drivers/i2c/i2c-core-base.c

   1 /*
   2  * Linux I2C core
   3  *
   4  * Copyright (C) 1995-99 Simon G. Vogl
   5  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   6  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   7  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   8  *
   9  * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  19  */
  20
  21 #define pr_fmt(fmt) "i2c-core: " fmt
  22
  23 #include <dt-bindings/i2c/i2c.h>
  24 #include <linux/acpi.h>
  25 #include <linux/clk/clk-conf.h>
  26 #include <linux/completion.h>
  27 #include <linux/delay.h>
  28 #include <linux/err.h>
  29 #include <linux/errno.h>
  30 #include <linux/gpio.h>
  31 #include <linux/i2c.h>
  32 #include <linux/idr.h>
  33 #include <linux/init.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/irqflags.h>
  36 #include <linux/jump_label.h>
  37 #include <linux/kernel.h>
  38 #include <linux/module.h>
  39 #include <linux/mutex.h>
  40 #include <linux/of_device.h>
  41 #include <linux/of.h>
  42 #include <linux/of_irq.h>
  43 #include <linux/pm_domain.h>
  44 #include <linux/pm_runtime.h>
  45 #include <linux/pm_wakeirq.h>
  46 #include <linux/property.h>
  47 #include <linux/rwsem.h>
  48 #include <linux/slab.h>
  49
  50 #include "i2c-core.h"
  51
  52 #define CREATE_TRACE_POINTS
  53 #include <trace/events/i2c.h>
  54
  55 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
  56 #define I2C_ADDR_OFFSET_SLAVE   0x1000
  57
  58 #define I2C_ADDR_7BITS_MAX      0x77
  59 #define I2C_ADDR_7BITS_COUNT    (I2C_ADDR_7BITS_MAX + 1)
  60
  61 /*
  62  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  63  * deletion of detected devices, and attach_adapter calls are serialized
  64  */
  65 static DEFINE_MUTEX(core_lock);
  66 static DEFINE_IDR(i2c_adapter_idr);
  67
  68 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  69
  70 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
  71 static bool is_registered;
  72
  73 int i2c_transfer_trace_reg(void)
  74 {
  75         static_key_slow_inc(&i2c_trace_msg);
  76         return 0;
  77 }
  78
  79 void i2c_transfer_trace_unreg(void)
  80 {
  81         static_key_slow_dec(&i2c_trace_msg);
  82 }
  83
  84 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  85                                                 const struct i2c_client *client)
  86 {
  87         if (!(id && client))
  88                 return NULL;
  89
  90         while (id->name[0]) {
  91                 if (strcmp(client->name, id->name) == 0)
  92                         return id;
  93                 id++;
  94         }
  95         return NULL;
  96 }
  97 EXPORT_SYMBOL_GPL(i2c_match_id);
  98
  99 static int i2c_device_match(struct device *dev, struct device_driver *drv)
 100 {
 101         struct i2c_client       *client = i2c_verify_client(dev);
 102         struct i2c_driver       *driver;
 103
 104
 105         /* Attempt an OF style match */
 106         if (i2c_of_match_device(drv->of_match_table, client))
 107                 return 1;
 108
 109         /* Then ACPI style match */
 110         if (acpi_driver_match_device(dev, drv))
 111                 return 1;
 112
 113         driver = to_i2c_driver(drv);
 114
 115         /* Finally an I2C match */
 116         if (i2c_match_id(driver->id_table, client))
 117                 return 1;
 118
 119         return 0;
 120 }
 121
 122 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 123 {
 124         struct i2c_client *client = to_i2c_client(dev);
 125         int rc;
 126
 127         rc = acpi_device_uevent_modalias(dev, env);
 128         if (rc != -ENODEV)
 129                 return rc;
 130
 131         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 132 }
 133
 134 /* i2c bus recovery routines */
 135 static int get_scl_gpio_value(struct i2c_adapter *adap)
 136 {
 137         return gpio_get_value(adap->bus_recovery_info->scl_gpio);
 138 }
 139
 140 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 141 {
 142         gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
 143 }
 144
 145 static int get_sda_gpio_value(struct i2c_adapter *adap)
 146 {
 147         return gpio_get_value(adap->bus_recovery_info->sda_gpio);
 148 }
 149
 150 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
 151 {
 152         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 153         struct device *dev = &adap->dev;
 154         int ret = 0;
 155
 156         ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
 157                         GPIOF_OUT_INIT_HIGH, "i2c-scl");
 158         if (ret) {
 159                 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
 160                 return ret;
 161         }
 162
 163         if (bri->get_sda) {
 164                 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
 165                         /* work without SDA polling */
 166                         dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
 167                                         bri->sda_gpio);
 168                         bri->get_sda = NULL;
 169                 }
 170         }
 171
 172         return ret;
 173 }
 174
 175 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
 176 {
 177         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 178
 179         if (bri->get_sda)
 180                 gpio_free(bri->sda_gpio);
 181
 182         gpio_free(bri->scl_gpio);
 183 }
 184
 185 /*
 186  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 187  * We will generate clock with rate 100 KHz and so duration of both clock levels
 188  * is: delay in ns = (10^6 / 100) / 2
 189  */
 190 #define RECOVERY_NDELAY         5000
 191 #define RECOVERY_CLK_CNT        9
 192
 193 static int i2c_generic_recovery(struct i2c_adapter *adap)
 194 {
 195         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 196         int i = 0, val = 1, ret = 0;
 197
 198         if (bri->prepare_recovery)
 199                 bri->prepare_recovery(adap);
 200
 201         bri->set_scl(adap, val);
 202         ndelay(RECOVERY_NDELAY);
 203
 204         /*
 205          * By this time SCL is high, as we need to give 9 falling-rising edges
 206          */
 207         while (i++ < RECOVERY_CLK_CNT * 2) {
 208                 if (val) {
 209                         /* Break if SDA is high */
 210                         if (bri->get_sda && bri->get_sda(adap))
 211                                         break;
 212                         /* SCL shouldn't be low here */
 213                         if (!bri->get_scl(adap)) {
 214                                 dev_err(&adap->dev,
 215                                         "SCL is stuck low, exit recovery\n");
 216                                 ret = -EBUSY;
 217                                 break;
 218                         }
 219                 }
 220
 221                 val = !val;
 222                 bri->set_scl(adap, val);
 223                 ndelay(RECOVERY_NDELAY);
 224         }
 225
 226         if (bri->unprepare_recovery)
 227                 bri->unprepare_recovery(adap);
 228
 229         return ret;
 230 }
 231
 232 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 233 {
 234         return i2c_generic_recovery(adap);
 235 }
 236 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 237
 238 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
 239 {
 240         int ret;
 241
 242         ret = i2c_get_gpios_for_recovery(adap);
 243         if (ret)
 244                 return ret;
 245
 246         ret = i2c_generic_recovery(adap);
 247         i2c_put_gpios_for_recovery(adap);
 248
 249         return ret;
 250 }
 251 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
 252
 253 int i2c_recover_bus(struct i2c_adapter *adap)
 254 {
 255         if (!adap->bus_recovery_info)
 256                 return -EOPNOTSUPP;
 257
 258         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 259         return adap->bus_recovery_info->recover_bus(adap);
 260 }
 261 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 262
 263 static void i2c_init_recovery(struct i2c_adapter *adap)
 264 {
 265         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 266         char *err_str, *err_level = KERN_ERR;
 267
 268         if (!bri)
 269                 return;
 270
 271         if (!bri->recover_bus) {
 272                 err_str = "no suitable method provided";
 273                 err_level = KERN_DEBUG;
 274                 goto err;
 275         }
 276
 277         /* Generic GPIO recovery */
 278         if (bri->recover_bus == i2c_generic_gpio_recovery) {
