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;
 354
 355                 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 356                 if (wakeirq == -EPROBE_DEFER)
 357                         return wakeirq;
 358
 359                 device_init_wakeup(&client->dev, true);
 360
 361                 if (wakeirq > 0 && wakeirq != client->irq)
 362                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 363                 else if (client->irq > 0)
 364                         status = dev_pm_set_wake_irq(dev, client->irq);
 365                 else
 366                         status = 0;
 367
 368                 if (status)
 369                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 370         }
 371
 372         dev_dbg(dev, "probe\n");
 373
 374         status = of_clk_set_defaults(dev->of_node, false);
 375         if (status < 0)
 376                 goto err_clear_wakeup_irq;
 377
 378         status = dev_pm_domain_attach(&client->dev, true);
 379         if (status)
 380                 goto err_clear_wakeup_irq;
 381
 382         /*
 383          * When there are no more users of probe(),
 384          * rename probe_new to probe.
 385          */
 386         if (driver->probe_new)
 387                 status = driver->probe_new(client);
 388         else if (driver->probe)
 389                 status = driver->probe(client,
 390                                        i2c_match_id(driver->id_table, client));
 391         else
 392                 status = -EINVAL;
 393
 394         if (status)
 395                 goto err_detach_pm_domain;
 396
 397         return 0;
 398
 399 err_detach_pm_domain:
 400         dev_pm_domain_detach(&client->dev, true);
 401 err_clear_wakeup_irq:
 402         dev_pm_clear_wake_irq(&client->dev);
 403         device_init_wakeup(&client->dev, false);
 404         return status;
 405 }
 406
 407 static int i2c_device_remove(struct device *dev)
 408 {
 409         struct i2c_client       *client = i2c_verify_client(dev);
 410         struct i2c_driver       *driver;
 411         int status = 0;
 412
 413         if (!client || !dev->driver)
 414                 return 0;
 415
 416         driver = to_i2c_driver(dev->driver);
 417         if (driver->remove) {
 418                 dev_dbg(dev, "remove\n");
 419                 status = driver->remove(client);
 420         }
 421
 422         dev_pm_domain_detach(&client->dev, true);
 423
 424         dev_pm_clear_wake_irq(&client->dev);
 425         device_init_wakeup(&client->dev, false);
 426
 427         client->irq = 0;
 428         if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 429                 pm_runtime_put(&client->adapter->dev);
 430
 431         return status;
 432 }
 433
 434 static void i2c_device_shutdown(struct device *dev)
 435 {
 436         struct i2c_client *client = i2c_verify_client(dev);
 437         struct i2c_driver *driver;
 438
 439         if (!client || !dev->driver)
 440                 return;
 441         driver = to_i2c_driver(dev->driver);
 442         if (driver->shutdown)
 443                 driver->shutdown(client);
 444 }
 445
 446 static void i2c_client_dev_release(struct device *dev)
 447 {
 448         kfree(to_i2c_client(dev));
 449 }
 450
 451 static ssize_t
 452 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 453 {
 454         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 455                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 456 }
 457 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 458
 459 static ssize_t
 460 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 461 {
 462         struct i2c_client *client = to_i2c_client(dev);
 463         int len;
 464
 465         len = of_device_modalias(dev, buf, PAGE_SIZE);
 466         if (len != -ENODEV)
 467                 return len;
 468
 469         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 470         if (len != -ENODEV)
 471                 return len;
 472
 473         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 474 }
 475 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 476
 477 static struct attribute *i2c_dev_attrs[] = {
 478         &dev_attr_name.attr,
 479         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 480         &dev_attr_modalias.attr,
 481         NULL
 482 };
 483 ATTRIBUTE_GROUPS(i2c_dev);
 484
 485 struct bus_type i2c_bus_type = {
 486         .name           = "i2c",
 487         .match          = i2c_device_match,
 488         .probe          = i2c_device_probe,
 489         .remove         = i2c_device_remove,
 490         .shutdown       = i2c_device_shutdown,
 491 };
 492 EXPORT_SYMBOL_GPL(i2c_bus_type);
 493
 494 struct device_type i2c_client_type = {
 495         .groups         = i2c_dev_groups,
 496         .uevent         = i2c_device_uevent,
 497         .release        = i2c_client_dev_release,
 498 };
 499 EXPORT_SYMBOL_GPL(i2c_client_type);
 500
 501
 502 /**
 503  * i2c_verify_client - return parameter as i2c_client, or NULL
 504  * @dev: device, probably from some driver model iterator
 505  *
 506  * When traversing the driver model tree, perhaps using driver model
 507  * iterators like @device_for_each_child(), you can't assume very much
 508  * about the nodes you find.  Use this function to avoid oopses caused
 509  * by wrongly treating some non-I2C device as an i2c_client.
 510  */
 511 struct i2c_client *i2c_verify_client(struct device *dev)
 512 {
 513         return (dev->type == &i2c_client_type)
 514                         ? to_i2c_client(dev)
 515                         : NULL;
 516 }
 517 EXPORT_SYMBOL(i2c_verify_client);
 518
 519
 520 /* Return a unique address which takes the flags of the client into account */
 521 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 522 {
 523         unsigned short addr = client->addr;
 524
 525         /* For some client flags, add an arbitrary offset to avoid collisions */
 526         if (client->flags & I2C_CLIENT_TEN)
 527                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 528
 529         if (client->flags & I2C_CLIENT_SLAVE)
 530                 addr |= I2C_ADDR_OFFSET_SLAVE;
 531
 532         return addr;
 533 }
 534
 535 /* This is a permissive address validity check, I2C address map constraints
 536  * are purposely not enforced, except for the general call address. */
 537 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 538 {
 539         if (flags & I2C_CLIENT_TEN) {
 540                 /* 10-bit address, all values are valid */
 541                 if (addr > 0x3ff)
 542                         return -EINVAL;
 543         } else {
 544                 /* 7-bit address, reject the general call address */
 545                 if (addr == 0x00 || addr > 0x7f)
 546                         return -EINVAL;
 547         }
 548         return 0;
 549 }
 550
 551 /* And this is a strict address validity check, used when probing. If a
 552  * device uses a reserved address, then it shouldn't be probed. 7-bit
 553  * addressing is assumed, 10-bit address devices are rare and should be
 554  * explicitly enumerated. */
 555 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 556 {
 557         /*
 558          * Reserved addresses per I2C specification:
 559          *  0x00       General call address / START byte
 560          *  0x01       CBUS address
 561          *  0x02       Reserved for different bus format
 562          *  0x03       Reserved for future purposes
 563          *  0x04-0x07  Hs-mode master code
 564          *  0x78-0x7b  10-bit slave addressing
 565          *  0x7c-0x7f  Reserved for future purposes
 566          */
 567         if (addr < 0x08 || addr > 0x77)
 568                 return -EINVAL;
 569         return 0;
 570 }
 571
 572 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 573 {
 574         struct i2c_client       *client = i2c_verify_client(dev);
 575         int                     addr = *(int *)addrp;
 576
 577         if (client && i2c_encode_flags_to_addr(client) == addr)
 578                 return -EBUSY;
 579         return 0;
 580 }
 581
 582 /* walk up mux tree */
 583 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 584 {
 585         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 586         int result;
 587
 588         result = device_for_each_child(&adapter->dev, &addr,
 589                                         __i2c_check_addr_busy);
 590
 591         if (!result && parent)
 592                 result = i2c_check_mux_parents(parent, addr);
 593
 594         return result;
 595 }
 596
 597 /* recurse down mux tree */
 598 static int i2c_check_mux_children(struct device *dev, void *addrp)
 599 {
 600         int result;
 601
 602         if (dev->type == &i2c_adapter_type)
 603                 result = device_for_each_child(dev, addrp,
 604                                                 i2c_check_mux_children);
 605         else
 606                 result = __i2c_check_addr_busy(dev, addrp);
 607
 608         return result;
 609 }
 610
 611 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 612 {
 613         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 614         int result = 0;
 615
 616         if (parent)
 617                 result = i2c_check_mux_parents(parent, addr);
 618
 619         if (!result)
