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, and attach_adapter calls 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 /*
 162  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 163  * We will generate clock with rate 100 KHz and so duration of both clock levels
 164  * is: delay in ns = (10^6 / 100) / 2
 165  */
 166 #define RECOVERY_NDELAY         5000
 167 #define RECOVERY_CLK_CNT        9
 168
 169 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 170 {
 171         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 172         int i = 0, val = 1, ret = 0;
 173
 174         if (bri->prepare_recovery)
 175                 bri->prepare_recovery(adap);
 176
 177         bri->set_scl(adap, val);
 178         if (bri->set_sda)
 179                 bri->set_sda(adap, 1);
 180         ndelay(RECOVERY_NDELAY);
 181
 182         /*
 183          * By this time SCL is high, as we need to give 9 falling-rising edges
 184          */
 185         while (i++ < RECOVERY_CLK_CNT * 2) {
 186                 if (val) {
 187                         /* SCL shouldn't be low here */
 188                         if (!bri->get_scl(adap)) {
 189                                 dev_err(&adap->dev,
 190                                         "SCL is stuck low, exit recovery\n");
 191                                 ret = -EBUSY;
 192                                 break;
 193                         }
 194                         /* Break if SDA is high */
 195                         if (bri->get_sda && bri->get_sda(adap))
 196                                 break;
 197                 }
 198
 199                 val = !val;
 200                 bri->set_scl(adap, val);
 201
 202                 /*
 203                  * If we can set SDA, we will always create STOP here to ensure
 204                  * the additional pulses will do no harm. This is achieved by
 205                  * letting SDA follow SCL half a cycle later.
 206                  */
 207                 ndelay(RECOVERY_NDELAY / 2);
 208                 if (bri->set_sda)
 209                         bri->set_sda(adap, val);
 210                 ndelay(RECOVERY_NDELAY / 2);
 211         }
 212
 213         /* check if recovery actually succeeded */
 214         if (bri->get_sda && !bri->get_sda(adap))
 215                 ret = -EBUSY;
 216
 217         /* If all went well, send STOP for a sane bus state. */
 218         if (ret == 0 && bri->set_sda) {
 219                 bri->set_scl(adap, 0);
 220                 ndelay(RECOVERY_NDELAY / 2);
 221                 bri->set_sda(adap, 0);
 222                 ndelay(RECOVERY_NDELAY / 2);
 223                 bri->set_scl(adap, 1);
 224                 ndelay(RECOVERY_NDELAY / 2);
 225                 bri->set_sda(adap, 1);
 226                 ndelay(RECOVERY_NDELAY / 2);
 227         }
 228
 229         if (bri->unprepare_recovery)
 230                 bri->unprepare_recovery(adap);
 231
 232         return ret;
 233 }
 234 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 235
 236 int i2c_recover_bus(struct i2c_adapter *adap)
 237 {
 238         if (!adap->bus_recovery_info)
 239                 return -EOPNOTSUPP;
 240
 241         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 242         return adap->bus_recovery_info->recover_bus(adap);
 243 }
 244 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 245
 246 static void i2c_init_recovery(struct i2c_adapter *adap)
 247 {
 248         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 249         char *err_str;
 250
 251         if (!bri)
 252                 return;
 253
 254         if (!bri->recover_bus) {
 255                 err_str = "no recover_bus() found";
 256                 goto err;
 257         }
 258
 259         if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 260                 bri->get_scl = get_scl_gpio_value;
 261                 bri->set_scl = set_scl_gpio_value;
 262                 if (bri->sda_gpiod) {
 263                         bri->get_sda = get_sda_gpio_value;
 264                         /* FIXME: add proper flag instead of '0' once available */
 265                         if (gpiod_get_direction(bri->sda_gpiod) == 0)
 266                                 bri->set_sda = set_sda_gpio_value;
 267                 }
 268                 return;
 269         }
 270
 271         if (bri->recover_bus == i2c_generic_scl_recovery) {
 272                 /* Generic SCL recovery */
 273                 if (!bri->set_scl || !bri->get_scl) {
 274                         err_str = "no {get|set}_scl() found";
 275                         goto err;
 276                 }
 277         }
 278
 279         return;
 280  err:
 281         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 282         adap->bus_recovery_info = NULL;
 283 }
 284
 285 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 286 {
 287         struct i2c_adapter *adap = client->adapter;
 288         unsigned int irq;
 289
 290         if (!adap->host_notify_domain)
 291                 return -ENXIO;
 292
 293         if (client->flags & I2C_CLIENT_TEN)
 294                 return -EINVAL;
 295
 296         irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 297         if (!irq)
 298                 irq = irq_create_mapping(adap->host_notify_domain,
 299                                          client->addr);
 300
 301         return irq > 0 ? irq : -ENXIO;
 302 }
 303
 304 static int i2c_device_probe(struct device *dev)
 305 {
 306         struct i2c_client       *client = i2c_verify_client(dev);
 307         struct i2c_driver       *driver;
 308         int status;
 309
 310         if (!client)
 311                 return 0;
 312
 313         driver = to_i2c_driver(dev->driver);
 314
 315         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 316                 int irq = -ENOENT;
 317
 318                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 319                         dev_dbg(dev, "Using Host Notify IRQ\n");
 320                         irq = i2c_smbus_host_notify_to_irq(client);
 321                 } else if (dev->of_node) {
 322                         irq = of_irq_get_byname(dev->of_node, "irq");
 323                         if (irq == -EINVAL || irq == -ENODATA)
 324                                 irq = of_irq_get(dev->of_node, 0);
 325                 } else if (ACPI_COMPANION(dev)) {
 326                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 327                 }
 328                 if (irq == -EPROBE_DEFER)
 329                         return irq;
 330
 331                 if (irq < 0)
 332                         irq = 0;
 333
 334                 client->irq = irq;
 335         }
 336
 337         /*
 338          * An I2C ID table is not mandatory, if and only if, a suitable OF
 339          * or ACPI ID table is supplied for the probing device.
 340          */
 341         if (!driver->id_table &&
 342             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 343             !i2c_of_match_device(dev->driver->of_match_table, client))
 344                 return -ENODEV;
 345
 346         if (client->flags & I2C_CLIENT_WAKE) {
 347                 int wakeirq = -ENOENT;
 348
 349                 if (dev->of_node) {
 350                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 351                         if (wakeirq == -EPROBE_DEFER)
 352                                 return wakeirq;
 353                 }
 354
 355                 device_init_wakeup(&client->dev, true);
 356
 357                 if (wakeirq > 0 && wakeirq != client->irq)
 358                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 359                 else if (client->irq > 0)
 360                         status = dev_pm_set_wake_irq(dev, client->irq);
 361                 else
 362                         status = 0;
 363
 364                 if (status)
 365                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 366         }
 367
 368         dev_dbg(dev, "probe\n");
 369
 370         status = of_clk_set_defaults(dev->of_node, false);
 371         if (status < 0)
 372                 goto err_clear_wakeup_irq;
 373
 374         status = dev_pm_domain_attach(&client->dev, true);
 375         if (status)
 376                 goto err_clear_wakeup_irq;
 377
 378         /*
 379          * When there are no more users of probe(),
 380          * rename probe_new to probe.
