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.
 190          */
 191         bri->set_scl(adap, scl);
 192         ndelay(RECOVERY_NDELAY / 2);
 193         if (bri->set_sda)
 194                 bri->set_sda(adap, scl);
 195         ndelay(RECOVERY_NDELAY / 2);
 196
 197         /*
 198          * By this time SCL is high, as we need to give 9 falling-rising edges
 199          */
 200         while (i++ < RECOVERY_CLK_CNT * 2) {
 201                 if (scl) {
 202                         /* SCL shouldn't be low here */
 203                         if (!bri->get_scl(adap)) {
 204                                 dev_err(&adap->dev,
 205                                         "SCL is stuck low, exit recovery\n");
 206                                 ret = -EBUSY;
 207                                 break;
 208                         }
 209                 }
 210
 211                 scl = !scl;
 212                 bri->set_scl(adap, scl);
 213                 /* Creating STOP again, see above */
 214                 ndelay(RECOVERY_NDELAY / 2);
 215                 if (bri->set_sda)
 216                         bri->set_sda(adap, scl);
 217                 ndelay(RECOVERY_NDELAY / 2);
 218
 219                 if (scl) {
 220                         ret = i2c_generic_bus_free(adap);
 221                         if (ret == 0)
 222                                 break;
 223                 }
 224         }
 225
 226         /* If we can't check bus status, assume recovery worked */
 227         if (ret == -EOPNOTSUPP)
 228                 ret = 0;
 229
 230         if (bri->unprepare_recovery)
 231                 bri->unprepare_recovery(adap);
 232
 233         return ret;
 234 }
 235 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 236
 237 int i2c_recover_bus(struct i2c_adapter *adap)
 238 {
 239         if (!adap->bus_recovery_info)
 240                 return -EOPNOTSUPP;
 241
 242         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 243         return adap->bus_recovery_info->recover_bus(adap);
 244 }
 245 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 246
 247 static void i2c_init_recovery(struct i2c_adapter *adap)
 248 {
 249         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 250         char *err_str;
 251
 252         if (!bri)
 253                 return;
 254
 255         if (!bri->recover_bus) {
 256                 err_str = "no recover_bus() found";
 257                 goto err;
 258         }
 259
 260         if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 261                 bri->get_scl = get_scl_gpio_value;
 262                 bri->set_scl = set_scl_gpio_value;
 263                 if (bri->sda_gpiod) {
 264                         bri->get_sda = get_sda_gpio_value;
 265                         /* FIXME: add proper flag instead of '0' once available */
 266                         if (gpiod_get_direction(bri->sda_gpiod) == 0)
 267                                 bri->set_sda = set_sda_gpio_value;
 268                 }
 269                 return;
 270         }
 271
 272         if (bri->recover_bus == i2c_generic_scl_recovery) {
 273                 /* Generic SCL recovery */
 274                 if (!bri->set_scl || !bri->get_scl) {
 275                         err_str = "no {get|set}_scl() found";
 276                         goto err;
 277                 }
 278                 if (!bri->set_sda && !bri->get_sda) {
 279                         err_str = "either get_sda() or set_sda() needed";
 280                         goto err;
 281                 }
 282         }
 283
 284         return;
 285  err:
 286         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 287         adap->bus_recovery_info = NULL;
 288 }
 289
 290 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 291 {
 292         struct i2c_adapter *adap = client->adapter;
 293         unsigned int irq;
 294
 295         if (!adap->host_notify_domain)
 296                 return -ENXIO;
 297
 298         if (client->flags & I2C_CLIENT_TEN)
 299                 return -EINVAL;
 300
 301         irq = irq_create_mapping(adap->host_notify_domain, client->addr);
 302
 303         return irq > 0 ? irq : -ENXIO;
 304 }
 305
 306 static int i2c_device_probe(struct device *dev)
 307 {
 308         struct i2c_client       *client = i2c_verify_client(dev);
 309         struct i2c_driver       *driver;
 310         int status;
 311
 312         if (!client)
 313                 return 0;
 314
 315         driver = to_i2c_driver(dev->driver);
 316
 317         client->irq = client->init_irq;
 318
 319         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 320                 int irq = -ENOENT;
 321
 322                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 323                         dev_dbg(dev, "Using Host Notify IRQ\n");
 324                         /* Keep adapter active when Host Notify is required */
 325                         pm_runtime_get_sync(&client->adapter->dev);
 326                         irq = i2c_smbus_host_notify_to_irq(client);
 327                 } else if (dev->of_node) {
 328                         irq = of_irq_get_byname(dev->of_node, "irq");
 329                         if (irq == -EINVAL || irq == -ENODATA)
 330                                 irq = of_irq_get(dev->of_node, 0);
 331                 } else if (ACPI_COMPANION(dev)) {
 332                         irq = i2c_acpi_get_irq(client);
 333                 }
 334                 if (irq == -EPROBE_DEFER)
 335                         return irq;
 336
 337                 if (irq < 0)
 338                         irq = 0;
 339
 340                 client->irq = irq;
 341         }
 342
 343         /*
 344          * An I2C ID table is not mandatory, if and only if, a suitable OF
 345          * or ACPI ID table is supplied for the probing device.
 346          */
 347         if (!driver->id_table &&
 348             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 349             !i2c_of_match_device(dev->driver->of_match_table, client))
 350                 return -ENODEV;
 351
 352         if (client->flags & I2C_CLIENT_WAKE) {
 353                 int wakeirq = -ENOENT;
 354
 355                 if (dev->of_node) {
 356                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 357                         if (wakeirq == -EPROBE_DEFER)
 358                                 return wakeirq;
 359                 }
 360
 361                 device_init_wakeup(&client->dev, true);
 362
 363                 if (wakeirq > 0 && wakeirq != client->irq)
 364                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 365                 else if (client->irq > 0)
 366                         status = dev_pm_set_wake_irq(dev, client->irq);
 367                 else
 368                         status = 0;
 369
 370                 if (status)
 371                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 372         }
 373
 374         dev_dbg(dev, "probe\n");
 375
 376         status = of_clk_set_defaults(dev->of_node, false);
 377         if (status < 0)
 378                 goto err_clear_wakeup_irq;
 379
 380         status = dev_pm_domain_attach(&client->dev, true);
 381         if (status)
 382                 goto err_clear_wakeup_irq;
 383
 384         /*
 385          * When there are no more users of probe(),
 386          * rename probe_new to probe.
 387          */
 388         if (driver->probe_new)
 389                 status = driver->probe_new(client);
 390         else if (driver->probe)
 391                 status = driver->probe(client,
 392                                        i2c_match_id(driver->id_table, client));
 393         else
 394                 status = -EINVAL;
 395
 396         if (status)
 397                 goto err_detach_pm_domain;
 398
 399         return 0;
 400
 401 err_detach_pm_domain:
 402         dev_pm_domain_detach(&client->dev, true);
 403 err_clear_wakeup_irq:
 404         dev_pm_clear_wake_irq(&client->dev);
 405         device_init_wakeup(&client->dev, false);
 406         return status;
 407 }
 408
 409 static int i2c_device_remove(struct device *dev)
 410 {
 411         struct i2c_client       *client = i2c_verify_client(dev);
 412         struct i2c_driver       *driver;
 413         int status = 0;
 414
 415         if (!client || !dev->driver)
 416                 return 0;
 417
 418         driver = to_i2c_driver(dev->driver);
 419         if (driver->remove) {
 420                 dev_dbg(dev, "remove\n");
 421                 status = driver->remove(client);
 422         }
 423
 424         dev_pm_domain_detach(&client->dev, true);
 425
 426         dev_pm_clear_wake_irq(&client->dev);
 427         device_init_wakeup(&client->dev, false);
 428
 429         client->irq = 0;
 430         if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 431                 pm_runtime_put(&client->adapter->dev);
 432
 433         return status;
 434 }
 435
 436 static void i2c_device_shutdown(struct device *dev)
 437 {
 438         struct i2c_client *client = i2c_verify_client(dev);
 439         struct i2c_driver *driver;
 440
 441         if (!client || !dev->driver)
 442                 return;
 443         driver = to_i2c_driver(dev->driver);
 444         if (driver->shutdown)
 445                 driver->shutdown(client);
 446 }
 447
 448 static void i2c_client_dev_release(struct device *dev)
 449 {
 450         kfree(to_i2c_client(dev));
 451 }
 452
 453 static ssize_t
 454 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 455 {
 456         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 457                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 458 }
 459 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 460
 461 static ssize_t
 462 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 463 {
 464         struct i2c_client *client = to_i2c_client(dev);
 465         int len;
 466
 467         len = of_device_modalias(dev, buf, PAGE_SIZE);
 468         if (len != -ENODEV)
 469                 return len;
 470
 471         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 472         if (len != -ENODEV)
 473                 return len;
 474
 475         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 476 }
 477 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 478
 479 static struct attribute *i2c_dev_attrs[] = {
 480         &dev_attr_name.attr,
 481         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 482         &dev_attr_modalias.attr,
 483         NULL
 484 };
 485 ATTRIBUTE_GROUPS(i2c_dev);
 486
 487 struct bus_type i2c_bus_type = {
 488         .name           = "i2c",
 489         .match          = i2c_device_match,
 490         .probe          = i2c_device_probe,
 491         .remove         = i2c_device_remove,
 492         .shutdown       = i2c_device_shutdown,
 493 };
 494 EXPORT_SYMBOL_GPL(i2c_bus_type);
 495
 496 struct device_type i2c_client_type = {
 497         .groups         = i2c_dev_groups,
 498         .uevent         = i2c_device_uevent,
 499         .release        = i2c_client_dev_release,
 500 };
 501 EXPORT_SYMBOL_GPL(i2c_client_type);
 502
 503
 504 /**
 505  * i2c_verify_client - return parameter as i2c_client, or NULL
 506  * @dev: device, probably from some driver model iterator
 507  *
 508  * When traversing the driver model tree, perhaps using driver model
 509  * iterators like @device_for_each_child(), you can't assume very much
 510  * about the nodes you find.  Use this function to avoid oopses caused
 511  * by wrongly treating some non-I2C device as an i2c_client.
