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 /*
  62  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  63  * deletion of detected devices, and attach_adapter calls are serialized
  64  */
  65 static DEFINE_MUTEX(core_lock);
  66 static DEFINE_IDR(i2c_adapter_idr);
  67
  68 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  69
  70 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
  71 static bool is_registered;
  72
  73 int i2c_transfer_trace_reg(void)
  74 {
  75         static_key_slow_inc(&i2c_trace_msg);
  76         return 0;
  77 }
  78
  79 void i2c_transfer_trace_unreg(void)
  80 {
  81         static_key_slow_dec(&i2c_trace_msg);
  82 }
  83
  84 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  85                                                 const struct i2c_client *client)
  86 {
  87         if (!(id && client))
  88                 return NULL;
  89
  90         while (id->name[0]) {
  91                 if (strcmp(client->name, id->name) == 0)
  92                         return id;
  93                 id++;
  94         }
  95         return NULL;
  96 }
  97 EXPORT_SYMBOL_GPL(i2c_match_id);
  98
  99 static int i2c_device_match(struct device *dev, struct device_driver *drv)
 100 {
 101         struct i2c_client       *client = i2c_verify_client(dev);
 102         struct i2c_driver       *driver;
 103
 104
 105         /* Attempt an OF style match */
 106         if (i2c_of_match_device(drv->of_match_table, client))
 107                 return 1;
 108
 109         /* Then ACPI style match */
 110         if (acpi_driver_match_device(dev, drv))
 111                 return 1;
 112
 113         driver = to_i2c_driver(drv);
 114
 115         /* Finally an I2C match */
 116         if (i2c_match_id(driver->id_table, client))
 117                 return 1;
 118
 119         return 0;
 120 }
 121
 122 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 123 {
 124         struct i2c_client *client = to_i2c_client(dev);
 125         int rc;
 126
 127         rc = acpi_device_uevent_modalias(dev, env);
 128         if (rc != -ENODEV)
 129                 return rc;
 130
 131         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 132 }
 133
 134 /* i2c bus recovery routines */
 135 static int get_scl_gpio_value(struct i2c_adapter *adap)
 136 {
 137         return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 138 }
 139
 140 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 141 {
 142         gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 143 }
 144
 145 static int get_sda_gpio_value(struct i2c_adapter *adap)
 146 {
 147         return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 148 }
 149
 150 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 151 {
 152         gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 153 }
 154
 155 /*
 156  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 157  * We will generate clock with rate 100 KHz and so duration of both clock levels
 158  * is: delay in ns = (10^6 / 100) / 2
 159  */
 160 #define RECOVERY_NDELAY         5000
 161 #define RECOVERY_CLK_CNT        9
 162
 163 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 164 {
 165         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 166         int i = 0, val = 1, ret = 0;
 167
 168         if (bri->prepare_recovery)
 169                 bri->prepare_recovery(adap);
 170
 171         bri->set_scl(adap, val);
 172         if (bri->set_sda)
 173                 bri->set_sda(adap, 1);
 174         ndelay(RECOVERY_NDELAY);
 175
 176         /*
 177          * By this time SCL is high, as we need to give 9 falling-rising edges
 178          */
 179         while (i++ < RECOVERY_CLK_CNT * 2) {
 180                 if (val) {
 181                         /* SCL shouldn't be low here */
 182                         if (!bri->get_scl(adap)) {
 183                                 dev_err(&adap->dev,
 184                                         "SCL is stuck low, exit recovery\n");
 185                                 ret = -EBUSY;
 186                                 break;
 187                         }
 188                         /* Break if SDA is high */
 189                         if (bri->get_sda && bri->get_sda(adap))
 190                                 break;
 191                 }
 192
 193                 val = !val;
 194                 bri->set_scl(adap, val);
 195                 ndelay(RECOVERY_NDELAY);
 196         }
 197
 198         /* check if recovery actually succeeded */
 199         if (bri->get_sda && !bri->get_sda(adap))
 200                 ret = -EBUSY;
 201
 202         /* If all went well, send STOP for a sane bus state. */
 203         if (ret == 0 && bri->set_sda) {
 204                 bri->set_scl(adap, 0);
 205                 ndelay(RECOVERY_NDELAY / 2);
 206                 bri->set_sda(adap, 0);
 207                 ndelay(RECOVERY_NDELAY / 2);
 208                 bri->set_scl(adap, 1);
 209                 ndelay(RECOVERY_NDELAY / 2);
 210                 bri->set_sda(adap, 1);
 211                 ndelay(RECOVERY_NDELAY / 2);
 212         }
 213
 214         if (bri->unprepare_recovery)
 215                 bri->unprepare_recovery(adap);
 216
 217         return ret;
 218 }
 219 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 220
 221 int i2c_recover_bus(struct i2c_adapter *adap)
 222 {
