drivers/i2c/i2c-core-base.c

   1 /*
   2  * Linux I2C core
   3  *
   4  * Copyright (C) 1995-99 Simon G. Vogl
   5  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   6  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   7  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   8  *
   9  * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  19  */
  20
  21 #define pr_fmt(fmt) "i2c-core: " fmt
  22
  23 #include <dt-bindings/i2c/i2c.h>
  24 #include <linux/acpi.h>
  25 #include <linux/clk/clk-conf.h>
  26 #include <linux/completion.h>
  27 #include <linux/delay.h>
  28 #include <linux/err.h>
  29 #include <linux/errno.h>
  30 #include <linux/gpio/consumer.h>
  31 #include <linux/i2c.h>
  32 #include <linux/i2c-smbus.h>
  33 #include <linux/idr.h>
  34 #include <linux/init.h>
  35 #include <linux/irqflags.h>
  36 #include <linux/jump_label.h>
  37 #include <linux/kernel.h>
  38 #include <linux/module.h>
  39 #include <linux/mutex.h>
  40 #include <linux/of_device.h>
  41 #include <linux/of.h>
  42 #include <linux/of_irq.h>
  43 #include <linux/pm_domain.h>
  44 #include <linux/pm_runtime.h>
  45 #include <linux/pm_wakeirq.h>
  46 #include <linux/property.h>
  47 #include <linux/rwsem.h>
  48 #include <linux/slab.h>
  49
  50 #include "i2c-core.h"
  51
  52 #define CREATE_TRACE_POINTS
  53 #include <trace/events/i2c.h>
  54
  55 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
  56 #define I2C_ADDR_OFFSET_SLAVE   0x1000
  57
  58 #define I2C_ADDR_7BITS_MAX      0x77
  59 #define I2C_ADDR_7BITS_COUNT    (I2C_ADDR_7BITS_MAX + 1)
  60
  61 #define I2C_ADDR_DEVICE_ID      0x7c
  62
  63 /*
  64  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  65  * deletion of detected devices are serialized
  66  */
  67 static DEFINE_MUTEX(core_lock);
  68 static DEFINE_IDR(i2c_adapter_idr);
  69
  70 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  71
  72 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
  73 static bool is_registered;
  74
  75 int i2c_transfer_trace_reg(void)
  76 {
  77         static_branch_inc(&i2c_trace_msg_key);
  78         return 0;
  79 }
  80
  81 void i2c_transfer_trace_unreg(void)
  82 {
  83         static_branch_dec(&i2c_trace_msg_key);
  84 }
  85
  86 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  87                                                 const struct i2c_client *client)
  88 {
  89         if (!(id && client))
  90                 return NULL;
  91
  92         while (id->name[0]) {
  93                 if (strcmp(client->name, id->name) == 0)
  94                         return id;
  95                 id++;
  96         }
  97         return NULL;
  98 }
  99 EXPORT_SYMBOL_GPL(i2c_match_id);
 100
 101 static int i2c_device_match(struct device *dev, struct device_driver *drv)
 102 {
 103         struct i2c_client       *client = i2c_verify_client(dev);
 104         struct i2c_driver       *driver;
 105
 106
 107         /* Attempt an OF style match */
 108         if (i2c_of_match_device(drv->of_match_table, client))
 109                 return 1;
 110
 111         /* Then ACPI style match */
 112         if (acpi_driver_match_device(dev, drv))
 113                 return 1;
 114
 115         driver = to_i2c_driver(drv);
 116
 117         /* Finally an I2C match */
 118         if (i2c_match_id(driver->id_table, client))
 119                 return 1;
 120
 121         return 0;
 122 }
 123
 124 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 125 {
 126         struct i2c_client *client = to_i2c_client(dev);
 127         int rc;
 128
 129         rc = of_device_uevent_modalias(dev, env);
 130         if (rc != -ENODEV)
 131                 return rc;
 132
 133         rc = acpi_device_uevent_modalias(dev, env);
 134         if (rc != -ENODEV)
 135                 return rc;
 136
 137         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 138 }
 139
 140 /* i2c bus recovery routines */
 141 static int get_scl_gpio_value(struct i2c_adapter *adap)
 142 {
 143         return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 144 }
 145
 146 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 147 {
 148         gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 149 }
 150
 151 static int get_sda_gpio_value(struct i2c_adapter *adap)
 152 {
 153         return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 154 }
 155
 156 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 157 {
 158         gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 159 }
 160
 161 static int i2c_generic_bus_free(struct i2c_adapter *adap)
 162 {
 163         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 164         int ret = -EOPNOTSUPP;
 165
 166         if (bri->get_bus_free)
 167                 ret = bri->get_bus_free(adap);
 168         else if (bri->get_sda)
 169                 ret = bri->get_sda(adap);
 170
 171         if (ret < 0)
 172                 return ret;
 173
 174         return ret ? 0 : -EBUSY;
 175 }
 176
 177 /*
 178  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 179  * We will generate clock with rate 100 KHz and so duration of both clock levels
 180  * is: delay in ns = (10^6 / 100) / 2
 181  */
 182 #define RECOVERY_NDELAY         5000
 183 #define RECOVERY_CLK_CNT        9
 184
 185 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 186 {
 187         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 188         int i = 0, scl = 1, ret = 0;
 189
 190         if (bri->prepare_recovery)
 191                 bri->prepare_recovery(adap);
 192
 193         /*
 194          * If we can set SDA, we will always create a STOP to ensure additional
 195          * pulses will do no harm. This is achieved by letting SDA follow SCL
 196          * half a cycle later. Check the 'incomplete_write_byte' fault injector
 197          * for details.
 198          */
 199         bri->set_scl(adap, scl);
 200         ndelay(RECOVERY_NDELAY / 2);
 201         if (bri->set_sda)
 202                 bri->set_sda(adap, scl);
 203         ndelay(RECOVERY_NDELAY / 2);
 204
 205         /*
 206          * By this time SCL is high, as we need to give 9 falling-rising edges
 207          */
 208         while (i++ < RECOVERY_CLK_CNT * 2) {
 209                 if (scl) {
 210                         /* SCL shouldn't be low here */
 211                         if (!bri->get_scl(adap)) {
 212                                 dev_err(&adap->dev,
 213                                         "SCL is stuck low, exit recovery\n");
 214                                 ret = -EBUSY;
 215                                 break;
 216                         }
 217                 }
 218
 219                 scl = !scl;
 220                 bri->set_scl(adap, scl);
 221                 /* Creating STOP again, see above */
 222                 ndelay(RECOVERY_NDELAY / 2);
 223                 if (bri->set_sda)
 224                         bri->set_sda(adap, scl);
 225                 ndelay(RECOVERY_NDELAY / 2);
 226
 227                 if (scl) {
 228                         ret = i2c_generic_bus_free(adap);
 229                         if (ret == 0)
 230                                 break;
 231                 }
 232         }
 233
 234         /* If we can't check bus status, assume recovery worked */
 235         if (ret == -EOPNOTSUPP)
 236                 ret = 0;
 237
 238         if (bri->unprepare_recovery)
 239                 bri->unprepare_recovery(adap);
 240
 241         return ret;
 242 }
 243 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 244
 245 int i2c_recover_bus(struct i2c_adapter *adap)
 246 {
 247         if (!adap->bus_recovery_info)
 248                 return -EOPNOTSUPP;
 249
 250         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 251         return adap->bus_recovery_info->recover_bus(adap);
 252 }
 253 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 254
 255 static void i2c_init_recovery(struct i2c_adapter *adap)
 256 {
 257         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 258         char *err_str;
 259
 260         if (!bri)
 261                 return;
 262
 263         if (!bri->recover_bus) {
 264                 err_str = "no recover_bus() found";
 265                 goto err;
 266         }
 267
 268         if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 269                 bri->get_scl = get_scl_gpio_value;
 270                 bri->set_scl = set_scl_gpio_value;
 271                 if (bri->sda_gpiod) {
 272                         bri->get_sda = get_sda_gpio_value;
 273                         /* FIXME: add proper flag instead of '0' once available */
 274                         if (gpiod_get_direction(bri->sda_gpiod) == 0)
 275                                 bri->set_sda = set_sda_gpio_value;
 276                 }
 277                 return;
 278         }
 279
 280         if (bri->recover_bus == i2c_generic_scl_recovery) {
 281                 /* Generic SCL recovery */
 282                 if (!bri->set_scl || !bri->get_scl) {
 283                         err_str = "no {get|set}_scl() found";
 284                         goto err;
 285                 }
 286                 if (!bri->set_sda && !bri->get_sda) {
 287                         err_str = "either get_sda() or set_sda() needed";
 288                         goto err;
 289                 }
 290         }
 291
 292         return;
 293  err:
 294         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 295         adap->bus_recovery_info = NULL;
 296 }
 297
 298 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 299 {
 300         struct i2c_adapter *adap = client->adapter;
 301         unsigned int irq;
 302
 303         if (!adap->host_notify_domain)
 304                 return -ENXIO;
 305
 306         if (client->flags & I2C_CLIENT_TEN)
 307                 return -EINVAL;
 308
 309         irq = irq_create_mapping(adap->host_notify_domain, client->addr);
 310
 311         return irq > 0 ? irq : -ENXIO;
 312 }
 313
 314 static int i2c_device_probe(struct device *dev)
 315 {
 316         struct i2c_client       *client = i2c_verify_client(dev);
 317         struct i2c_driver       *driver;
 318         int status;
 319
 320         if (!client)
 321                 return 0;
 322
 323         driver = to_i2c_driver(dev->driver);
 324
 325         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 326                 int irq = -ENOENT;
 327
 328                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 329                         dev_dbg(dev, "Using Host Notify IRQ\n");
 330                         /* Keep adapter active when Host Notify is required */
 331                         pm_runtime_get_sync(&client->adapter->dev);
 332                         irq = i2c_smbus_host_notify_to_irq(client);
 333                 } else if (dev->of_node) {
 334                         irq = of_irq_get_byname(dev->of_node, "irq");
 335                         if (irq == -EINVAL || irq == -ENODATA)
 336                                 irq = of_irq_get(dev->of_node, 0);
 337                 } else if (ACPI_COMPANION(dev)) {
 338                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 339                 }
 340                 if (irq == -EPROBE_DEFER)
 341                         return irq;
 342
 343                 if (irq < 0)
 344                         irq = 0;
 345
 346                 client->irq = irq;
 347         }
 348
 349         /*
 350          * An I2C ID table is not mandatory, if and only if, a suitable OF
 351          * or ACPI ID table is supplied for the probing device.