 512  */
 513 struct i2c_client *i2c_verify_client(struct device *dev)
 514 {
 515         return (dev->type == &i2c_client_type)
 516                         ? to_i2c_client(dev)
 517                         : NULL;
 518 }
 519 EXPORT_SYMBOL(i2c_verify_client);
 520
 521
 522 /* Return a unique address which takes the flags of the client into account */
 523 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 524 {
 525         unsigned short addr = client->addr;
 526
 527         /* For some client flags, add an arbitrary offset to avoid collisions */
 528         if (client->flags & I2C_CLIENT_TEN)
 529                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 530
 531         if (client->flags & I2C_CLIENT_SLAVE)
 532                 addr |= I2C_ADDR_OFFSET_SLAVE;
 533
 534         return addr;
 535 }
 536
 537 /* This is a permissive address validity check, I2C address map constraints
 538  * are purposely not enforced, except for the general call address. */
 539 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 540 {
 541         if (flags & I2C_CLIENT_TEN) {
 542                 /* 10-bit address, all values are valid */
 543                 if (addr > 0x3ff)
 544                         return -EINVAL;
 545         } else {
 546                 /* 7-bit address, reject the general call address */
 547                 if (addr == 0x00 || addr > 0x7f)
 548                         return -EINVAL;
 549         }
 550         return 0;
 551 }
 552
 553 /* And this is a strict address validity check, used when probing. If a
 554  * device uses a reserved address, then it shouldn't be probed. 7-bit
 555  * addressing is assumed, 10-bit address devices are rare and should be
 556  * explicitly enumerated. */
 557 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 558 {
 559         /*
 560          * Reserved addresses per I2C specification:
 561          *  0x00       General call address / START byte
 562          *  0x01       CBUS address
 563          *  0x02       Reserved for different bus format
 564          *  0x03       Reserved for future purposes
 565          *  0x04-0x07  Hs-mode master code
 566          *  0x78-0x7b  10-bit slave addressing
 567          *  0x7c-0x7f  Reserved for future purposes
 568          */
 569         if (addr < 0x08 || addr > 0x77)
 570                 return -EINVAL;
 571         return 0;
 572 }
 573
 574 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 575 {
 576         struct i2c_client       *client = i2c_verify_client(dev);
 577         int                     addr = *(int *)addrp;
 578
 579         if (client && i2c_encode_flags_to_addr(client) == addr)
 580                 return -EBUSY;
 581         return 0;
 582 }
 583
 584 /* walk up mux tree */
 585 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 586 {
 587         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 588         int result;
 589
 590         result = device_for_each_child(&adapter->dev, &addr,
 591                                         __i2c_check_addr_busy);
 592
 593         if (!result && parent)
 594                 result = i2c_check_mux_parents(parent, addr);
 595
 596         return result;
 597 }
 598
 599 /* recurse down mux tree */
 600 static int i2c_check_mux_children(struct device *dev, void *addrp)
 601 {
 602         int result;
 603
 604         if (dev->type == &i2c_adapter_type)
 605                 result = device_for_each_child(dev, addrp,
 606                                                 i2c_check_mux_children);
 607         else
 608                 result = __i2c_check_addr_busy(dev, addrp);
 609
 610         return result;
 611 }
 612
 613 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 614 {
 615         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 616         int result = 0;
 617
 618         if (parent)
 619                 result = i2c_check_mux_parents(parent, addr);
 620
 621         if (!result)
 622                 result = device_for_each_child(&adapter->dev, &addr,
 623                                                 i2c_check_mux_children);
 624
 625         return result;
 626 }
 627
 628 /**
 629  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 630  * @adapter: Target I2C bus segment
 631  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 632  *      locks only this branch in the adapter tree
 633  */
 634 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 635                                  unsigned int flags)
 636 {
 637         rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 638 }
 639
 640 /**
 641  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 642  * @adapter: Target I2C bus segment
 643  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 644  *      trylocks only this branch in the adapter tree
 645  */
 646 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 647                                    unsigned int flags)
 648 {
 649         return rt_mutex_trylock(&adapter->bus_lock);
 650 }
 651
 652 /**
 653  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 654  * @adapter: Target I2C bus segment
 655  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 656  *      unlocks only this branch in the adapter tree
 657  */
 658 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 659                                    unsigned int flags)
 660 {
 661         rt_mutex_unlock(&adapter->bus_lock);
 662 }
 663
 664 static void i2c_dev_set_name(struct i2c_adapter *adap,
 665                              struct i2c_client *client,
 666                              struct i2c_board_info const *info)
 667 {
 668         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 669
 670         if (info && info->dev_name) {
 671                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 672                 return;
 673         }
 674
 675         if (adev) {
 676                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 677                 return;
 678         }
 679
 680         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 681                      i2c_encode_flags_to_addr(client));
 682 }
 683
 684 int i2c_dev_irq_from_resources(const struct resource *resources,
 685                                unsigned int num_resources)
 686 {
 687         struct irq_data *irqd;
 688         int i;
 689
 690         for (i = 0; i < num_resources; i++) {
 691                 const struct resource *r = &resources[i];
 692
 693                 if (resource_type(r) != IORESOURCE_IRQ)
 694                         continue;
 695
 696                 if (r->flags & IORESOURCE_BITS) {
 697                         irqd = irq_get_irq_data(r->start);
 698                         if (!irqd)
 699                                 break;
 700
 701                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 702                 }
 703
 704                 return r->start;
 705         }
 706
 707         return 0;
 708 }
 709
 710 /**
 711  * i2c_new_client_device - instantiate an i2c device
 712  * @adap: the adapter managing the device
 713  * @info: describes one I2C device; bus_num is ignored
 714  * Context: can sleep
 715  *
 716  * Create an i2c device. Binding is handled through driver model
 717  * probe()/remove() methods.  A driver may be bound to this device when we
 718  * return from this function, or any later moment (e.g. maybe hotplugging will
 719  * load the driver module).  This call is not appropriate for use by mainboard
 720  * initialization logic, which usually runs during an arch_initcall() long
 721  * before any i2c_adapter could exist.
