drivers/i2c/i2c-core-base.c

   1 /*
   2  * Linux I2C core
   3  *
   4  * Copyright (C) 1995-99 Simon G. Vogl
   5  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   6  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   7  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   8  *
   9  * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  19  */
  20
  21 #define pr_fmt(fmt) "i2c-core: " fmt
  22
  23 #include <dt-bindings/i2c/i2c.h>
  24 #include <linux/acpi.h>
  25 #include <linux/clk/clk-conf.h>
  26 #include <linux/completion.h>
  27 #include <linux/delay.h>
  28 #include <linux/err.h>
  29 #include <linux/errno.h>
  30 #include <linux/gpio/consumer.h>
  31 #include <linux/i2c.h>
  32 #include <linux/i2c-smbus.h>
  33 #include <linux/idr.h>
  34 #include <linux/init.h>
  35 #include <linux/irqflags.h>
  36 #include <linux/jump_label.h>
  37 #include <linux/kernel.h>
  38 #include <linux/module.h>
  39 #include <linux/mutex.h>
  40 #include <linux/of_device.h>
  41 #include <linux/of.h>
  42 #include <linux/of_irq.h>
  43 #include <linux/pm_domain.h>
  44 #include <linux/pm_runtime.h>
  45 #include <linux/pm_wakeirq.h>
  46 #include <linux/property.h>
  47 #include <linux/rwsem.h>
  48 #include <linux/slab.h>
  49
  50 #include "i2c-core.h"
  51
  52 #define CREATE_TRACE_POINTS
  53 #include <trace/events/i2c.h>
  54
  55 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
  56 #define I2C_ADDR_OFFSET_SLAVE   0x1000
  57
  58 #define I2C_ADDR_7BITS_MAX      0x77
  59 #define I2C_ADDR_7BITS_COUNT    (I2C_ADDR_7BITS_MAX + 1)
  60
  61 #define I2C_ADDR_DEVICE_ID      0x7c
  62
  63 /*
  64  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  65  * deletion of detected devices, and attach_adapter calls are serialized
  66  */
  67 static DEFINE_MUTEX(core_lock);
  68 static DEFINE_IDR(i2c_adapter_idr);
  69
  70 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  71
  72 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
  73 static bool is_registered;
  74
  75 int i2c_transfer_trace_reg(void)
  76 {
  77         static_branch_inc(&i2c_trace_msg_key);
  78         return 0;
  79 }
  80
  81 void i2c_transfer_trace_unreg(void)
  82 {
  83         static_branch_dec(&i2c_trace_msg_key);
  84 }
  85
  86 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  87                                                 const struct i2c_client *client)
  88 {
  89         if (!(id && client))
  90                 return NULL;
  91
  92         while (id->name[0]) {
  93                 if (strcmp(client->name, id->name) == 0)
  94                         return id;
  95                 id++;
  96         }
  97         return NULL;
  98 }
  99 EXPORT_SYMBOL_GPL(i2c_match_id);
 100
 101 static int i2c_device_match(struct device *dev, struct device_driver *drv)
 102 {
 103         struct i2c_client       *client = i2c_verify_client(dev);
 104         struct i2c_driver       *driver;
 105
 106
 107         /* Attempt an OF style match */
 108         if (i2c_of_match_device(drv->of_match_table, client))
 109                 return 1;
 110
 111         /* Then ACPI style match */
 112         if (acpi_driver_match_device(dev, drv))
 113                 return 1;
 114
 115         driver = to_i2c_driver(drv);
 116
 117         /* Finally an I2C match */
 118         if (i2c_match_id(driver->id_table, client))
 119                 return 1;
 120
 121         return 0;
 122 }
 123
 124 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 125 {
 126         struct i2c_client *client = to_i2c_client(dev);
 127         int rc;
 128
 129         rc = of_device_uevent_modalias(dev, env);
 130         if (rc != -ENODEV)
 131                 return rc;
 132
 133         rc = acpi_device_uevent_modalias(dev, env);
 134         if (rc != -ENODEV)
 135                 return rc;
 136
 137         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 138 }
 139
 140 /* i2c bus recovery routines */
 141 static int get_scl_gpio_value(struct i2c_adapter *adap)
 142 {
 143         return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 144 }
 145
 146 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 147 {
 148         gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 149 }
 150
 151 static int get_sda_gpio_value(struct i2c_adapter *adap)
 152 {
 153         return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 154 }
 155
 156 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 157 {
 158         gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 159 }
 160
 161 /*
 162  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 163  * We will generate clock with rate 100 KHz and so duration of both clock levels
 164  * is: delay in ns = (10^6 / 100) / 2
 165  */
 166 #define RECOVERY_NDELAY         5000
 167 #define RECOVERY_CLK_CNT        9
 168
 169 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 170 {
 171         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 172         int i = 0, val = 1, ret = 0;
 173
 174         if (bri->prepare_recovery)
 175                 bri->prepare_recovery(adap);
 176
 177         bri->set_scl(adap, val);
 178         if (bri->set_sda)
 179                 bri->set_sda(adap, 1);
 180         ndelay(RECOVERY_NDELAY);
 181
 182         /*
 183          * By this time SCL is high, as we need to give 9 falling-rising edges
 184          */
 185         while (i++ < RECOVERY_CLK_CNT * 2) {
 186                 if (val) {
 187                         /* SCL shouldn't be low here */
 188                         if (!bri->get_scl(adap)) {
 189                                 dev_err(&adap->dev,
 190                                         "SCL is stuck low, exit recovery\n");
 191                                 ret = -EBUSY;
 192                                 break;
 193                         }
 194                         /* Break if SDA is high */
 195                         if (bri->get_sda && bri->get_sda(adap))
 196                                 break;
 197                 }
 198
 199                 val = !val;
 200                 bri->set_scl(adap, val);
 201                 ndelay(RECOVERY_NDELAY);
 202         }
 203
 204         /* check if recovery actually succeeded */
 205         if (bri->get_sda && !bri->get_sda(adap))
 206                 ret = -EBUSY;
 207
 208         /* If all went well, send STOP for a sane bus state. */
 209         if (ret == 0 && bri->set_sda) {
 210                 bri->set_scl(adap, 0);
 211                 ndelay(RECOVERY_NDELAY / 2);
 212                 bri->set_sda(adap, 0);
 213                 ndelay(RECOVERY_NDELAY / 2);
 214                 bri->set_scl(adap, 1);
 215                 ndelay(RECOVERY_NDELAY / 2);
 216                 bri->set_sda(adap, 1);
 217                 ndelay(RECOVERY_NDELAY / 2);
 218         }
 219
 220         if (bri->unprepare_recovery)
 221                 bri->unprepare_recovery(adap);
 222
 223         return ret;
 224 }
 225 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 226
 227 int i2c_recover_bus(struct i2c_adapter *adap)
 228 {
 229         if (!adap->bus_recovery_info)
 230                 return -EOPNOTSUPP;
 231
 232         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 233         return adap->bus_recovery_info->recover_bus(adap);
 234 }
 235 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 236
 237 static void i2c_init_recovery(struct i2c_adapter *adap)
 238 {
 239         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 240         char *err_str;
 241
 242         if (!bri)
 243                 return;
 244
 245         if (!bri->recover_bus) {
 246                 err_str = "no recover_bus() found";
 247                 goto err;
 248         }
 249
 250         if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 251                 bri->get_scl = get_scl_gpio_value;
 252                 bri->set_scl = set_scl_gpio_value;
 253                 if (bri->sda_gpiod) {
 254                         bri->get_sda = get_sda_gpio_value;
 255                         /* FIXME: add proper flag instead of '0' once available */
 256                         if (gpiod_get_direction(bri->sda_gpiod) == 0)
 257                                 bri->set_sda = set_sda_gpio_value;
 258                 }
 259                 return;
 260         }
 261
 262         if (bri->recover_bus == i2c_generic_scl_recovery) {
 263                 /* Generic SCL recovery */
 264                 if (!bri->set_scl || !bri->get_scl) {
 265                         err_str = "no {get|set}_scl() found";
 266                         goto err;
 267                 }
 268         }
 269
 270         return;
 271  err:
 272         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 273         adap->bus_recovery_info = NULL;
 274 }
 275
 276 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 277 {
 278         struct i2c_adapter *adap = client->adapter;
 279         unsigned int irq;
 280
 281         if (!adap->host_notify_domain)
 282                 return -ENXIO;
 283
 284         if (client->flags & I2C_CLIENT_TEN)
 285                 return -EINVAL;
 286
 287         irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 288         if (!irq)
 289                 irq = irq_create_mapping(adap->host_notify_domain,
 290                                          client->addr);
 291
 292         return irq > 0 ? irq : -ENXIO;
 293 }
 294
 295 static int i2c_device_probe(struct device *dev)
 296 {
 297         struct i2c_client       *client = i2c_verify_client(dev);
 298         struct i2c_driver       *driver;
 299         int status;
 300
 301         if (!client)
 302                 return 0;
 303
 304         driver = to_i2c_driver(dev->driver);
 305
 306         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 307                 int irq = -ENOENT;
 308
 309                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 310                         dev_dbg(dev, "Using Host Notify IRQ\n");
 311                         irq = i2c_smbus_host_notify_to_irq(client);
 312                 } else if (dev->of_node) {
 313                         irq = of_irq_get_byname(dev->of_node, "irq");
 314                         if (irq == -EINVAL || irq == -ENODATA)
 315                                 irq = of_irq_get(dev->of_node, 0);
 316                 } else if (ACPI_COMPANION(dev)) {
 317                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 318                 }
 319                 if (irq == -EPROBE_DEFER)
 320                         return irq;
 321
 322                 if (irq < 0)
 323                         irq = 0;
 324
 325                 client->irq = irq;
 326         }
 327
 328         /*
 329          * An I2C ID table is not mandatory, if and only if, a suitable OF
 330          * or ACPI ID table is supplied for the probing device.
