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)
 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         client->flags = info->flags;
 721         client->addr = info->addr;
 722
 723         client->irq = info->irq;
 724         if (!client->irq)
 725                 client->irq = i2c_dev_irq_from_resources(info->resources,
 726                                                          info->num_resources);
 727
 728         strlcpy(client->name, info->type, sizeof(client->name));
 729
 730         status = i2c_check_addr_validity(client->addr, client->flags);
 731         if (status) {
 732                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 733                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 734                 goto out_err_silent;
 735         }
 736
 737         /* Check for address business */
 738         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 739         if (status)
 740                 goto out_err;
 741
 742         client->dev.parent = &client->adapter->dev;
 743         client->dev.bus = &i2c_bus_type;
 744         client->dev.type = &i2c_client_type;
 745         client->dev.of_node = of_node_get(info->of_node);
 746         client->dev.fwnode = info->fwnode;
 747
 748         i2c_dev_set_name(adap, client, info);
 749
 750         if (info->properties) {
 751                 status = device_add_properties(&client->dev, info->properties);
 752                 if (status) {
 753                         dev_err(&adap->dev,
 754                                 "Failed to add properties to client %s: %d\n",
 755                                 client->name, status);
 756                         goto out_err_put_of_node;
 757                 }
 758         }
 759
 760         status = device_register(&client->dev);
 761         if (status)
 762                 goto out_free_props;
 763
 764         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 765                 client->name, dev_name(&client->dev));
 766
 767         return client;
 768
 769 out_free_props:
 770         if (info->properties)
 771                 device_remove_properties(&client->dev);
 772 out_err_put_of_node:
 773         of_node_put(info->of_node);
 774 out_err:
 775         dev_err(&adap->dev,
 776                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 777                 client->name, client->addr, status);
 778 out_err_silent:
 779         kfree(client);
 780         return NULL;
 781 }
 782 EXPORT_SYMBOL_GPL(i2c_new_device);
 783
 784
 785 /**
 786  * i2c_unregister_device - reverse effect of i2c_new_device()
 787  * @client: value returned from i2c_new_device()
 788  * Context: can sleep
 789  */
 790 void i2c_unregister_device(struct i2c_client *client)
 791 {
 792         if (!client)
 793                 return;
 794
 795         if (client->dev.of_node) {
 796                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 797                 of_node_put(client->dev.of_node);
 798         }
 799
 800         if (ACPI_COMPANION(&client->dev))
 801                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 802         device_unregister(&client->dev);
 803 }
 804 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 805
 806
 807 static const struct i2c_device_id dummy_id[] = {
 808         { "dummy", 0 },
 809         { },
 810 };
 811
 812 static int dummy_probe(struct i2c_client *client,
 813                        const struct i2c_device_id *id)
 814 {
 815         return 0;
 816 }
 817
 818 static int dummy_remove(struct i2c_client *client)
 819 {
 820         return 0;
 821 }
 822
 823 static struct i2c_driver dummy_driver = {
 824         .driver.name    = "dummy",
 825         .probe          = dummy_probe,
 826         .remove         = dummy_remove,
 827         .id_table       = dummy_id,
 828 };
 829
 830 /**
 831  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 832  * @adapter: the adapter managing the device
 833  * @address: seven bit address to be used
 834  * Context: can sleep
 835  *
 836  * This returns an I2C client bound to the "dummy" driver, intended for use
 837  * with devices that consume multiple addresses.  Examples of such chips
 838  * include various EEPROMS (like 24c04 and 24c08 models).
 839  *
 840  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 841  * except i2c_transfer() need a client handle; the dummy will be that handle.
 842  * And second, this prevents the specified address from being bound to a
 843  * different driver.
 844  *
 845  * This returns the new i2c client, which should be saved for later use with
 846  * i2c_unregister_device(); or NULL to indicate an error.
 847  */
 848 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 849 {
 850         struct i2c_board_info info = {
 851                 I2C_BOARD_INFO("dummy", address),
 852         };
 853
 854         return i2c_new_device(adapter, &info);
 855 }
 856 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 857
 858 /**
 859  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 860  * and create the associated device
 861  * @client: Handle to the primary client
 862  * @name: Handle to specify which secondary address to get
 863  * @default_addr: Used as a fallback if no secondary address was specified
 864  * Context: can sleep
 865  *
 866  * I2C clients can be composed of multiple I2C slaves bound together in a single
 867  * component. The I2C client driver then binds to the master I2C slave and needs
 868  * to create I2C dummy clients to communicate with all the other slaves.
 869  *
 870  * This function creates and returns an I2C dummy client whose I2C address is
 871  * retrieved from the platform firmware based on the given slave name. If no
 872  * address is specified by the firmware default_addr is used.
 873  *
 874  * On DT-based platforms the address is retrieved from the "reg" property entry
 875  * cell whose "reg-names" value matches the slave name.
 876  *
 877  * This returns the new i2c client, which should be saved for later use with
 878  * i2c_unregister_device(); or NULL to indicate an error.
 879  */
 880 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 881                                                 const char *name,
 882                                                 u16 default_addr)
 883 {
 884         struct device_node *np = client->dev.of_node;
 885         u32 addr = default_addr;
 886         int i;
 887
 888         if (np) {
 889                 i = of_property_match_string(np, "reg-names", name);
 890                 if (i >= 0)
 891                         of_property_read_u32_index(np, "reg", i, &addr);
 892         }
 893
 894         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 895         return i2c_new_dummy(client->adapter, addr);
 896 }
 897 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 898
 899 /* ------------------------------------------------------------------------- */
 900
 901 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 902
 903 static void i2c_adapter_dev_release(struct device *dev)
 904 {
 905         struct i2c_adapter *adap = to_i2c_adapter(dev);
 906         complete(&adap->dev_released);
 907 }
 908
 909 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 910 {
 911         unsigned int depth = 0;
 912
 913         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 914                 depth++;
 915
 916         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 917                   "adapter depth exceeds lockdep subclass limit\n");
 918
 919         return depth;
 920 }
 921 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 922
 923 /*
 924  * Let users instantiate I2C devices through sysfs. This can be used when
 925  * platform initialization code doesn't contain the proper data for
 926  * whatever reason. Also useful for drivers that do device detection and
 927  * detection fails, either because the device uses an unexpected address,
 928  * or this is a compatible device with different ID register values.