 279                 if (!gpio_is_valid(bri->scl_gpio)) {
 280                         err_str = "invalid SCL gpio";
 281                         goto err;
 282                 }
 283
 284                 if (gpio_is_valid(bri->sda_gpio))
 285                         bri->get_sda = get_sda_gpio_value;
 286                 else
 287                         bri->get_sda = NULL;
 288
 289                 bri->get_scl = get_scl_gpio_value;
 290                 bri->set_scl = set_scl_gpio_value;
 291         } else if (bri->recover_bus == i2c_generic_scl_recovery) {
 292                 /* Generic SCL recovery */
 293                 if (!bri->set_scl || !bri->get_scl) {
 294                         err_str = "no {get|set}_scl() found";
 295                         goto err;
 296                 }
 297         }
 298
 299         return;
 300  err:
 301         dev_printk(err_level, &adap->dev, "Not using recovery: %s\n", err_str);
 302         adap->bus_recovery_info = NULL;
 303 }
 304
 305 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 306 {
 307         struct i2c_adapter *adap = client->adapter;
 308         unsigned int irq;
 309
 310         if (!adap->host_notify_domain)
 311                 return -ENXIO;
 312
 313         if (client->flags & I2C_CLIENT_TEN)
 314                 return -EINVAL;
 315
 316         irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 317         if (!irq)
 318                 irq = irq_create_mapping(adap->host_notify_domain,
 319                                          client->addr);
 320
 321         return irq > 0 ? irq : -ENXIO;
 322 }
 323
 324 static int i2c_device_probe(struct device *dev)
 325 {
 326         struct i2c_client       *client = i2c_verify_client(dev);
 327         struct i2c_driver       *driver;
 328         int status;
 329
 330         if (!client)
 331                 return 0;
 332
 333         driver = to_i2c_driver(dev->driver);
 334
 335         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 336                 int irq = -ENOENT;
 337
 338                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 339                         dev_dbg(dev, "Using Host Notify IRQ\n");
 340                         irq = i2c_smbus_host_notify_to_irq(client);
 341                 } else if (dev->of_node) {
 342                         irq = of_irq_get_byname(dev->of_node, "irq");
 343                         if (irq == -EINVAL || irq == -ENODATA)
 344                                 irq = of_irq_get(dev->of_node, 0);
 345                 } else if (ACPI_COMPANION(dev)) {
 346                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 347                 }
 348                 if (irq == -EPROBE_DEFER)
 349                         return irq;
 350
 351                 if (irq < 0)
 352                         irq = 0;
 353
 354                 client->irq = irq;
 355         }
 356
 357         /*
 358          * An I2C ID table is not mandatory, if and only if, a suitable OF
 359          * or ACPI ID table is supplied for the probing device.
 360          */
 361         if (!driver->id_table &&
 362             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 363             !i2c_of_match_device(dev->driver->of_match_table, client))
 364                 return -ENODEV;
 365
 366         if (client->flags & I2C_CLIENT_WAKE) {
 367                 int wakeirq = -ENOENT;
 368
 369                 if (dev->of_node) {
 370                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 371                         if (wakeirq == -EPROBE_DEFER)
 372                                 return wakeirq;
 373                 }
 374
 375                 device_init_wakeup(&client->dev, true);
 376
 377                 if (wakeirq > 0 && wakeirq != client->irq)
 378                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 379                 else if (client->irq > 0)
 380                         status = dev_pm_set_wake_irq(dev, client->irq);
 381                 else
 382                         status = 0;
 383
 384                 if (status)
 385                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 386         }
 387
 388         dev_dbg(dev, "probe\n");
 389
 390         status = of_clk_set_defaults(dev->of_node, false);
 391         if (status < 0)
 392                 goto err_clear_wakeup_irq;
 393
 394         status = dev_pm_domain_attach(&client->dev, true);
 395         if (status == -EPROBE_DEFER)
 396                 goto err_clear_wakeup_irq;
 397
 398         /*
 399          * When there are no more users of probe(),
 400          * rename probe_new to probe.
 401          */
 402         if (driver->probe_new)
 403                 status = driver->probe_new(client);
 404         else if (driver->probe)
 405                 status = driver->probe(client,
 406                                        i2c_match_id(driver->id_table, client));
 407         else
 408                 status = -EINVAL;
 409
 410         if (status)
 411                 goto err_detach_pm_domain;
 412
 413         return 0;
 414
 415 err_detach_pm_domain:
 416         dev_pm_domain_detach(&client->dev, true);
 417 err_clear_wakeup_irq:
 418         dev_pm_clear_wake_irq(&client->dev);
 419         device_init_wakeup(&client->dev, false);
 420         return status;
 421 }
 422
 423 static int i2c_device_remove(struct device *dev)
 424 {
 425         struct i2c_client       *client = i2c_verify_client(dev);
 426         struct i2c_driver       *driver;
 427         int status = 0;
 428
 429         if (!client || !dev->driver)
 430                 return 0;
 431
 432         driver = to_i2c_driver(dev->driver);
 433         if (driver->remove) {
 434                 dev_dbg(dev, "remove\n");
 435                 status = driver->remove(client);
 436         }
 437
 438         dev_pm_domain_detach(&client->dev, true);
 439
 440         dev_pm_clear_wake_irq(&client->dev);
 441         device_init_wakeup(&client->dev, false);
 442
 443         return status;
 444 }
 445
 446 static void i2c_device_shutdown(struct device *dev)
 447 {
 448         struct i2c_client *client = i2c_verify_client(dev);
 449         struct i2c_driver *driver;
 450
 451         if (!client || !dev->driver)
 452                 return;
 453         driver = to_i2c_driver(dev->driver);
 454         if (driver->shutdown)
 455                 driver->shutdown(client);
 456         else if (client->irq > 0)
 457                 disable_irq(client->irq);
 458 }
 459
 460 static void i2c_client_dev_release(struct device *dev)
 461 {
 462         kfree(to_i2c_client(dev));
 463 }
 464
 465 static ssize_t
 466 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 467 {
 468         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 469                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 470 }
 471 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 472
 473 static ssize_t
 474 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 475 {
 476         struct i2c_client *client = to_i2c_client(dev);
 477         int len;
 478
 479         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 480         if (len != -ENODEV)
 481                 return len;
 482
 483         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 484 }
 485 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 486
 487 static struct attribute *i2c_dev_attrs[] = {
 488         &dev_attr_name.attr,
 489         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 490         &dev_attr_modalias.attr,
 491         NULL
 492 };
 493 ATTRIBUTE_GROUPS(i2c_dev);
 494
 495 struct bus_type i2c_bus_type = {
 496         .name           = "i2c",
 497         .match          = i2c_device_match,
 498         .probe          = i2c_device_probe,
 499         .remove         = i2c_device_remove,
 500         .shutdown       = i2c_device_shutdown,
 501 };
 502 EXPORT_SYMBOL_GPL(i2c_bus_type);
 503
 504 struct device_type i2c_client_type = {
 505         .groups         = i2c_dev_groups,
 506         .uevent         = i2c_device_uevent,
 507         .release        = i2c_client_dev_release,
 508 };
 509 EXPORT_SYMBOL_GPL(i2c_client_type);
 510
 511
 512 /**
 513  * i2c_verify_client - return parameter as i2c_client, or NULL
 514  * @dev: device, probably from some driver model iterator
 515  *
 516  * When traversing the driver model tree, perhaps using driver model
 517  * iterators like @device_for_each_child(), you can't assume very much
 518  * about the nodes you find.  Use this function to avoid oopses caused
 519  * by wrongly treating some non-I2C device as an i2c_client.
