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.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 /*
  62  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  63  * deletion of detected devices, and attach_adapter calls are serialized
  64  */
  65 static DEFINE_MUTEX(core_lock);
  66 static DEFINE_IDR(i2c_adapter_idr);
  67
  68 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  69
  70 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
  71 static bool is_registered;
  72
  73 int i2c_transfer_trace_reg(void)
  74 {
  75         static_key_slow_inc(&i2c_trace_msg);
  76         return 0;
  77 }
  78
  79 void i2c_transfer_trace_unreg(void)
  80 {
  81         static_key_slow_dec(&i2c_trace_msg);
  82 }
  83
  84 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  85                                                 const struct i2c_client *client)
  86 {
  87         if (!(id && client))
  88                 return NULL;
  89
  90         while (id->name[0]) {
  91                 if (strcmp(client->name, id->name) == 0)
  92                         return id;
  93                 id++;
  94         }
  95         return NULL;
  96 }
  97 EXPORT_SYMBOL_GPL(i2c_match_id);
  98
  99 static int i2c_device_match(struct device *dev, struct device_driver *drv)
 100 {
 101         struct i2c_client       *client = i2c_verify_client(dev);
 102         struct i2c_driver       *driver;
 103
 104
 105         /* Attempt an OF style match */
 106         if (i2c_of_match_device(drv->of_match_table, client))
 107                 return 1;
 108
 109         /* Then ACPI style match */
 110         if (acpi_driver_match_device(dev, drv))
 111                 return 1;
 112
 113         driver = to_i2c_driver(drv);
 114
 115         /* Finally an I2C match */
 116         if (i2c_match_id(driver->id_table, client))
 117                 return 1;
 118
 119         return 0;
 120 }
 121
 122 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 123 {
 124         struct i2c_client *client = to_i2c_client(dev);
 125         int rc;
 126
 127         rc = acpi_device_uevent_modalias(dev, env);
 128         if (rc != -ENODEV)
 129                 return rc;
 130
 131         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 132 }
 133
 134 /* i2c bus recovery routines */
 135 static int get_scl_gpio_value(struct i2c_adapter *adap)
 136 {
 137         return gpio_get_value(adap->bus_recovery_info->scl_gpio);
 138 }
 139
 140 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 141 {
 142         gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
 143 }
 144
 145 static int get_sda_gpio_value(struct i2c_adapter *adap)
 146 {
 147         return gpio_get_value(adap->bus_recovery_info->sda_gpio);
 148 }
 149
 150 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
 151 {
 152         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 153         struct device *dev = &adap->dev;
 154         int ret = 0;
 155
 156         ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
 157                         GPIOF_OUT_INIT_HIGH, "i2c-scl");
 158         if (ret) {
 159                 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
 160                 return ret;
 161         }
 162
 163         if (bri->get_sda) {
 164                 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
 165                         /* work without SDA polling */
 166                         dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
 167                                         bri->sda_gpio);
 168                         bri->get_sda = NULL;
 169                 }
 170         }
 171
 172         return ret;
 173 }
 174
 175 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
 176 {
 177         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 178
 179         if (bri->get_sda)
 180                 gpio_free(bri->sda_gpio);
 181
 182         gpio_free(bri->scl_gpio);
 183 }
 184
 185 /*
 186  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 187  * We will generate clock with rate 100 KHz and so duration of both clock levels
 188  * is: delay in ns = (10^6 / 100) / 2
 189  */
 190 #define RECOVERY_NDELAY         5000
 191 #define RECOVERY_CLK_CNT        9
 192
 193 static int i2c_generic_recovery(struct i2c_adapter *adap)
 194 {
 195         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 196         int i = 0, val = 1, ret = 0;
 197
 198         if (bri->prepare_recovery)
 199                 bri->prepare_recovery(adap);
 200
 201         bri->set_scl(adap, val);
 202         ndelay(RECOVERY_NDELAY);
 203
 204         /*
 205          * By this time SCL is high, as we need to give 9 falling-rising edges
 206          */
 207         while (i++ < RECOVERY_CLK_CNT * 2) {
 208                 if (val) {
 209                         /* SCL shouldn't be low here */
 210                         if (!bri->get_scl(adap)) {
 211                                 dev_err(&adap->dev,
 212                                         "SCL is stuck low, exit recovery\n");
 213                                 ret = -EBUSY;
 214                                 break;
 215                         }
 216                         /* Break if SDA is high */
 217                         if (bri->get_sda && bri->get_sda(adap))
 218                                 break;
 219                 }
 220
 221                 val = !val;
 222                 bri->set_scl(adap, val);
 223                 ndelay(RECOVERY_NDELAY);
 224         }
 225
 226         /* check if recovery actually succeeded */
 227         if (bri->get_sda && !bri->get_sda(adap))
 228                 ret = -EBUSY;
 229
 230         if (bri->unprepare_recovery)
 231                 bri->unprepare_recovery(adap);
 232
 233         return ret;
 234 }
 235
 236 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 237 {
 238         return i2c_generic_recovery(adap);
 239 }
 240 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 241
 242 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
 243 {
 244         int ret;
 245
 246         ret = i2c_get_gpios_for_recovery(adap);
 247         if (ret)
 248                 return ret;
 249
 250         ret = i2c_generic_recovery(adap);
 251         i2c_put_gpios_for_recovery(adap);
 252
 253         return ret;
 254 }
 255 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
 256
 257 int i2c_recover_bus(struct i2c_adapter *adap)
 258 {
 259         if (!adap->bus_recovery_info)
 260                 return -EOPNOTSUPP;
 261
 262         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 263         return adap->bus_recovery_info->recover_bus(adap);
 264 }
 265 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 266
 267 static void i2c_init_recovery(struct i2c_adapter *adap)
 268 {
 269         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 270         char *err_str;
 271
 272         if (!bri)
 273                 return;
 274
 275         if (!bri->recover_bus) {
 276                 err_str = "no recover_bus() found";
 277                 goto err;
 278         }
 279
 280         /* Generic GPIO recovery */
 281         if (bri->recover_bus == i2c_generic_gpio_recovery) {
 282                 if (!gpio_is_valid(bri->scl_gpio)) {
 283                         err_str = "invalid SCL gpio";
 284                         goto err;
 285                 }
 286
 287                 if (gpio_is_valid(bri->sda_gpio))
 288                         bri->get_sda = get_sda_gpio_value;
 289                 else
 290                         bri->get_sda = NULL;
 291
 292                 bri->get_scl = get_scl_gpio_value;
 293                 bri->set_scl = set_scl_gpio_value;
 294         } else if (bri->recover_bus == i2c_generic_scl_recovery) {
 295                 /* Generic SCL recovery */
 296                 if (!bri->set_scl || !bri->get_scl) {
 297                         err_str = "no {get|set}_scl() found";
 298                         goto err;
 299                 }
 300         }
 301
 302         return;
 303  err:
 304         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 305         adap->bus_recovery_info = NULL;
 306 }
 307
 308 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 309 {
 310         struct i2c_adapter *adap = client->adapter;
 311         unsigned int irq;
 312
 313         if (!adap->host_notify_domain)
 314                 return -ENXIO;
 315
 316         if (client->flags & I2C_CLIENT_TEN)
 317                 return -EINVAL;
 318
 319         irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 320         if (!irq)
 321                 irq = irq_create_mapping(adap->host_notify_domain,
 322                                          client->addr);
 323
 324         return irq > 0 ? irq : -ENXIO;
 325 }
 326
 327 static int i2c_device_probe(struct device *dev)
 328 {
 329         struct i2c_client       *client = i2c_verify_client(dev);
 330         struct i2c_driver       *driver;
 331         int status;
 332
 333         if (!client)
 334                 return 0;
 335
 336         driver = to_i2c_driver(dev->driver);
 337
 338         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 339                 int irq = -ENOENT;
 340
 341                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 342                         dev_dbg(dev, "Using Host Notify IRQ\n");
 343                         irq = i2c_smbus_host_notify_to_irq(client);
 344                 } else if (dev->of_node) {
 345                         irq = of_irq_get_byname(dev->of_node, "irq");
 346                         if (irq == -EINVAL || irq == -ENODATA)
 347                                 irq = of_irq_get(dev->of_node, 0);
 348                 } else if (ACPI_COMPANION(dev)) {
 349                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 350                 }
 351                 if (irq == -EPROBE_DEFER)
 352                         return irq;
 353
 354                 if (irq < 0)
 355                         irq = 0;
 356
 357                 client->irq = irq;
 358         }
 359
 360         /*
 361          * An I2C ID table is not mandatory, if and only if, a suitable OF
 362          * or ACPI ID table is supplied for the probing device.
