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;
 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                         irq = i2c_smbus_host_notify_to_irq(client);
 331                 } else if (dev->of_node) {
 332                         irq = of_irq_get_byname(dev->of_node, "irq");
 333                         if (irq == -EINVAL || irq == -ENODATA)
 334                                 irq = of_irq_get(dev->of_node, 0);
 335                 } else if (ACPI_COMPANION(dev)) {
 336                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 337                 }
 338                 if (irq == -EPROBE_DEFER)
 339                         return irq;
 340
 341                 if (irq < 0)
 342                         irq = 0;
 343
 344                 client->irq = irq;
 345         }
 346
 347         /*
 348          * An I2C ID table is not mandatory, if and only if, a suitable OF
 349          * or ACPI ID table is supplied for the probing device.
 350          */
 351         if (!driver->id_table &&
 352             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 353             !i2c_of_match_device(dev->driver->of_match_table, client))
 354                 return -ENODEV;
 355
 356         if (client->flags & I2C_CLIENT_WAKE) {
 357                 int wakeirq = -ENOENT;
 358
 359                 if (dev->of_node) {
 360                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 361                         if (wakeirq == -EPROBE_DEFER)
 362                                 return wakeirq;
 363                 }
 364
 365                 device_init_wakeup(&client->dev, true);
 366
 367                 if (wakeirq > 0 && wakeirq != client->irq)
 368                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 369                 else if (client->irq > 0)
 370                         status = dev_pm_set_wake_irq(dev, client->irq);
 371                 else
 372                         status = 0;
 373
 374                 if (status)
 375                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 376         }
 377
 378         dev_dbg(dev, "probe\n");
 379
 380         status = of_clk_set_defaults(dev->of_node, false);
 381         if (status < 0)
 382                 goto err_clear_wakeup_irq;
 383
 384         status = dev_pm_domain_attach(&client->dev, true);
 385         if (status)
 386                 goto err_clear_wakeup_irq;
 387
 388         /*
 389          * When there are no more users of probe(),
 390          * rename probe_new to probe.
 391          */
 392         if (driver->probe_new)
 393                 status = driver->probe_new(client);
 394         else if (driver->probe)
 395                 status = driver->probe(client,
 396                                        i2c_match_id(driver->id_table, client));
 397         else
 398                 status = -EINVAL;
 399
 400         if (status)
 401                 goto err_detach_pm_domain;
 402
 403         return 0;
 404
 405 err_detach_pm_domain:
 406         dev_pm_domain_detach(&client->dev, true);
 407 err_clear_wakeup_irq:
 408         dev_pm_clear_wake_irq(&client->dev);
 409         device_init_wakeup(&client->dev, false);
 410         return status;
 411 }
 412
 413 static int i2c_device_remove(struct device *dev)
 414 {
 415         struct i2c_client       *client = i2c_verify_client(dev);
 416         struct i2c_driver       *driver;
 417         int status = 0;
 418
 419         if (!client || !dev->driver)
 420                 return 0;
 421
 422         driver = to_i2c_driver(dev->driver);
 423         if (driver->remove) {
 424                 dev_dbg(dev, "remove\n");
 425                 status = driver->remove(client);
 426         }
 427
 428         dev_pm_domain_detach(&client->dev, true);
 429
 430         dev_pm_clear_wake_irq(&client->dev);
 431         device_init_wakeup(&client->dev, false);
 432
 433         client->irq = client->init_irq;
 434
 435         return status;
 436 }
 437
 438 static void i2c_device_shutdown(struct device *dev)
 439 {
 440         struct i2c_client *client = i2c_verify_client(dev);
 441         struct i2c_driver *driver;
 442
 443         if (!client || !dev->driver)
 444                 return;
 445         driver = to_i2c_driver(dev->driver);
 446         if (driver->shutdown)
 447                 driver->shutdown(client);
 448 }
 449
 450 static void i2c_client_dev_release(struct device *dev)
 451 {
 452         kfree(to_i2c_client(dev));
 453 }
 454
 455 static ssize_t
 456 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 457 {
 458         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 459                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 460 }
 461 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 462
 463 static ssize_t
 464 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 465 {
 466         struct i2c_client *client = to_i2c_client(dev);
 467         int len;
 468
 469         len = of_device_modalias(dev, buf, PAGE_SIZE);
 470         if (len != -ENODEV)
 471                 return len;
 472
 473         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 474         if (len != -ENODEV)
 475                 return len;
 476
 477         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 478 }
 479 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 480
 481 static struct attribute *i2c_dev_attrs[] = {
 482         &dev_attr_name.attr,
 483         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 484         &dev_attr_modalias.attr,
 485         NULL
 486 };
 487 ATTRIBUTE_GROUPS(i2c_dev);
 488
 489 struct bus_type i2c_bus_type = {
 490         .name           = "i2c",
 491         .match          = i2c_device_match,
 492         .probe          = i2c_device_probe,
 493         .remove         = i2c_device_remove,
 494         .shutdown       = i2c_device_shutdown,
 495 };
 496 EXPORT_SYMBOL_GPL(i2c_bus_type);
 497
 498 struct device_type i2c_client_type = {
 499         .groups         = i2c_dev_groups,
 500         .uevent         = i2c_device_uevent,
 501         .release        = i2c_client_dev_release,
 502 };
 503 EXPORT_SYMBOL_GPL(i2c_client_type);
 504
 505
 506 /**
 507  * i2c_verify_client - return parameter as i2c_client, or NULL
 508  * @dev: device, probably from some driver model iterator
 509  *
 510  * When traversing the driver model tree, perhaps using driver model
 511  * iterators like @device_for_each_child(), you can't assume very much
 512  * about the nodes you find.  Use this function to avoid oopses caused
 513  * by wrongly treating some non-I2C device as an i2c_client.