 620                 result = device_for_each_child(&adapter->dev, &addr,
 621                                                 i2c_check_mux_children);
 622
 623         return result;
 624 }
 625
 626 /**
 627  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 628  * @adapter: Target I2C bus segment
 629  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 630  *      locks only this branch in the adapter tree
 631  */
 632 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 633                                  unsigned int flags)
 634 {
 635         rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 636 }
 637
 638 /**
 639  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 640  * @adapter: Target I2C bus segment
 641  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 642  *      trylocks only this branch in the adapter tree
 643  */
 644 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 645                                    unsigned int flags)
 646 {
 647         return rt_mutex_trylock(&adapter->bus_lock);
 648 }
 649
 650 /**
 651  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 652  * @adapter: Target I2C bus segment
 653  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 654  *      unlocks only this branch in the adapter tree
 655  */
 656 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 657                                    unsigned int flags)
 658 {
 659         rt_mutex_unlock(&adapter->bus_lock);
 660 }
 661
 662 static void i2c_dev_set_name(struct i2c_adapter *adap,
 663                              struct i2c_client *client,
 664                              struct i2c_board_info const *info)
 665 {
 666         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 667
 668         if (info && info->dev_name) {
 669                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 670                 return;
 671         }
 672
 673         if (adev) {
 674                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 675                 return;
 676         }
 677
 678         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 679                      i2c_encode_flags_to_addr(client));
 680 }
 681
 682 int i2c_dev_irq_from_resources(const struct resource *resources,
 683                                unsigned int num_resources)
 684 {
 685         struct irq_data *irqd;
 686         int i;
 687
 688         for (i = 0; i < num_resources; i++) {
 689                 const struct resource *r = &resources[i];
 690
 691                 if (resource_type(r) != IORESOURCE_IRQ)
 692                         continue;
 693
 694                 if (r->flags & IORESOURCE_BITS) {
 695                         irqd = irq_get_irq_data(r->start);
 696                         if (!irqd)
 697                                 break;
 698
 699                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 700                 }
 701
 702                 return r->start;
 703         }
 704
 705         return 0;
 706 }
 707
 708 /**
 709  * i2c_new_client_device - instantiate an i2c device
 710  * @adap: the adapter managing the device
 711  * @info: describes one I2C device; bus_num is ignored
 712  * Context: can sleep
 713  *
 714  * Create an i2c device. Binding is handled through driver model
 715  * probe()/remove() methods.  A driver may be bound to this device when we
 716  * return from this function, or any later moment (e.g. maybe hotplugging will
 717  * load the driver module).  This call is not appropriate for use by mainboard
 718  * initialization logic, which usually runs during an arch_initcall() long
 719  * before any i2c_adapter could exist.
 720  *
 721  * This returns the new i2c client, which may be saved for later use with
 722  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 723  */
 724 struct i2c_client *
 725 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 726 {
 727         struct i2c_client       *client;
 728         int                     status;
 729
 730         client = kzalloc(sizeof *client, GFP_KERNEL);
 731         if (!client)
 732                 return ERR_PTR(-ENOMEM);
 733
 734         client->adapter = adap;
 735
 736         client->dev.platform_data = info->platform_data;
 737         client->flags = info->flags;
 738         client->addr = info->addr;
 739
 740         client->init_irq = info->irq;
 741         if (!client->init_irq)
 742                 client->init_irq = i2c_dev_irq_from_resources(info->resources,
 743                                                          info->num_resources);
 744
 745         strlcpy(client->name, info->type, sizeof(client->name));
 746
 747         status = i2c_check_addr_validity(client->addr, client->flags);
 748         if (status) {
 749                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 750                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 751                 goto out_err_silent;
 752         }
 753
 754         /* Check for address business */
 755         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 756         if (status)
 757                 goto out_err;
 758
 759         client->dev.parent = &client->adapter->dev;
 760         client->dev.bus = &i2c_bus_type;
 761         client->dev.type = &i2c_client_type;
 762         client->dev.of_node = of_node_get(info->of_node);
 763         client->dev.fwnode = info->fwnode;
 764
 765         i2c_dev_set_name(adap, client, info);
 766
 767         if (info->properties) {
 768                 status = device_add_properties(&client->dev, info->properties);
 769                 if (status) {
 770                         dev_err(&adap->dev,
 771                                 "Failed to add properties to client %s: %d\n",
 772                                 client->name, status);
 773                         goto out_err_put_of_node;
 774                 }
 775         }
 776
 777         status = device_register(&client->dev);
 778         if (status)
 779                 goto out_free_props;
 780
 781         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 782                 client->name, dev_name(&client->dev));
 783
 784         return client;
 785
 786 out_free_props:
 787         if (info->properties)
 788                 device_remove_properties(&client->dev);
 789 out_err_put_of_node:
 790         of_node_put(info->of_node);
 791 out_err:
 792         dev_err(&adap->dev,
 793                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 794                 client->name, client->addr, status);
 795 out_err_silent:
 796         kfree(client);
 797         return ERR_PTR(status);
 798 }
 799 EXPORT_SYMBOL_GPL(i2c_new_client_device);
 800
 801 /**
 802  * i2c_new_device - instantiate an i2c device
 803  * @adap: the adapter managing the device
 804  * @info: describes one I2C device; bus_num is ignored
 805  * Context: can sleep
 806  *
 807  * This deprecated function has the same functionality as
 808  * @i2c_new_client_device, it just returns NULL instead of an ERR_PTR in case of
 809  * an error for compatibility with current I2C API. It will be removed once all
 810  * users are converted.
 811  *
 812  * This returns the new i2c client, which may be saved for later use with
 813  * i2c_unregister_device(); or NULL to indicate an error.
 814  */
 815 struct i2c_client *
 816 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 817 {
 818         struct i2c_client *ret;
 819
 820         ret = i2c_new_client_device(adap, info);
 821         return IS_ERR(ret) ? NULL : ret;
 822 }
 823 EXPORT_SYMBOL_GPL(i2c_new_device);
 824
 825
 826 /**
 827  * i2c_unregister_device - reverse effect of i2c_new_device()
 828  * @client: value returned from i2c_new_device()
 829  * Context: can sleep
 830  */
 831 void i2c_unregister_device(struct i2c_client *client)
 832 {
 833         if (IS_ERR_OR_NULL(client))
 834                 return;
 835
 836         if (client->dev.of_node) {
 837                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 838                 of_node_put(client->dev.of_node);
 839         }
 840
 841         if (ACPI_COMPANION(&client->dev))
 842                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 843         device_unregister(&client->dev);
 844 }
 845 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 846
 847
 848 static const struct i2c_device_id dummy_id[] = {
 849         { "dummy", 0 },
 850         { },
 851 };
 852
 853 static int dummy_probe(struct i2c_client *client,
 854                        const struct i2c_device_id *id)
 855 {
 856         return 0;
 857 }
 858
 859 static int dummy_remove(struct i2c_client *client)
 860 {
 861         return 0;
 862 }
 863
 864 static struct i2c_driver dummy_driver = {
 865         .driver.name    = "dummy",
 866         .probe          = dummy_probe,
 867         .remove         = dummy_remove,
 868         .id_table       = dummy_id,
 869 };
 870
 871 /**
 872  * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 873  * @adapter: the adapter managing the device
 874  * @address: seven bit address to be used
 875  * Context: can sleep
 876  *
 877  * This returns an I2C client bound to the "dummy" driver, intended for use
 878  * with devices that consume multiple addresses.  Examples of such chips
 879  * include various EEPROMS (like 24c04 and 24c08 models).
