867 {
 868         return 0;
 869 }
 870
 871 static struct i2c_driver dummy_driver = {
 872         .driver.name    = "dummy",
 873         .probe          = dummy_probe,
 874         .remove         = dummy_remove,
 875         .id_table       = dummy_id,
 876 };
 877
 878 /**
 879  * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 880  * @adapter: the adapter managing the device
 881  * @address: seven bit address to be used
 882  * Context: can sleep
 883  *
 884  * This returns an I2C client bound to the "dummy" driver, intended for use
 885  * with devices that consume multiple addresses.  Examples of such chips
 886  * include various EEPROMS (like 24c04 and 24c08 models).
 887  *
 888  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 889  * except i2c_transfer() need a client handle; the dummy will be that handle.
 890  * And second, this prevents the specified address from being bound to a
 891  * different driver.
 892  *
 893  * This returns the new i2c client, which should be saved for later use with
 894  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 895  */
 896 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
 897 {
 898         struct i2c_board_info info = {
 899                 I2C_BOARD_INFO("dummy", address),
 900         };
 901
 902         return i2c_new_client_device(adapter, &info);
 903 }
 904 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
 905
 906 struct i2c_dummy_devres {
 907         struct i2c_client *client;
 908 };
 909
 910 static void devm_i2c_release_dummy(struct device *dev, void *res)
 911 {
 912         struct i2c_dummy_devres *this = res;
 913
 914         i2c_unregister_device(this->client);
 915 }
 916
 917 /**
 918  * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 919  * @dev: device the managed resource is bound to
 920  * @adapter: the adapter managing the device
 921  * @address: seven bit address to be used
 922  * Context: can sleep
 923  *
 924  * This is the device-managed version of @i2c_new_dummy_device. It returns the
 925  * new i2c client or an ERR_PTR in case of an error.
 926  */
 927 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
 928                                              struct i2c_adapter *adapter,
 929                                              u16 address)
 930 {
 931         struct i2c_dummy_devres *dr;
 932         struct i2c_client *client;
 933
 934         dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
 935         if (!dr)
 936                 return ERR_PTR(-ENOMEM);
 937
 938         client = i2c_new_dummy_device(adapter, address);
 939         if (IS_ERR(client)) {
 940                 devres_free(dr);
 941         } else {
 942                 dr->client = client;
 943                 devres_add(dev, dr);
 944         }
 945
 946         return client;
 947 }
 948 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
 949
 950 /**
 951  * i2c_new_ancillary_device - Helper to get the instantiated secondary address
 952  * and create the associated device
 953  * @client: Handle to the primary client
 954  * @name: Handle to specify which secondary address to get
 955  * @default_addr: Used as a fallback if no secondary address was specified
 956  * Context: can sleep
 957  *
 958  * I2C clients can be composed of multiple I2C slaves bound together in a single
 959  * component. The I2C client driver then binds to the master I2C slave and needs
 960  * to create I2C dummy clients to communicate with all the other slaves.
 961  *
 962  * This function creates and returns an I2C dummy client whose I2C address is
 963  * retrieved from the platform firmware based on the given slave name. If no
 964  * address is specified by the firmware default_addr is used.
 965  *
 966  * On DT-based platforms the address is retrieved from the "reg" property entry
 967  * cell whose "reg-names" value matches the slave name.
 968  *
 969  * This returns the new i2c client, which should be saved for later use with
 970  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 971  */
 972 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
 973                                                 const char *name,
 974                                                 u16 default_addr)
 975 {
 976         struct device_node *np = client->dev.of_node;
 977         u32 addr = default_addr;
 978         int i;
 979
 980         if (np) {
 981                 i = of_property_match_string(np, "reg-names", name);
 982                 if (i >= 0)
 983                         of_property_read_u32_index(np, "reg", i, &addr);
 984         }
 985
 986         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 987         return i2c_new_dummy_device(client->adapter, addr);
 988 }
 989 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
 990
 991 /* ------------------------------------------------------------------------- */
 992
 993 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 994
 995 static void i2c_adapter_dev_release(struct device *dev)
 996 {
 997         struct i2c_adapter *adap = to_i2c_adapter(dev);
 998         complete(&adap->dev_released);
 999 }
1000
1001 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1002 {
1003         unsigned int depth = 0;
1004
1005         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1006                 depth++;
1007
1008         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1009                   "adapter depth exceeds lockdep subclass limit\n");
1010
1011         return depth;
1012 }
1013 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1014
1015 /*
1016  * Let users instantiate I2C devices through sysfs. This can be used when
1017  * platform initialization code doesn't contain the proper data for
1018  * whatever reason. Also useful for drivers that do device detection and
1019  * detection fails, either because the device uses an unexpected address,
1020  * or this is a compatible device with different ID register values.
1021  *
1022  * Parameter checking may look overzealous, but we really don't want
1023  * the user to provide incorrect parameters.