 363          */
 364         if (!driver->id_table &&
 365             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 366             !i2c_of_match_device(dev->driver->of_match_table, client))
 367                 return -ENODEV;
 368
 369         if (client->flags & I2C_CLIENT_WAKE) {
 370                 int wakeirq = -ENOENT;
 371
 372                 if (dev->of_node) {
 373                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 374                         if (wakeirq == -EPROBE_DEFER)
 375                                 return wakeirq;
 376                 }
 377
 378                 device_init_wakeup(&client->dev, true);
 379
 380                 if (wakeirq > 0 && wakeirq != client->irq)
 381                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 382                 else if (client->irq > 0)
 383                         status = dev_pm_set_wake_irq(dev, client->irq);
 384                 else
 385                         status = 0;
 386
 387                 if (status)
 388                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 389         }
 390
 391         dev_dbg(dev, "probe\n");
 392
 393         status = of_clk_set_defaults(dev->of_node, false);
 394         if (status < 0)
 395                 goto err_clear_wakeup_irq;
 396
 397         status = dev_pm_domain_attach(&client->dev, true);
 398         if (status == -EPROBE_DEFER)
 399                 goto err_clear_wakeup_irq;
 400
 401         /*
 402          * When there are no more users of probe(),
 403          * rename probe_new to probe.
 404          */
 405         if (driver->probe_new)
 406                 status = driver->probe_new(client);
 407         else if (driver->probe)
 408                 status = driver->probe(client,
 409                                        i2c_match_id(driver->id_table, client));
 410         else
 411                 status = -EINVAL;
 412
 413         if (status)
 414                 goto err_detach_pm_domain;
 415
 416         return 0;
 417
 418 err_detach_pm_domain:
 419         dev_pm_domain_detach(&client->dev, true);
 420 err_clear_wakeup_irq:
 421         dev_pm_clear_wake_irq(&client->dev);
 422         device_init_wakeup(&client->dev, false);
 423         return status;
 424 }
 425
 426 static int i2c_device_remove(struct device *dev)
 427 {
 428         struct i2c_client       *client = i2c_verify_client(dev);
 429         struct i2c_driver       *driver;
 430         int status = 0;
 431
 432         if (!client || !dev->driver)
 433                 return 0;
 434
 435         driver = to_i2c_driver(dev->driver);
 436         if (driver->remove) {
 437                 dev_dbg(dev, "remove\n");
 438                 status = driver->remove(client);
 439         }
 440
 441         dev_pm_domain_detach(&client->dev, true);
 442
 443         dev_pm_clear_wake_irq(&client->dev);
 444         device_init_wakeup(&client->dev, false);
 445
 446         return status;
 447 }
 448
 449 static void i2c_device_shutdown(struct device *dev)
 450 {
 451         struct i2c_client *client = i2c_verify_client(dev);
 452         struct i2c_driver *driver;
 453
 454         if (!client || !dev->driver)
 455                 return;
 456         driver = to_i2c_driver(dev->driver);
 457         if (driver->shutdown)
 458                 driver->shutdown(client);
 459 }
 460
 461 static void i2c_client_dev_release(struct device *dev)
 462 {
 463         kfree(to_i2c_client(dev));
 464 }
 465
 466 static ssize_t
 467 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 468 {
 469         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 470                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 471 }
 472 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 473
 474 static ssize_t
 475 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 476 {
 477         struct i2c_client *client = to_i2c_client(dev);
 478         int len;
 479
 480         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 481         if (len != -ENODEV)
 482                 return len;
 483
 484         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 485 }
 486 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 487
 488 static struct attribute *i2c_dev_attrs[] = {
 489         &dev_attr_name.attr,
 490         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 491         &dev_attr_modalias.attr,
 492         NULL
 493 };
 494 ATTRIBUTE_GROUPS(i2c_dev);
 495
 496 struct bus_type i2c_bus_type = {
 497         .name           = "i2c",
 498         .match          = i2c_device_match,
 499         .probe          = i2c_device_probe,
 500         .remove         = i2c_device_remove,
 501         .shutdown       = i2c_device_shutdown,
 502 };
 503 EXPORT_SYMBOL_GPL(i2c_bus_type);
 504
 505 struct device_type i2c_client_type = {
 506         .groups         = i2c_dev_groups,
 507         .uevent         = i2c_device_uevent,
 508         .release        = i2c_client_dev_release,
 509 };
 510 EXPORT_SYMBOL_GPL(i2c_client_type);
 511
 512
 513 /**
 514  * i2c_verify_client - return parameter as i2c_client, or NULL
 515  * @dev: device, probably from some driver model iterator
 516  *
 517  * When traversing the driver model tree, perhaps using driver model
 518  * iterators like @device_for_each_child(), you can't assume very much
 519  * about the nodes you find.  Use this function to avoid oopses caused
 520  * by wrongly treating some non-I2C device as an i2c_client.