 223         if (!adap->bus_recovery_info)
 224                 return -EOPNOTSUPP;
 225
 226         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 227         return adap->bus_recovery_info->recover_bus(adap);
 228 }
 229 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 230
 231 static void i2c_init_recovery(struct i2c_adapter *adap)
 232 {
 233         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 234         char *err_str;
 235
 236         if (!bri)
 237                 return;
 238
 239         if (!bri->recover_bus) {
 240                 err_str = "no recover_bus() found";
 241                 goto err;
 242         }
 243
 244         if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 245                 bri->get_scl = get_scl_gpio_value;
 246                 bri->set_scl = set_scl_gpio_value;
 247                 if (bri->sda_gpiod) {
 248                         bri->get_sda = get_sda_gpio_value;
 249                         /* FIXME: add proper flag instead of '0' once available */
 250                         if (gpiod_get_direction(bri->sda_gpiod) == 0)
 251                                 bri->set_sda = set_sda_gpio_value;
 252                 }
 253                 return;
 254         }
 255
 256         if (bri->recover_bus == i2c_generic_scl_recovery) {
 257                 /* Generic SCL recovery */
 258                 if (!bri->set_scl || !bri->get_scl) {
 259                         err_str = "no {get|set}_scl() found";
 260                         goto err;
 261                 }
 262         }
 263
 264         return;
 265  err:
 266         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 267         adap->bus_recovery_info = NULL;
 268 }
 269
 270 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 271 {
 272         struct i2c_adapter *adap = client->adapter;
 273         unsigned int irq;
 274
 275         if (!adap->host_notify_domain)
 276                 return -ENXIO;
 277
 278         if (client->flags & I2C_CLIENT_TEN)
 279                 return -EINVAL;
 280
 281         irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 282         if (!irq)
 283                 irq = irq_create_mapping(adap->host_notify_domain,
 284                                          client->addr);
 285
 286         return irq > 0 ? irq : -ENXIO;
 287 }
 288
 289 static int i2c_device_probe(struct device *dev)
 290 {
 291         struct i2c_client       *client = i2c_verify_client(dev);
 292         struct i2c_driver       *driver;
 293         int status;
 294
 295         if (!client)
 296                 return 0;
 297
 298         driver = to_i2c_driver(dev->driver);
 299
 300         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 301                 int irq = -ENOENT;
 302
 303                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 304                         dev_dbg(dev, "Using Host Notify IRQ\n");
 305                         irq = i2c_smbus_host_notify_to_irq(client);
 306                 } else if (dev->of_node) {
 307                         irq = of_irq_get_byname(dev->of_node, "irq");
 308                         if (irq == -EINVAL || irq == -ENODATA)
 309                                 irq = of_irq_get(dev->of_node, 0);
 310                 } else if (ACPI_COMPANION(dev)) {
 311                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 312                 }
 313                 if (irq == -EPROBE_DEFER)
 314                         return irq;
 315
 316                 if (irq < 0)
 317                         irq = 0;
 318
 319                 client->irq = irq;
 320         }
 321
 322         /*
 323          * An I2C ID table is not mandatory, if and only if, a suitable OF
 324          * or ACPI ID table is supplied for the probing device.
 325          */
 326         if (!driver->id_table &&
 327             !i2c_acpi_match_device(dev->driver->acpi_match_table, client) &&
 328             !i2c_of_match_device(dev->driver->of_match_table, client))
 329                 return -ENODEV;
 330
 331         if (client->flags & I2C_CLIENT_WAKE) {
 332                 int wakeirq = -ENOENT;
 333
 334                 if (dev->of_node) {
 335                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 336                         if (wakeirq == -EPROBE_DEFER)
 337                                 return wakeirq;
 338                 }
 339
 340                 device_init_wakeup(&client->dev, true);
 341
 342                 if (wakeirq > 0 && wakeirq != client->irq)
 343                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 344                 else if (client->irq > 0)
 345                         status = dev_pm_set_wake_irq(dev, client->irq);
 346                 else
 347                         status = 0;
 348
 349                 if (status)
 350                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 351         }
 352
 353         dev_dbg(dev, "probe\n");
 354
 355         status = of_clk_set_defaults(dev->of_node, false);
 356         if (status < 0)
 357                 goto err_clear_wakeup_irq;
 358
 359         status = dev_pm_domain_attach(&client->dev, true);
 360         if (status == -EPROBE_DEFER)
 361                 goto err_clear_wakeup_irq;
 362
 363         /*
 364          * When there are no more users of probe(),
 365          * rename probe_new to probe.