 514  */
 515 struct i2c_client *i2c_verify_client(struct device *dev)
 516 {
 517         return (dev->type == &i2c_client_type)
 518                         ? to_i2c_client(dev)
 519                         : NULL;
 520 }
 521 EXPORT_SYMBOL(i2c_verify_client);
 522
 523
 524 /* Return a unique address which takes the flags of the client into account */
 525 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 526 {
 527         unsigned short addr = client->addr;
 528
 529         /* For some client flags, add an arbitrary offset to avoid collisions */
 530         if (client->flags & I2C_CLIENT_TEN)
 531                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 532
 533         if (client->flags & I2C_CLIENT_SLAVE)
 534                 addr |= I2C_ADDR_OFFSET_SLAVE;
 535
 536         return addr;
 537 }
 538
 539 /* This is a permissive address validity check, I2C address map constraints
 540  * are purposely not enforced, except for the general call address. */
 541 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 542 {
 543         if (flags & I2C_CLIENT_TEN) {
 544                 /* 10-bit address, all values are valid */
 545                 if (addr > 0x3ff)
 546                         return -EINVAL;
 547         } else {
 548                 /* 7-bit address, reject the general call address */
 549                 if (addr == 0x00 || addr > 0x7f)
 550                         return -EINVAL;
 551         }
 552         return 0;
 553 }
 554
 555 /* And this is a strict address validity check, used when probing. If a
 556  * device uses a reserved address, then it shouldn't be probed. 7-bit
 557  * addressing is assumed, 10-bit address devices are rare and should be
 558  * explicitly enumerated. */
 559 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 560 {
 561         /*
 562          * Reserved addresses per I2C specification:
 563          *  0x00       General call address / START byte
 564          *  0x01       CBUS address
 565          *  0x02       Reserved for different bus format
 566          *  0x03       Reserved for future purposes
 567          *  0x04-0x07  Hs-mode master code
 568          *  0x78-0x7b  10-bit slave addressing
 569          *  0x7c-0x7f  Reserved for future purposes
 570          */
 571         if (addr < 0x08 || addr > 0x77)
 572                 return -EINVAL;
 573         return 0;
 574 }
 575
 576 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 577 {
 578         struct i2c_client       *client = i2c_verify_client(dev);
 579         int                     addr = *(int *)addrp;
 580
 581         if (client && i2c_encode_flags_to_addr(client) == addr)
 582                 return -EBUSY;
 583         return 0;
 584 }
 585
 586 /* walk up mux tree */
 587 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 588 {
 589         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 590         int result;
 591
 592         result = device_for_each_child(&adapter->dev, &addr,
 593                                         __i2c_check_addr_busy);
 594
 595         if (!result && parent)
 596                 result = i2c_check_mux_parents(parent, addr);
 597
 598         return result;
 599 }
 600
 601 /* recurse down mux tree */
 602 static int i2c_check_mux_children(struct device *dev, void *addrp)
 603 {
 604         int result;
 605
 606         if (dev->type == &i2c_adapter_type)
 607                 result = device_for_each_child(dev, addrp,
 608                                                 i2c_check_mux_children);
 609         else
 610                 result = __i2c_check_addr_busy(dev, addrp);
 611
 612         return result;
 613 }
 614
 615 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 616 {
 617         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 618         int result = 0;
 619
 620         if (parent)
 621                 result = i2c_check_mux_parents(parent, addr);
 622
 623         if (!result)
 624                 result = device_for_each_child(&adapter->dev, &addr,
 625                                                 i2c_check_mux_children);
 626
 627         return result;
 628 }
 629
 630 /**
 631  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 632  * @adapter: Target I2C bus segment
 633  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 634  *      locks only this branch in the adapter tree
 635  */
 636 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 637                                  unsigned int flags)
 638 {
 639         rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 640 }
 641
 642 /**
 643  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 644  * @adapter: Target I2C bus segment
 645  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 646  *      trylocks only this branch in the adapter tree
 647  */
 648 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 649                                    unsigned int flags)
 650 {
 651         return rt_mutex_trylock(&adapter->bus_lock);
 652 }
 653
 654 /**
 655  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 656  * @adapter: Target I2C bus segment
 657  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 658  *      unlocks only this branch in the adapter tree
 659  */
 660 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 661                                    unsigned int flags)
 662 {
 663         rt_mutex_unlock(&adapter->bus_lock);
 664 }
 665
 666 static void i2c_dev_set_name(struct i2c_adapter *adap,
 667                              struct i2c_client *client,
 668                              struct i2c_board_info const *info)
 669 {
 670         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 671
 672         if (info && info->dev_name) {
 673                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 674                 return;
 675         }
 676
 677         if (adev) {
 678                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 679                 return;
 680         }
 681
 682         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 683                      i2c_encode_flags_to_addr(client));
 684 }
 685
 686 static int i2c_dev_irq_from_resources(const struct resource *resources,
 687                                       unsigned int num_resources)
 688 {
 689         struct irq_data *irqd;
 690         int i;
 691
 692         for (i = 0; i < num_resources; i++) {
 693                 const struct resource *r = &resources[i];
 694
 695                 if (resource_type(r) != IORESOURCE_IRQ)
 696                         continue;
 697
 698                 if (r->flags & IORESOURCE_BITS) {
 699                         irqd = irq_get_irq_data(r->start);
 700                         if (!irqd)
 701                                 break;
 702
 703                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 704                 }
 705
 706                 return r->start;
 707         }
 708
 709         return 0;
 710 }
 711
 712 /**
 713  * i2c_new_device - instantiate an i2c device
 714  * @adap: the adapter managing the device
 715  * @info: describes one I2C device; bus_num is ignored
 716  * Context: can sleep
 717  *
 718  * Create an i2c device. Binding is handled through driver model
 719  * probe()/remove() methods.  A driver may be bound to this device when we
 720  * return from this function, or any later moment (e.g. maybe hotplugging will
 721  * load the driver module).  This call is not appropriate for use by mainboard
 722  * initialization logic, which usually runs during an arch_initcall() long
 723  * before any i2c_adapter could exist.
 724  *
 725  * This returns the new i2c client, which may be saved for later use with
 726  * i2c_unregister_device(); or NULL to indicate an error.
 727  */
 728 struct i2c_client *
 729 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 730 {
 731         struct i2c_client       *client;
 732         int                     status;
 733
 734         client = kzalloc(sizeof *client, GFP_KERNEL);
 735         if (!client)
 736                 return NULL;
 737
 738         client->adapter = adap;
 739
 740         client->dev.platform_data = info->platform_data;
 741         client->flags = info->flags;
 742         client->addr = info->addr;
 743
 744         client->init_irq = info->irq;
 745         if (!client->init_irq)
 746                 client->init_irq = i2c_dev_irq_from_resources(info->resources,
 747                                                          info->num_resources);
 748         client->irq = client->init_irq;
 749
 750         strlcpy(client->name, info->type, sizeof(client->name));
 751
 752         status = i2c_check_addr_validity(client->addr, client->flags);
 753         if (status) {
 754                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 755                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 756                 goto out_err_silent;
 757         }
 758
 759         /* Check for address business */
 760         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 761         if (status)
 762                 goto out_err;
 763
 764         client->dev.parent = &client->adapter->dev;
 765         client->dev.bus = &i2c_bus_type;
 766         client->dev.type = &i2c_client_type;
 767         client->dev.of_node = of_node_get(info->of_node);
 768         client->dev.fwnode = info->fwnode;
 769
 770         i2c_dev_set_name(adap, client, info);
 771
 772         if (info->properties) {
 773                 status = device_add_properties(&client->dev, info->properties);
 774                 if (status) {
 775                         dev_err(&adap->dev,
 776                                 "Failed to add properties to client %s: %d\n",
 777                                 client->name, status);
 778                         goto out_err_put_of_node;
 779                 }
 780         }
 781
 782         status = device_register(&client->dev);
 783         if (status)
 784                 goto out_free_props;
 785
 786         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 787                 client->name, dev_name(&client->dev));
 788
 789         return client;
 790
 791 out_free_props:
 792         if (info->properties)
 793                 device_remove_properties(&client->dev);
 794 out_err_put_of_node:
 795         of_node_put(info->of_node);
 796 out_err:
 797         dev_err(&adap->dev,
 798                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 799                 client->name, client->addr, status);
 800 out_err_silent:
 801         kfree(client);
 802         return NULL;
 803 }
 804 EXPORT_SYMBOL_GPL(i2c_new_device);
 805
 806
 807 /**
 808  * i2c_unregister_device - reverse effect of i2c_new_device()
 809  * @client: value returned from i2c_new_device()
 810  * Context: can sleep
 811  */
 812 void i2c_unregister_device(struct i2c_client *client)
 813 {
 814         if (!client)
 815                 return;
 816
 817         if (client->dev.of_node) {
 818                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 819                 of_node_put(client->dev.of_node);
 820         }
 821
 822         if (ACPI_COMPANION(&client->dev))
 823                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 824         device_unregister(&client->dev);
 825 }
 826 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 827
 828
 829 static const struct i2c_device_id dummy_id[] = {
 830         { "dummy", 0 },
 831         { },
 832 };
 833
 834 static int dummy_probe(struct i2c_client *client,
 835                        const struct i2c_device_id *id)
 836 {
 837         return 0;
 838 }
 839
 840 static int dummy_remove(struct i2c_client *client)
 841 {
 842         return 0;
 843 }
 844
 845 static struct i2c_driver dummy_driver = {
 846         .driver.name    = "dummy",
 847         .probe          = dummy_probe,
 848         .remove         = dummy_remove,
 849         .id_table       = dummy_id,
 850 };
 851
 852 /**
 853  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 854  * @adapter: the adapter managing the device
 855  * @address: seven bit address to be used
 856  * Context: can sleep
 857  *
 858  * This returns an I2C client bound to the "dummy" driver, intended for use
 859  * with devices that consume multiple addresses.  Examples of such chips
 860  * include various EEPROMS (like 24c04 and 24c08 models).