 880  *
 881  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 882  * except i2c_transfer() need a client handle; the dummy will be that handle.
 883  * And second, this prevents the specified address from being bound to a
 884  * different driver.
 885  *
 886  * This returns the new i2c client, which should be saved for later use with
 887  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 888  */
 889 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
 890 {
 891         struct i2c_board_info info = {
 892                 I2C_BOARD_INFO("dummy", address),
 893         };
 894
 895         return i2c_new_client_device(adapter, &info);
 896 }
 897 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
 898
 899 /**
 900  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 901  * @adapter: the adapter managing the device
 902  * @address: seven bit address to be used
 903  * Context: can sleep
 904  *
 905  * This deprecated function has the same functionality as @i2c_new_dummy_device,
 906  * it just returns NULL instead of an ERR_PTR in case of an error for
 907  * compatibility with current I2C API. It will be removed once all users are
 908  * converted.
 909  *
 910  * This returns the new i2c client, which should be saved for later use with
 911  * i2c_unregister_device(); or NULL to indicate an error.
 912  */
 913 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 914 {
 915         struct i2c_client *ret;
 916
 917         ret = i2c_new_dummy_device(adapter, address);
 918         return IS_ERR(ret) ? NULL : ret;
 919 }
 920 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 921
 922 struct i2c_dummy_devres {
 923         struct i2c_client *client;
 924 };
 925
 926 static void devm_i2c_release_dummy(struct device *dev, void *res)
 927 {
 928         struct i2c_dummy_devres *this = res;
 929
 930         i2c_unregister_device(this->client);
 931 }
 932
 933 /**
 934  * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
 935  * @dev: device the managed resource is bound to
 936  * @adapter: the adapter managing the device
 937  * @address: seven bit address to be used
 938  * Context: can sleep
 939  *
 940  * This is the device-managed version of @i2c_new_dummy_device. It returns the
 941  * new i2c client or an ERR_PTR in case of an error.
 942  */
 943 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
 944                                              struct i2c_adapter *adapter,
 945                                              u16 address)
 946 {
 947         struct i2c_dummy_devres *dr;
 948         struct i2c_client *client;
 949
 950         dr = devres_alloc(devm_i2c_release_dummy, sizeof(*dr), GFP_KERNEL);
 951         if (!dr)
 952                 return ERR_PTR(-ENOMEM);
 953
 954         client = i2c_new_dummy_device(adapter, address);
 955         if (IS_ERR(client)) {
 956                 devres_free(dr);
 957         } else {
 958                 dr->client = client;
 959                 devres_add(dev, dr);
 960         }
 961
 962         return client;
 963 }
 964 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
 965
 966 /**
 967  * i2c_new_ancillary_device - Helper to get the instantiated secondary address
 968  * and create the associated device
 969  * @client: Handle to the primary client
 970  * @name: Handle to specify which secondary address to get
 971  * @default_addr: Used as a fallback if no secondary address was specified
 972  * Context: can sleep
 973  *
 974  * I2C clients can be composed of multiple I2C slaves bound together in a single
 975  * component. The I2C client driver then binds to the master I2C slave and needs
 976  * to create I2C dummy clients to communicate with all the other slaves.
 977  *
 978  * This function creates and returns an I2C dummy client whose I2C address is
 979  * retrieved from the platform firmware based on the given slave name. If no
 980  * address is specified by the firmware default_addr is used.
 981  *
 982  * On DT-based platforms the address is retrieved from the "reg" property entry
 983  * cell whose "reg-names" value matches the slave name.
 984  *
 985  * This returns the new i2c client, which should be saved for later use with
 986  * i2c_unregister_device(); or an ERR_PTR to describe the error.
 987  */
 988 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
 989                                                 const char *name,
 990                                                 u16 default_addr)
 991 {
 992         struct device_node *np = client->dev.of_node;
 993         u32 addr = default_addr;
 994         int i;
 995
 996         if (np) {
 997                 i = of_property_match_string(np, "reg-names", name);
 998                 if (i >= 0)
 999                         of_property_read_u32_index(np, "reg", i, &addr);
1000         }
1001
1002         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1003         return i2c_new_dummy_device(client->adapter, addr);
1004 }
1005 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1006
1007 /* ------------------------------------------------------------------------- */
1008
1009 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1010
1011 static void i2c_adapter_dev_release(struct device *dev)
1012 {
1013         struct i2c_adapter *adap = to_i2c_adapter(dev);
1014         complete(&adap->dev_released);
1015 }
1016
1017 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1018 {
1019         unsigned int depth = 0;
1020
1021         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1022                 depth++;
1023
1024         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1025                   "adapter depth exceeds lockdep subclass limit\n");
1026
1027         return depth;
1028 }
1029 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1030
1031 /*
1032  * Let users instantiate I2C devices through sysfs. This can be used when
1033  * platform initialization code doesn't contain the proper data for
1034  * whatever reason. Also useful for drivers that do device detection and
1035  * detection fails, either because the device uses an unexpected address,
1036  * or this is a compatible device with different ID register values.
1037  *
1038  * Parameter checking may look overzealous, but we really don't want
1039  * the user to provide incorrect parameters.
1040  */
1041 static ssize_t
1042 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1043                      const char *buf, size_t count)
1044 {
1045         struct i2c_adapter *adap = to_i2c_adapter(dev);
1046         struct i2c_board_info info;
1047         struct i2c_client *client;
1048         char *blank, end;
1049         int res;
1050
1051         memset(&info, 0, sizeof(struct i2c_board_info));
1052
1053         blank = strchr(buf, ' ');
1054         if (!blank) {
1055                 dev_err(dev, "%s: Missing parameters\n", "new_device");
1056                 return -EINVAL;
1057         }
1058         if (blank - buf > I2C_NAME_SIZE - 1) {
1059                 dev_err(dev, "%s: Invalid device name\n", "new_device");
1060                 return -EINVAL;
1061         }
1062         memcpy(info.type, buf, blank - buf);
1063
1064         /* Parse remaining parameters, reject extra parameters */
1065         res = sscanf(++blank, "%hi%c", &info.addr, &end);
1066         if (res < 1) {
1067                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1068                 return -EINVAL;
1069         }
1070         if (res > 1  && end != '\n') {
1071                 dev_err(dev, "%s: Extra parameters\n", "new_device");
1072                 return -EINVAL;
1073         }
1074
1075         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1076                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1077                 info.flags |= I2C_CLIENT_TEN;
1078         }
1079
1080         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1081                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1082                 info.flags |= I2C_CLIENT_SLAVE;
1083         }
1084
1085         client = i2c_new_client_device(adap, &info);
1086         if (IS_ERR(client))
1087                 return PTR_ERR(client);
1088
1089         /* Keep track of the added device */
1090         mutex_lock(&adap->userspace_clients_lock);
1091         list_add_tail(&client->detected, &adap->userspace_clients);
1092         mutex_unlock(&adap->userspace_clients_lock);
1093         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1094                  info.type, info.addr);
1095
1096         return count;
1097 }
1098 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1099
1100 /*
1101  * And of course let the users delete the devices they instantiated, if
1102  * they got it wrong. This interface can only be used to delete devices
1103  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1104  * don't delete devices to which some kernel code still has references.
1105  *
1106  * Parameter checking may look overzealous, but we really don't want
1107  * the user to delete the wrong device.