 331          */
 332         if (!driver->id_table &&
 333             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 334             !i2c_of_match_device(dev->driver->of_match_table, client))
 335                 return -ENODEV;
 336
 337         if (client->flags & I2C_CLIENT_WAKE) {
 338                 int wakeirq = -ENOENT;
 339
 340                 if (dev->of_node) {
 341                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 342                         if (wakeirq == -EPROBE_DEFER)
 343                                 return wakeirq;
 344                 }
 345
 346                 device_init_wakeup(&client->dev, true);
 347
 348                 if (wakeirq > 0 && wakeirq != client->irq)
 349                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 350                 else if (client->irq > 0)
 351                         status = dev_pm_set_wake_irq(dev, client->irq);
 352                 else
 353                         status = 0;
 354
 355                 if (status)
 356                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 357         }
 358
 359         dev_dbg(dev, "probe\n");
 360
 361         status = of_clk_set_defaults(dev->of_node, false);
 362         if (status < 0)
 363                 goto err_clear_wakeup_irq;
 364
 365         status = dev_pm_domain_attach(&client->dev, true);
 366         if (status == -EPROBE_DEFER)
 367                 goto err_clear_wakeup_irq;
 368
 369         /*
 370          * When there are no more users of probe(),
 371          * rename probe_new to probe.
 372          */
 373         if (driver->probe_new)
 374                 status = driver->probe_new(client);
 375         else if (driver->probe)
 376                 status = driver->probe(client,
 377                                        i2c_match_id(driver->id_table, client));
 378         else
 379                 status = -EINVAL;
 380
 381         if (status)
 382                 goto err_detach_pm_domain;
 383
 384         return 0;
 385
 386 err_detach_pm_domain:
 387         dev_pm_domain_detach(&client->dev, true);
 388 err_clear_wakeup_irq:
 389         dev_pm_clear_wake_irq(&client->dev);
 390         device_init_wakeup(&client->dev, false);
 391         return status;
 392 }
 393
 394 static int i2c_device_remove(struct device *dev)
 395 {
 396         struct i2c_client       *client = i2c_verify_client(dev);
 397         struct i2c_driver       *driver;
 398         int status = 0;
 399
 400         if (!client || !dev->driver)
 401                 return 0;
 402
 403         driver = to_i2c_driver(dev->driver);
 404         if (driver->remove) {
 405                 dev_dbg(dev, "remove\n");
 406                 status = driver->remove(client);
 407         }
 408
 409         dev_pm_domain_detach(&client->dev, true);
 410
 411         dev_pm_clear_wake_irq(&client->dev);
 412         device_init_wakeup(&client->dev, false);
 413
 414         return status;
 415 }
 416
 417 static void i2c_device_shutdown(struct device *dev)
 418 {
 419         struct i2c_client *client = i2c_verify_client(dev);
 420         struct i2c_driver *driver;
 421
 422         if (!client || !dev->driver)
 423                 return;
 424         driver = to_i2c_driver(dev->driver);
 425         if (driver->shutdown)
 426                 driver->shutdown(client);
 427 }
 428
 429 static void i2c_client_dev_release(struct device *dev)
 430 {
 431         kfree(to_i2c_client(dev));
 432 }
 433
 434 static ssize_t
 435 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 436 {
 437         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 438                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 439 }
 440 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 441
 442 static ssize_t
 443 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 444 {
 445         struct i2c_client *client = to_i2c_client(dev);
 446         int len;
 447
 448         len = of_device_modalias(dev, buf, PAGE_SIZE);
 449         if (len != -ENODEV)
 450                 return len;
 451
 452         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 453         if (len != -ENODEV)
 454                 return len;
 455
 456         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 457 }
 458 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 459
 460 static struct attribute *i2c_dev_attrs[] = {
 461         &dev_attr_name.attr,
 462         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 463         &dev_attr_modalias.attr,
 464         NULL
 465 };
 466 ATTRIBUTE_GROUPS(i2c_dev);
 467
 468 struct bus_type i2c_bus_type = {
 469         .name           = "i2c",
 470         .match          = i2c_device_match,
 471         .probe          = i2c_device_probe,
 472         .remove         = i2c_device_remove,
 473         .shutdown       = i2c_device_shutdown,
 474 };
 475 EXPORT_SYMBOL_GPL(i2c_bus_type);
 476
 477 struct device_type i2c_client_type = {
 478         .groups         = i2c_dev_groups,
 479         .uevent         = i2c_device_uevent,
 480         .release        = i2c_client_dev_release,
 481 };
 482 EXPORT_SYMBOL_GPL(i2c_client_type);
 483
 484
 485 /**
 486  * i2c_verify_client - return parameter as i2c_client, or NULL
 487  * @dev: device, probably from some driver model iterator
 488  *
 489  * When traversing the driver model tree, perhaps using driver model
 490  * iterators like @device_for_each_child(), you can't assume very much
 491  * about the nodes you find.  Use this function to avoid oopses caused
 492  * by wrongly treating some non-I2C device as an i2c_client.