 381          */
 382         if (driver->probe_new)
 383                 status = driver->probe_new(client);
 384         else if (driver->probe)
 385                 status = driver->probe(client,
 386                                        i2c_match_id(driver->id_table, client));
 387         else
 388                 status = -EINVAL;
 389
 390         if (status)
 391                 goto err_detach_pm_domain;
 392
 393         return 0;
 394
 395 err_detach_pm_domain:
 396         dev_pm_domain_detach(&client->dev, true);
 397 err_clear_wakeup_irq:
 398         dev_pm_clear_wake_irq(&client->dev);
 399         device_init_wakeup(&client->dev, false);
 400         return status;
 401 }
 402
 403 static int i2c_device_remove(struct device *dev)
 404 {
 405         struct i2c_client       *client = i2c_verify_client(dev);
 406         struct i2c_driver       *driver;
 407         int status = 0;
 408
 409         if (!client || !dev->driver)
 410                 return 0;
 411
 412         driver = to_i2c_driver(dev->driver);
 413         if (driver->remove) {
 414                 dev_dbg(dev, "remove\n");
 415                 status = driver->remove(client);
 416         }
 417
 418         dev_pm_domain_detach(&client->dev, true);
 419
 420         dev_pm_clear_wake_irq(&client->dev);
 421         device_init_wakeup(&client->dev, false);
 422
 423         return status;
 424 }
 425
 426 static void i2c_device_shutdown(struct device *dev)
 427 {
 428         struct i2c_client *client = i2c_verify_client(dev);
 429         struct i2c_driver *driver;
 430
 431         if (!client || !dev->driver)
 432                 return;
 433         driver = to_i2c_driver(dev->driver);
 434         if (driver->shutdown)
 435                 driver->shutdown(client);
 436 }
 437
 438 static void i2c_client_dev_release(struct device *dev)
 439 {
 440         kfree(to_i2c_client(dev));
 441 }
 442
 443 static ssize_t
 444 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 445 {
 446         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 447                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 448 }
 449 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 450
 451 static ssize_t
 452 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 453 {
 454         struct i2c_client *client = to_i2c_client(dev);
 455         int len;
 456
 457         len = of_device_modalias(dev, buf, PAGE_SIZE);
 458         if (len != -ENODEV)
 459                 return len;
 460
 461         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 462         if (len != -ENODEV)
 463                 return len;
 464
 465         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 466 }
 467 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 468
 469 static struct attribute *i2c_dev_attrs[] = {
 470         &dev_attr_name.attr,
 471         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 472         &dev_attr_modalias.attr,
 473         NULL
 474 };
 475 ATTRIBUTE_GROUPS(i2c_dev);
 476
 477 struct bus_type i2c_bus_type = {
 478         .name           = "i2c",
 479         .match          = i2c_device_match,
 480         .probe          = i2c_device_probe,
 481         .remove         = i2c_device_remove,
 482         .shutdown       = i2c_device_shutdown,
 483 };
 484 EXPORT_SYMBOL_GPL(i2c_bus_type);
 485
 486 struct device_type i2c_client_type = {
 487         .groups         = i2c_dev_groups,
 488         .uevent         = i2c_device_uevent,
 489         .release        = i2c_client_dev_release,
 490 };
 491 EXPORT_SYMBOL_GPL(i2c_client_type);
 492
 493
 494 /**
 495  * i2c_verify_client - return parameter as i2c_client, or NULL
 496  * @dev: device, probably from some driver model iterator
 497  *
 498  * When traversing the driver model tree, perhaps using driver model
 499  * iterators like @device_for_each_child(), you can't assume very much
 500  * about the nodes you find.  Use this function to avoid oopses caused
 501  * by wrongly treating some non-I2C device as an i2c_client.
 502  */
 503 struct i2c_client *i2c_verify_client(struct device *dev)
 504 {
 505         return (dev->type == &i2c_client_type)
 506                         ? to_i2c_client(dev)
 507                         : NULL;
 508 }
 509 EXPORT_SYMBOL(i2c_verify_client);
 510
 511
 512 /* Return a unique address which takes the flags of the client into account */
 513 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 514 {
 515         unsigned short addr = client->addr;
 516
 517         /* For some client flags, add an arbitrary offset to avoid collisions */
 518         if (client->flags & I2C_CLIENT_TEN)
 519                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 520
 521         if (client->flags & I2C_CLIENT_SLAVE)
 522                 addr |= I2C_ADDR_OFFSET_SLAVE;
 523
 524         return addr;
 525 }
 526
 527 /* This is a permissive address validity check, I2C address map constraints
 528  * are purposely not enforced, except for the general call address. */
 529 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 530 {
 531         if (flags & I2C_CLIENT_TEN) {
 532                 /* 10-bit address, all values are valid */
 533                 if (addr > 0x3ff)
 534                         return -EINVAL;
 535         } else {
 536                 /* 7-bit address, reject the general call address */
 537                 if (addr == 0x00 || addr > 0x7f)
 538                         return -EINVAL;
 539         }
 540         return 0;
 541 }
 542
 543 /* And this is a strict address validity check, used when probing. If a
 544  * device uses a reserved address, then it shouldn't be probed. 7-bit
 545  * addressing is assumed, 10-bit address devices are rare and should be
 546  * explicitly enumerated. */
 547 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 548 {
 549         /*
 550          * Reserved addresses per I2C specification:
 551          *  0x00       General call address / START byte
 552          *  0x01       CBUS address
 553          *  0x02       Reserved for different bus format
 554          *  0x03       Reserved for future purposes
 555          *  0x04-0x07  Hs-mode master code
 556          *  0x78-0x7b  10-bit slave addressing
 557          *  0x7c-0x7f  Reserved for future purposes
 558          */
 559         if (addr < 0x08 || addr > 0x77)
 560                 return -EINVAL;
 561         return 0;
 562 }
 563
 564 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 565 {
 566         struct i2c_client       *client = i2c_verify_client(dev);
 567         int                     addr = *(int *)addrp;
 568
 569         if (client && i2c_encode_flags_to_addr(client) == addr)
 570                 return -EBUSY;
 571         return 0;
 572 }
 573
 574 /* walk up mux tree */
 575 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 576 {
 577         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 578         int result;
 579
 580         result = device_for_each_child(&adapter->dev, &addr,
 581                                         __i2c_check_addr_busy);
 582
 583         if (!result && parent)
 584                 result = i2c_check_mux_parents(parent, addr);
 585
 586         return result;
 587 }
 588
 589 /* recurse down mux tree */
 590 static int i2c_check_mux_children(struct device *dev, void *addrp)
 591 {
 592         int result;
 593
 594         if (dev->type == &i2c_adapter_type)
 595                 result = device_for_each_child(dev, addrp,
 596                                                 i2c_check_mux_children);
 597         else
 598                 result = __i2c_check_addr_busy(dev, addrp);
 599
 600         return result;
 601 }
 602
 603 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 604 {
 605         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 606         int result = 0;
 607
 608         if (parent)
 609                 result = i2c_check_mux_parents(parent, addr);
 610
 611         if (!result)
 612                 result = device_for_each_child(&adapter->dev, &addr,
 613                                                 i2c_check_mux_children);
 614
 615         return result;
 616 }
 617
 618 /**
 619  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 620  * @adapter: Target I2C bus segment
 621  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 622  *      locks only this branch in the adapter tree
 623  */
 624 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 625                                  unsigned int flags)
 626 {
 627         rt_mutex_lock(&adapter->bus_lock);
 628 }
 629
 630 /**
 631  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 632  * @adapter: Target I2C bus segment
 633  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 634  *      trylocks only this branch in the adapter tree
 635  */
 636 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 637                                    unsigned int flags)
 638 {
 639         return rt_mutex_trylock(&adapter->bus_lock);
 640 }
 641
 642 /**
 643  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 644  * @adapter: Target I2C bus segment
 645  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 646  *      unlocks only this branch in the adapter tree
 647  */
 648 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 649                                    unsigned int flags)
 650 {
 651         rt_mutex_unlock(&adapter->bus_lock);
 652 }
 653
 654 static void i2c_dev_set_name(struct i2c_adapter *adap,
 655                              struct i2c_client *client,
 656                              struct i2c_board_info const *info)
 657 {
 658         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 659
 660         if (info && info->dev_name) {
 661                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 662                 return;
 663         }
 664
 665         if (adev) {
 666                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 667                 return;
 668         }
 669
 670         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 671                      i2c_encode_flags_to_addr(client));
 672 }
 673
 674 static int i2c_dev_irq_from_resources(const struct resource *resources,
 675                                       unsigned int num_resources)
 676 {
 677         struct irq_data *irqd;
 678         int i;
 679
 680         for (i = 0; i < num_resources; i++) {
 681                 const struct resource *r = &resources[i];
 682
 683                 if (resource_type(r) != IORESOURCE_IRQ)
 684                         continue;
 685
 686                 if (r->flags & IORESOURCE_BITS) {
 687                         irqd = irq_get_irq_data(r->start);
 688                         if (!irqd)
 689                                 break;
 690
 691                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 692                 }
 693
 694                 return r->start;
 695         }
 696
 697         return 0;
 698 }
 699
 700 /**
 701  * i2c_new_device - instantiate an i2c device
 702  * @adap: the adapter managing the device
 703  * @info: describes one I2C device; bus_num is ignored
 704  * Context: can sleep
 705  *
 706  * Create an i2c device. Binding is handled through driver model
 707  * probe()/remove() methods.  A driver may be bound to this device when we
 708  * return from this function, or any later moment (e.g. maybe hotplugging will
 709  * load the driver module).  This call is not appropriate for use by mainboard
 710  * initialization logic, which usually runs during an arch_initcall() long
 711  * before any i2c_adapter could exist.