 861  *
 862  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 863  * except i2c_transfer() need a client handle; the dummy will be that handle.
 864  * And second, this prevents the specified address from being bound to a
 865  * different driver.
 866  *
 867  * This returns the new i2c client, which should be saved for later use with
 868  * i2c_unregister_device(); or NULL to indicate an error.
 869  */
 870 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 871 {
 872         struct i2c_board_info info = {
 873                 I2C_BOARD_INFO("dummy", address),
 874         };
 875
 876         return i2c_new_device(adapter, &info);
 877 }
 878 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 879
 880 /**
 881  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 882  * and create the associated device
 883  * @client: Handle to the primary client
 884  * @name: Handle to specify which secondary address to get
 885  * @default_addr: Used as a fallback if no secondary address was specified
 886  * Context: can sleep
 887  *
 888  * I2C clients can be composed of multiple I2C slaves bound together in a single
 889  * component. The I2C client driver then binds to the master I2C slave and needs
 890  * to create I2C dummy clients to communicate with all the other slaves.
 891  *
 892  * This function creates and returns an I2C dummy client whose I2C address is
 893  * retrieved from the platform firmware based on the given slave name. If no
 894  * address is specified by the firmware default_addr is used.
 895  *
 896  * On DT-based platforms the address is retrieved from the "reg" property entry
 897  * cell whose "reg-names" value matches the slave name.
 898  *
 899  * This returns the new i2c client, which should be saved for later use with
 900  * i2c_unregister_device(); or NULL to indicate an error.
 901  */
 902 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 903                                                 const char *name,
 904                                                 u16 default_addr)
 905 {
 906         struct device_node *np = client->dev.of_node;
 907         u32 addr = default_addr;
 908         int i;
 909
 910         if (np) {
 911                 i = of_property_match_string(np, "reg-names", name);
 912                 if (i >= 0)
 913                         of_property_read_u32_index(np, "reg", i, &addr);
 914         }
 915
 916         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 917         return i2c_new_dummy(client->adapter, addr);
 918 }
 919 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 920
 921 /* ------------------------------------------------------------------------- */
 922
 923 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 924
 925 static void i2c_adapter_dev_release(struct device *dev)
 926 {
 927         struct i2c_adapter *adap = to_i2c_adapter(dev);
 928         complete(&adap->dev_released);
 929 }
 930
 931 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 932 {
 933         unsigned int depth = 0;
 934
 935         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 936                 depth++;
 937
 938         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 939                   "adapter depth exceeds lockdep subclass limit\n");
 940
 941         return depth;
 942 }
 943 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 944
 945 /*
 946  * Let users instantiate I2C devices through sysfs. This can be used when
 947  * platform initialization code doesn't contain the proper data for
 948  * whatever reason. Also useful for drivers that do device detection and
 949  * detection fails, either because the device uses an unexpected address,
 950  * or this is a compatible device with different ID register values.
 951  *
 952  * Parameter checking may look overzealous, but we really don't want
 953  * the user to provide incorrect parameters.
 954  */
 955 static ssize_t
 956 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 957                      const char *buf, size_t count)
 958 {
 959         struct i2c_adapter *adap = to_i2c_adapter(dev);
 960         struct i2c_board_info info;
 961         struct i2c_client *client;
 962         char *blank, end;
 963         int res;
 964
 965         memset(&info, 0, sizeof(struct i2c_board_info));
 966
 967         blank = strchr(buf, ' ');
 968         if (!blank) {
 969                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 970                 return -EINVAL;
 971         }
 972         if (blank - buf > I2C_NAME_SIZE - 1) {
 973                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 974                 return -EINVAL;
 975         }
 976         memcpy(info.type, buf, blank - buf);
 977
 978         /* Parse remaining parameters, reject extra parameters */
 979         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 980         if (res < 1) {
 981                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 982                 return -EINVAL;
 983         }
 984         if (res > 1  && end != '\n') {
 985                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 986                 return -EINVAL;
 987         }
 988
 989         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 990                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 991                 info.flags |= I2C_CLIENT_TEN;
 992         }
 993
 994         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 995                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 996                 info.flags |= I2C_CLIENT_SLAVE;
 997         }
 998
 999         client = i2c_new_device(adap, &info);
1000         if (!client)
1001                 return -EINVAL;
1002
1003         /* Keep track of the added device */
1004         mutex_lock(&adap->userspace_clients_lock);
1005         list_add_tail(&client->detected, &adap->userspace_clients);
1006         mutex_unlock(&adap->userspace_clients_lock);
1007         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1008                  info.type, info.addr);
1009
1010         return count;
1011 }
1012 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1013
1014 /*
1015  * And of course let the users delete the devices they instantiated, if
1016  * they got it wrong. This interface can only be used to delete devices
1017  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1018  * don't delete devices to which some kernel code still has references.
1019  *
1020  * Parameter checking may look overzealous, but we really don't want
1021  * the user to delete the wrong device.
1022  */
1023 static ssize_t
1024 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1025                         const char *buf, size_t count)
1026 {
1027         struct i2c_adapter *adap = to_i2c_adapter(dev);
1028         struct i2c_client *client, *next;
1029         unsigned short addr;
1030         char end;
1031         int res;
1032
1033         /* Parse parameters, reject extra parameters */
1034         res = sscanf(buf, "%hi%c", &addr, &end);
1035         if (res < 1) {
1036                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1037                 return -EINVAL;
1038         }
1039         if (res > 1  && end != '\n') {
1040                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1041                 return -EINVAL;
1042         }
1043
1044         /* Make sure the device was added through sysfs */
1045         res = -ENOENT;
1046         mutex_lock_nested(&adap->userspace_clients_lock,
1047                           i2c_adapter_depth(adap));
1048         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1049                                  detected) {
1050                 if (i2c_encode_flags_to_addr(client) == addr) {
1051                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1052                                  "delete_device", client->name, client->addr);
1053
1054                         list_del(&client->detected);
1055                         i2c_unregister_device(client);
1056                         res = count;
1057                         break;
1058                 }
1059         }
1060         mutex_unlock(&adap->userspace_clients_lock);
1061
1062         if (res < 0)
1063                 dev_err(dev, "%s: Can't find device in list\n",
1064                         "delete_device");
1065         return res;
1066 }
1067 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1068                                    i2c_sysfs_delete_device);
1069
1070 static struct attribute *i2c_adapter_attrs[] = {
1071         &dev_attr_name.attr,
1072         &dev_attr_new_device.attr,
1073         &dev_attr_delete_device.attr,
1074         NULL
1075 };
1076 ATTRIBUTE_GROUPS(i2c_adapter);
1077
1078 struct device_type i2c_adapter_type = {
1079         .groups         = i2c_adapter_groups,
1080         .release        = i2c_adapter_dev_release,
1081 };
1082 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1083
1084 /**
1085  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1086  * @dev: device, probably from some driver model iterator
1087  *
1088  * When traversing the driver model tree, perhaps using driver model
1089  * iterators like @device_for_each_child(), you can't assume very much
1090  * about the nodes you find.  Use this function to avoid oopses caused
1091  * by wrongly treating some non-I2C device as an i2c_adapter.