 352          */
 353         if (!driver->id_table &&
 354             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 355             !i2c_of_match_device(dev->driver->of_match_table, client))
 356                 return -ENODEV;
 357
 358         if (client->flags & I2C_CLIENT_WAKE) {
 359                 int wakeirq = -ENOENT;
 360
 361                 if (dev->of_node) {
 362                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 363                         if (wakeirq == -EPROBE_DEFER)
 364                                 return wakeirq;
 365                 }
 366
 367                 device_init_wakeup(&client->dev, true);
 368
 369                 if (wakeirq > 0 && wakeirq != client->irq)
 370                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 371                 else if (client->irq > 0)
 372                         status = dev_pm_set_wake_irq(dev, client->irq);
 373                 else
 374                         status = 0;
 375
 376                 if (status)
 377                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 378         }
 379
 380         dev_dbg(dev, "probe\n");
 381
 382         status = of_clk_set_defaults(dev->of_node, false);
 383         if (status < 0)
 384                 goto err_clear_wakeup_irq;
 385
 386         status = dev_pm_domain_attach(&client->dev, true);
 387         if (status)
 388                 goto err_clear_wakeup_irq;
 389
 390         /*
 391          * When there are no more users of probe(),
 392          * rename probe_new to probe.
 393          */
 394         if (driver->probe_new)
 395                 status = driver->probe_new(client);
 396         else if (driver->probe)
 397                 status = driver->probe(client,
 398                                        i2c_match_id(driver->id_table, client));
 399         else
 400                 status = -EINVAL;
 401
 402         if (status)
 403                 goto err_detach_pm_domain;
 404
 405         return 0;
 406
 407 err_detach_pm_domain:
 408         dev_pm_domain_detach(&client->dev, true);
 409 err_clear_wakeup_irq:
 410         dev_pm_clear_wake_irq(&client->dev);
 411         device_init_wakeup(&client->dev, false);
 412         return status;
 413 }
 414
 415 static int i2c_device_remove(struct device *dev)
 416 {
 417         struct i2c_client       *client = i2c_verify_client(dev);
 418         struct i2c_driver       *driver;
 419         int status = 0;
 420
 421         if (!client || !dev->driver)
 422                 return 0;
 423
 424         driver = to_i2c_driver(dev->driver);
 425         if (driver->remove) {
 426                 dev_dbg(dev, "remove\n");
 427                 status = driver->remove(client);
 428         }
 429
 430         dev_pm_domain_detach(&client->dev, true);
 431
 432         dev_pm_clear_wake_irq(&client->dev);
 433         device_init_wakeup(&client->dev, false);
 434
 435         client->irq = client->init_irq;
 436         if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 437                 pm_runtime_put(&client->adapter->dev);
 438
 439         return status;
 440 }
 441
 442 static void i2c_device_shutdown(struct device *dev)
 443 {
 444         struct i2c_client *client = i2c_verify_client(dev);
 445         struct i2c_driver *driver;
 446
 447         if (!client || !dev->driver)
 448                 return;
 449         driver = to_i2c_driver(dev->driver);
 450         if (driver->shutdown)
 451                 driver->shutdown(client);
 452 }
 453
 454 static void i2c_client_dev_release(struct device *dev)
 455 {
 456         kfree(to_i2c_client(dev));
 457 }
 458
 459 static ssize_t
 460 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 461 {
 462         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 463                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 464 }
 465 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 466
 467 static ssize_t
 468 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 469 {
 470         struct i2c_client *client = to_i2c_client(dev);
 471         int len;
 472
 473         len = of_device_modalias(dev, buf, PAGE_SIZE);
 474         if (len != -ENODEV)
 475                 return len;
 476
 477         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 478         if (len != -ENODEV)
 479                 return len;
 480
 481         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 482 }
 483 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 484
 485 static struct attribute *i2c_dev_attrs[] = {
 486         &dev_attr_name.attr,
 487         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 488         &dev_attr_modalias.attr,
 489         NULL
 490 };
 491 ATTRIBUTE_GROUPS(i2c_dev);
 492
 493 struct bus_type i2c_bus_type = {
 494         .name           = "i2c",
 495         .match          = i2c_device_match,
 496         .probe          = i2c_device_probe,
 497         .remove         = i2c_device_remove,
 498         .shutdown       = i2c_device_shutdown,
 499 };
 500 EXPORT_SYMBOL_GPL(i2c_bus_type);
 501
 502 struct device_type i2c_client_type = {
 503         .groups         = i2c_dev_groups,
 504         .uevent         = i2c_device_uevent,
 505         .release        = i2c_client_dev_release,
 506 };
 507 EXPORT_SYMBOL_GPL(i2c_client_type);
 508
 509
 510 /**
 511  * i2c_verify_client - return parameter as i2c_client, or NULL
 512  * @dev: device, probably from some driver model iterator
 513  *
 514  * When traversing the driver model tree, perhaps using driver model
 515  * iterators like @device_for_each_child(), you can't assume very much
 516  * about the nodes you find.  Use this function to avoid oopses caused
 517  * by wrongly treating some non-I2C device as an i2c_client.