 366          */
 367         if (driver->probe_new)
 368                 status = driver->probe_new(client);
 369         else if (driver->probe)
 370                 status = driver->probe(client,
 371                                        i2c_match_id(driver->id_table, client));
 372         else
 373                 status = -EINVAL;
 374
 375         if (status)
 376                 goto err_detach_pm_domain;
 377
 378         return 0;
 379
 380 err_detach_pm_domain:
 381         dev_pm_domain_detach(&client->dev, true);
 382 err_clear_wakeup_irq:
 383         dev_pm_clear_wake_irq(&client->dev);
 384         device_init_wakeup(&client->dev, false);
 385         return status;
 386 }
 387
 388 static int i2c_device_remove(struct device *dev)
 389 {
 390         struct i2c_client       *client = i2c_verify_client(dev);
 391         struct i2c_driver       *driver;
 392         int status = 0;
 393
 394         if (!client || !dev->driver)
 395                 return 0;
 396
 397         driver = to_i2c_driver(dev->driver);
 398         if (driver->remove) {
 399                 dev_dbg(dev, "remove\n");
 400                 status = driver->remove(client);
 401         }
 402
 403         dev_pm_domain_detach(&client->dev, true);
 404
 405         dev_pm_clear_wake_irq(&client->dev);
 406         device_init_wakeup(&client->dev, false);
 407
 408         return status;
 409 }
 410
 411 static void i2c_device_shutdown(struct device *dev)
 412 {
 413         struct i2c_client *client = i2c_verify_client(dev);
 414         struct i2c_driver *driver;
 415
 416         if (!client || !dev->driver)
 417                 return;
 418         driver = to_i2c_driver(dev->driver);
 419         if (driver->shutdown)
 420                 driver->shutdown(client);
 421 }
 422
 423 static void i2c_client_dev_release(struct device *dev)
 424 {
 425         kfree(to_i2c_client(dev));
 426 }
 427
 428 static ssize_t
 429 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 430 {
 431         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 432                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 433 }
 434 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 435
 436 static ssize_t
 437 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 438 {
 439         struct i2c_client *client = to_i2c_client(dev);
 440         int len;
 441
 442         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 443         if (len != -ENODEV)
 444                 return len;
 445
 446         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 447 }
 448 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 449
 450 static struct attribute *i2c_dev_attrs[] = {
 451         &dev_attr_name.attr,
 452         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 453         &dev_attr_modalias.attr,
 454         NULL
 455 };
 456 ATTRIBUTE_GROUPS(i2c_dev);
 457
 458 struct bus_type i2c_bus_type = {
 459         .name           = "i2c",
 460         .match          = i2c_device_match,
 461         .probe          = i2c_device_probe,
 462         .remove         = i2c_device_remove,
 463         .shutdown       = i2c_device_shutdown,
 464 };
 465 EXPORT_SYMBOL_GPL(i2c_bus_type);
 466
 467 struct device_type i2c_client_type = {
 468         .groups         = i2c_dev_groups,
 469         .uevent         = i2c_device_uevent,
 470         .release        = i2c_client_dev_release,
 471 };
 472 EXPORT_SYMBOL_GPL(i2c_client_type);
 473
 474
 475 /**
 476  * i2c_verify_client - return parameter as i2c_client, or NULL
 477  * @dev: device, probably from some driver model iterator
 478  *
 479  * When traversing the driver model tree, perhaps using driver model
 480  * iterators like @device_for_each_child(), you can't assume very much
 481  * about the nodes you find.  Use this function to avoid oopses caused
 482  * by wrongly treating some non-I2C device as an i2c_client.