 712  *
 713  * This returns the new i2c client, which may be saved for later use with
 714  * i2c_unregister_device(); or NULL to indicate an error.
 715  */
 716 struct i2c_client *
 717 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 718 {
 719         struct i2c_client       *client;
 720         int                     status;
 721
 722         client = kzalloc(sizeof *client, GFP_KERNEL);
 723         if (!client)
 724                 return NULL;
 725
 726         client->adapter = adap;
 727
 728         client->dev.platform_data = info->platform_data;
 729         client->flags = info->flags;
 730         client->addr = info->addr;
 731
 732         client->irq = info->irq;
 733         if (!client->irq)
 734                 client->irq = i2c_dev_irq_from_resources(info->resources,
 735                                                          info->num_resources);
 736
 737         strlcpy(client->name, info->type, sizeof(client->name));
 738
 739         status = i2c_check_addr_validity(client->addr, client->flags);
 740         if (status) {
 741                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 742                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 743                 goto out_err_silent;
 744         }
 745
 746         /* Check for address business */
 747         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 748         if (status)
 749                 goto out_err;
 750
 751         client->dev.parent = &client->adapter->dev;
 752         client->dev.bus = &i2c_bus_type;
 753         client->dev.type = &i2c_client_type;
 754         client->dev.of_node = of_node_get(info->of_node);
 755         client->dev.fwnode = info->fwnode;
 756
 757         i2c_dev_set_name(adap, client, info);
 758
 759         if (info->properties) {
 760                 status = device_add_properties(&client->dev, info->properties);
 761                 if (status) {
 762                         dev_err(&adap->dev,
 763                                 "Failed to add properties to client %s: %d\n",
 764                                 client->name, status);
 765                         goto out_err_put_of_node;
 766                 }
 767         }
 768
 769         status = device_register(&client->dev);
 770         if (status)
 771                 goto out_free_props;
 772
 773         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 774                 client->name, dev_name(&client->dev));
 775
 776         return client;
 777
 778 out_free_props:
 779         if (info->properties)
 780                 device_remove_properties(&client->dev);
 781 out_err_put_of_node:
 782         of_node_put(info->of_node);
 783 out_err:
 784         dev_err(&adap->dev,
 785                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 786                 client->name, client->addr, status);
 787 out_err_silent:
 788         kfree(client);
 789         return NULL;
 790 }
 791 EXPORT_SYMBOL_GPL(i2c_new_device);
 792
 793
 794 /**
 795  * i2c_unregister_device - reverse effect of i2c_new_device()
 796  * @client: value returned from i2c_new_device()
 797  * Context: can sleep
 798  */
 799 void i2c_unregister_device(struct i2c_client *client)
 800 {
 801         if (!client)
 802                 return;
 803
 804         if (client->dev.of_node) {
 805                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 806                 of_node_put(client->dev.of_node);
 807         }
 808
 809         if (ACPI_COMPANION(&client->dev))
 810                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 811         device_unregister(&client->dev);
 812 }
 813 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 814
 815
 816 static const struct i2c_device_id dummy_id[] = {
 817         { "dummy", 0 },
 818         { },
 819 };
 820
 821 static int dummy_probe(struct i2c_client *client,
 822                        const struct i2c_device_id *id)
 823 {
 824         return 0;
 825 }
 826
 827 static int dummy_remove(struct i2c_client *client)
 828 {
 829         return 0;
 830 }
 831
 832 static struct i2c_driver dummy_driver = {
 833         .driver.name    = "dummy",
 834         .probe          = dummy_probe,
 835         .remove         = dummy_remove,
 836         .id_table       = dummy_id,
 837 };
 838
 839 /**
 840  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 841  * @adapter: the adapter managing the device
 842  * @address: seven bit address to be used
 843  * Context: can sleep
 844  *
 845  * This returns an I2C client bound to the "dummy" driver, intended for use
 846  * with devices that consume multiple addresses.  Examples of such chips
 847  * include various EEPROMS (like 24c04 and 24c08 models).
 848  *
 849  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 850  * except i2c_transfer() need a client handle; the dummy will be that handle.
 851  * And second, this prevents the specified address from being bound to a
 852  * different driver.
 853  *
 854  * This returns the new i2c client, which should be saved for later use with
 855  * i2c_unregister_device(); or NULL to indicate an error.
 856  */
 857 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 858 {
 859         struct i2c_board_info info = {
 860                 I2C_BOARD_INFO("dummy", address),
 861         };
 862
 863         return i2c_new_device(adapter, &info);
 864 }
 865 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 866
 867 /**
 868  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 869  * and create the associated device
 870  * @client: Handle to the primary client
 871  * @name: Handle to specify which secondary address to get
 872  * @default_addr: Used as a fallback if no secondary address was specified
 873  * Context: can sleep
 874  *
 875  * I2C clients can be composed of multiple I2C slaves bound together in a single
 876  * component. The I2C client driver then binds to the master I2C slave and needs
 877  * to create I2C dummy clients to communicate with all the other slaves.
 878  *
 879  * This function creates and returns an I2C dummy client whose I2C address is
 880  * retrieved from the platform firmware based on the given slave name. If no
 881  * address is specified by the firmware default_addr is used.
 882  *
 883  * On DT-based platforms the address is retrieved from the "reg" property entry
 884  * cell whose "reg-names" value matches the slave name.
 885  *
 886  * This returns the new i2c client, which should be saved for later use with
 887  * i2c_unregister_device(); or NULL to indicate an error.
 888  */
 889 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 890                                                 const char *name,
 891                                                 u16 default_addr)
 892 {
 893         struct device_node *np = client->dev.of_node;
 894         u32 addr = default_addr;
 895         int i;
 896
 897         if (np) {
 898                 i = of_property_match_string(np, "reg-names", name);
 899                 if (i >= 0)
 900                         of_property_read_u32_index(np, "reg", i, &addr);
 901         }
 902
 903         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 904         return i2c_new_dummy(client->adapter, addr);
 905 }
 906 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 907
 908 /* ------------------------------------------------------------------------- */
 909
 910 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 911
 912 static void i2c_adapter_dev_release(struct device *dev)
 913 {
 914         struct i2c_adapter *adap = to_i2c_adapter(dev);
 915         complete(&adap->dev_released);
 916 }
 917
 918 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 919 {
 920         unsigned int depth = 0;
 921
 922         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 923                 depth++;
 924
 925         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 926                   "adapter depth exceeds lockdep subclass limit\n");
 927
 928         return depth;
 929 }
 930 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 931
 932 /*
 933  * Let users instantiate I2C devices through sysfs. This can be used when
 934  * platform initialization code doesn't contain the proper data for
 935  * whatever reason. Also useful for drivers that do device detection and
 936  * detection fails, either because the device uses an unexpected address,
 937  * or this is a compatible device with different ID register values.
 938  *
 939  * Parameter checking may look overzealous, but we really don't want
 940  * the user to provide incorrect parameters.