 929  *
 930  * Parameter checking may look overzealous, but we really don't want
 931  * the user to provide incorrect parameters.
 932  */
 933 static ssize_t
 934 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 935                      const char *buf, size_t count)
 936 {
 937         struct i2c_adapter *adap = to_i2c_adapter(dev);
 938         struct i2c_board_info info;
 939         struct i2c_client *client;
 940         char *blank, end;
 941         int res;
 942
 943         memset(&info, 0, sizeof(struct i2c_board_info));
 944
 945         blank = strchr(buf, ' ');
 946         if (!blank) {
 947                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 948                 return -EINVAL;
 949         }
 950         if (blank - buf > I2C_NAME_SIZE - 1) {
 951                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 952                 return -EINVAL;
 953         }
 954         memcpy(info.type, buf, blank - buf);
 955
 956         /* Parse remaining parameters, reject extra parameters */
 957         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 958         if (res < 1) {
 959                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 960                 return -EINVAL;
 961         }
 962         if (res > 1  && end != '\n') {
 963                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 964                 return -EINVAL;
 965         }
 966
 967         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 968                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 969                 info.flags |= I2C_CLIENT_TEN;
 970         }
 971
 972         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 973                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 974                 info.flags |= I2C_CLIENT_SLAVE;
 975         }
 976
 977         client = i2c_new_device(adap, &info);
 978         if (!client)
 979                 return -EINVAL;
 980
 981         /* Keep track of the added device */
 982         mutex_lock(&adap->userspace_clients_lock);
 983         list_add_tail(&client->detected, &adap->userspace_clients);
 984         mutex_unlock(&adap->userspace_clients_lock);
 985         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 986                  info.type, info.addr);
 987
 988         return count;
 989 }
 990 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
 991
 992 /*
 993  * And of course let the users delete the devices they instantiated, if
 994  * they got it wrong. This interface can only be used to delete devices
 995  * instantiated by i2c_sysfs_new_device above. This guarantees that we
 996  * don't delete devices to which some kernel code still has references.
 997  *
 998  * Parameter checking may look overzealous, but we really don't want
 999  * the user to delete the wrong device.
1000  */
1001 static ssize_t
1002 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1003                         const char *buf, size_t count)
1004 {
1005         struct i2c_adapter *adap = to_i2c_adapter(dev);
1006         struct i2c_client *client, *next;
1007         unsigned short addr;
1008         char end;
1009         int res;
1010
1011         /* Parse parameters, reject extra parameters */
1012         res = sscanf(buf, "%hi%c", &addr, &end);
1013         if (res < 1) {
1014                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1015                 return -EINVAL;
1016         }
1017         if (res > 1  && end != '\n') {
1018                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1019                 return -EINVAL;
1020         }
1021
1022         /* Make sure the device was added through sysfs */
1023         res = -ENOENT;
1024         mutex_lock_nested(&adap->userspace_clients_lock,
1025                           i2c_adapter_depth(adap));
1026         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1027                                  detected) {
1028                 if (i2c_encode_flags_to_addr(client) == addr) {
1029                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1030                                  "delete_device", client->name, client->addr);
1031
1032                         list_del(&client->detected);
1033                         i2c_unregister_device(client);
1034                         res = count;
1035                         break;
1036                 }
1037         }
1038         mutex_unlock(&adap->userspace_clients_lock);
1039
1040         if (res < 0)
1041                 dev_err(dev, "%s: Can't find device in list\n",
1042                         "delete_device");
1043         return res;
1044 }
1045 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1046                                    i2c_sysfs_delete_device);
1047
1048 static struct attribute *i2c_adapter_attrs[] = {
1049         &dev_attr_name.attr,
1050         &dev_attr_new_device.attr,
1051         &dev_attr_delete_device.attr,
1052         NULL
1053 };
1054 ATTRIBUTE_GROUPS(i2c_adapter);
1055
1056 struct device_type i2c_adapter_type = {
1057         .groups         = i2c_adapter_groups,
1058         .release        = i2c_adapter_dev_release,
1059 };
1060 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1061
1062 /**
1063  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1064  * @dev: device, probably from some driver model iterator
1065  *
1066  * When traversing the driver model tree, perhaps using driver model
1067  * iterators like @device_for_each_child(), you can't assume very much
1068  * about the nodes you find.  Use this function to avoid oopses caused
1069  * by wrongly treating some non-I2C device as an i2c_adapter.