 518  */
 519 struct i2c_client *i2c_verify_client(struct device *dev)
 520 {
 521         return (dev->type == &i2c_client_type)
 522                         ? to_i2c_client(dev)
 523                         : NULL;
 524 }
 525 EXPORT_SYMBOL(i2c_verify_client);
 526
 527
 528 /* Return a unique address which takes the flags of the client into account */
 529 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 530 {
 531         unsigned short addr = client->addr;
 532
 533         /* For some client flags, add an arbitrary offset to avoid collisions */
 534         if (client->flags & I2C_CLIENT_TEN)
 535                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 536
 537         if (client->flags & I2C_CLIENT_SLAVE)
 538                 addr |= I2C_ADDR_OFFSET_SLAVE;
 539
 540         return addr;
 541 }
 542
 543 /* This is a permissive address validity check, I2C address map constraints
 544  * are purposely not enforced, except for the general call address. */
 545 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 546 {
 547         if (flags & I2C_CLIENT_TEN) {
 548                 /* 10-bit address, all values are valid */
 549                 if (addr > 0x3ff)
 550                         return -EINVAL;
 551         } else {
 552                 /* 7-bit address, reject the general call address */
 553                 if (addr == 0x00 || addr > 0x7f)
 554                         return -EINVAL;
 555         }
 556         return 0;
 557 }
 558
 559 /* And this is a strict address validity check, used when probing. If a
 560  * device uses a reserved address, then it shouldn't be probed. 7-bit
 561  * addressing is assumed, 10-bit address devices are rare and should be
 562  * explicitly enumerated. */
 563 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 564 {
 565         /*
 566          * Reserved addresses per I2C specification:
 567          *  0x00       General call address / START byte
 568          *  0x01       CBUS address
 569          *  0x02       Reserved for different bus format
 570          *  0x03       Reserved for future purposes
 571          *  0x04-0x07  Hs-mode master code
 572          *  0x78-0x7b  10-bit slave addressing
 573          *  0x7c-0x7f  Reserved for future purposes
 574          */
 575         if (addr < 0x08 || addr > 0x77)
 576                 return -EINVAL;
 577         return 0;
 578 }
 579
 580 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 581 {
 582         struct i2c_client       *client = i2c_verify_client(dev);
 583         int                     addr = *(int *)addrp;
 584
 585         if (client && i2c_encode_flags_to_addr(client) == addr)
 586                 return -EBUSY;
 587         return 0;
 588 }
 589
 590 /* walk up mux tree */
 591 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 592 {
 593         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 594         int result;
 595
 596         result = device_for_each_child(&adapter->dev, &addr,
 597                                         __i2c_check_addr_busy);
 598
 599         if (!result && parent)
 600                 result = i2c_check_mux_parents(parent, addr);
 601
 602         return result;
 603 }
 604
 605 /* recurse down mux tree */
 606 static int i2c_check_mux_children(struct device *dev, void *addrp)
 607 {
 608         int result;
 609
 610         if (dev->type == &i2c_adapter_type)
 611                 result = device_for_each_child(dev, addrp,
 612                                                 i2c_check_mux_children);
 613         else
 614                 result = __i2c_check_addr_busy(dev, addrp);
 615
 616         return result;
 617 }
 618
 619 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 620 {
 621         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 622         int result = 0;
 623
 624         if (parent)
 625                 result = i2c_check_mux_parents(parent, addr);
 626
 627         if (!result)
 628                 result = device_for_each_child(&adapter->dev, &addr,
 629                                                 i2c_check_mux_children);
 630
 631         return result;
 632 }
 633
 634 /**
 635  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 636  * @adapter: Target I2C bus segment
 637  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 638  *      locks only this branch in the adapter tree
 639  */
 640 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 641                                  unsigned int flags)
 642 {
 643         rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 644 }
 645
 646 /**
 647  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 648  * @adapter: Target I2C bus segment
 649  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 650  *      trylocks only this branch in the adapter tree
 651  */
 652 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 653                                    unsigned int flags)
 654 {
 655         return rt_mutex_trylock(&adapter->bus_lock);
 656 }
 657
 658 /**
 659  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 660  * @adapter: Target I2C bus segment
 661  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 662  *      unlocks only this branch in the adapter tree
 663  */
 664 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 665                                    unsigned int flags)
 666 {
 667         rt_mutex_unlock(&adapter->bus_lock);
 668 }
 669
 670 static void i2c_dev_set_name(struct i2c_adapter *adap,
 671                              struct i2c_client *client,
 672                              struct i2c_board_info const *info)
 673 {
 674         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 675
 676         if (info && info->dev_name) {
 677                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 678                 return;
 679         }
 680
 681         if (adev) {
 682                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 683                 return;
 684         }
 685
 686         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 687                      i2c_encode_flags_to_addr(client));
 688 }
 689
 690 static int i2c_dev_irq_from_resources(const struct resource *resources,
 691                                       unsigned int num_resources)
 692 {
 693         struct irq_data *irqd;
 694         int i;
 695
 696         for (i = 0; i < num_resources; i++) {
 697                 const struct resource *r = &resources[i];
 698
 699                 if (resource_type(r) != IORESOURCE_IRQ)
 700                         continue;
 701
 702                 if (r->flags & IORESOURCE_BITS) {
 703                         irqd = irq_get_irq_data(r->start);
 704                         if (!irqd)
 705                                 break;
 706
 707                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 708                 }
 709
 710                 return r->start;
 711         }
 712
 713         return 0;
 714 }
 715
 716 /**
 717  * i2c_new_device - instantiate an i2c device
 718  * @adap: the adapter managing the device
 719  * @info: describes one I2C device; bus_num is ignored
 720  * Context: can sleep
 721  *
 722  * Create an i2c device. Binding is handled through driver model
 723  * probe()/remove() methods.  A driver may be bound to this device when we
 724  * return from this function, or any later moment (e.g. maybe hotplugging will
 725  * load the driver module).  This call is not appropriate for use by mainboard
 726  * initialization logic, which usually runs during an arch_initcall() long
 727  * before any i2c_adapter could exist.
 728  *
 729  * This returns the new i2c client, which may be saved for later use with
 730  * i2c_unregister_device(); or NULL to indicate an error.
 731  */
 732 struct i2c_client *
 733 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 734 {
 735         struct i2c_client       *client;
 736         int                     status;
 737
 738         client = kzalloc(sizeof *client, GFP_KERNEL);
 739         if (!client)
 740                 return NULL;
 741
 742         client->adapter = adap;
 743
 744         client->dev.platform_data = info->platform_data;
 745         client->flags = info->flags;
 746         client->addr = info->addr;
 747
 748         client->init_irq = info->irq;
 749         if (!client->init_irq)
 750                 client->init_irq = i2c_dev_irq_from_resources(info->resources,
 751                                                          info->num_resources);
 752         client->irq = client->init_irq;
 753
 754         strlcpy(client->name, info->type, sizeof(client->name));
 755
 756         status = i2c_check_addr_validity(client->addr, client->flags);
 757         if (status) {
 758                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 759                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 760                 goto out_err_silent;
 761         }
 762
 763         /* Check for address business */
 764         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 765         if (status)
 766                 goto out_err;
 767
 768         client->dev.parent = &client->adapter->dev;
 769         client->dev.bus = &i2c_bus_type;
 770         client->dev.type = &i2c_client_type;
 771         client->dev.of_node = of_node_get(info->of_node);
 772         client->dev.fwnode = info->fwnode;
 773
 774         i2c_dev_set_name(adap, client, info);
 775
 776         if (info->properties) {
 777                 status = device_add_properties(&client->dev, info->properties);
 778                 if (status) {
 779                         dev_err(&adap->dev,
 780                                 "Failed to add properties to client %s: %d\n",
 781                                 client->name, status);
 782                         goto out_err_put_of_node;
 783                 }
 784         }
 785
 786         status = device_register(&client->dev);
 787         if (status)
 788                 goto out_free_props;
 789
 790         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 791                 client->name, dev_name(&client->dev));
 792
 793         return client;
 794
 795 out_free_props:
 796         if (info->properties)
 797                 device_remove_properties(&client->dev);
 798 out_err_put_of_node:
 799         of_node_put(info->of_node);
 800 out_err:
 801         dev_err(&adap->dev,
 802                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 803                 client->name, client->addr, status);
 804 out_err_silent:
 805         kfree(client);
 806         return NULL;
 807 }
 808 EXPORT_SYMBOL_GPL(i2c_new_device);
 809
 810
 811 /**
 812  * i2c_unregister_device - reverse effect of i2c_new_device()
 813  * @client: value returned from i2c_new_device()
 814  * Context: can sleep
 815  */
 816 void i2c_unregister_device(struct i2c_client *client)
 817 {
 818         if (!client)
 819                 return;
 820
 821         if (client->dev.of_node) {
 822                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 823                 of_node_put(client->dev.of_node);
 824         }
 825
 826         if (ACPI_COMPANION(&client->dev))
 827                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 828         device_unregister(&client->dev);
 829 }
 830 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 831
 832
 833 static const struct i2c_device_id dummy_id[] = {
 834         { "dummy", 0 },
 835         { },
 836 };
 837
 838 static int dummy_probe(struct i2c_client *client,
 839                        const struct i2c_device_id *id)
 840 {
 841         return 0;
 842 }
 843
 844 static int dummy_remove(struct i2c_client *client)
 845 {
 846         return 0;
 847 }
 848
 849 static struct i2c_driver dummy_driver = {
 850         .driver.name    = "dummy",
 851         .probe          = dummy_probe,
 852         .remove         = dummy_remove,
 853         .id_table       = dummy_id,
 854 };
 855
 856 /**
 857  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 858  * @adapter: the adapter managing the device
 859  * @address: seven bit address to be used
 860  * Context: can sleep
 861  *
 862  * This returns an I2C client bound to the "dummy" driver, intended for use
 863  * with devices that consume multiple addresses.  Examples of such chips
 864  * include various EEPROMS (like 24c04 and 24c08 models).
 865  *
 866  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 867  * except i2c_transfer() need a client handle; the dummy will be that handle.
 868  * And second, this prevents the specified address from being bound to a
 869  * different driver.
 870  *
 871  * This returns the new i2c client, which should be saved for later use with
 872  * i2c_unregister_device(); or NULL to indicate an error.