 941  */
 942 static ssize_t
 943 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 944                      const char *buf, size_t count)
 945 {
 946         struct i2c_adapter *adap = to_i2c_adapter(dev);
 947         struct i2c_board_info info;
 948         struct i2c_client *client;
 949         char *blank, end;
 950         int res;
 951
 952         memset(&info, 0, sizeof(struct i2c_board_info));
 953
 954         blank = strchr(buf, ' ');
 955         if (!blank) {
 956                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 957                 return -EINVAL;
 958         }
 959         if (blank - buf > I2C_NAME_SIZE - 1) {
 960                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 961                 return -EINVAL;
 962         }
 963         memcpy(info.type, buf, blank - buf);
 964
 965         /* Parse remaining parameters, reject extra parameters */
 966         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 967         if (res < 1) {
 968                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 969                 return -EINVAL;
 970         }
 971         if (res > 1  && end != '\n') {
 972                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 973                 return -EINVAL;
 974         }
 975
 976         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 977                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 978                 info.flags |= I2C_CLIENT_TEN;
 979         }
 980
 981         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 982                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 983                 info.flags |= I2C_CLIENT_SLAVE;
 984         }
 985
 986         client = i2c_new_device(adap, &info);
 987         if (!client)
 988                 return -EINVAL;
 989
 990         /* Keep track of the added device */
 991         mutex_lock(&adap->userspace_clients_lock);
 992         list_add_tail(&client->detected, &adap->userspace_clients);
 993         mutex_unlock(&adap->userspace_clients_lock);
 994         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 995                  info.type, info.addr);
 996
 997         return count;
 998 }
 999 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1000
1001 /*
1002  * And of course let the users delete the devices they instantiated, if
1003  * they got it wrong. This interface can only be used to delete devices
1004  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1005  * don't delete devices to which some kernel code still has references.
1006  *
1007  * Parameter checking may look overzealous, but we really don't want
1008  * the user to delete the wrong device.
1009  */
1010 static ssize_t
1011 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1012                         const char *buf, size_t count)
1013 {
1014         struct i2c_adapter *adap = to_i2c_adapter(dev);
1015         struct i2c_client *client, *next;
1016         unsigned short addr;
1017         char end;
1018         int res;
1019
1020         /* Parse parameters, reject extra parameters */
1021         res = sscanf(buf, "%hi%c", &addr, &end);
1022         if (res < 1) {
1023                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1024                 return -EINVAL;
1025         }
1026         if (res > 1  && end != '\n') {
1027                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1028                 return -EINVAL;
1029         }
1030
1031         /* Make sure the device was added through sysfs */
1032         res = -ENOENT;
1033         mutex_lock_nested(&adap->userspace_clients_lock,
1034                           i2c_adapter_depth(adap));
1035         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1036                                  detected) {
1037                 if (i2c_encode_flags_to_addr(client) == addr) {
1038                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1039                                  "delete_device", client->name, client->addr);
1040
1041                         list_del(&client->detected);
1042                         i2c_unregister_device(client);
1043                         res = count;
1044                         break;
1045                 }
1046         }
1047         mutex_unlock(&adap->userspace_clients_lock);
1048
1049         if (res < 0)
1050                 dev_err(dev, "%s: Can't find device in list\n",
1051                         "delete_device");
1052         return res;
1053 }
1054 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1055                                    i2c_sysfs_delete_device);
1056
1057 static struct attribute *i2c_adapter_attrs[] = {
1058         &dev_attr_name.attr,
1059         &dev_attr_new_device.attr,
1060         &dev_attr_delete_device.attr,
1061         NULL
1062 };
1063 ATTRIBUTE_GROUPS(i2c_adapter);
1064
1065 struct device_type i2c_adapter_type = {
1066         .groups         = i2c_adapter_groups,
1067         .release        = i2c_adapter_dev_release,
1068 };
1069 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1070
1071 /**
1072  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1073  * @dev: device, probably from some driver model iterator
1074  *
1075  * When traversing the driver model tree, perhaps using driver model
1076  * iterators like @device_for_each_child(), you can't assume very much
1077  * about the nodes you find.  Use this function to avoid oopses caused
1078  * by wrongly treating some non-I2C device as an i2c_adapter.
1079  */
1080 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1081 {
1082         return (dev->type == &i2c_adapter_type)
1083                         ? to_i2c_adapter(dev)
1084                         : NULL;
1085 }
1086 EXPORT_SYMBOL(i2c_verify_adapter);
1087
1088 #ifdef CONFIG_I2C_COMPAT
1089 static struct class_compat *i2c_adapter_compat_class;
1090 #endif
1091
1092 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1093 {
1094         struct i2c_devinfo      *devinfo;
1095
1096         down_read(&__i2c_board_lock);
1097         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1098                 if (devinfo->busnum == adapter->nr
1099                                 && !i2c_new_device(adapter,
1100                                                 &devinfo->board_info))
1101                         dev_err(&adapter->dev,
1102                                 "Can't create device at 0x%02x\n",
1103                                 devinfo->board_info.addr);
1104         }
1105         up_read(&__i2c_board_lock);
1106 }
1107
1108 static int i2c_do_add_adapter(struct i2c_driver *driver,
1109                               struct i2c_adapter *adap)
1110 {
1111         /* Detect supported devices on that bus, and instantiate them */
1112         i2c_detect(adap, driver);
1113
1114         /* Let legacy drivers scan this bus for matching devices */
1115         if (driver->attach_adapter) {
1116                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1117                          driver->driver.name);
1118                 dev_warn(&adap->dev,
1119                          "Please use another way to instantiate your i2c_client\n");
1120                 /* We ignore the return code; if it fails, too bad */
1121                 driver->attach_adapter(adap);
1122         }
1123         return 0;
1124 }
1125
1126 static int __process_new_adapter(struct device_driver *d, void *data)
1127 {
1128         return i2c_do_add_adapter(to_i2c_driver(d), data);
1129 }
1130
1131 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1132         .lock_bus =    i2c_adapter_lock_bus,
1133         .trylock_bus = i2c_adapter_trylock_bus,
1134         .unlock_bus =  i2c_adapter_unlock_bus,
1135 };
1136
1137 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1138 {
1139         struct irq_domain *domain = adap->host_notify_domain;
1140         irq_hw_number_t hwirq;
1141
1142         if (!domain)
1143                 return;
1144
1145         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1146                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1147
1148         irq_domain_remove(domain);
1149         adap->host_notify_domain = NULL;
1150 }
1151
1152 static int i2c_host_notify_irq_map(struct irq_domain *h,
1153                                           unsigned int virq,
1154                                           irq_hw_number_t hw_irq_num)
1155 {
1156         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1157
1158         return 0;
1159 }
1160
1161 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1162         .map = i2c_host_notify_irq_map,
1163 };
1164
1165 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1166 {
1167         struct irq_domain *domain;
1168
1169         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1170                 return 0;
1171
1172         domain = irq_domain_create_linear(adap->dev.fwnode,
1173                                           I2C_ADDR_7BITS_COUNT,
1174                                           &i2c_host_notify_irq_ops, adap);
1175         if (!domain)
1176                 return -ENOMEM;
1177
1178         adap->host_notify_domain = domain;
1179
1180         return 0;
1181 }
1182
1183 /**
1184  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1185  * I2C client.
1186  * @adap: the adapter
1187  * @addr: the I2C address of the notifying device
1188  * Context: can't sleep
1189  *
1190  * Helper function to be called from an I2C bus driver's interrupt
1191  * handler. It will schedule the Host Notify IRQ.