 520  */
 521 struct i2c_client *i2c_verify_client(struct device *dev)
 522 {
 523         return (dev->type == &i2c_client_type)
 524                         ? to_i2c_client(dev)
 525                         : NULL;
 526 }
 527 EXPORT_SYMBOL(i2c_verify_client);
 528
 529
 530 /* Return a unique address which takes the flags of the client into account */
 531 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 532 {
 533         unsigned short addr = client->addr;
 534
 535         /* For some client flags, add an arbitrary offset to avoid collisions */
 536         if (client->flags & I2C_CLIENT_TEN)
 537                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 538
 539         if (client->flags & I2C_CLIENT_SLAVE)
 540                 addr |= I2C_ADDR_OFFSET_SLAVE;
 541
 542         return addr;
 543 }
 544
 545 /* This is a permissive address validity check, I2C address map constraints
 546  * are purposely not enforced, except for the general call address. */
 547 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
 548 {
 549         if (flags & I2C_CLIENT_TEN) {
 550                 /* 10-bit address, all values are valid */
 551                 if (addr > 0x3ff)
 552                         return -EINVAL;
 553         } else {
 554                 /* 7-bit address, reject the general call address */
 555                 if (addr == 0x00 || addr > 0x7f)
 556                         return -EINVAL;
 557         }
 558         return 0;
 559 }
 560
 561 /* And this is a strict address validity check, used when probing. If a
 562  * device uses a reserved address, then it shouldn't be probed. 7-bit
 563  * addressing is assumed, 10-bit address devices are rare and should be
 564  * explicitly enumerated. */
 565 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 566 {
 567         /*
 568          * Reserved addresses per I2C specification:
 569          *  0x00       General call address / START byte
 570          *  0x01       CBUS address
 571          *  0x02       Reserved for different bus format
 572          *  0x03       Reserved for future purposes
 573          *  0x04-0x07  Hs-mode master code
 574          *  0x78-0x7b  10-bit slave addressing
 575          *  0x7c-0x7f  Reserved for future purposes
 576          */
 577         if (addr < 0x08 || addr > 0x77)
 578                 return -EINVAL;
 579         return 0;
 580 }
 581
 582 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 583 {
 584         struct i2c_client       *client = i2c_verify_client(dev);
 585         int                     addr = *(int *)addrp;
 586
 587         if (client && i2c_encode_flags_to_addr(client) == addr)
 588                 return -EBUSY;
 589         return 0;
 590 }
 591
 592 /* walk up mux tree */
 593 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 594 {
 595         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 596         int result;
 597
 598         result = device_for_each_child(&adapter->dev, &addr,
 599                                         __i2c_check_addr_busy);
 600
 601         if (!result && parent)
 602                 result = i2c_check_mux_parents(parent, addr);
 603
 604         return result;
 605 }
 606
 607 /* recurse down mux tree */
 608 static int i2c_check_mux_children(struct device *dev, void *addrp)
 609 {
 610         int result;
 611
 612         if (dev->type == &i2c_adapter_type)
 613                 result = device_for_each_child(dev, addrp,
 614                                                 i2c_check_mux_children);
 615         else
 616                 result = __i2c_check_addr_busy(dev, addrp);
 617
 618         return result;
 619 }
 620
 621 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 622 {
 623         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 624         int result = 0;
 625
 626         if (parent)
 627                 result = i2c_check_mux_parents(parent, addr);
 628
 629         if (!result)
 630                 result = device_for_each_child(&adapter->dev, &addr,
 631                                                 i2c_check_mux_children);
 632
 633         return result;
 634 }
 635
 636 /**
 637  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 638  * @adapter: Target I2C bus segment
 639  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 640  *      locks only this branch in the adapter tree
 641  */
 642 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 643                                  unsigned int flags)
 644 {
 645         rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 646 }
 647
 648 /**
 649  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 650  * @adapter: Target I2C bus segment
 651  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 652  *      trylocks only this branch in the adapter tree
 653  */
 654 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 655                                    unsigned int flags)
 656 {
 657         return rt_mutex_trylock(&adapter->bus_lock);
 658 }
 659
 660 /**
 661  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 662  * @adapter: Target I2C bus segment
 663  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 664  *      unlocks only this branch in the adapter tree
 665  */
 666 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 667                                    unsigned int flags)
 668 {
 669         rt_mutex_unlock(&adapter->bus_lock);
 670 }
 671
 672 static void i2c_dev_set_name(struct i2c_adapter *adap,
 673                              struct i2c_client *client)
 674 {
 675         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 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
 742         if (info->archdata)
 743                 client->dev.archdata = *info->archdata;
 744
 745         client->flags = info->flags;
 746         client->addr = info->addr;
 747
 748         client->irq = info->irq;
 749         if (!client->irq)
 750                 client->irq = i2c_dev_irq_from_resources(info->resources,
 751                                                          info->num_resources);
 752
 753         strlcpy(client->name, info->type, sizeof(client->name));
 754
 755         status = i2c_check_addr_validity(client->addr, client->flags);
 756         if (status) {
 757                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 758                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 759                 goto out_err_silent;
 760         }
 761
 762         /* Check for address business */
 763         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 764         if (status)
 765                 goto out_err;
 766
 767         client->dev.parent = &client->adapter->dev;
 768         client->dev.bus = &i2c_bus_type;
 769         client->dev.type = &i2c_client_type;
 770         client->dev.of_node = info->of_node;
 771         client->dev.fwnode = info->fwnode;
 772
 773         i2c_dev_set_name(adap, client);
 774
 775         if (info->properties) {
 776                 status = device_add_properties(&client->dev, info->properties);
 777                 if (status) {
 778                         dev_err(&adap->dev,
 779                                 "Failed to add properties to client %s: %d\n",
 780                                 client->name, status);
 781                         goto out_err;
 782                 }
 783         }
 784
 785         status = device_register(&client->dev);
 786         if (status)
 787                 goto out_free_props;
 788
 789         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 790                 client->name, dev_name(&client->dev));
 791
 792         return client;
 793
 794 out_free_props:
 795         if (info->properties)
 796                 device_remove_properties(&client->dev);
 797 out_err:
 798         dev_err(&adap->dev,
 799                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 800                 client->name, client->addr, status);
 801 out_err_silent:
 802         kfree(client);
 803         return NULL;
 804 }
 805 EXPORT_SYMBOL_GPL(i2c_new_device);
 806
 807
 808 /**
 809  * i2c_unregister_device - reverse effect of i2c_new_device()
 810  * @client: value returned from i2c_new_device()
 811  * Context: can sleep
 812  */
 813 void i2c_unregister_device(struct i2c_client *client)
 814 {
 815         if (client->dev.of_node) {
 816                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 817                 of_node_put(client->dev.of_node);
 818         }
 819
 820         if (ACPI_COMPANION(&client->dev))
 821                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 822         device_unregister(&client->dev);
 823 }
 824 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 825
 826
 827 static const struct i2c_device_id dummy_id[] = {
 828         { "dummy", 0 },
 829         { },
 830 };
 831
 832 static int dummy_probe(struct i2c_client *client,
 833                        const struct i2c_device_id *id)
 834 {
 835         return 0;
 836 }
 837
 838 static int dummy_remove(struct i2c_client *client)
 839 {
 840         return 0;
 841 }
 842
 843 static struct i2c_driver dummy_driver = {
 844         .driver.name    = "dummy",
 845         .probe          = dummy_probe,
 846         .remove         = dummy_remove,
 847         .id_table       = dummy_id,
 848 };
 849
 850 /**
 851  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 852  * @adapter: the adapter managing the device
 853  * @address: seven bit address to be used
 854  * Context: can sleep
 855  *
 856  * This returns an I2C client bound to the "dummy" driver, intended for use
 857  * with devices that consume multiple addresses.  Examples of such chips
 858  * include various EEPROMS (like 24c04 and 24c08 models).