 722  *
 723  * This returns the new i2c client, which may be saved for later use with
 724  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 725  */
 726 struct i2c_client *
 727 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 728 {
 729         struct i2c_client       *client;
 730         int                     status;
 731
 732         client = kzalloc(sizeof *client, GFP_KERNEL);
 733         if (!client)
 734                 return ERR_PTR(-ENOMEM);
 735
 736         client->adapter = adap;
 737
 738         client->dev.platform_data = info->platform_data;
 739         client->flags = info->flags;
 740         client->addr = info->addr;
 741
 742         client->init_irq = info->irq;
 743         if (!client->init_irq)
 744                 client->init_irq = i2c_dev_irq_from_resources(info->resources,
 745                                                          info->num_resources);
 746
 747         strlcpy(client->name, info->type, sizeof(client->name));
 748
 749         status = i2c_check_addr_validity(client->addr, client->flags);
 750         if (status) {
 751                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 752                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 753                 goto out_err_silent;
 754         }
 755
 756         /* Check for address business */
 757         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 758         if (status)
 759                 goto out_err;
 760
 761         client->dev.parent = &client->adapter->dev;
 762         client->dev.bus = &i2c_bus_type;
 763         client->dev.type = &i2c_client_type;
 764         client->dev.of_node = of_node_get(info->of_node);
 765         client->dev.fwnode = info->fwnode;
 766
 767         i2c_dev_set_name(adap, client, info);
 768
 769         if (info->properties) {
 770                 status = device_add_properties(&client->dev, info->properties);
 771                 if (status) {
 772                         dev_err(&adap->dev,
 773                                 "Failed to add properties to client %s: %d\n",
 774                                 client->name, status);
 775                         goto out_err_put_of_node;
 776                 }
 777         }
 778
 779         status = device_register(&client->dev);
 780         if (status)
 781                 goto out_free_props;
 782
 783         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 784                 client->name, dev_name(&client->dev));
 785
 786         return client;
 787
 788 out_free_props:
 789         if (info->properties)
 790                 device_remove_properties(&client->dev);
 791 out_err_put_of_node:
 792         of_node_put(info->of_node);
 793 out_err:
 794         dev_err(&adap->dev,
 795                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 796                 client->name, client->addr, status);
 797 out_err_silent:
 798         kfree(client);
 799         return ERR_PTR(status);
 800 }
 801 EXPORT_SYMBOL_GPL(i2c_new_client_device);
 802
 803 /**
 804  * i2c_new_device - instantiate an i2c device
 805  * @adap: the adapter managing the device
 806  * @info: describes one I2C device; bus_num is ignored
 807  * Context: can sleep
 808  *
 809  * This deprecated function has the same functionality as
 810  * @i2c_new_client_device, it just returns NULL instead of an ERR_PTR in case of
 811  * an error for compatibility with current I2C API. It will be removed once all
 812  * users are converted.
 813  *
 814  * This returns the new i2c client, which may be saved for later use with
 815  * i2c_unregister_device(); or NULL to indicate an error.
 816  */
 817 struct i2c_client *
 818 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 819 {
 820         struct i2c_client *ret;
 821
 822         ret = i2c_new_client_device(adap, info);
 823         return IS_ERR(ret) ? NULL : ret;
 824 }
 825 EXPORT_SYMBOL_GPL(i2c_new_device);
 826
 827
 828 /**
 829  * i2c_unregister_device - reverse effect of i2c_new_device()
 830  * @client: value returned from i2c_new_device()
 831  * Context: can sleep
 832  */
 833 void i2c_unregister_device(struct i2c_client *client)
 834 {
 835         if (IS_ERR_OR_NULL(client))
 836                 return;
 837
 838         if (client->dev.of_node) {
 839                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 840                 of_node_put(client->dev.of_node);
 841         }
 842
 843         if (ACPI_COMPANION(&client->dev))
 844                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 845         device_unregister(&client->dev);
 846 }
 847 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 848
 849
 850 static const struct i2c_device_id dummy_id[] = {
 851         { "dummy", 0 },
 852         { },
 853 };
 854
 855 static int dummy_probe(struct i2c_client *client,
 856                        const struct i2c_device_id *id)
 857 {
 858         return 0;
 859 }
 860
 861 static int dummy_remove(struct i2c_client *client)
 862 {
 863         return 0;
 864 }
 865
 866 static struct i2c_driver dummy_driver = {
 867         .driver.name    = "dummy",
 868         .probe          = dummy_probe,
 869         .remove         = dummy_remove,
 870         .id_table       = dummy_id,
 871 };
 872
 873 /**
 874  * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 875  * @adapter: the adapter managing the device
 876  * @address: seven bit address to be used
 877  * Context: can sleep
 878  *
 879  * This returns an I2C client bound to the "dummy" driver, intended for use
 880  * with devices that consume multiple addresses.  Examples of such chips
 881  * include various EEPROMS (like 24c04 and 24c08 models).
 882  *
 883  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 884  * except i2c_transfer() need a client handle; the dummy will be that handle.
 885  * And second, this prevents the specified address from being bound to a
 886  * different driver.
 887  *
 888  * This returns the new i2c client, which should be saved for later use with
 889  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 890  */
 891 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
 892 {
 893         struct i2c_board_info info = {
 894                 I2C_BOARD_INFO("dummy", address),
 895         };
 896
 897         return i2c_new_client_device(adapter, &info);
 898 }
 899 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
 900
 901 /**
 902  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 903  * @adapter: the adapter managing the device
 904  * @address: seven bit address to be used
 905  * Context: can sleep
 906  *
 907  * This deprecated function has the same functionality as @i2c_new_dummy_device,
 908  * it just returns NULL instead of an ERR_PTR in case of an error for
 909  * compatibility with current I2C API. It will be removed once all users are
 910  * converted.
 911  *
 912  * This returns the new i2c client, which should be saved for later use with
 913  * i2c_unregister_device(); or NULL to indicate an error.
 914  */
 915 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 916 {
 917         struct i2c_client *ret;
 918
 919         ret = i2c_new_dummy_device(adapter, address);
 920         return IS_ERR(ret) ? NULL : ret;
 921 }
 922 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 923
 924 struct i2c_dummy_devres {
 925         struct i2c_client *client;
 926 };
 927
 928 static void devm_i2c_release_dummy(struct device *dev, void *res)
 929 {
 930         struct i2c_dummy_devres *this = res;
 931
 932         i2c_unregister_device(this->client);
 933 }
 934
 935 /**
 936  * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 937  * @dev: device the managed resource is bound to
 938  * @adapter: the adapter managing the device
 939  * @address: seven bit address to be used
 940  * Context: can sleep
 941  *
 942  * This is the device-managed version of @i2c_new_dummy_device. It returns the
 943  * new i2c client or an ERR_PTR in case of an error.
 944  */
 945 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
 946                                              struct i2c_adapter *adapter,
 947                                              u16 address)
 948 {
 949         struct i2c_dummy_devres *dr;
 950         struct i2c_client *client;
 951
 952         dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
 953         if (!dr)
 954                 return ERR_PTR(-ENOMEM);
 955
 956         client = i2c_new_dummy_device(adapter, address);
 957         if (IS_ERR(client)) {
 958                 devres_free(dr);
 959         } else {
 960                 dr->client = client;
 961                 devres_add(dev, dr);
 962         }
 963
 964         return client;
 965 }
 966 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
 967
 968 /**
 969  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 970  * and create the associated device
 971  * @client: Handle to the primary client
 972  * @name: Handle to specify which secondary address to get
 973  * @default_addr: Used as a fallback if no secondary address was specified
 974  * Context: can sleep
 975  *
 976  * I2C clients can be composed of multiple I2C slaves bound together in a single
 977  * component. The I2C client driver then binds to the master I2C slave and needs
 978  * to create I2C dummy clients to communicate with all the other slaves.
 979  *
 980  * This function creates and returns an I2C dummy client whose I2C address is
 981  * retrieved from the platform firmware based on the given slave name. If no
 982  * address is specified by the firmware default_addr is used.
 983  *
 984  * On DT-based platforms the address is retrieved from the "reg" property entry
 985  * cell whose "reg-names" value matches the slave name.
 986  *
 987  * This returns the new i2c client, which should be saved for later use with
 988  * i2c_unregister_device(); or NULL to indicate an error.