1192  */
1193 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1194 {
1195         int irq;
1196
1197         if (!adap)
1198                 return -EINVAL;
1199
1200         irq = irq_find_mapping(adap->host_notify_domain, addr);
1201         if (irq <= 0)
1202                 return -ENXIO;
1203
1204         generic_handle_irq(irq);
1205
1206         return 0;
1207 }
1208 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1209
1210 static int i2c_register_adapter(struct i2c_adapter *adap)
1211 {
1212         int res = -EINVAL;
1213
1214         /* Can't register until after driver model init */
1215         if (WARN_ON(!is_registered)) {
1216                 res = -EAGAIN;
1217                 goto out_list;
1218         }
1219
1220         /* Sanity checks */
1221         if (WARN(!adap->name[0], "i2c adapter has no name"))
1222                 goto out_list;
1223
1224         if (!adap->algo) {
1225                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1226                 goto out_list;
1227         }
1228
1229         if (!adap->lock_ops)
1230                 adap->lock_ops = &i2c_adapter_lock_ops;
1231
1232         rt_mutex_init(&adap->bus_lock);
1233         rt_mutex_init(&adap->mux_lock);
1234         mutex_init(&adap->userspace_clients_lock);
1235         INIT_LIST_HEAD(&adap->userspace_clients);
1236
1237         /* Set default timeout to 1 second if not already set */
1238         if (adap->timeout == 0)
1239                 adap->timeout = HZ;
1240
1241         /* register soft irqs for Host Notify */
1242         res = i2c_setup_host_notify_irq_domain(adap);
1243         if (res) {
1244                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1245                        adap->name, res);
1246                 goto out_list;
1247         }
1248
1249         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1250         adap->dev.bus = &i2c_bus_type;
1251         adap->dev.type = &i2c_adapter_type;
1252         res = device_register(&adap->dev);
1253         if (res) {
1254                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1255                 goto out_list;
1256         }
1257
1258         res = of_i2c_setup_smbus_alert(adap);
1259         if (res)
1260                 goto out_reg;
1261
1262         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1263
1264         pm_runtime_no_callbacks(&adap->dev);
1265         pm_suspend_ignore_children(&adap->dev, true);
1266         pm_runtime_enable(&adap->dev);
1267
1268 #ifdef CONFIG_I2C_COMPAT
1269         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1270                                        adap->dev.parent);
1271         if (res)
1272                 dev_warn(&adap->dev,
1273                          "Failed to create compatibility class link\n");
1274 #endif
1275
1276         i2c_init_recovery(adap);
1277
1278         /* create pre-declared device nodes */
1279         of_i2c_register_devices(adap);
1280         i2c_acpi_register_devices(adap);
1281         i2c_acpi_install_space_handler(adap);
1282
1283         if (adap->nr < __i2c_first_dynamic_bus_num)
1284                 i2c_scan_static_board_info(adap);
1285
1286         /* Notify drivers */
1287         mutex_lock(&core_lock);
1288         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1289         mutex_unlock(&core_lock);
1290
1291         return 0;
1292
1293 out_reg:
1294         init_completion(&adap->dev_released);
1295         device_unregister(&adap->dev);
1296         wait_for_completion(&adap->dev_released);
1297 out_list:
1298         mutex_lock(&core_lock);
1299         idr_remove(&i2c_adapter_idr, adap->nr);
1300         mutex_unlock(&core_lock);
1301         return res;
1302 }
1303
1304 /**
1305  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1306  * @adap: the adapter to register (with adap->nr initialized)
1307  * Context: can sleep
1308  *
1309  * See i2c_add_numbered_adapter() for details.
1310  */
1311 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1312 {
1313         int id;
1314
1315         mutex_lock(&core_lock);
1316         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1317         mutex_unlock(&core_lock);
1318         if (WARN(id < 0, "couldn't get idr"))
1319                 return id == -ENOSPC ? -EBUSY : id;
1320
1321         return i2c_register_adapter(adap);
1322 }
1323
1324 /**
1325  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1326  * @adapter: the adapter to add
1327  * Context: can sleep
1328  *
1329  * This routine is used to declare an I2C adapter when its bus number
1330  * doesn't matter or when its bus number is specified by an dt alias.
1331  * Examples of bases when the bus number doesn't matter: I2C adapters
1332  * dynamically added by USB links or PCI plugin cards.
1333  *
1334  * When this returns zero, a new bus number was allocated and stored
1335  * in adap->nr, and the specified adapter became available for clients.
1336  * Otherwise, a negative errno value is returned.
1337  */
1338 int i2c_add_adapter(struct i2c_adapter *adapter)
1339 {
1340         struct device *dev = &adapter->dev;
1341         int id;
1342
1343         if (dev->of_node) {
1344                 id = of_alias_get_id(dev->of_node, "i2c");
1345                 if (id >= 0) {
1346                         adapter->nr = id;
1347                         return __i2c_add_numbered_adapter(adapter);
1348                 }
1349         }
1350
1351         mutex_lock(&core_lock);
1352         id = idr_alloc(&i2c_adapter_idr, adapter,
1353                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1354         mutex_unlock(&core_lock);
1355         if (WARN(id < 0, "couldn't get idr"))
1356                 return id;
1357
1358         adapter->nr = id;
1359
1360         return i2c_register_adapter(adapter);
1361 }
1362 EXPORT_SYMBOL(i2c_add_adapter);
1363
1364 /**
1365  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1366  * @adap: the adapter to register (with adap->nr initialized)
1367  * Context: can sleep
1368  *
1369  * This routine is used to declare an I2C adapter when its bus number
1370  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1371  * or otherwise built in to the system's mainboard, and where i2c_board_info
1372  * is used to properly configure I2C devices.
1373  *
1374  * If the requested bus number is set to -1, then this function will behave
1375  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1376  *
1377  * If no devices have pre-been declared for this bus, then be sure to
1378  * register the adapter before any dynamically allocated ones.  Otherwise
1379  * the required bus ID may not be available.
1380  *
1381  * When this returns zero, the specified adapter became available for
1382  * clients using the bus number provided in adap->nr.  Also, the table
1383  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1384  * and the appropriate driver model device nodes are created.  Otherwise, a
1385  * negative errno value is returned.
1386  */
1387 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1388 {
1389         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1390                 return i2c_add_adapter(adap);
1391
1392         return __i2c_add_numbered_adapter(adap);
1393 }
1394 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1395
1396 static void i2c_do_del_adapter(struct i2c_driver *driver,
1397                               struct i2c_adapter *adapter)
1398 {
1399         struct i2c_client *client, *_n;
1400
1401         /* Remove the devices we created ourselves as the result of hardware
1402          * probing (using a driver's detect method) */
1403         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1404                 if (client->adapter == adapter) {
1405                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1406                                 client->name, client->addr);
1407                         list_del(&client->detected);
1408                         i2c_unregister_device(client);
1409                 }
1410         }
1411 }
1412
1413 static int __unregister_client(struct device *dev, void *dummy)
1414 {
1415         struct i2c_client *client = i2c_verify_client(dev);
1416         if (client && strcmp(client->name, "dummy"))
1417                 i2c_unregister_device(client);
1418         return 0;
1419 }
1420
1421 static int __unregister_dummy(struct device *dev, void *dummy)
1422 {
1423         struct i2c_client *client = i2c_verify_client(dev);
1424         i2c_unregister_device(client);
1425         return 0;
1426 }
1427
1428 static int __process_removed_adapter(struct device_driver *d, void *data)
1429 {
1430         i2c_do_del_adapter(to_i2c_driver(d), data);
1431         return 0;
1432 }
1433
1434 /**
1435  * i2c_del_adapter - unregister I2C adapter
1436  * @adap: the adapter being unregistered
1437  * Context: can sleep
1438  *
1439  * This unregisters an I2C adapter which was previously registered
1440  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1441  */
1442 void i2c_del_adapter(struct i2c_adapter *adap)
1443 {
1444         struct i2c_adapter *found;
1445         struct i2c_client *client, *next;
1446
1447         /* First make sure that this adapter was ever added */
1448         mutex_lock(&core_lock);
1449         found = idr_find(&i2c_adapter_idr, adap->nr);
1450         mutex_unlock(&core_lock);
1451         if (found != adap) {
1452                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1453                 return;
1454         }
1455
1456         i2c_acpi_remove_space_handler(adap);
1457         /* Tell drivers about this removal */
1458         mutex_lock(&core_lock);
1459         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1460                                __process_removed_adapter);
1461         mutex_unlock(&core_lock);
1462
1463         /* Remove devices instantiated from sysfs */
1464         mutex_lock_nested(&adap->userspace_clients_lock,
1465                           i2c_adapter_depth(adap));
1466         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1467                                  detected) {
1468                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1469                         client->addr);
1470                 list_del(&client->detected);
1471                 i2c_unregister_device(client);
1472         }
1473         mutex_unlock(&adap->userspace_clients_lock);
1474
1475         /* Detach any active clients. This can't fail, thus we do not
1476          * check the returned value. This is a two-pass process, because
1477          * we can't remove the dummy devices during the first pass: they
1478          * could have been instantiated by real devices wishing to clean
1479          * them up properly, so we give them a chance to do that first. */
1480         device_for_each_child(&adap->dev, NULL, __unregister_client);
1481         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1482
1483 #ifdef CONFIG_I2C_COMPAT
1484         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1485                                  adap->dev.parent);
1486 #endif
1487
1488         /* device name is gone after device_unregister */
1489         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1490
1491         pm_runtime_disable(&adap->dev);
1492
1493         i2c_host_notify_irq_teardown(adap);
1494
1495         /* wait until all references to the device are gone
1496          *
1497          * FIXME: This is old code and should ideally be replaced by an
1498          * alternative which results in decoupling the lifetime of the struct
1499          * device from the i2c_adapter, like spi or netdev do. Any solution
1500          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1501          */
1502         init_completion(&adap->dev_released);
1503         device_unregister(&adap->dev);
1504         wait_for_completion(&adap->dev_released);
1505
1506         /* free bus id */
1507         mutex_lock(&core_lock);
1508         idr_remove(&i2c_adapter_idr, adap->nr);
1509         mutex_unlock(&core_lock);
1510
1511         /* Clear the device structure in case this adapter is ever going to be
1512            added again */
1513         memset(&adap->dev, 0, sizeof(adap->dev));
1514 }
1515 EXPORT_SYMBOL(i2c_del_adapter);
1516
1517 /**
1518  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1519  * @dev: The device to scan for I2C timing properties
1520  * @t: the i2c_timings struct to be filled with values
1521  * @use_defaults: bool to use sane defaults derived from the I2C specification
1522  *                when properties are not found, otherwise use 0
1523  *
1524  * Scan the device for the generic I2C properties describing timing parameters
1525  * for the signal and fill the given struct with the results. If a property was
1526  * not found and use_defaults was true, then maximum timings are assumed which
1527  * are derived from the I2C specification. If use_defaults is not used, the
1528  * results will be 0, so drivers can apply their own defaults later. The latter
1529  * is mainly intended for avoiding regressions of existing drivers which want
1530  * to switch to this function. New drivers almost always should use the defaults.
