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 = 0;
 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->irq = info->irq;
 745         if (!client->irq)
 746                 client->irq = i2c_dev_irq_from_resources(info->resources,
 747                                                          info->num_resources);
 748
 749         strlcpy(client->name, info->type, sizeof(client->name));
 750
 751         status = i2c_check_addr_validity(client->addr, client->flags);
 752         if (status) {
 753                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 754                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 755                 goto out_err_silent;
 756         }
 757
 758         /* Check for address business */
 759         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 760         if (status)
 761                 goto out_err;
 762
 763         client->dev.parent = &client->adapter->dev;
 764         client->dev.bus = &i2c_bus_type;
 765         client->dev.type = &i2c_client_type;
 766         client->dev.of_node = of_node_get(info->of_node);
 767         client->dev.fwnode = info->fwnode;
 768
 769         i2c_dev_set_name(adap, client, info);
 770
 771         if (info->properties) {
 772                 status = device_add_properties(&client->dev, info->properties);
 773                 if (status) {
 774                         dev_err(&adap->dev,
 775                                 "Failed to add properties to client %s: %d\n",
 776                                 client->name, status);
 777                         goto out_err_put_of_node;
 778                 }
 779         }
 780
 781         status = device_register(&client->dev);
 782         if (status)
 783                 goto out_free_props;
 784
 785         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 786                 client->name, dev_name(&client->dev));
 787
 788         return client;
 789
 790 out_free_props:
 791         if (info->properties)
 792                 device_remove_properties(&client->dev);
 793 out_err_put_of_node:
 794         of_node_put(info->of_node);
 795 out_err:
 796         dev_err(&adap->dev,
 797                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 798                 client->name, client->addr, status);
 799 out_err_silent:
 800         kfree(client);
 801         return NULL;
 802 }
 803 EXPORT_SYMBOL_GPL(i2c_new_device);
 804
 805
 806 /**
 807  * i2c_unregister_device - reverse effect of i2c_new_device()
 808  * @client: value returned from i2c_new_device()
 809  * Context: can sleep
 810  */
 811 void i2c_unregister_device(struct i2c_client *client)
 812 {
 813         if (!client)
 814                 return;
 815
 816         if (client->dev.of_node) {
 817                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 818                 of_node_put(client->dev.of_node);
 819         }
 820
 821         if (ACPI_COMPANION(&client->dev))
 822                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 823         device_unregister(&client->dev);
 824 }
 825 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 826
 827
 828 static const struct i2c_device_id dummy_id[] = {
 829         { "dummy", 0 },
 830         { },
 831 };
 832
 833 static int dummy_probe(struct i2c_client *client,
 834                        const struct i2c_device_id *id)
 835 {
 836         return 0;
 837 }
 838
 839 static int dummy_remove(struct i2c_client *client)
 840 {
 841         return 0;
 842 }
 843
 844 static struct i2c_driver dummy_driver = {
 845         .driver.name    = "dummy",
 846         .probe          = dummy_probe,
 847         .remove         = dummy_remove,
 848         .id_table       = dummy_id,
 849 };
 850
 851 /**
 852  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 853  * @adapter: the adapter managing the device
 854  * @address: seven bit address to be used
 855  * Context: can sleep
 856  *
 857  * This returns an I2C client bound to the "dummy" driver, intended for use
 858  * with devices that consume multiple addresses.  Examples of such chips
 859  * include various EEPROMS (like 24c04 and 24c08 models).
 860  *
 861  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 862  * except i2c_transfer() need a client handle; the dummy will be that handle.
 863  * And second, this prevents the specified address from being bound to a
 864  * different driver.
 865  *
 866  * This returns the new i2c client, which should be saved for later use with
 867  * i2c_unregister_device(); or NULL to indicate an error.
 868  */
 869 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 870 {
 871         struct i2c_board_info info = {
 872                 I2C_BOARD_INFO("dummy", address),
 873         };
 874
 875         return i2c_new_device(adapter, &info);
 876 }
 877 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 878
 879 /**
 880  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 881  * and create the associated device
 882  * @client: Handle to the primary client
 883  * @name: Handle to specify which secondary address to get
 884  * @default_addr: Used as a fallback if no secondary address was specified
 885  * Context: can sleep
 886  *
 887  * I2C clients can be composed of multiple I2C slaves bound together in a single
 888  * component. The I2C client driver then binds to the master I2C slave and needs
 889  * to create I2C dummy clients to communicate with all the other slaves.
 890  *
 891  * This function creates and returns an I2C dummy client whose I2C address is
 892  * retrieved from the platform firmware based on the given slave name. If no
 893  * address is specified by the firmware default_addr is used.
 894  *
 895  * On DT-based platforms the address is retrieved from the "reg" property entry
 896  * cell whose "reg-names" value matches the slave name.