 859  *
 860  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 861  * except i2c_transfer() need a client handle; the dummy will be that handle.
 862  * And second, this prevents the specified address from being bound to a
 863  * different driver.
 864  *
 865  * This returns the new i2c client, which should be saved for later use with
 866  * i2c_unregister_device(); or NULL to indicate an error.
 867  */
 868 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 869 {
 870         struct i2c_board_info info = {
 871                 I2C_BOARD_INFO("dummy", address),
 872         };
 873
 874         return i2c_new_device(adapter, &info);
 875 }
 876 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 877
 878 /**
 879  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 880  * and create the associated device
 881  * @client: Handle to the primary client
 882  * @name: Handle to specify which secondary address to get
 883  * @default_addr: Used as a fallback if no secondary address was specified
 884  * Context: can sleep
 885  *
 886  * I2C clients can be composed of multiple I2C slaves bound together in a single
 887  * component. The I2C client driver then binds to the master I2C slave and needs
 888  * to create I2C dummy clients to communicate with all the other slaves.
 889  *
 890  * This function creates and returns an I2C dummy client whose I2C address is
 891  * retrieved from the platform firmware based on the given slave name. If no
 892  * address is specified by the firmware default_addr is used.
 893  *
 894  * On DT-based platforms the address is retrieved from the "reg" property entry
 895  * cell whose "reg-names" value matches the slave name.
 896  *
 897  * This returns the new i2c client, which should be saved for later use with
 898  * i2c_unregister_device(); or NULL to indicate an error.
 899  */
 900 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 901                                                 const char *name,
 902                                                 u16 default_addr)
 903 {
 904         struct device_node *np = client->dev.of_node;
 905         u32 addr = default_addr;
 906         int i;
 907
 908         if (np) {
 909                 i = of_property_match_string(np, "reg-names", name);
 910                 if (i >= 0)
 911                         of_property_read_u32_index(np, "reg", i, &addr);
 912         }
 913
 914         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 915         return i2c_new_dummy(client->adapter, addr);
 916 }
 917 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 918
 919 /* ------------------------------------------------------------------------- */
 920
 921 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 922
 923 static void i2c_adapter_dev_release(struct device *dev)
 924 {
 925         struct i2c_adapter *adap = to_i2c_adapter(dev);
 926         complete(&adap->dev_released);
 927 }
 928
 929 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 930 {
 931         unsigned int depth = 0;
 932
 933         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 934                 depth++;
 935
 936         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 937                   "adapter depth exceeds lockdep subclass limit\n");
 938
 939         return depth;
 940 }
 941 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 942
 943 /*
 944  * Let users instantiate I2C devices through sysfs. This can be used when
 945  * platform initialization code doesn't contain the proper data for
 946  * whatever reason. Also useful for drivers that do device detection and
 947  * detection fails, either because the device uses an unexpected address,
 948  * or this is a compatible device with different ID register values.
 949  *
 950  * Parameter checking may look overzealous, but we really don't want
 951  * the user to provide incorrect parameters.
 952  */
 953 static ssize_t
 954 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 955                      const char *buf, size_t count)
 956 {
 957         struct i2c_adapter *adap = to_i2c_adapter(dev);
 958         struct i2c_board_info info;
 959         struct i2c_client *client;
 960         char *blank, end;
 961         int res;
 962
 963         memset(&info, 0, sizeof(struct i2c_board_info));
 964
 965         blank = strchr(buf, ' ');
 966         if (!blank) {
 967                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 968                 return -EINVAL;
 969         }
 970         if (blank - buf > I2C_NAME_SIZE - 1) {
 971                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 972                 return -EINVAL;
 973         }
 974         memcpy(info.type, buf, blank - buf);
 975
 976         /* Parse remaining parameters, reject extra parameters */
 977         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 978         if (res < 1) {
 979                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 980                 return -EINVAL;
 981         }
 982         if (res > 1  && end != '\n') {
 983                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 984                 return -EINVAL;
 985         }
 986
 987         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 988                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 989                 info.flags |= I2C_CLIENT_TEN;
 990         }
 991
 992         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 993                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 994                 info.flags |= I2C_CLIENT_SLAVE;
 995         }
 996
 997         client = i2c_new_device(adap, &info);
 998         if (!client)
 999                 return -EINVAL;
1000
1001         /* Keep track of the added device */
1002         mutex_lock(&adap->userspace_clients_lock);
1003         list_add_tail(&client->detected, &adap->userspace_clients);
1004         mutex_unlock(&adap->userspace_clients_lock);
1005         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1006                  info.type, info.addr);
1007
1008         return count;
1009 }
1010 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1011
1012 /*
1013  * And of course let the users delete the devices they instantiated, if
1014  * they got it wrong. This interface can only be used to delete devices
1015  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1016  * don't delete devices to which some kernel code still has references.
1017  *
1018  * Parameter checking may look overzealous, but we really don't want
1019  * the user to delete the wrong device.
1020  */
1021 static ssize_t
1022 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1023                         const char *buf, size_t count)
1024 {
1025         struct i2c_adapter *adap = to_i2c_adapter(dev);
1026         struct i2c_client *client, *next;
1027         unsigned short addr;
1028         char end;
1029         int res;
1030
1031         /* Parse parameters, reject extra parameters */
1032         res = sscanf(buf, "%hi%c", &addr, &end);
1033         if (res < 1) {
1034                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1035                 return -EINVAL;
1036         }
1037         if (res > 1  && end != '\n') {
1038                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1039                 return -EINVAL;
1040         }
1041
1042         /* Make sure the device was added through sysfs */
1043         res = -ENOENT;
1044         mutex_lock_nested(&adap->userspace_clients_lock,
1045                           i2c_adapter_depth(adap));
1046         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1047                                  detected) {
1048                 if (i2c_encode_flags_to_addr(client) == addr) {
1049                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1050                                  "delete_device", client->name, client->addr);
1051
1052                         list_del(&client->detected);
1053                         i2c_unregister_device(client);
1054                         res = count;
1055                         break;
1056                 }
1057         }
1058         mutex_unlock(&adap->userspace_clients_lock);
1059
1060         if (res < 0)
1061                 dev_err(dev, "%s: Can't find device in list\n",
1062                         "delete_device");
1063         return res;
1064 }
1065 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1066                                    i2c_sysfs_delete_device);
1067
1068 static struct attribute *i2c_adapter_attrs[] = {
1069         &dev_attr_name.attr,
1070         &dev_attr_new_device.attr,
1071         &dev_attr_delete_device.attr,
1072         NULL
1073 };
1074 ATTRIBUTE_GROUPS(i2c_adapter);
1075
1076 struct device_type i2c_adapter_type = {
1077         .groups         = i2c_adapter_groups,
1078         .release        = i2c_adapter_dev_release,
1079 };
1080 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1081
1082 /**
1083  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1084  * @dev: device, probably from some driver model iterator
1085  *
1086  * When traversing the driver model tree, perhaps using driver model
1087  * iterators like @device_for_each_child(), you can't assume very much
1088  * about the nodes you find.  Use this function to avoid oopses caused
1089  * by wrongly treating some non-I2C device as an i2c_adapter.