 521  */
 522 struct i2c_client *i2c_verify_client(struct device *dev)
 523 {
 524         return (dev->type == &i2c_client_type)
 525                         ? to_i2c_client(dev)
 526                         : NULL;
 527 }
 528 EXPORT_SYMBOL(i2c_verify_client);
 529
 530
 531 /* Return a unique address which takes the flags of the client into account */
 532 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 533 {
 534         unsigned short addr = client->addr;
 535
 536         /* For some client flags, add an arbitrary offset to avoid collisions */
 537         if (client->flags & I2C_CLIENT_TEN)
 538                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 539
 540         if (client->flags & I2C_CLIENT_SLAVE)
 541                 addr |= I2C_ADDR_OFFSET_SLAVE;
 542
 543         return addr;
 544 }
 545
 546 /* This is a permissive address validity check, I2C address map constraints
 547  * are purposely not enforced, except for the general call address. */
 548 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
 549 {
 550         if (flags & I2C_CLIENT_TEN) {
 551                 /* 10-bit address, all values are valid */
 552                 if (addr > 0x3ff)
 553                         return -EINVAL;
 554         } else {
 555                 /* 7-bit address, reject the general call address */
 556                 if (addr == 0x00 || addr > 0x7f)
 557                         return -EINVAL;
 558         }
 559         return 0;
 560 }
 561
 562 /* And this is a strict address validity check, used when probing. If a
 563  * device uses a reserved address, then it shouldn't be probed. 7-bit
 564  * addressing is assumed, 10-bit address devices are rare and should be
 565  * explicitly enumerated. */
 566 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 567 {
 568         /*
 569          * Reserved addresses per I2C specification:
 570          *  0x00       General call address / START byte
 571          *  0x01       CBUS address
 572          *  0x02       Reserved for different bus format
 573          *  0x03       Reserved for future purposes
 574          *  0x04-0x07  Hs-mode master code
 575          *  0x78-0x7b  10-bit slave addressing
 576          *  0x7c-0x7f  Reserved for future purposes
 577          */
 578         if (addr < 0x08 || addr > 0x77)
 579                 return -EINVAL;
 580         return 0;
 581 }
 582
 583 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 584 {
 585         struct i2c_client       *client = i2c_verify_client(dev);
 586         int                     addr = *(int *)addrp;
 587
 588         if (client && i2c_encode_flags_to_addr(client) == addr)
 589                 return -EBUSY;
 590         return 0;
 591 }
 592
 593 /* walk up mux tree */
 594 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 595 {
 596         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 597         int result;
 598
 599         result = device_for_each_child(&adapter->dev, &addr,
 600                                         __i2c_check_addr_busy);
 601
 602         if (!result && parent)
 603                 result = i2c_check_mux_parents(parent, addr);
 604
 605         return result;
 606 }
 607
 608 /* recurse down mux tree */
 609 static int i2c_check_mux_children(struct device *dev, void *addrp)
 610 {
 611         int result;
 612
 613         if (dev->type == &i2c_adapter_type)
 614                 result = device_for_each_child(dev, addrp,
 615                                                 i2c_check_mux_children);
 616         else
 617                 result = __i2c_check_addr_busy(dev, addrp);
 618
 619         return result;
 620 }
 621
 622 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 623 {
 624         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 625         int result = 0;
 626
 627         if (parent)
 628                 result = i2c_check_mux_parents(parent, addr);
 629
 630         if (!result)
 631                 result = device_for_each_child(&adapter->dev, &addr,
 632                                                 i2c_check_mux_children);
 633
 634         return result;
 635 }
 636
 637 /**
 638  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 639  * @adapter: Target I2C bus segment
 640  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 641  *      locks only this branch in the adapter tree
 642  */
 643 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 644                                  unsigned int flags)
 645 {
 646         rt_mutex_lock(&adapter->bus_lock);
 647 }
 648
 649 /**
 650  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 651  * @adapter: Target I2C bus segment
 652  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 653  *      trylocks only this branch in the adapter tree
 654  */
 655 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 656                                    unsigned int flags)
 657 {
 658         return rt_mutex_trylock(&adapter->bus_lock);
 659 }
 660
 661 /**
 662  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 663  * @adapter: Target I2C bus segment
 664  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 665  *      unlocks only this branch in the adapter tree
 666  */
 667 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 668                                    unsigned int flags)
 669 {
 670         rt_mutex_unlock(&adapter->bus_lock);
 671 }
 672
 673 static void i2c_dev_set_name(struct i2c_adapter *adap,
 674                              struct i2c_client *client,
 675                              struct i2c_board_info const *info)
 676 {
 677         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 678
 679         if (info && info->dev_name) {
 680                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 681                 return;
 682         }
 683
 684         if (adev) {
 685                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 686                 return;
 687         }
 688
 689         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 690                      i2c_encode_flags_to_addr(client));
 691 }
 692
 693 static int i2c_dev_irq_from_resources(const struct resource *resources,
 694                                       unsigned int num_resources)
 695 {
 696         struct irq_data *irqd;
 697         int i;
 698
 699         for (i = 0; i < num_resources; i++) {
 700                 const struct resource *r = &resources[i];
 701
 702                 if (resource_type(r) != IORESOURCE_IRQ)
 703                         continue;
 704
 705                 if (r->flags & IORESOURCE_BITS) {
 706                         irqd = irq_get_irq_data(r->start);
 707                         if (!irqd)
 708                                 break;
 709
 710                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 711                 }
 712
 713                 return r->start;
 714         }
 715
 716         return 0;
 717 }
 718
 719 /**
 720  * i2c_new_device - instantiate an i2c device
 721  * @adap: the adapter managing the device
 722  * @info: describes one I2C device; bus_num is ignored
 723  * Context: can sleep
 724  *
 725  * Create an i2c device. Binding is handled through driver model
 726  * probe()/remove() methods.  A driver may be bound to this device when we
 727  * return from this function, or any later moment (e.g. maybe hotplugging will
 728  * load the driver module).  This call is not appropriate for use by mainboard
 729  * initialization logic, which usually runs during an arch_initcall() long
 730  * before any i2c_adapter could exist.
 731  *
 732  * This returns the new i2c client, which may be saved for later use with
 733  * i2c_unregister_device(); or NULL to indicate an error.