 897  *
 898  * This returns the new i2c client, which should be saved for later use with
 899  * i2c_unregister_device(); or NULL to indicate an error.
 900  */
 901 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 902                                                 const char *name,
 903                                                 u16 default_addr)
 904 {
 905         struct device_node *np = client->dev.of_node;
 906         u32 addr = default_addr;
 907         int i;
 908
 909         if (np) {
 910                 i = of_property_match_string(np, "reg-names", name);
 911                 if (i >= 0)
 912                         of_property_read_u32_index(np, "reg", i, &addr);
 913         }
 914
 915         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 916         return i2c_new_dummy(client->adapter, addr);
 917 }
 918 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 919
 920 /* ------------------------------------------------------------------------- */
 921
 922 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 923
 924 static void i2c_adapter_dev_release(struct device *dev)
 925 {
 926         struct i2c_adapter *adap = to_i2c_adapter(dev);
 927         complete(&adap->dev_released);
 928 }
 929
 930 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 931 {
 932         unsigned int depth = 0;
 933
 934         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 935                 depth++;
 936
 937         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 938                   "adapter depth exceeds lockdep subclass limit\n");
 939
 940         return depth;
 941 }
 942 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 943
 944 /*
 945  * Let users instantiate I2C devices through sysfs. This can be used when
 946  * platform initialization code doesn't contain the proper data for
 947  * whatever reason. Also useful for drivers that do device detection and
 948  * detection fails, either because the device uses an unexpected address,
 949  * or this is a compatible device with different ID register values.
 950  *
 951  * Parameter checking may look overzealous, but we really don't want
 952  * the user to provide incorrect parameters.
 953  */
 954 static ssize_t
 955 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 956                      const char *buf, size_t count)
 957 {
 958         struct i2c_adapter *adap = to_i2c_adapter(dev);
 959         struct i2c_board_info info;
 960         struct i2c_client *client;
 961         char *blank, end;
 962         int res;
 963
 964         memset(&info, 0, sizeof(struct i2c_board_info));
 965
 966         blank = strchr(buf, ' ');
 967         if (!blank) {
 968                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 969                 return -EINVAL;
 970         }
 971         if (blank - buf > I2C_NAME_SIZE - 1) {
 972                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 973                 return -EINVAL;
 974         }
 975         memcpy(info.type, buf, blank - buf);
 976
 977         /* Parse remaining parameters, reject extra parameters */
 978         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 979         if (res < 1) {
 980                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 981                 return -EINVAL;
 982         }
 983         if (res > 1  && end != '\n') {
 984                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 985                 return -EINVAL;
 986         }
 987
 988         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 989                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 990                 info.flags |= I2C_CLIENT_TEN;
 991         }
 992
 993         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 994                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 995                 info.flags |= I2C_CLIENT_SLAVE;
 996         }
 997
 998         client = i2c_new_device(adap, &info);
 999         if (!client)
1000                 return -EINVAL;
1001
1002         /* Keep track of the added device */
1003         mutex_lock(&adap->userspace_clients_lock);
1004         list_add_tail(&client->detected, &adap->userspace_clients);
1005         mutex_unlock(&adap->userspace_clients_lock);
1006         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1007                  info.type, info.addr);
1008
1009         return count;
1010 }
1011 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1012
1013 /*
1014  * And of course let the users delete the devices they instantiated, if
1015  * they got it wrong. This interface can only be used to delete devices
1016  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1017  * don't delete devices to which some kernel code still has references.
1018  *
1019  * Parameter checking may look overzealous, but we really don't want
1020  * the user to delete the wrong device.