1108  */
1109 static ssize_t
1110 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1111                         const char *buf, size_t count)
1112 {
1113         struct i2c_adapter *adap = to_i2c_adapter(dev);
1114         struct i2c_client *client, *next;
1115         unsigned short addr;
1116         char end;
1117         int res;
1118
1119         /* Parse parameters, reject extra parameters */
1120         res = sscanf(buf, "%hi%c", &addr, &end);
1121         if (res < 1) {
1122                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1123                 return -EINVAL;
1124         }
1125         if (res > 1  && end != '\n') {
1126                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1127                 return -EINVAL;
1128         }
1129
1130         /* Make sure the device was added through sysfs */
1131         res = -ENOENT;
1132         mutex_lock_nested(&adap->userspace_clients_lock,
1133                           i2c_adapter_depth(adap));
1134         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1135                                  detected) {
1136                 if (i2c_encode_flags_to_addr(client) == addr) {
1137                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1138                                  "delete_device", client->name, client->addr);
1139
1140                         list_del(&client->detected);
1141                         i2c_unregister_device(client);
1142                         res = count;
1143                         break;
1144                 }
1145         }
1146         mutex_unlock(&adap->userspace_clients_lock);
1147
1148         if (res < 0)
1149                 dev_err(dev, "%s: Can't find device in list\n",
1150                         "delete_device");
1151         return res;
1152 }
1153 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1154                                    i2c_sysfs_delete_device);
1155
1156 static struct attribute *i2c_adapter_attrs[] = {
1157         &dev_attr_name.attr,
1158         &dev_attr_new_device.attr,
1159         &dev_attr_delete_device.attr,
1160         NULL
1161 };
1162 ATTRIBUTE_GROUPS(i2c_adapter);
1163
1164 struct device_type i2c_adapter_type = {
1165         .groups         = i2c_adapter_groups,
1166         .release        = i2c_adapter_dev_release,
1167 };
1168 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1169
1170 /**
1171  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1172  * @dev: device, probably from some driver model iterator
1173  *
1174  * When traversing the driver model tree, perhaps using driver model
1175  * iterators like @device_for_each_child(), you can't assume very much
1176  * about the nodes you find.  Use this function to avoid oopses caused
1177  * by wrongly treating some non-I2C device as an i2c_adapter.
1178  */
1179 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1180 {
1181         return (dev->type == &i2c_adapter_type)
1182                         ? to_i2c_adapter(dev)
1183                         : NULL;
1184 }
1185 EXPORT_SYMBOL(i2c_verify_adapter);
1186
1187 #ifdef CONFIG_I2C_COMPAT
1188 static struct class_compat *i2c_adapter_compat_class;
1189 #endif
1190
1191 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1192 {
1193         struct i2c_devinfo      *devinfo;
1194
1195         down_read(&__i2c_board_lock);
1196         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1197                 if (devinfo->busnum == adapter->nr
1198                                 && !i2c_new_device(adapter,
1199                                                 &devinfo->board_info))
1200                         dev_err(&adapter->dev,
1201                                 "Can't create device at 0x%02x\n",
1202                                 devinfo->board_info.addr);
1203         }
1204         up_read(&__i2c_board_lock);
1205 }
1206
1207 static int i2c_do_add_adapter(struct i2c_driver *driver,
1208                               struct i2c_adapter *adap)
1209 {
1210         /* Detect supported devices on that bus, and instantiate them */
1211         i2c_detect(adap, driver);
1212
1213         return 0;
1214 }
1215
1216 static int __process_new_adapter(struct device_driver *d, void *data)
1217 {
1218         return i2c_do_add_adapter(to_i2c_driver(d), data);
1219 }
1220
1221 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1222         .lock_bus =    i2c_adapter_lock_bus,
1223         .trylock_bus = i2c_adapter_trylock_bus,
1224         .unlock_bus =  i2c_adapter_unlock_bus,
1225 };
1226
1227 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1228 {
1229         struct irq_domain *domain = adap->host_notify_domain;
1230         irq_hw_number_t hwirq;
1231
1232         if (!domain)
1233                 return;
1234
1235         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1236                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1237
1238         irq_domain_remove(domain);
1239         adap->host_notify_domain = NULL;
1240 }
1241
1242 static int i2c_host_notify_irq_map(struct irq_domain *h,
1243                                           unsigned int virq,
1244                                           irq_hw_number_t hw_irq_num)
1245 {
1246         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1247
1248         return 0;
1249 }
1250
1251 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1252         .map = i2c_host_notify_irq_map,
1253 };
1254
1255 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1256 {
1257         struct irq_domain *domain;
1258
1259         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1260                 return 0;
1261
1262         domain = irq_domain_create_linear(adap->dev.fwnode,
1263                                           I2C_ADDR_7BITS_COUNT,
1264                                           &i2c_host_notify_irq_ops, adap);
1265         if (!domain)
1266                 return -ENOMEM;
1267
1268         adap->host_notify_domain = domain;
1269
1270         return 0;
1271 }
1272
1273 /**
1274  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1275  * I2C client.
1276  * @adap: the adapter
1277  * @addr: the I2C address of the notifying device
1278  * Context: can't sleep
1279  *
1280  * Helper function to be called from an I2C bus driver's interrupt
1281  * handler. It will schedule the Host Notify IRQ.
1282  */
1283 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1284 {
1285         int irq;
1286
1287         if (!adap)
1288                 return -EINVAL;
1289
1290         irq = irq_find_mapping(adap->host_notify_domain, addr);
1291         if (irq <= 0)
1292                 return -ENXIO;
1293
1294         generic_handle_irq(irq);
1295
1296         return 0;
1297 }
1298 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1299
1300 static int i2c_register_adapter(struct i2c_adapter *adap)
1301 {
1302         int res = -EINVAL;
1303
1304         /* Can't register until after driver model init */
1305         if (WARN_ON(!is_registered)) {
1306                 res = -EAGAIN;
1307                 goto out_list;
1308         }
1309
1310         /* Sanity checks */
1311         if (WARN(!adap->name[0], "i2c adapter has no name"))
1312                 goto out_list;
1313
1314         if (!adap->algo) {
1315                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1316                 goto out_list;
1317         }
1318
1319         if (!adap->lock_ops)
1320                 adap->lock_ops = &i2c_adapter_lock_ops;
1321
1322         adap->locked_flags = 0;
1323         rt_mutex_init(&adap->bus_lock);
1324         rt_mutex_init(&adap->mux_lock);
1325         mutex_init(&adap->userspace_clients_lock);
1326         INIT_LIST_HEAD(&adap->userspace_clients);
1327
1328         /* Set default timeout to 1 second if not already set */
1329         if (adap->timeout == 0)
1330                 adap->timeout = HZ;
1331
1332         /* register soft irqs for Host Notify */
1333         res = i2c_setup_host_notify_irq_domain(adap);
1334         if (res) {
1335                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1336                        adap->name, res);
1337                 goto out_list;
1338         }
1339
1340         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1341         adap->dev.bus = &i2c_bus_type;
1342         adap->dev.type = &i2c_adapter_type;
1343         res = device_register(&adap->dev);
1344         if (res) {
1345                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1346                 goto out_list;
1347         }
1348
1349         res = of_i2c_setup_smbus_alert(adap);
1350         if (res)
1351                 goto out_reg;
1352
1353         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1354
1355         pm_runtime_no_callbacks(&adap->dev);
1356         pm_suspend_ignore_children(&adap->dev, true);
1357         pm_runtime_enable(&adap->dev);
1358
1359 #ifdef CONFIG_I2C_COMPAT
1360         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1361                                        adap->dev.parent);
1362         if (res)
1363                 dev_warn(&adap->dev,
1364                          "Failed to create compatibility class link\n");
1365 #endif
1366
1367         i2c_init_recovery(adap);
1368
1369         /* create pre-declared device nodes */
1370         of_i2c_register_devices(adap);
1371         i2c_acpi_register_devices(adap);
1372         i2c_acpi_install_space_handler(adap);
1373
1374         if (adap->nr < __i2c_first_dynamic_bus_num)
1375                 i2c_scan_static_board_info(adap);
1376
1377         /* Notify drivers */
1378         mutex_lock(&core_lock);
1379         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1380         mutex_unlock(&core_lock);
1381
1382         return 0;
1383
1384 out_reg:
1385         init_completion(&adap->dev_released);
1386         device_unregister(&adap->dev);
1387         wait_for_completion(&adap->dev_released);
1388 out_list:
1389         mutex_lock(&core_lock);
1390         idr_remove(&i2c_adapter_idr, adap->nr);
1391         mutex_unlock(&core_lock);
1392         return res;
1393 }
1394
1395 /**
1396  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1397  * @adap: the adapter to register (with adap->nr initialized)
1398  * Context: can sleep
1399  *
1400  * See i2c_add_numbered_adapter() for details.