 483  */
 484 struct i2c_client *i2c_verify_client(struct device *dev)
 485 {
 486         return (dev->type == &i2c_client_type)
 487                         ? to_i2c_client(dev)
 488                         : NULL;
 489 }
 490 EXPORT_SYMBOL(i2c_verify_client);
 491
 492
 493 /* Return a unique address which takes the flags of the client into account */
 494 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 495 {
 496         unsigned short addr = client->addr;
 497
 498         /* For some client flags, add an arbitrary offset to avoid collisions */
 499         if (client->flags & I2C_CLIENT_TEN)
 500                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 501
 502         if (client->flags & I2C_CLIENT_SLAVE)
 503                 addr |= I2C_ADDR_OFFSET_SLAVE;
 504
 505         return addr;
 506 }
 507
 508 /* This is a permissive address validity check, I2C address map constraints
 509  * are purposely not enforced, except for the general call address. */
 510 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
 511 {
 512         if (flags & I2C_CLIENT_TEN) {
 513                 /* 10-bit address, all values are valid */
 514                 if (addr > 0x3ff)
 515                         return -EINVAL;
 516         } else {
 517                 /* 7-bit address, reject the general call address */
 518                 if (addr == 0x00 || addr > 0x7f)
 519                         return -EINVAL;
 520         }
 521         return 0;
 522 }
 523
 524 /* And this is a strict address validity check, used when probing. If a
 525  * device uses a reserved address, then it shouldn't be probed. 7-bit
 526  * addressing is assumed, 10-bit address devices are rare and should be
 527  * explicitly enumerated. */
 528 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 529 {
 530         /*
 531          * Reserved addresses per I2C specification:
 532          *  0x00       General call address / START byte
 533          *  0x01       CBUS address
 534          *  0x02       Reserved for different bus format
 535          *  0x03       Reserved for future purposes
 536          *  0x04-0x07  Hs-mode master code
 537          *  0x78-0x7b  10-bit slave addressing
 538          *  0x7c-0x7f  Reserved for future purposes
 539          */
 540         if (addr < 0x08 || addr > 0x77)
 541                 return -EINVAL;
 542         return 0;
 543 }
 544
 545 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 546 {
 547         struct i2c_client       *client = i2c_verify_client(dev);
 548         int                     addr = *(int *)addrp;
 549
 550         if (client && i2c_encode_flags_to_addr(client) == addr)
 551                 return -EBUSY;
 552         return 0;
 553 }
 554
 555 /* walk up mux tree */
 556 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 557 {
 558         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 559         int result;
 560
 561         result = device_for_each_child(&adapter->dev, &addr,
 562                                         __i2c_check_addr_busy);
 563
 564         if (!result && parent)
 565                 result = i2c_check_mux_parents(parent, addr);
 566
 567         return result;
 568 }
 569
 570 /* recurse down mux tree */
 571 static int i2c_check_mux_children(struct device *dev, void *addrp)
 572 {
 573         int result;
 574
 575         if (dev->type == &i2c_adapter_type)
 576                 result = device_for_each_child(dev, addrp,
 577                                                 i2c_check_mux_children);
 578         else
 579                 result = __i2c_check_addr_busy(dev, addrp);
 580
 581         return result;
 582 }
 583
 584 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 585 {
 586         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 587         int result = 0;
 588
 589         if (parent)
 590                 result = i2c_check_mux_parents(parent, addr);
 591
 592         if (!result)
 593                 result = device_for_each_child(&adapter->dev, &addr,
 594                                                 i2c_check_mux_children);
 595
 596         return result;
 597 }
 598
 599 /**
 600  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 601  * @adapter: Target I2C bus segment
 602  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 603  *      locks only this branch in the adapter tree
 604  */
 605 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 606                                  unsigned int flags)
 607 {
 608         rt_mutex_lock(&adapter->bus_lock);
 609 }
 610
 611 /**
 612  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 613  * @adapter: Target I2C bus segment
 614  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 615  *      trylocks only this branch in the adapter tree
 616  */
 617 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 618                                    unsigned int flags)
 619 {
 620         return rt_mutex_trylock(&adapter->bus_lock);
 621 }
 622
 623 /**
 624  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 625  * @adapter: Target I2C bus segment
 626  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 627  *      unlocks only this branch in the adapter tree
 628  */
 629 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 630                                    unsigned int flags)
 631 {
 632         rt_mutex_unlock(&adapter->bus_lock);
 633 }
 634
 635 static void i2c_dev_set_name(struct i2c_adapter *adap,
 636                              struct i2c_client *client,
 637                              struct i2c_board_info const *info)
 638 {
 639         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 640
 641         if (info && info->dev_name) {
 642                 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 643                 return;
 644         }
 645
 646         if (adev) {
 647                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 648                 return;
 649         }
 650
 651         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 652                      i2c_encode_flags_to_addr(client));
 653 }
 654
 655 static int i2c_dev_irq_from_resources(const struct resource *resources,
 656                                       unsigned int num_resources)
 657 {
 658         struct irq_data *irqd;
 659         int i;
 660
 661         for (i = 0; i < num_resources; i++) {
 662                 const struct resource *r = &resources[i];
 663
 664                 if (resource_type(r) != IORESOURCE_IRQ)
 665                         continue;
 666
 667                 if (r->flags & IORESOURCE_BITS) {
 668                         irqd = irq_get_irq_data(r->start);
 669                         if (!irqd)
 670                                 break;
 671
 672                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 673                 }
 674
 675                 return r->start;
 676         }
 677
 678         return 0;
 679 }
 680
 681 /**
 682  * i2c_new_device - instantiate an i2c device
 683  * @adap: the adapter managing the device
 684  * @info: describes one I2C device; bus_num is ignored
 685  * Context: can sleep
 686  *
 687  * Create an i2c device. Binding is handled through driver model
 688  * probe()/remove() methods.  A driver may be bound to this device when we
 689  * return from this function, or any later moment (e.g. maybe hotplugging will
 690  * load the driver module).  This call is not appropriate for use by mainboard
 691  * initialization logic, which usually runs during an arch_initcall() long
 692  * before any i2c_adapter could exist.