1021  */
1022 static ssize_t
1023 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1024                         const char *buf, size_t count)
1025 {
1026         struct i2c_adapter *adap = to_i2c_adapter(dev);
1027         struct i2c_client *client, *next;
1028         unsigned short addr;
1029         char end;
1030         int res;
1031
1032         /* Parse parameters, reject extra parameters */
1033         res = sscanf(buf, "%hi%c", &addr, &end);
1034         if (res < 1) {
1035                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1036                 return -EINVAL;
1037         }
1038         if (res > 1  && end != '\n') {
1039                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1040                 return -EINVAL;
1041         }
1042
1043         /* Make sure the device was added through sysfs */
1044         res = -ENOENT;
1045         mutex_lock_nested(&adap->userspace_clients_lock,
1046                           i2c_adapter_depth(adap));
1047         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1048                                  detected) {
1049                 if (i2c_encode_flags_to_addr(client) == addr) {
1050                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1051                                  "delete_device", client->name, client->addr);
1052
1053                         list_del(&client->detected);
1054                         i2c_unregister_device(client);
1055                         res = count;
1056                         break;
1057                 }
1058         }
1059         mutex_unlock(&adap->userspace_clients_lock);
1060
1061         if (res < 0)
1062                 dev_err(dev, "%s: Can't find device in list\n",
1063                         "delete_device");
1064         return res;
1065 }
1066 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1067                                    i2c_sysfs_delete_device);
1068
1069 static struct attribute *i2c_adapter_attrs[] = {
1070         &dev_attr_name.attr,
1071         &dev_attr_new_device.attr,
1072         &dev_attr_delete_device.attr,
1073         NULL
1074 };
1075 ATTRIBUTE_GROUPS(i2c_adapter);
1076
1077 struct device_type i2c_adapter_type = {
1078         .groups         = i2c_adapter_groups,
1079         .release        = i2c_adapter_dev_release,
1080 };
1081 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1082
1083 /**
1084  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1085  * @dev: device, probably from some driver model iterator
1086  *
1087  * When traversing the driver model tree, perhaps using driver model
1088  * iterators like @device_for_each_child(), you can't assume very much
1089  * about the nodes you find.  Use this function to avoid oopses caused
1090  * by wrongly treating some non-I2C device as an i2c_adapter.
1091  */
1092 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1093 {
1094         return (dev->type == &i2c_adapter_type)
1095                         ? to_i2c_adapter(dev)
1096                         : NULL;
1097 }
1098 EXPORT_SYMBOL(i2c_verify_adapter);
1099
1100 #ifdef CONFIG_I2C_COMPAT
1101 static struct class_compat *i2c_adapter_compat_class;
1102 #endif
1103
1104 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1105 {
1106         struct i2c_devinfo      *devinfo;
1107
1108         down_read(&__i2c_board_lock);
1109         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1110                 if (devinfo->busnum == adapter->nr
1111                                 && !i2c_new_device(adapter,
1112                                                 &devinfo->board_info))
1113                         dev_err(&adapter->dev,
1114                                 "Can't create device at 0x%02x\n",
1115                                 devinfo->board_info.addr);
1116         }
1117         up_read(&__i2c_board_lock);
1118 }
1119
1120 static int i2c_do_add_adapter(struct i2c_driver *driver,
1121                               struct i2c_adapter *adap)
1122 {
1123         /* Detect supported devices on that bus, and instantiate them */
1124         i2c_detect(adap, driver);
1125
1126         return 0;
1127 }
1128
1129 static int __process_new_adapter(struct device_driver *d, void *data)
1130 {
1131         return i2c_do_add_adapter(to_i2c_driver(d), data);
1132 }
1133
1134 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1135         .lock_bus =    i2c_adapter_lock_bus,
1136         .trylock_bus = i2c_adapter_trylock_bus,
1137         .unlock_bus =  i2c_adapter_unlock_bus,
1138 };
1139
1140 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1141 {
1142         struct irq_domain *domain = adap->host_notify_domain;
1143         irq_hw_number_t hwirq;
1144
1145         if (!domain)
1146                 return;
1147
1148         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1149                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1150
1151         irq_domain_remove(domain);
1152         adap->host_notify_domain = NULL;
1153 }
1154
1155 static int i2c_host_notify_irq_map(struct irq_domain *h,
1156                                           unsigned int virq,
1157                                           irq_hw_number_t hw_irq_num)
1158 {
1159         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1160
1161         return 0;
1162 }
1163
1164 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1165         .map = i2c_host_notify_irq_map,
1166 };
1167
1168 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1169 {
1170         struct irq_domain *domain;
1171
1172         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1173                 return 0;
1174
1175         domain = irq_domain_create_linear(adap->dev.fwnode,
1176                                           I2C_ADDR_7BITS_COUNT,
1177                                           &i2c_host_notify_irq_ops, adap);
1178         if (!domain)
1179                 return -ENOMEM;
1180
1181         adap->host_notify_domain = domain;
1182
1183         return 0;
1184 }
1185
1186 /**
1187  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1188  * I2C client.
1189  * @adap: the adapter
1190  * @addr: the I2C address of the notifying device
1191  * Context: can't sleep
1192  *
1193  * Helper function to be called from an I2C bus driver's interrupt
1194  * handler. It will schedule the Host Notify IRQ.