1090  */
1091 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1092 {
1093         return (dev->type == &i2c_adapter_type)
1094                         ? to_i2c_adapter(dev)
1095                         : NULL;
1096 }
1097 EXPORT_SYMBOL(i2c_verify_adapter);
1098
1099 #ifdef CONFIG_I2C_COMPAT
1100 static struct class_compat *i2c_adapter_compat_class;
1101 #endif
1102
1103 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1104 {
1105         struct i2c_devinfo      *devinfo;
1106
1107         down_read(&__i2c_board_lock);
1108         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1109                 if (devinfo->busnum == adapter->nr
1110                                 && !i2c_new_device(adapter,
1111                                                 &devinfo->board_info))
1112                         dev_err(&adapter->dev,
1113                                 "Can't create device at 0x%02x\n",
1114                                 devinfo->board_info.addr);
1115         }
1116         up_read(&__i2c_board_lock);
1117 }
1118
1119 static int i2c_do_add_adapter(struct i2c_driver *driver,
1120                               struct i2c_adapter *adap)
1121 {
1122         /* Detect supported devices on that bus, and instantiate them */
1123         i2c_detect(adap, driver);
1124
1125         /* Let legacy drivers scan this bus for matching devices */
1126         if (driver->attach_adapter) {
1127                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1128                          driver->driver.name);
1129                 dev_warn(&adap->dev,
1130                          "Please use another way to instantiate your i2c_client\n");
1131                 /* We ignore the return code; if it fails, too bad */
1132                 driver->attach_adapter(adap);
1133         }
1134         return 0;
1135 }
1136
1137 static int __process_new_adapter(struct device_driver *d, void *data)
1138 {
1139         return i2c_do_add_adapter(to_i2c_driver(d), data);
1140 }
1141
1142 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1143         .lock_bus =    i2c_adapter_lock_bus,
1144         .trylock_bus = i2c_adapter_trylock_bus,
1145         .unlock_bus =  i2c_adapter_unlock_bus,
1146 };
1147
1148 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1149 {
1150         struct irq_domain *domain = adap->host_notify_domain;
1151         irq_hw_number_t hwirq;
1152
1153         if (!domain)
1154                 return;
1155
1156         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1157                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1158
1159         irq_domain_remove(domain);
1160         adap->host_notify_domain = NULL;
1161 }
1162
1163 static int i2c_host_notify_irq_map(struct irq_domain *h,
1164                                           unsigned int virq,
1165                                           irq_hw_number_t hw_irq_num)
1166 {
1167         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1168
1169         return 0;
1170 }
1171
1172 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1173         .map = i2c_host_notify_irq_map,
1174 };
1175
1176 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1177 {
1178         struct irq_domain *domain;
1179
1180         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1181                 return 0;
1182
1183         domain = irq_domain_create_linear(adap->dev.fwnode,
1184                                           I2C_ADDR_7BITS_COUNT,
1185                                           &i2c_host_notify_irq_ops, adap);
1186         if (!domain)
1187                 return -ENOMEM;
1188
1189         adap->host_notify_domain = domain;
1190
1191         return 0;
1192 }
1193
1194 /**
1195  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1196  * I2C client.
1197  * @adap: the adapter
1198  * @addr: the I2C address of the notifying device
1199  * Context: can't sleep
1200  *
1201  * Helper function to be called from an I2C bus driver's interrupt
1202  * handler. It will schedule the Host Notify IRQ.
1203  */
1204 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1205 {
1206         int irq;
1207
1208         if (!adap)
1209                 return -EINVAL;
1210
1211         irq = irq_find_mapping(adap->host_notify_domain, addr);
1212         if (irq <= 0)
1213                 return -ENXIO;
1214
1215         generic_handle_irq(irq);
1216
1217         return 0;
1218 }
1219 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1220
1221 static int i2c_register_adapter(struct i2c_adapter *adap)
1222 {
1223         int res = -EINVAL;
1224
1225         /* Can't register until after driver model init */
1226         if (WARN_ON(!is_registered)) {
1227                 res = -EAGAIN;
1228                 goto out_list;
1229         }
1230
1231         /* Sanity checks */
1232         if (WARN(!adap->name[0], "i2c adapter has no name"))
1233                 goto out_list;
1234
1235         if (!adap->algo) {
1236                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1237                 goto out_list;
1238         }
1239
1240         if (!adap->lock_ops)
1241                 adap->lock_ops = &i2c_adapter_lock_ops;
1242
1243         rt_mutex_init(&adap->bus_lock);
1244         rt_mutex_init(&adap->mux_lock);
1245         mutex_init(&adap->userspace_clients_lock);
1246         INIT_LIST_HEAD(&adap->userspace_clients);
1247
1248         /* Set default timeout to 1 second if not already set */
1249         if (adap->timeout == 0)
1250                 adap->timeout = HZ;
1251
1252         /* register soft irqs for Host Notify */
1253         res = i2c_setup_host_notify_irq_domain(adap);
1254         if (res) {
1255                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1256                        adap->name, res);
1257                 goto out_list;
1258         }
1259
1260         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1261         adap->dev.bus = &i2c_bus_type;
1262         adap->dev.type = &i2c_adapter_type;
1263         res = device_register(&adap->dev);
1264         if (res) {
1265                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1266                 goto out_list;
1267         }
1268
1269         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1270
1271         pm_runtime_no_callbacks(&adap->dev);
1272         pm_suspend_ignore_children(&adap->dev, true);
1273         pm_runtime_enable(&adap->dev);
1274
1275 #ifdef CONFIG_I2C_COMPAT
1276         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1277                                        adap->dev.parent);
1278         if (res)
1279                 dev_warn(&adap->dev,
1280                          "Failed to create compatibility class link\n");
1281 #endif
1282
1283         i2c_init_recovery(adap);
1284
1285         /* create pre-declared device nodes */
1286         of_i2c_register_devices(adap);
1287         i2c_acpi_install_space_handler(adap);
1288         i2c_acpi_register_devices(adap);
1289
1290         if (adap->nr < __i2c_first_dynamic_bus_num)
1291                 i2c_scan_static_board_info(adap);
1292
1293         /* Notify drivers */
1294         mutex_lock(&core_lock);
1295         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1296         mutex_unlock(&core_lock);
1297
1298         return 0;
1299
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         if (client)
1428                 i2c_unregister_device(client);
1429         return 0;
1430 }
1431
1432 static int __process_removed_adapter(struct device_driver *d, void *data)
1433 {
1434         i2c_do_del_adapter(to_i2c_driver(d), data);
1435         return 0;
1436 }
1437
1438 /**
1439  * i2c_del_adapter - unregister I2C adapter
1440  * @adap: the adapter being unregistered
1441  * Context: can sleep
1442  *
1443  * This unregisters an I2C adapter which was previously registered
1444  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1445  */
1446 void i2c_del_adapter(struct i2c_adapter *adap)
1447 {
1448         struct i2c_adapter *found;
1449         struct i2c_client *client, *next;
1450
1451         /* First make sure that this adapter was ever added */
1452         mutex_lock(&core_lock);
1453         found = idr_find(&i2c_adapter_idr, adap->nr);