 734  */
 735 struct i2c_client *
 736 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 737 {
 738         struct i2c_client       *client;
 739         int                     status;
 740
 741         client = kzalloc(sizeof *client, GFP_KERNEL);
 742         if (!client)
 743                 return NULL;
 744
 745         client->adapter = adap;
 746
 747         client->dev.platform_data = info->platform_data;
 748
 749         if (info->archdata)
 750                 client->dev.archdata = *info->archdata;
 751
 752         client->flags = info->flags;
 753         client->addr = info->addr;
 754
 755         client->irq = info->irq;
 756         if (!client->irq)
 757                 client->irq = i2c_dev_irq_from_resources(info->resources,
 758                                                          info->num_resources);
 759
 760         strlcpy(client->name, info->type, sizeof(client->name));
 761
 762         status = i2c_check_addr_validity(client->addr, client->flags);
 763         if (status) {
 764                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 765                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 766                 goto out_err_silent;
 767         }
 768
 769         /* Check for address business */
 770         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 771         if (status)
 772                 goto out_err;
 773
 774         client->dev.parent = &client->adapter->dev;
 775         client->dev.bus = &i2c_bus_type;
 776         client->dev.type = &i2c_client_type;
 777         client->dev.of_node = info->of_node;
 778         client->dev.fwnode = info->fwnode;
 779
 780         i2c_dev_set_name(adap, client, info);
 781
 782         if (info->properties) {
 783                 status = device_add_properties(&client->dev, info->properties);
 784                 if (status) {
 785                         dev_err(&adap->dev,
 786                                 "Failed to add properties to client %s: %d\n",
 787                                 client->name, status);
 788                         goto out_err;
 789                 }
 790         }
 791
 792         status = device_register(&client->dev);
 793         if (status)
 794                 goto out_free_props;
 795
 796         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 797                 client->name, dev_name(&client->dev));
 798
 799         return client;
 800
 801 out_free_props:
 802         if (info->properties)
 803                 device_remove_properties(&client->dev);
 804 out_err:
 805         dev_err(&adap->dev,
 806                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 807                 client->name, client->addr, status);
 808 out_err_silent:
 809         kfree(client);
 810         return NULL;
 811 }
 812 EXPORT_SYMBOL_GPL(i2c_new_device);
 813
 814
 815 /**
 816  * i2c_unregister_device - reverse effect of i2c_new_device()
 817  * @client: value returned from i2c_new_device()
 818  * Context: can sleep
 819  */
 820 void i2c_unregister_device(struct i2c_client *client)
 821 {
 822         if (!client)
 823                 return;
 824         if (client->dev.of_node)
 825                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 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         /* Let legacy drivers scan this bus for matching devices */
1132         if (driver->attach_adapter) {
1133                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1134                          driver->driver.name);
1135                 dev_warn(&adap->dev,
1136                          "Please use another way to instantiate your i2c_client\n");
1137                 /* We ignore the return code; if it fails, too bad */
1138                 driver->attach_adapter(adap);
1139         }
1140         return 0;
1141 }
1142
1143 static int __process_new_adapter(struct device_driver *d, void *data)
1144 {
1145         return i2c_do_add_adapter(to_i2c_driver(d), data);
1146 }
1147
1148 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1149         .lock_bus =    i2c_adapter_lock_bus,
1150         .trylock_bus = i2c_adapter_trylock_bus,
1151         .unlock_bus =  i2c_adapter_unlock_bus,
1152 };
1153
1154 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1155 {
1156         struct irq_domain *domain = adap->host_notify_domain;
1157         irq_hw_number_t hwirq;
1158
1159         if (!domain)
1160                 return;
1161
1162         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1163                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1164
1165         irq_domain_remove(domain);
1166         adap->host_notify_domain = NULL;
1167 }
1168
1169 static int i2c_host_notify_irq_map(struct irq_domain *h,
1170                                           unsigned int virq,
1171                                           irq_hw_number_t hw_irq_num)
1172 {
1173         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1174
1175         return 0;
1176 }
1177
1178 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1179         .map = i2c_host_notify_irq_map,
1180 };
1181
1182 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1183 {
1184         struct irq_domain *domain;
1185
1186         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1187                 return 0;
1188
1189         domain = irq_domain_create_linear(adap->dev.fwnode,
1190                                           I2C_ADDR_7BITS_COUNT,
1191                                           &i2c_host_notify_irq_ops, adap);
1192         if (!domain)
1193                 return -ENOMEM;
1194
1195         adap->host_notify_domain = domain;
1196
1197         return 0;
1198 }
1199
1200 /**
1201  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1202  * I2C client.
1203  * @adap: the adapter
1204  * @addr: the I2C address of the notifying device
1205  * Context: can't sleep
1206  *
1207  * Helper function to be called from an I2C bus driver's interrupt
1208  * handler. It will schedule the Host Notify IRQ.
1209  */
1210 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1211 {
1212         int irq;
1213
1214         if (!adap)
1215                 return -EINVAL;
1216
1217         irq = irq_find_mapping(adap->host_notify_domain, addr);
1218         if (irq <= 0)
1219                 return -ENXIO;
1220
1221         generic_handle_irq(irq);
1222
1223         return 0;
1224 }
1225 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1226
1227 static int i2c_register_adapter(struct i2c_adapter *adap)
1228 {
1229         int res = -EINVAL;
1230
1231         /* Can't register until after driver model init */
1232         if (WARN_ON(!is_registered)) {
1233                 res = -EAGAIN;
1234                 goto out_list;
1235         }
1236
1237         /* Sanity checks */
1238         if (WARN(!adap->name[0], "i2c adapter has no name"))
1239                 goto out_list;
1240
1241         if (!adap->algo) {
1242                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1243                 goto out_list;
1244         }
1245
1246         if (!adap->lock_ops)
1247                 adap->lock_ops = &i2c_adapter_lock_ops;
1248
1249         rt_mutex_init(&adap->bus_lock);
1250         rt_mutex_init(&adap->mux_lock);
1251         mutex_init(&adap->userspace_clients_lock);
1252         INIT_LIST_HEAD(&adap->userspace_clients);
1253
1254         /* Set default timeout to 1 second if not already set */
1255         if (adap->timeout == 0)
1256                 adap->timeout = HZ;
1257
1258         /* register soft irqs for Host Notify */
1259         res = i2c_setup_host_notify_irq_domain(adap);
1260         if (res) {
1261                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1262                        adap->name, res);
1263                 goto out_list;
1264         }
1265
1266         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1267         adap->dev.bus = &i2c_bus_type;
1268         adap->dev.type = &i2c_adapter_type;
1269         res = device_register(&adap->dev);
1270         if (res) {
1271                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1272                 goto out_list;
1273         }
1274
1275         res = of_i2c_setup_smbus_alert(adap);
1276         if (res)
1277                 goto out_reg;
1278
1279         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1280
1281         pm_runtime_no_callbacks(&adap->dev);
1282         pm_suspend_ignore_children(&adap->dev, true);
1283         pm_runtime_enable(&adap->dev);
1284
1285 #ifdef CONFIG_I2C_COMPAT
1286         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1287                                        adap->dev.parent);
1288         if (res)
1289                 dev_warn(&adap->dev,
1290                          "Failed to create compatibility class link\n");
1291 #endif
1292
1293         i2c_init_recovery(adap);
1294
1295         /* create pre-declared device nodes */
1296         of_i2c_register_devices(adap);
1297         i2c_acpi_register_devices(adap);
1298         i2c_acpi_install_space_handler(adap);
1299
1300         if (adap->nr < __i2c_first_dynamic_bus_num)
1301                 i2c_scan_static_board_info(adap);
1302
1303         /* Notify drivers */
1304         mutex_lock(&core_lock);
1305         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1306         mutex_unlock(&core_lock);
1307
1308         return 0;
1309
1310 out_reg:
1311         init_completion(&adap->dev_released);
1312         device_unregister(&adap->dev);
1313         wait_for_completion(&adap->dev_released);
1314 out_list:
1315         mutex_lock(&core_lock);
1316         idr_remove(&i2c_adapter_idr, adap->nr);
1317         mutex_unlock(&core_lock);
1318         return res;
1319 }
1320
1321 /**
1322  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1323  * @adap: the adapter to register (with adap->nr initialized)
1324  * Context: can sleep
1325  *
1326  * See i2c_add_numbered_adapter() for details.