1195  */
1196 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1197 {
1198         int irq;
1199
1200         if (!adap)
1201                 return -EINVAL;
1202
1203         irq = irq_find_mapping(adap->host_notify_domain, addr);
1204         if (irq <= 0)
1205                 return -ENXIO;
1206
1207         generic_handle_irq(irq);
1208
1209         return 0;
1210 }
1211 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1212
1213 static int i2c_register_adapter(struct i2c_adapter *adap)
1214 {
1215         int res = -EINVAL;
1216
1217         /* Can't register until after driver model init */
1218         if (WARN_ON(!is_registered)) {
1219                 res = -EAGAIN;
1220                 goto out_list;
1221         }
1222
1223         /* Sanity checks */
1224         if (WARN(!adap->name[0], "i2c adapter has no name"))
1225                 goto out_list;
1226
1227         if (!adap->algo) {
1228                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1229                 goto out_list;
1230         }
1231
1232         if (!adap->lock_ops)
1233                 adap->lock_ops = &i2c_adapter_lock_ops;
1234
1235         rt_mutex_init(&adap->bus_lock);
1236         rt_mutex_init(&adap->mux_lock);
1237         mutex_init(&adap->userspace_clients_lock);
1238         INIT_LIST_HEAD(&adap->userspace_clients);
1239
1240         /* Set default timeout to 1 second if not already set */
1241         if (adap->timeout == 0)
1242                 adap->timeout = HZ;
1243
1244         /* register soft irqs for Host Notify */
1245         res = i2c_setup_host_notify_irq_domain(adap);
1246         if (res) {
1247                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1248                        adap->name, res);
1249                 goto out_list;
1250         }
1251
1252         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1253         adap->dev.bus = &i2c_bus_type;
1254         adap->dev.type = &i2c_adapter_type;
1255         res = device_register(&adap->dev);
1256         if (res) {
1257                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1258                 goto out_list;
1259         }
1260
1261         res = of_i2c_setup_smbus_alert(adap);
1262         if (res)
1263                 goto out_reg;
1264
1265         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1266
1267         pm_runtime_no_callbacks(&adap->dev);
1268         pm_suspend_ignore_children(&adap->dev, true);
1269         pm_runtime_enable(&adap->dev);
1270
1271 #ifdef CONFIG_I2C_COMPAT
1272         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1273                                        adap->dev.parent);
1274         if (res)
1275                 dev_warn(&adap->dev,
1276                          "Failed to create compatibility class link\n");
1277 #endif
1278
1279         i2c_init_recovery(adap);
1280
1281         /* create pre-declared device nodes */
1282         of_i2c_register_devices(adap);
1283         i2c_acpi_register_devices(adap);
1284         i2c_acpi_install_space_handler(adap);
1285
1286         if (adap->nr < __i2c_first_dynamic_bus_num)
1287                 i2c_scan_static_board_info(adap);
1288
1289         /* Notify drivers */
1290         mutex_lock(&core_lock);
1291         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1292         mutex_unlock(&core_lock);
1293
1294         return 0;
1295
1296 out_reg:
1297         init_completion(&adap->dev_released);
1298         device_unregister(&adap->dev);
1299         wait_for_completion(&adap->dev_released);
1300 out_list:
1301         mutex_lock(&core_lock);
1302         idr_remove(&i2c_adapter_idr, adap->nr);
1303         mutex_unlock(&core_lock);
1304         return res;
1305 }
1306
1307 /**
1308  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1309  * @adap: the adapter to register (with adap->nr initialized)
1310  * Context: can sleep
1311  *
1312  * See i2c_add_numbered_adapter() for details.
1313  */
1314 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1315 {
1316         int id;
1317
1318         mutex_lock(&core_lock);
1319         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1320         mutex_unlock(&core_lock);
1321         if (WARN(id < 0, "couldn't get idr"))
1322                 return id == -ENOSPC ? -EBUSY : id;
1323
1324         return i2c_register_adapter(adap);
1325 }
1326
1327 /**
1328  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1329  * @adapter: the adapter to add
1330  * Context: can sleep
1331  *
1332  * This routine is used to declare an I2C adapter when its bus number
1333  * doesn't matter or when its bus number is specified by an dt alias.
1334  * Examples of bases when the bus number doesn't matter: I2C adapters
1335  * dynamically added by USB links or PCI plugin cards.
1336  *
1337  * When this returns zero, a new bus number was allocated and stored
1338  * in adap->nr, and the specified adapter became available for clients.
1339  * Otherwise, a negative errno value is returned.
1340  */
1341 int i2c_add_adapter(struct i2c_adapter *adapter)
1342 {
1343         struct device *dev = &adapter->dev;
1344         int id;
1345
1346         if (dev->of_node) {
1347                 id = of_alias_get_id(dev->of_node, "i2c");
1348                 if (id >= 0) {
1349                         adapter->nr = id;
1350                         return __i2c_add_numbered_adapter(adapter);
1351                 }
1352         }
1353
1354         mutex_lock(&core_lock);
1355         id = idr_alloc(&i2c_adapter_idr, adapter,
1356                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1357         mutex_unlock(&core_lock);
1358         if (WARN(id < 0, "couldn't get idr"))
1359                 return id;
1360
1361         adapter->nr = id;
1362
1363         return i2c_register_adapter(adapter);
1364 }
1365 EXPORT_SYMBOL(i2c_add_adapter);
1366
1367 /**
1368  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1369  * @adap: the adapter to register (with adap->nr initialized)
1370  * Context: can sleep
1371  *
1372  * This routine is used to declare an I2C adapter when its bus number
1373  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1374  * or otherwise built in to the system's mainboard, and where i2c_board_info
1375  * is used to properly configure I2C devices.