1070  */
1071 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1072 {
1073         return (dev->type == &i2c_adapter_type)
1074                         ? to_i2c_adapter(dev)
1075                         : NULL;
1076 }
1077 EXPORT_SYMBOL(i2c_verify_adapter);
1078
1079 #ifdef CONFIG_I2C_COMPAT
1080 static struct class_compat *i2c_adapter_compat_class;
1081 #endif
1082
1083 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1084 {
1085         struct i2c_devinfo      *devinfo;
1086
1087         down_read(&__i2c_board_lock);
1088         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1089                 if (devinfo->busnum == adapter->nr
1090                                 && !i2c_new_device(adapter,
1091                                                 &devinfo->board_info))
1092                         dev_err(&adapter->dev,
1093                                 "Can't create device at 0x%02x\n",
1094                                 devinfo->board_info.addr);
1095         }
1096         up_read(&__i2c_board_lock);
1097 }
1098
1099 static int i2c_do_add_adapter(struct i2c_driver *driver,
1100                               struct i2c_adapter *adap)
1101 {
1102         /* Detect supported devices on that bus, and instantiate them */
1103         i2c_detect(adap, driver);
1104
1105         /* Let legacy drivers scan this bus for matching devices */
1106         if (driver->attach_adapter) {
1107                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1108                          driver->driver.name);
1109                 dev_warn(&adap->dev,
1110                          "Please use another way to instantiate your i2c_client\n");
1111                 /* We ignore the return code; if it fails, too bad */
1112                 driver->attach_adapter(adap);
1113         }
1114         return 0;
1115 }
1116
1117 static int __process_new_adapter(struct device_driver *d, void *data)
1118 {
1119         return i2c_do_add_adapter(to_i2c_driver(d), data);
1120 }
1121
1122 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1123         .lock_bus =    i2c_adapter_lock_bus,
1124         .trylock_bus = i2c_adapter_trylock_bus,
1125         .unlock_bus =  i2c_adapter_unlock_bus,
1126 };
1127
1128 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1129 {
1130         struct irq_domain *domain = adap->host_notify_domain;
1131         irq_hw_number_t hwirq;
1132
1133         if (!domain)
1134                 return;
1135
1136         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1137                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1138
1139         irq_domain_remove(domain);
1140         adap->host_notify_domain = NULL;
1141 }
1142
1143 static int i2c_host_notify_irq_map(struct irq_domain *h,
1144                                           unsigned int virq,
1145                                           irq_hw_number_t hw_irq_num)
1146 {
1147         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1148
1149         return 0;
1150 }
1151
1152 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1153         .map = i2c_host_notify_irq_map,
1154 };
1155
1156 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1157 {
1158         struct irq_domain *domain;
1159
1160         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1161                 return 0;
1162
1163         domain = irq_domain_create_linear(adap->dev.fwnode,
1164                                           I2C_ADDR_7BITS_COUNT,
1165                                           &i2c_host_notify_irq_ops, adap);
1166         if (!domain)
1167                 return -ENOMEM;
1168
1169         adap->host_notify_domain = domain;
1170
1171         return 0;
1172 }
1173
1174 /**
1175  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1176  * I2C client.
1177  * @adap: the adapter
1178  * @addr: the I2C address of the notifying device
1179  * Context: can't sleep
1180  *
1181  * Helper function to be called from an I2C bus driver's interrupt
1182  * handler. It will schedule the Host Notify IRQ.
1183  */
1184 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1185 {
1186         int irq;
1187
1188         if (!adap)
1189                 return -EINVAL;
1190
1191         irq = irq_find_mapping(adap->host_notify_domain, addr);
1192         if (irq <= 0)
1193                 return -ENXIO;
1194
1195         generic_handle_irq(irq);
1196
1197         return 0;
1198 }
1199 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1200
1201 static int i2c_register_adapter(struct i2c_adapter *adap)
1202 {
1203         int res = -EINVAL;
1204
1205         /* Can't register until after driver model init */
1206         if (WARN_ON(!is_registered)) {
1207                 res = -EAGAIN;
1208                 goto out_list;
1209         }
1210
1211         /* Sanity checks */
1212         if (WARN(!adap->name[0], "i2c adapter has no name"))
1213                 goto out_list;
1214
1215         if (!adap->algo) {
1216                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1217                 goto out_list;
1218         }
1219
1220         if (!adap->lock_ops)
1221                 adap->lock_ops = &i2c_adapter_lock_ops;
1222
1223         rt_mutex_init(&adap->bus_lock);
1224         rt_mutex_init(&adap->mux_lock);
1225         mutex_init(&adap->userspace_clients_lock);
1226         INIT_LIST_HEAD(&adap->userspace_clients);
1227
1228         /* Set default timeout to 1 second if not already set */
1229         if (adap->timeout == 0)
1230                 adap->timeout = HZ;
1231
1232         /* register soft irqs for Host Notify */
1233         res = i2c_setup_host_notify_irq_domain(adap);
1234         if (res) {
1235                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1236                        adap->name, res);
1237                 goto out_list;
1238         }
1239
1240         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1241         adap->dev.bus = &i2c_bus_type;
1242         adap->dev.type = &i2c_adapter_type;
1243         res = device_register(&adap->dev);
1244         if (res) {
1245                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1246                 goto out_list;
1247         }
1248
1249         res = of_i2c_setup_smbus_alert(adap);
1250         if (res)
1251                 goto out_reg;
1252
1253         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1254
1255         pm_runtime_no_callbacks(&adap->dev);
1256         pm_suspend_ignore_children(&adap->dev, true);
1257         pm_runtime_enable(&adap->dev);
1258
1259 #ifdef CONFIG_I2C_COMPAT
1260         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1261                                        adap->dev.parent);
1262         if (res)
1263                 dev_warn(&adap->dev,
1264                          "Failed to create compatibility class link\n");
1265 #endif
1266
1267         i2c_init_recovery(adap);
1268
1269         /* create pre-declared device nodes */
1270         of_i2c_register_devices(adap);
1271         i2c_acpi_register_devices(adap);
1272         i2c_acpi_install_space_handler(adap);
1273
1274         if (adap->nr < __i2c_first_dynamic_bus_num)
1275                 i2c_scan_static_board_info(adap);
1276
1277         /* Notify drivers */
1278         mutex_lock(&core_lock);
1279         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1280         mutex_unlock(&core_lock);
1281
1282         return 0;
1283
1284 out_reg:
1285         init_completion(&adap->dev_released);
1286         device_unregister(&adap->dev);
1287         wait_for_completion(&adap->dev_released);
1288 out_list:
1289         mutex_lock(&core_lock);
1290         idr_remove(&i2c_adapter_idr, adap->nr);
1291         mutex_unlock(&core_lock);
1292         return res;
1293 }
1294
1295 /**
1296  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1297  * @adap: the adapter to register (with adap->nr initialized)
1298  * Context: can sleep
1299  *
1300  * See i2c_add_numbered_adapter() for details.