1454         mutex_unlock(&core_lock);
1455         if (found != adap) {
1456                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1457                 return;
1458         }
1459
1460         i2c_acpi_remove_space_handler(adap);
1461         /* Tell drivers about this removal */
1462         mutex_lock(&core_lock);
1463         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1464                                __process_removed_adapter);
1465         mutex_unlock(&core_lock);
1466
1467         /* Remove devices instantiated from sysfs */
1468         mutex_lock_nested(&adap->userspace_clients_lock,
1469                           i2c_adapter_depth(adap));
1470         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1471                                  detected) {
1472                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1473                         client->addr);
1474                 list_del(&client->detected);
1475                 i2c_unregister_device(client);
1476         }
1477         mutex_unlock(&adap->userspace_clients_lock);
1478
1479         /* Detach any active clients. This can't fail, thus we do not
1480          * check the returned value. This is a two-pass process, because
1481          * we can't remove the dummy devices during the first pass: they
1482          * could have been instantiated by real devices wishing to clean
1483          * them up properly, so we give them a chance to do that first. */
1484         device_for_each_child(&adap->dev, NULL, __unregister_client);
1485         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1486
1487 #ifdef CONFIG_I2C_COMPAT
1488         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1489                                  adap->dev.parent);
1490 #endif
1491
1492         /* device name is gone after device_unregister */
1493         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1494
1495         pm_runtime_disable(&adap->dev);
1496
1497         i2c_host_notify_irq_teardown(adap);
1498
1499         /* wait until all references to the device are gone
1500          *
1501          * FIXME: This is old code and should ideally be replaced by an
1502          * alternative which results in decoupling the lifetime of the struct
1503          * device from the i2c_adapter, like spi or netdev do. Any solution
1504          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1505          */
1506         init_completion(&adap->dev_released);
1507         device_unregister(&adap->dev);
1508         wait_for_completion(&adap->dev_released);
1509
1510         /* free bus id */
1511         mutex_lock(&core_lock);
1512         idr_remove(&i2c_adapter_idr, adap->nr);
1513         mutex_unlock(&core_lock);
1514
1515         /* Clear the device structure in case this adapter is ever going to be
1516            added again */
1517         memset(&adap->dev, 0, sizeof(adap->dev));
1518 }
1519 EXPORT_SYMBOL(i2c_del_adapter);
1520
1521 /**
1522  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1523  * @dev: The device to scan for I2C timing properties
1524  * @t: the i2c_timings struct to be filled with values
1525  * @use_defaults: bool to use sane defaults derived from the I2C specification
1526  *                when properties are not found, otherwise use 0
1527  *
1528  * Scan the device for the generic I2C properties describing timing parameters
1529  * for the signal and fill the given struct with the results. If a property was
1530  * not found and use_defaults was true, then maximum timings are assumed which
1531  * are derived from the I2C specification. If use_defaults is not used, the
1532  * results will be 0, so drivers can apply their own defaults later. The latter
1533  * is mainly intended for avoiding regressions of existing drivers which want
1534  * to switch to this function. New drivers almost always should use the defaults.
1535  */
1536
1537 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1538 {
1539         int ret;
1540
1541         memset(t, 0, sizeof(*t));
1542
1543         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1544         if (ret && use_defaults)
1545                 t->bus_freq_hz = 100000;
1546
1547         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1548         if (ret && use_defaults) {
1549                 if (t->bus_freq_hz <= 100000)
1550                         t->scl_rise_ns = 1000;
1551                 else if (t->bus_freq_hz <= 400000)
1552                         t->scl_rise_ns = 300;
1553                 else
1554                         t->scl_rise_ns = 120;
1555         }
1556
1557         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1558         if (ret && use_defaults) {
1559                 if (t->bus_freq_hz <= 400000)
1560                         t->scl_fall_ns = 300;
1561                 else
1562                         t->scl_fall_ns = 120;
1563         }
1564
1565         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1566
1567         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1568         if (ret && use_defaults)
1569                 t->sda_fall_ns = t->scl_fall_ns;
1570 }
1571 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1572
1573 /* ------------------------------------------------------------------------- */
1574
1575 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1576 {
1577         int res;
1578
1579         mutex_lock(&core_lock);
1580         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1581         mutex_unlock(&core_lock);
1582
1583         return res;
1584 }
1585 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1586
1587 static int __process_new_driver(struct device *dev, void *data)
1588 {
1589         if (dev->type != &i2c_adapter_type)
1590                 return 0;
1591         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1592 }
1593
1594 /*
1595  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1596  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1597  */
1598
1599 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1600 {
1601         int res;
1602
1603         /* Can't register until after driver model init */
1604         if (WARN_ON(!is_registered))
1605                 return -EAGAIN;
1606
1607         /* add the driver to the list of i2c drivers in the driver core */
1608         driver->driver.owner = owner;
1609         driver->driver.bus = &i2c_bus_type;
1610         INIT_LIST_HEAD(&driver->clients);
1611
1612         /* When registration returns, the driver core
1613          * will have called probe() for all matching-but-unbound devices.
1614          */
1615         res = driver_register(&driver->driver);
1616         if (res)
1617                 return res;
1618
1619         pr_debug("driver [%s] registered\n", driver->driver.name);
1620
1621         /* Walk the adapters that are already present */
1622         i2c_for_each_dev(driver, __process_new_driver);
1623
1624         return 0;
1625 }
1626 EXPORT_SYMBOL(i2c_register_driver);
1627
1628 static int __process_removed_driver(struct device *dev, void *data)
1629 {
1630         if (dev->type == &i2c_adapter_type)
1631                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1632         return 0;
1633 }
1634
1635 /**
1636  * i2c_del_driver - unregister I2C driver
1637  * @driver: the driver being unregistered
1638  * Context: can sleep
1639  */
1640 void i2c_del_driver(struct i2c_driver *driver)
1641 {
1642         i2c_for_each_dev(driver, __process_removed_driver);
1643
1644         driver_unregister(&driver->driver);
1645         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1646 }
1647 EXPORT_SYMBOL(i2c_del_driver);
1648
1649 /* ------------------------------------------------------------------------- */
1650
1651 /**
1652  * i2c_use_client - increments the reference count of the i2c client structure
1653  * @client: the client being referenced
1654  *
1655  * Each live reference to a client should be refcounted. The driver model does
1656  * that automatically as part of driver binding, so that most drivers don't
1657  * need to do this explicitly: they hold a reference until they're unbound
1658  * from the device.
1659  *
1660  * A pointer to the client with the incremented reference counter is returned.