1376  *
1377  * If the requested bus number is set to -1, then this function will behave
1378  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1379  *
1380  * If no devices have pre-been declared for this bus, then be sure to
1381  * register the adapter before any dynamically allocated ones.  Otherwise
1382  * the required bus ID may not be available.
1383  *
1384  * When this returns zero, the specified adapter became available for
1385  * clients using the bus number provided in adap->nr.  Also, the table
1386  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1387  * and the appropriate driver model device nodes are created.  Otherwise, a
1388  * negative errno value is returned.
1389  */
1390 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1391 {
1392         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1393                 return i2c_add_adapter(adap);
1394
1395         return __i2c_add_numbered_adapter(adap);
1396 }
1397 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1398
1399 static void i2c_do_del_adapter(struct i2c_driver *driver,
1400                               struct i2c_adapter *adapter)
1401 {
1402         struct i2c_client *client, *_n;
1403
1404         /* Remove the devices we created ourselves as the result of hardware
1405          * probing (using a driver's detect method) */
1406         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1407                 if (client->adapter == adapter) {
1408                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1409                                 client->name, client->addr);
1410                         list_del(&client->detected);
1411                         i2c_unregister_device(client);
1412                 }
1413         }
1414 }
1415
1416 static int __unregister_client(struct device *dev, void *dummy)
1417 {
1418         struct i2c_client *client = i2c_verify_client(dev);
1419         if (client && strcmp(client->name, "dummy"))
1420                 i2c_unregister_device(client);
1421         return 0;
1422 }
1423
1424 static int __unregister_dummy(struct device *dev, void *dummy)
1425 {
1426         struct i2c_client *client = i2c_verify_client(dev);
1427         i2c_unregister_device(client);
1428         return 0;
1429 }
1430
1431 static int __process_removed_adapter(struct device_driver *d, void *data)
1432 {
1433         i2c_do_del_adapter(to_i2c_driver(d), data);
1434         return 0;
1435 }
1436
1437 /**
1438  * i2c_del_adapter - unregister I2C adapter
1439  * @adap: the adapter being unregistered
1440  * Context: can sleep
1441  *
1442  * This unregisters an I2C adapter which was previously registered
1443  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1444  */
1445 void i2c_del_adapter(struct i2c_adapter *adap)
1446 {
1447         struct i2c_adapter *found;
1448         struct i2c_client *client, *next;
1449
1450         /* First make sure that this adapter was ever added */
1451         mutex_lock(&core_lock);
1452         found = idr_find(&i2c_adapter_idr, adap->nr);
1453         mutex_unlock(&core_lock);
1454         if (found != adap) {
1455                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1456                 return;
1457         }
1458
1459         i2c_acpi_remove_space_handler(adap);
1460         /* Tell drivers about this removal */
1461         mutex_lock(&core_lock);
1462         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1463                                __process_removed_adapter);
1464         mutex_unlock(&core_lock);
1465
1466         /* Remove devices instantiated from sysfs */
1467         mutex_lock_nested(&adap->userspace_clients_lock,
1468                           i2c_adapter_depth(adap));
1469         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1470                                  detected) {
1471                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1472                         client->addr);
1473                 list_del(&client->detected);
1474                 i2c_unregister_device(client);
1475         }
1476         mutex_unlock(&adap->userspace_clients_lock);
1477
1478         /* Detach any active clients. This can't fail, thus we do not
1479          * check the returned value. This is a two-pass process, because
1480          * we can't remove the dummy devices during the first pass: they
1481          * could have been instantiated by real devices wishing to clean
1482          * them up properly, so we give them a chance to do that first. */
1483         device_for_each_child(&adap->dev, NULL, __unregister_client);
1484         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1485
1486 #ifdef CONFIG_I2C_COMPAT
1487         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1488                                  adap->dev.parent);
1489 #endif
1490
1491         /* device name is gone after device_unregister */
1492         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1493
1494         pm_runtime_disable(&adap->dev);
1495
1496         i2c_host_notify_irq_teardown(adap);
1497
1498         /* wait until all references to the device are gone
1499          *
1500          * FIXME: This is old code and should ideally be replaced by an
1501          * alternative which results in decoupling the lifetime of the struct
1502          * device from the i2c_adapter, like spi or netdev do. Any solution
1503          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1504          */
1505         init_completion(&adap->dev_released);
1506         device_unregister(&adap->dev);
1507         wait_for_completion(&adap->dev_released);
1508
1509         /* free bus id */
1510         mutex_lock(&core_lock);
1511         idr_remove(&i2c_adapter_idr, adap->nr);
1512         mutex_unlock(&core_lock);
1513
1514         /* Clear the device structure in case this adapter is ever going to be
1515            added again */
1516         memset(&adap->dev, 0, sizeof(adap->dev));
1517 }
1518 EXPORT_SYMBOL(i2c_del_adapter);
1519
1520 /**
1521  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1522  * @dev: The device to scan for I2C timing properties
1523  * @t: the i2c_timings struct to be filled with values
1524  * @use_defaults: bool to use sane defaults derived from the I2C specification
1525  *                when properties are not found, otherwise use 0
1526  *
1527  * Scan the device for the generic I2C properties describing timing parameters
1528  * for the signal and fill the given struct with the results. If a property was
1529  * not found and use_defaults was true, then maximum timings are assumed which
1530  * are derived from the I2C specification. If use_defaults is not used, the
1531  * results will be 0, so drivers can apply their own defaults later. The latter
1532  * is mainly intended for avoiding regressions of existing drivers which want
1533  * to switch to this function. New drivers almost always should use the defaults.