1401  */
1402 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1403 {
1404         int id;
1405
1406         mutex_lock(&core_lock);
1407         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1408         mutex_unlock(&core_lock);
1409         if (WARN(id < 0, "couldn't get idr"))
1410                 return id == -ENOSPC ? -EBUSY : id;
1411
1412         return i2c_register_adapter(adap);
1413 }
1414
1415 /**
1416  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1417  * @adapter: the adapter to add
1418  * Context: can sleep
1419  *
1420  * This routine is used to declare an I2C adapter when its bus number
1421  * doesn't matter or when its bus number is specified by an dt alias.
1422  * Examples of bases when the bus number doesn't matter: I2C adapters
1423  * dynamically added by USB links or PCI plugin cards.
1424  *
1425  * When this returns zero, a new bus number was allocated and stored
1426  * in adap->nr, and the specified adapter became available for clients.
1427  * Otherwise, a negative errno value is returned.
1428  */
1429 int i2c_add_adapter(struct i2c_adapter *adapter)
1430 {
1431         struct device *dev = &adapter->dev;
1432         int id;
1433
1434         if (dev->of_node) {
1435                 id = of_alias_get_id(dev->of_node, "i2c");
1436                 if (id >= 0) {
1437                         adapter->nr = id;
1438                         return __i2c_add_numbered_adapter(adapter);
1439                 }
1440         }
1441
1442         mutex_lock(&core_lock);
1443         id = idr_alloc(&i2c_adapter_idr, adapter,
1444                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1445         mutex_unlock(&core_lock);
1446         if (WARN(id < 0, "couldn't get idr"))
1447                 return id;
1448
1449         adapter->nr = id;
1450
1451         return i2c_register_adapter(adapter);
1452 }
1453 EXPORT_SYMBOL(i2c_add_adapter);
1454
1455 /**
1456  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1457  * @adap: the adapter to register (with adap->nr initialized)
1458  * Context: can sleep
1459  *
1460  * This routine is used to declare an I2C adapter when its bus number
1461  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1462  * or otherwise built in to the system's mainboard, and where i2c_board_info
1463  * is used to properly configure I2C devices.
1464  *
1465  * If the requested bus number is set to -1, then this function will behave
1466  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1467  *
1468  * If no devices have pre-been declared for this bus, then be sure to
1469  * register the adapter before any dynamically allocated ones.  Otherwise
1470  * the required bus ID may not be available.
1471  *
1472  * When this returns zero, the specified adapter became available for
1473  * clients using the bus number provided in adap->nr.  Also, the table
1474  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1475  * and the appropriate driver model device nodes are created.  Otherwise, a
1476  * negative errno value is returned.
1477  */
1478 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1479 {
1480         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1481                 return i2c_add_adapter(adap);
1482
1483         return __i2c_add_numbered_adapter(adap);
1484 }
1485 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1486
1487 static void i2c_do_del_adapter(struct i2c_driver *driver,
1488                               struct i2c_adapter *adapter)
1489 {
1490         struct i2c_client *client, *_n;
1491
1492         /* Remove the devices we created ourselves as the result of hardware
1493          * probing (using a driver's detect method) */
1494         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1495                 if (client->adapter == adapter) {
1496                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1497                                 client->name, client->addr);
1498                         list_del(&client->detected);
1499                         i2c_unregister_device(client);
1500                 }
1501         }
1502 }
1503
1504 static int __unregister_client(struct device *dev, void *dummy)
1505 {
1506         struct i2c_client *client = i2c_verify_client(dev);
1507         if (client && strcmp(client->name, "dummy"))
1508                 i2c_unregister_device(client);
1509         return 0;
1510 }
1511
1512 static int __unregister_dummy(struct device *dev, void *dummy)
1513 {
1514         struct i2c_client *client = i2c_verify_client(dev);
1515         i2c_unregister_device(client);
1516         return 0;
1517 }
1518
1519 static int __process_removed_adapter(struct device_driver *d, void *data)
1520 {
1521         i2c_do_del_adapter(to_i2c_driver(d), data);
1522         return 0;
1523 }
1524
1525 /**
1526  * i2c_del_adapter - unregister I2C adapter
1527  * @adap: the adapter being unregistered
1528  * Context: can sleep
1529  *
1530  * This unregisters an I2C adapter which was previously registered
1531  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1532  */
1533 void i2c_del_adapter(struct i2c_adapter *adap)
1534 {
1535         struct i2c_adapter *found;
1536         struct i2c_client *client, *next;
1537
1538         /* First make sure that this adapter was ever added */
1539         mutex_lock(&core_lock);
1540         found = idr_find(&i2c_adapter_idr, adap->nr);
1541         mutex_unlock(&core_lock);
1542         if (found != adap) {
1543                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1544                 return;
1545         }
1546
1547         i2c_acpi_remove_space_handler(adap);
1548         /* Tell drivers about this removal */
1549         mutex_lock(&core_lock);
1550         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1551                                __process_removed_adapter);
1552         mutex_unlock(&core_lock);
1553
1554         /* Remove devices instantiated from sysfs */
1555         mutex_lock_nested(&adap->userspace_clients_lock,
1556                           i2c_adapter_depth(adap));
1557         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1558                                  detected) {
1559                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1560                         client->addr);
1561                 list_del(&client->detected);
1562                 i2c_unregister_device(client);
1563         }
1564         mutex_unlock(&adap->userspace_clients_lock);
1565
1566         /* Detach any active clients. This can't fail, thus we do not
1567          * check the returned value. This is a two-pass process, because
1568          * we can't remove the dummy devices during the first pass: they
1569          * could have been instantiated by real devices wishing to clean
1570          * them up properly, so we give them a chance to do that first. */
1571         device_for_each_child(&adap->dev, NULL, __unregister_client);
1572         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1573
1574 #ifdef CONFIG_I2C_COMPAT
1575         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1576                                  adap->dev.parent);
1577 #endif
1578
1579         /* device name is gone after device_unregister */
1580         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1581
1582         pm_runtime_disable(&adap->dev);
1583
1584         i2c_host_notify_irq_teardown(adap);
1585
1586         /* wait until all references to the device are gone
1587          *
1588          * FIXME: This is old code and should ideally be replaced by an
1589          * alternative which results in decoupling the lifetime of the struct
1590          * device from the i2c_adapter, like spi or netdev do. Any solution
1591          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1592          */
1593         init_completion(&adap->dev_released);
1594         device_unregister(&adap->dev);
1595         wait_for_completion(&adap->dev_released);
1596
1597         /* free bus id */
1598         mutex_lock(&core_lock);
1599         idr_remove(&i2c_adapter_idr, adap->nr);
1600         mutex_unlock(&core_lock);
1601
1602         /* Clear the device structure in case this adapter is ever going to be
1603            added again */
1604         memset(&adap->dev, 0, sizeof(adap->dev));
1605 }
1606 EXPORT_SYMBOL(i2c_del_adapter);
1607
1608 /**
1609  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1610  * @dev: The device to scan for I2C timing properties
1611  * @t: the i2c_timings struct to be filled with values
1612  * @use_defaults: bool to use sane defaults derived from the I2C specification
1613  *                when properties are not found, otherwise use 0
1614  *
1615  * Scan the device for the generic I2C properties describing timing parameters
1616  * for the signal and fill the given struct with the results. If a property was
1617  * not found and use_defaults was true, then maximum timings are assumed which
1618  * are derived from the I2C specification. If use_defaults is not used, the
1619  * results will be 0, so drivers can apply their own defaults later. The latter
1620  * is mainly intended for avoiding regressions of existing drivers which want
1621  * to switch to this function. New drivers almost always should use the defaults.