1531  */
1532
1533 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1534 {
1535         int ret;
1536
1537         memset(t, 0, sizeof(*t));
1538
1539         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1540         if (ret && use_defaults)
1541                 t->bus_freq_hz = 100000;
1542
1543         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1544         if (ret && use_defaults) {
1545                 if (t->bus_freq_hz <= 100000)
1546                         t->scl_rise_ns = 1000;
1547                 else if (t->bus_freq_hz <= 400000)
1548                         t->scl_rise_ns = 300;
1549                 else
1550                         t->scl_rise_ns = 120;
1551         }
1552
1553         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1554         if (ret && use_defaults) {
1555                 if (t->bus_freq_hz <= 400000)
1556                         t->scl_fall_ns = 300;
1557                 else
1558                         t->scl_fall_ns = 120;
1559         }
1560
1561         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1562
1563         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1564         if (ret && use_defaults)
1565                 t->sda_fall_ns = t->scl_fall_ns;
1566 }
1567 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1568
1569 /* ------------------------------------------------------------------------- */
1570
1571 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1572 {
1573         int res;
1574
1575         mutex_lock(&core_lock);
1576         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1577         mutex_unlock(&core_lock);
1578
1579         return res;
1580 }
1581 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1582
1583 static int __process_new_driver(struct device *dev, void *data)
1584 {
1585         if (dev->type != &i2c_adapter_type)
1586                 return 0;
1587         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1588 }
1589
1590 /*
1591  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1592  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1593  */
1594
1595 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1596 {
1597         int res;
1598
1599         /* Can't register until after driver model init */
1600         if (WARN_ON(!is_registered))
1601                 return -EAGAIN;
1602
1603         /* add the driver to the list of i2c drivers in the driver core */
1604         driver->driver.owner = owner;
1605         driver->driver.bus = &i2c_bus_type;
1606         INIT_LIST_HEAD(&driver->clients);
1607
1608         /* When registration returns, the driver core
1609          * will have called probe() for all matching-but-unbound devices.
1610          */
1611         res = driver_register(&driver->driver);
1612         if (res)
1613                 return res;
1614
1615         pr_debug("driver [%s] registered\n", driver->driver.name);
1616
1617         /* Walk the adapters that are already present */
1618         i2c_for_each_dev(driver, __process_new_driver);
1619
1620         return 0;
1621 }
1622 EXPORT_SYMBOL(i2c_register_driver);
1623
1624 static int __process_removed_driver(struct device *dev, void *data)
1625 {
1626         if (dev->type == &i2c_adapter_type)
1627                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1628         return 0;
1629 }
1630
1631 /**
1632  * i2c_del_driver - unregister I2C driver
1633  * @driver: the driver being unregistered
1634  * Context: can sleep
1635  */
1636 void i2c_del_driver(struct i2c_driver *driver)
1637 {
1638         i2c_for_each_dev(driver, __process_removed_driver);
1639
1640         driver_unregister(&driver->driver);
1641         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1642 }
1643 EXPORT_SYMBOL(i2c_del_driver);
1644
1645 /* ------------------------------------------------------------------------- */
1646
1647 /**
1648  * i2c_use_client - increments the reference count of the i2c client structure
1649  * @client: the client being referenced
1650  *
1651  * Each live reference to a client should be refcounted. The driver model does
1652  * that automatically as part of driver binding, so that most drivers don't
1653  * need to do this explicitly: they hold a reference until they're unbound
1654  * from the device.
1655  *
1656  * A pointer to the client with the incremented reference counter is returned.
1657  */
1658 struct i2c_client *i2c_use_client(struct i2c_client *client)
1659 {
1660         if (client && get_device(&client->dev))
1661                 return client;
1662         return NULL;
1663 }
1664 EXPORT_SYMBOL(i2c_use_client);
1665
1666 /**
1667  * i2c_release_client - release a use of the i2c client structure
1668  * @client: the client being no longer referenced
1669  *
1670  * Must be called when a user of a client is finished with it.
1671  */
1672 void i2c_release_client(struct i2c_client *client)
1673 {
1674         if (client)
1675                 put_device(&client->dev);
1676 }
1677 EXPORT_SYMBOL(i2c_release_client);
1678
1679 struct i2c_cmd_arg {
1680         unsigned        cmd;
1681         void            *arg;
1682 };
1683
1684 static int i2c_cmd(struct device *dev, void *_arg)
1685 {
1686         struct i2c_client       *client = i2c_verify_client(dev);
1687         struct i2c_cmd_arg      *arg = _arg;
1688         struct i2c_driver       *driver;
1689
1690         if (!client || !client->dev.driver)
1691                 return 0;
1692
1693         driver = to_i2c_driver(client->dev.driver);
1694         if (driver->command)
1695                 driver->command(client, arg->cmd, arg->arg);
1696         return 0;
1697 }
1698
1699 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1700 {
1701         struct i2c_cmd_arg      cmd_arg;
1702
1703         cmd_arg.cmd = cmd;
1704         cmd_arg.arg = arg;
1705         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1706 }
1707 EXPORT_SYMBOL(i2c_clients_command);
1708
1709 static int __init i2c_init(void)
1710 {
1711         int retval;
1712
1713         retval = of_alias_get_highest_id("i2c");
1714
1715         down_write(&__i2c_board_lock);
1716         if (retval >= __i2c_first_dynamic_bus_num)
1717                 __i2c_first_dynamic_bus_num = retval + 1;
1718         up_write(&__i2c_board_lock);
1719
1720         retval = bus_register(&i2c_bus_type);
1721         if (retval)
1722                 return retval;
1723
1724         is_registered = true;
1725
1726 #ifdef CONFIG_I2C_COMPAT
1727         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1728         if (!i2c_adapter_compat_class) {
1729                 retval = -ENOMEM;
1730                 goto bus_err;
1731         }
1732 #endif
1733         retval = i2c_add_driver(&dummy_driver);
1734         if (retval)
1735                 goto class_err;
1736
1737         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1738                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1739         if (IS_ENABLED(CONFIG_ACPI))
1740                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1741
1742         return 0;
1743
1744 class_err:
1745 #ifdef CONFIG_I2C_COMPAT
1746         class_compat_unregister(i2c_adapter_compat_class);
1747 bus_err:
1748 #endif
1749         is_registered = false;
1750         bus_unregister(&i2c_bus_type);
1751         return retval;
1752 }
1753
1754 static void __exit i2c_exit(void)
1755 {
1756         if (IS_ENABLED(CONFIG_ACPI))
1757                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1758         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1759                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1760         i2c_del_driver(&dummy_driver);
1761 #ifdef CONFIG_I2C_COMPAT
1762         class_compat_unregister(i2c_adapter_compat_class);
1763 #endif
1764         bus_unregister(&i2c_bus_type);
1765         tracepoint_synchronize_unregister();
1766 }
1767
1768 /* We must initialize early, because some subsystems register i2c drivers
1769  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1770  */
1771 postcore_initcall(i2c_init);
1772 module_exit(i2c_exit);
1773
1774 /* ----------------------------------------------------
1775  * the functional interface to the i2c busses.