1024  */
1025 static ssize_t
1026 new_device_store(struct device *dev, struct device_attribute *attr,
1027                  const char *buf, size_t count)
1028 {
1029         struct i2c_adapter *adap = to_i2c_adapter(dev);
1030         struct i2c_board_info info;
1031         struct i2c_client *client;
1032         char *blank, end;
1033         int res;
1034
1035         memset(&info, 0, sizeof(struct i2c_board_info));
1036
1037         blank = strchr(buf, ' ');
1038         if (!blank) {
1039                 dev_err(dev, "%s: Missing parameters\n", "new_device");
1040                 return -EINVAL;
1041         }
1042         if (blank - buf > I2C_NAME_SIZE - 1) {
1043                 dev_err(dev, "%s: Invalid device name\n", "new_device");
1044                 return -EINVAL;
1045         }
1046         memcpy(info.type, buf, blank - buf);
1047
1048         /* Parse remaining parameters, reject extra parameters */
1049         res = sscanf(++blank, "%hi%c", &info.addr, &end);
1050         if (res < 1) {
1051                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1052                 return -EINVAL;
1053         }
1054         if (res > 1  && end != '\n') {
1055                 dev_err(dev, "%s: Extra parameters\n", "new_device");
1056                 return -EINVAL;
1057         }
1058
1059         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1060                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1061                 info.flags |= I2C_CLIENT_TEN;
1062         }
1063
1064         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1065                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1066                 info.flags |= I2C_CLIENT_SLAVE;
1067         }
1068
1069         client = i2c_new_client_device(adap, &info);
1070         if (IS_ERR(client))
1071                 return PTR_ERR(client);
1072
1073         /* Keep track of the added device */
1074         mutex_lock(&adap->userspace_clients_lock);
1075         list_add_tail(&client->detected, &adap->userspace_clients);
1076         mutex_unlock(&adap->userspace_clients_lock);
1077         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1078                  info.type, info.addr);
1079
1080         return count;
1081 }
1082 static DEVICE_ATTR_WO(new_device);
1083
1084 /*
1085  * And of course let the users delete the devices they instantiated, if
1086  * they got it wrong. This interface can only be used to delete devices
1087  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1088  * don't delete devices to which some kernel code still has references.
1089  *
1090  * Parameter checking may look overzealous, but we really don't want
1091  * the user to delete the wrong device.
1092  */
1093 static ssize_t
1094 delete_device_store(struct device *dev, struct device_attribute *attr,
1095                     const char *buf, size_t count)
1096 {
1097         struct i2c_adapter *adap = to_i2c_adapter(dev);
1098         struct i2c_client *client, *next;
1099         unsigned short addr;
1100         char end;
1101         int res;
1102
1103         /* Parse parameters, reject extra parameters */
1104         res = sscanf(buf, "%hi%c", &addr, &end);
1105         if (res < 1) {
1106                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1107                 return -EINVAL;
1108         }
1109         if (res > 1  && end != '\n') {
1110                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1111                 return -EINVAL;
1112         }
1113
1114         /* Make sure the device was added through sysfs */
1115         res = -ENOENT;
1116         mutex_lock_nested(&adap->userspace_clients_lock,
1117                           i2c_adapter_depth(adap));
1118         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1119                                  detected) {
1120                 if (i2c_encode_flags_to_addr(client) == addr) {
1121                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1122                                  "delete_device", client->name, client->addr);
1123
1124                         list_del(&client->detected);
1125                         i2c_unregister_device(client);
1126                         res = count;
1127                         break;
1128                 }
1129         }
1130         mutex_unlock(&adap->userspace_clients_lock);
1131
1132         if (res < 0)
1133                 dev_err(dev, "%s: Can't find device in list\n",
1134                         "delete_device");
1135         return res;
1136 }
1137 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1138                                   delete_device_store);
1139
1140 static struct attribute *i2c_adapter_attrs[] = {
1141         &dev_attr_name.attr,
1142         &dev_attr_new_device.attr,
1143         &dev_attr_delete_device.attr,
1144         NULL
1145 };
1146 ATTRIBUTE_GROUPS(i2c_adapter);
1147
1148 struct device_type i2c_adapter_type = {
1149         .groups         = i2c_adapter_groups,
1150         .release        = i2c_adapter_dev_release,
1151 };
1152 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1153
1154 /**
1155  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1156  * @dev: device, probably from some driver model iterator
1157  *
1158  * When traversing the driver model tree, perhaps using driver model
1159  * iterators like @device_for_each_child(), you can't assume very much
1160  * about the nodes you find.  Use this function to avoid oopses caused
1161  * by wrongly treating some non-I2C device as an i2c_adapter.
1162  */
1163 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1164 {
1165         return (dev->type == &i2c_adapter_type)
1166                         ? to_i2c_adapter(dev)
1167                         : NULL;
1168 }
1169 EXPORT_SYMBOL(i2c_verify_adapter);
1170
1171 #ifdef CONFIG_I2C_COMPAT
1172 static struct class_compat *i2c_adapter_compat_class;
1173 #endif
1174
1175 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1176 {
1177         struct i2c_devinfo      *devinfo;
1178
1179         down_read(&__i2c_board_lock);
1180         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1181                 if (devinfo->busnum == adapter->nr &&
1182                     IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1183                         dev_err(&adapter->dev,
1184                                 "Can't create device at 0x%02x\n",
1185                                 devinfo->board_info.addr);
1186         }
1187         up_read(&__i2c_board_lock);
1188 }
1189
1190 static int i2c_do_add_adapter(struct i2c_driver *driver,
1191                               struct i2c_adapter *adap)
1192 {
1193         /* Detect supported devices on that bus, and instantiate them */
1194         i2c_detect(adap, driver);
1195
1196         return 0;
1197 }
1198
1199 static int __process_new_adapter(struct device_driver *d, void *data)
1200 {
1201         return i2c_do_add_adapter(to_i2c_driver(d), data);
1202 }
1203
1204 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1205         .lock_bus =    i2c_adapter_lock_bus,
1206         .trylock_bus = i2c_adapter_trylock_bus,
1207         .unlock_bus =  i2c_adapter_unlock_bus,
1208 };
1209
1210 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1211 {
1212         struct irq_domain *domain = adap->host_notify_domain;
1213         irq_hw_number_t hwirq;
1214
1215         if (!domain)
1216                 return;
1217
1218         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1219                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1220
1221         irq_domain_remove(domain);
1222         adap->host_notify_domain = NULL;
1223 }
1224
1225 static int i2c_host_notify_irq_map(struct irq_domain *h,
1226                                           unsigned int virq,
1227                                           irq_hw_number_t hw_irq_num)
1228 {
1229         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1230
1231         return 0;
1232 }
1233
1234 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1235         .map = i2c_host_notify_irq_map,
1236 };
1237
1238 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1239 {
1240         struct irq_domain *domain;
1241
1242         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1243                 return 0;
1244
1245         domain = irq_domain_create_linear(adap->dev.fwnode,
1246                                           I2C_ADDR_7BITS_COUNT,
1247                                           &i2c_host_notify_irq_ops, adap);
1248         if (!domain)
1249                 return -ENOMEM;
1250
1251         adap->host_notify_domain = domain;
1252
1253         return 0;
1254 }
1255
1256 /**
1257  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1258  * I2C client.