1301  */
1302 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1303 {
1304         int id;
1305
1306         mutex_lock(&core_lock);
1307         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1308         mutex_unlock(&core_lock);
1309         if (WARN(id < 0, "couldn't get idr"))
1310                 return id == -ENOSPC ? -EBUSY : id;
1311
1312         return i2c_register_adapter(adap);
1313 }
1314
1315 /**
1316  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1317  * @adapter: the adapter to add
1318  * Context: can sleep
1319  *
1320  * This routine is used to declare an I2C adapter when its bus number
1321  * doesn't matter or when its bus number is specified by an dt alias.
1322  * Examples of bases when the bus number doesn't matter: I2C adapters
1323  * dynamically added by USB links or PCI plugin cards.
1324  *
1325  * When this returns zero, a new bus number was allocated and stored
1326  * in adap->nr, and the specified adapter became available for clients.
1327  * Otherwise, a negative errno value is returned.
1328  */
1329 int i2c_add_adapter(struct i2c_adapter *adapter)
1330 {
1331         struct device *dev = &adapter->dev;
1332         int id;
1333
1334         if (dev->of_node) {
1335                 id = of_alias_get_id(dev->of_node, "i2c");
1336                 if (id >= 0) {
1337                         adapter->nr = id;
1338                         return __i2c_add_numbered_adapter(adapter);
1339                 }
1340         }
1341
1342         mutex_lock(&core_lock);
1343         id = idr_alloc(&i2c_adapter_idr, adapter,
1344                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1345         mutex_unlock(&core_lock);
1346         if (WARN(id < 0, "couldn't get idr"))
1347                 return id;
1348
1349         adapter->nr = id;
1350
1351         return i2c_register_adapter(adapter);
1352 }
1353 EXPORT_SYMBOL(i2c_add_adapter);
1354
1355 /**
1356  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1357  * @adap: the adapter to register (with adap->nr initialized)
1358  * Context: can sleep
1359  *
1360  * This routine is used to declare an I2C adapter when its bus number
1361  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1362  * or otherwise built in to the system's mainboard, and where i2c_board_info
1363  * is used to properly configure I2C devices.
1364  *
1365  * If the requested bus number is set to -1, then this function will behave
1366  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1367  *
1368  * If no devices have pre-been declared for this bus, then be sure to
1369  * register the adapter before any dynamically allocated ones.  Otherwise
1370  * the required bus ID may not be available.
1371  *
1372  * When this returns zero, the specified adapter became available for
1373  * clients using the bus number provided in adap->nr.  Also, the table
1374  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1375  * and the appropriate driver model device nodes are created.  Otherwise, a
1376  * negative errno value is returned.
1377  */
1378 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1379 {
1380         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1381                 return i2c_add_adapter(adap);
1382
1383         return __i2c_add_numbered_adapter(adap);
1384 }
1385 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1386
1387 static void i2c_do_del_adapter(struct i2c_driver *driver,
1388                               struct i2c_adapter *adapter)
1389 {
1390         struct i2c_client *client, *_n;
1391
1392         /* Remove the devices we created ourselves as the result of hardware
1393          * probing (using a driver's detect method) */
1394         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1395                 if (client->adapter == adapter) {
1396                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1397                                 client->name, client->addr);
1398                         list_del(&client->detected);
1399                         i2c_unregister_device(client);
1400                 }
1401         }
1402 }
1403
1404 static int __unregister_client(struct device *dev, void *dummy)
1405 {
1406         struct i2c_client *client = i2c_verify_client(dev);
1407         if (client && strcmp(client->name, "dummy"))
1408                 i2c_unregister_device(client);
1409         return 0;
1410 }
1411
1412 static int __unregister_dummy(struct device *dev, void *dummy)
1413 {
1414         struct i2c_client *client = i2c_verify_client(dev);
1415         i2c_unregister_device(client);
1416         return 0;
1417 }
1418
1419 static int __process_removed_adapter(struct device_driver *d, void *data)
1420 {
1421         i2c_do_del_adapter(to_i2c_driver(d), data);
1422         return 0;
1423 }
1424
1425 /**
1426  * i2c_del_adapter - unregister I2C adapter
1427  * @adap: the adapter being unregistered
1428  * Context: can sleep
1429  *
1430  * This unregisters an I2C adapter which was previously registered
1431  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1432  */
1433 void i2c_del_adapter(struct i2c_adapter *adap)
1434 {
1435         struct i2c_adapter *found;
1436         struct i2c_client *client, *next;
1437
1438         /* First make sure that this adapter was ever added */
1439         mutex_lock(&core_lock);
1440         found = idr_find(&i2c_adapter_idr, adap->nr);
1441         mutex_unlock(&core_lock);
1442         if (found != adap) {
1443                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1444                 return;
1445         }
1446
1447         i2c_acpi_remove_space_handler(adap);
1448         /* Tell drivers about this removal */
1449         mutex_lock(&core_lock);
1450         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1451                                __process_removed_adapter);
1452         mutex_unlock(&core_lock);
1453
1454         /* Remove devices instantiated from sysfs */
1455         mutex_lock_nested(&adap->userspace_clients_lock,
1456                           i2c_adapter_depth(adap));
1457         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1458                                  detected) {
1459                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1460                         client->addr);
1461                 list_del(&client->detected);
1462                 i2c_unregister_device(client);
1463         }
1464         mutex_unlock(&adap->userspace_clients_lock);
1465
1466         /* Detach any active clients. This can't fail, thus we do not
1467          * check the returned value. This is a two-pass process, because
1468          * we can't remove the dummy devices during the first pass: they
1469          * could have been instantiated by real devices wishing to clean
1470          * them up properly, so we give them a chance to do that first. */
1471         device_for_each_child(&adap->dev, NULL, __unregister_client);
1472         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1473
1474 #ifdef CONFIG_I2C_COMPAT
1475         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1476                                  adap->dev.parent);
1477 #endif
1478
1479         /* device name is gone after device_unregister */
1480         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1481
1482         pm_runtime_disable(&adap->dev);
1483
1484         i2c_host_notify_irq_teardown(adap);
1485
1486         /* wait until all references to the device are gone
1487          *
1488          * FIXME: This is old code and should ideally be replaced by an
1489          * alternative which results in decoupling the lifetime of the struct
1490          * device from the i2c_adapter, like spi or netdev do. Any solution
1491          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1492          */
1493         init_completion(&adap->dev_released);
1494         device_unregister(&adap->dev);
1495         wait_for_completion(&adap->dev_released);
1496
1497         /* free bus id */
1498         mutex_lock(&core_lock);
1499         idr_remove(&i2c_adapter_idr, adap->nr);
1500         mutex_unlock(&core_lock);
1501
1502         /* Clear the device structure in case this adapter is ever going to be
1503            added again */
1504         memset(&adap->dev, 0, sizeof(adap->dev));
1505 }
1506 EXPORT_SYMBOL(i2c_del_adapter);
1507
1508 /**
1509  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1510  * @dev: The device to scan for I2C timing properties
1511  * @t: the i2c_timings struct to be filled with values
1512  * @use_defaults: bool to use sane defaults derived from the I2C specification
1513  *                when properties are not found, otherwise use 0
1514  *
1515  * Scan the device for the generic I2C properties describing timing parameters
1516  * for the signal and fill the given struct with the results. If a property was
1517  * not found and use_defaults was true, then maximum timings are assumed which
1518  * are derived from the I2C specification. If use_defaults is not used, the
1519  * results will be 0, so drivers can apply their own defaults later. The latter
1520  * is mainly intended for avoiding regressions of existing drivers which want
1521  * to switch to this function. New drivers almost always should use the defaults.