 989  */
 990 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 991                                                 const char *name,
 992                                                 u16 default_addr)
 993 {
 994         struct device_node *np = client->dev.of_node;
 995         u32 addr = default_addr;
 996         int i;
 997
 998         if (np) {
 999                 i = of_property_match_string(np, "reg-names", name);
1000                 if (i >= 0)
1001                         of_property_read_u32_index(np, "reg", i, &addr);
1002         }
1003
1004         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1005         return i2c_new_dummy(client->adapter, addr);
1006 }
1007 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
1008
1009 /* ------------------------------------------------------------------------- */
1010
1011 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1012
1013 static void i2c_adapter_dev_release(struct device *dev)
1014 {
1015         struct i2c_adapter *adap = to_i2c_adapter(dev);
1016         complete(&adap->dev_released);
1017 }
1018
1019 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1020 {
1021         unsigned int depth = 0;
1022
1023         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1024                 depth++;
1025
1026         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1027                   "adapter depth exceeds lockdep subclass limit\n");
1028
1029         return depth;
1030 }
1031 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1032
1033 /*
1034  * Let users instantiate I2C devices through sysfs. This can be used when
1035  * platform initialization code doesn't contain the proper data for
1036  * whatever reason. Also useful for drivers that do device detection and
1037  * detection fails, either because the device uses an unexpected address,
1038  * or this is a compatible device with different ID register values.
1039  *
1040  * Parameter checking may look overzealous, but we really don't want
1041  * the user to provide incorrect parameters.
1042  */
1043 static ssize_t
1044 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1045                      const char *buf, size_t count)
1046 {
1047         struct i2c_adapter *adap = to_i2c_adapter(dev);
1048         struct i2c_board_info info;
1049         struct i2c_client *client;
1050         char *blank, end;
1051         int res;
1052
1053         memset(&info, 0, sizeof(struct i2c_board_info));
1054
1055         blank = strchr(buf, ' ');
1056         if (!blank) {
1057                 dev_err(dev, "%s: Missing parameters\n", "new_device");
1058                 return -EINVAL;
1059         }
1060         if (blank - buf > I2C_NAME_SIZE - 1) {
1061                 dev_err(dev, "%s: Invalid device name\n", "new_device");
1062                 return -EINVAL;
1063         }
1064         memcpy(info.type, buf, blank - buf);
1065
1066         /* Parse remaining parameters, reject extra parameters */
1067         res = sscanf(++blank, "%hi%c", &info.addr, &end);
1068         if (res < 1) {
1069                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1070                 return -EINVAL;
1071         }
1072         if (res > 1  && end != '\n') {
1073                 dev_err(dev, "%s: Extra parameters\n", "new_device");
1074                 return -EINVAL;
1075         }
1076
1077         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1078                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1079                 info.flags |= I2C_CLIENT_TEN;
1080         }
1081
1082         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1083                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1084                 info.flags |= I2C_CLIENT_SLAVE;
1085         }
1086
1087         client = i2c_new_client_device(adap, &info);
1088         if (IS_ERR(client))
1089                 return PTR_ERR(client);
1090
1091         /* Keep track of the added device */
1092         mutex_lock(&adap->userspace_clients_lock);
1093         list_add_tail(&client->detected, &adap->userspace_clients);
1094         mutex_unlock(&adap->userspace_clients_lock);
1095         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1096                  info.type, info.addr);
1097
1098         return count;
1099 }
1100 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1101
1102 /*
1103  * And of course let the users delete the devices they instantiated, if
1104  * they got it wrong. This interface can only be used to delete devices
1105  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1106  * don't delete devices to which some kernel code still has references.
1107  *
1108  * Parameter checking may look overzealous, but we really don't want
1109  * the user to delete the wrong device.
1110  */
1111 static ssize_t
1112 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1113                         const char *buf, size_t count)
1114 {
1115         struct i2c_adapter *adap = to_i2c_adapter(dev);
1116         struct i2c_client *client, *next;
1117         unsigned short addr;
1118         char end;
1119         int res;
1120
1121         /* Parse parameters, reject extra parameters */
1122         res = sscanf(buf, "%hi%c", &addr, &end);
1123         if (res < 1) {
1124                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1125                 return -EINVAL;
1126         }
1127         if (res > 1  && end != '\n') {
1128                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1129                 return -EINVAL;
1130         }
1131
1132         /* Make sure the device was added through sysfs */
1133         res = -ENOENT;
1134         mutex_lock_nested(&adap->userspace_clients_lock,
1135                           i2c_adapter_depth(adap));
1136         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1137                                  detected) {
1138                 if (i2c_encode_flags_to_addr(client) == addr) {
1139                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1140                                  "delete_device", client->name, client->addr);
1141
1142                         list_del(&client->detected);
1143                         i2c_unregister_device(client);
1144                         res = count;
1145                         break;
1146                 }
1147         }
1148         mutex_unlock(&adap->userspace_clients_lock);
1149
1150         if (res < 0)
1151                 dev_err(dev, "%s: Can't find device in list\n",
1152                         "delete_device");
1153         return res;
1154 }
1155 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1156                                    i2c_sysfs_delete_device);
1157
1158 static struct attribute *i2c_adapter_attrs[] = {
1159         &dev_attr_name.attr,
1160         &dev_attr_new_device.attr,
1161         &dev_attr_delete_device.attr,
1162         NULL
1163 };
1164 ATTRIBUTE_GROUPS(i2c_adapter);
1165
1166 struct device_type i2c_adapter_type = {
1167         .groups         = i2c_adapter_groups,
1168         .release        = i2c_adapter_dev_release,
1169 };
1170 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1171
1172 /**
1173  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1174  * @dev: device, probably from some driver model iterator
1175  *
1176  * When traversing the driver model tree, perhaps using driver model
1177  * iterators like @device_for_each_child(), you can't assume very much
1178  * about the nodes you find.  Use this function to avoid oopses caused
1179  * by wrongly treating some non-I2C device as an i2c_adapter.
1180  */
1181 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1182 {
1183         return (dev->type == &i2c_adapter_type)
1184                         ? to_i2c_adapter(dev)
1185                         : NULL;
1186 }
1187 EXPORT_SYMBOL(i2c_verify_adapter);
1188
1189 #ifdef CONFIG_I2C_COMPAT
1190 static struct class_compat *i2c_adapter_compat_class;
1191 #endif
1192
1193 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1194 {
1195         struct i2c_devinfo      *devinfo;
1196
1197         down_read(&__i2c_board_lock);
1198         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1199                 if (devinfo->busnum == adapter->nr
1200                                 && !i2c_new_device(adapter,
1201                                                 &devinfo->board_info))
1202                         dev_err(&adapter->dev,
1203                                 "Can't create device at 0x%02x\n",
1204                                 devinfo->board_info.addr);
1205         }
1206         up_read(&__i2c_board_lock);
1207 }
1208
1209 static int i2c_do_add_adapter(struct i2c_driver *driver,
1210                               struct i2c_adapter *adap)
1211 {
1212         /* Detect supported devices on that bus, and instantiate them */
1213         i2c_detect(adap, driver);
1214
1215         return 0;
1216 }
1217
1218 static int __process_new_adapter(struct device_driver *d, void *data)
1219 {
1220         return i2c_do_add_adapter(to_i2c_driver(d), data);
1221 }
1222
1223 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1224         .lock_bus =    i2c_adapter_lock_bus,
1225         .trylock_bus = i2c_adapter_trylock_bus,
1226         .unlock_bus =  i2c_adapter_unlock_bus,
1227 };
1228
1229 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1230 {
1231         struct irq_domain *domain = adap->host_notify_domain;
1232         irq_hw_number_t hwirq;
1233
1234         if (!domain)
1235                 return;
1236
1237         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1238                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1239
1240         irq_domain_remove(domain);
1241         adap->host_notify_domain = NULL;
1242 }
1243
1244 static int i2c_host_notify_irq_map(struct irq_domain *h,
1245                                           unsigned int virq,
1246                                           irq_hw_number_t hw_irq_num)
1247 {
1248         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1249
1250         return 0;
1251 }
1252
1253 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1254         .map = i2c_host_notify_irq_map,
1255 };
1256
1257 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1258 {
1259         struct irq_domain *domain;
1260
1261         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1262                 return 0;
1263
1264         domain = irq_domain_create_linear(adap->dev.fwnode,
1265                                           I2C_ADDR_7BITS_COUNT,
1266                                           &i2c_host_notify_irq_ops, adap);
1267         if (!domain)
1268                 return -ENOMEM;
1269
1270         adap->host_notify_domain = domain;
1271
1272         return 0;
1273 }
1274
1275 /**
1276  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1277  * I2C client.
1278  * @adap: the adapter
1279  * @addr: the I2C address of the notifying device
1280  * Context: can't sleep
1281  *
1282  * Helper function to be called from an I2C bus driver's interrupt
1283  * handler. It will schedule the Host Notify IRQ.