 693  *
 694  * This returns the new i2c client, which may be saved for later use with
 695  * i2c_unregister_device(); or NULL to indicate an error.
 696  */
 697 struct i2c_client *
 698 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 699 {
 700         struct i2c_client       *client;
 701         int                     status;
 702
 703         client = kzalloc(sizeof *client, GFP_KERNEL);
 704         if (!client)
 705                 return NULL;
 706
 707         client->adapter = adap;
 708
 709         client->dev.platform_data = info->platform_data;
 710
 711         if (info->archdata)
 712                 client->dev.archdata = *info->archdata;
 713
 714         client->flags = info->flags;
 715         client->addr = info->addr;
 716
 717         client->irq = info->irq;
 718         if (!client->irq)
 719                 client->irq = i2c_dev_irq_from_resources(info->resources,
 720                                                          info->num_resources);
 721
 722         strlcpy(client->name, info->type, sizeof(client->name));
 723
 724         status = i2c_check_addr_validity(client->addr, client->flags);
 725         if (status) {
 726                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 727                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 728                 goto out_err_silent;
 729         }
 730
 731         /* Check for address business */
 732         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 733         if (status)
 734                 goto out_err;
 735
 736         client->dev.parent = &client->adapter->dev;
 737         client->dev.bus = &i2c_bus_type;
 738         client->dev.type = &i2c_client_type;
 739         client->dev.of_node = info->of_node;
 740         client->dev.fwnode = info->fwnode;
 741
 742         i2c_dev_set_name(adap, client, info);
 743
 744         if (info->properties) {
 745                 status = device_add_properties(&client->dev, info->properties);
 746                 if (status) {
 747                         dev_err(&adap->dev,
 748                                 "Failed to add properties to client %s: %d\n",
 749                                 client->name, status);
 750                         goto out_err;
 751                 }
 752         }
 753
 754         status = device_register(&client->dev);
 755         if (status)
 756                 goto out_free_props;
 757
 758         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 759                 client->name, dev_name(&client->dev));
 760
 761         return client;
 762
 763 out_free_props:
 764         if (info->properties)
 765                 device_remove_properties(&client->dev);
 766 out_err:
 767         dev_err(&adap->dev,
 768                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 769                 client->name, client->addr, status);
 770 out_err_silent:
 771         kfree(client);
 772         return NULL;
 773 }
 774 EXPORT_SYMBOL_GPL(i2c_new_device);
 775
 776
 777 /**
 778  * i2c_unregister_device - reverse effect of i2c_new_device()
 779  * @client: value returned from i2c_new_device()
 780  * Context: can sleep
 781  */
 782 void i2c_unregister_device(struct i2c_client *client)
 783 {
 784         if (!client)
 785                 return;
 786
 787         if (client->dev.of_node) {
 788                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 789                 of_node_put(client->dev.of_node);
 790         }
 791
 792         if (ACPI_COMPANION(&client->dev))
 793                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 794         device_unregister(&client->dev);
 795 }
 796 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 797
 798
 799 static const struct i2c_device_id dummy_id[] = {
 800         { "dummy", 0 },
 801         { },
 802 };
 803
 804 static int dummy_probe(struct i2c_client *client,
 805                        const struct i2c_device_id *id)
 806 {
 807         return 0;
 808 }
 809
 810 static int dummy_remove(struct i2c_client *client)
 811 {
 812         return 0;
 813 }
 814
 815 static struct i2c_driver dummy_driver = {
 816         .driver.name    = "dummy",
 817         .probe          = dummy_probe,
 818         .remove         = dummy_remove,
 819         .id_table       = dummy_id,
 820 };
 821
 822 /**
 823  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 824  * @adapter: the adapter managing the device
 825  * @address: seven bit address to be used
 826  * Context: can sleep
 827  *
 828  * This returns an I2C client bound to the "dummy" driver, intended for use
 829  * with devices that consume multiple addresses.  Examples of such chips
 830  * include various EEPROMS (like 24c04 and 24c08 models).
 831  *
 832  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 833  * except i2c_transfer() need a client handle; the dummy will be that handle.
 834  * And second, this prevents the specified address from being bound to a
 835  * different driver.
 836  *
 837  * This returns the new i2c client, which should be saved for later use with
 838  * i2c_unregister_device(); or NULL to indicate an error.
 839  */
 840 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 841 {
 842         struct i2c_board_info info = {
 843                 I2C_BOARD_INFO("dummy", address),
 844         };
 845
 846         return i2c_new_device(adapter, &info);
 847 }
 848 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 849
 850 /**
 851  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 852  * and create the associated device
 853  * @client: Handle to the primary client
 854  * @name: Handle to specify which secondary address to get
 855  * @default_addr: Used as a fallback if no secondary address was specified
 856  * Context: can sleep
 857  *
 858  * I2C clients can be composed of multiple I2C slaves bound together in a single
 859  * component. The I2C client driver then binds to the master I2C slave and needs
 860  * to create I2C dummy clients to communicate with all the other slaves.