1622  */
1623
1624 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1625 {
1626         int ret;
1627
1628         memset(t, 0, sizeof(*t));
1629
1630         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1631         if (ret && use_defaults)
1632                 t->bus_freq_hz = 100000;
1633
1634         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1635         if (ret && use_defaults) {
1636                 if (t->bus_freq_hz <= 100000)
1637                         t->scl_rise_ns = 1000;
1638                 else if (t->bus_freq_hz <= 400000)
1639                         t->scl_rise_ns = 300;
1640                 else
1641                         t->scl_rise_ns = 120;
1642         }
1643
1644         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1645         if (ret && use_defaults) {
1646                 if (t->bus_freq_hz <= 400000)
1647                         t->scl_fall_ns = 300;
1648                 else
1649                         t->scl_fall_ns = 120;
1650         }
1651
1652         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1653
1654         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1655         if (ret && use_defaults)
1656                 t->sda_fall_ns = t->scl_fall_ns;
1657
1658         device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1659 }
1660 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1661
1662 /* ------------------------------------------------------------------------- */
1663
1664 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1665 {
1666         int res;
1667
1668         mutex_lock(&core_lock);
1669         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1670         mutex_unlock(&core_lock);
1671
1672         return res;
1673 }
1674 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1675
1676 static int __process_new_driver(struct device *dev, void *data)
1677 {
1678         if (dev->type != &i2c_adapter_type)
1679                 return 0;
1680         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1681 }
1682
1683 /*
1684  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1685  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1686  */
1687
1688 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1689 {
1690         int res;
1691
1692         /* Can't register until after driver model init */
1693         if (WARN_ON(!is_registered))
1694                 return -EAGAIN;
1695
1696         /* add the driver to the list of i2c drivers in the driver core */
1697         driver->driver.owner = owner;
1698         driver->driver.bus = &i2c_bus_type;
1699         INIT_LIST_HEAD(&driver->clients);
1700
1701         /* When registration returns, the driver core
1702          * will have called probe() for all matching-but-unbound devices.
1703          */
1704         res = driver_register(&driver->driver);
1705         if (res)
1706                 return res;
1707
1708         pr_debug("driver [%s] registered\n", driver->driver.name);
1709
1710         /* Walk the adapters that are already present */
1711         i2c_for_each_dev(driver, __process_new_driver);
1712
1713         return 0;
1714 }
1715 EXPORT_SYMBOL(i2c_register_driver);
1716
1717 static int __process_removed_driver(struct device *dev, void *data)
1718 {
1719         if (dev->type == &i2c_adapter_type)
1720                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1721         return 0;
1722 }
1723
1724 /**
1725  * i2c_del_driver - unregister I2C driver
1726  * @driver: the driver being unregistered
1727  * Context: can sleep
1728  */
1729 void i2c_del_driver(struct i2c_driver *driver)
1730 {
1731         i2c_for_each_dev(driver, __process_removed_driver);
1732
1733         driver_unregister(&driver->driver);
1734         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1735 }
1736 EXPORT_SYMBOL(i2c_del_driver);
1737
1738 /* ------------------------------------------------------------------------- */
1739
1740 /**
1741  * i2c_use_client - increments the reference count of the i2c client structure
1742  * @client: the client being referenced
1743  *
1744  * Each live reference to a client should be refcounted. The driver model does
1745  * that automatically as part of driver binding, so that most drivers don't
1746  * need to do this explicitly: they hold a reference until they're unbound
1747  * from the device.
1748  *
1749  * A pointer to the client with the incremented reference counter is returned.
1750  */
1751 struct i2c_client *i2c_use_client(struct i2c_client *client)
1752 {
1753         if (client && get_device(&client->dev))
1754                 return client;
1755         return NULL;
1756 }
1757 EXPORT_SYMBOL(i2c_use_client);
1758
1759 /**
1760  * i2c_release_client - release a use of the i2c client structure
1761  * @client: the client being no longer referenced
1762  *
1763  * Must be called when a user of a client is finished with it.
1764  */
1765 void i2c_release_client(struct i2c_client *client)
1766 {
1767         if (client)
1768                 put_device(&client->dev);
1769 }
1770 EXPORT_SYMBOL(i2c_release_client);
1771
1772 struct i2c_cmd_arg {
1773         unsigned        cmd;
1774         void            *arg;
1775 };
1776
1777 static int i2c_cmd(struct device *dev, void *_arg)
1778 {
1779         struct i2c_client       *client = i2c_verify_client(dev);
1780         struct i2c_cmd_arg      *arg = _arg;
1781         struct i2c_driver       *driver;
1782
1783         if (!client || !client->dev.driver)
1784                 return 0;
1785
1786         driver = to_i2c_driver(client->dev.driver);
1787         if (driver->command)
1788                 driver->command(client, arg->cmd, arg->arg);
1789         return 0;
1790 }
1791
1792 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1793 {
1794         struct i2c_cmd_arg      cmd_arg;
1795
1796         cmd_arg.cmd = cmd;
1797         cmd_arg.arg = arg;
1798         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1799 }
1800 EXPORT_SYMBOL(i2c_clients_command);
1801
1802 static int __init i2c_init(void)
1803 {
1804         int retval;
1805
1806         retval = of_alias_get_highest_id("i2c");
1807
1808         down_write(&__i2c_board_lock);
1809         if (retval >= __i2c_first_dynamic_bus_num)
1810                 __i2c_first_dynamic_bus_num = retval + 1;
1811         up_write(&__i2c_board_lock);
1812
1813         retval = bus_register(&i2c_bus_type);
1814         if (retval)
1815                 return retval;
1816
1817         is_registered = true;
1818
1819 #ifdef CONFIG_I2C_COMPAT
1820         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1821         if (!i2c_adapter_compat_class) {
1822                 retval = -ENOMEM;
1823                 goto bus_err;
1824         }
1825 #endif
1826         retval = i2c_add_driver(&dummy_driver);
1827         if (retval)
1828                 goto class_err;
1829
1830         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1831                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1832         if (IS_ENABLED(CONFIG_ACPI))
1833                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1834
1835         return 0;
1836
1837 class_err:
1838 #ifdef CONFIG_I2C_COMPAT
1839         class_compat_unregister(i2c_adapter_compat_class);
1840 bus_err:
1841 #endif
1842         is_registered = false;
1843         bus_unregister(&i2c_bus_type);
1844         return retval;
1845 }
1846
1847 static void __exit i2c_exit(void)
1848 {
1849         if (IS_ENABLED(CONFIG_ACPI))
1850                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1851         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1852                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1853         i2c_del_driver(&dummy_driver);
1854 #ifdef CONFIG_I2C_COMPAT
1855         class_compat_unregister(i2c_adapter_compat_class);
1856 #endif
1857         bus_unregister(&i2c_bus_type);
1858         tracepoint_synchronize_unregister();
1859 }
1860
1861 /* We must initialize early, because some subsystems register i2c drivers
1862  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1863  */
1864 postcore_initcall(i2c_init);
1865 module_exit(i2c_exit);
1866
1867 /* ----------------------------------------------------
1868  * the functional interface to the i2c busses.