1284  */
1285 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1286 {
1287         int irq;
1288
1289         if (!adap)
1290                 return -EINVAL;
1291
1292         irq = irq_find_mapping(adap->host_notify_domain, addr);
1293         if (irq <= 0)
1294                 return -ENXIO;
1295
1296         generic_handle_irq(irq);
1297
1298         return 0;
1299 }
1300 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1301
1302 static int i2c_register_adapter(struct i2c_adapter *adap)
1303 {
1304         int res = -EINVAL;
1305
1306         /* Can't register until after driver model init */
1307         if (WARN_ON(!is_registered)) {
1308                 res = -EAGAIN;
1309                 goto out_list;
1310         }
1311
1312         /* Sanity checks */
1313         if (WARN(!adap->name[0], "i2c adapter has no name"))
1314                 goto out_list;
1315
1316         if (!adap->algo) {
1317                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1318                 goto out_list;
1319         }
1320
1321         if (!adap->lock_ops)
1322                 adap->lock_ops = &i2c_adapter_lock_ops;
1323
1324         adap->locked_flags = 0;
1325         rt_mutex_init(&adap->bus_lock);
1326         rt_mutex_init(&adap->mux_lock);
1327         mutex_init(&adap->userspace_clients_lock);
1328         INIT_LIST_HEAD(&adap->userspace_clients);
1329
1330         /* Set default timeout to 1 second if not already set */
1331         if (adap->timeout == 0)
1332                 adap->timeout = HZ;
1333
1334         /* register soft irqs for Host Notify */
1335         res = i2c_setup_host_notify_irq_domain(adap);
1336         if (res) {
1337                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1338                        adap->name, res);
1339                 goto out_list;
1340         }
1341
1342         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1343         adap->dev.bus = &i2c_bus_type;
1344         adap->dev.type = &i2c_adapter_type;
1345         res = device_register(&adap->dev);
1346         if (res) {
1347                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1348                 goto out_list;
1349         }
1350
1351         res = of_i2c_setup_smbus_alert(adap);
1352         if (res)
1353                 goto out_reg;
1354
1355         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1356
1357         pm_runtime_no_callbacks(&adap->dev);
1358         pm_suspend_ignore_children(&adap->dev, true);
1359         pm_runtime_enable(&adap->dev);
1360
1361 #ifdef CONFIG_I2C_COMPAT
1362         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1363                                        adap->dev.parent);
1364         if (res)
1365                 dev_warn(&adap->dev,
1366                          "Failed to create compatibility class link\n");
1367 #endif
1368
1369         i2c_init_recovery(adap);
1370
1371         /* create pre-declared device nodes */
1372         of_i2c_register_devices(adap);
1373         i2c_acpi_register_devices(adap);
1374         i2c_acpi_install_space_handler(adap);
1375
1376         if (adap->nr < __i2c_first_dynamic_bus_num)
1377                 i2c_scan_static_board_info(adap);
1378
1379         /* Notify drivers */
1380         mutex_lock(&core_lock);
1381         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1382         mutex_unlock(&core_lock);
1383
1384         return 0;
1385
1386 out_reg:
1387         init_completion(&adap->dev_released);
1388         device_unregister(&adap->dev);
1389         wait_for_completion(&adap->dev_released);
1390 out_list:
1391         mutex_lock(&core_lock);
1392         idr_remove(&i2c_adapter_idr, adap->nr);
1393         mutex_unlock(&core_lock);
1394         return res;
1395 }
1396
1397 /**
1398  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1399  * @adap: the adapter to register (with adap->nr initialized)
1400  * Context: can sleep
1401  *
1402  * See i2c_add_numbered_adapter() for details.
1403  */
1404 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1405 {
1406         int id;
1407
1408         mutex_lock(&core_lock);
1409         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1410         mutex_unlock(&core_lock);
1411         if (WARN(id < 0, "couldn't get idr"))
1412                 return id == -ENOSPC ? -EBUSY : id;
1413
1414         return i2c_register_adapter(adap);
1415 }
1416
1417 /**
1418  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1419  * @adapter: the adapter to add
1420  * Context: can sleep
1421  *
1422  * This routine is used to declare an I2C adapter when its bus number
1423  * doesn't matter or when its bus number is specified by an dt alias.
1424  * Examples of bases when the bus number doesn't matter: I2C adapters
1425  * dynamically added by USB links or PCI plugin cards.
1426  *
1427  * When this returns zero, a new bus number was allocated and stored
1428  * in adap->nr, and the specified adapter became available for clients.
1429  * Otherwise, a negative errno value is returned.
1430  */
1431 int i2c_add_adapter(struct i2c_adapter *adapter)
1432 {
1433         struct device *dev = &adapter->dev;
1434         int id;
1435
1436         if (dev->of_node) {
1437                 id = of_alias_get_id(dev->of_node, "i2c");
1438                 if (id >= 0) {
1439                         adapter->nr = id;
1440                         return __i2c_add_numbered_adapter(adapter);
1441                 }
1442         }
1443
1444         mutex_lock(&core_lock);
1445         id = idr_alloc(&i2c_adapter_idr, adapter,
1446                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1447         mutex_unlock(&core_lock);
1448         if (WARN(id < 0, "couldn't get idr"))
1449                 return id;
1450
1451         adapter->nr = id;
1452
1453         return i2c_register_adapter(adapter);
1454 }
1455 EXPORT_SYMBOL(i2c_add_adapter);
1456
1457 /**
1458  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1459  * @adap: the adapter to register (with adap->nr initialized)
1460  * Context: can sleep
1461  *
1462  * This routine is used to declare an I2C adapter when its bus number
1463  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1464  * or otherwise built in to the system's mainboard, and where i2c_board_info
1465  * is used to properly configure I2C devices.
1466  *
1467  * If the requested bus number is set to -1, then this function will behave
1468  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1469  *
1470  * If no devices have pre-been declared for this bus, then be sure to
1471  * register the adapter before any dynamically allocated ones.  Otherwise
1472  * the required bus ID may not be available.
1473  *
1474  * When this returns zero, the specified adapter became available for
1475  * clients using the bus number provided in adap->nr.  Also, the table
1476  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1477  * and the appropriate driver model device nodes are created.  Otherwise, a
1478  * negative errno value is returned.