1092  */
1093 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1094 {
1095         return (dev->type == &i2c_adapter_type)
1096                         ? to_i2c_adapter(dev)
1097                         : NULL;
1098 }
1099 EXPORT_SYMBOL(i2c_verify_adapter);
1100
1101 #ifdef CONFIG_I2C_COMPAT
1102 static struct class_compat *i2c_adapter_compat_class;
1103 #endif
1104
1105 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1106 {
1107         struct i2c_devinfo      *devinfo;
1108
1109         down_read(&__i2c_board_lock);
1110         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1111                 if (devinfo->busnum == adapter->nr
1112                                 && !i2c_new_device(adapter,
1113                                                 &devinfo->board_info))
1114                         dev_err(&adapter->dev,
1115                                 "Can't create device at 0x%02x\n",
1116                                 devinfo->board_info.addr);
1117         }
1118         up_read(&__i2c_board_lock);
1119 }
1120
1121 static int i2c_do_add_adapter(struct i2c_driver *driver,
1122                               struct i2c_adapter *adap)
1123 {
1124         /* Detect supported devices on that bus, and instantiate them */
1125         i2c_detect(adap, driver);
1126
1127         return 0;
1128 }
1129
1130 static int __process_new_adapter(struct device_driver *d, void *data)
1131 {
1132         return i2c_do_add_adapter(to_i2c_driver(d), data);
1133 }
1134
1135 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1136         .lock_bus =    i2c_adapter_lock_bus,
1137         .trylock_bus = i2c_adapter_trylock_bus,
1138         .unlock_bus =  i2c_adapter_unlock_bus,
1139 };
1140
1141 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1142 {
1143         struct irq_domain *domain = adap->host_notify_domain;
1144         irq_hw_number_t hwirq;
1145
1146         if (!domain)
1147                 return;
1148
1149         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1150                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1151
1152         irq_domain_remove(domain);
1153         adap->host_notify_domain = NULL;
1154 }
1155
1156 static int i2c_host_notify_irq_map(struct irq_domain *h,
1157                                           unsigned int virq,
1158                                           irq_hw_number_t hw_irq_num)
1159 {
1160         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1161
1162         return 0;
1163 }
1164
1165 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1166         .map = i2c_host_notify_irq_map,
1167 };
1168
1169 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1170 {
1171         struct irq_domain *domain;
1172
1173         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1174                 return 0;
1175
1176         domain = irq_domain_create_linear(adap->dev.fwnode,
1177                                           I2C_ADDR_7BITS_COUNT,
1178                                           &i2c_host_notify_irq_ops, adap);
1179         if (!domain)
1180                 return -ENOMEM;
1181
1182         adap->host_notify_domain = domain;
1183
1184         return 0;
1185 }
1186
1187 /**
1188  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1189  * I2C client.
1190  * @adap: the adapter
1191  * @addr: the I2C address of the notifying device
1192  * Context: can't sleep
1193  *
1194  * Helper function to be called from an I2C bus driver's interrupt
1195  * handler. It will schedule the Host Notify IRQ.
1196  */
1197 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1198 {
1199         int irq;
1200
1201         if (!adap)
1202                 return -EINVAL;
1203
1204         irq = irq_find_mapping(adap->host_notify_domain, addr);
1205         if (irq <= 0)
1206                 return -ENXIO;
1207
1208         generic_handle_irq(irq);
1209
1210         return 0;
1211 }
1212 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1213
1214 static int i2c_register_adapter(struct i2c_adapter *adap)
1215 {
1216         int res = -EINVAL;
1217
1218         /* Can't register until after driver model init */
1219         if (WARN_ON(!is_registered)) {
1220                 res = -EAGAIN;
1221                 goto out_list;
1222         }
1223
1224         /* Sanity checks */
1225         if (WARN(!adap->name[0], "i2c adapter has no name"))
1226                 goto out_list;
1227
1228         if (!adap->algo) {
1229                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1230                 goto out_list;
1231         }
1232
1233         if (!adap->lock_ops)
1234                 adap->lock_ops = &i2c_adapter_lock_ops;
1235
1236         adap->locked_flags = 0;
1237         rt_mutex_init(&adap->bus_lock);
1238         rt_mutex_init(&adap->mux_lock);
1239         mutex_init(&adap->userspace_clients_lock);
1240         INIT_LIST_HEAD(&adap->userspace_clients);
1241
1242         /* Set default timeout to 1 second if not already set */
1243         if (adap->timeout == 0)
1244                 adap->timeout = HZ;
1245
1246         /* register soft irqs for Host Notify */
1247         res = i2c_setup_host_notify_irq_domain(adap);
1248         if (res) {
1249                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1250                        adap->name, res);
1251                 goto out_list;
1252         }
1253
1254         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1255         adap->dev.bus = &i2c_bus_type;
1256         adap->dev.type = &i2c_adapter_type;
1257         res = device_register(&adap->dev);
1258         if (res) {
1259                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1260                 goto out_list;
1261         }
1262
1263         res = of_i2c_setup_smbus_alert(adap);
1264         if (res)
1265                 goto out_reg;
1266
1267         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1268
1269         pm_runtime_no_callbacks(&adap->dev);
1270         pm_suspend_ignore_children(&adap->dev, true);
1271         pm_runtime_enable(&adap->dev);
1272
1273 #ifdef CONFIG_I2C_COMPAT
1274         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1275                                        adap->dev.parent);
1276         if (res)
1277                 dev_warn(&adap->dev,
1278                          "Failed to create compatibility class link\n");
1279 #endif
1280
1281         i2c_init_recovery(adap);
1282
1283         /* create pre-declared device nodes */
1284         of_i2c_register_devices(adap);
1285         i2c_acpi_register_devices(adap);
1286         i2c_acpi_install_space_handler(adap);
1287
1288         if (adap->nr < __i2c_first_dynamic_bus_num)
1289                 i2c_scan_static_board_info(adap);
1290
1291         /* Notify drivers */
1292         mutex_lock(&core_lock);
1293         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1294         mutex_unlock(&core_lock);
1295
1296         return 0;
1297
1298 out_reg:
1299         init_completion(&adap->dev_released);
1300         device_unregister(&adap->dev);
1301         wait_for_completion(&adap->dev_released);
1302 out_list:
1303         mutex_lock(&core_lock);
1304         idr_remove(&i2c_adapter_idr, adap->nr);
1305         mutex_unlock(&core_lock);
1306         return res;
1307 }
1308
1309 /**
1310  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1311  * @adap: the adapter to register (with adap->nr initialized)
1312  * Context: can sleep
1313  *
1314  * See i2c_add_numbered_adapter() for details.