1869  * ----------------------------------------------------
1870  */
1871
1872 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1873 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1874
1875 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1876 {
1877         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1878                             err_msg, msg->addr, msg->len,
1879                             msg->flags & I2C_M_RD ? "read" : "write");
1880         return -EOPNOTSUPP;
1881 }
1882
1883 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1884 {
1885         const struct i2c_adapter_quirks *q = adap->quirks;
1886         int max_num = q->max_num_msgs, i;
1887         bool do_len_check = true;
1888
1889         if (q->flags & I2C_AQ_COMB) {
1890                 max_num = 2;
1891
1892                 /* special checks for combined messages */
1893                 if (num == 2) {
1894                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1895                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1896
1897                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1898                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1899
1900                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1901                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1902
1903                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1904                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1905
1906                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1907                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1908
1909                         do_len_check = false;
1910                 }
1911         }
1912
1913         if (i2c_quirk_exceeded(num, max_num))
1914                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1915
1916         for (i = 0; i < num; i++) {
1917                 u16 len = msgs[i].len;
1918
1919                 if (msgs[i].flags & I2C_M_RD) {
1920                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1921                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1922
1923                         if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1924                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1925                 } else {
1926                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1927                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1928
1929                         if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1930                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1931                 }
1932         }
1933
1934         return 0;
1935 }
1936
1937 /**
1938  * __i2c_transfer - unlocked flavor of i2c_transfer
1939  * @adap: Handle to I2C bus
1940  * @msgs: One or more messages to execute before STOP is issued to
1941  *      terminate the operation; each message begins with a START.
1942  * @num: Number of messages to be executed.
1943  *
1944  * Returns negative errno, else the number of messages executed.
1945  *
1946  * Adapter lock must be held when calling this function. No debug logging
1947  * takes place. adap->algo->master_xfer existence isn't checked.
1948  */
1949 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1950 {
1951         unsigned long orig_jiffies;
1952         int ret, try;
1953
1954         if (WARN_ON(!msgs || num < 1))
1955                 return -EINVAL;
1956
1957         ret = __i2c_check_suspended(adap);
1958         if (ret)
1959                 return ret;
1960
1961         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1962                 return -EOPNOTSUPP;
1963
1964         /*
1965          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1966          * enabled.  This is an efficient way of keeping the for-loop from
1967          * being executed when not needed.
1968          */
1969         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1970                 int i;
1971                 for (i = 0; i < num; i++)
1972                         if (msgs[i].flags & I2C_M_RD)
1973                                 trace_i2c_read(adap, &msgs[i], i);
1974                         else
1975                                 trace_i2c_write(adap, &msgs[i], i);
1976         }
1977
1978         /* Retry automatically on arbitration loss */
1979         orig_jiffies = jiffies;
1980         for (ret = 0, try = 0; try <= adap->retries; try++) {
1981                 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1982                         ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1983                 else
1984                         ret = adap->algo->master_xfer(adap, msgs, num);
1985
1986                 if (ret != -EAGAIN)
1987                         break;
1988                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1989                         break;
1990         }
1991
1992         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1993                 int i;
1994                 for (i = 0; i < ret; i++)
1995                         if (msgs[i].flags & I2C_M_RD)
1996                                 trace_i2c_reply(adap, &msgs[i], i);
1997                 trace_i2c_result(adap, num, ret);
1998         }
1999
2000         return ret;
2001 }
2002 EXPORT_SYMBOL(__i2c_transfer);
2003
2004 /**
2005  * i2c_transfer - execute a single or combined I2C message
2006  * @adap: Handle to I2C bus
2007  * @msgs: One or more messages to execute before STOP is issued to
2008  *      terminate the operation; each message begins with a START.
2009  * @num: Number of messages to be executed.
2010  *
2011  * Returns negative errno, else the number of messages executed.
2012  *
2013  * Note that there is no requirement that each message be sent to
2014  * the same slave address, although that is the most common model.
2015  */
2016 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2017 {
2018         int ret;
2019
2020         if (!adap->algo->master_xfer) {
2021                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2022                 return -EOPNOTSUPP;
2023         }
2024
2025         /* REVISIT the fault reporting model here is weak:
2026          *
2027          *  - When we get an error after receiving N bytes from a slave,
2028          *    there is no way to report "N".
2029          *
2030          *  - When we get a NAK after transmitting N bytes to a slave,
2031          *    there is no way to report "N" ... or to let the master
2032          *    continue executing the rest of this combined message, if
2033          *    that's the appropriate response.
2034          *
2035          *  - When for example "num" is two and we successfully complete
2036          *    the first message but get an error part way through the
2037          *    second, it's unclear whether that should be reported as
2038          *    one (discarding status on the second message) or errno
2039          *    (discarding status on the first one).
2040          */
2041         ret = __i2c_lock_bus_helper(adap);
2042         if (ret)
2043                 return ret;
2044
2045         ret = __i2c_transfer(adap, msgs, num);
2046         i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2047
2048         return ret;
2049 }
2050 EXPORT_SYMBOL(i2c_transfer);
2051
2052 /**
2053  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2054  *                             to/from a buffer
2055  * @client: Handle to slave device
2056  * @buf: Where the data is stored
2057  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2058  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2059  *
2060  * Returns negative errno, or else the number of bytes transferred.
2061  */
2062 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2063                               int count, u16 flags)
2064 {
2065         int ret;
2066         struct i2c_msg msg = {
2067                 .addr = client->addr,
2068                 .flags = flags | (client->flags & I2C_M_TEN),
2069                 .len = count,
2070                 .buf = buf,
2071         };
2072
2073         ret = i2c_transfer(client->adapter, &msg, 1);
2074
2075         /*
2076          * If everything went ok (i.e. 1 msg transferred), return #bytes
2077          * transferred, else error code.
2078          */
2079         return (ret == 1) ? count : ret;
2080 }
2081 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2082
2083 /**
2084  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2085  * @client: The device to query
2086  * @id: The queried information
2087  *
2088  * Returns negative errno on error, zero on success.
2089  */
2090 int i2c_get_device_id(const struct i2c_client *client,
2091                       struct i2c_device_identity *id)
2092 {
2093         struct i2c_adapter *adap = client->adapter;
2094         union i2c_smbus_data raw_id;
2095         int ret;
2096
2097         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2098                 return -EOPNOTSUPP;
2099
2100         raw_id.block[0] = 3;
2101         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2102                              I2C_SMBUS_READ, client->addr << 1,
2103                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2104         if (ret)
2105                 return ret;
2106
2107         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2108         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2109         id->die_revision = raw_id.block[3] & 0x7;
2110         return 0;
2111 }
2112 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2113
2114 /* ----------------------------------------------------
2115  * the i2c address scanning function
2116  * Will not work for 10-bit addresses!
2117  * ----------------------------------------------------
2118  */
2119
2120 /*
2121  * Legacy default probe function, mostly relevant for SMBus. The default
2122  * probe method is a quick write, but it is known to corrupt the 24RF08
2123  * EEPROMs due to a state machine bug, and could also irreversibly
2124  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2125  * we use a short byte read instead. Also, some bus drivers don't implement
2126  * quick write, so we fallback to a byte read in that case too.
2127  * On x86, there is another special case for FSC hardware monitoring chips,
2128  * which want regular byte reads (address 0x73.) Fortunately, these are the
2129  * only known chips using this I2C address on PC hardware.
2130  * Returns 1 if probe succeeded, 0 if not.