1776  * ----------------------------------------------------
1777  */
1778
1779 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1780 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1781
1782 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1783 {
1784         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1785                             err_msg, msg->addr, msg->len,
1786                             msg->flags & I2C_M_RD ? "read" : "write");
1787         return -EOPNOTSUPP;
1788 }
1789
1790 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1791 {
1792         const struct i2c_adapter_quirks *q = adap->quirks;
1793         int max_num = q->max_num_msgs, i;
1794         bool do_len_check = true;
1795
1796         if (q->flags & I2C_AQ_COMB) {
1797                 max_num = 2;
1798
1799                 /* special checks for combined messages */
1800                 if (num == 2) {
1801                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1802                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1803
1804                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1805                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1806
1807                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1808                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1809
1810                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1811                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1812
1813                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1814                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1815
1816                         do_len_check = false;
1817                 }
1818         }
1819
1820         if (i2c_quirk_exceeded(num, max_num))
1821                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1822
1823         for (i = 0; i < num; i++) {
1824                 u16 len = msgs[i].len;
1825
1826                 if (msgs[i].flags & I2C_M_RD) {
1827                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1828                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1829                 } else {
1830                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1831                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1832                 }
1833         }
1834
1835         return 0;
1836 }
1837
1838 /**
1839  * __i2c_transfer - unlocked flavor of i2c_transfer
1840  * @adap: Handle to I2C bus
1841  * @msgs: One or more messages to execute before STOP is issued to
1842  *      terminate the operation; each message begins with a START.
1843  * @num: Number of messages to be executed.
1844  *
1845  * Returns negative errno, else the number of messages executed.
1846  *
1847  * Adapter lock must be held when calling this function. No debug logging
1848  * takes place. adap->algo->master_xfer existence isn't checked.
1849  */
1850 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1851 {
1852         unsigned long orig_jiffies;
1853         int ret, try;
1854
1855         if (WARN_ON(!msgs || num < 1))
1856                 return -EINVAL;
1857
1858         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1859                 return -EOPNOTSUPP;
1860
1861         /*
1862          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1863          * enabled.  This is an efficient way of keeping the for-loop from
1864          * being executed when not needed.
1865          */
1866         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1867                 int i;
1868                 for (i = 0; i < num; i++)
1869                         if (msgs[i].flags & I2C_M_RD)
1870                                 trace_i2c_read(adap, &msgs[i], i);
1871                         else
1872                                 trace_i2c_write(adap, &msgs[i], i);
1873         }
1874
1875         /* Retry automatically on arbitration loss */
1876         orig_jiffies = jiffies;
1877         for (ret = 0, try = 0; try <= adap->retries; try++) {
1878                 ret = adap->algo->master_xfer(adap, msgs, num);
1879                 if (ret != -EAGAIN)
1880                         break;
1881                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1882                         break;
1883         }
1884
1885         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1886                 int i;
1887                 for (i = 0; i < ret; i++)
1888                         if (msgs[i].flags & I2C_M_RD)
1889                                 trace_i2c_reply(adap, &msgs[i], i);
1890                 trace_i2c_result(adap, num, ret);
1891         }
1892
1893         return ret;
1894 }
1895 EXPORT_SYMBOL(__i2c_transfer);
1896
1897 /**
1898  * i2c_transfer - execute a single or combined I2C message
1899  * @adap: Handle to I2C bus
1900  * @msgs: One or more messages to execute before STOP is issued to
1901  *      terminate the operation; each message begins with a START.
1902  * @num: Number of messages to be executed.
1903  *
1904  * Returns negative errno, else the number of messages executed.
1905  *
1906  * Note that there is no requirement that each message be sent to
1907  * the same slave address, although that is the most common model.
1908  */
1909 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1910 {
1911         int ret;
1912
1913         /* REVISIT the fault reporting model here is weak:
1914          *
1915          *  - When we get an error after receiving N bytes from a slave,
1916          *    there is no way to report "N".
1917          *
1918          *  - When we get a NAK after transmitting N bytes to a slave,
1919          *    there is no way to report "N" ... or to let the master
1920          *    continue executing the rest of this combined message, if
1921          *    that's the appropriate response.
1922          *
1923          *  - When for example "num" is two and we successfully complete
1924          *    the first message but get an error part way through the
1925          *    second, it's unclear whether that should be reported as
1926          *    one (discarding status on the second message) or errno
1927          *    (discarding status on the first one).
1928          */
1929
1930         if (adap->algo->master_xfer) {
1931 #ifdef DEBUG
1932                 for (ret = 0; ret < num; ret++) {
1933                         dev_dbg(&adap->dev,
1934                                 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1935                                 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1936                                 msgs[ret].addr, msgs[ret].len,
1937                                 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1938                 }
1939 #endif
1940
1941                 if (in_atomic() || irqs_disabled()) {
1942                         ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1943                         if (!ret)
1944                                 /* I2C activity is ongoing. */
1945                                 return -EAGAIN;
1946                 } else {
1947                         i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1948                 }
1949
1950                 ret = __i2c_transfer(adap, msgs, num);
1951                 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1952
1953                 return ret;
1954         } else {
1955                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1956                 return -EOPNOTSUPP;
1957         }
1958 }
1959 EXPORT_SYMBOL(i2c_transfer);
1960
1961 /**
1962  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1963  *                             to/from a buffer
1964  * @client: Handle to slave device
1965  * @buf: Where the data is stored
1966  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1967  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1968  *
1969  * Returns negative errno, or else the number of bytes transferred.
1970  */
1971 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1972                               int count, u16 flags)
1973 {
1974         int ret;
1975         struct i2c_msg msg = {
1976                 .addr = client->addr,
1977                 .flags = flags | (client->flags & I2C_M_TEN),
1978                 .len = count,
1979                 .buf = buf,
1980         };
1981
1982         ret = i2c_transfer(client->adapter, &msg, 1);
1983
1984         /*
1985          * If everything went ok (i.e. 1 msg transferred), return #bytes
1986          * transferred, else error code.
1987          */
1988         return (ret == 1) ? count : ret;
1989 }
1990 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1991
1992 /**
1993  * i2c_get_device_id - get manufacturer, part id and die revision of a device
1994  * @client: The device to query
1995  * @id: The queried information
1996  *
1997  * Returns negative errno on error, zero on success.
1998  */
1999 int i2c_get_device_id(const struct i2c_client *client,
2000                       struct i2c_device_identity *id)
2001 {
2002         struct i2c_adapter *adap = client->adapter;
2003         union i2c_smbus_data raw_id;
2004         int ret;
2005
2006         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2007                 return -EOPNOTSUPP;
2008
2009         raw_id.block[0] = 3;
2010         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2011                              I2C_SMBUS_READ, client->addr << 1,
2012                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2013         if (ret)
2014                 return ret;
2015
2016         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2017         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2018         id->die_revision = raw_id.block[3] & 0x7;
2019         return 0;
2020 }
2021 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2022
2023 /* ----------------------------------------------------
2024  * the i2c address scanning function
2025  * Will not work for 10-bit addresses!