 493  */
 494 struct i2c_client *i2c_verify_client(struct device *dev)
 495 {
 496         return (dev->type == &i2c_client_type)
 497                         ? to_i2c_client(dev)
 498                         : NULL;
 499 }
 500 EXPORT_SYMBOL(i2c_verify_client);
 501
 502
 503 /* Return a unique address which takes the flags of the client into account */
 504 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 505 {
 506         unsigned short addr = client->addr;
 507
 508         /* For some client flags, add an arbitrary offset to avoid collisions */
 509         if (client->flags & I2C_CLIENT_TEN)
 510                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 511
 512         if (client->flags & I2C_CLIENT_SLAVE)
 513                 addr |= I2C_ADDR_OFFSET_SLAVE;
 514
 515         return addr;
 516 }
 517
 518 /* This is a permissive address validity check, I2C address map constraints
 519  * are purposely not enforced, except for the general call address. */
 520 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 521 {
 522         if (flags & I2C_CLIENT_TEN) {
 523                 /* 10-bit address, all values are valid */
 524                 if (addr > 0x3ff)
 525                         return -EINVAL;
 526         } else {
 527                 /* 7-bit address, reject the general call address */
 528                 if (addr == 0x00 || addr > 0x7f)
 529                         return -EINVAL;
 530         }
 531         return 0;
 532 }
 533
 534 /* And this is a strict address validity check, used when probing. If a
 535  * device uses a reserved address, then it shouldn't be probed. 7-bit
 536  * addressing is assumed, 10-bit address devices are rare and should be
 537  * explicitly enumerated. */
 538 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 539 {
 540         /*
 541          * Reserved addresses per I2C specification:
 542          *  0x00       General call address / START byte
 543          *  0x01       CBUS address
 544          *  0x02       Reserved for different bus format
 545          *  0x03       Reserved for future purposes
 546          *  0x04-0x07  Hs-mode master code
 547          *  0x78-0x7b  10-bit slave addressing
 548          *  0x7c-0x7f  Reserved for future purposes
 549          */
 550         if (addr < 0x08 || addr > 0x77)
 551                 return -EINVAL;
 552         return 0;
 553 }
 554
 555 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 556 {
 557         struct i2c_client       *client = i2c_verify_client(dev);
 558         int                     addr = *(int *)addrp;
 559
 560         if (client && i2c_encode_flags_to_addr(client) == addr)
 561                 return -EBUSY;
 562         return 0;
 563 }
 564
 565 /* walk up mux tree */
 566 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 567 {
 568         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 569         int result;
 570
 571         result = device_for_each_child(&adapter->dev, &addr,
 572                                         __i2c_check_addr_busy);
 573
 574         if (!result && parent)
 575                 result = i2c_check_mux_parents(parent, addr);
 576
 577         return result;
 578 }
 579
 580 /* recurse down mux tree */
 581 static int i2c_check_mux_children(struct device *dev, void *addrp)
 582 {
 583         int result;
 584
 585         if (dev->type == &i2c_adapter_type)
 586                 result = device_for_each_child(dev, addrp,
 587                                                 i2c_check_mux_children);
 588         else
 589                 result = __i2c_check_addr_busy(dev, addrp);
 590
 591         return result;
 592 }
 593
 594 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 595 {
 596         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 597         int result = 0;
 598
 599         if (parent)
 600                 result = i2c_check_mux_parents(parent, addr);
 601
 602         if (!result)
 603                 result = device_for_each_child(&adapter->dev, &addr,
 604                                                 i2c_check_mux_children);
 605
 606         return result;
 607 }
 608
 609 /**
 610  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 611  * @adapter: Target I2C bus segment
 612  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 613  *      locks only this branch in the adapter tree
 614  */
 615 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 616                                  unsigned int flags)
 617 {
 618         rt_mutex_lock(&adapter->bus_lock);
 619 }
 620
 621 /**
 622  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 623  * @adapter: Target I2C bus segment
 624  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 625  *      trylocks only this branch in the adapter tree
 626  */
 627 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 628                                    unsigned int flags)
 629 {
 630         return rt_mutex_trylock(&adapter->bus_lock);
 631 }
 632
 633 /**
 634  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 635  * @adapter: Target I2C bus segment
 636  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 637  *      unlocks only this branch in the adapter tree
 638  */
 639 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 640                                    unsigned int flags)
 641 {
 642         rt_mutex_unlock(&adapter->bus_lock);
 643 }
 644
 645 static void i2c_dev_set_name(struct i2c_adapter *adap,
 646                              struct i2c_client *client,
 647                              struct i2c_board_info const *info)
 648 {
 649         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 650
 651         if (info && info->dev_name) {
 652                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 653                 return;
 654         }
 655
 656         if (adev) {
 657                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 658                 return;
 659         }
 660
 661         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 662                      i2c_encode_flags_to_addr(client));
 663 }
 664
 665 static int i2c_dev_irq_from_resources(const struct resource *resources,
 666                                       unsigned int num_resources)
 667 {
 668         struct irq_data *irqd;
 669         int i;
 670
 671         for (i = 0; i < num_resources; i++) {
 672                 const struct resource *r = &resources[i];
 673
 674                 if (resource_type(r) != IORESOURCE_IRQ)
 675                         continue;
 676
 677                 if (r->flags & IORESOURCE_BITS) {
 678                         irqd = irq_get_irq_data(r->start);
 679                         if (!irqd)
 680                                 break;
 681
 682                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 683                 }
 684
 685                 return r->start;
 686         }
 687
 688         return 0;
 689 }
 690
 691 /**
 692  * i2c_new_device - instantiate an i2c device
 693  * @adap: the adapter managing the device
 694  * @info: describes one I2C device; bus_num is ignored
 695  * Context: can sleep
 696  *
 697  * Create an i2c device. Binding is handled through driver model
 698  * probe()/remove() methods.  A driver may be bound to this device when we
 699  * return from this function, or any later moment (e.g. maybe hotplugging will
 700  * load the driver module).  This call is not appropriate for use by mainboard
 701  * initialization logic, which usually runs during an arch_initcall() long
 702  * before any i2c_adapter could exist.
 703  *
 704  * This returns the new i2c client, which may be saved for later use with
 705  * i2c_unregister_device(); or NULL to indicate an error.
 706  */
 707 struct i2c_client *
 708 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 709 {
 710         struct i2c_client       *client;
 711         int                     status;
 712
 713         client = kzalloc(sizeof *client, GFP_KERNEL);
 714         if (!client)
 715                 return NULL;
 716
 717         client->adapter = adap;
 718
 719         client->dev.platform_data = info->platform_data;
 720
 721         if (info->archdata)
 722                 client->dev.archdata = *info->archdata;
 723
 724         client->flags = info->flags;
 725         client->addr = info->addr;
 726
 727         client->irq = info->irq;
 728         if (!client->irq)
 729                 client->irq = i2c_dev_irq_from_resources(info->resources,
 730                                                          info->num_resources);
 731
 732         strlcpy(client->name, info->type, sizeof(client->name));
 733
 734         status = i2c_check_addr_validity(client->addr, client->flags);
 735         if (status) {
 736                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 737                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 738                 goto out_err_silent;
 739         }
 740
 741         /* Check for address business */
 742         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 743         if (status)
 744                 goto out_err;
 745
 746         client->dev.parent = &client->adapter->dev;
 747         client->dev.bus = &i2c_bus_type;
 748         client->dev.type = &i2c_client_type;
 749         client->dev.of_node = info->of_node;
 750         client->dev.fwnode = info->fwnode;
 751
 752         i2c_dev_set_name(adap, client, info);
 753
 754         if (info->properties) {
 755                 status = device_add_properties(&client->dev, info->properties);
 756                 if (status) {
 757                         dev_err(&adap->dev,
 758                                 "Failed to add properties to client %s: %d\n",
 759                                 client->name, status);
 760                         goto out_err;
 761                 }
 762         }
 763
 764         status = device_register(&client->dev);
 765         if (status)
 766                 goto out_free_props;
 767
 768         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 769                 client->name, dev_name(&client->dev));
 770
 771         return client;
 772
 773 out_free_props:
 774         if (info->properties)
 775                 device_remove_properties(&client->dev);
 776 out_err:
 777         dev_err(&adap->dev,
 778                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 779                 client->name, client->addr, status);
 780 out_err_silent:
 781         kfree(client);
 782         return NULL;
 783 }
 784 EXPORT_SYMBOL_GPL(i2c_new_device);
 785
 786
 787 /**
 788  * i2c_unregister_device - reverse effect of i2c_new_device()
 789  * @client: value returned from i2c_new_device()
 790  * Context: can sleep
 791  */
 792 void i2c_unregister_device(struct i2c_client *client)
 793 {
 794         if (!client)
 795                 return;
 796
 797         if (client->dev.of_node) {
 798                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 799                 of_node_put(client->dev.of_node);
 800         }
 801
 802         if (ACPI_COMPANION(&client->dev))
 803                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 804         device_unregister(&client->dev);
 805 }
 806 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 807
 808
 809 static const struct i2c_device_id dummy_id[] = {
 810         { "dummy", 0 },
 811         { },
 812 };
 813
 814 static int dummy_probe(struct i2c_client *client,
 815                        const struct i2c_device_id *id)
 816 {
 817         return 0;
 818 }
 819
 820 static int dummy_remove(struct i2c_client *client)
 821 {
 822         return 0;
 823 }
 824
 825 static struct i2c_driver dummy_driver = {
 826         .driver.name    = "dummy",
 827         .probe          = dummy_probe,
 828         .remove         = dummy_remove,
 829         .id_table       = dummy_id,
 830 };
 831
 832 /**
 833  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 834  * @adapter: the adapter managing the device
 835  * @address: seven bit address to be used
 836  * Context: can sleep
 837  *
 838  * This returns an I2C client bound to the "dummy" driver, intended for use
 839  * with devices that consume multiple addresses.  Examples of such chips
 840  * include various EEPROMS (like 24c04 and 24c08 models).
 841  *
 842  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 843  * except i2c_transfer() need a client handle; the dummy will be that handle.
 844  * And second, this prevents the specified address from being bound to a
 845  * different driver.
 846  *
 847  * This returns the new i2c client, which should be saved for later use with
 848  * i2c_unregister_device(); or NULL to indicate an error.
 849  */
 850 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 851 {
 852         struct i2c_board_info info = {
 853                 I2C_BOARD_INFO("dummy", address),
 854         };
 855
 856         return i2c_new_device(adapter, &info);
 857 }
 858 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 859
 860 /**
 861  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 862  * and create the associated device
 863  * @client: Handle to the primary client
 864  * @name: Handle to specify which secondary address to get
 865  * @default_addr: Used as a fallback if no secondary address was specified
 866  * Context: can sleep
 867  *
 868  * I2C clients can be composed of multiple I2C slaves bound together in a single
 869  * component. The I2C client driver then binds to the master I2C slave and needs
 870  * to create I2C dummy clients to communicate with all the other slaves.