2131  */
2132 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2133 {
2134         int err;
2135         union i2c_smbus_data dummy;
2136
2137 #ifdef CONFIG_X86
2138         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2139          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2140                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2141                                      I2C_SMBUS_BYTE_DATA, &dummy);
2142         else
2143 #endif
2144         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2145          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2146                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2147                                      I2C_SMBUS_QUICK, NULL);
2148         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2149                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2150                                      I2C_SMBUS_BYTE, &dummy);
2151         else {
2152                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2153                          addr);
2154                 err = -EOPNOTSUPP;
2155         }
2156
2157         return err >= 0;
2158 }
2159
2160 static int i2c_detect_address(struct i2c_client *temp_client,
2161                               struct i2c_driver *driver)
2162 {
2163         struct i2c_board_info info;
2164         struct i2c_adapter *adapter = temp_client->adapter;
2165         int addr = temp_client->addr;
2166         int err;
2167
2168         /* Make sure the address is valid */
2169         err = i2c_check_7bit_addr_validity_strict(addr);
2170         if (err) {
2171                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2172                          addr);
2173                 return err;
2174         }
2175
2176         /* Skip if already in use (7 bit, no need to encode flags) */
2177         if (i2c_check_addr_busy(adapter, addr))
2178                 return 0;
2179
2180         /* Make sure there is something at this address */
2181         if (!i2c_default_probe(adapter, addr))
2182                 return 0;
2183
2184         /* Finally call the custom detection function */
2185         memset(&info, 0, sizeof(struct i2c_board_info));
2186         info.addr = addr;
2187         err = driver->detect(temp_client, &info);
2188         if (err) {
2189                 /* -ENODEV is returned if the detection fails. We catch it
2190                    here as this isn't an error. */
2191                 return err == -ENODEV ? 0 : err;
2192         }
2193
2194         /* Consistency check */
2195         if (info.type[0] == '\0') {
2196                 dev_err(&adapter->dev,
2197                         "%s detection function provided no name for 0x%x\n",
2198                         driver->driver.name, addr);
2199         } else {
2200                 struct i2c_client *client;
2201
2202                 /* Detection succeeded, instantiate the device */
2203                 if (adapter->class & I2C_CLASS_DEPRECATED)
2204                         dev_warn(&adapter->dev,
2205                                 "This adapter will soon drop class based instantiation of devices. "
2206                                 "Please make sure client 0x%02x gets instantiated by other means. "
2207                                 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2208                                 info.addr);
2209
2210                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2211                         info.type, info.addr);
2212                 client = i2c_new_device(adapter, &info);
2213                 if (client)
2214                         list_add_tail(&client->detected, &driver->clients);
2215                 else
2216                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2217                                 info.type, info.addr);
2218         }
2219         return 0;
2220 }
2221
2222 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2223 {
2224         const unsigned short *address_list;
2225         struct i2c_client *temp_client;
2226         int i, err = 0;
2227         int adap_id = i2c_adapter_id(adapter);
2228
2229         address_list = driver->address_list;
2230         if (!driver->detect || !address_list)
2231                 return 0;
2232
2233         /* Warn that the adapter lost class based instantiation */
2234         if (adapter->class == I2C_CLASS_DEPRECATED) {
2235                 dev_dbg(&adapter->dev,
2236                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2237                         "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2238                         driver->driver.name);
2239                 return 0;
2240         }
2241
2242         /* Stop here if the classes do not match */
2243         if (!(adapter->class & driver->class))
2244                 return 0;
2245
2246         /* Set up a temporary client to help detect callback */
2247         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2248         if (!temp_client)
2249                 return -ENOMEM;
2250         temp_client->adapter = adapter;
2251
2252         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2253                 dev_dbg(&adapter->dev,
2254                         "found normal entry for adapter %d, addr 0x%02x\n",
2255                         adap_id, address_list[i]);
2256                 temp_client->addr = address_list[i];
2257                 err = i2c_detect_address(temp_client, driver);
2258                 if (unlikely(err))
2259                         break;
2260         }
2261
2262         kfree(temp_client);
2263         return err;
2264 }
2265
2266 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2267 {
2268         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2269                               I2C_SMBUS_QUICK, NULL) >= 0;
2270 }
2271 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2272
2273 struct i2c_client *
2274 i2c_new_probed_device(struct i2c_adapter *adap,
2275                       struct i2c_board_info *info,
2276                       unsigned short const *addr_list,
2277                       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2278 {
2279         int i;
2280
2281         if (!probe)
2282                 probe = i2c_default_probe;
2283
2284         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2285                 /* Check address validity */
2286                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2287                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2288                                  addr_list[i]);
2289                         continue;
2290                 }
2291
2292                 /* Check address availability (7 bit, no need to encode flags) */
2293                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2294                         dev_dbg(&adap->dev,
2295                                 "Address 0x%02x already in use, not probing\n",
2296                                 addr_list[i]);
2297                         continue;
2298                 }
2299
2300                 /* Test address responsiveness */
2301                 if (probe(adap, addr_list[i]))
2302                         break;
2303         }
2304
2305         if (addr_list[i] == I2C_CLIENT_END) {
2306                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2307                 return NULL;
2308         }
2309
2310         info->addr = addr_list[i];
2311         return i2c_new_device(adap, info);
2312 }
2313 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2314
2315 struct i2c_adapter *i2c_get_adapter(int nr)
2316 {
2317         struct i2c_adapter *adapter;
2318
2319         mutex_lock(&core_lock);
2320         adapter = idr_find(&i2c_adapter_idr, nr);
2321         if (!adapter)
2322                 goto exit;
2323
2324         if (try_module_get(adapter->owner))
2325                 get_device(&adapter->dev);
2326         else
2327                 adapter = NULL;
2328
2329  exit:
2330         mutex_unlock(&core_lock);
2331         return adapter;
2332 }
2333 EXPORT_SYMBOL(i2c_get_adapter);
2334
2335 void i2c_put_adapter(struct i2c_adapter *adap)
2336 {
2337         if (!adap)
2338                 return;
2339
2340         put_device(&adap->dev);
2341         module_put(adap->owner);
2342 }
2343 EXPORT_SYMBOL(i2c_put_adapter);
2344
2345 /**
2346  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2347  * @msg: the message to be checked
2348  * @threshold: the minimum number of bytes for which using DMA makes sense.
2349  *             Should at least be 1.
2350  *
2351  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2352  *         Or a valid pointer to be used with DMA. After use, release it by
2353  *         calling i2c_put_dma_safe_msg_buf().
2354  *
2355  * This function must only be called from process context!
2356  */
2357 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2358 {
2359         /* also skip 0-length msgs for bogus thresholds of 0 */
2360         if (!threshold)
2361                 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2362                          msg->addr);
2363         if (msg->len < threshold || msg->len == 0)
2364                 return NULL;
2365
2366         if (msg->flags & I2C_M_DMA_SAFE)
2367                 return msg->buf;
2368
2369         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2370                  msg->addr, msg->len);
2371
2372         if (msg->flags & I2C_M_RD)
2373                 return kzalloc(msg->len, GFP_KERNEL);
2374         else
2375                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2376 }
2377 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2378
2379 /**
2380  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2381  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2382  * @msg: the message which the buffer corresponds to
2383  * @xferred: bool saying if the message was transferred
2384  */
2385 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2386 {
2387         if (!buf || buf == msg->buf)
2388                 return;
2389
2390         if (xferred && msg->flags & I2C_M_RD)
2391                 memcpy(msg->buf, buf, msg->len);
2392
2393         kfree(buf);
2394 }
2395 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2396
2397 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2398 MODULE_DESCRIPTION("I2C-Bus main module");
2399 MODULE_LICENSE("GPL");