2026  * ----------------------------------------------------
2027  */
2028
2029 /*
2030  * Legacy default probe function, mostly relevant for SMBus. The default
2031  * probe method is a quick write, but it is known to corrupt the 24RF08
2032  * EEPROMs due to a state machine bug, and could also irreversibly
2033  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2034  * we use a short byte read instead. Also, some bus drivers don't implement
2035  * quick write, so we fallback to a byte read in that case too.
2036  * On x86, there is another special case for FSC hardware monitoring chips,
2037  * which want regular byte reads (address 0x73.) Fortunately, these are the
2038  * only known chips using this I2C address on PC hardware.
2039  * Returns 1 if probe succeeded, 0 if not.
2040  */
2041 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2042 {
2043         int err;
2044         union i2c_smbus_data dummy;
2045
2046 #ifdef CONFIG_X86
2047         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2048          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2049                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2050                                      I2C_SMBUS_BYTE_DATA, &dummy);
2051         else
2052 #endif
2053         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2054          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2055                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2056                                      I2C_SMBUS_QUICK, NULL);
2057         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2058                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2059                                      I2C_SMBUS_BYTE, &dummy);
2060         else {
2061                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2062                          addr);
2063                 err = -EOPNOTSUPP;
2064         }
2065
2066         return err >= 0;
2067 }
2068
2069 static int i2c_detect_address(struct i2c_client *temp_client,
2070                               struct i2c_driver *driver)
2071 {
2072         struct i2c_board_info info;
2073         struct i2c_adapter *adapter = temp_client->adapter;
2074         int addr = temp_client->addr;
2075         int err;
2076
2077         /* Make sure the address is valid */
2078         err = i2c_check_7bit_addr_validity_strict(addr);
2079         if (err) {
2080                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2081                          addr);
2082                 return err;
2083         }
2084
2085         /* Skip if already in use (7 bit, no need to encode flags) */
2086         if (i2c_check_addr_busy(adapter, addr))
2087                 return 0;
2088
2089         /* Make sure there is something at this address */
2090         if (!i2c_default_probe(adapter, addr))
2091                 return 0;
2092
2093         /* Finally call the custom detection function */
2094         memset(&info, 0, sizeof(struct i2c_board_info));
2095         info.addr = addr;
2096         err = driver->detect(temp_client, &info);
2097         if (err) {
2098                 /* -ENODEV is returned if the detection fails. We catch it
2099                    here as this isn't an error. */
2100                 return err == -ENODEV ? 0 : err;
2101         }
2102
2103         /* Consistency check */
2104         if (info.type[0] == '\0') {
2105                 dev_err(&adapter->dev,
2106                         "%s detection function provided no name for 0x%x\n",
2107                         driver->driver.name, addr);
2108         } else {
2109                 struct i2c_client *client;
2110
2111                 /* Detection succeeded, instantiate the device */
2112                 if (adapter->class & I2C_CLASS_DEPRECATED)
2113                         dev_warn(&adapter->dev,
2114                                 "This adapter will soon drop class based instantiation of devices. "
2115                                 "Please make sure client 0x%02x gets instantiated by other means. "
2116                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2117                                 info.addr);
2118
2119                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2120                         info.type, info.addr);
2121                 client = i2c_new_device(adapter, &info);
2122                 if (client)
2123                         list_add_tail(&client->detected, &driver->clients);
2124                 else
2125                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2126                                 info.type, info.addr);
2127         }
2128         return 0;
2129 }
2130
2131 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2132 {
2133         const unsigned short *address_list;
2134         struct i2c_client *temp_client;
2135         int i, err = 0;
2136         int adap_id = i2c_adapter_id(adapter);
2137
2138         address_list = driver->address_list;
2139         if (!driver->detect || !address_list)
2140                 return 0;
2141
2142         /* Warn that the adapter lost class based instantiation */
2143         if (adapter->class == I2C_CLASS_DEPRECATED) {
2144                 dev_dbg(&adapter->dev,
2145                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2146                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2147                         driver->driver.name);
2148                 return 0;
2149         }
2150
2151         /* Stop here if the classes do not match */
2152         if (!(adapter->class & driver->class))
2153                 return 0;
2154
2155         /* Set up a temporary client to help detect callback */
2156         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2157         if (!temp_client)
2158                 return -ENOMEM;
2159         temp_client->adapter = adapter;
2160
2161         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2162                 dev_dbg(&adapter->dev,
2163                         "found normal entry for adapter %d, addr 0x%02x\n",
2164                         adap_id, address_list[i]);
2165                 temp_client->addr = address_list[i];
2166                 err = i2c_detect_address(temp_client, driver);
2167                 if (unlikely(err))
2168                         break;
2169         }
2170
2171         kfree(temp_client);
2172         return err;
2173 }
2174
2175 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2176 {
2177         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2178                               I2C_SMBUS_QUICK, NULL) >= 0;
2179 }
2180 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2181
2182 struct i2c_client *
2183 i2c_new_probed_device(struct i2c_adapter *adap,
2184                       struct i2c_board_info *info,
2185                       unsigned short const *addr_list,
2186                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2187 {
2188         int i;
2189
2190         if (!probe)
2191                 probe = i2c_default_probe;
2192
2193         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2194                 /* Check address validity */
2195                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2196                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2197                                  addr_list[i]);
2198                         continue;
2199                 }
2200
2201                 /* Check address availability (7 bit, no need to encode flags) */
2202                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2203                         dev_dbg(&adap->dev,
2204                                 "Address 0x%02x already in use, not probing\n",
2205                                 addr_list[i]);
2206                         continue;
2207                 }
2208
2209                 /* Test address responsiveness */
2210                 if (probe(adap, addr_list[i]))
2211                         break;
2212         }
2213
2214         if (addr_list[i] == I2C_CLIENT_END) {
2215                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2216                 return NULL;
2217         }
2218
2219         info->addr = addr_list[i];
2220         return i2c_new_device(adap, info);
2221 }
2222 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2223
2224 struct i2c_adapter *i2c_get_adapter(int nr)
2225 {
2226         struct i2c_adapter *adapter;
2227
2228         mutex_lock(&core_lock);
2229         adapter = idr_find(&i2c_adapter_idr, nr);
2230         if (!adapter)
2231                 goto exit;
2232
2233         if (try_module_get(adapter->owner))
2234                 get_device(&adapter->dev);
2235         else
2236                 adapter = NULL;
2237
2238  exit:
2239         mutex_unlock(&core_lock);
2240         return adapter;
2241 }
2242 EXPORT_SYMBOL(i2c_get_adapter);
2243
2244 void i2c_put_adapter(struct i2c_adapter *adap)
2245 {
2246         if (!adap)
2247                 return;
2248
2249         put_device(&adap->dev);
2250         module_put(adap->owner);
2251 }
2252 EXPORT_SYMBOL(i2c_put_adapter);
2253
2254 /**
2255  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2256  * @msg: the message to be checked
2257  * @threshold: the minimum number of bytes for which using DMA makes sense
2258  *
2259  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2260  *         Or a valid pointer to be used with DMA. After use, release it by
2261  *         calling i2c_release_dma_safe_msg_buf().
2262  *
2263  * This function must only be called from process context!
2264  */
2265 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2266 {
2267         if (msg->len < threshold)
2268                 return NULL;
2269
2270         if (msg->flags & I2C_M_DMA_SAFE)
2271                 return msg->buf;
2272
2273         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2274                  msg->addr, msg->len);
2275
2276         if (msg->flags & I2C_M_RD)
2277                 return kzalloc(msg->len, GFP_KERNEL);
2278         else
2279                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2280 }
2281 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2282
2283 /**
2284  * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2285  * @msg: the message to be synced with
2286  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2287  */
2288 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2289 {
2290         if (!buf || buf == msg->buf)
2291                 return;
2292
2293         if (msg->flags & I2C_M_RD)
2294                 memcpy(msg->buf, buf, msg->len);
2295
2296         kfree(buf);
2297 }
2298 EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2299
2300 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2301 MODULE_DESCRIPTION("I2C-Bus main module");
2302 MODULE_LICENSE("GPL");