 871  *
 872  * This function creates and returns an I2C dummy client whose I2C address is
 873  * retrieved from the platform firmware based on the given slave name. If no
 874  * address is specified by the firmware default_addr is used.
 875  *
 876  * On DT-based platforms the address is retrieved from the "reg" property entry
 877  * cell whose "reg-names" value matches the slave name.
 878  *
 879  * This returns the new i2c client, which should be saved for later use with
 880  * i2c_unregister_device(); or NULL to indicate an error.
 881  */
 882 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 883                                                 const char *name,
 884                                                 u16 default_addr)
 885 {
 886         struct device_node *np = client->dev.of_node;
 887         u32 addr = default_addr;
 888         int i;
 889
 890         if (np) {
 891                 i = of_property_match_string(np, "reg-names", name);
 892                 if (i >= 0)
 893                         of_property_read_u32_index(np, "reg", i, &addr);
 894         }
 895
 896         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 897         return i2c_new_dummy(client->adapter, addr);
 898 }
 899 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 900
 901 /* ------------------------------------------------------------------------- */
 902
 903 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 904
 905 static void i2c_adapter_dev_release(struct device *dev)
 906 {
 907         struct i2c_adapter *adap = to_i2c_adapter(dev);
 908         complete(&adap->dev_released);
 909 }
 910
 911 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 912 {
 913         unsigned int depth = 0;
 914
 915         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 916                 depth++;
 917
 918         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 919                   "adapter depth exceeds lockdep subclass limit\n");
 920
 921         return depth;
 922 }
 923 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 924
 925 /*
 926  * Let users instantiate I2C devices through sysfs. This can be used when
 927  * platform initialization code doesn't contain the proper data for
 928  * whatever reason. Also useful for drivers that do device detection and
 929  * detection fails, either because the device uses an unexpected address,
 930  * or this is a compatible device with different ID register values.
 931  *
 932  * Parameter checking may look overzealous, but we really don't want
 933  * the user to provide incorrect parameters.
 934  */
 935 static ssize_t
 936 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 937                      const char *buf, size_t count)
 938 {
 939         struct i2c_adapter *adap = to_i2c_adapter(dev);
 940         struct i2c_board_info info;
 941         struct i2c_client *client;
 942         char *blank, end;
 943         int res;
 944
 945         memset(&info, 0, sizeof(struct i2c_board_info));
 946
 947         blank = strchr(buf, ' ');
 948         if (!blank) {
 949                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 950                 return -EINVAL;
 951         }
 952         if (blank - buf > I2C_NAME_SIZE - 1) {
 953                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 954                 return -EINVAL;
 955         }
 956         memcpy(info.type, buf, blank - buf);
 957
 958         /* Parse remaining parameters, reject extra parameters */
 959         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 960         if (res < 1) {
 961                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 962                 return -EINVAL;
 963         }
 964         if (res > 1  && end != '\n') {
 965                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 966                 return -EINVAL;
 967         }
 968
 969         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 970                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 971                 info.flags |= I2C_CLIENT_TEN;
 972         }
 973
 974         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 975                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 976                 info.flags |= I2C_CLIENT_SLAVE;
 977         }
 978
 979         client = i2c_new_device(adap, &info);
 980         if (!client)
 981                 return -EINVAL;
 982
 983         /* Keep track of the added device */
 984         mutex_lock(&adap->userspace_clients_lock);
 985         list_add_tail(&client->detected, &adap->userspace_clients);
 986         mutex_unlock(&adap->userspace_clients_lock);
 987         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 988                  info.type, info.addr);
 989
 990         return count;
 991 }
 992 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
 993
 994 /*
 995  * And of course let the users delete the devices they instantiated, if
 996  * they got it wrong. This interface can only be used to delete devices
 997  * instantiated by i2c_sysfs_new_device above. This guarantees that we
 998  * don't delete devices to which some kernel code still has references.
 999  *
1000  * Parameter checking may look overzealous, but we really don't want
1001  * the user to delete the wrong device.
1002  */
1003 static ssize_t
1004 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1005                         const char *buf, size_t count)
1006 {
1007         struct i2c_adapter *adap = to_i2c_adapter(dev);
1008         struct i2c_client *client, *next;
1009         unsigned short addr;
1010         char end;
1011         int res;
1012
1013         /* Parse parameters, reject extra parameters */
1014         res = sscanf(buf, "%hi%c", &addr, &end);
1015         if (res < 1) {
1016                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1017                 return -EINVAL;
1018         }
1019         if (res > 1  && end != '\n') {
1020                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1021                 return -EINVAL;
1022         }
1023
1024         /* Make sure the device was added through sysfs */
1025         res = -ENOENT;
1026         mutex_lock_nested(&adap->userspace_clients_lock,
1027                           i2c_adapter_depth(adap));
1028         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1029                                  detected) {
1030                 if (i2c_encode_flags_to_addr(client) == addr) {
1031                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1032                                  "delete_device", client->name, client->addr);
1033
1034                         list_del(&client->detected);
1035                         i2c_unregister_device(client);
1036                         res = count;
1037                         break;
1038                 }
1039         }
1040         mutex_unlock(&adap->userspace_clients_lock);
1041
1042         if (res < 0)
1043                 dev_err(dev, "%s: Can't find device in list\n",
1044                         "delete_device");
1045         return res;
1046 }
1047 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1048                                    i2c_sysfs_delete_device);
1049
1050 static struct attribute *i2c_adapter_attrs[] = {
1051         &dev_attr_name.attr,
1052         &dev_attr_new_device.attr,
1053         &dev_attr_delete_device.attr,
1054         NULL
1055 };
1056 ATTRIBUTE_GROUPS(i2c_adapter);
1057
1058 struct device_type i2c_adapter_type = {
1059         .groups         = i2c_adapter_groups,
1060         .release        = i2c_adapter_dev_release,
1061 };
1062 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1063
1064 /**
1065  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1066  * @dev: device, probably from some driver model iterator
1067  *
1068  * When traversing the driver model tree, perhaps using driver model
1069  * iterators like @device_for_each_child(), you can't assume very much
1070  * about the nodes you find.  Use this function to avoid oopses caused
1071  * by wrongly treating some non-I2C device as an i2c_adapter.
1072  */
1073 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1074 {
1075         return (dev->type == &i2c_adapter_type)
1076                         ? to_i2c_adapter(dev)
1077                         : NULL;
1078 }
1079 EXPORT_SYMBOL(i2c_verify_adapter);
1080
1081 #ifdef CONFIG_I2C_COMPAT
1082 static struct class_compat *i2c_adapter_compat_class;
1083 #endif
1084
1085 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1086 {
1087         struct i2c_devinfo      *devinfo;
1088
1089         down_read(&__i2c_board_lock);
1090         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1091                 if (devinfo->busnum == adapter->nr
1092                                 && !i2c_new_device(adapter,
1093                                                 &devinfo->board_info))
1094                         dev_err(&adapter->dev,
1095                                 "Can't create device at 0x%02x\n",
1096                                 devinfo->board_info.addr);
1097         }
1098         up_read(&__i2c_board_lock);
1099 }
1100
1101 static int i2c_do_add_adapter(struct i2c_driver *driver,
1102                               struct i2c_adapter *adap)
1103 {
1104         /* Detect supported devices on that bus, and instantiate them */
1105         i2c_detect(adap, driver);
1106
1107         /* Let legacy drivers scan this bus for matching devices */
1108         if (driver->attach_adapter) {
1109                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1110                          driver->driver.name);
1111                 dev_warn(&adap->dev,
1112                          "Please use another way to instantiate your i2c_client\n");
1113                 /* We ignore the return code; if it fails, too bad */
1114                 driver->attach_adapter(adap);
1115         }
1116         return 0;
1117 }
1118
1119 static int __process_new_adapter(struct device_driver *d, void *data)
1120 {
1121         return i2c_do_add_adapter(to_i2c_driver(d), data);
1122 }
1123
1124 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1125         .lock_bus =    i2c_adapter_lock_bus,
1126         .trylock_bus = i2c_adapter_trylock_bus,
1127         .unlock_bus =  i2c_adapter_unlock_bus,
1128 };
1129
1130 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1131 {
1132         struct irq_domain *domain = adap->host_notify_domain;
1133         irq_hw_number_t hwirq;
1134
1135         if (!domain)
1136                 return;
1137
1138         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1139                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1140
1141         irq_domain_remove(domain);
1142         adap->host_notify_domain = NULL;
1143 }
1144
1145 static int i2c_host_notify_irq_map(struct irq_domain *h,
1146                                           unsigned int virq,
1147                                           irq_hw_number_t hw_irq_num)
1148 {
1149         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1150
1151         return 0;
1152 }
1153
1154 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1155         .map = i2c_host_notify_irq_map,
1156 };
1157
1158 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1159 {
1160         struct irq_domain *domain;
1161
1162         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1163                 return 0;
1164
1165         domain = irq_domain_create_linear(adap->dev.fwnode,
1166                                           I2C_ADDR_7BITS_COUNT,
1167                                           &i2c_host_notify_irq_ops, adap);
1168         if (!domain)
1169                 return -ENOMEM;
1170
1171         adap->host_notify_domain = domain;
1172
1173         return 0;
1174 }
1175
1176 /**
1177  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1178  * I2C client.