 873  */
 874 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 875 {
 876         struct i2c_board_info info = {
 877                 I2C_BOARD_INFO("dummy", address),
 878         };
 879
 880         return i2c_new_device(adapter, &info);
 881 }
 882 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 883
 884 /**
 885  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 886  * and create the associated device
 887  * @client: Handle to the primary client
 888  * @name: Handle to specify which secondary address to get
 889  * @default_addr: Used as a fallback if no secondary address was specified
 890  * Context: can sleep
 891  *
 892  * I2C clients can be composed of multiple I2C slaves bound together in a single
 893  * component. The I2C client driver then binds to the master I2C slave and needs
 894  * to create I2C dummy clients to communicate with all the other slaves.
 895  *
 896  * This function creates and returns an I2C dummy client whose I2C address is
 897  * retrieved from the platform firmware based on the given slave name. If no
 898  * address is specified by the firmware default_addr is used.
 899  *
 900  * On DT-based platforms the address is retrieved from the "reg" property entry
 901  * cell whose "reg-names" value matches the slave name.
 902  *
 903  * This returns the new i2c client, which should be saved for later use with
 904  * i2c_unregister_device(); or NULL to indicate an error.
 905  */
 906 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 907                                                 const char *name,
 908                                                 u16 default_addr)
 909 {
 910         struct device_node *np = client->dev.of_node;
 911         u32 addr = default_addr;
 912         int i;
 913
 914         if (np) {
 915                 i = of_property_match_string(np, "reg-names", name);
 916                 if (i >= 0)
 917                         of_property_read_u32_index(np, "reg", i, &addr);
 918         }
 919
 920         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 921         return i2c_new_dummy(client->adapter, addr);
 922 }
 923 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 924
 925 /* ------------------------------------------------------------------------- */
 926
 927 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 928
 929 static void i2c_adapter_dev_release(struct device *dev)
 930 {
 931         struct i2c_adapter *adap = to_i2c_adapter(dev);
 932         complete(&adap->dev_released);
 933 }
 934
 935 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 936 {
 937         unsigned int depth = 0;
 938
 939         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 940                 depth++;
 941
 942         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 943                   "adapter depth exceeds lockdep subclass limit\n");
 944
 945         return depth;
 946 }
 947 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 948
 949 /*
 950  * Let users instantiate I2C devices through sysfs. This can be used when
 951  * platform initialization code doesn't contain the proper data for
 952  * whatever reason. Also useful for drivers that do device detection and
 953  * detection fails, either because the device uses an unexpected address,
 954  * or this is a compatible device with different ID register values.
 955  *
 956  * Parameter checking may look overzealous, but we really don't want
 957  * the user to provide incorrect parameters.
 958  */
 959 static ssize_t
 960 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 961                      const char *buf, size_t count)
 962 {
 963         struct i2c_adapter *adap = to_i2c_adapter(dev);
 964         struct i2c_board_info info;
 965         struct i2c_client *client;
 966         char *blank, end;
 967         int res;
 968
 969         memset(&info, 0, sizeof(struct i2c_board_info));
 970
 971         blank = strchr(buf, ' ');
 972         if (!blank) {
 973                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 974                 return -EINVAL;
 975         }
 976         if (blank - buf > I2C_NAME_SIZE - 1) {
 977                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 978                 return -EINVAL;
 979         }
 980         memcpy(info.type, buf, blank - buf);
 981
 982         /* Parse remaining parameters, reject extra parameters */
 983         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 984         if (res < 1) {
 985                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 986                 return -EINVAL;
 987         }
 988         if (res > 1  && end != '\n') {
 989                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 990                 return -EINVAL;
 991         }
 992
 993         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 994                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 995                 info.flags |= I2C_CLIENT_TEN;
 996         }
 997
 998         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 999                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1000                 info.flags |= I2C_CLIENT_SLAVE;
1001         }
1002
1003         client = i2c_new_device(adap, &info);
1004         if (!client)
1005                 return -EINVAL;
1006
1007         /* Keep track of the added device */
1008         mutex_lock(&adap->userspace_clients_lock);
1009         list_add_tail(&client->detected, &adap->userspace_clients);
1010         mutex_unlock(&adap->userspace_clients_lock);
1011         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1012                  info.type, info.addr);
1013
1014         return count;
1015 }
1016 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1017
1018 /*
1019  * And of course let the users delete the devices they instantiated, if
1020  * they got it wrong. This interface can only be used to delete devices
1021  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1022  * don't delete devices to which some kernel code still has references.
1023  *
1024  * Parameter checking may look overzealous, but we really don't want
1025  * the user to delete the wrong device.
1026  */
1027 static ssize_t
1028 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1029                         const char *buf, size_t count)
1030 {
1031         struct i2c_adapter *adap = to_i2c_adapter(dev);
1032         struct i2c_client *client, *next;
1033         unsigned short addr;
1034         char end;
1035         int res;
1036
1037         /* Parse parameters, reject extra parameters */
1038         res = sscanf(buf, "%hi%c", &addr, &end);
1039         if (res < 1) {
1040                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1041                 return -EINVAL;
1042         }
1043         if (res > 1  && end != '\n') {
1044                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1045                 return -EINVAL;
1046         }
1047
1048         /* Make sure the device was added through sysfs */
1049         res = -ENOENT;
1050         mutex_lock_nested(&adap->userspace_clients_lock,
1051                           i2c_adapter_depth(adap));
1052         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1053                                  detected) {
1054                 if (i2c_encode_flags_to_addr(client) == addr) {
1055                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1056                                  "delete_device", client->name, client->addr);
1057
1058                         list_del(&client->detected);
1059                         i2c_unregister_device(client);
1060                         res = count;
1061                         break;
1062                 }
1063         }
1064         mutex_unlock(&adap->userspace_clients_lock);
1065
1066         if (res < 0)
1067                 dev_err(dev, "%s: Can't find device in list\n",
1068                         "delete_device");
1069         return res;
1070 }
1071 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1072                                    i2c_sysfs_delete_device);
1073
1074 static struct attribute *i2c_adapter_attrs[] = {
1075         &dev_attr_name.attr,
1076         &dev_attr_new_device.attr,
1077         &dev_attr_delete_device.attr,
1078         NULL
1079 };
1080 ATTRIBUTE_GROUPS(i2c_adapter);
1081
1082 struct device_type i2c_adapter_type = {
1083         .groups         = i2c_adapter_groups,
1084         .release        = i2c_adapter_dev_release,
1085 };
1086 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1087
1088 /**
1089  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1090  * @dev: device, probably from some driver model iterator
1091  *
1092  * When traversing the driver model tree, perhaps using driver model
1093  * iterators like @device_for_each_child(), you can't assume very much
1094  * about the nodes you find.  Use this function to avoid oopses caused
1095  * by wrongly treating some non-I2C device as an i2c_adapter.
1096  */
1097 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1098 {
1099         return (dev->type == &i2c_adapter_type)
1100                         ? to_i2c_adapter(dev)
1101                         : NULL;
1102 }
1103 EXPORT_SYMBOL(i2c_verify_adapter);
1104
1105 #ifdef CONFIG_I2C_COMPAT
1106 static struct class_compat *i2c_adapter_compat_class;
1107 #endif
1108
1109 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1110 {
1111         struct i2c_devinfo      *devinfo;
1112
1113         down_read(&__i2c_board_lock);
1114         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1115                 if (devinfo->busnum == adapter->nr
1116                                 && !i2c_new_device(adapter,
1117                                                 &devinfo->board_info))
1118                         dev_err(&adapter->dev,
1119                                 "Can't create device at 0x%02x\n",
1120                                 devinfo->board_info.addr);
1121         }
1122         up_read(&__i2c_board_lock);
1123 }
1124
1125 static int i2c_do_add_adapter(struct i2c_driver *driver,
1126                               struct i2c_adapter *adap)
1127 {
1128         /* Detect supported devices on that bus, and instantiate them */
1129         i2c_detect(adap, driver);
1130
1131         return 0;
1132 }
1133
1134 static int __process_new_adapter(struct device_driver *d, void *data)
1135 {
1136         return i2c_do_add_adapter(to_i2c_driver(d), data);
1137 }
1138
1139 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1140         .lock_bus =    i2c_adapter_lock_bus,
1141         .trylock_bus = i2c_adapter_trylock_bus,
1142         .unlock_bus =  i2c_adapter_unlock_bus,
1143 };
1144
1145 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1146 {
1147         struct irq_domain *domain = adap->host_notify_domain;
1148         irq_hw_number_t hwirq;
1149
1150         if (!domain)
1151                 return;
1152
1153         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1154                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1155
1156         irq_domain_remove(domain);
1157         adap->host_notify_domain = NULL;
1158 }
1159
1160 static int i2c_host_notify_irq_map(struct irq_domain *h,
1161                                           unsigned int virq,
1162                                           irq_hw_number_t hw_irq_num)
1163 {
1164         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1165
1166         return 0;
1167 }
1168
1169 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1170         .map = i2c_host_notify_irq_map,
1171 };
1172
1173 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1174 {
1175         struct irq_domain *domain;
1176
1177         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1178                 return 0;
1179
1180         domain = irq_domain_create_linear(adap->dev.fwnode,
1181                                           I2C_ADDR_7BITS_COUNT,
1182                                           &i2c_host_notify_irq_ops, adap);
1183         if (!domain)
1184                 return -ENOMEM;
1185
1186         adap->host_notify_domain = domain;
1187
1188         return 0;
1189 }
1190
1191 /**
1192  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1193  * I2C client.