1327  */
1328 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1329 {
1330         int id;
1331
1332         mutex_lock(&core_lock);
1333         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1334         mutex_unlock(&core_lock);
1335         if (WARN(id < 0, "couldn't get idr"))
1336                 return id == -ENOSPC ? -EBUSY : id;
1337
1338         return i2c_register_adapter(adap);
1339 }
1340
1341 /**
1342  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1343  * @adapter: the adapter to add
1344  * Context: can sleep
1345  *
1346  * This routine is used to declare an I2C adapter when its bus number
1347  * doesn't matter or when its bus number is specified by an dt alias.
1348  * Examples of bases when the bus number doesn't matter: I2C adapters
1349  * dynamically added by USB links or PCI plugin cards.
1350  *
1351  * When this returns zero, a new bus number was allocated and stored
1352  * in adap->nr, and the specified adapter became available for clients.
1353  * Otherwise, a negative errno value is returned.
1354  */
1355 int i2c_add_adapter(struct i2c_adapter *adapter)
1356 {
1357         struct device *dev = &adapter->dev;
1358         int id;
1359
1360         if (dev->of_node) {
1361                 id = of_alias_get_id(dev->of_node, "i2c");
1362                 if (id >= 0) {
1363                         adapter->nr = id;
1364                         return __i2c_add_numbered_adapter(adapter);
1365                 }
1366         }
1367
1368         mutex_lock(&core_lock);
1369         id = idr_alloc(&i2c_adapter_idr, adapter,
1370                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1371         mutex_unlock(&core_lock);
1372         if (WARN(id < 0, "couldn't get idr"))
1373                 return id;
1374
1375         adapter->nr = id;
1376
1377         return i2c_register_adapter(adapter);
1378 }
1379 EXPORT_SYMBOL(i2c_add_adapter);
1380
1381 /**
1382  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1383  * @adap: the adapter to register (with adap->nr initialized)
1384  * Context: can sleep
1385  *
1386  * This routine is used to declare an I2C adapter when its bus number
1387  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1388  * or otherwise built in to the system's mainboard, and where i2c_board_info
1389  * is used to properly configure I2C devices.
1390  *
1391  * If the requested bus number is set to -1, then this function will behave
1392  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1393  *
1394  * If no devices have pre-been declared for this bus, then be sure to
1395  * register the adapter before any dynamically allocated ones.  Otherwise
1396  * the required bus ID may not be available.
1397  *
1398  * When this returns zero, the specified adapter became available for
1399  * clients using the bus number provided in adap->nr.  Also, the table
1400  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1401  * and the appropriate driver model device nodes are created.  Otherwise, a
1402  * negative errno value is returned.
1403  */
1404 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1405 {
1406         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1407                 return i2c_add_adapter(adap);
1408
1409         return __i2c_add_numbered_adapter(adap);
1410 }
1411 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1412
1413 static void i2c_do_del_adapter(struct i2c_driver *driver,
1414                               struct i2c_adapter *adapter)
1415 {
1416         struct i2c_client *client, *_n;
1417
1418         /* Remove the devices we created ourselves as the result of hardware
1419          * probing (using a driver's detect method) */
1420         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1421                 if (client->adapter == adapter) {
1422                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1423                                 client->name, client->addr);
1424                         list_del(&client->detected);
1425                         i2c_unregister_device(client);
1426                 }
1427         }
1428 }
1429
1430 static int __unregister_client(struct device *dev, void *dummy)
1431 {
1432         struct i2c_client *client = i2c_verify_client(dev);
1433         if (client && strcmp(client->name, "dummy"))
1434                 i2c_unregister_device(client);
1435         return 0;
1436 }
1437
1438 static int __unregister_dummy(struct device *dev, void *dummy)
1439 {
1440         struct i2c_client *client = i2c_verify_client(dev);
1441         i2c_unregister_device(client);
1442         return 0;
1443 }
1444
1445 static int __process_removed_adapter(struct device_driver *d, void *data)
1446 {
1447         i2c_do_del_adapter(to_i2c_driver(d), data);
1448         return 0;
1449 }
1450
1451 /**
1452  * i2c_del_adapter - unregister I2C adapter
1453  * @adap: the adapter being unregistered
1454  * Context: can sleep
1455  *
1456  * This unregisters an I2C adapter which was previously registered
1457  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1458  */
1459 void i2c_del_adapter(struct i2c_adapter *adap)
1460 {
1461         struct i2c_adapter *found;
1462         struct i2c_client *client, *next;
1463
1464         /* First make sure that this adapter was ever added */
1465         mutex_lock(&core_lock);
1466         found = idr_find(&i2c_adapter_idr, adap->nr);
1467         mutex_unlock(&core_lock);
1468         if (found != adap) {
1469                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1470                 return;
1471         }
1472
1473         i2c_acpi_remove_space_handler(adap);
1474         /* Tell drivers about this removal */
1475         mutex_lock(&core_lock);
1476         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1477                                __process_removed_adapter);
1478         mutex_unlock(&core_lock);
1479
1480         /* Remove devices instantiated from sysfs */
1481         mutex_lock_nested(&adap->userspace_clients_lock,
1482                           i2c_adapter_depth(adap));
1483         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1484                                  detected) {
1485                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1486                         client->addr);
1487                 list_del(&client->detected);
1488                 i2c_unregister_device(client);
1489         }
1490         mutex_unlock(&adap->userspace_clients_lock);
1491
1492         /* Detach any active clients. This can't fail, thus we do not
1493          * check the returned value. This is a two-pass process, because
1494          * we can't remove the dummy devices during the first pass: they
1495          * could have been instantiated by real devices wishing to clean
1496          * them up properly, so we give them a chance to do that first. */
1497         device_for_each_child(&adap->dev, NULL, __unregister_client);
1498         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1499
1500 #ifdef CONFIG_I2C_COMPAT
1501         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1502                                  adap->dev.parent);
1503 #endif
1504
1505         /* device name is gone after device_unregister */
1506         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1507
1508         pm_runtime_disable(&adap->dev);
1509
1510         i2c_host_notify_irq_teardown(adap);
1511
1512         /* wait until all references to the device are gone
1513          *
1514          * FIXME: This is old code and should ideally be replaced by an
1515          * alternative which results in decoupling the lifetime of the struct
1516          * device from the i2c_adapter, like spi or netdev do. Any solution
1517          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1518          */
1519         init_completion(&adap->dev_released);
1520         device_unregister(&adap->dev);
1521         wait_for_completion(&adap->dev_released);
1522
1523         /* free bus id */
1524         mutex_lock(&core_lock);
1525         idr_remove(&i2c_adapter_idr, adap->nr);
1526         mutex_unlock(&core_lock);
1527
1528         /* Clear the device structure in case this adapter is ever going to be
1529            added again */
1530         memset(&adap->dev, 0, sizeof(adap->dev));
1531 }
1532 EXPORT_SYMBOL(i2c_del_adapter);
1533
1534 /**
1535  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1536  * @dev: The device to scan for I2C timing properties
1537  * @t: the i2c_timings struct to be filled with values
1538  * @use_defaults: bool to use sane defaults derived from the I2C specification
1539  *                when properties are not found, otherwise use 0
1540  *
1541  * Scan the device for the generic I2C properties describing timing parameters
1542  * for the signal and fill the given struct with the results. If a property was
1543  * not found and use_defaults was true, then maximum timings are assumed which
1544  * are derived from the I2C specification. If use_defaults is not used, the
1545  * results will be 0, so drivers can apply their own defaults later. The latter
1546  * is mainly intended for avoiding regressions of existing drivers which want
1547  * to switch to this function. New drivers almost always should use the defaults.