1315  */
1316 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1317 {
1318         int id;
1319
1320         mutex_lock(&core_lock);
1321         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1322         mutex_unlock(&core_lock);
1323         if (WARN(id < 0, "couldn't get idr"))
1324                 return id == -ENOSPC ? -EBUSY : id;
1325
1326         return i2c_register_adapter(adap);
1327 }
1328
1329 /**
1330  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1331  * @adapter: the adapter to add
1332  * Context: can sleep
1333  *
1334  * This routine is used to declare an I2C adapter when its bus number
1335  * doesn't matter or when its bus number is specified by an dt alias.
1336  * Examples of bases when the bus number doesn't matter: I2C adapters
1337  * dynamically added by USB links or PCI plugin cards.
1338  *
1339  * When this returns zero, a new bus number was allocated and stored
1340  * in adap->nr, and the specified adapter became available for clients.
1341  * Otherwise, a negative errno value is returned.
1342  */
1343 int i2c_add_adapter(struct i2c_adapter *adapter)
1344 {
1345         struct device *dev = &adapter->dev;
1346         int id;
1347
1348         if (dev->of_node) {
1349                 id = of_alias_get_id(dev->of_node, "i2c");
1350                 if (id >= 0) {
1351                         adapter->nr = id;
1352                         return __i2c_add_numbered_adapter(adapter);
1353                 }
1354         }
1355
1356         mutex_lock(&core_lock);
1357         id = idr_alloc(&i2c_adapter_idr, adapter,
1358                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1359         mutex_unlock(&core_lock);
1360         if (WARN(id < 0, "couldn't get idr"))
1361                 return id;
1362
1363         adapter->nr = id;
1364
1365         return i2c_register_adapter(adapter);
1366 }
1367 EXPORT_SYMBOL(i2c_add_adapter);
1368
1369 /**
1370  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1371  * @adap: the adapter to register (with adap->nr initialized)
1372  * Context: can sleep
1373  *
1374  * This routine is used to declare an I2C adapter when its bus number
1375  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1376  * or otherwise built in to the system's mainboard, and where i2c_board_info
1377  * is used to properly configure I2C devices.
1378  *
1379  * If the requested bus number is set to -1, then this function will behave
1380  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1381  *
1382  * If no devices have pre-been declared for this bus, then be sure to
1383  * register the adapter before any dynamically allocated ones.  Otherwise
1384  * the required bus ID may not be available.
1385  *
1386  * When this returns zero, the specified adapter became available for
1387  * clients using the bus number provided in adap->nr.  Also, the table
1388  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1389  * and the appropriate driver model device nodes are created.  Otherwise, a
1390  * negative errno value is returned.
1391  */
1392 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1393 {
1394         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1395                 return i2c_add_adapter(adap);
1396
1397         return __i2c_add_numbered_adapter(adap);
1398 }
1399 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1400
1401 static void i2c_do_del_adapter(struct i2c_driver *driver,
1402                               struct i2c_adapter *adapter)
1403 {
1404         struct i2c_client *client, *_n;
1405
1406         /* Remove the devices we created ourselves as the result of hardware
1407          * probing (using a driver's detect method) */
1408         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1409                 if (client->adapter == adapter) {
1410                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1411                                 client->name, client->addr);
1412                         list_del(&client->detected);
1413                         i2c_unregister_device(client);
1414                 }
1415         }
1416 }
1417
1418 static int __unregister_client(struct device *dev, void *dummy)
1419 {
1420         struct i2c_client *client = i2c_verify_client(dev);
1421         if (client && strcmp(client->name, "dummy"))
1422                 i2c_unregister_device(client);
1423         return 0;
1424 }
1425
1426 static int __unregister_dummy(struct device *dev, void *dummy)
1427 {
1428         struct i2c_client *client = i2c_verify_client(dev);
1429         i2c_unregister_device(client);
1430         return 0;
1431 }
1432
1433 static int __process_removed_adapter(struct device_driver *d, void *data)
1434 {
1435         i2c_do_del_adapter(to_i2c_driver(d), data);
1436         return 0;
1437 }
1438
1439 /**
1440  * i2c_del_adapter - unregister I2C adapter
1441  * @adap: the adapter being unregistered
1442  * Context: can sleep
1443  *
1444  * This unregisters an I2C adapter which was previously registered
1445  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1446  */
1447 void i2c_del_adapter(struct i2c_adapter *adap)
1448 {
1449         struct i2c_adapter *found;
1450         struct i2c_client *client, *next;
1451
1452         /* First make sure that this adapter was ever added */
1453         mutex_lock(&core_lock);
1454         found = idr_find(&i2c_adapter_idr, adap->nr);
1455         mutex_unlock(&core_lock);
1456         if (found != adap) {
1457                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1458                 return;
1459         }
1460
1461         i2c_acpi_remove_space_handler(adap);
1462         /* Tell drivers about this removal */
1463         mutex_lock(&core_lock);
1464         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1465                                __process_removed_adapter);
1466         mutex_unlock(&core_lock);
1467
1468         /* Remove devices instantiated from sysfs */
1469         mutex_lock_nested(&adap->userspace_clients_lock,
1470                           i2c_adapter_depth(adap));
1471         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1472                                  detected) {
1473                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1474                         client->addr);
1475                 list_del(&client->detected);
1476                 i2c_unregister_device(client);
1477         }
1478         mutex_unlock(&adap->userspace_clients_lock);
1479
1480         /* Detach any active clients. This can't fail, thus we do not
1481          * check the returned value. This is a two-pass process, because
1482          * we can't remove the dummy devices during the first pass: they
1483          * could have been instantiated by real devices wishing to clean
1484          * them up properly, so we give them a chance to do that first. */
1485         device_for_each_child(&adap->dev, NULL, __unregister_client);
1486         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1487
1488 #ifdef CONFIG_I2C_COMPAT
1489         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1490                                  adap->dev.parent);
1491 #endif
1492
1493         /* device name is gone after device_unregister */
1494         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1495
1496         pm_runtime_disable(&adap->dev);
1497
1498         i2c_host_notify_irq_teardown(adap);
1499
1500         /* wait until all references to the device are gone
1501          *
1502          * FIXME: This is old code and should ideally be replaced by an
1503          * alternative which results in decoupling the lifetime of the struct
1504          * device from the i2c_adapter, like spi or netdev do. Any solution
1505          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1506          */
1507         init_completion(&adap->dev_released);
1508         device_unregister(&adap->dev);
1509         wait_for_completion(&adap->dev_released);
1510
1511         /* free bus id */
1512         mutex_lock(&core_lock);
1513         idr_remove(&i2c_adapter_idr, adap->nr);
1514         mutex_unlock(&core_lock);
1515
1516         /* Clear the device structure in case this adapter is ever going to be
1517            added again */
1518         memset(&adap->dev, 0, sizeof(adap->dev));
1519 }
1520 EXPORT_SYMBOL(i2c_del_adapter);
1521
1522 /**
1523  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1524  * @dev: The device to scan for I2C timing properties
1525  * @t: the i2c_timings struct to be filled with values
1526  * @use_defaults: bool to use sane defaults derived from the I2C specification
1527  *                when properties are not found, otherwise use 0
1528  *
1529  * Scan the device for the generic I2C properties describing timing parameters
1530  * for the signal and fill the given struct with the results. If a property was
1531  * not found and use_defaults was true, then maximum timings are assumed which
1532  * are derived from the I2C specification. If use_defaults is not used, the
1533  * results will be 0, so drivers can apply their own defaults later. The latter
1534  * is mainly intended for avoiding regressions of existing drivers which want
1535  * to switch to this function. New drivers almost always should use the defaults.