 861  *
 862  * This function creates and returns an I2C dummy client whose I2C address is
 863  * retrieved from the platform firmware based on the given slave name. If no
 864  * address is specified by the firmware default_addr is used.
 865  *
 866  * On DT-based platforms the address is retrieved from the "reg" property entry
 867  * cell whose "reg-names" value matches the slave name.
 868  *
 869  * This returns the new i2c client, which should be saved for later use with
 870  * i2c_unregister_device(); or NULL to indicate an error.
 871  */
 872 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 873                                                 const char *name,
 874                                                 u16 default_addr)
 875 {
 876         struct device_node *np = client->dev.of_node;
 877         u32 addr = default_addr;
 878         int i;
 879
 880         if (np) {
 881                 i = of_property_match_string(np, "reg-names", name);
 882                 if (i >= 0)
 883                         of_property_read_u32_index(np, "reg", i, &addr);
 884         }
 885
 886         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 887         return i2c_new_dummy(client->adapter, addr);
 888 }
 889 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 890
 891 /* ------------------------------------------------------------------------- */
 892
 893 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 894
 895 static void i2c_adapter_dev_release(struct device *dev)
 896 {
 897         struct i2c_adapter *adap = to_i2c_adapter(dev);
 898         complete(&adap->dev_released);
 899 }
 900
 901 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 902 {
 903         unsigned int depth = 0;
 904
 905         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 906                 depth++;
 907
 908         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 909                   "adapter depth exceeds lockdep subclass limit\n");
 910
 911         return depth;
 912 }
 913 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 914
 915 /*
 916  * Let users instantiate I2C devices through sysfs. This can be used when
 917  * platform initialization code doesn't contain the proper data for
 918  * whatever reason. Also useful for drivers that do device detection and
 919  * detection fails, either because the device uses an unexpected address,
 920  * or this is a compatible device with different ID register values.
 921  *
 922  * Parameter checking may look overzealous, but we really don't want
 923  * the user to provide incorrect parameters.
 924  */
 925 static ssize_t
 926 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 927                      const char *buf, size_t count)
 928 {
 929         struct i2c_adapter *adap = to_i2c_adapter(dev);
 930         struct i2c_board_info info;
 931         struct i2c_client *client;
 932         char *blank, end;
 933         int res;
 934
 935         memset(&info, 0, sizeof(struct i2c_board_info));
 936
 937         blank = strchr(buf, ' ');
 938         if (!blank) {
 939                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 940                 return -EINVAL;
 941         }
 942         if (blank - buf > I2C_NAME_SIZE - 1) {
 943                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 944                 return -EINVAL;
 945         }
 946         memcpy(info.type, buf, blank - buf);
 947
 948         /* Parse remaining parameters, reject extra parameters */
 949         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 950         if (res < 1) {
 951                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 952                 return -EINVAL;
 953         }
 954         if (res > 1  && end != '\n') {
 955                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 956                 return -EINVAL;
 957         }
 958
 959         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 960                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 961                 info.flags |= I2C_CLIENT_TEN;
 962         }
 963
 964         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 965                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 966                 info.flags |= I2C_CLIENT_SLAVE;
 967         }
 968
 969         client = i2c_new_device(adap, &info);
 970         if (!client)
 971                 return -EINVAL;
 972
 973         /* Keep track of the added device */
 974         mutex_lock(&adap->userspace_clients_lock);
 975         list_add_tail(&client->detected, &adap->userspace_clients);
 976         mutex_unlock(&adap->userspace_clients_lock);
 977         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 978                  info.type, info.addr);
 979
 980         return count;
 981 }
 982 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
 983
 984 /*
 985  * And of course let the users delete the devices they instantiated, if
 986  * they got it wrong. This interface can only be used to delete devices
 987  * instantiated by i2c_sysfs_new_device above. This guarantees that we
 988  * don't delete devices to which some kernel code still has references.
 989  *
 990  * Parameter checking may look overzealous, but we really don't want
 991  * the user to delete the wrong device.