1522  */
1523
1524 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1525 {
1526         int ret;
1527
1528         memset(t, 0, sizeof(*t));
1529
1530         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1531         if (ret && use_defaults)
1532                 t->bus_freq_hz = 100000;
1533
1534         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1535         if (ret && use_defaults) {
1536                 if (t->bus_freq_hz <= 100000)
1537                         t->scl_rise_ns = 1000;
1538                 else if (t->bus_freq_hz <= 400000)
1539                         t->scl_rise_ns = 300;
1540                 else
1541                         t->scl_rise_ns = 120;
1542         }
1543
1544         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1545         if (ret && use_defaults) {
1546                 if (t->bus_freq_hz <= 400000)
1547                         t->scl_fall_ns = 300;
1548                 else
1549                         t->scl_fall_ns = 120;
1550         }
1551
1552         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1553
1554         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1555         if (ret && use_defaults)
1556                 t->sda_fall_ns = t->scl_fall_ns;
1557 }
1558 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1559
1560 /* ------------------------------------------------------------------------- */
1561
1562 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1563 {
1564         int res;
1565
1566         mutex_lock(&core_lock);
1567         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1568         mutex_unlock(&core_lock);
1569
1570         return res;
1571 }
1572 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1573
1574 static int __process_new_driver(struct device *dev, void *data)
1575 {
1576         if (dev->type != &i2c_adapter_type)
1577                 return 0;
1578         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1579 }
1580
1581 /*
1582  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1583  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1584  */
1585
1586 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1587 {
1588         int res;
1589
1590         /* Can't register until after driver model init */
1591         if (WARN_ON(!is_registered))
1592                 return -EAGAIN;
1593
1594         /* add the driver to the list of i2c drivers in the driver core */
1595         driver->driver.owner = owner;
1596         driver->driver.bus = &i2c_bus_type;
1597         INIT_LIST_HEAD(&driver->clients);
1598
1599         /* When registration returns, the driver core
1600          * will have called probe() for all matching-but-unbound devices.
1601          */
1602         res = driver_register(&driver->driver);
1603         if (res)
1604                 return res;
1605
1606         pr_debug("driver [%s] registered\n", driver->driver.name);
1607
1608         /* Walk the adapters that are already present */
1609         i2c_for_each_dev(driver, __process_new_driver);
1610
1611         return 0;
1612 }
1613 EXPORT_SYMBOL(i2c_register_driver);
1614
1615 static int __process_removed_driver(struct device *dev, void *data)
1616 {
1617         if (dev->type == &i2c_adapter_type)
1618                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1619         return 0;
1620 }
1621
1622 /**
1623  * i2c_del_driver - unregister I2C driver
1624  * @driver: the driver being unregistered
1625  * Context: can sleep
1626  */
1627 void i2c_del_driver(struct i2c_driver *driver)
1628 {
1629         i2c_for_each_dev(driver, __process_removed_driver);
1630
1631         driver_unregister(&driver->driver);
1632         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1633 }
1634 EXPORT_SYMBOL(i2c_del_driver);
1635
1636 /* ------------------------------------------------------------------------- */
1637
1638 /**
1639  * i2c_use_client - increments the reference count of the i2c client structure
1640  * @client: the client being referenced
1641  *
1642  * Each live reference to a client should be refcounted. The driver model does
1643  * that automatically as part of driver binding, so that most drivers don't
1644  * need to do this explicitly: they hold a reference until they're unbound
1645  * from the device.
1646  *
1647  * A pointer to the client with the incremented reference counter is returned.
1648  */
1649 struct i2c_client *i2c_use_client(struct i2c_client *client)
1650 {
1651         if (client && get_device(&client->dev))
1652                 return client;
1653         return NULL;
1654 }
1655 EXPORT_SYMBOL(i2c_use_client);
1656
1657 /**
1658  * i2c_release_client - release a use of the i2c client structure
1659  * @client: the client being no longer referenced
1660  *
1661  * Must be called when a user of a client is finished with it.