1259  * @adap: the adapter
1260  * @addr: the I2C address of the notifying device
1261  * Context: can't sleep
1262  *
1263  * Helper function to be called from an I2C bus driver's interrupt
1264  * handler. It will schedule the Host Notify IRQ.
1265  */
1266 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1267 {
1268         int irq;
1269
1270         if (!adap)
1271                 return -EINVAL;
1272
1273         irq = irq_find_mapping(adap->host_notify_domain, addr);
1274         if (irq <= 0)
1275                 return -ENXIO;
1276
1277         generic_handle_irq(irq);
1278
1279         return 0;
1280 }
1281 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1282
1283 static int i2c_register_adapter(struct i2c_adapter *adap)
1284 {
1285         int res = -EINVAL;
1286
1287         /* Can't register until after driver model init */
1288         if (WARN_ON(!is_registered)) {
1289                 res = -EAGAIN;
1290                 goto out_list;
1291         }
1292
1293         /* Sanity checks */
1294         if (WARN(!adap->name[0], "i2c adapter has no name"))
1295                 goto out_list;
1296
1297         if (!adap->algo) {
1298                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1299                 goto out_list;
1300         }
1301
1302         if (!adap->lock_ops)
1303                 adap->lock_ops = &i2c_adapter_lock_ops;
1304
1305         adap->locked_flags = 0;
1306         rt_mutex_init(&adap->bus_lock);
1307         rt_mutex_init(&adap->mux_lock);
1308         mutex_init(&adap->userspace_clients_lock);
1309         INIT_LIST_HEAD(&adap->userspace_clients);
1310
1311         /* Set default timeout to 1 second if not already set */
1312         if (adap->timeout == 0)
1313                 adap->timeout = HZ;
1314
1315         /* register soft irqs for Host Notify */
1316         res = i2c_setup_host_notify_irq_domain(adap);
1317         if (res) {
1318                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1319                        adap->name, res);
1320                 goto out_list;
1321         }
1322
1323         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1324         adap->dev.bus = &i2c_bus_type;
1325         adap->dev.type = &i2c_adapter_type;
1326         res = device_register(&adap->dev);
1327         if (res) {
1328                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1329                 goto out_list;
1330         }
1331
1332         res = of_i2c_setup_smbus_alert(adap);
1333         if (res)
1334                 goto out_reg;
1335
1336         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1337
1338         pm_runtime_no_callbacks(&adap->dev);
1339         pm_suspend_ignore_children(&adap->dev, true);
1340         pm_runtime_enable(&adap->dev);
1341
1342 #ifdef CONFIG_I2C_COMPAT
1343         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1344                                        adap->dev.parent);
1345         if (res)
1346                 dev_warn(&adap->dev,
1347                          "Failed to create compatibility class link\n");
1348 #endif
1349
1350         i2c_init_recovery(adap);
1351
1352         /* create pre-declared device nodes */
1353         of_i2c_register_devices(adap);
1354         i2c_acpi_register_devices(adap);
1355         i2c_acpi_install_space_handler(adap);
1356
1357         if (adap->nr < __i2c_first_dynamic_bus_num)
1358                 i2c_scan_static_board_info(adap);
1359
1360         /* Notify drivers */
1361         mutex_lock(&core_lock);
1362         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1363         mutex_unlock(&core_lock);
1364
1365         return 0;
1366
1367 out_reg:
1368         init_completion(&adap->dev_released);
1369         device_unregister(&adap->dev);
1370         wait_for_completion(&adap->dev_released);
1371 out_list:
1372         mutex_lock(&core_lock);
1373         idr_remove(&i2c_adapter_idr, adap->nr);
1374         mutex_unlock(&core_lock);
1375         return res;
1376 }
1377
1378 /**
1379  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1380  * @adap: the adapter to register (with adap->nr initialized)
1381  * Context: can sleep
1382  *
1383  * See i2c_add_numbered_adapter() for details.
1384  */
1385 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1386 {
1387         int id;
1388
1389         mutex_lock(&core_lock);
1390         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1391         mutex_unlock(&core_lock);
1392         if (WARN(id < 0, "couldn't get idr"))
1393                 return id == -ENOSPC ? -EBUSY : id;
1394
1395         return i2c_register_adapter(adap);
1396 }
1397
1398 /**
1399  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1400  * @adapter: the adapter to add
1401  * Context: can sleep
1402  *
1403  * This routine is used to declare an I2C adapter when its bus number
1404  * doesn't matter or when its bus number is specified by an dt alias.
1405  * Examples of bases when the bus number doesn't matter: I2C adapters
1406  * dynamically added by USB links or PCI plugin cards.
1407  *
1408  * When this returns zero, a new bus number was allocated and stored
1409  * in adap->nr, and the specified adapter became available for clients.
1410  * Otherwise, a negative errno value is returned.