1179  * @adap: the adapter
1180  * @addr: the I2C address of the notifying device
1181  * Context: can't sleep
1182  *
1183  * Helper function to be called from an I2C bus driver's interrupt
1184  * handler. It will schedule the Host Notify IRQ.
1185  */
1186 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1187 {
1188         int irq;
1189
1190         if (!adap)
1191                 return -EINVAL;
1192
1193         irq = irq_find_mapping(adap->host_notify_domain, addr);
1194         if (irq <= 0)
1195                 return -ENXIO;
1196
1197         generic_handle_irq(irq);
1198
1199         return 0;
1200 }
1201 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1202
1203 static int i2c_register_adapter(struct i2c_adapter *adap)
1204 {
1205         int res = -EINVAL;
1206
1207         /* Can't register until after driver model init */
1208         if (WARN_ON(!is_registered)) {
1209                 res = -EAGAIN;
1210                 goto out_list;
1211         }
1212
1213         /* Sanity checks */
1214         if (WARN(!adap->name[0], "i2c adapter has no name"))
1215                 goto out_list;
1216
1217         if (!adap->algo) {
1218                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1219                 goto out_list;
1220         }
1221
1222         if (!adap->lock_ops)
1223                 adap->lock_ops = &i2c_adapter_lock_ops;
1224
1225         rt_mutex_init(&adap->bus_lock);
1226         rt_mutex_init(&adap->mux_lock);
1227         mutex_init(&adap->userspace_clients_lock);
1228         INIT_LIST_HEAD(&adap->userspace_clients);
1229
1230         /* Set default timeout to 1 second if not already set */
1231         if (adap->timeout == 0)
1232                 adap->timeout = HZ;
1233
1234         /* register soft irqs for Host Notify */
1235         res = i2c_setup_host_notify_irq_domain(adap);
1236         if (res) {
1237                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1238                        adap->name, res);
1239                 goto out_list;
1240         }
1241
1242         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1243         adap->dev.bus = &i2c_bus_type;
1244         adap->dev.type = &i2c_adapter_type;
1245         res = device_register(&adap->dev);
1246         if (res) {
1247                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1248                 goto out_list;
1249         }
1250
1251         res = of_i2c_setup_smbus_alert(adap);
1252         if (res)
1253                 goto out_reg;
1254
1255         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1256
1257         pm_runtime_no_callbacks(&adap->dev);
1258         pm_suspend_ignore_children(&adap->dev, true);
1259         pm_runtime_enable(&adap->dev);
1260
1261 #ifdef CONFIG_I2C_COMPAT
1262         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1263                                        adap->dev.parent);
1264         if (res)
1265                 dev_warn(&adap->dev,
1266                          "Failed to create compatibility class link\n");
1267 #endif
1268
1269         i2c_init_recovery(adap);
1270
1271         /* create pre-declared device nodes */
1272         of_i2c_register_devices(adap);
1273         i2c_acpi_register_devices(adap);
1274         i2c_acpi_install_space_handler(adap);
1275
1276         if (adap->nr < __i2c_first_dynamic_bus_num)
1277                 i2c_scan_static_board_info(adap);
1278
1279         /* Notify drivers */
1280         mutex_lock(&core_lock);
1281         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1282         mutex_unlock(&core_lock);
1283
1284         return 0;
1285
1286 out_reg:
1287         init_completion(&adap->dev_released);
1288         device_unregister(&adap->dev);
1289         wait_for_completion(&adap->dev_released);
1290 out_list:
1291         mutex_lock(&core_lock);
1292         idr_remove(&i2c_adapter_idr, adap->nr);
1293         mutex_unlock(&core_lock);
1294         return res;
1295 }
1296
1297 /**
1298  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1299  * @adap: the adapter to register (with adap->nr initialized)
1300  * Context: can sleep
1301  *
1302  * See i2c_add_numbered_adapter() for details.
1303  */
1304 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1305 {
1306         int id;
1307
1308         mutex_lock(&core_lock);
1309         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1310         mutex_unlock(&core_lock);
1311         if (WARN(id < 0, "couldn't get idr"))
1312                 return id == -ENOSPC ? -EBUSY : id;
1313
1314         return i2c_register_adapter(adap);
1315 }
1316
1317 /**
1318  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1319  * @adapter: the adapter to add
1320  * Context: can sleep
1321  *
1322  * This routine is used to declare an I2C adapter when its bus number
1323  * doesn't matter or when its bus number is specified by an dt alias.
1324  * Examples of bases when the bus number doesn't matter: I2C adapters
1325  * dynamically added by USB links or PCI plugin cards.
1326  *
1327  * When this returns zero, a new bus number was allocated and stored
1328  * in adap->nr, and the specified adapter became available for clients.
1329  * Otherwise, a negative errno value is returned.
1330  */
1331 int i2c_add_adapter(struct i2c_adapter *adapter)
1332 {
1333         struct device *dev = &adapter->dev;
1334         int id;
1335
1336         if (dev->of_node) {
1337                 id = of_alias_get_id(dev->of_node, "i2c");
1338                 if (id >= 0) {
1339                         adapter->nr = id;
1340                         return __i2c_add_numbered_adapter(adapter);
1341                 }
1342         }
1343
1344         mutex_lock(&core_lock);
1345         id = idr_alloc(&i2c_adapter_idr, adapter,
1346                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1347         mutex_unlock(&core_lock);
1348         if (WARN(id < 0, "couldn't get idr"))
1349                 return id;
1350
1351         adapter->nr = id;
1352
1353         return i2c_register_adapter(adapter);
1354 }
1355 EXPORT_SYMBOL(i2c_add_adapter);
1356
1357 /**
1358  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1359  * @adap: the adapter to register (with adap->nr initialized)
1360  * Context: can sleep
1361  *
1362  * This routine is used to declare an I2C adapter when its bus number
1363  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1364  * or otherwise built in to the system's mainboard, and where i2c_board_info
1365  * is used to properly configure I2C devices.
1366  *
1367  * If the requested bus number is set to -1, then this function will behave
1368  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1369  *
1370  * If no devices have pre-been declared for this bus, then be sure to
1371  * register the adapter before any dynamically allocated ones.  Otherwise
1372  * the required bus ID may not be available.
1373  *
1374  * When this returns zero, the specified adapter became available for
1375  * clients using the bus number provided in adap->nr.  Also, the table
1376  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1377  * and the appropriate driver model device nodes are created.  Otherwise, a
1378  * negative errno value is returned.