1662  */
1663 void i2c_release_client(struct i2c_client *client)
1664 {
1665         if (client)
1666                 put_device(&client->dev);
1667 }
1668 EXPORT_SYMBOL(i2c_release_client);
1669
1670 struct i2c_cmd_arg {
1671         unsigned        cmd;
1672         void            *arg;
1673 };
1674
1675 static int i2c_cmd(struct device *dev, void *_arg)
1676 {
1677         struct i2c_client       *client = i2c_verify_client(dev);
1678         struct i2c_cmd_arg      *arg = _arg;
1679         struct i2c_driver       *driver;
1680
1681         if (!client || !client->dev.driver)
1682                 return 0;
1683
1684         driver = to_i2c_driver(client->dev.driver);
1685         if (driver->command)
1686                 driver->command(client, arg->cmd, arg->arg);
1687         return 0;
1688 }
1689
1690 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1691 {
1692         struct i2c_cmd_arg      cmd_arg;
1693
1694         cmd_arg.cmd = cmd;
1695         cmd_arg.arg = arg;
1696         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1697 }
1698 EXPORT_SYMBOL(i2c_clients_command);
1699
1700 static int __init i2c_init(void)
1701 {
1702         int retval;
1703
1704         retval = of_alias_get_highest_id("i2c");
1705
1706         down_write(&__i2c_board_lock);
1707         if (retval >= __i2c_first_dynamic_bus_num)
1708                 __i2c_first_dynamic_bus_num = retval + 1;
1709         up_write(&__i2c_board_lock);
1710
1711         retval = bus_register(&i2c_bus_type);
1712         if (retval)
1713                 return retval;
1714
1715         is_registered = true;
1716
1717 #ifdef CONFIG_I2C_COMPAT
1718         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1719         if (!i2c_adapter_compat_class) {
1720                 retval = -ENOMEM;
1721                 goto bus_err;
1722         }
1723 #endif
1724         retval = i2c_add_driver(&dummy_driver);
1725         if (retval)
1726                 goto class_err;
1727
1728         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1729                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1730         if (IS_ENABLED(CONFIG_ACPI))
1731                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1732
1733         return 0;
1734
1735 class_err:
1736 #ifdef CONFIG_I2C_COMPAT
1737         class_compat_unregister(i2c_adapter_compat_class);
1738 bus_err:
1739 #endif
1740         is_registered = false;
1741         bus_unregister(&i2c_bus_type);
1742         return retval;
1743 }
1744
1745 static void __exit i2c_exit(void)
1746 {
1747         if (IS_ENABLED(CONFIG_ACPI))
1748                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1749         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1750                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1751         i2c_del_driver(&dummy_driver);
1752 #ifdef CONFIG_I2C_COMPAT
1753         class_compat_unregister(i2c_adapter_compat_class);
1754 #endif
1755         bus_unregister(&i2c_bus_type);
1756         tracepoint_synchronize_unregister();
1757 }
1758
1759 /* We must initialize early, because some subsystems register i2c drivers
1760  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1761  */
1762 postcore_initcall(i2c_init);
1763 module_exit(i2c_exit);
1764
1765 /* ----------------------------------------------------
1766  * the functional interface to the i2c busses.
1767  * ----------------------------------------------------
1768  */
1769
1770 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1771 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1772
1773 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1774 {
1775         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1776                             err_msg, msg->addr, msg->len,
1777                             msg->flags & I2C_M_RD ? "read" : "write");
1778         return -EOPNOTSUPP;
1779 }
1780
1781 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1782 {
1783         const struct i2c_adapter_quirks *q = adap->quirks;
1784         int max_num = q->max_num_msgs, i;
1785         bool do_len_check = true;
1786
1787         if (q->flags & I2C_AQ_COMB) {
1788                 max_num = 2;
1789
1790                 /* special checks for combined messages */
1791                 if (num == 2) {
1792                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1793                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1794
1795                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1796                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1797
1798                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1799                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1800
1801                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1802                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1803
1804                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1805                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1806
1807                         do_len_check = false;
1808                 }
1809         }
1810
1811         if (i2c_quirk_exceeded(num, max_num))
1812                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1813
1814         for (i = 0; i < num; i++) {
1815                 u16 len = msgs[i].len;
1816
1817                 if (msgs[i].flags & I2C_M_RD) {
1818                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1819                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1820                 } else {
1821                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1822                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1823                 }
1824         }
1825
1826         return 0;
1827 }
1828
1829 /**
1830  * __i2c_transfer - unlocked flavor of i2c_transfer
1831  * @adap: Handle to I2C bus
1832  * @msgs: One or more messages to execute before STOP is issued to
1833  *      terminate the operation; each message begins with a START.
1834  * @num: Number of messages to be executed.
1835  *
1836  * Returns negative errno, else the number of messages executed.
1837  *
1838  * Adapter lock must be held when calling this function. No debug logging
1839  * takes place. adap->algo->master_xfer existence isn't checked.
1840  */
1841 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1842 {
1843         unsigned long orig_jiffies;
1844         int ret, try;
1845
1846         if (WARN_ON(!msgs || num < 1))
1847                 return -EINVAL;
1848
1849         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1850                 return -EOPNOTSUPP;
1851
1852         /*
1853          * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
1854          * enabled.  This is an efficient way of keeping the for-loop from
1855          * being executed when not needed.
1856          */
1857         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1858                 int i;
1859                 for (i = 0; i < num; i++)
1860                         if (msgs[i].flags & I2C_M_RD)
1861                                 trace_i2c_read(adap, &msgs[i], i);
1862                         else
1863                                 trace_i2c_write(adap, &msgs[i], i);
1864         }
1865
1866         /* Retry automatically on arbitration loss */
1867         orig_jiffies = jiffies;
1868         for (ret = 0, try = 0; try <= adap->retries; try++) {
1869                 ret = adap->algo->master_xfer(adap, msgs, num);
1870                 if (ret != -EAGAIN)
1871                         break;
1872                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1873                         break;
1874         }
1875
1876         if (static_branch_unlikely(&i2c_trace_msg_key)) {
1877                 int i;
1878                 for (i = 0; i < ret; i++)
1879                         if (msgs[i].flags & I2C_M_RD)
1880                                 trace_i2c_reply(adap, &msgs[i], i);
1881                 trace_i2c_result(adap, num, ret);
1882         }
1883
1884         return ret;
1885 }
1886 EXPORT_SYMBOL(__i2c_transfer);
1887
1888 /**
1889  * i2c_transfer - execute a single or combined I2C message
1890  * @adap: Handle to I2C bus
1891  * @msgs: One or more messages to execute before STOP is issued to
1892  *      terminate the operation; each message begins with a START.