1411  */
1412 int i2c_add_adapter(struct i2c_adapter *adapter)
1413 {
1414         struct device *dev = &adapter->dev;
1415         int id;
1416
1417         if (dev->of_node) {
1418                 id = of_alias_get_id(dev->of_node, "i2c");
1419                 if (id >= 0) {
1420                         adapter->nr = id;
1421                         return __i2c_add_numbered_adapter(adapter);
1422                 }
1423         }
1424
1425         mutex_lock(&core_lock);
1426         id = idr_alloc(&i2c_adapter_idr, adapter,
1427                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1428         mutex_unlock(&core_lock);
1429         if (WARN(id < 0, "couldn't get idr"))
1430                 return id;
1431
1432         adapter->nr = id;
1433
1434         return i2c_register_adapter(adapter);
1435 }
1436 EXPORT_SYMBOL(i2c_add_adapter);
1437
1438 /**
1439  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1440  * @adap: the adapter to register (with adap->nr initialized)
1441  * Context: can sleep
1442  *
1443  * This routine is used to declare an I2C adapter when its bus number
1444  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1445  * or otherwise built in to the system's mainboard, and where i2c_board_info
1446  * is used to properly configure I2C devices.
1447  *
1448  * If the requested bus number is set to -1, then this function will behave
1449  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1450  *
1451  * If no devices have pre-been declared for this bus, then be sure to
1452  * register the adapter before any dynamically allocated ones.  Otherwise
1453  * the required bus ID may not be available.
1454  *
1455  * When this returns zero, the specified adapter became available for
1456  * clients using the bus number provided in adap->nr.  Also, the table
1457  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1458  * and the appropriate driver model device nodes are created.  Otherwise, a
1459  * negative errno value is returned.
1460  */
1461 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1462 {
1463         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1464                 return i2c_add_adapter(adap);
1465
1466         return __i2c_add_numbered_adapter(adap);
1467 }
1468 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1469
1470 static void i2c_do_del_adapter(struct i2c_driver *driver,
1471                               struct i2c_adapter *adapter)
1472 {
1473         struct i2c_client *client, *_n;
1474
1475         /* Remove the devices we created ourselves as the result of hardware
1476          * probing (using a driver's detect method) */
1477         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1478                 if (client->adapter == adapter) {
1479                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1480                                 client->name, client->addr);
1481                         list_del(&client->detected);
1482                         i2c_unregister_device(client);
1483                 }
1484         }
1485 }
1486
1487 static int __unregister_client(struct device *dev, void *dummy)
1488 {
1489         struct i2c_client *client = i2c_verify_client(dev);
1490         if (client && strcmp(client->name, "dummy"))
1491                 i2c_unregister_device(client);
1492         return 0;
1493 }
1494
1495 static int __unregister_dummy(struct device *dev, void *dummy)
1496 {
1497         struct i2c_client *client = i2c_verify_client(dev);
1498         i2c_unregister_device(client);
1499         return 0;
1500 }
1501
1502 static int __process_removed_adapter(struct device_driver *d, void *data)
1503 {
1504         i2c_do_del_adapter(to_i2c_driver(d), data);
1505         return 0;
1506 }
1507
1508 /**
1509  * i2c_del_adapter - unregister I2C adapter
1510  * @adap: the adapter being unregistered
1511  * Context: can sleep
1512  *
1513  * This unregisters an I2C adapter which was previously registered
1514  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1515  */
1516 void i2c_del_adapter(struct i2c_adapter *adap)
1517 {
1518         struct i2c_adapter *found;
1519         struct i2c_client *client, *next;
1520
1521         /* First make sure that this adapter was ever added */
1522         mutex_lock(&core_lock);
1523         found = idr_find(&i2c_adapter_idr, adap->nr);
1524         mutex_unlock(&core_lock);
1525         if (found != adap) {
1526                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1527                 return;
1528         }
1529
1530         i2c_acpi_remove_space_handler(adap);
1531         /* Tell drivers about this removal */
1532         mutex_lock(&core_lock);
1533         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1534                                __process_removed_adapter);
1535         mutex_unlock(&core_lock);
1536
1537         /* Remove devices instantiated from sysfs */
1538         mutex_lock_nested(&adap->userspace_clients_lock,
1539                           i2c_adapter_depth(adap));
1540         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1541                                  detected) {
1542                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1543                         client->addr);
1544                 list_del(&client->detected);
1545                 i2c_unregister_device(client);
1546         }
1547         mutex_unlock(&adap->userspace_clients_lock);
1548
1549         /* Detach any active clients. This can't fail, thus we do not
1550          * check the returned value. This is a two-pass process, because
1551          * we can't remove the dummy devices during the first pass: they
1552          * could have been instantiated by real devices wishing to clean
1553          * them up properly, so we give them a chance to do that first. */
1554         device_for_each_child(&adap->dev, NULL, __unregister_client);
1555         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1556
1557 #ifdef CONFIG_I2C_COMPAT
1558         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1559                                  adap->dev.parent);
1560 #endif
1561
1562         /* device name is gone after device_unregister */
1563         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1564
1565         pm_runtime_disable(&adap->dev);
1566
1567         i2c_host_notify_irq_teardown(adap);
1568
1569         /* wait until all references to the device are gone
1570          *
1571          * FIXME: This is old code and should ideally be replaced by an
1572          * alternative which results in decoupling the lifetime of the struct
1573          * device from the i2c_adapter, like spi or netdev do. Any solution
1574          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1575          */
1576         init_completion(&adap->dev_released);
1577         device_unregister(&adap->dev);
1578         wait_for_completion(&adap->dev_released);
1579
1580         /* free bus id */
1581         mutex_lock(&core_lock);
1582         idr_remove(&i2c_adapter_idr, adap->nr);
1583         mutex_unlock(&core_lock);
1584
1585         /* Clear the device structure in case this adapter is ever going to be
1586            added again */
1587         memset(&adap->dev, 0, sizeof(adap->dev));
1588 }
1589 EXPORT_SYMBOL(i2c_del_adapter);
1590
1591 /**
1592  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1593  * @dev: The device to scan for I2C timing properties
1594  * @t: the i2c_timings struct to be filled with values
1595  * @use_defaults: bool to use sane defaults derived from the I2C specification
1596  *                when properties are not found, otherwise use 0
1597  *
1598  * Scan the device for the generic I2C properties describing timing parameters
1599  * for the signal and fill the given struct with the results. If a property was
1600  * not found and use_defaults was true, then maximum timings are assumed which
1601  * are derived from the I2C specification. If use_defaults is not used, the
1602  * results will be 0, so drivers can apply their own defaults later. The latter
1603  * is mainly intended for avoiding regressions of existing drivers which want
1604  * to switch to this function. New drivers almost always should use the defaults.