1661  */
1662 struct i2c_client *i2c_use_client(struct i2c_client *client)
1663 {
1664         if (client && get_device(&client->dev))
1665                 return client;
1666         return NULL;
1667 }
1668 EXPORT_SYMBOL(i2c_use_client);
1669
1670 /**
1671  * i2c_release_client - release a use of the i2c client structure
1672  * @client: the client being no longer referenced
1673  *
1674  * Must be called when a user of a client is finished with it.
1675  */
1676 void i2c_release_client(struct i2c_client *client)
1677 {
1678         if (client)
1679                 put_device(&client->dev);
1680 }
1681 EXPORT_SYMBOL(i2c_release_client);
1682
1683 struct i2c_cmd_arg {
1684         unsigned        cmd;
1685         void            *arg;
1686 };
1687
1688 static int i2c_cmd(struct device *dev, void *_arg)
1689 {
1690         struct i2c_client       *client = i2c_verify_client(dev);
1691         struct i2c_cmd_arg      *arg = _arg;
1692         struct i2c_driver       *driver;
1693
1694         if (!client || !client->dev.driver)
1695                 return 0;
1696
1697         driver = to_i2c_driver(client->dev.driver);
1698         if (driver->command)
1699                 driver->command(client, arg->cmd, arg->arg);
1700         return 0;
1701 }
1702
1703 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1704 {
1705         struct i2c_cmd_arg      cmd_arg;
1706
1707         cmd_arg.cmd = cmd;
1708         cmd_arg.arg = arg;
1709         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1710 }
1711 EXPORT_SYMBOL(i2c_clients_command);
1712
1713 static int __init i2c_init(void)
1714 {
1715         int retval;
1716
1717         retval = of_alias_get_highest_id("i2c");
1718
1719         down_write(&__i2c_board_lock);
1720         if (retval >= __i2c_first_dynamic_bus_num)
1721                 __i2c_first_dynamic_bus_num = retval + 1;
1722         up_write(&__i2c_board_lock);
1723
1724         retval = bus_register(&i2c_bus_type);
1725         if (retval)
1726                 return retval;
1727
1728         is_registered = true;
1729
1730 #ifdef CONFIG_I2C_COMPAT
1731         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1732         if (!i2c_adapter_compat_class) {
1733                 retval = -ENOMEM;
1734                 goto bus_err;
1735         }
1736 #endif
1737         retval = i2c_add_driver(&dummy_driver);
1738         if (retval)
1739                 goto class_err;
1740
1741         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1742                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1743         if (IS_ENABLED(CONFIG_ACPI))
1744                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1745
1746         return 0;
1747
1748 class_err:
1749 #ifdef CONFIG_I2C_COMPAT
1750         class_compat_unregister(i2c_adapter_compat_class);
1751 bus_err:
1752 #endif
1753         is_registered = false;
1754         bus_unregister(&i2c_bus_type);
1755         return retval;
1756 }
1757
1758 static void __exit i2c_exit(void)
1759 {
1760         if (IS_ENABLED(CONFIG_ACPI))
1761                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1762         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1763                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1764         i2c_del_driver(&dummy_driver);
1765 #ifdef CONFIG_I2C_COMPAT
1766         class_compat_unregister(i2c_adapter_compat_class);
1767 #endif
1768         bus_unregister(&i2c_bus_type);
1769         tracepoint_synchronize_unregister();
1770 }
1771
1772 /* We must initialize early, because some subsystems register i2c drivers
1773  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1774  */
1775 postcore_initcall(i2c_init);
1776 module_exit(i2c_exit);
1777
1778 /* ----------------------------------------------------
1779  * the functional interface to the i2c busses.
1780  * ----------------------------------------------------
1781  */
1782
1783 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1784 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1785
1786 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1787 {
1788         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1789                             err_msg, msg->addr, msg->len,
1790                             msg->flags & I2C_M_RD ? "read" : "write");
1791         return -EOPNOTSUPP;
1792 }
1793
1794 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1795 {
1796         const struct i2c_adapter_quirks *q = adap->quirks;
1797         int max_num = q->max_num_msgs, i;
1798         bool do_len_check = true;
1799
1800         if (q->flags & I2C_AQ_COMB) {
1801                 max_num = 2;
1802
1803                 /* special checks for combined messages */
1804                 if (num == 2) {
1805                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1806                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1807
1808                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1809                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1810
1811                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1812                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1813
1814                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1815                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1816
1817                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1818                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1819
1820                         do_len_check = false;
1821                 }
1822         }
1823
1824         if (i2c_quirk_exceeded(num, max_num))
1825                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1826
1827         for (i = 0; i < num; i++) {
1828                 u16 len = msgs[i].len;
1829
1830                 if (msgs[i].flags & I2C_M_RD) {
1831                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1832                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1833                 } else {
1834                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1835                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1836                 }
1837         }
1838
1839         return 0;
1840 }
1841
1842 /**
1843  * __i2c_transfer - unlocked flavor of i2c_transfer
1844  * @adap: Handle to I2C bus
1845  * @msgs: One or more messages to execute before STOP is issued to
1846  *      terminate the operation; each message begins with a START.
1847  * @num: Number of messages to be executed.
1848  *
1849  * Returns negative errno, else the number of messages executed.
1850  *
1851  * Adapter lock must be held when calling this function. No debug logging
1852  * takes place. adap->algo->master_xfer existence isn't checked.
1853  */
1854 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1855 {
1856         unsigned long orig_jiffies;
1857         int ret, try;
1858
1859         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1860                 return -EOPNOTSUPP;
1861
1862         /* i2c_trace_msg 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_key_false(&i2c_trace_msg)) {
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_key_false(&i2c_trace_msg)) {
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, i, 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_master_send - issue a single I2C message in master transmit mode
1963  * @client: Handle to slave device
1964  * @buf: Data that will be written to the slave
1965  * @count: How many bytes to write, must be less than 64k since msg.len is u16
1966  *
1967  * Returns negative errno, or else the number of bytes written.
1968  */
1969 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1970 {
1971         int ret;
1972         struct i2c_adapter *adap = client->adapter;
1973         struct i2c_msg msg;
1974
1975         msg.addr = client->addr;
1976         msg.flags = client->flags & I2C_M_TEN;
1977         msg.len = count;
1978         msg.buf = (char *)buf;
1979
1980         ret = i2c_transfer(adap, &msg, 1);
1981
1982         /*
1983          * If everything went ok (i.e. 1 msg transmitted), return #bytes
1984          * transmitted, else error code.
1985          */
1986         return (ret == 1) ? count : ret;
1987 }
1988 EXPORT_SYMBOL(i2c_master_send);
1989
1990 /**
1991  * i2c_master_recv - issue a single I2C message in master receive mode
1992  * @client: Handle to slave device
1993  * @buf: Where to store data read from slave
1994  * @count: How many bytes to read, must be less than 64k since msg.len is u16
1995  *
1996  * Returns negative errno, or else the number of bytes read.
1997  */
1998 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1999 {
2000         struct i2c_adapter *adap = client->adapter;
2001         struct i2c_msg msg;
2002         int ret;
2003
2004         msg.addr = client->addr;
2005         msg.flags = client->flags & I2C_M_TEN;
2006         msg.flags |= I2C_M_RD;
2007         msg.len = count;
2008         msg.buf = buf;
2009
2010         ret = i2c_transfer(adap, &msg, 1);
2011
2012         /*
2013          * If everything went ok (i.e. 1 msg received), return #bytes received,
2014          * else error code.