1893  * @num: Number of messages to be executed.
1894  *
1895  * Returns negative errno, else the number of messages executed.
1896  *
1897  * Note that there is no requirement that each message be sent to
1898  * the same slave address, although that is the most common model.
1899  */
1900 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1901 {
1902         int ret;
1903
1904         /* REVISIT the fault reporting model here is weak:
1905          *
1906          *  - When we get an error after receiving N bytes from a slave,
1907          *    there is no way to report "N".
1908          *
1909          *  - When we get a NAK after transmitting N bytes to a slave,
1910          *    there is no way to report "N" ... or to let the master
1911          *    continue executing the rest of this combined message, if
1912          *    that's the appropriate response.
1913          *
1914          *  - When for example "num" is two and we successfully complete
1915          *    the first message but get an error part way through the
1916          *    second, it's unclear whether that should be reported as
1917          *    one (discarding status on the second message) or errno
1918          *    (discarding status on the first one).
1919          */
1920
1921         if (adap->algo->master_xfer) {
1922 #ifdef DEBUG
1923                 for (ret = 0; ret < num; ret++) {
1924                         dev_dbg(&adap->dev,
1925                                 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1926                                 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1927                                 msgs[ret].addr, msgs[ret].len,
1928                                 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1929                 }
1930 #endif
1931
1932                 if (in_atomic() || irqs_disabled()) {
1933                         ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1934                         if (!ret)
1935                                 /* I2C activity is ongoing. */
1936                                 return -EAGAIN;
1937                 } else {
1938                         i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1939                 }
1940
1941                 ret = __i2c_transfer(adap, msgs, num);
1942                 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1943
1944                 return ret;
1945         } else {
1946                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1947                 return -EOPNOTSUPP;
1948         }
1949 }
1950 EXPORT_SYMBOL(i2c_transfer);
1951
1952 /**
1953  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1954  *                             to/from a buffer
1955  * @client: Handle to slave device
1956  * @buf: Where the data is stored
1957  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1958  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1959  *
1960  * Returns negative errno, or else the number of bytes transferred.
1961  */
1962 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1963                               int count, u16 flags)
1964 {
1965         int ret;
1966         struct i2c_msg msg = {
1967                 .addr = client->addr,
1968                 .flags = flags | (client->flags & I2C_M_TEN),
1969                 .len = count,
1970                 .buf = buf,
1971         };
1972
1973         ret = i2c_transfer(client->adapter, &msg, 1);
1974
1975         /*
1976          * If everything went ok (i.e. 1 msg transferred), return #bytes
1977          * transferred, else error code.
1978          */
1979         return (ret == 1) ? count : ret;
1980 }
1981 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1982
1983 /**
1984  * i2c_get_device_id - get manufacturer, part id and die revision of a device
1985  * @client: The device to query
1986  * @id: The queried information
1987  *
1988  * Returns negative errno on error, zero on success.
1989  */
1990 int i2c_get_device_id(const struct i2c_client *client,
1991                       struct i2c_device_identity *id)
1992 {
1993         struct i2c_adapter *adap = client->adapter;
1994         union i2c_smbus_data raw_id;
1995         int ret;
1996
1997         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
1998                 return -EOPNOTSUPP;
1999
2000         raw_id.block[0] = 3;
2001         ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2002                              I2C_SMBUS_READ, client->addr << 1,
2003                              I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2004         if (ret)
2005                 return ret;
2006
2007         id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2008         id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2009         id->die_revision = raw_id.block[3] & 0x7;
2010         return 0;
2011 }
2012 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2013
2014 /* ----------------------------------------------------
2015  * the i2c address scanning function
2016  * Will not work for 10-bit addresses!
2017  * ----------------------------------------------------
2018  */
2019
2020 /*
2021  * Legacy default probe function, mostly relevant for SMBus. The default
2022  * probe method is a quick write, but it is known to corrupt the 24RF08
2023  * EEPROMs due to a state machine bug, and could also irreversibly
2024  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2025  * we use a short byte read instead. Also, some bus drivers don't implement
2026  * quick write, so we fallback to a byte read in that case too.
2027  * On x86, there is another special case for FSC hardware monitoring chips,
2028  * which want regular byte reads (address 0x73.) Fortunately, these are the
2029  * only known chips using this I2C address on PC hardware.
2030  * Returns 1 if probe succeeded, 0 if not.