1605  */
1606
1607 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1608 {
1609         int ret;
1610
1611         memset(t, 0, sizeof(*t));
1612
1613         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1614         if (ret && use_defaults)
1615                 t->bus_freq_hz = 100000;
1616
1617         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1618         if (ret && use_defaults) {
1619                 if (t->bus_freq_hz <= 100000)
1620                         t->scl_rise_ns = 1000;
1621                 else if (t->bus_freq_hz <= 400000)
1622                         t->scl_rise_ns = 300;
1623                 else
1624                         t->scl_rise_ns = 120;
1625         }
1626
1627         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1628         if (ret && use_defaults) {
1629                 if (t->bus_freq_hz <= 400000)
1630                         t->scl_fall_ns = 300;
1631                 else
1632                         t->scl_fall_ns = 120;
1633         }
1634
1635         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1636
1637         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1638         if (ret && use_defaults)
1639                 t->sda_fall_ns = t->scl_fall_ns;
1640
1641         device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1642
1643         device_property_read_u32(dev, "i2c-digital-filter-width-ns",
1644                                  &t->digital_filter_width_ns);
1645
1646         device_property_read_u32(dev, "i2c-analog-filter-cutoff-frequency",
1647                                  &t->analog_filter_cutoff_freq_hz);
1648 }
1649 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1650
1651 /* ------------------------------------------------------------------------- */
1652
1653 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1654 {
1655         int res;
1656
1657         mutex_lock(&core_lock);
1658         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1659         mutex_unlock(&core_lock);
1660
1661         return res;
1662 }
1663 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1664
1665 static int __process_new_driver(struct device *dev, void *data)
1666 {
1667         if (dev->type != &i2c_adapter_type)
1668                 return 0;
1669         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1670 }
1671
1672 /*
1673  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1674  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1675  */
1676
1677 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1678 {
1679         int res;
1680
1681         /* Can't register until after driver model init */
1682         if (WARN_ON(!is_registered))
1683                 return -EAGAIN;
1684
1685         /* add the driver to the list of i2c drivers in the driver core */
1686         driver->driver.owner = owner;
1687         driver->driver.bus = &i2c_bus_type;
1688         INIT_LIST_HEAD(&driver->clients);
1689
1690         /* When registration returns, the driver core
1691          * will have called probe() for all matching-but-unbound devices.
1692          */
1693         res = driver_register(&driver->driver);
1694         if (res)
1695                 return res;
1696
1697         pr_debug("driver [%s] registered\n", driver->driver.name);
1698
1699         /* Walk the adapters that are already present */
1700         i2c_for_each_dev(driver, __process_new_driver);
1701
1702         return 0;
1703 }
1704 EXPORT_SYMBOL(i2c_register_driver);
1705
1706 static int __process_removed_driver(struct device *dev, void *data)
1707 {
1708         if (dev->type == &i2c_adapter_type)
1709                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1710         return 0;
1711 }
1712
1713 /**
1714  * i2c_del_driver - unregister I2C driver
1715  * @driver: the driver being unregistered
1716  * Context: can sleep
1717  */
1718 void i2c_del_driver(struct i2c_driver *driver)
1719 {
1720         i2c_for_each_dev(driver, __process_removed_driver);
1721
1722         driver_unregister(&driver->driver);
1723         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1724 }
1725 EXPORT_SYMBOL(i2c_del_driver);
1726
1727 /* ------------------------------------------------------------------------- */
1728
1729 struct i2c_cmd_arg {
1730         unsigned        cmd;
1731         void            *arg;
1732 };
1733
1734 static int i2c_cmd(struct device *dev, void *_arg)
1735 {
1736         struct i2c_client       *client = i2c_verify_client(dev);
1737         struct i2c_cmd_arg      *arg = _arg;
1738         struct i2c_driver       *driver;
1739
1740         if (!client || !client->dev.driver)
1741                 return 0;
1742
1743         driver = to_i2c_driver(client->dev.driver);
1744         if (driver->command)
1745                 driver->command(client, arg->cmd, arg->arg);
1746         return 0;
1747 }
1748
1749 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1750 {
1751         struct i2c_cmd_arg      cmd_arg;
1752
1753         cmd_arg.cmd = cmd;
1754         cmd_arg.arg = arg;
1755         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1756 }
1757 EXPORT_SYMBOL(i2c_clients_command);
1758
1759 static int __init i2c_init(void)
1760 {
1761         int retval;
1762
1763         retval = of_alias_get_highest_id("i2c");
1764
1765         down_write(&__i2c_board_lock);
1766         if (retval >= __i2c_first_dynamic_bus_num)
1767                 __i2c_first_dynamic_bus_num = retval + 1;
1768         up_write(&__i2c_board_lock);
1769
1770         retval = bus_register(&i2c_bus_type);
1771         if (retval)
1772                 return retval;
1773
1774         is_registered = true;
1775
1776 #ifdef CONFIG_I2C_COMPAT
1777         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1778         if (!i2c_adapter_compat_class) {
1779                 retval = -ENOMEM;
1780                 goto bus_err;
1781         }
1782 #endif
1783         retval = i2c_add_driver(&dummy_driver);
1784         if (retval)
1785                 goto class_err;
1786
1787         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1788                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1789         if (IS_ENABLED(CONFIG_ACPI))
1790                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1791
1792         return 0;
1793
1794 class_err:
1795 #ifdef CONFIG_I2C_COMPAT
1796         class_compat_unregister(i2c_adapter_compat_class);
1797 bus_err:
1798 #endif
1799         is_registered = false;
1800         bus_unregister(&i2c_bus_type);
1801         return retval;
1802 }
1803
1804 static void __exit i2c_exit(void)
1805 {
1806         if (IS_ENABLED(CONFIG_ACPI))
1807                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1808         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1809                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1810         i2c_del_driver(&dummy_driver);
1811 #ifdef CONFIG_I2C_COMPAT
1812         class_compat_unregister(i2c_adapter_compat_class);
1813 #endif
1814         bus_unregister(&i2c_bus_type);
1815         tracepoint_synchronize_unregister();
1816 }
1817
1818 /* We must initialize early, because some subsystems register i2c drivers
1819  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1820  */
1821 postcore_initcall(i2c_init);
1822 module_exit(i2c_exit);
1823
1824 /* ----------------------------------------------------
1825  * the functional interface to the i2c busses.