 992  */
 993 static ssize_t
 994 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
 995                         const char *buf, size_t count)
 996 {
 997         struct i2c_adapter *adap = to_i2c_adapter(dev);
 998         struct i2c_client *client, *next;
 999         unsigned short addr;
1000         char end;
1001         int res;
1002
1003         /* Parse parameters, reject extra parameters */
1004         res = sscanf(buf, "%hi%c", &addr, &end);
1005         if (res < 1) {
1006                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1007                 return -EINVAL;
1008         }
1009         if (res > 1  && end != '\n') {
1010                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1011                 return -EINVAL;
1012         }
1013
1014         /* Make sure the device was added through sysfs */
1015         res = -ENOENT;
1016         mutex_lock_nested(&adap->userspace_clients_lock,
1017                           i2c_adapter_depth(adap));
1018         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1019                                  detected) {
1020                 if (i2c_encode_flags_to_addr(client) == addr) {
1021                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1022                                  "delete_device", client->name, client->addr);
1023
1024                         list_del(&client->detected);
1025                         i2c_unregister_device(client);
1026                         res = count;
1027                         break;
1028                 }
1029         }
1030         mutex_unlock(&adap->userspace_clients_lock);
1031
1032         if (res < 0)
1033                 dev_err(dev, "%s: Can't find device in list\n",
1034                         "delete_device");
1035         return res;
1036 }
1037 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1038                                    i2c_sysfs_delete_device);
1039
1040 static struct attribute *i2c_adapter_attrs[] = {
1041         &dev_attr_name.attr,
1042         &dev_attr_new_device.attr,
1043         &dev_attr_delete_device.attr,
1044         NULL
1045 };
1046 ATTRIBUTE_GROUPS(i2c_adapter);
1047
1048 struct device_type i2c_adapter_type = {
1049         .groups         = i2c_adapter_groups,
1050         .release        = i2c_adapter_dev_release,
1051 };
1052 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1053
1054 /**
1055  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1056  * @dev: device, probably from some driver model iterator
1057  *
1058  * When traversing the driver model tree, perhaps using driver model
1059  * iterators like @device_for_each_child(), you can't assume very much
1060  * about the nodes you find.  Use this function to avoid oopses caused
1061  * by wrongly treating some non-I2C device as an i2c_adapter.
1062  */
1063 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1064 {
1065         return (dev->type == &i2c_adapter_type)
1066                         ? to_i2c_adapter(dev)
1067                         : NULL;
1068 }
1069 EXPORT_SYMBOL(i2c_verify_adapter);
1070
1071 #ifdef CONFIG_I2C_COMPAT
1072 static struct class_compat *i2c_adapter_compat_class;
1073 #endif
1074
1075 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1076 {
1077         struct i2c_devinfo      *devinfo;
1078
1079         down_read(&__i2c_board_lock);
1080         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1081                 if (devinfo->busnum == adapter->nr
1082                                 && !i2c_new_device(adapter,
1083                                                 &devinfo->board_info))
1084                         dev_err(&adapter->dev,
1085                                 "Can't create device at 0x%02x\n",
1086                                 devinfo->board_info.addr);
1087         }
1088         up_read(&__i2c_board_lock);
1089 }
1090
1091 static int i2c_do_add_adapter(struct i2c_driver *driver,
1092                               struct i2c_adapter *adap)
1093 {
1094         /* Detect supported devices on that bus, and instantiate them */
1095         i2c_detect(adap, driver);
1096
1097         /* Let legacy drivers scan this bus for matching devices */
1098         if (driver->attach_adapter) {
1099                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1100                          driver->driver.name);
1101                 dev_warn(&adap->dev,
1102                          "Please use another way to instantiate your i2c_client\n");
1103                 /* We ignore the return code; if it fails, too bad */
1104                 driver->attach_adapter(adap);
1105         }
1106         return 0;
1107 }
1108
1109 static int __process_new_adapter(struct device_driver *d, void *data)
1110 {
1111         return i2c_do_add_adapter(to_i2c_driver(d), data);
1112 }
1113
1114 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1115         .lock_bus =    i2c_adapter_lock_bus,
1116         .trylock_bus = i2c_adapter_trylock_bus,
1117         .unlock_bus =  i2c_adapter_unlock_bus,
1118 };
1119
1120 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1121 {
1122         struct irq_domain *domain = adap->host_notify_domain;
1123         irq_hw_number_t hwirq;
1124
1125         if (!domain)
1126                 return;
1127
1128         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1129                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1130
1131         irq_domain_remove(domain);
1132         adap->host_notify_domain = NULL;
1133 }
1134
1135 static int i2c_host_notify_irq_map(struct irq_domain *h,
1136                                           unsigned int virq,
1137                                           irq_hw_number_t hw_irq_num)
1138 {
1139         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1140
1141         return 0;
1142 }
1143
1144 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1145         .map = i2c_host_notify_irq_map,
1146 };
1147
1148 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1149 {
1150         struct irq_domain *domain;
1151
1152         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1153                 return 0;
1154
1155         domain = irq_domain_create_linear(adap->dev.fwnode,
1156                                           I2C_ADDR_7BITS_COUNT,
1157                                           &i2c_host_notify_irq_ops, adap);
1158         if (!domain)
1159                 return -ENOMEM;
1160
1161         adap->host_notify_domain = domain;
1162
1163         return 0;
1164 }
1165
1166 /**
1167  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1168  * I2C client.