1479  */
1480 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1481 {
1482         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1483                 return i2c_add_adapter(adap);
1484
1485         return __i2c_add_numbered_adapter(adap);
1486 }
1487 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1488
1489 static void i2c_do_del_adapter(struct i2c_driver *driver,
1490                               struct i2c_adapter *adapter)
1491 {
1492         struct i2c_client *client, *_n;
1493
1494         /* Remove the devices we created ourselves as the result of hardware
1495          * probing (using a driver's detect method) */
1496         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1497                 if (client->adapter == adapter) {
1498                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1499                                 client->name, client->addr);
1500                         list_del(&client->detected);
1501                         i2c_unregister_device(client);
1502                 }
1503         }
1504 }
1505
1506 static int __unregister_client(struct device *dev, void *dummy)
1507 {
1508         struct i2c_client *client = i2c_verify_client(dev);
1509         if (client && strcmp(client->name, "dummy"))
1510                 i2c_unregister_device(client);
1511         return 0;
1512 }
1513
1514 static int __unregister_dummy(struct device *dev, void *dummy)
1515 {
1516         struct i2c_client *client = i2c_verify_client(dev);
1517         i2c_unregister_device(client);
1518         return 0;
1519 }
1520
1521 static int __process_removed_adapter(struct device_driver *d, void *data)
1522 {
1523         i2c_do_del_adapter(to_i2c_driver(d), data);
1524         return 0;
1525 }
1526
1527 /**
1528  * i2c_del_adapter - unregister I2C adapter
1529  * @adap: the adapter being unregistered
1530  * Context: can sleep
1531  *
1532  * This unregisters an I2C adapter which was previously registered
1533  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1534  */
1535 void i2c_del_adapter(struct i2c_adapter *adap)
1536 {
1537         struct i2c_adapter *found;
1538         struct i2c_client *client, *next;
1539
1540         /* First make sure that this adapter was ever added */
1541         mutex_lock(&core_lock);
1542         found = idr_find(&i2c_adapter_idr, adap->nr);
1543         mutex_unlock(&core_lock);
1544         if (found != adap) {
1545                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1546                 return;
1547         }
1548
1549         i2c_acpi_remove_space_handler(adap);
1550         /* Tell drivers about this removal */
1551         mutex_lock(&core_lock);
1552         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1553                                __process_removed_adapter);
1554         mutex_unlock(&core_lock);
1555
1556         /* Remove devices instantiated from sysfs */
1557         mutex_lock_nested(&adap->userspace_clients_lock,
1558                           i2c_adapter_depth(adap));
1559         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1560                                  detected) {
1561                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1562                         client->addr);
1563                 list_del(&client->detected);
1564                 i2c_unregister_device(client);
1565         }
1566         mutex_unlock(&adap->userspace_clients_lock);
1567
1568         /* Detach any active clients. This can't fail, thus we do not
1569          * check the returned value. This is a two-pass process, because
1570          * we can't remove the dummy devices during the first pass: they
1571          * could have been instantiated by real devices wishing to clean
1572          * them up properly, so we give them a chance to do that first. */
1573         device_for_each_child(&adap->dev, NULL, __unregister_client);
1574         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1575
1576 #ifdef CONFIG_I2C_COMPAT
1577         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1578                                  adap->dev.parent);
1579 #endif
1580
1581         /* device name is gone after device_unregister */
1582         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1583
1584         pm_runtime_disable(&adap->dev);
1585
1586         i2c_host_notify_irq_teardown(adap);
1587
1588         /* wait until all references to the device are gone
1589          *
1590          * FIXME: This is old code and should ideally be replaced by an
1591          * alternative which results in decoupling the lifetime of the struct
1592          * device from the i2c_adapter, like spi or netdev do. Any solution
1593          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1594          */
1595         init_completion(&adap->dev_released);
1596         device_unregister(&adap->dev);
1597         wait_for_completion(&adap->dev_released);
1598
1599         /* free bus id */
1600         mutex_lock(&core_lock);
1601         idr_remove(&i2c_adapter_idr, adap->nr);
1602         mutex_unlock(&core_lock);
1603
1604         /* Clear the device structure in case this adapter is ever going to be
1605            added again */
1606         memset(&adap->dev, 0, sizeof(adap->dev));
1607 }
1608 EXPORT_SYMBOL(i2c_del_adapter);
1609
1610 /**
1611  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1612  * @dev: The device to scan for I2C timing properties
1613  * @t: the i2c_timings struct to be filled with values
1614  * @use_defaults: bool to use sane defaults derived from the I2C specification
1615  *                when properties are not found, otherwise use 0
1616  *
1617  * Scan the device for the generic I2C properties describing timing parameters
1618  * for the signal and fill the given struct with the results. If a property was
1619  * not found and use_defaults was true, then maximum timings are assumed which
1620  * are derived from the I2C specification. If use_defaults is not used, the
1621  * results will be 0, so drivers can apply their own defaults later. The latter
1622  * is mainly intended for avoiding regressions of existing drivers which want
1623  * to switch to this function. New drivers almost always should use the defaults.
1624  */
1625
1626 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1627 {
1628         int ret;
1629
1630         memset(t, 0, sizeof(*t));
1631
1632         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1633         if (ret && use_defaults)
1634                 t->bus_freq_hz = 100000;
1635
1636         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1637         if (ret && use_defaults) {
1638                 if (t->bus_freq_hz <= 100000)
1639                         t->scl_rise_ns = 1000;
1640                 else if (t->bus_freq_hz <= 400000)
1641                         t->scl_rise_ns = 300;
1642                 else
1643                         t->scl_rise_ns = 120;
1644         }
1645
1646         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1647         if (ret && use_defaults) {
1648                 if (t->bus_freq_hz <= 400000)
1649                         t->scl_fall_ns = 300;
1650                 else
1651                         t->scl_fall_ns = 120;
1652         }
1653
1654         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1655
1656         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1657         if (ret && use_defaults)
1658                 t->sda_fall_ns = t->scl_fall_ns;
1659
1660         device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1661 }
1662 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1663
1664 /* ------------------------------------------------------------------------- */
1665
1666 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1667 {
1668         int res;
1669
1670         mutex_lock(&core_lock);
1671         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1672         mutex_unlock(&core_lock);
1673
1674         return res;
1675 }
1676 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1677
1678 static int __process_new_driver(struct device *dev, void *data)
1679 {
1680         if (dev->type != &i2c_adapter_type)
1681                 return 0;
1682         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1683 }
1684
1685 /*
1686  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1687  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1688  */
1689
1690 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1691 {
1692         int res;
1693
1694         /* Can't register until after driver model init */
1695         if (WARN_ON(!is_registered))
1696                 return -EAGAIN;
1697
1698         /* add the driver to the list of i2c drivers in the driver core */
1699         driver->driver.owner = owner;
1700         driver->driver.bus = &i2c_bus_type;
1701         INIT_LIST_HEAD(&driver->clients);
1702
1703         /* When registration returns, the driver core
1704          * will have called probe() for all matching-but-unbound devices.
1705          */
1706         res = driver_register(&driver->driver);
1707         if (res)
1708                 return res;
1709
1710         pr_debug("driver [%s] registered\n", driver->driver.name);
1711
1712         /* Walk the adapters that are already present */
1713         i2c_for_each_dev(driver, __process_new_driver);
1714
1715         return 0;
1716 }
1717 EXPORT_SYMBOL(i2c_register_driver);
1718
1719 static int __process_removed_driver(struct device *dev, void *data)
1720 {
1721         if (dev->type == &i2c_adapter_type)
1722                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1723         return 0;
1724 }
1725
1726 /**
1727  * i2c_del_driver - unregister I2C driver
1728  * @driver: the driver being unregistered
1729  * Context: can sleep
1730  */
1731 void i2c_del_driver(struct i2c_driver *driver)
1732 {
1733         i2c_for_each_dev(driver, __process_removed_driver);
1734
1735         driver_unregister(&driver->driver);
1736         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1737 }
1738 EXPORT_SYMBOL(i2c_del_driver);
1739
1740 /* ------------------------------------------------------------------------- */
1741
1742 /**
1743  * i2c_use_client - increments the reference count of the i2c client structure
1744  * @client: the client being referenced
1745  *
1746  * Each live reference to a client should be refcounted. The driver model does
1747  * that automatically as part of driver binding, so that most drivers don't
1748  * need to do this explicitly: they hold a reference until they're unbound
1749  * from the device.
1750  *
1751  * A pointer to the client with the incremented reference counter is returned.
1752  */
1753 struct i2c_client *i2c_use_client(struct i2c_client *client)
1754 {
1755         if (client && get_device(&client->dev))
1756                 return client;
1757         return NULL;
1758 }
1759 EXPORT_SYMBOL(i2c_use_client);
1760
1761 /**
1762  * i2c_release_client - release a use of the i2c client structure
1763  * @client: the client being no longer referenced
1764  *
1765  * Must be called when a user of a client is finished with it.