1379  */
1380 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1381 {
1382         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1383                 return i2c_add_adapter(adap);
1384
1385         return __i2c_add_numbered_adapter(adap);
1386 }
1387 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1388
1389 static void i2c_do_del_adapter(struct i2c_driver *driver,
1390                               struct i2c_adapter *adapter)
1391 {
1392         struct i2c_client *client, *_n;
1393
1394         /* Remove the devices we created ourselves as the result of hardware
1395          * probing (using a driver's detect method) */
1396         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1397                 if (client->adapter == adapter) {
1398                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1399                                 client->name, client->addr);
1400                         list_del(&client->detected);
1401                         i2c_unregister_device(client);
1402                 }
1403         }
1404 }
1405
1406 static int __unregister_client(struct device *dev, void *dummy)
1407 {
1408         struct i2c_client *client = i2c_verify_client(dev);
1409         if (client && strcmp(client->name, "dummy"))
1410                 i2c_unregister_device(client);
1411         return 0;
1412 }
1413
1414 static int __unregister_dummy(struct device *dev, void *dummy)
1415 {
1416         struct i2c_client *client = i2c_verify_client(dev);
1417         i2c_unregister_device(client);
1418         return 0;
1419 }
1420
1421 static int __process_removed_adapter(struct device_driver *d, void *data)
1422 {
1423         i2c_do_del_adapter(to_i2c_driver(d), data);
1424         return 0;
1425 }
1426
1427 /**
1428  * i2c_del_adapter - unregister I2C adapter
1429  * @adap: the adapter being unregistered
1430  * Context: can sleep
1431  *
1432  * This unregisters an I2C adapter which was previously registered
1433  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1434  */
1435 void i2c_del_adapter(struct i2c_adapter *adap)
1436 {
1437         struct i2c_adapter *found;
1438         struct i2c_client *client, *next;
1439
1440         /* First make sure that this adapter was ever added */
1441         mutex_lock(&core_lock);
1442         found = idr_find(&i2c_adapter_idr, adap->nr);
1443         mutex_unlock(&core_lock);
1444         if (found != adap) {
1445                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1446                 return;
1447         }
1448
1449         i2c_acpi_remove_space_handler(adap);
1450         /* Tell drivers about this removal */
1451         mutex_lock(&core_lock);
1452         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1453                                __process_removed_adapter);
1454         mutex_unlock(&core_lock);
1455
1456         /* Remove devices instantiated from sysfs */
1457         mutex_lock_nested(&adap->userspace_clients_lock,
1458                           i2c_adapter_depth(adap));
1459         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1460                                  detected) {
1461                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1462                         client->addr);
1463                 list_del(&client->detected);
1464                 i2c_unregister_device(client);
1465         }
1466         mutex_unlock(&adap->userspace_clients_lock);
1467
1468         /* Detach any active clients. This can't fail, thus we do not
1469          * check the returned value. This is a two-pass process, because
1470          * we can't remove the dummy devices during the first pass: they
1471          * could have been instantiated by real devices wishing to clean
1472          * them up properly, so we give them a chance to do that first. */
1473         device_for_each_child(&adap->dev, NULL, __unregister_client);
1474         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1475
1476 #ifdef CONFIG_I2C_COMPAT
1477         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1478                                  adap->dev.parent);
1479 #endif
1480
1481         /* device name is gone after device_unregister */
1482         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1483
1484         pm_runtime_disable(&adap->dev);
1485
1486         i2c_host_notify_irq_teardown(adap);
1487
1488         /* wait until all references to the device are gone
1489          *
1490          * FIXME: This is old code and should ideally be replaced by an
1491          * alternative which results in decoupling the lifetime of the struct
1492          * device from the i2c_adapter, like spi or netdev do. Any solution
1493          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1494          */
1495         init_completion(&adap->dev_released);
1496         device_unregister(&adap->dev);
1497         wait_for_completion(&adap->dev_released);
1498
1499         /* free bus id */
1500         mutex_lock(&core_lock);
1501         idr_remove(&i2c_adapter_idr, adap->nr);
1502         mutex_unlock(&core_lock);
1503
1504         /* Clear the device structure in case this adapter is ever going to be
1505            added again */
1506         memset(&adap->dev, 0, sizeof(adap->dev));
1507 }
1508 EXPORT_SYMBOL(i2c_del_adapter);
1509
1510 /**
1511  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1512  * @dev: The device to scan for I2C timing properties
1513  * @t: the i2c_timings struct to be filled with values
1514  * @use_defaults: bool to use sane defaults derived from the I2C specification
1515  *                when properties are not found, otherwise use 0
1516  *
1517  * Scan the device for the generic I2C properties describing timing parameters
1518  * for the signal and fill the given struct with the results. If a property was
1519  * not found and use_defaults was true, then maximum timings are assumed which
1520  * are derived from the I2C specification. If use_defaults is not used, the
1521  * results will be 0, so drivers can apply their own defaults later. The latter
1522  * is mainly intended for avoiding regressions of existing drivers which want
1523  * to switch to this function. New drivers almost always should use the defaults.
1524  */
1525
1526 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1527 {
1528         int ret;
1529
1530         memset(t, 0, sizeof(*t));
1531
1532         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1533         if (ret && use_defaults)
1534                 t->bus_freq_hz = 100000;
1535
1536         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1537         if (ret && use_defaults) {
1538                 if (t->bus_freq_hz <= 100000)
1539                         t->scl_rise_ns = 1000;
1540                 else if (t->bus_freq_hz <= 400000)
1541                         t->scl_rise_ns = 300;
1542                 else
1543                         t->scl_rise_ns = 120;
1544         }
1545
1546         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1547         if (ret && use_defaults) {
1548                 if (t->bus_freq_hz <= 400000)
1549                         t->scl_fall_ns = 300;
1550                 else
1551                         t->scl_fall_ns = 120;
1552         }
1553
1554         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1555
1556         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1557         if (ret && use_defaults)
1558                 t->sda_fall_ns = t->scl_fall_ns;
1559 }
1560 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1561
1562 /* ------------------------------------------------------------------------- */
1563
1564 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1565 {
1566         int res;
1567
1568         mutex_lock(&core_lock);
1569         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1570         mutex_unlock(&core_lock);
1571
1572         return res;
1573 }
1574 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1575
1576 static int __process_new_driver(struct device *dev, void *data)
1577 {
1578         if (dev->type != &i2c_adapter_type)
1579                 return 0;
1580         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1581 }
1582
1583 /*
1584  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1585  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1586  */
1587
1588 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1589 {
1590         int res;
1591
1592         /* Can't register until after driver model init */
1593         if (WARN_ON(!is_registered))
1594                 return -EAGAIN;
1595
1596         /* add the driver to the list of i2c drivers in the driver core */
1597         driver->driver.owner = owner;
1598         driver->driver.bus = &i2c_bus_type;
1599         INIT_LIST_HEAD(&driver->clients);
1600
1601         /* When registration returns, the driver core
1602          * will have called probe() for all matching-but-unbound devices.
1603          */
1604         res = driver_register(&driver->driver);
1605         if (res)
1606                 return res;
1607
1608         pr_debug("driver [%s] registered\n", driver->driver.name);
1609
1610         /* Walk the adapters that are already present */
1611         i2c_for_each_dev(driver, __process_new_driver);
1612
1613         return 0;
1614 }
1615 EXPORT_SYMBOL(i2c_register_driver);
1616
1617 static int __process_removed_driver(struct device *dev, void *data)
1618 {
1619         if (dev->type == &i2c_adapter_type)
1620                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1621         return 0;
1622 }
1623
1624 /**
1625  * i2c_del_driver - unregister I2C driver
1626  * @driver: the driver being unregistered
1627  * Context: can sleep
1628  */
1629 void i2c_del_driver(struct i2c_driver *driver)
1630 {
1631         i2c_for_each_dev(driver, __process_removed_driver);
1632
1633         driver_unregister(&driver->driver);
1634         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1635 }
1636 EXPORT_SYMBOL(i2c_del_driver);
1637
1638 /* ------------------------------------------------------------------------- */
1639
1640 /**
1641  * i2c_use_client - increments the reference count of the i2c client structure
1642  * @client: the client being referenced
1643  *
1644  * Each live reference to a client should be refcounted. The driver model does
1645  * that automatically as part of driver binding, so that most drivers don't
1646  * need to do this explicitly: they hold a reference until they're unbound
1647  * from the device.
1648  *
1649  * A pointer to the client with the incremented reference counter is returned.
1650  */
1651 struct i2c_client *i2c_use_client(struct i2c_client *client)
1652 {
1653         if (client && get_device(&client->dev))
1654                 return client;
1655         return NULL;
1656 }
1657 EXPORT_SYMBOL(i2c_use_client);
1658
1659 /**
1660  * i2c_release_client - release a use of the i2c client structure
1661  * @client: the client being no longer referenced
1662  *
1663  * Must be called when a user of a client is finished with it.