1194  * @adap: the adapter
1195  * @addr: the I2C address of the notifying device
1196  * Context: can't sleep
1197  *
1198  * Helper function to be called from an I2C bus driver's interrupt
1199  * handler. It will schedule the Host Notify IRQ.
1200  */
1201 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1202 {
1203         int irq;
1204
1205         if (!adap)
1206                 return -EINVAL;
1207
1208         irq = irq_find_mapping(adap->host_notify_domain, addr);
1209         if (irq <= 0)
1210                 return -ENXIO;
1211
1212         generic_handle_irq(irq);
1213
1214         return 0;
1215 }
1216 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1217
1218 static int i2c_register_adapter(struct i2c_adapter *adap)
1219 {
1220         int res = -EINVAL;
1221
1222         /* Can't register until after driver model init */
1223         if (WARN_ON(!is_registered)) {
1224                 res = -EAGAIN;
1225                 goto out_list;
1226         }
1227
1228         /* Sanity checks */
1229         if (WARN(!adap->name[0], "i2c adapter has no name"))
1230                 goto out_list;
1231
1232         if (!adap->algo) {
1233                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1234                 goto out_list;
1235         }
1236
1237         if (!adap->lock_ops)
1238                 adap->lock_ops = &i2c_adapter_lock_ops;
1239
1240         adap->locked_flags = 0;
1241         rt_mutex_init(&adap->bus_lock);
1242         rt_mutex_init(&adap->mux_lock);
1243         mutex_init(&adap->userspace_clients_lock);
1244         INIT_LIST_HEAD(&adap->userspace_clients);
1245
1246         /* Set default timeout to 1 second if not already set */
1247         if (adap->timeout == 0)
1248                 adap->timeout = HZ;
1249
1250         /* register soft irqs for Host Notify */
1251         res = i2c_setup_host_notify_irq_domain(adap);
1252         if (res) {
1253                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1254                        adap->name, res);
1255                 goto out_list;
1256         }
1257
1258         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1259         adap->dev.bus = &i2c_bus_type;
1260         adap->dev.type = &i2c_adapter_type;
1261         res = device_register(&adap->dev);
1262         if (res) {
1263                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1264                 goto out_list;
1265         }
1266
1267         res = of_i2c_setup_smbus_alert(adap);
1268         if (res)
1269                 goto out_reg;
1270
1271         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1272
1273         pm_runtime_no_callbacks(&adap->dev);
1274         pm_suspend_ignore_children(&adap->dev, true);
1275         pm_runtime_enable(&adap->dev);
1276
1277 #ifdef CONFIG_I2C_COMPAT
1278         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1279                                        adap->dev.parent);
1280         if (res)
1281                 dev_warn(&adap->dev,
1282                          "Failed to create compatibility class link\n");
1283 #endif
1284
1285         i2c_init_recovery(adap);
1286
1287         /* create pre-declared device nodes */
1288         of_i2c_register_devices(adap);
1289         i2c_acpi_register_devices(adap);
1290         i2c_acpi_install_space_handler(adap);
1291
1292         if (adap->nr < __i2c_first_dynamic_bus_num)
1293                 i2c_scan_static_board_info(adap);
1294
1295         /* Notify drivers */
1296         mutex_lock(&core_lock);
1297         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1298         mutex_unlock(&core_lock);
1299
1300         return 0;
1301
1302 out_reg:
1303         init_completion(&adap->dev_released);
1304         device_unregister(&adap->dev);
1305         wait_for_completion(&adap->dev_released);
1306 out_list:
1307         mutex_lock(&core_lock);
1308         idr_remove(&i2c_adapter_idr, adap->nr);
1309         mutex_unlock(&core_lock);
1310         return res;
1311 }
1312
1313 /**
1314  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1315  * @adap: the adapter to register (with adap->nr initialized)
1316  * Context: can sleep
1317  *
1318  * See i2c_add_numbered_adapter() for details.
1319  */
1320 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1321 {
1322         int id;
1323
1324         mutex_lock(&core_lock);
1325         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1326         mutex_unlock(&core_lock);
1327         if (WARN(id < 0, "couldn't get idr"))
1328                 return id == -ENOSPC ? -EBUSY : id;
1329
1330         return i2c_register_adapter(adap);
1331 }
1332
1333 /**
1334  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1335  * @adapter: the adapter to add
1336  * Context: can sleep
1337  *
1338  * This routine is used to declare an I2C adapter when its bus number
1339  * doesn't matter or when its bus number is specified by an dt alias.
1340  * Examples of bases when the bus number doesn't matter: I2C adapters
1341  * dynamically added by USB links or PCI plugin cards.
1342  *
1343  * When this returns zero, a new bus number was allocated and stored
1344  * in adap->nr, and the specified adapter became available for clients.
1345  * Otherwise, a negative errno value is returned.
1346  */
1347 int i2c_add_adapter(struct i2c_adapter *adapter)
1348 {
1349         struct device *dev = &adapter->dev;
1350         int id;
1351
1352         if (dev->of_node) {
1353                 id = of_alias_get_id(dev->of_node, "i2c");
1354                 if (id >= 0) {
1355                         adapter->nr = id;
1356                         return __i2c_add_numbered_adapter(adapter);
1357                 }
1358         }
1359
1360         mutex_lock(&core_lock);
1361         id = idr_alloc(&i2c_adapter_idr, adapter,
1362                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1363         mutex_unlock(&core_lock);
1364         if (WARN(id < 0, "couldn't get idr"))
1365                 return id;
1366
1367         adapter->nr = id;
1368
1369         return i2c_register_adapter(adapter);
1370 }
1371 EXPORT_SYMBOL(i2c_add_adapter);
1372
1373 /**
1374  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1375  * @adap: the adapter to register (with adap->nr initialized)
1376  * Context: can sleep
1377  *
1378  * This routine is used to declare an I2C adapter when its bus number
1379  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1380  * or otherwise built in to the system's mainboard, and where i2c_board_info
1381  * is used to properly configure I2C devices.
1382  *
1383  * If the requested bus number is set to -1, then this function will behave
1384  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1385  *
1386  * If no devices have pre-been declared for this bus, then be sure to
1387  * register the adapter before any dynamically allocated ones.  Otherwise
1388  * the required bus ID may not be available.
1389  *
1390  * When this returns zero, the specified adapter became available for
1391  * clients using the bus number provided in adap->nr.  Also, the table
1392  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1393  * and the appropriate driver model device nodes are created.  Otherwise, a
1394  * negative errno value is returned.