1536  */
1537
1538 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1539 {
1540         int ret;
1541
1542         memset(t, 0, sizeof(*t));
1543
1544         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1545         if (ret && use_defaults)
1546                 t->bus_freq_hz = 100000;
1547
1548         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1549         if (ret && use_defaults) {
1550                 if (t->bus_freq_hz <= 100000)
1551                         t->scl_rise_ns = 1000;
1552                 else if (t->bus_freq_hz <= 400000)
1553                         t->scl_rise_ns = 300;
1554                 else
1555                         t->scl_rise_ns = 120;
1556         }
1557
1558         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1559         if (ret && use_defaults) {
1560                 if (t->bus_freq_hz <= 400000)
1561                         t->scl_fall_ns = 300;
1562                 else
1563                         t->scl_fall_ns = 120;
1564         }
1565
1566         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1567
1568         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1569         if (ret && use_defaults)
1570                 t->sda_fall_ns = t->scl_fall_ns;
1571
1572         device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1573 }
1574 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1575
1576 /* ------------------------------------------------------------------------- */
1577
1578 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1579 {
1580         int res;
1581
1582         mutex_lock(&core_lock);
1583         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1584         mutex_unlock(&core_lock);
1585
1586         return res;
1587 }
1588 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1589
1590 static int __process_new_driver(struct device *dev, void *data)
1591 {
1592         if (dev->type != &i2c_adapter_type)
1593                 return 0;
1594         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1595 }
1596
1597 /*
1598  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1599  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1600  */
1601
1602 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1603 {
1604         int res;
1605
1606         /* Can't register until after driver model init */
1607         if (WARN_ON(!is_registered))
1608                 return -EAGAIN;
1609
1610         /* add the driver to the list of i2c drivers in the driver core */
1611         driver->driver.owner = owner;
1612         driver->driver.bus = &i2c_bus_type;
1613         INIT_LIST_HEAD(&driver->clients);
1614
1615         /* When registration returns, the driver core
1616          * will have called probe() for all matching-but-unbound devices.
1617          */
1618         res = driver_register(&driver->driver);
1619         if (res)
1620                 return res;
1621
1622         pr_debug("driver [%s] registered\n", driver->driver.name);
1623
1624         /* Walk the adapters that are already present */
1625         i2c_for_each_dev(driver, __process_new_driver);
1626
1627         return 0;
1628 }
1629 EXPORT_SYMBOL(i2c_register_driver);
1630
1631 static int __process_removed_driver(struct device *dev, void *data)
1632 {
1633         if (dev->type == &i2c_adapter_type)
1634                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1635         return 0;
1636 }
1637
1638 /**
1639  * i2c_del_driver - unregister I2C driver
1640  * @driver: the driver being unregistered
1641  * Context: can sleep
1642  */
1643 void i2c_del_driver(struct i2c_driver *driver)
1644 {
1645         i2c_for_each_dev(driver, __process_removed_driver);
1646
1647         driver_unregister(&driver->driver);
1648         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1649 }
1650 EXPORT_SYMBOL(i2c_del_driver);
1651
1652 /* ------------------------------------------------------------------------- */
1653
1654 /**
1655  * i2c_use_client - increments the reference count of the i2c client structure
1656  * @client: the client being referenced
1657  *
1658  * Each live reference to a client should be refcounted. The driver model does
1659  * that automatically as part of driver binding, so that most drivers don't
1660  * need to do this explicitly: they hold a reference until they're unbound
1661  * from the device.
1662  *
1663  * A pointer to the client with the incremented reference counter is returned.
1664  */
1665 struct i2c_client *i2c_use_client(struct i2c_client *client)
1666 {
1667         if (client && get_device(&client->dev))
1668                 return client;
1669         return NULL;
1670 }
1671 EXPORT_SYMBOL(i2c_use_client);
1672
1673 /**
1674  * i2c_release_client - release a use of the i2c client structure
1675  * @client: the client being no longer referenced
1676  *
1677  * Must be called when a user of a client is finished with it.
1678  */
1679 void i2c_release_client(struct i2c_client *client)
1680 {
1681         if (client)
1682                 put_device(&client->dev);
1683 }
1684 EXPORT_SYMBOL(i2c_release_client);
1685
1686 struct i2c_cmd_arg {
1687         unsigned        cmd;
1688         void            *arg;
1689 };
1690
1691 static int i2c_cmd(struct device *dev, void *_arg)
1692 {
1693         struct i2c_client       *client = i2c_verify_client(dev);
1694         struct i2c_cmd_arg      *arg = _arg;
1695         struct i2c_driver       *driver;
1696
1697         if (!client || !client->dev.driver)
1698                 return 0;
1699
1700         driver = to_i2c_driver(client->dev.driver);
1701         if (driver->command)
1702                 driver->command(client, arg->cmd, arg->arg);
1703         return 0;
1704 }
1705
1706 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1707 {
1708         struct i2c_cmd_arg      cmd_arg;
1709
1710         cmd_arg.cmd = cmd;
1711         cmd_arg.arg = arg;
1712         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1713 }
1714 EXPORT_SYMBOL(i2c_clients_command);
1715
1716 static int __init i2c_init(void)
1717 {
1718         int retval;
1719
1720         retval = of_alias_get_highest_id("i2c");
1721
1722         down_write(&__i2c_board_lock);
1723         if (retval >= __i2c_first_dynamic_bus_num)
1724                 __i2c_first_dynamic_bus_num = retval + 1;
1725         up_write(&__i2c_board_lock);
1726
1727         retval = bus_register(&i2c_bus_type);
1728         if (retval)
1729                 return retval;
1730
1731         is_registered = true;
1732
1733 #ifdef CONFIG_I2C_COMPAT
1734         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1735         if (!i2c_adapter_compat_class) {
1736                 retval = -ENOMEM;
1737                 goto bus_err;
1738         }
1739 #endif
1740         retval = i2c_add_driver(&dummy_driver);
1741         if (retval)
1742                 goto class_err;
1743
1744         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1745                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1746         if (IS_ENABLED(CONFIG_ACPI))
1747                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1748
1749         return 0;
1750
1751 class_err:
1752 #ifdef CONFIG_I2C_COMPAT
1753         class_compat_unregister(i2c_adapter_compat_class);
1754 bus_err:
1755 #endif
1756         is_registered = false;
1757         bus_unregister(&i2c_bus_type);
1758         return retval;
1759 }
1760
1761 static void __exit i2c_exit(void)
1762 {
1763         if (IS_ENABLED(CONFIG_ACPI))
1764                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1765         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1766                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1767         i2c_del_driver(&dummy_driver);
1768 #ifdef CONFIG_I2C_COMPAT
1769         class_compat_unregister(i2c_adapter_compat_class);
1770 #endif
1771         bus_unregister(&i2c_bus_type);
1772         tracepoint_synchronize_unregister();
1773 }
1774
1775 /* We must initialize early, because some subsystems register i2c drivers
1776  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1777  */
1778 postcore_initcall(i2c_init);
1779 module_exit(i2c_exit);
1780
1781 /* ----------------------------------------------------
1782  * the functional interface to the i2c busses.