1766  */
1767 void i2c_release_client(struct i2c_client *client)
1768 {
1769         if (client)
1770                 put_device(&client->dev);
1771 }
1772 EXPORT_SYMBOL(i2c_release_client);
1773
1774 struct i2c_cmd_arg {
1775         unsigned        cmd;
1776         void            *arg;
1777 };
1778
1779 static int i2c_cmd(struct device *dev, void *_arg)
1780 {
1781         struct i2c_client       *client = i2c_verify_client(dev);
1782         struct i2c_cmd_arg      *arg = _arg;
1783         struct i2c_driver       *driver;
1784
1785         if (!client || !client->dev.driver)
1786                 return 0;
1787
1788         driver = to_i2c_driver(client->dev.driver);
1789         if (driver->command)
1790                 driver->command(client, arg->cmd, arg->arg);
1791         return 0;
1792 }
1793
1794 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1795 {
1796         struct i2c_cmd_arg      cmd_arg;
1797
1798         cmd_arg.cmd = cmd;
1799         cmd_arg.arg = arg;
1800         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1801 }
1802 EXPORT_SYMBOL(i2c_clients_command);
1803
1804 static int __init i2c_init(void)
1805 {
1806         int retval;
1807
1808         retval = of_alias_get_highest_id("i2c");
1809
1810         down_write(&__i2c_board_lock);
1811         if (retval >= __i2c_first_dynamic_bus_num)
1812                 __i2c_first_dynamic_bus_num = retval + 1;
1813         up_write(&__i2c_board_lock);
1814
1815         retval = bus_register(&i2c_bus_type);
1816         if (retval)
1817                 return retval;
1818
1819         is_registered = true;
1820
1821 #ifdef CONFIG_I2C_COMPAT
1822         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1823         if (!i2c_adapter_compat_class) {
1824                 retval = -ENOMEM;
1825                 goto bus_err;
1826         }
1827 #endif
1828         retval = i2c_add_driver(&dummy_driver);
1829         if (retval)
1830                 goto class_err;
1831
1832         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1833                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1834         if (IS_ENABLED(CONFIG_ACPI))
1835                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1836
1837         return 0;
1838
1839 class_err:
1840 #ifdef CONFIG_I2C_COMPAT
1841         class_compat_unregister(i2c_adapter_compat_class);
1842 bus_err:
1843 #endif
1844         is_registered = false;
1845         bus_unregister(&i2c_bus_type);
1846         return retval;
1847 }
1848
1849 static void __exit i2c_exit(void)
1850 {
1851         if (IS_ENABLED(CONFIG_ACPI))
1852                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1853         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1854                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1855         i2c_del_driver(&dummy_driver);
1856 #ifdef CONFIG_I2C_COMPAT
1857         class_compat_unregister(i2c_adapter_compat_class);
1858 #endif
1859         bus_unregister(&i2c_bus_type);
1860         tracepoint_synchronize_unregister();
1861 }
1862
1863 /* We must initialize early, because some subsystems register i2c drivers
1864  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1865  */
1866 postcore_initcall(i2c_init);
1867 module_exit(i2c_exit);
1868
1869 /* ----------------------------------------------------
1870  * the functional interface to the i2c busses.
1871  * ----------------------------------------------------
1872  */
1873
1874 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1875 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1876
1877 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1878 {
1879         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1880                             err_msg, msg->addr, msg->len,
1881                             msg->flags & I2C_M_RD ? "read" : "write");
1882         return -EOPNOTSUPP;
1883 }
1884
1885 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1886 {
1887         const struct i2c_adapter_quirks *q = adap->quirks;
1888         int max_num = q->max_num_msgs, i;
1889         bool do_len_check = true;
1890
1891         if (q->flags & I2C_AQ_COMB) {
1892                 max_num = 2;
1893
1894                 /* special checks for combined messages */
1895                 if (num == 2) {
1896                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1897                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1898
1899                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1900                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1901
1902                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1903                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1904
1905                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1906                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1907
1908                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1909                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1910
1911                         do_len_check = false;
1912                 }
1913         }
1914
1915         if (i2c_quirk_exceeded(num, max_num))
1916                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1917
1918         for (i = 0; i < num; i++) {
1919                 u16 len = msgs[i].len;
1920
1921                 if (msgs[i].flags & I2C_M_RD) {
1922                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1923                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1924
1925                         if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1926                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1927                 } else {
1928                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1929                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1930
1931                         if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1932                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1933                 }
1934         }
1935
1936         return 0;
1937 }
1938
1939 /**
1940  * __i2c_transfer - unlocked flavor of i2c_transfer
1941  * @adap: Handle to I2C bus
1942  * @msgs: One or more messages to execute before STOP is issued to
1943  *      terminate the operation; each message begins with a START.
1944  * @num: Number of messages to be executed.
1945  *
1946  * Returns negative errno, else the number of messages executed.
1947  *
1948  * Adapter lock must be held when calling this function. No debug logging
1949  * takes place. adap->algo->master_xfer existence isn't checked.
1950  */
1951 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1952 {
1953         unsigned long orig_jiffies;
1954         int ret, try;
1955
1956         if (WARN_ON(!msgs || num < 1))
1957                 return -EINVAL;
1958
1959         ret = __i2c_check_suspended(adap);
1960         if (ret)
1961                 return ret;
1962
1963         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1964                 return -EOPNOTSUPP;
1965
1966         /*
1967          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1968          * enabled.  This is an efficient way of keeping the for-loop from
1969          * being executed when not needed.
1970          */
1971         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1972                 int i;
1973                 for (i = 0; i < num; i++)
1974                         if (msgs[i].flags & I2C_M_RD)
1975                                 trace_i2c_read(adap, &msgs[i], i);
1976                         else
1977                                 trace_i2c_write(adap, &msgs[i], i);
1978         }
1979
1980         /* Retry automatically on arbitration loss */
1981         orig_jiffies = jiffies;
1982         for (ret = 0, try = 0; try <= adap->retries; try++) {
1983                 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1984                         ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1985                 else
1986                         ret = adap->algo->master_xfer(adap, msgs, num);
1987
1988                 if (ret != -EAGAIN)
1989                         break;
1990                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1991                         break;
1992         }
1993
1994         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1995                 int i;
1996                 for (i = 0; i < ret; i++)
1997                         if (msgs[i].flags & I2C_M_RD)
1998                                 trace_i2c_reply(adap, &msgs[i], i);
1999                 trace_i2c_result(adap, num, ret);
2000         }
2001
2002         return ret;
2003 }
2004 EXPORT_SYMBOL(__i2c_transfer);
2005
2006 /**
2007  * i2c_transfer - execute a single or combined I2C message
2008  * @adap: Handle to I2C bus
2009  * @msgs: One or more messages to execute before STOP is issued to
2010  *      terminate the operation; each message begins with a START.
2011  * @num: Number of messages to be executed.
2012  *
2013  * Returns negative errno, else the number of messages executed.
2014  *
2015  * Note that there is no requirement that each message be sent to
2016  * the same slave address, although that is the most common model.
2017  */
2018 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2019 {
2020         int ret;
2021
2022         if (!adap->algo->master_xfer) {
2023                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2024                 return -EOPNOTSUPP;
2025         }
2026
2027         /* REVISIT the fault reporting model here is weak:
2028          *
2029          *  - When we get an error after receiving N bytes from a slave,
2030          *    there is no way to report "N".
2031          *
2032          *  - When we get a NAK after transmitting N bytes to a slave,
2033          *    there is no way to report "N" ... or to let the master
2034          *    continue executing the rest of this combined message, if
2035          *    that's the appropriate response.
2036          *
2037          *  - When for example "num" is two and we successfully complete
2038          *    the first message but get an error part way through the
2039          *    second, it's unclear whether that should be reported as
2040          *    one (discarding status on the second message) or errno
2041          *    (discarding status on the first one).
2042          */
2043         ret = __i2c_lock_bus_helper(adap);
2044         if (ret)
2045                 return ret;
2046
2047         ret = __i2c_transfer(adap, msgs, num);
2048         i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2049
2050         return ret;
2051 }
2052 EXPORT_SYMBOL(i2c_transfer);
2053
2054 /**
2055  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2056  *                             to/from a buffer
2057  * @client: Handle to slave device
2058  * @buf: Where the data is stored
2059  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2060  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2061  *
2062  * Returns negative errno, or else the number of bytes transferred.
2063  */
2064 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2065                               int count, u16 flags)
2066 {
2067         int ret;
2068         struct i2c_msg msg = {
2069                 .addr = client->addr,
2070                 .flags = flags | (client->flags & I2C_M_TEN),
2071                 .len = count,
2072                 .buf = buf,
2073         };
2074
2075         ret = i2c_transfer(client->adapter, &msg, 1);
2076
2077         /*
2078          * If everything went ok (i.e. 1 msg transferred), return #bytes
2079          * transferred, else error code.
2080          */
2081         return (ret == 1) ? count : ret;
2082 }
2083 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2084
2085 /**
2086  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2087  * @client: The device to query
2088  * @id: The queried information
2089  *
2090  * Returns negative errno on error, zero on success.
2091  */
2092 int i2c_get_device_id(const struct i2c_client *client,
2093                       struct i2c_device_identity *id)
2094 {
2095         struct i2c_adapter *adap = client->adapter;
2096         union i2c_smbus_data raw_id;
2097         int ret;
2098
2099         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2100                 return -EOPNOTSUPP;
2101
2102         raw_id.block[0] = 3;
2103         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2104                              I2C_SMBUS_READ, client->addr << 1,
2105                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2106         if (ret)
2107                 return ret;
2108
2109         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2110         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2111         id->die_revision = raw_id.block[3] & 0x7;
2112         return 0;
2113 }
2114 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2115
2116 /* ----------------------------------------------------
2117  * the i2c address scanning function
2118  * Will not work for 10-bit addresses!