1395  */
1396 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1397 {
1398         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1399                 return i2c_add_adapter(adap);
1400
1401         return __i2c_add_numbered_adapter(adap);
1402 }
1403 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1404
1405 static void i2c_do_del_adapter(struct i2c_driver *driver,
1406                               struct i2c_adapter *adapter)
1407 {
1408         struct i2c_client *client, *_n;
1409
1410         /* Remove the devices we created ourselves as the result of hardware
1411          * probing (using a driver's detect method) */
1412         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1413                 if (client->adapter == adapter) {
1414                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1415                                 client->name, client->addr);
1416                         list_del(&client->detected);
1417                         i2c_unregister_device(client);
1418                 }
1419         }
1420 }
1421
1422 static int __unregister_client(struct device *dev, void *dummy)
1423 {
1424         struct i2c_client *client = i2c_verify_client(dev);
1425         if (client && strcmp(client->name, "dummy"))
1426                 i2c_unregister_device(client);
1427         return 0;
1428 }
1429
1430 static int __unregister_dummy(struct device *dev, void *dummy)
1431 {
1432         struct i2c_client *client = i2c_verify_client(dev);
1433         i2c_unregister_device(client);
1434         return 0;
1435 }
1436
1437 static int __process_removed_adapter(struct device_driver *d, void *data)
1438 {
1439         i2c_do_del_adapter(to_i2c_driver(d), data);
1440         return 0;
1441 }
1442
1443 /**
1444  * i2c_del_adapter - unregister I2C adapter
1445  * @adap: the adapter being unregistered
1446  * Context: can sleep
1447  *
1448  * This unregisters an I2C adapter which was previously registered
1449  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1450  */
1451 void i2c_del_adapter(struct i2c_adapter *adap)
1452 {
1453         struct i2c_adapter *found;
1454         struct i2c_client *client, *next;
1455
1456         /* First make sure that this adapter was ever added */
1457         mutex_lock(&core_lock);
1458         found = idr_find(&i2c_adapter_idr, adap->nr);
1459         mutex_unlock(&core_lock);
1460         if (found != adap) {
1461                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1462                 return;
1463         }
1464
1465         i2c_acpi_remove_space_handler(adap);
1466         /* Tell drivers about this removal */
1467         mutex_lock(&core_lock);
1468         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1469                                __process_removed_adapter);
1470         mutex_unlock(&core_lock);
1471
1472         /* Remove devices instantiated from sysfs */
1473         mutex_lock_nested(&adap->userspace_clients_lock,
1474                           i2c_adapter_depth(adap));
1475         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1476                                  detected) {
1477                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1478                         client->addr);
1479                 list_del(&client->detected);
1480                 i2c_unregister_device(client);
1481         }
1482         mutex_unlock(&adap->userspace_clients_lock);
1483
1484         /* Detach any active clients. This can't fail, thus we do not
1485          * check the returned value. This is a two-pass process, because
1486          * we can't remove the dummy devices during the first pass: they
1487          * could have been instantiated by real devices wishing to clean
1488          * them up properly, so we give them a chance to do that first. */
1489         device_for_each_child(&adap->dev, NULL, __unregister_client);
1490         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1491
1492 #ifdef CONFIG_I2C_COMPAT
1493         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1494                                  adap->dev.parent);
1495 #endif
1496
1497         /* device name is gone after device_unregister */
1498         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1499
1500         pm_runtime_disable(&adap->dev);
1501
1502         i2c_host_notify_irq_teardown(adap);
1503
1504         /* wait until all references to the device are gone
1505          *
1506          * FIXME: This is old code and should ideally be replaced by an
1507          * alternative which results in decoupling the lifetime of the struct
1508          * device from the i2c_adapter, like spi or netdev do. Any solution
1509          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1510          */
1511         init_completion(&adap->dev_released);
1512         device_unregister(&adap->dev);
1513         wait_for_completion(&adap->dev_released);
1514
1515         /* free bus id */
1516         mutex_lock(&core_lock);
1517         idr_remove(&i2c_adapter_idr, adap->nr);
1518         mutex_unlock(&core_lock);
1519
1520         /* Clear the device structure in case this adapter is ever going to be
1521            added again */
1522         memset(&adap->dev, 0, sizeof(adap->dev));
1523 }
1524 EXPORT_SYMBOL(i2c_del_adapter);
1525
1526 /**
1527  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1528  * @dev: The device to scan for I2C timing properties
1529  * @t: the i2c_timings struct to be filled with values
1530  * @use_defaults: bool to use sane defaults derived from the I2C specification
1531  *                when properties are not found, otherwise use 0
1532  *
1533  * Scan the device for the generic I2C properties describing timing parameters
1534  * for the signal and fill the given struct with the results. If a property was
1535  * not found and use_defaults was true, then maximum timings are assumed which
1536  * are derived from the I2C specification. If use_defaults is not used, the
1537  * results will be 0, so drivers can apply their own defaults later. The latter
1538  * is mainly intended for avoiding regressions of existing drivers which want
1539  * to switch to this function. New drivers almost always should use the defaults.
1540  */
1541
1542 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1543 {
1544         int ret;
1545
1546         memset(t, 0, sizeof(*t));
1547
1548         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1549         if (ret && use_defaults)
1550                 t->bus_freq_hz = 100000;
1551
1552         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1553         if (ret && use_defaults) {
1554                 if (t->bus_freq_hz <= 100000)
1555                         t->scl_rise_ns = 1000;
1556                 else if (t->bus_freq_hz <= 400000)
1557                         t->scl_rise_ns = 300;
1558                 else
1559                         t->scl_rise_ns = 120;
1560         }
1561
1562         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1563         if (ret && use_defaults) {
1564                 if (t->bus_freq_hz <= 400000)
1565                         t->scl_fall_ns = 300;
1566                 else
1567                         t->scl_fall_ns = 120;
1568         }
1569
1570         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1571
1572         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1573         if (ret && use_defaults)
1574                 t->sda_fall_ns = t->scl_fall_ns;
1575
1576         device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1577 }
1578 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1579
1580 /* ------------------------------------------------------------------------- */
1581
1582 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1583 {
1584         int res;
1585
1586         mutex_lock(&core_lock);
1587         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1588         mutex_unlock(&core_lock);
1589
1590         return res;
1591 }
1592 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1593
1594 static int __process_new_driver(struct device *dev, void *data)
1595 {
1596         if (dev->type != &i2c_adapter_type)
1597                 return 0;
1598         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1599 }
1600
1601 /*
1602  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1603  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1604  */
1605
1606 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1607 {
1608         int res;
1609
1610         /* Can't register until after driver model init */
1611         if (WARN_ON(!is_registered))
1612                 return -EAGAIN;
1613
1614         /* add the driver to the list of i2c drivers in the driver core */
1615         driver->driver.owner = owner;
1616         driver->driver.bus = &i2c_bus_type;
1617         INIT_LIST_HEAD(&driver->clients);
1618
1619         /* When registration returns, the driver core
1620          * will have called probe() for all matching-but-unbound devices.
1621          */
1622         res = driver_register(&driver->driver);
1623         if (res)
1624                 return res;
1625
1626         pr_debug("driver [%s] registered\n", driver->driver.name);
1627
1628         /* Walk the adapters that are already present */
1629         i2c_for_each_dev(driver, __process_new_driver);
1630
1631         return 0;
1632 }
1633 EXPORT_SYMBOL(i2c_register_driver);
1634
1635 static int __process_removed_driver(struct device *dev, void *data)
1636 {
1637         if (dev->type == &i2c_adapter_type)
1638                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1639         return 0;
1640 }
1641
1642 /**
1643  * i2c_del_driver - unregister I2C driver
1644  * @driver: the driver being unregistered
1645  * Context: can sleep
1646  */
1647 void i2c_del_driver(struct i2c_driver *driver)
1648 {
1649         i2c_for_each_dev(driver, __process_removed_driver);
1650
1651         driver_unregister(&driver->driver);
1652         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1653 }
1654 EXPORT_SYMBOL(i2c_del_driver);
1655
1656 /* ------------------------------------------------------------------------- */
1657
1658 /**
1659  * i2c_use_client - increments the reference count of the i2c client structure
1660  * @client: the client being referenced
1661  *
1662  * Each live reference to a client should be refcounted. The driver model does
1663  * that automatically as part of driver binding, so that most drivers don't
1664  * need to do this explicitly: they hold a reference until they're unbound
1665  * from the device.
1666  *
1667  * A pointer to the client with the incremented reference counter is returned.
1668  */
1669 struct i2c_client *i2c_use_client(struct i2c_client *client)
1670 {
1671         if (client && get_device(&client->dev))
1672                 return client;
1673         return NULL;
1674 }
1675 EXPORT_SYMBOL(i2c_use_client);
1676
1677 /**
1678  * i2c_release_client - release a use of the i2c client structure
1679  * @client: the client being no longer referenced
1680  *
1681  * Must be called when a user of a client is finished with it.