1548  */
1549
1550 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1551 {
1552         int ret;
1553
1554         memset(t, 0, sizeof(*t));
1555
1556         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1557         if (ret && use_defaults)
1558                 t->bus_freq_hz = 100000;
1559
1560         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1561         if (ret && use_defaults) {
1562                 if (t->bus_freq_hz <= 100000)
1563                         t->scl_rise_ns = 1000;
1564                 else if (t->bus_freq_hz <= 400000)
1565                         t->scl_rise_ns = 300;
1566                 else
1567                         t->scl_rise_ns = 120;
1568         }
1569
1570         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1571         if (ret && use_defaults) {
1572                 if (t->bus_freq_hz <= 400000)
1573                         t->scl_fall_ns = 300;
1574                 else
1575                         t->scl_fall_ns = 120;
1576         }
1577
1578         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1579
1580         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1581         if (ret && use_defaults)
1582                 t->sda_fall_ns = t->scl_fall_ns;
1583 }
1584 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1585
1586 /* ------------------------------------------------------------------------- */
1587
1588 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1589 {
1590         int res;
1591
1592         mutex_lock(&core_lock);
1593         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1594         mutex_unlock(&core_lock);
1595
1596         return res;
1597 }
1598 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1599
1600 static int __process_new_driver(struct device *dev, void *data)
1601 {
1602         if (dev->type != &i2c_adapter_type)
1603                 return 0;
1604         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1605 }
1606
1607 /*
1608  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1609  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1610  */
1611
1612 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1613 {
1614         int res;
1615
1616         /* Can't register until after driver model init */
1617         if (WARN_ON(!is_registered))
1618                 return -EAGAIN;
1619
1620         /* add the driver to the list of i2c drivers in the driver core */
1621         driver->driver.owner = owner;
1622         driver->driver.bus = &i2c_bus_type;
1623         INIT_LIST_HEAD(&driver->clients);
1624
1625         /* When registration returns, the driver core
1626          * will have called probe() for all matching-but-unbound devices.
1627          */
1628         res = driver_register(&driver->driver);
1629         if (res)
1630                 return res;
1631
1632         pr_debug("driver [%s] registered\n", driver->driver.name);
1633
1634         /* Walk the adapters that are already present */
1635         i2c_for_each_dev(driver, __process_new_driver);
1636
1637         return 0;
1638 }
1639 EXPORT_SYMBOL(i2c_register_driver);
1640
1641 static int __process_removed_driver(struct device *dev, void *data)
1642 {
1643         if (dev->type == &i2c_adapter_type)
1644                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1645         return 0;
1646 }
1647
1648 /**
1649  * i2c_del_driver - unregister I2C driver
1650  * @driver: the driver being unregistered
1651  * Context: can sleep
1652  */
1653 void i2c_del_driver(struct i2c_driver *driver)
1654 {
1655         i2c_for_each_dev(driver, __process_removed_driver);
1656
1657         driver_unregister(&driver->driver);
1658         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1659 }
1660 EXPORT_SYMBOL(i2c_del_driver);
1661
1662 /* ------------------------------------------------------------------------- */
1663
1664 /**
1665  * i2c_use_client - increments the reference count of the i2c client structure
1666  * @client: the client being referenced
1667  *
1668  * Each live reference to a client should be refcounted. The driver model does
1669  * that automatically as part of driver binding, so that most drivers don't
1670  * need to do this explicitly: they hold a reference until they're unbound
1671  * from the device.
1672  *
1673  * A pointer to the client with the incremented reference counter is returned.
1674  */
1675 struct i2c_client *i2c_use_client(struct i2c_client *client)
1676 {
1677         if (client && get_device(&client->dev))
1678                 return client;
1679         return NULL;
1680 }
1681 EXPORT_SYMBOL(i2c_use_client);
1682
1683 /**
1684  * i2c_release_client - release a use of the i2c client structure
1685  * @client: the client being no longer referenced
1686  *
1687  * Must be called when a user of a client is finished with it.
1688  */
1689 void i2c_release_client(struct i2c_client *client)
1690 {
1691         if (client)
1692                 put_device(&client->dev);
1693 }
1694 EXPORT_SYMBOL(i2c_release_client);
1695
1696 struct i2c_cmd_arg {
1697         unsigned        cmd;
1698         void            *arg;
1699 };
1700
1701 static int i2c_cmd(struct device *dev, void *_arg)
1702 {
1703         struct i2c_client       *client = i2c_verify_client(dev);
1704         struct i2c_cmd_arg      *arg = _arg;
1705         struct i2c_driver       *driver;
1706
1707         if (!client || !client->dev.driver)
1708                 return 0;
1709
1710         driver = to_i2c_driver(client->dev.driver);
1711         if (driver->command)
1712                 driver->command(client, arg->cmd, arg->arg);
1713         return 0;
1714 }
1715
1716 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1717 {
1718         struct i2c_cmd_arg      cmd_arg;
1719
1720         cmd_arg.cmd = cmd;
1721         cmd_arg.arg = arg;
1722         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1723 }
1724 EXPORT_SYMBOL(i2c_clients_command);
1725
1726 static int __init i2c_init(void)
1727 {
1728         int retval;
1729
1730         retval = of_alias_get_highest_id("i2c");
1731
1732         down_write(&__i2c_board_lock);
1733         if (retval >= __i2c_first_dynamic_bus_num)
1734                 __i2c_first_dynamic_bus_num = retval + 1;
1735         up_write(&__i2c_board_lock);
1736
1737         retval = bus_register(&i2c_bus_type);
1738         if (retval)
1739                 return retval;
1740
1741         is_registered = true;
1742
1743 #ifdef CONFIG_I2C_COMPAT
1744         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1745         if (!i2c_adapter_compat_class) {
1746                 retval = -ENOMEM;
1747                 goto bus_err;
1748         }
1749 #endif
1750         retval = i2c_add_driver(&dummy_driver);
1751         if (retval)
1752                 goto class_err;
1753
1754         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1755                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1756         if (IS_ENABLED(CONFIG_ACPI))
1757                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1758
1759         return 0;
1760
1761 class_err:
1762 #ifdef CONFIG_I2C_COMPAT
1763         class_compat_unregister(i2c_adapter_compat_class);
1764 bus_err:
1765 #endif
1766         is_registered = false;
1767         bus_unregister(&i2c_bus_type);
1768         return retval;
1769 }
1770
1771 static void __exit i2c_exit(void)
1772 {
1773         if (IS_ENABLED(CONFIG_ACPI))
1774                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1775         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1776                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1777         i2c_del_driver(&dummy_driver);
1778 #ifdef CONFIG_I2C_COMPAT
1779         class_compat_unregister(i2c_adapter_compat_class);
1780 #endif
1781         bus_unregister(&i2c_bus_type);
1782         tracepoint_synchronize_unregister();
1783 }
1784
1785 /* We must initialize early, because some subsystems register i2c drivers
1786  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1787  */
1788 postcore_initcall(i2c_init);
1789 module_exit(i2c_exit);
1790
1791 /* ----------------------------------------------------
1792  * the functional interface to the i2c busses.