1534  */
1535
1536 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1537 {
1538         int ret;
1539
1540         memset(t, 0, sizeof(*t));
1541
1542         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1543         if (ret && use_defaults)
1544                 t->bus_freq_hz = 100000;
1545
1546         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1547         if (ret && use_defaults) {
1548                 if (t->bus_freq_hz <= 100000)
1549                         t->scl_rise_ns = 1000;
1550                 else if (t->bus_freq_hz <= 400000)
1551                         t->scl_rise_ns = 300;
1552                 else
1553                         t->scl_rise_ns = 120;
1554         }
1555
1556         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1557         if (ret && use_defaults) {
1558                 if (t->bus_freq_hz <= 400000)
1559                         t->scl_fall_ns = 300;
1560                 else
1561                         t->scl_fall_ns = 120;
1562         }
1563
1564         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1565
1566         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1567         if (ret && use_defaults)
1568                 t->sda_fall_ns = t->scl_fall_ns;
1569
1570         device_property_read_u32(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns);
1571 }
1572 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1573
1574 /* ------------------------------------------------------------------------- */
1575
1576 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1577 {
1578         int res;
1579
1580         mutex_lock(&core_lock);
1581         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1582         mutex_unlock(&core_lock);
1583
1584         return res;
1585 }
1586 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1587
1588 static int __process_new_driver(struct device *dev, void *data)
1589 {
1590         if (dev->type != &i2c_adapter_type)
1591                 return 0;
1592         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1593 }
1594
1595 /*
1596  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1597  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1598  */
1599
1600 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1601 {
1602         int res;
1603
1604         /* Can't register until after driver model init */
1605         if (WARN_ON(!is_registered))
1606                 return -EAGAIN;
1607
1608         /* add the driver to the list of i2c drivers in the driver core */
1609         driver->driver.owner = owner;
1610         driver->driver.bus = &i2c_bus_type;
1611         INIT_LIST_HEAD(&driver->clients);
1612
1613         /* When registration returns, the driver core
1614          * will have called probe() for all matching-but-unbound devices.
1615          */
1616         res = driver_register(&driver->driver);
1617         if (res)
1618                 return res;
1619
1620         pr_debug("driver [%s] registered\n", driver->driver.name);
1621
1622         /* Walk the adapters that are already present */
1623         i2c_for_each_dev(driver, __process_new_driver);
1624
1625         return 0;
1626 }
1627 EXPORT_SYMBOL(i2c_register_driver);
1628
1629 static int __process_removed_driver(struct device *dev, void *data)
1630 {
1631         if (dev->type == &i2c_adapter_type)
1632                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1633         return 0;
1634 }
1635
1636 /**
1637  * i2c_del_driver - unregister I2C driver
1638  * @driver: the driver being unregistered
1639  * Context: can sleep
1640  */
1641 void i2c_del_driver(struct i2c_driver *driver)
1642 {
1643         i2c_for_each_dev(driver, __process_removed_driver);
1644
1645         driver_unregister(&driver->driver);
1646         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1647 }
1648 EXPORT_SYMBOL(i2c_del_driver);
1649
1650 /* ------------------------------------------------------------------------- */
1651
1652 /**
1653  * i2c_use_client - increments the reference count of the i2c client structure
1654  * @client: the client being referenced
1655  *
1656  * Each live reference to a client should be refcounted. The driver model does
1657  * that automatically as part of driver binding, so that most drivers don't
1658  * need to do this explicitly: they hold a reference until they're unbound
1659  * from the device.