1826  * ----------------------------------------------------
1827  */
1828
1829 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1830 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1831
1832 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1833 {
1834         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1835                             err_msg, msg->addr, msg->len,
1836                             msg->flags & I2C_M_RD ? "read" : "write");
1837         return -EOPNOTSUPP;
1838 }
1839
1840 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1841 {
1842         const struct i2c_adapter_quirks *q = adap->quirks;
1843         int max_num = q->max_num_msgs, i;
1844         bool do_len_check = true;
1845
1846         if (q->flags & I2C_AQ_COMB) {
1847                 max_num = 2;
1848
1849                 /* special checks for combined messages */
1850                 if (num == 2) {
1851                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1852                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1853
1854                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1855                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1856
1857                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1858                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1859
1860                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1861                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1862
1863                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1864                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1865
1866                         do_len_check = false;
1867                 }
1868         }
1869
1870         if (i2c_quirk_exceeded(num, max_num))
1871                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1872
1873         for (i = 0; i < num; i++) {
1874                 u16 len = msgs[i].len;
1875
1876                 if (msgs[i].flags & I2C_M_RD) {
1877                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1878                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1879
1880                         if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1881                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1882                 } else {
1883                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1884                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1885
1886                         if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1887                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1888                 }
1889         }
1890
1891         return 0;
1892 }
1893
1894 /**
1895  * __i2c_transfer - unlocked flavor of i2c_transfer
1896  * @adap: Handle to I2C bus
1897  * @msgs: One or more messages to execute before STOP is issued to
1898  *      terminate the operation; each message begins with a START.
1899  * @num: Number of messages to be executed.
1900  *
1901  * Returns negative errno, else the number of messages executed.
1902  *
1903  * Adapter lock must be held when calling this function. No debug logging
1904  * takes place. adap->algo->master_xfer existence isn't checked.
1905  */
1906 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1907 {
1908         unsigned long orig_jiffies;
1909         int ret, try;
1910
1911         if (WARN_ON(!msgs || num < 1))
1912                 return -EINVAL;
1913
1914         ret = __i2c_check_suspended(adap);
1915         if (ret)
1916                 return ret;
1917
1918         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1919                 return -EOPNOTSUPP;
1920
1921         /*
1922          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1923          * enabled.  This is an efficient way of keeping the for-loop from
1924          * being executed when not needed.
1925          */
1926         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1927                 int i;
1928                 for (i = 0; i < num; i++)
1929                         if (msgs[i].flags & I2C_M_RD)
1930                                 trace_i2c_read(adap, &msgs[i], i);
1931                         else
1932                                 trace_i2c_write(adap, &msgs[i], i);
1933         }
1934
1935         /* Retry automatically on arbitration loss */
1936         orig_jiffies = jiffies;
1937         for (ret = 0, try = 0; try <= adap->retries; try++) {
1938                 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1939                         ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1940                 else
1941                         ret = adap->algo->master_xfer(adap, msgs, num);
1942
1943                 if (ret != -EAGAIN)
1944                         break;
1945                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1946                         break;
1947         }
1948
1949         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1950                 int i;
1951                 for (i = 0; i < ret; i++)
1952                         if (msgs[i].flags & I2C_M_RD)
1953                                 trace_i2c_reply(adap, &msgs[i], i);
1954                 trace_i2c_result(adap, num, ret);
1955         }
1956
1957         return ret;
1958 }
1959 EXPORT_SYMBOL(__i2c_transfer);
1960
1961 /**
1962  * i2c_transfer - execute a single or combined I2C message
1963  * @adap: Handle to I2C bus
1964  * @msgs: One or more messages to execute before STOP is issued to
1965  *      terminate the operation; each message begins with a START.
1966  * @num: Number of messages to be executed.
1967  *
1968  * Returns negative errno, else the number of messages executed.
1969  *
1970  * Note that there is no requirement that each message be sent to
1971  * the same slave address, although that is the most common model.
1972  */
1973 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1974 {
1975         int ret;
1976
1977         if (!adap->algo->master_xfer) {
1978                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1979                 return -EOPNOTSUPP;
1980         }
1981
1982         /* REVISIT the fault reporting model here is weak:
1983          *
1984          *  - When we get an error after receiving N bytes from a slave,
1985          *    there is no way to report "N".