1664  */
1665 void i2c_release_client(struct i2c_client *client)
1666 {
1667         if (client)
1668                 put_device(&client->dev);
1669 }
1670 EXPORT_SYMBOL(i2c_release_client);
1671
1672 struct i2c_cmd_arg {
1673         unsigned        cmd;
1674         void            *arg;
1675 };
1676
1677 static int i2c_cmd(struct device *dev, void *_arg)
1678 {
1679         struct i2c_client       *client = i2c_verify_client(dev);
1680         struct i2c_cmd_arg      *arg = _arg;
1681         struct i2c_driver       *driver;
1682
1683         if (!client || !client->dev.driver)
1684                 return 0;
1685
1686         driver = to_i2c_driver(client->dev.driver);
1687         if (driver->command)
1688                 driver->command(client, arg->cmd, arg->arg);
1689         return 0;
1690 }
1691
1692 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1693 {
1694         struct i2c_cmd_arg      cmd_arg;
1695
1696         cmd_arg.cmd = cmd;
1697         cmd_arg.arg = arg;
1698         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1699 }
1700 EXPORT_SYMBOL(i2c_clients_command);
1701
1702 static int __init i2c_init(void)
1703 {
1704         int retval;
1705
1706         retval = of_alias_get_highest_id("i2c");
1707
1708         down_write(&__i2c_board_lock);
1709         if (retval >= __i2c_first_dynamic_bus_num)
1710                 __i2c_first_dynamic_bus_num = retval + 1;
1711         up_write(&__i2c_board_lock);
1712
1713         retval = bus_register(&i2c_bus_type);
1714         if (retval)
1715                 return retval;
1716
1717         is_registered = true;
1718
1719 #ifdef CONFIG_I2C_COMPAT
1720         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1721         if (!i2c_adapter_compat_class) {
1722                 retval = -ENOMEM;
1723                 goto bus_err;
1724         }
1725 #endif
1726         retval = i2c_add_driver(&dummy_driver);
1727         if (retval)
1728                 goto class_err;
1729
1730         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1731                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1732         if (IS_ENABLED(CONFIG_ACPI))
1733                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1734
1735         return 0;
1736
1737 class_err:
1738 #ifdef CONFIG_I2C_COMPAT
1739         class_compat_unregister(i2c_adapter_compat_class);
1740 bus_err:
1741 #endif
1742         is_registered = false;
1743         bus_unregister(&i2c_bus_type);
1744         return retval;
1745 }
1746
1747 static void __exit i2c_exit(void)
1748 {
1749         if (IS_ENABLED(CONFIG_ACPI))
1750                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1751         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1752                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1753         i2c_del_driver(&dummy_driver);
1754 #ifdef CONFIG_I2C_COMPAT
1755         class_compat_unregister(i2c_adapter_compat_class);
1756 #endif
1757         bus_unregister(&i2c_bus_type);
1758         tracepoint_synchronize_unregister();
1759 }
1760
1761 /* We must initialize early, because some subsystems register i2c drivers
1762  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1763  */
1764 postcore_initcall(i2c_init);
1765 module_exit(i2c_exit);
1766
1767 /* ----------------------------------------------------
1768  * the functional interface to the i2c busses.
1769  * ----------------------------------------------------
1770  */
1771
1772 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1773 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1774
1775 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1776 {
1777         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1778                             err_msg, msg->addr, msg->len,
1779                             msg->flags & I2C_M_RD ? "read" : "write");
1780         return -EOPNOTSUPP;
1781 }
1782
1783 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1784 {
1785         const struct i2c_adapter_quirks *q = adap->quirks;
1786         int max_num = q->max_num_msgs, i;
1787         bool do_len_check = true;
1788
1789         if (q->flags & I2C_AQ_COMB) {
1790                 max_num = 2;
1791
1792                 /* special checks for combined messages */
1793                 if (num == 2) {
1794                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1795                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1796
1797                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1798                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1799
1800                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1801                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1802
1803                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1804                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1805
1806                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1807                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1808
1809                         do_len_check = false;
1810                 }
1811         }
1812
1813         if (i2c_quirk_exceeded(num, max_num))
1814                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1815
1816         for (i = 0; i < num; i++) {
1817                 u16 len = msgs[i].len;
1818
1819                 if (msgs[i].flags & I2C_M_RD) {
1820                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1821                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1822                 } else {
1823                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1824                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1825                 }
1826         }
1827
1828         return 0;
1829 }
1830
1831 /**
1832  * __i2c_transfer - unlocked flavor of i2c_transfer
1833  * @adap: Handle to I2C bus
1834  * @msgs: One or more messages to execute before STOP is issued to
1835  *      terminate the operation; each message begins with a START.
1836  * @num: Number of messages to be executed.
1837  *
1838  * Returns negative errno, else the number of messages executed.
1839  *
1840  * Adapter lock must be held when calling this function. No debug logging
1841  * takes place. adap->algo->master_xfer existence isn't checked.
1842  */
1843 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1844 {
1845         unsigned long orig_jiffies;
1846         int ret, try;
1847
1848         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1849                 return -EOPNOTSUPP;
1850
1851         /*
1852          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1853          * enabled.  This is an efficient way of keeping the for-loop from
1854          * being executed when not needed.
1855          */
1856         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1857                 int i;
1858                 for (i = 0; i < num; i++)
1859                         if (msgs[i].flags & I2C_M_RD)
1860                                 trace_i2c_read(adap, &msgs[i], i);
1861                         else
1862                                 trace_i2c_write(adap, &msgs[i], i);
1863         }
1864
1865         /* Retry automatically on arbitration loss */
1866         orig_jiffies = jiffies;
1867         for (ret = 0, try = 0; try <= adap->retries; try++) {
1868                 ret = adap->algo->master_xfer(adap, msgs, num);
1869                 if (ret != -EAGAIN)
1870                         break;
1871                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1872                         break;
1873         }
1874
1875         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1876                 int i;
1877                 for (i = 0; i < ret; i++)
1878                         if (msgs[i].flags & I2C_M_RD)
1879                                 trace_i2c_reply(adap, &msgs[i], i);
1880                 trace_i2c_result(adap, num, ret);
1881         }
1882
1883         return ret;
1884 }
1885 EXPORT_SYMBOL(__i2c_transfer);
1886
1887 /**
1888  * i2c_transfer - execute a single or combined I2C message
1889  * @adap: Handle to I2C bus
1890  * @msgs: One or more messages to execute before STOP is issued to
1891  *      terminate the operation; each message begins with a START.
1892  * @num: Number of messages to be executed.
1893  *
1894  * Returns negative errno, else the number of messages executed.
1895  *
1896  * Note that there is no requirement that each message be sent to
1897  * the same slave address, although that is the most common model.
1898  */
1899 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1900 {
1901         int ret;
1902
1903         /* REVISIT the fault reporting model here is weak:
1904          *
1905          *  - When we get an error after receiving N bytes from a slave,
1906          *    there is no way to report "N".
1907          *
1908          *  - When we get a NAK after transmitting N bytes to a slave,
1909          *    there is no way to report "N" ... or to let the master
1910          *    continue executing the rest of this combined message, if
1911          *    that's the appropriate response.
1912          *
1913          *  - When for example "num" is two and we successfully complete
1914          *    the first message but get an error part way through the
1915          *    second, it's unclear whether that should be reported as
1916          *    one (discarding status on the second message) or errno
1917          *    (discarding status on the first one).
1918          */
1919
1920         if (adap->algo->master_xfer) {
1921 #ifdef DEBUG
1922                 for (ret = 0; ret < num; ret++) {
1923                         dev_dbg(&adap->dev,
1924                                 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1925                                 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1926                                 msgs[ret].addr, msgs[ret].len,
1927                                 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1928                 }
1929 #endif
1930
1931                 if (in_atomic() || irqs_disabled()) {
1932                         ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1933                         if (!ret)
1934                                 /* I2C activity is ongoing. */
1935                                 return -EAGAIN;
1936                 } else {
1937                         i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1938                 }
1939
1940                 ret = __i2c_transfer(adap, msgs, num);
1941                 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1942
1943                 return ret;
1944         } else {
1945                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1946                 return -EOPNOTSUPP;
1947         }
1948 }
1949 EXPORT_SYMBOL(i2c_transfer);
1950
1951 /**
1952  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1953  *                             to/from a buffer
1954  * @client: Handle to slave device
1955  * @buf: Where the data is stored
1956  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1957  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1958  *
1959  * Returns negative errno, or else the number of bytes transferred.
1960  */
1961 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1962                               int count, u16 flags)
1963 {
1964         int ret;
1965         struct i2c_msg msg = {
1966                 .addr = client->addr,
1967                 .flags = flags | (client->flags & I2C_M_TEN),
1968                 .len = count,
1969                 .buf = buf,
1970         };
1971
1972         ret = i2c_transfer(client->adapter, &msg, 1);
1973
1974         /*
1975          * If everything went ok (i.e. 1 msg transferred), return #bytes
1976          * transferred, else error code.
1977          */
1978         return (ret == 1) ? count : ret;
1979 }
1980 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1981
1982 /**
1983  * i2c_get_device_id - get manufacturer, part id and die revision of a device
1984  * @client: The device to query
1985  * @id: The queried information
1986  *
1987  * Returns negative errno on error, zero on success.