1660  *
1661  * A pointer to the client with the incremented reference counter is returned.
1662  */
1663 struct i2c_client *i2c_use_client(struct i2c_client *client)
1664 {
1665         if (client && get_device(&client->dev))
1666                 return client;
1667         return NULL;
1668 }
1669 EXPORT_SYMBOL(i2c_use_client);
1670
1671 /**
1672  * i2c_release_client - release a use of the i2c client structure
1673  * @client: the client being no longer referenced
1674  *
1675  * Must be called when a user of a client is finished with it.
1676  */
1677 void i2c_release_client(struct i2c_client *client)
1678 {
1679         if (client)
1680                 put_device(&client->dev);
1681 }
1682 EXPORT_SYMBOL(i2c_release_client);
1683
1684 struct i2c_cmd_arg {
1685         unsigned        cmd;
1686         void            *arg;
1687 };
1688
1689 static int i2c_cmd(struct device *dev, void *_arg)
1690 {
1691         struct i2c_client       *client = i2c_verify_client(dev);
1692         struct i2c_cmd_arg      *arg = _arg;
1693         struct i2c_driver       *driver;
1694
1695         if (!client || !client->dev.driver)
1696                 return 0;
1697
1698         driver = to_i2c_driver(client->dev.driver);
1699         if (driver->command)
1700                 driver->command(client, arg->cmd, arg->arg);
1701         return 0;
1702 }
1703
1704 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1705 {
1706         struct i2c_cmd_arg      cmd_arg;
1707
1708         cmd_arg.cmd = cmd;
1709         cmd_arg.arg = arg;
1710         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1711 }
1712 EXPORT_SYMBOL(i2c_clients_command);
1713
1714 static int __init i2c_init(void)
1715 {
1716         int retval;
1717
1718         retval = of_alias_get_highest_id("i2c");
1719
1720         down_write(&__i2c_board_lock);
1721         if (retval >= __i2c_first_dynamic_bus_num)
1722                 __i2c_first_dynamic_bus_num = retval + 1;
1723         up_write(&__i2c_board_lock);
1724
1725         retval = bus_register(&i2c_bus_type);
1726         if (retval)
1727                 return retval;
1728
1729         is_registered = true;
1730
1731 #ifdef CONFIG_I2C_COMPAT
1732         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1733         if (!i2c_adapter_compat_class) {
1734                 retval = -ENOMEM;
1735                 goto bus_err;
1736         }
1737 #endif
1738         retval = i2c_add_driver(&dummy_driver);
1739         if (retval)
1740                 goto class_err;
1741
1742         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1743                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1744         if (IS_ENABLED(CONFIG_ACPI))
1745                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1746
1747         return 0;
1748
1749 class_err:
1750 #ifdef CONFIG_I2C_COMPAT
1751         class_compat_unregister(i2c_adapter_compat_class);
1752 bus_err:
1753 #endif
1754         is_registered = false;
1755         bus_unregister(&i2c_bus_type);
1756         return retval;
1757 }
1758
1759 static void __exit i2c_exit(void)
1760 {
1761         if (IS_ENABLED(CONFIG_ACPI))
1762                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1763         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1764                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1765         i2c_del_driver(&dummy_driver);
1766 #ifdef CONFIG_I2C_COMPAT
1767         class_compat_unregister(i2c_adapter_compat_class);
1768 #endif
1769         bus_unregister(&i2c_bus_type);
1770         tracepoint_synchronize_unregister();
1771 }
1772
1773 /* We must initialize early, because some subsystems register i2c drivers
1774  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1775  */
1776 postcore_initcall(i2c_init);
1777 module_exit(i2c_exit);
1778
1779 /* ----------------------------------------------------
1780  * the functional interface to the i2c busses.
1781  * ----------------------------------------------------
1782  */
1783
1784 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1785 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1786
1787 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1788 {
1789         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1790                             err_msg, msg->addr, msg->len,
1791                             msg->flags & I2C_M_RD ? "read" : "write");
1792         return -EOPNOTSUPP;
1793 }
1794
1795 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1796 {
1797         const struct i2c_adapter_quirks *q = adap->quirks;
1798         int max_num = q->max_num_msgs, i;
1799         bool do_len_check = true;
1800
1801         if (q->flags & I2C_AQ_COMB) {
1802                 max_num = 2;
1803
1804                 /* special checks for combined messages */
1805                 if (num == 2) {
1806                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1807                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1808
1809                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1810                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1811
1812                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1813                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1814
1815                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1816                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1817
1818                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1819                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1820
1821                         do_len_check = false;
1822                 }
1823         }
1824
1825         if (i2c_quirk_exceeded(num, max_num))
1826                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1827
1828         for (i = 0; i < num; i++) {
1829                 u16 len = msgs[i].len;
1830
1831                 if (msgs[i].flags & I2C_M_RD) {
1832                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1833                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1834
1835                         if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
1836                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1837                 } else {
1838                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1839                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1840
1841                         if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
1842                                 return i2c_quirk_error(adap, &msgs[i], "no zero length");
1843                 }
1844         }
1845
1846         return 0;
1847 }
1848
1849 /**
1850  * __i2c_transfer - unlocked flavor of i2c_transfer
1851  * @adap: Handle to I2C bus
1852  * @msgs: One or more messages to execute before STOP is issued to
1853  *      terminate the operation; each message begins with a START.