1783  * ----------------------------------------------------
1784  */
1785
1786 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1787 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1788
1789 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1790 {
1791         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1792                             err_msg, msg->addr, msg->len,
1793                             msg->flags & I2C_M_RD ? "read" : "write");
1794         return -EOPNOTSUPP;
1795 }
1796
1797 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1798 {
1799         const struct i2c_adapter_quirks *q = adap->quirks;
1800         int max_num = q->max_num_msgs, i;
1801         bool do_len_check = true;
1802
1803         if (q->flags & I2C_AQ_COMB) {
1804                 max_num = 2;
1805
1806                 /* special checks for combined messages */
1807                 if (num == 2) {
1808                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1809                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1810
1811                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1812                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1813
1814                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1815                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1816
1817                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1818                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1819
1820                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1821                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1822
1823                         do_len_check = false;
1824                 }
1825         }
1826
1827         if (i2c_quirk_exceeded(num, max_num))
1828                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1829
1830         for (i = 0; i < num; i++) {
1831                 u16 len = msgs[i].len;
1832
1833                 if (msgs[i].flags & I2C_M_RD) {
1834                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1835                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1836
1837                         if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1838                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1839                 } else {
1840                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1841                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1842
1843                         if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1844                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1845                 }
1846         }
1847
1848         return 0;
1849 }
1850
1851 /**
1852  * __i2c_transfer - unlocked flavor of i2c_transfer
1853  * @adap: Handle to I2C bus
1854  * @msgs: One or more messages to execute before STOP is issued to
1855  *      terminate the operation; each message begins with a START.
1856  * @num: Number of messages to be executed.
1857  *
1858  * Returns negative errno, else the number of messages executed.
1859  *
1860  * Adapter lock must be held when calling this function. No debug logging
1861  * takes place. adap->algo->master_xfer existence isn't checked.
1862  */
1863 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1864 {
1865         unsigned long orig_jiffies;
1866         int ret, try;
1867
1868         if (WARN_ON(!msgs || num < 1))
1869                 return -EINVAL;
1870         if (WARN_ON(test_bit(I2C_ALF_IS_SUSPENDED, &adap->locked_flags)))
1871                 return -ESHUTDOWN;
1872
1873         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1874                 return -EOPNOTSUPP;
1875
1876         /*
1877          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1878          * enabled.  This is an efficient way of keeping the for-loop from
1879          * being executed when not needed.
1880          */
1881         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1882                 int i;
1883                 for (i = 0; i < num; i++)
1884                         if (msgs[i].flags & I2C_M_RD)
1885                                 trace_i2c_read(adap, &msgs[i], i);
1886                         else
1887                                 trace_i2c_write(adap, &msgs[i], i);
1888         }
1889
1890         /* Retry automatically on arbitration loss */
1891         orig_jiffies = jiffies;
1892         for (ret = 0, try = 0; try <= adap->retries; try++) {
1893                 ret = adap->algo->master_xfer(adap, msgs, num);
1894                 if (ret != -EAGAIN)
1895                         break;
1896                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1897                         break;
1898         }
1899
1900         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1901                 int i;
1902                 for (i = 0; i < ret; i++)
1903                         if (msgs[i].flags & I2C_M_RD)
1904                                 trace_i2c_reply(adap, &msgs[i], i);
1905                 trace_i2c_result(adap, num, ret);
1906         }
1907
1908         return ret;
1909 }
1910 EXPORT_SYMBOL(__i2c_transfer);
1911
1912 /**
1913  * i2c_transfer - execute a single or combined I2C message
1914  * @adap: Handle to I2C bus
1915  * @msgs: One or more messages to execute before STOP is issued to
1916  *      terminate the operation; each message begins with a START.
1917  * @num: Number of messages to be executed.
1918  *
1919  * Returns negative errno, else the number of messages executed.
1920  *
1921  * Note that there is no requirement that each message be sent to
1922  * the same slave address, although that is the most common model.
1923  */
1924 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1925 {
1926         int ret;
1927
1928         if (!adap->algo->master_xfer) {
1929                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1930                 return -EOPNOTSUPP;
1931         }
1932
1933         /* REVISIT the fault reporting model here is weak:
1934          *
1935          *  - When we get an error after receiving N bytes from a slave,
1936          *    there is no way to report "N".
1937          *
1938          *  - When we get a NAK after transmitting N bytes to a slave,
1939          *    there is no way to report "N" ... or to let the master
1940          *    continue executing the rest of this combined message, if
1941          *    that's the appropriate response.
1942          *
1943          *  - When for example "num" is two and we successfully complete
1944          *    the first message but get an error part way through the
1945          *    second, it's unclear whether that should be reported as
1946          *    one (discarding status on the second message) or errno
1947          *    (discarding status on the first one).
1948          */
1949         if (in_atomic() || irqs_disabled()) {
1950                 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1951                 if (!ret)
1952                         /* I2C activity is ongoing. */
1953                         return -EAGAIN;
1954         } else {
1955                 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1956         }
1957
1958         ret = __i2c_transfer(adap, msgs, num);
1959         i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1960
1961         return ret;
1962 }
1963 EXPORT_SYMBOL(i2c_transfer);
1964
1965 /**
1966  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1967  *                             to/from a buffer
1968  * @client: Handle to slave device
1969  * @buf: Where the data is stored
1970  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1971  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1972  *
1973  * Returns negative errno, or else the number of bytes transferred.
1974  */
1975 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1976                               int count, u16 flags)
1977 {
1978         int ret;
1979         struct i2c_msg msg = {
1980                 .addr = client->addr,
1981                 .flags = flags | (client->flags & I2C_M_TEN),
1982                 .len = count,
1983                 .buf = buf,
1984         };
1985
1986         ret = i2c_transfer(client->adapter, &msg, 1);
1987
1988         /*
1989          * If everything went ok (i.e. 1 msg transferred), return #bytes
1990          * transferred, else error code.
1991          */
1992         return (ret == 1) ? count : ret;
1993 }
1994 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1995
1996 /**
1997  * i2c_get_device_id - get manufacturer, part id and die revision of a device
1998  * @client: The device to query
1999  * @id: The queried information
2000  *
2001  * Returns negative errno on error, zero on success.
2002  */
2003 int i2c_get_device_id(const struct i2c_client *client,
2004                       struct i2c_device_identity *id)
2005 {
2006         struct i2c_adapter *adap = client->adapter;
2007         union i2c_smbus_data raw_id;
2008         int ret;
2009
2010         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2011                 return -EOPNOTSUPP;
2012
2013         raw_id.block[0] = 3;
2014         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2015                              I2C_SMBUS_READ, client->addr << 1,
2016                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2017         if (ret)
2018                 return ret;
2019
2020         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2021         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2022         id->die_revision = raw_id.block[3] & 0x7;
2023         return 0;
2024 }
2025 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2026
2027 /* ----------------------------------------------------
2028  * the i2c address scanning function
2029  * Will not work for 10-bit addresses!
2030  * ----------------------------------------------------
2031  */
2032
2033 /*
2034  * Legacy default probe function, mostly relevant for SMBus. The default
2035  * probe method is a quick write, but it is known to corrupt the 24RF08
2036  * EEPROMs due to a state machine bug, and could also irreversibly
2037  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2038  * we use a short byte read instead. Also, some bus drivers don't implement
2039  * quick write, so we fallback to a byte read in that case too.
2040  * On x86, there is another special case for FSC hardware monitoring chips,
2041  * which want regular byte reads (address 0x73.) Fortunately, these are the
2042  * only known chips using this I2C address on PC hardware.
2043  * Returns 1 if probe succeeded, 0 if not.