2015          */
2016         return (ret == 1) ? count : ret;
2017 }
2018 EXPORT_SYMBOL(i2c_master_recv);
2019
2020 /* ----------------------------------------------------
2021  * the i2c address scanning function
2022  * Will not work for 10-bit addresses!
2023  * ----------------------------------------------------
2024  */
2025
2026 /*
2027  * Legacy default probe function, mostly relevant for SMBus. The default
2028  * probe method is a quick write, but it is known to corrupt the 24RF08
2029  * EEPROMs due to a state machine bug, and could also irreversibly
2030  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2031  * we use a short byte read instead. Also, some bus drivers don't implement
2032  * quick write, so we fallback to a byte read in that case too.
2033  * On x86, there is another special case for FSC hardware monitoring chips,
2034  * which want regular byte reads (address 0x73.) Fortunately, these are the
2035  * only known chips using this I2C address on PC hardware.
2036  * Returns 1 if probe succeeded, 0 if not.
2037  */
2038 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2039 {
2040         int err;
2041         union i2c_smbus_data dummy;
2042
2043 #ifdef CONFIG_X86
2044         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2045          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2046                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2047                                      I2C_SMBUS_BYTE_DATA, &dummy);
2048         else
2049 #endif
2050         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2051          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2052                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2053                                      I2C_SMBUS_QUICK, NULL);
2054         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2055                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2056                                      I2C_SMBUS_BYTE, &dummy);
2057         else {
2058                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2059                          addr);
2060                 err = -EOPNOTSUPP;
2061         }
2062
2063         return err >= 0;
2064 }
2065
2066 static int i2c_detect_address(struct i2c_client *temp_client,
2067                               struct i2c_driver *driver)
2068 {
2069         struct i2c_board_info info;
2070         struct i2c_adapter *adapter = temp_client->adapter;
2071         int addr = temp_client->addr;
2072         int err;
2073
2074         /* Make sure the address is valid */
2075         err = i2c_check_7bit_addr_validity_strict(addr);
2076         if (err) {
2077                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2078                          addr);
2079                 return err;
2080         }
2081
2082         /* Skip if already in use (7 bit, no need to encode flags) */
2083         if (i2c_check_addr_busy(adapter, addr))
2084                 return 0;
2085
2086         /* Make sure there is something at this address */
2087         if (!i2c_default_probe(adapter, addr))
2088                 return 0;
2089
2090         /* Finally call the custom detection function */
2091         memset(&info, 0, sizeof(struct i2c_board_info));
2092         info.addr = addr;
2093         err = driver->detect(temp_client, &info);
2094         if (err) {
2095                 /* -ENODEV is returned if the detection fails. We catch it
2096                    here as this isn't an error. */
2097                 return err == -ENODEV ? 0 : err;
2098         }
2099
2100         /* Consistency check */
2101         if (info.type[0] == '\0') {
2102                 dev_err(&adapter->dev,
2103                         "%s detection function provided no name for 0x%x\n",
2104                         driver->driver.name, addr);
2105         } else {
2106                 struct i2c_client *client;
2107
2108                 /* Detection succeeded, instantiate the device */
2109                 if (adapter->class & I2C_CLASS_DEPRECATED)
2110                         dev_warn(&adapter->dev,
2111                                 "This adapter will soon drop class based instantiation of devices. "
2112                                 "Please make sure client 0x%02x gets instantiated by other means. "
2113                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2114                                 info.addr);
2115
2116                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2117                         info.type, info.addr);
2118                 client = i2c_new_device(adapter, &info);
2119                 if (client)
2120                         list_add_tail(&client->detected, &driver->clients);
2121                 else
2122                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2123                                 info.type, info.addr);
2124         }
2125         return 0;
2126 }
2127
2128 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2129 {
2130         const unsigned short *address_list;
2131         struct i2c_client *temp_client;
2132         int i, err = 0;
2133         int adap_id = i2c_adapter_id(adapter);
2134
2135         address_list = driver->address_list;
2136         if (!driver->detect || !address_list)
2137                 return 0;
2138
2139         /* Warn that the adapter lost class based instantiation */
2140         if (adapter->class == I2C_CLASS_DEPRECATED) {
2141                 dev_dbg(&adapter->dev,
2142                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2143                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2144                         driver->driver.name);
2145                 return 0;
2146         }
2147
2148         /* Stop here if the classes do not match */
2149         if (!(adapter->class & driver->class))
2150                 return 0;
2151
2152         /* Set up a temporary client to help detect callback */
2153         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2154         if (!temp_client)
2155                 return -ENOMEM;
2156         temp_client->adapter = adapter;
2157
2158         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2159                 dev_dbg(&adapter->dev,
2160                         "found normal entry for adapter %d, addr 0x%02x\n",
2161                         adap_id, address_list[i]);
2162                 temp_client->addr = address_list[i];
2163                 err = i2c_detect_address(temp_client, driver);
2164                 if (unlikely(err))
2165                         break;
2166         }
2167
2168         kfree(temp_client);
2169         return err;
2170 }
2171
2172 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2173 {
2174         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2175                               I2C_SMBUS_QUICK, NULL) >= 0;
2176 }
2177 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2178
2179 struct i2c_client *
2180 i2c_new_probed_device(struct i2c_adapter *adap,
2181                       struct i2c_board_info *info,
2182                       unsigned short const *addr_list,
2183                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2184 {
2185         int i;
2186
2187         if (!probe)
2188                 probe = i2c_default_probe;
2189
2190         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2191                 /* Check address validity */
2192                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2193                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2194                                  addr_list[i]);
2195                         continue;
2196                 }
2197
2198                 /* Check address availability (7 bit, no need to encode flags) */
2199                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2200                         dev_dbg(&adap->dev,
2201                                 "Address 0x%02x already in use, not probing\n",
2202                                 addr_list[i]);
2203                         continue;
2204                 }
2205
2206                 /* Test address responsiveness */
2207                 if (probe(adap, addr_list[i]))
2208                         break;
2209         }
2210
2211         if (addr_list[i] == I2C_CLIENT_END) {
2212                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2213                 return NULL;
2214         }
2215
2216         info->addr = addr_list[i];
2217         return i2c_new_device(adap, info);
2218 }
2219 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2220
2221 struct i2c_adapter *i2c_get_adapter(int nr)
2222 {
2223         struct i2c_adapter *adapter;
2224
2225         mutex_lock(&core_lock);
2226         adapter = idr_find(&i2c_adapter_idr, nr);
2227         if (!adapter)
2228                 goto exit;
2229
2230         if (try_module_get(adapter->owner))
2231                 get_device(&adapter->dev);
2232         else
2233                 adapter = NULL;
2234
2235  exit:
2236         mutex_unlock(&core_lock);
2237         return adapter;
2238 }
2239 EXPORT_SYMBOL(i2c_get_adapter);
2240
2241 void i2c_put_adapter(struct i2c_adapter *adap)
2242 {
2243         if (!adap)
2244                 return;
2245
2246         module_put(adap->owner);
2247         /* Should be last, otherwise we risk use-after-free with 'adap' */
2248         put_device(&adap->dev);
2249 }
2250 EXPORT_SYMBOL(i2c_put_adapter);
2251
2252 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2253 MODULE_DESCRIPTION("I2C-Bus main module");
2254 MODULE_LICENSE("GPL");