1986          *
1987          *  - When we get a NAK after transmitting N bytes to a slave,
1988          *    there is no way to report "N" ... or to let the master
1989          *    continue executing the rest of this combined message, if
1990          *    that's the appropriate response.
1991          *
1992          *  - When for example "num" is two and we successfully complete
1993          *    the first message but get an error part way through the
1994          *    second, it's unclear whether that should be reported as
1995          *    one (discarding status on the second message) or errno
1996          *    (discarding status on the first one).
1997          */
1998         ret = __i2c_lock_bus_helper(adap);
1999         if (ret)
2000                 return ret;
2001
2002         ret = __i2c_transfer(adap, msgs, num);
2003         i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2004
2005         return ret;
2006 }
2007 EXPORT_SYMBOL(i2c_transfer);
2008
2009 /**
2010  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2011  *                             to/from a buffer
2012  * @client: Handle to slave device
2013  * @buf: Where the data is stored
2014  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2015  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2016  *
2017  * Returns negative errno, or else the number of bytes transferred.
2018  */
2019 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2020                               int count, u16 flags)
2021 {
2022         int ret;
2023         struct i2c_msg msg = {
2024                 .addr = client->addr,
2025                 .flags = flags | (client->flags & I2C_M_TEN),
2026                 .len = count,
2027                 .buf = buf,
2028         };
2029
2030         ret = i2c_transfer(client->adapter, &msg, 1);
2031
2032         /*
2033          * If everything went ok (i.e. 1 msg transferred), return #bytes
2034          * transferred, else error code.
2035          */
2036         return (ret == 1) ? count : ret;
2037 }
2038 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2039
2040 /**
2041  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2042  * @client: The device to query
2043  * @id: The queried information
2044  *
2045  * Returns negative errno on error, zero on success.
2046  */
2047 int i2c_get_device_id(const struct i2c_client *client,
2048                       struct i2c_device_identity *id)
2049 {
2050         struct i2c_adapter *adap = client->adapter;
2051         union i2c_smbus_data raw_id;
2052         int ret;
2053
2054         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2055                 return -EOPNOTSUPP;
2056
2057         raw_id.block[0] = 3;
2058         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2059                              I2C_SMBUS_READ, client->addr << 1,
2060                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2061         if (ret)
2062                 return ret;
2063
2064         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2065         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2066         id->die_revision = raw_id.block[3] & 0x7;
2067         return 0;
2068 }
2069 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2070
2071 /* ----------------------------------------------------
2072  * the i2c address scanning function
2073  * Will not work for 10-bit addresses!
2074  * ----------------------------------------------------
2075  */
2076
2077 /*
2078  * Legacy default probe function, mostly relevant for SMBus. The default
2079  * probe method is a quick write, but it is known to corrupt the 24RF08
2080  * EEPROMs due to a state machine bug, and could also irreversibly
2081  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2082  * we use a short byte read instead. Also, some bus drivers don't implement
2083  * quick write, so we fallback to a byte read in that case too.
2084  * On x86, there is another special case for FSC hardware monitoring chips,
2085  * which want regular byte reads (address 0x73.) Fortunately, these are the
2086  * only known chips using this I2C address on PC hardware.
2087  * Returns 1 if probe succeeded, 0 if not.
2088  */
2089 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2090 {
2091         int err;
2092         union i2c_smbus_data dummy;
2093
2094 #ifdef CONFIG_X86
2095         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2096          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2097                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2098                                      I2C_SMBUS_BYTE_DATA, &dummy);
2099         else
2100 #endif
2101         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2102          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2103                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2104                                      I2C_SMBUS_QUICK, NULL);
2105         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2106                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2107                                      I2C_SMBUS_BYTE, &dummy);
2108         else {
2109                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2110                          addr);
2111                 err = -EOPNOTSUPP;
2112         }
2113
2114         return err >= 0;
2115 }
2116
2117 static int i2c_detect_address(struct i2c_client *temp_client,
2118                               struct i2c_driver *driver)
2119 {
2120         struct i2c_board_info info;
2121         struct i2c_adapter *adapter = temp_client->adapter;
2122         int addr = temp_client->addr;
2123         int err;
2124
2125         /* Make sure the address is valid */
2126         err = i2c_check_7bit_addr_validity_strict(addr);
2127         if (err) {
2128                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2129                          addr);
2130                 return err;
2131         }
2132
2133         /* Skip if already in use (7 bit, no need to encode flags) */
2134         if (i2c_check_addr_busy(adapter, addr))
2135                 return 0;
2136
2137         /* Make sure there is something at this address */
2138         if (!i2c_default_probe(adapter, addr))
2139                 return 0;
2140
2141         /* Finally call the custom detection function */
2142         memset(&info, 0, sizeof(struct i2c_board_info));
2143         info.addr = addr;
2144         err = driver->detect(temp_client, &info);
2145         if (err) {
2146                 /* -ENODEV is returned if the detection fails. We catch it
2147                    here as this isn't an error. */
2148                 return err == -ENODEV ? 0 : err;
2149         }
2150
2151         /* Consistency check */
2152         if (info.type[0] == '\0') {
2153                 dev_err(&adapter->dev,
2154                         "%s detection function provided no name for 0x%x\n",
2155                         driver->driver.name, addr);
2156         } else {
2157                 struct i2c_client *client;
2158
2159                 /* Detection succeeded, instantiate the device */
2160                 if (adapter->class & I2C_CLASS_DEPRECATED)
2161                         dev_warn(&adapter->dev,
2162                                 "This adapter will soon drop class based instantiation of devices. "
2163                                 "Please make sure client 0x%02x gets instantiated by other means. "
2164                                 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2165                                 info.addr);