1793  * ----------------------------------------------------
1794  */
1795
1796 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1797 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1798
1799 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1800 {
1801         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1802                             err_msg, msg->addr, msg->len,
1803                             msg->flags & I2C_M_RD ? "read" : "write");
1804         return -EOPNOTSUPP;
1805 }
1806
1807 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1808 {
1809         const struct i2c_adapter_quirks *q = adap->quirks;
1810         int max_num = q->max_num_msgs, i;
1811         bool do_len_check = true;
1812
1813         if (q->flags & I2C_AQ_COMB) {
1814                 max_num = 2;
1815
1816                 /* special checks for combined messages */
1817                 if (num == 2) {
1818                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1819                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1820
1821                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1822                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1823
1824                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1825                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1826
1827                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1828                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1829
1830                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1831                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1832
1833                         do_len_check = false;
1834                 }
1835         }
1836
1837         if (i2c_quirk_exceeded(num, max_num))
1838                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1839
1840         for (i = 0; i < num; i++) {
1841                 u16 len = msgs[i].len;
1842
1843                 if (msgs[i].flags & I2C_M_RD) {
1844                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1845                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1846                 } else {
1847                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1848                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
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 (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1873                 return -EOPNOTSUPP;
1874
1875         /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1876          * enabled.  This is an efficient way of keeping the for-loop from
1877          * being executed when not needed.
1878          */
1879         if (static_key_false(&i2c_trace_msg)) {
1880                 int i;
1881                 for (i = 0; i < num; i++)
1882                         if (msgs[i].flags & I2C_M_RD)
1883                                 trace_i2c_read(adap, &msgs[i], i);
1884                         else
1885                                 trace_i2c_write(adap, &msgs[i], i);
1886         }
1887
1888         /* Retry automatically on arbitration loss */
1889         orig_jiffies = jiffies;
1890         for (ret = 0, try = 0; try <= adap->retries; try++) {
1891                 ret = adap->algo->master_xfer(adap, msgs, num);
1892                 if (ret != -EAGAIN)
1893                         break;
1894                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1895                         break;
1896         }
1897
1898         if (static_key_false(&i2c_trace_msg)) {
1899                 int i;
1900                 for (i = 0; i < ret; i++)
1901                         if (msgs[i].flags & I2C_M_RD)
1902                                 trace_i2c_reply(adap, &msgs[i], i);
1903                 trace_i2c_result(adap, i, ret);
1904         }
1905
1906         return ret;
1907 }
1908 EXPORT_SYMBOL(__i2c_transfer);
1909
1910 /**
1911  * i2c_transfer - execute a single or combined I2C message
1912  * @adap: Handle to I2C bus
1913  * @msgs: One or more messages to execute before STOP is issued to
1914  *      terminate the operation; each message begins with a START.
1915  * @num: Number of messages to be executed.
1916  *
1917  * Returns negative errno, else the number of messages executed.
1918  *
1919  * Note that there is no requirement that each message be sent to
1920  * the same slave address, although that is the most common model.
1921  */
1922 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1923 {
1924         int ret;
1925
1926         /* REVISIT the fault reporting model here is weak:
1927          *
1928          *  - When we get an error after receiving N bytes from a slave,
1929          *    there is no way to report "N".
1930          *
1931          *  - When we get a NAK after transmitting N bytes to a slave,
1932          *    there is no way to report "N" ... or to let the master
1933          *    continue executing the rest of this combined message, if
1934          *    that's the appropriate response.
1935          *
1936          *  - When for example "num" is two and we successfully complete
1937          *    the first message but get an error part way through the
1938          *    second, it's unclear whether that should be reported as
1939          *    one (discarding status on the second message) or errno
1940          *    (discarding status on the first one).
1941          */
1942
1943         if (adap->algo->master_xfer) {
1944 #ifdef DEBUG
1945                 for (ret = 0; ret < num; ret++) {
1946                         dev_dbg(&adap->dev,
1947                                 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1948                                 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1949                                 msgs[ret].addr, msgs[ret].len,
1950                                 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1951                 }
1952 #endif
1953
1954                 if (in_atomic() || irqs_disabled()) {
1955                         ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1956                         if (!ret)
1957                                 /* I2C activity is ongoing. */
1958                                 return -EAGAIN;
1959                 } else {
1960                         i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1961                 }
1962
1963                 ret = __i2c_transfer(adap, msgs, num);
1964                 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1965
1966                 return ret;
1967         } else {
1968                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1969                 return -EOPNOTSUPP;
1970         }
1971 }
1972 EXPORT_SYMBOL(i2c_transfer);
1973
1974 /**
1975  * i2c_master_send - issue a single I2C message in master transmit mode
1976  * @client: Handle to slave device
1977  * @buf: Data that will be written to the slave
1978  * @count: How many bytes to write, must be less than 64k since msg.len is u16
1979  *
1980  * Returns negative errno, or else the number of bytes written.
1981  */
1982 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1983 {
1984         int ret;
1985         struct i2c_adapter *adap = client->adapter;
1986         struct i2c_msg msg;
1987
1988         msg.addr = client->addr;
1989         msg.flags = client->flags & I2C_M_TEN;
1990         msg.len = count;
1991         msg.buf = (char *)buf;
1992
1993         ret = i2c_transfer(adap, &msg, 1);
1994
1995         /*
1996          * If everything went ok (i.e. 1 msg transmitted), return #bytes
1997          * transmitted, else error code.
1998          */
1999         return (ret == 1) ? count : ret;
2000 }
2001 EXPORT_SYMBOL(i2c_master_send);
2002
2003 /**
2004  * i2c_master_recv - issue a single I2C message in master receive mode
2005  * @client: Handle to slave device
2006  * @buf: Where to store data read from slave
2007  * @count: How many bytes to read, must be less than 64k since msg.len is u16
2008  *
2009  * Returns negative errno, or else the number of bytes read.
2010  */
2011 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
2012 {
2013         struct i2c_adapter *adap = client->adapter;
2014         struct i2c_msg msg;
2015         int ret;
2016
2017         msg.addr = client->addr;
2018         msg.flags = client->flags & I2C_M_TEN;
2019         msg.flags |= I2C_M_RD;
2020         msg.len = count;
2021         msg.buf = buf;
2022
2023         ret = i2c_transfer(adap, &msg, 1);
2024
2025         /*
2026          * If everything went ok (i.e. 1 msg received), return #bytes received,
2027          * else error code.
2028          */
2029         return (ret == 1) ? count : ret;
2030 }
2031 EXPORT_SYMBOL(i2c_master_recv);
2032
2033 /* ----------------------------------------------------
2034  * the i2c address scanning function
2035  * Will not work for 10-bit addresses!