2119  * ----------------------------------------------------
2120  */
2121
2122 /*
2123  * Legacy default probe function, mostly relevant for SMBus. The default
2124  * probe method is a quick write, but it is known to corrupt the 24RF08
2125  * EEPROMs due to a state machine bug, and could also irreversibly
2126  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2127  * we use a short byte read instead. Also, some bus drivers don't implement
2128  * quick write, so we fallback to a byte read in that case too.
2129  * On x86, there is another special case for FSC hardware monitoring chips,
2130  * which want regular byte reads (address 0x73.) Fortunately, these are the
2131  * only known chips using this I2C address on PC hardware.
2132  * Returns 1 if probe succeeded, 0 if not.
2133  */
2134 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2135 {
2136         int err;
2137         union i2c_smbus_data dummy;
2138
2139 #ifdef CONFIG_X86
2140         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2141          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2142                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2143                                      I2C_SMBUS_BYTE_DATA, &dummy);
2144         else
2145 #endif
2146         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2147          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2148                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2149                                      I2C_SMBUS_QUICK, NULL);
2150         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2151                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2152                                      I2C_SMBUS_BYTE, &dummy);
2153         else {
2154                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2155                          addr);
2156                 err = -EOPNOTSUPP;
2157         }
2158
2159         return err >= 0;
2160 }
2161
2162 static int i2c_detect_address(struct i2c_client *temp_client,
2163                               struct i2c_driver *driver)
2164 {
2165         struct i2c_board_info info;
2166         struct i2c_adapter *adapter = temp_client->adapter;
2167         int addr = temp_client->addr;
2168         int err;
2169
2170         /* Make sure the address is valid */
2171         err = i2c_check_7bit_addr_validity_strict(addr);
2172         if (err) {
2173                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2174                          addr);
2175                 return err;
2176         }
2177
2178         /* Skip if already in use (7 bit, no need to encode flags) */
2179         if (i2c_check_addr_busy(adapter, addr))
2180                 return 0;
2181
2182         /* Make sure there is something at this address */
2183         if (!i2c_default_probe(adapter, addr))
2184                 return 0;
2185
2186         /* Finally call the custom detection function */
2187         memset(&info, 0, sizeof(struct i2c_board_info));
2188         info.addr = addr;
2189         err = driver->detect(temp_client, &info);
2190         if (err) {
2191                 /* -ENODEV is returned if the detection fails. We catch it
2192                    here as this isn't an error. */
2193                 return err == -ENODEV ? 0 : err;
2194         }
2195
2196         /* Consistency check */
2197         if (info.type[0] == '\0') {
2198                 dev_err(&adapter->dev,
2199                         "%s detection function provided no name for 0x%x\n",
2200                         driver->driver.name, addr);
2201         } else {
2202                 struct i2c_client *client;
2203
2204                 /* Detection succeeded, instantiate the device */
2205                 if (adapter->class & I2C_CLASS_DEPRECATED)
2206                         dev_warn(&adapter->dev,
2207                                 "This adapter will soon drop class based instantiation of devices. "
2208                                 "Please make sure client 0x%02x gets instantiated by other means. "
2209                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2210                                 info.addr);
2211
2212                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2213                         info.type, info.addr);
2214                 client = i2c_new_device(adapter, &info);
2215                 if (client)
2216                         list_add_tail(&client->detected, &driver->clients);
2217                 else
2218                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2219                                 info.type, info.addr);
2220         }
2221         return 0;
2222 }
2223
2224 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2225 {
2226         const unsigned short *address_list;
2227         struct i2c_client *temp_client;
2228         int i, err = 0;
2229         int adap_id = i2c_adapter_id(adapter);
2230
2231         address_list = driver->address_list;
2232         if (!driver->detect || !address_list)
2233                 return 0;
2234
2235         /* Warn that the adapter lost class based instantiation */
2236         if (adapter->class == I2C_CLASS_DEPRECATED) {
2237                 dev_dbg(&adapter->dev,
2238                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2239                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2240                         driver->driver.name);
2241                 return 0;
2242         }
2243
2244         /* Stop here if the classes do not match */
2245         if (!(adapter->class & driver->class))
2246                 return 0;
2247
2248         /* Set up a temporary client to help detect callback */
2249         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2250         if (!temp_client)
2251                 return -ENOMEM;
2252         temp_client->adapter = adapter;
2253
2254         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2255                 dev_dbg(&adapter->dev,
2256                         "found normal entry for adapter %d, addr 0x%02x\n",
2257                         adap_id, address_list[i]);
2258                 temp_client->addr = address_list[i];
2259                 err = i2c_detect_address(temp_client, driver);
2260                 if (unlikely(err))
2261                         break;
2262         }
2263
2264         kfree(temp_client);
2265         return err;
2266 }
2267
2268 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2269 {
2270         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2271                               I2C_SMBUS_QUICK, NULL) >= 0;
2272 }
2273 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2274
2275 struct i2c_client *
2276 i2c_new_probed_device(struct i2c_adapter *adap,
2277                       struct i2c_board_info *info,
2278                       unsigned short const *addr_list,
2279                       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2280 {
2281         int i;
2282
2283         if (!probe)
2284                 probe = i2c_default_probe;
2285
2286         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2287                 /* Check address validity */
2288                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2289                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2290                                  addr_list[i]);
2291                         continue;
2292                 }
2293
2294                 /* Check address availability (7 bit, no need to encode flags) */
2295                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2296                         dev_dbg(&adap->dev,
2297                                 "Address 0x%02x already in use, not probing\n",
2298                                 addr_list[i]);
2299                         continue;
2300                 }
2301
2302                 /* Test address responsiveness */
2303                 if (probe(adap, addr_list[i]))
2304                         break;
2305         }
2306
2307         if (addr_list[i] == I2C_CLIENT_END) {
2308                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2309                 return NULL;
2310         }
2311
2312         info->addr = addr_list[i];
2313         return i2c_new_device(adap, info);
2314 }
2315 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2316
2317 struct i2c_adapter *i2c_get_adapter(int nr)
2318 {
2319         struct i2c_adapter *adapter;
2320
2321         mutex_lock(&core_lock);
2322         adapter = idr_find(&i2c_adapter_idr, nr);
2323         if (!adapter)
2324                 goto exit;
2325
2326         if (try_module_get(adapter->owner))
2327                 get_device(&adapter->dev);
2328         else
2329                 adapter = NULL;
2330
2331  exit:
2332         mutex_unlock(&core_lock);
2333         return adapter;
2334 }
2335 EXPORT_SYMBOL(i2c_get_adapter);
2336
2337 void i2c_put_adapter(struct i2c_adapter *adap)
2338 {
2339         if (!adap)
2340                 return;
2341
2342         put_device(&adap->dev);
2343         module_put(adap->owner);
2344 }
2345 EXPORT_SYMBOL(i2c_put_adapter);
2346
2347 /**
2348  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2349  * @msg: the message to be checked
2350  * @threshold: the minimum number of bytes for which using DMA makes sense.
2351  *             Should at least be 1.
2352  *
2353  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2354  *         Or a valid pointer to be used with DMA. After use, release it by
2355  *         calling i2c_put_dma_safe_msg_buf().
2356  *
2357  * This function must only be called from process context!
2358  */
2359 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2360 {
2361         /* also skip 0-length msgs for bogus thresholds of 0 */
2362         if (!threshold)
2363                 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2364                          msg->addr);
2365         if (msg->len < threshold || msg->len == 0)
2366                 return NULL;
2367
2368         if (msg->flags & I2C_M_DMA_SAFE)
2369                 return msg->buf;
2370
2371         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2372                  msg->addr, msg->len);
2373
2374         if (msg->flags & I2C_M_RD)
2375                 return kzalloc(msg->len, GFP_KERNEL);
2376         else
2377                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2378 }
2379 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2380
2381 /**
2382  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2383  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2384  * @msg: the message which the buffer corresponds to
2385  * @xferred: bool saying if the message was transferred
2386  */
2387 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2388 {
2389         if (!buf || buf == msg->buf)
2390                 return;
2391
2392         if (xferred && msg->flags & I2C_M_RD)
2393                 memcpy(msg->buf, buf, msg->len);
2394
2395         kfree(buf);
2396 }
2397 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2398
2399 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2400 MODULE_DESCRIPTION("I2C-Bus main module");
2401 MODULE_LICENSE("GPL");