2031  */
2032 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2033 {
2034         int err;
2035         union i2c_smbus_data dummy;
2036
2037 #ifdef CONFIG_X86
2038         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2039          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2040                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2041                                      I2C_SMBUS_BYTE_DATA, &dummy);
2042         else
2043 #endif
2044         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2045          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2046                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2047                                      I2C_SMBUS_QUICK, NULL);
2048         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2049                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2050                                      I2C_SMBUS_BYTE, &dummy);
2051         else {
2052                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2053                          addr);
2054                 err = -EOPNOTSUPP;
2055         }
2056
2057         return err >= 0;
2058 }
2059
2060 static int i2c_detect_address(struct i2c_client *temp_client,
2061                               struct i2c_driver *driver)
2062 {
2063         struct i2c_board_info info;
2064         struct i2c_adapter *adapter = temp_client->adapter;
2065         int addr = temp_client->addr;
2066         int err;
2067
2068         /* Make sure the address is valid */
2069         err = i2c_check_7bit_addr_validity_strict(addr);
2070         if (err) {
2071                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2072                          addr);
2073                 return err;
2074         }
2075
2076         /* Skip if already in use (7 bit, no need to encode flags) */
2077         if (i2c_check_addr_busy(adapter, addr))
2078                 return 0;
2079
2080         /* Make sure there is something at this address */
2081         if (!i2c_default_probe(adapter, addr))
2082                 return 0;
2083
2084         /* Finally call the custom detection function */
2085         memset(&info, 0, sizeof(struct i2c_board_info));
2086         info.addr = addr;
2087         err = driver->detect(temp_client, &info);
2088         if (err) {
2089                 /* -ENODEV is returned if the detection fails. We catch it
2090                    here as this isn't an error. */
2091                 return err == -ENODEV ? 0 : err;
2092         }
2093
2094         /* Consistency check */
2095         if (info.type[0] == '\0') {
2096                 dev_err(&adapter->dev,
2097                         "%s detection function provided no name for 0x%x\n",
2098                         driver->driver.name, addr);
2099         } else {
2100                 struct i2c_client *client;
2101
2102                 /* Detection succeeded, instantiate the device */
2103                 if (adapter->class & I2C_CLASS_DEPRECATED)
2104                         dev_warn(&adapter->dev,
2105                                 "This adapter will soon drop class based instantiation of devices. "
2106                                 "Please make sure client 0x%02x gets instantiated by other means. "
2107                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2108                                 info.addr);
2109
2110                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2111                         info.type, info.addr);
2112                 client = i2c_new_device(adapter, &info);
2113                 if (client)
2114                         list_add_tail(&client->detected, &driver->clients);
2115                 else
2116                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2117                                 info.type, info.addr);
2118         }
2119         return 0;
2120 }
2121
2122 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2123 {
2124         const unsigned short *address_list;
2125         struct i2c_client *temp_client;
2126         int i, err = 0;
2127         int adap_id = i2c_adapter_id(adapter);
2128
2129         address_list = driver->address_list;
2130         if (!driver->detect || !address_list)
2131                 return 0;
2132
2133         /* Warn that the adapter lost class based instantiation */
2134         if (adapter->class == I2C_CLASS_DEPRECATED) {
2135                 dev_dbg(&adapter->dev,
2136                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2137                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2138                         driver->driver.name);
2139                 return 0;
2140         }
2141
2142         /* Stop here if the classes do not match */
2143         if (!(adapter->class & driver->class))
2144                 return 0;
2145
2146         /* Set up a temporary client to help detect callback */
2147         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2148         if (!temp_client)
2149                 return -ENOMEM;
2150         temp_client->adapter = adapter;
2151
2152         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2153                 dev_dbg(&adapter->dev,
2154                         "found normal entry for adapter %d, addr 0x%02x\n",
2155                         adap_id, address_list[i]);
2156                 temp_client->addr = address_list[i];
2157                 err = i2c_detect_address(temp_client, driver);
2158                 if (unlikely(err))
2159                         break;
2160         }
2161
2162         kfree(temp_client);
2163         return err;
2164 }
2165
2166 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2167 {
2168         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2169                               I2C_SMBUS_QUICK, NULL) >= 0;
2170 }
2171 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2172
2173 struct i2c_client *
2174 i2c_new_probed_device(struct i2c_adapter *adap,
2175                       struct i2c_board_info *info,
2176                       unsigned short const *addr_list,
2177                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2178 {
2179         int i;
2180
2181         if (!probe)
2182                 probe = i2c_default_probe;
2183
2184         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2185                 /* Check address validity */
2186                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2187                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2188                                  addr_list[i]);
2189                         continue;
2190                 }
2191
2192                 /* Check address availability (7 bit, no need to encode flags) */
2193                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2194                         dev_dbg(&adap->dev,
2195                                 "Address 0x%02x already in use, not probing\n",
2196                                 addr_list[i]);
2197                         continue;
2198                 }
2199
2200                 /* Test address responsiveness */
2201                 if (probe(adap, addr_list[i]))
2202                         break;
2203         }
2204
2205         if (addr_list[i] == I2C_CLIENT_END) {
2206                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2207                 return NULL;
2208         }
2209
2210         info->addr = addr_list[i];
2211         return i2c_new_device(adap, info);
2212 }
2213 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2214
2215 struct i2c_adapter *i2c_get_adapter(int nr)
2216 {
2217         struct i2c_adapter *adapter;
2218
2219         mutex_lock(&core_lock);
2220         adapter = idr_find(&i2c_adapter_idr, nr);
2221         if (!adapter)
2222                 goto exit;
2223
2224         if (try_module_get(adapter->owner))
2225                 get_device(&adapter->dev);
2226         else
2227                 adapter = NULL;
2228
2229  exit:
2230         mutex_unlock(&core_lock);
2231         return adapter;
2232 }
2233 EXPORT_SYMBOL(i2c_get_adapter);
2234
2235 void i2c_put_adapter(struct i2c_adapter *adap)
2236 {
2237         if (!adap)
2238                 return;
2239
2240         put_device(&adap->dev);
2241         module_put(adap->owner);
2242 }
2243 EXPORT_SYMBOL(i2c_put_adapter);
2244
2245 /**
2246  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2247  * @msg: the message to be checked
2248  * @threshold: the minimum number of bytes for which using DMA makes sense
2249  *
2250  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2251  *         Or a valid pointer to be used with DMA. After use, release it by
2252  *         calling i2c_release_dma_safe_msg_buf().
2253  *
2254  * This function must only be called from process context!
2255  */
2256 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2257 {
2258         if (msg->len < threshold)
2259                 return NULL;
2260
2261         if (msg->flags & I2C_M_DMA_SAFE)
2262                 return msg->buf;
2263
2264         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2265                  msg->addr, msg->len);
2266
2267         if (msg->flags & I2C_M_RD)
2268                 return kzalloc(msg->len, GFP_KERNEL);
2269         else
2270                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2271 }
2272 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2273
2274 /**
2275  * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2276  * @msg: the message to be synced with
2277  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2278  */
2279 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2280 {
2281         if (!buf || buf == msg->buf)
2282                 return;
2283
2284         if (msg->flags & I2C_M_RD)
2285                 memcpy(msg->buf, buf, msg->len);
2286
2287         kfree(buf);
2288 }
2289 EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2290
2291 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2292 MODULE_DESCRIPTION("I2C-Bus main module");
2293 MODULE_LICENSE("GPL");