1854  * @num: Number of messages to be executed.
1855  *
1856  * Returns negative errno, else the number of messages executed.
1857  *
1858  * Adapter lock must be held when calling this function. No debug logging
1859  * takes place. adap->algo->master_xfer existence isn't checked.
1860  */
1861 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1862 {
1863         unsigned long orig_jiffies;
1864         int ret, try;
1865
1866         if (WARN_ON(!msgs || num < 1))
1867                 return -EINVAL;
1868
1869         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1870                 return -EOPNOTSUPP;
1871
1872         /*
1873          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1874          * enabled.  This is an efficient way of keeping the for-loop from
1875          * being executed when not needed.
1876          */
1877         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1878                 int i;
1879                 for (i = 0; i < num; i++)
1880                         if (msgs[i].flags & I2C_M_RD)
1881                                 trace_i2c_read(adap, &msgs[i], i);
1882                         else
1883                                 trace_i2c_write(adap, &msgs[i], i);
1884         }
1885
1886         /* Retry automatically on arbitration loss */
1887         orig_jiffies = jiffies;
1888         for (ret = 0, try = 0; try <= adap->retries; try++) {
1889                 ret = adap->algo->master_xfer(adap, msgs, num);
1890                 if (ret != -EAGAIN)
1891                         break;
1892                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1893                         break;
1894         }
1895
1896         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1897                 int i;
1898                 for (i = 0; i < ret; i++)
1899                         if (msgs[i].flags & I2C_M_RD)
1900                                 trace_i2c_reply(adap, &msgs[i], i);
1901                 trace_i2c_result(adap, num, ret);
1902         }
1903
1904         return ret;
1905 }
1906 EXPORT_SYMBOL(__i2c_transfer);
1907
1908 /**
1909  * i2c_transfer - execute a single or combined I2C message
1910  * @adap: Handle to I2C bus
1911  * @msgs: One or more messages to execute before STOP is issued to
1912  *      terminate the operation; each message begins with a START.
1913  * @num: Number of messages to be executed.
1914  *
1915  * Returns negative errno, else the number of messages executed.
1916  *
1917  * Note that there is no requirement that each message be sent to
1918  * the same slave address, although that is the most common model.
1919  */
1920 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1921 {
1922         int ret;
1923
1924         if (!adap->algo->master_xfer) {
1925                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1926                 return -EOPNOTSUPP;
1927         }
1928
1929         /* REVISIT the fault reporting model here is weak:
1930          *
1931          *  - When we get an error after receiving N bytes from a slave,
1932          *    there is no way to report "N".
1933          *
1934          *  - When we get a NAK after transmitting N bytes to a slave,
1935          *    there is no way to report "N" ... or to let the master
1936          *    continue executing the rest of this combined message, if
1937          *    that's the appropriate response.
1938          *
1939          *  - When for example "num" is two and we successfully complete
1940          *    the first message but get an error part way through the
1941          *    second, it's unclear whether that should be reported as
1942          *    one (discarding status on the second message) or errno
1943          *    (discarding status on the first one).
1944          */
1945         if (in_atomic() || irqs_disabled()) {
1946                 ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1947                 if (!ret)
1948                         /* I2C activity is ongoing. */
1949                         return -EAGAIN;
1950         } else {
1951                 i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1952         }
1953
1954         ret = __i2c_transfer(adap, msgs, num);
1955         i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1956
1957         return ret;
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_put_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_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2285  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2286  * @msg: the message which the buffer corresponds to
2287  * @xferred: bool saying if the message was transferred
2288  */
2289 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2290 {
2291         if (!buf || buf == msg->buf)
2292                 return;
2293
2294         if (xferred && msg->flags & I2C_M_RD)
2295                 memcpy(msg->buf, buf, msg->len);
2296
2297         kfree(buf);
2298 }
2299 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2300
2301 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2302 MODULE_DESCRIPTION("I2C-Bus main module");
2303 MODULE_LICENSE("GPL");