2036  * ----------------------------------------------------
2037  */
2038
2039 /*
2040  * Legacy default probe function, mostly relevant for SMBus. The default
2041  * probe method is a quick write, but it is known to corrupt the 24RF08
2042  * EEPROMs due to a state machine bug, and could also irreversibly
2043  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2044  * we use a short byte read instead. Also, some bus drivers don't implement
2045  * quick write, so we fallback to a byte read in that case too.
2046  * On x86, there is another special case for FSC hardware monitoring chips,
2047  * which want regular byte reads (address 0x73.) Fortunately, these are the
2048  * only known chips using this I2C address on PC hardware.
2049  * Returns 1 if probe succeeded, 0 if not.
2050  */
2051 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2052 {
2053         int err;
2054         union i2c_smbus_data dummy;
2055
2056 #ifdef CONFIG_X86
2057         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2058          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2059                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2060                                      I2C_SMBUS_BYTE_DATA, &dummy);
2061         else
2062 #endif
2063         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2064          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2065                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2066                                      I2C_SMBUS_QUICK, NULL);
2067         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2068                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2069                                      I2C_SMBUS_BYTE, &dummy);
2070         else {
2071                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2072                          addr);
2073                 err = -EOPNOTSUPP;
2074         }
2075
2076         return err >= 0;
2077 }
2078
2079 static int i2c_detect_address(struct i2c_client *temp_client,
2080                               struct i2c_driver *driver)
2081 {
2082         struct i2c_board_info info;
2083         struct i2c_adapter *adapter = temp_client->adapter;
2084         int addr = temp_client->addr;
2085         int err;
2086
2087         /* Make sure the address is valid */
2088         err = i2c_check_7bit_addr_validity_strict(addr);
2089         if (err) {
2090                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2091                          addr);
2092                 return err;
2093         }
2094
2095         /* Skip if already in use (7 bit, no need to encode flags) */
2096         if (i2c_check_addr_busy(adapter, addr))
2097                 return 0;
2098
2099         /* Make sure there is something at this address */
2100         if (!i2c_default_probe(adapter, addr))
2101                 return 0;
2102
2103         /* Finally call the custom detection function */
2104         memset(&info, 0, sizeof(struct i2c_board_info));
2105         info.addr = addr;
2106         err = driver->detect(temp_client, &info);
2107         if (err) {
2108                 /* -ENODEV is returned if the detection fails. We catch it
2109                    here as this isn't an error. */
2110                 return err == -ENODEV ? 0 : err;
2111         }
2112
2113         /* Consistency check */
2114         if (info.type[0] == '\0') {
2115                 dev_err(&adapter->dev,
2116                         "%s detection function provided no name for 0x%x\n",
2117                         driver->driver.name, addr);
2118         } else {
2119                 struct i2c_client *client;
2120
2121                 /* Detection succeeded, instantiate the device */
2122                 if (adapter->class & I2C_CLASS_DEPRECATED)
2123                         dev_warn(&adapter->dev,
2124                                 "This adapter will soon drop class based instantiation of devices. "
2125                                 "Please make sure client 0x%02x gets instantiated by other means. "
2126                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2127                                 info.addr);
2128
2129                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2130                         info.type, info.addr);
2131                 client = i2c_new_device(adapter, &info);
2132                 if (client)
2133                         list_add_tail(&client->detected, &driver->clients);
2134                 else
2135                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2136                                 info.type, info.addr);
2137         }
2138         return 0;
2139 }
2140
2141 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2142 {
2143         const unsigned short *address_list;
2144         struct i2c_client *temp_client;
2145         int i, err = 0;
2146         int adap_id = i2c_adapter_id(adapter);
2147
2148         address_list = driver->address_list;
2149         if (!driver->detect || !address_list)
2150                 return 0;
2151
2152         /* Warn that the adapter lost class based instantiation */
2153         if (adapter->class == I2C_CLASS_DEPRECATED) {
2154                 dev_dbg(&adapter->dev,
2155                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2156                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2157                         driver->driver.name);
2158                 return 0;
2159         }
2160
2161         /* Stop here if the classes do not match */
2162         if (!(adapter->class & driver->class))
2163                 return 0;
2164
2165         /* Set up a temporary client to help detect callback */
2166         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2167         if (!temp_client)
2168                 return -ENOMEM;
2169         temp_client->adapter = adapter;
2170
2171         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2172                 dev_dbg(&adapter->dev,
2173                         "found normal entry for adapter %d, addr 0x%02x\n",
2174                         adap_id, address_list[i]);
2175                 temp_client->addr = address_list[i];
2176                 err = i2c_detect_address(temp_client, driver);
2177                 if (unlikely(err))
2178                         break;
2179         }
2180
2181         kfree(temp_client);
2182         return err;
2183 }
2184
2185 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2186 {
2187         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2188                               I2C_SMBUS_QUICK, NULL) >= 0;
2189 }
2190 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2191
2192 struct i2c_client *
2193 i2c_new_probed_device(struct i2c_adapter *adap,
2194                       struct i2c_board_info *info,
2195                       unsigned short const *addr_list,
2196                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2197 {
2198         int i;
2199
2200         if (!probe)
2201                 probe = i2c_default_probe;
2202
2203         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2204                 /* Check address validity */
2205                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2206                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2207                                  addr_list[i]);
2208                         continue;
2209                 }
2210
2211                 /* Check address availability (7 bit, no need to encode flags) */
2212                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2213                         dev_dbg(&adap->dev,
2214                                 "Address 0x%02x already in use, not probing\n",
2215                                 addr_list[i]);
2216                         continue;
2217                 }
2218
2219                 /* Test address responsiveness */
2220                 if (probe(adap, addr_list[i]))
2221                         break;
2222         }
2223
2224         if (addr_list[i] == I2C_CLIENT_END) {
2225                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2226                 return NULL;
2227         }
2228
2229         info->addr = addr_list[i];
2230         return i2c_new_device(adap, info);
2231 }
2232 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2233
2234 struct i2c_adapter *i2c_get_adapter(int nr)
2235 {
2236         struct i2c_adapter *adapter;
2237
2238         mutex_lock(&core_lock);
2239         adapter = idr_find(&i2c_adapter_idr, nr);
2240         if (!adapter)
2241                 goto exit;
2242
2243         if (try_module_get(adapter->owner))
2244                 get_device(&adapter->dev);
2245         else
2246                 adapter = NULL;
2247
2248  exit:
2249         mutex_unlock(&core_lock);
2250         return adapter;
2251 }
2252 EXPORT_SYMBOL(i2c_get_adapter);
2253
2254 void i2c_put_adapter(struct i2c_adapter *adap)
2255 {
2256         if (!adap)
2257                 return;
2258
2259         put_device(&adap->dev);
2260         module_put(adap->owner);
2261 }
2262 EXPORT_SYMBOL(i2c_put_adapter);
2263
2264 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2265 MODULE_DESCRIPTION("I2C-Bus main module");
2266 MODULE_LICENSE("GPL");