1682  */
1683 void i2c_release_client(struct i2c_client *client)
1684 {
1685         if (client)
1686                 put_device(&client->dev);
1687 }
1688 EXPORT_SYMBOL(i2c_release_client);
1689
1690 struct i2c_cmd_arg {
1691         unsigned        cmd;
1692         void            *arg;
1693 };
1694
1695 static int i2c_cmd(struct device *dev, void *_arg)
1696 {
1697         struct i2c_client       *client = i2c_verify_client(dev);
1698         struct i2c_cmd_arg      *arg = _arg;
1699         struct i2c_driver       *driver;
1700
1701         if (!client || !client->dev.driver)
1702                 return 0;
1703
1704         driver = to_i2c_driver(client->dev.driver);
1705         if (driver->command)
1706                 driver->command(client, arg->cmd, arg->arg);
1707         return 0;
1708 }
1709
1710 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1711 {
1712         struct i2c_cmd_arg      cmd_arg;
1713
1714         cmd_arg.cmd = cmd;
1715         cmd_arg.arg = arg;
1716         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1717 }
1718 EXPORT_SYMBOL(i2c_clients_command);
1719
1720 static int __init i2c_init(void)
1721 {
1722         int retval;
1723
1724         retval = of_alias_get_highest_id("i2c");
1725
1726         down_write(&__i2c_board_lock);
1727         if (retval >= __i2c_first_dynamic_bus_num)
1728                 __i2c_first_dynamic_bus_num = retval + 1;
1729         up_write(&__i2c_board_lock);
1730
1731         retval = bus_register(&i2c_bus_type);
1732         if (retval)
1733                 return retval;
1734
1735         is_registered = true;
1736
1737 #ifdef CONFIG_I2C_COMPAT
1738         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1739         if (!i2c_adapter_compat_class) {
1740                 retval = -ENOMEM;
1741                 goto bus_err;
1742         }
1743 #endif
1744         retval = i2c_add_driver(&dummy_driver);
1745         if (retval)
1746                 goto class_err;
1747
1748         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1749                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1750         if (IS_ENABLED(CONFIG_ACPI))
1751                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1752
1753         return 0;
1754
1755 class_err:
1756 #ifdef CONFIG_I2C_COMPAT
1757         class_compat_unregister(i2c_adapter_compat_class);
1758 bus_err:
1759 #endif
1760         is_registered = false;
1761         bus_unregister(&i2c_bus_type);
1762         return retval;
1763 }
1764
1765 static void __exit i2c_exit(void)
1766 {
1767         if (IS_ENABLED(CONFIG_ACPI))
1768                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1769         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1770                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1771         i2c_del_driver(&dummy_driver);
1772 #ifdef CONFIG_I2C_COMPAT
1773         class_compat_unregister(i2c_adapter_compat_class);
1774 #endif
1775         bus_unregister(&i2c_bus_type);
1776         tracepoint_synchronize_unregister();
1777 }
1778
1779 /* We must initialize early, because some subsystems register i2c drivers
1780  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1781  */
1782 postcore_initcall(i2c_init);
1783 module_exit(i2c_exit);
1784
1785 /* ----------------------------------------------------
1786  * the functional interface to the i2c busses.
1787  * ----------------------------------------------------
1788  */
1789
1790 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1791 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1792
1793 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1794 {
1795         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1796                             err_msg, msg->addr, msg->len,
1797                             msg->flags & I2C_M_RD ? "read" : "write");
1798         return -EOPNOTSUPP;
1799 }
1800
1801 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1802 {
1803         const struct i2c_adapter_quirks *q = adap->quirks;
1804         int max_num = q->max_num_msgs, i;
1805         bool do_len_check = true;
1806
1807         if (q->flags & I2C_AQ_COMB) {
1808                 max_num = 2;
1809
1810                 /* special checks for combined messages */
1811                 if (num == 2) {
1812                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1813                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1814
1815                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1816                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1817
1818                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1819                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1820
1821                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1822                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1823
1824                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1825                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1826
1827                         do_len_check = false;
1828                 }
1829         }
1830
1831         if (i2c_quirk_exceeded(num, max_num))
1832                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1833
1834         for (i = 0; i < num; i++) {
1835                 u16 len = msgs[i].len;
1836
1837                 if (msgs[i].flags & I2C_M_RD) {
1838                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1839                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1840
1841                         if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1842                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1843                 } else {
1844                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1845                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1846
1847                         if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1848                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1849                 }
1850         }
1851
1852         return 0;
1853 }
1854
1855 /**
1856  * __i2c_transfer - unlocked flavor of i2c_transfer
1857  * @adap: Handle to I2C bus
1858  * @msgs: One or more messages to execute before STOP is issued to
1859  *      terminate the operation; each message begins with a START.
1860  * @num: Number of messages to be executed.
1861  *
1862  * Returns negative errno, else the number of messages executed.
1863  *
1864  * Adapter lock must be held when calling this function. No debug logging
1865  * takes place. adap->algo->master_xfer existence isn't checked.
1866  */
1867 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1868 {
1869         unsigned long orig_jiffies;
1870         int ret, try;
1871
1872         if (WARN_ON(!msgs || num < 1))
1873                 return -EINVAL;
1874
1875         ret = __i2c_check_suspended(adap);
1876         if (ret)
1877                 return ret;
1878
1879         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1880                 return -EOPNOTSUPP;
1881
1882         /*
1883          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1884          * enabled.  This is an efficient way of keeping the for-loop from
1885          * being executed when not needed.
1886          */
1887         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1888                 int i;
1889                 for (i = 0; i < num; i++)
1890                         if (msgs[i].flags & I2C_M_RD)
1891                                 trace_i2c_read(adap, &msgs[i], i);
1892                         else
1893                                 trace_i2c_write(adap, &msgs[i], i);
1894         }
1895
1896         /* Retry automatically on arbitration loss */
1897         orig_jiffies = jiffies;
1898         for (ret = 0, try = 0; try <= adap->retries; try++) {
1899                 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
1900                         ret = adap->algo->master_xfer_atomic(adap, msgs, num);
1901                 else
1902                         ret = adap->algo->master_xfer(adap, msgs, num);
1903
1904                 if (ret != -EAGAIN)
1905                         break;
1906                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1907                         break;
1908         }
1909
1910         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1911                 int i;
1912                 for (i = 0; i < ret; i++)
1913                         if (msgs[i].flags & I2C_M_RD)
1914                                 trace_i2c_reply(adap, &msgs[i], i);
1915                 trace_i2c_result(adap, num, ret);
1916         }
1917
1918         return ret;
1919 }
1920 EXPORT_SYMBOL(__i2c_transfer);
1921
1922 /**
1923  * i2c_transfer - execute a single or combined I2C message
1924  * @adap: Handle to I2C bus
1925  * @msgs: One or more messages to execute before STOP is issued to
1926  *      terminate the operation; each message begins with a START.
1927  * @num: Number of messages to be executed.
1928  *
1929  * Returns negative errno, else the number of messages executed.
1930  *
1931  * Note that there is no requirement that each message be sent to
1932  * the same slave address, although that is the most common model.
1933  */
1934 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1935 {
1936         int ret;
1937
1938         if (!adap->algo->master_xfer) {
1939                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1940                 return -EOPNOTSUPP;
1941         }
1942
1943         /* REVISIT the fault reporting model here is weak:
1944          *
1945          *  - When we get an error after receiving N bytes from a slave,
1946          *    there is no way to report "N".
1947          *
1948          *  - When we get a NAK after transmitting N bytes to a slave,
1949          *    there is no way to report "N" ... or to let the master
1950          *    continue executing the rest of this combined message, if
1951          *    that's the appropriate response.
1952          *
1953          *  - When for example "num" is two and we successfully complete
1954          *    the first message but get an error part way through the
1955          *    second, it's unclear whether that should be reported as
1956          *    one (discarding status on the second message) or errno
1957          *    (discarding status on the first one).
1958          */
1959         ret = __i2c_lock_bus_helper(adap);
1960         if (ret)
1961                 return ret;
1962
1963         ret = __i2c_transfer(adap, msgs, num);
1964         i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1965
1966         return ret;
1967 }
1968 EXPORT_SYMBOL(i2c_transfer);
1969
1970 /**
1971  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1972  *                             to/from a buffer
1973  * @client: Handle to slave device
1974  * @buf: Where the data is stored
1975  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1976  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1977  *
1978  * Returns negative errno, or else the number of bytes transferred.
1979  */
1980 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1981                               int count, u16 flags)
1982 {
1983         int ret;
1984         struct i2c_msg msg = {
1985                 .addr = client->addr,
1986                 .flags = flags | (client->flags & I2C_M_TEN),
1987                 .len = count,
1988                 .buf = buf,
1989         };
1990
1991         ret = i2c_transfer(client->adapter, &msg, 1);
1992
1993         /*
1994          * If everything went ok (i.e. 1 msg transferred), return #bytes
1995          * transferred, else error code.
1996          */
1997         return (ret == 1) ? count : ret;
1998 }
1999 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2000
2001 /**
2002  * i2c_get_device_id - get manufacturer, part id and die revision of a device
2003  * @client: The device to query
2004  * @id: The queried information
2005  *
2006  * Returns negative errno on error, zero on success.
2007  */
2008 int i2c_get_device_id(const struct i2c_client *client,
2009                       struct i2c_device_identity *id)
2010 {
2011         struct i2c_adapter *adap = client->adapter;
2012         union i2c_smbus_data raw_id;
2013         int ret;
2014
2015         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2016                 return -EOPNOTSUPP;
2017
2018         raw_id.block[0] = 3;
2019         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2020                              I2C_SMBUS_READ, client->addr << 1,
2021                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2022         if (ret)
2023                 return ret;
2024
2025         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2026         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2027         id->die_revision = raw_id.block[3] & 0x7;
2028         return 0;
2029 }
2030 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2031
2032 /* ----------------------------------------------------
2033  * the i2c address scanning function
2034  * Will not work for 10-bit addresses!