2166
2167                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2168                         info.type, info.addr);
2169                 client = i2c_new_client_device(adapter, &info);
2170                 if (!IS_ERR(client))
2171                         list_add_tail(&client->detected, &driver->clients);
2172                 else
2173                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2174                                 info.type, info.addr);
2175         }
2176         return 0;
2177 }
2178
2179 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2180 {
2181         const unsigned short *address_list;
2182         struct i2c_client *temp_client;
2183         int i, err = 0;
2184         int adap_id = i2c_adapter_id(adapter);
2185
2186         address_list = driver->address_list;
2187         if (!driver->detect || !address_list)
2188                 return 0;
2189
2190         /* Warn that the adapter lost class based instantiation */
2191         if (adapter->class == I2C_CLASS_DEPRECATED) {
2192                 dev_dbg(&adapter->dev,
2193                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2194                         "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2195                         driver->driver.name);
2196                 return 0;
2197         }
2198
2199         /* Stop here if the classes do not match */
2200         if (!(adapter->class & driver->class))
2201                 return 0;
2202
2203         /* Set up a temporary client to help detect callback */
2204         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2205         if (!temp_client)
2206                 return -ENOMEM;
2207         temp_client->adapter = adapter;
2208
2209         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2210                 dev_dbg(&adapter->dev,
2211                         "found normal entry for adapter %d, addr 0x%02x\n",
2212                         adap_id, address_list[i]);
2213                 temp_client->addr = address_list[i];
2214                 err = i2c_detect_address(temp_client, driver);
2215                 if (unlikely(err))
2216                         break;
2217         }
2218
2219         kfree(temp_client);
2220         return err;
2221 }
2222
2223 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2224 {
2225         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2226                               I2C_SMBUS_QUICK, NULL) >= 0;
2227 }
2228 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2229
2230 struct i2c_client *
2231 i2c_new_scanned_device(struct i2c_adapter *adap,
2232                        struct i2c_board_info *info,
2233                        unsigned short const *addr_list,
2234                        int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2235 {
2236         int i;
2237
2238         if (!probe)
2239                 probe = i2c_default_probe;
2240
2241         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2242                 /* Check address validity */
2243                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2244                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2245                                  addr_list[i]);
2246                         continue;
2247                 }
2248
2249                 /* Check address availability (7 bit, no need to encode flags) */
2250                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2251                         dev_dbg(&adap->dev,
2252                                 "Address 0x%02x already in use, not probing\n",
2253                                 addr_list[i]);
2254                         continue;
2255                 }
2256
2257                 /* Test address responsiveness */
2258                 if (probe(adap, addr_list[i]))
2259                         break;
2260         }
2261
2262         if (addr_list[i] == I2C_CLIENT_END) {
2263                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2264                 return ERR_PTR(-ENODEV);
2265         }
2266
2267         info->addr = addr_list[i];
2268         return i2c_new_client_device(adap, info);
2269 }
2270 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2271
2272 struct i2c_client *
2273 i2c_new_probed_device(struct i2c_adapter *adap,
2274                       struct i2c_board_info *info,
2275                       unsigned short const *addr_list,
2276                       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2277 {
2278         struct i2c_client *client;
2279
2280         client = i2c_new_scanned_device(adap, info, addr_list, probe);
2281         return IS_ERR(client) ? NULL : client;
2282 }
2283 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2284
2285 struct i2c_adapter *i2c_get_adapter(int nr)
2286 {
2287         struct i2c_adapter *adapter;
2288
2289         mutex_lock(&core_lock);
2290         adapter = idr_find(&i2c_adapter_idr, nr);
2291         if (!adapter)
2292                 goto exit;
2293
2294         if (try_module_get(adapter->owner))
2295                 get_device(&adapter->dev);
2296         else
2297                 adapter = NULL;
2298
2299  exit:
2300         mutex_unlock(&core_lock);
2301         return adapter;
2302 }
2303 EXPORT_SYMBOL(i2c_get_adapter);
2304
2305 void i2c_put_adapter(struct i2c_adapter *adap)
2306 {
2307         if (!adap)
2308                 return;
2309
2310         put_device(&adap->dev);
2311         module_put(adap->owner);
2312 }
2313 EXPORT_SYMBOL(i2c_put_adapter);
2314
2315 /**
2316  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2317  * @msg: the message to be checked
2318  * @threshold: the minimum number of bytes for which using DMA makes sense.
2319  *             Should at least be 1.
2320  *
2321  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2322  *         Or a valid pointer to be used with DMA. After use, release it by
2323  *         calling i2c_put_dma_safe_msg_buf().
2324  *
2325  * This function must only be called from process context!
2326  */
2327 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2328 {
2329         /* also skip 0-length msgs for bogus thresholds of 0 */
2330         if (!threshold)
2331                 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2332                          msg->addr);
2333         if (msg->len < threshold || msg->len == 0)
2334                 return NULL;
2335
2336         if (msg->flags & I2C_M_DMA_SAFE)
2337                 return msg->buf;
2338
2339         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2340                  msg->addr, msg->len);
2341
2342         if (msg->flags & I2C_M_RD)
2343                 return kzalloc(msg->len, GFP_KERNEL);
2344         else
2345                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2346 }
2347 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2348
2349 /**
2350  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2351  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2352  * @msg: the message which the buffer corresponds to
2353  * @xferred: bool saying if the message was transferred
2354  */
2355 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2356 {
2357         if (!buf || buf == msg->buf)
2358                 return;
2359
2360         if (xferred && msg->flags & I2C_M_RD)
2361                 memcpy(msg->buf, buf, msg->len);
2362
2363         kfree(buf);
2364 }
2365 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2366
2367 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2368 MODULE_DESCRIPTION("I2C-Bus main module");
2369 MODULE_LICENSE("GPL");