1988  */
1989 int i2c_get_device_id(const struct i2c_client *client,
1990                       struct i2c_device_identity *id)
1991 {
1992         struct i2c_adapter *adap = client->adapter;
1993         union i2c_smbus_data raw_id;
1994         int ret;
1995
1996         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
1997                 return -EOPNOTSUPP;
1998
1999         raw_id.block[0] = 3;
2000         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2001                              I2C_SMBUS_READ, client->addr << 1,
2002                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2003         if (ret)
2004                 return ret;
2005
2006         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2007         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2008         id->die_revision = raw_id.block[3] & 0x7;
2009         return 0;
2010 }
2011 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2012
2013 /* ----------------------------------------------------
2014  * the i2c address scanning function
2015  * Will not work for 10-bit addresses!
2016  * ----------------------------------------------------
2017  */
2018
2019 /*
2020  * Legacy default probe function, mostly relevant for SMBus. The default
2021  * probe method is a quick write, but it is known to corrupt the 24RF08
2022  * EEPROMs due to a state machine bug, and could also irreversibly
2023  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2024  * we use a short byte read instead. Also, some bus drivers don't implement
2025  * quick write, so we fallback to a byte read in that case too.
2026  * On x86, there is another special case for FSC hardware monitoring chips,
2027  * which want regular byte reads (address 0x73.) Fortunately, these are the
2028  * only known chips using this I2C address on PC hardware.
2029  * Returns 1 if probe succeeded, 0 if not.
2030  */
2031 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2032 {
2033         int err;
2034         union i2c_smbus_data dummy;
2035
2036 #ifdef CONFIG_X86
2037         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2038          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2039                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2040                                      I2C_SMBUS_BYTE_DATA, &dummy);
2041         else
2042 #endif
2043         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2044          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2045                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2046                                      I2C_SMBUS_QUICK, NULL);
2047         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2048                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2049                                      I2C_SMBUS_BYTE, &dummy);
2050         else {
2051                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2052                          addr);
2053                 err = -EOPNOTSUPP;
2054         }
2055
2056         return err >= 0;
2057 }
2058
2059 static int i2c_detect_address(struct i2c_client *temp_client,
2060                               struct i2c_driver *driver)
2061 {
2062         struct i2c_board_info info;
2063         struct i2c_adapter *adapter = temp_client->adapter;
2064         int addr = temp_client->addr;
2065         int err;
2066
2067         /* Make sure the address is valid */
2068         err = i2c_check_7bit_addr_validity_strict(addr);
2069         if (err) {
2070                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2071                          addr);
2072                 return err;
2073         }
2074
2075         /* Skip if already in use (7 bit, no need to encode flags) */
2076         if (i2c_check_addr_busy(adapter, addr))
2077                 return 0;
2078
2079         /* Make sure there is something at this address */
2080         if (!i2c_default_probe(adapter, addr))
2081                 return 0;
2082
2083         /* Finally call the custom detection function */
2084         memset(&info, 0, sizeof(struct i2c_board_info));
2085         info.addr = addr;
2086         err = driver->detect(temp_client, &info);
2087         if (err) {
2088                 /* -ENODEV is returned if the detection fails. We catch it
2089                    here as this isn't an error. */
2090                 return err == -ENODEV ? 0 : err;
2091         }
2092
2093         /* Consistency check */
2094         if (info.type[0] == '\0') {
2095                 dev_err(&adapter->dev,
2096                         "%s detection function provided no name for 0x%x\n",
2097                         driver->driver.name, addr);
2098         } else {
2099                 struct i2c_client *client;
2100
2101                 /* Detection succeeded, instantiate the device */
2102                 if (adapter->class & I2C_CLASS_DEPRECATED)
2103                         dev_warn(&adapter->dev,
2104                                 "This adapter will soon drop class based instantiation of devices. "
2105                                 "Please make sure client 0x%02x gets instantiated by other means. "
2106                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2107                                 info.addr);
2108
2109                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2110                         info.type, info.addr);
2111                 client = i2c_new_device(adapter, &info);
2112                 if (client)
2113                         list_add_tail(&client->detected, &driver->clients);
2114                 else
2115                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2116                                 info.type, info.addr);
2117         }
2118         return 0;
2119 }
2120
2121 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2122 {
2123         const unsigned short *address_list;
2124         struct i2c_client *temp_client;
2125         int i, err = 0;
2126         int adap_id = i2c_adapter_id(adapter);
2127
2128         address_list = driver->address_list;
2129         if (!driver->detect || !address_list)
2130                 return 0;
2131
2132         /* Warn that the adapter lost class based instantiation */
2133         if (adapter->class == I2C_CLASS_DEPRECATED) {
2134                 dev_dbg(&adapter->dev,
2135                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2136                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2137                         driver->driver.name);
2138                 return 0;
2139         }
2140
2141         /* Stop here if the classes do not match */
2142         if (!(adapter->class & driver->class))
2143                 return 0;
2144
2145         /* Set up a temporary client to help detect callback */
2146         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2147         if (!temp_client)
2148                 return -ENOMEM;
2149         temp_client->adapter = adapter;
2150
2151         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2152                 dev_dbg(&adapter->dev,
2153                         "found normal entry for adapter %d, addr 0x%02x\n",
2154                         adap_id, address_list[i]);
2155                 temp_client->addr = address_list[i];
2156                 err = i2c_detect_address(temp_client, driver);
2157                 if (unlikely(err))
2158                         break;
2159         }
2160
2161         kfree(temp_client);
2162         return err;
2163 }
2164
2165 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2166 {
2167         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2168                               I2C_SMBUS_QUICK, NULL) >= 0;
2169 }
2170 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2171
2172 struct i2c_client *
2173 i2c_new_probed_device(struct i2c_adapter *adap,
2174                       struct i2c_board_info *info,
2175                       unsigned short const *addr_list,
2176                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2177 {
2178         int i;
2179
2180         if (!probe)
2181                 probe = i2c_default_probe;
2182
2183         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2184                 /* Check address validity */
2185                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2186                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2187                                  addr_list[i]);
2188                         continue;
2189                 }
2190
2191                 /* Check address availability (7 bit, no need to encode flags) */
2192                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2193                         dev_dbg(&adap->dev,
2194                                 "Address 0x%02x already in use, not probing\n",
2195                                 addr_list[i]);
2196                         continue;
2197                 }
2198
2199                 /* Test address responsiveness */
2200                 if (probe(adap, addr_list[i]))
2201                         break;
2202         }
2203
2204         if (addr_list[i] == I2C_CLIENT_END) {
2205                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2206                 return NULL;
2207         }
2208
2209         info->addr = addr_list[i];
2210         return i2c_new_device(adap, info);
2211 }
2212 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2213
2214 struct i2c_adapter *i2c_get_adapter(int nr)
2215 {
2216         struct i2c_adapter *adapter;
2217
2218         mutex_lock(&core_lock);
2219         adapter = idr_find(&i2c_adapter_idr, nr);
2220         if (!adapter)
2221                 goto exit;
2222
2223         if (try_module_get(adapter->owner))
2224                 get_device(&adapter->dev);
2225         else
2226                 adapter = NULL;
2227
2228  exit:
2229         mutex_unlock(&core_lock);
2230         return adapter;
2231 }
2232 EXPORT_SYMBOL(i2c_get_adapter);
2233
2234 void i2c_put_adapter(struct i2c_adapter *adap)
2235 {
2236         if (!adap)
2237                 return;
2238
2239         put_device(&adap->dev);
2240         module_put(adap->owner);
2241 }
2242 EXPORT_SYMBOL(i2c_put_adapter);
2243
2244 /**
2245  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2246  * @msg: the message to be checked
2247  * @threshold: the minimum number of bytes for which using DMA makes sense
2248  *
2249  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2250  *         Or a valid pointer to be used with DMA. After use, release it by
2251  *         calling i2c_release_dma_safe_msg_buf().
2252  *
2253  * This function must only be called from process context!
2254  */
2255 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2256 {
2257         if (msg->len < threshold)
2258                 return NULL;
2259
2260         if (msg->flags & I2C_M_DMA_SAFE)
2261                 return msg->buf;
2262
2263         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2264                  msg->addr, msg->len);
2265
2266         if (msg->flags & I2C_M_RD)
2267                 return kzalloc(msg->len, GFP_KERNEL);
2268         else
2269                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2270 }
2271 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2272
2273 /**
2274  * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2275  * @msg: the message to be synced with
2276  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2277  */
2278 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2279 {
2280         if (!buf || buf == msg->buf)
2281                 return;
2282
2283         if (msg->flags & I2C_M_RD)
2284                 memcpy(msg->buf, buf, msg->len);
2285
2286         kfree(buf);
2287 }
2288 EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2289
2290 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2291 MODULE_DESCRIPTION("I2C-Bus main module");
2292 MODULE_LICENSE("GPL");