2035  * ----------------------------------------------------
2036  */
2037
2038 /*
2039  * Legacy default probe function, mostly relevant for SMBus. The default
2040  * probe method is a quick write, but it is known to corrupt the 24RF08
2041  * EEPROMs due to a state machine bug, and could also irreversibly
2042  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2043  * we use a short byte read instead. Also, some bus drivers don't implement
2044  * quick write, so we fallback to a byte read in that case too.
2045  * On x86, there is another special case for FSC hardware monitoring chips,
2046  * which want regular byte reads (address 0x73.) Fortunately, these are the
2047  * only known chips using this I2C address on PC hardware.
2048  * Returns 1 if probe succeeded, 0 if not.
2049  */
2050 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2051 {
2052         int err;
2053         union i2c_smbus_data dummy;
2054
2055 #ifdef CONFIG_X86
2056         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2057          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2058                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2059                                      I2C_SMBUS_BYTE_DATA, &dummy);
2060         else
2061 #endif
2062         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2063          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2064                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2065                                      I2C_SMBUS_QUICK, NULL);
2066         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2067                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2068                                      I2C_SMBUS_BYTE, &dummy);
2069         else {
2070                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2071                          addr);
2072                 err = -EOPNOTSUPP;
2073         }
2074
2075         return err >= 0;
2076 }
2077
2078 static int i2c_detect_address(struct i2c_client *temp_client,
2079                               struct i2c_driver *driver)
2080 {
2081         struct i2c_board_info info;
2082         struct i2c_adapter *adapter = temp_client->adapter;
2083         int addr = temp_client->addr;
2084         int err;
2085
2086         /* Make sure the address is valid */
2087         err = i2c_check_7bit_addr_validity_strict(addr);
2088         if (err) {
2089                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2090                          addr);
2091                 return err;
2092         }
2093
2094         /* Skip if already in use (7 bit, no need to encode flags) */
2095         if (i2c_check_addr_busy(adapter, addr))
2096                 return 0;
2097
2098         /* Make sure there is something at this address */
2099         if (!i2c_default_probe(adapter, addr))
2100                 return 0;
2101
2102         /* Finally call the custom detection function */
2103         memset(&info, 0, sizeof(struct i2c_board_info));
2104         info.addr = addr;
2105         err = driver->detect(temp_client, &info);
2106         if (err) {
2107                 /* -ENODEV is returned if the detection fails. We catch it
2108                    here as this isn't an error. */
2109                 return err == -ENODEV ? 0 : err;
2110         }
2111
2112         /* Consistency check */
2113         if (info.type[0] == '\0') {
2114                 dev_err(&adapter->dev,
2115                         "%s detection function provided no name for 0x%x\n",
2116                         driver->driver.name, addr);
2117         } else {
2118                 struct i2c_client *client;
2119
2120                 /* Detection succeeded, instantiate the device */
2121                 if (adapter->class & I2C_CLASS_DEPRECATED)
2122                         dev_warn(&adapter->dev,
2123                                 "This adapter will soon drop class based instantiation of devices. "
2124                                 "Please make sure client 0x%02x gets instantiated by other means. "
2125                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2126                                 info.addr);
2127
2128                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2129                         info.type, info.addr);
2130                 client = i2c_new_device(adapter, &info);
2131                 if (client)
2132                         list_add_tail(&client->detected, &driver->clients);
2133                 else
2134                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2135                                 info.type, info.addr);
2136         }
2137         return 0;
2138 }
2139
2140 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2141 {
2142         const unsigned short *address_list;
2143         struct i2c_client *temp_client;
2144         int i, err = 0;
2145         int adap_id = i2c_adapter_id(adapter);
2146
2147         address_list = driver->address_list;
2148         if (!driver->detect || !address_list)
2149                 return 0;
2150
2151         /* Warn that the adapter lost class based instantiation */
2152         if (adapter->class == I2C_CLASS_DEPRECATED) {
2153                 dev_dbg(&adapter->dev,
2154                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2155                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2156                         driver->driver.name);
2157                 return 0;
2158         }
2159
2160         /* Stop here if the classes do not match */
2161         if (!(adapter->class & driver->class))
2162                 return 0;
2163
2164         /* Set up a temporary client to help detect callback */
2165         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2166         if (!temp_client)
2167                 return -ENOMEM;
2168         temp_client->adapter = adapter;
2169
2170         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2171                 dev_dbg(&adapter->dev,
2172                         "found normal entry for adapter %d, addr 0x%02x\n",
2173                         adap_id, address_list[i]);
2174                 temp_client->addr = address_list[i];
2175                 err = i2c_detect_address(temp_client, driver);
2176                 if (unlikely(err))
2177                         break;
2178         }
2179
2180         kfree(temp_client);
2181         return err;
2182 }
2183
2184 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2185 {
2186         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2187                               I2C_SMBUS_QUICK, NULL) >= 0;
2188 }
2189 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2190
2191 struct i2c_client *
2192 i2c_new_probed_device(struct i2c_adapter *adap,
2193                       struct i2c_board_info *info,
2194                       unsigned short const *addr_list,
2195                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2196 {
2197         int i;
2198
2199         if (!probe)
2200                 probe = i2c_default_probe;
2201
2202         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2203                 /* Check address validity */
2204                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2205                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2206                                  addr_list[i]);
2207                         continue;
2208                 }
2209
2210                 /* Check address availability (7 bit, no need to encode flags) */
2211                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2212                         dev_dbg(&adap->dev,
2213                                 "Address 0x%02x already in use, not probing\n",
2214                                 addr_list[i]);
2215                         continue;
2216                 }
2217
2218                 /* Test address responsiveness */
2219                 if (probe(adap, addr_list[i]))
2220                         break;
2221         }
2222
2223         if (addr_list[i] == I2C_CLIENT_END) {
2224                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2225                 return NULL;
2226         }
2227
2228         info->addr = addr_list[i];
2229         return i2c_new_device(adap, info);
2230 }
2231 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2232
2233 struct i2c_adapter *i2c_get_adapter(int nr)
2234 {
2235         struct i2c_adapter *adapter;
2236
2237         mutex_lock(&core_lock);
2238         adapter = idr_find(&i2c_adapter_idr, nr);
2239         if (!adapter)
2240                 goto exit;
2241
2242         if (try_module_get(adapter->owner))
2243                 get_device(&adapter->dev);
2244         else
2245                 adapter = NULL;
2246
2247  exit:
2248         mutex_unlock(&core_lock);
2249         return adapter;
2250 }
2251 EXPORT_SYMBOL(i2c_get_adapter);
2252
2253 void i2c_put_adapter(struct i2c_adapter *adap)
2254 {
2255         if (!adap)
2256                 return;
2257
2258         put_device(&adap->dev);
2259         module_put(adap->owner);
2260 }
2261 EXPORT_SYMBOL(i2c_put_adapter);
2262
2263 /**
2264  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2265  * @msg: the message to be checked
2266  * @threshold: the minimum number of bytes for which using DMA makes sense.
2267  *             Should at least be 1.
2268  *
2269  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2270  *         Or a valid pointer to be used with DMA. After use, release it by
2271  *         calling i2c_put_dma_safe_msg_buf().
2272  *
2273  * This function must only be called from process context!
2274  */
2275 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2276 {
2277         /* also skip 0-length msgs for bogus thresholds of 0 */
2278         if (!threshold)
2279                 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2280                          msg->addr);
2281         if (msg->len < threshold || msg->len == 0)
2282                 return NULL;
2283
2284         if (msg->flags & I2C_M_DMA_SAFE)
2285                 return msg->buf;
2286
2287         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2288                  msg->addr, msg->len);
2289
2290         if (msg->flags & I2C_M_RD)
2291                 return kzalloc(msg->len, GFP_KERNEL);
2292         else
2293                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2294 }
2295 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2296
2297 /**
2298  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2299  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2300  * @msg: the message which the buffer corresponds to
2301  * @xferred: bool saying if the message was transferred
2302  */
2303 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2304 {
2305         if (!buf || buf == msg->buf)
2306                 return;
2307
2308         if (xferred && msg->flags & I2C_M_RD)
2309                 memcpy(msg->buf, buf, msg->len);
2310
2311         kfree(buf);
2312 }
2313 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2314
2315 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2316 MODULE_DESCRIPTION("I2C-Bus main module");
2317 MODULE_LICENSE("GPL");