2044  */
2045 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2046 {
2047         int err;
2048         union i2c_smbus_data dummy;
2049
2050 #ifdef CONFIG_X86
2051         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2052          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2053                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2054                                      I2C_SMBUS_BYTE_DATA, &dummy);
2055         else
2056 #endif
2057         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2058          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2059                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2060                                      I2C_SMBUS_QUICK, NULL);
2061         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2062                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2063                                      I2C_SMBUS_BYTE, &dummy);
2064         else {
2065                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2066                          addr);
2067                 err = -EOPNOTSUPP;
2068         }
2069
2070         return err >= 0;
2071 }
2072
2073 static int i2c_detect_address(struct i2c_client *temp_client,
2074                               struct i2c_driver *driver)
2075 {
2076         struct i2c_board_info info;
2077         struct i2c_adapter *adapter = temp_client->adapter;
2078         int addr = temp_client->addr;
2079         int err;
2080
2081         /* Make sure the address is valid */
2082         err = i2c_check_7bit_addr_validity_strict(addr);
2083         if (err) {
2084                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2085                          addr);
2086                 return err;
2087         }
2088
2089         /* Skip if already in use (7 bit, no need to encode flags) */
2090         if (i2c_check_addr_busy(adapter, addr))
2091                 return 0;
2092
2093         /* Make sure there is something at this address */
2094         if (!i2c_default_probe(adapter, addr))
2095                 return 0;
2096
2097         /* Finally call the custom detection function */
2098         memset(&info, 0, sizeof(struct i2c_board_info));
2099         info.addr = addr;
2100         err = driver->detect(temp_client, &info);
2101         if (err) {
2102                 /* -ENODEV is returned if the detection fails. We catch it
2103                    here as this isn't an error. */
2104                 return err == -ENODEV ? 0 : err;
2105         }
2106
2107         /* Consistency check */
2108         if (info.type[0] == '\0') {
2109                 dev_err(&adapter->dev,
2110                         "%s detection function provided no name for 0x%x\n",
2111                         driver->driver.name, addr);
2112         } else {
2113                 struct i2c_client *client;
2114
2115                 /* Detection succeeded, instantiate the device */
2116                 if (adapter->class & I2C_CLASS_DEPRECATED)
2117                         dev_warn(&adapter->dev,
2118                                 "This adapter will soon drop class based instantiation of devices. "
2119                                 "Please make sure client 0x%02x gets instantiated by other means. "
2120                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2121                                 info.addr);
2122
2123                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2124                         info.type, info.addr);
2125                 client = i2c_new_device(adapter, &info);
2126                 if (client)
2127                         list_add_tail(&client->detected, &driver->clients);
2128                 else
2129                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2130                                 info.type, info.addr);
2131         }
2132         return 0;
2133 }
2134
2135 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2136 {
2137         const unsigned short *address_list;
2138         struct i2c_client *temp_client;
2139         int i, err = 0;
2140         int adap_id = i2c_adapter_id(adapter);
2141
2142         address_list = driver->address_list;
2143         if (!driver->detect || !address_list)
2144                 return 0;
2145
2146         /* Warn that the adapter lost class based instantiation */
2147         if (adapter->class == I2C_CLASS_DEPRECATED) {
2148                 dev_dbg(&adapter->dev,
2149                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2150                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2151                         driver->driver.name);
2152                 return 0;
2153         }
2154
2155         /* Stop here if the classes do not match */
2156         if (!(adapter->class & driver->class))
2157                 return 0;
2158
2159         /* Set up a temporary client to help detect callback */
2160         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2161         if (!temp_client)
2162                 return -ENOMEM;
2163         temp_client->adapter = adapter;
2164
2165         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2166                 dev_dbg(&adapter->dev,
2167                         "found normal entry for adapter %d, addr 0x%02x\n",
2168                         adap_id, address_list[i]);
2169                 temp_client->addr = address_list[i];
2170                 err = i2c_detect_address(temp_client, driver);
2171                 if (unlikely(err))
2172                         break;
2173         }
2174
2175         kfree(temp_client);
2176         return err;
2177 }
2178
2179 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2180 {
2181         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2182                               I2C_SMBUS_QUICK, NULL) >= 0;
2183 }
2184 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2185
2186 struct i2c_client *
2187 i2c_new_probed_device(struct i2c_adapter *adap,
2188                       struct i2c_board_info *info,
2189                       unsigned short const *addr_list,
2190                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2191 {
2192         int i;
2193
2194         if (!probe)
2195                 probe = i2c_default_probe;
2196
2197         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2198                 /* Check address validity */
2199                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2200                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2201                                  addr_list[i]);
2202                         continue;
2203                 }
2204
2205                 /* Check address availability (7 bit, no need to encode flags) */
2206                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2207                         dev_dbg(&adap->dev,
2208                                 "Address 0x%02x already in use, not probing\n",
2209                                 addr_list[i]);
2210                         continue;
2211                 }
2212
2213                 /* Test address responsiveness */
2214                 if (probe(adap, addr_list[i]))
2215                         break;
2216         }
2217
2218         if (addr_list[i] == I2C_CLIENT_END) {
2219                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2220                 return NULL;
2221         }
2222
2223         info->addr = addr_list[i];
2224         return i2c_new_device(adap, info);
2225 }
2226 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2227
2228 struct i2c_adapter *i2c_get_adapter(int nr)
2229 {
2230         struct i2c_adapter *adapter;
2231
2232         mutex_lock(&core_lock);
2233         adapter = idr_find(&i2c_adapter_idr, nr);
2234         if (!adapter)
2235                 goto exit;
2236
2237         if (try_module_get(adapter->owner))
2238                 get_device(&adapter->dev);
2239         else
2240                 adapter = NULL;
2241
2242  exit:
2243         mutex_unlock(&core_lock);
2244         return adapter;
2245 }
2246 EXPORT_SYMBOL(i2c_get_adapter);
2247
2248 void i2c_put_adapter(struct i2c_adapter *adap)
2249 {
2250         if (!adap)
2251                 return;
2252
2253         put_device(&adap->dev);
2254         module_put(adap->owner);
2255 }
2256 EXPORT_SYMBOL(i2c_put_adapter);
2257
2258 /**
2259  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2260  * @msg: the message to be checked
2261  * @threshold: the minimum number of bytes for which using DMA makes sense
2262  *
2263  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2264  *         Or a valid pointer to be used with DMA. After use, release it by
2265  *         calling i2c_put_dma_safe_msg_buf().
2266  *
2267  * This function must only be called from process context!
2268  */
2269 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2270 {
2271         if (msg->len < threshold)
2272                 return NULL;
2273
2274         if (msg->flags & I2C_M_DMA_SAFE)
2275                 return msg->buf;
2276
2277         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2278                  msg->addr, msg->len);
2279
2280         if (msg->flags & I2C_M_RD)
2281                 return kzalloc(msg->len, GFP_KERNEL);
2282         else
2283                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2284 }
2285 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2286
2287 /**
2288  * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2289  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2290  * @msg: the message which the buffer corresponds to
2291  * @xferred: bool saying if the message was transferred
2292  */
2293 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2294 {
2295         if (!buf || buf == msg->buf)
2296                 return;
2297
2298         if (xferred && msg->flags & I2C_M_RD)
2299                 memcpy(msg->buf, buf, msg->len);
2300
2301         kfree(buf);
2302 }
2303 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2304
2305 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2306 MODULE_DESCRIPTION("I2C-Bus main module");
2307 MODULE_LICENSE("GPL");