1169  * @adap: the adapter
1170  * @addr: the I2C address of the notifying device
1171  * Context: can't sleep
1172  *
1173  * Helper function to be called from an I2C bus driver's interrupt
1174  * handler. It will schedule the Host Notify IRQ.
1175  */
1176 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1177 {
1178         int irq;
1179
1180         if (!adap)
1181                 return -EINVAL;
1182
1183         irq = irq_find_mapping(adap->host_notify_domain, addr);
1184         if (irq <= 0)
1185                 return -ENXIO;
1186
1187         generic_handle_irq(irq);
1188
1189         return 0;
1190 }
1191 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1192
1193 static int i2c_register_adapter(struct i2c_adapter *adap)
1194 {
1195         int res = -EINVAL;
1196
1197         /* Can't register until after driver model init */
1198         if (WARN_ON(!is_registered)) {
1199                 res = -EAGAIN;
1200                 goto out_list;
1201         }
1202
1203         /* Sanity checks */
1204         if (WARN(!adap->name[0], "i2c adapter has no name"))
1205                 goto out_list;
1206
1207         if (!adap->algo) {
1208                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1209                 goto out_list;
1210         }
1211
1212         if (!adap->lock_ops)
1213                 adap->lock_ops = &i2c_adapter_lock_ops;
1214
1215         rt_mutex_init(&adap->bus_lock);
1216         rt_mutex_init(&adap->mux_lock);
1217         mutex_init(&adap->userspace_clients_lock);
1218         INIT_LIST_HEAD(&adap->userspace_clients);
1219
1220         /* Set default timeout to 1 second if not already set */
1221         if (adap->timeout == 0)
1222                 adap->timeout = HZ;
1223
1224         /* register soft irqs for Host Notify */
1225         res = i2c_setup_host_notify_irq_domain(adap);
1226         if (res) {
1227                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1228                        adap->name, res);
1229                 goto out_list;
1230         }
1231
1232         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1233         adap->dev.bus = &i2c_bus_type;
1234         adap->dev.type = &i2c_adapter_type;
1235         res = device_register(&adap->dev);
1236         if (res) {
1237                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1238                 goto out_list;
1239         }
1240
1241         res = of_i2c_setup_smbus_alert(adap);
1242         if (res)
1243                 goto out_reg;
1244
1245         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1246
1247         pm_runtime_no_callbacks(&adap->dev);
1248         pm_suspend_ignore_children(&adap->dev, true);
1249         pm_runtime_enable(&adap->dev);
1250
1251 #ifdef CONFIG_I2C_COMPAT
1252         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1253                                        adap->dev.parent);
1254         if (res)
1255                 dev_warn(&adap->dev,
1256                          "Failed to create compatibility class link\n");
1257 #endif
1258
1259         i2c_init_recovery(adap);
1260
1261         /* create pre-declared device nodes */
1262         of_i2c_register_devices(adap);
1263         i2c_acpi_register_devices(adap);
1264         i2c_acpi_install_space_handler(adap);
1265
1266         if (adap->nr < __i2c_first_dynamic_bus_num)
1267                 i2c_scan_static_board_info(adap);
1268
1269         /* Notify drivers */
1270         mutex_lock(&core_lock);
1271         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1272         mutex_unlock(&core_lock);
1273
1274         return 0;
1275
1276 out_reg:
1277         init_completion(&adap->dev_released);
1278         device_unregister(&adap->dev);
1279         wait_for_completion(&adap->dev_released);
1280 out_list:
1281         mutex_lock(&core_lock);
1282         idr_remove(&i2c_adapter_idr, adap->nr);
1283         mutex_unlock(&core_lock);
1284         return res;
1285 }
1286
1287 /**
1288  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1289  * @adap: the adapter to register (with adap->nr initialized)
1290  * Context: can sleep
1291  *
1292  * See i2c_add_numbered_adapter() for details.
1293  */
1294 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1295 {
1296         int id;
1297
1298         mutex_lock(&core_lock);
1299         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1300         mutex_unlock(&core_lock);
1301         if (WARN(id < 0, "couldn't get idr"))
1302                 return id == -ENOSPC ? -EBUSY : id;
1303
1304         return i2c_register_adapter(adap);
1305 }
1306
1307 /**
1308  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1309  * @adapter: the adapter to add
1310  * Context: can sleep
1311  *
1312  * This routine is used to declare an I2C adapter when its bus number
1313  * doesn't matter or when its bus number is specified by an dt alias.
1314  * Examples of bases when the bus number doesn't matter: I2C adapters
1315  * dynamically added by USB links or PCI plugin cards.
1316  *
1317  * When this returns zero, a new bus number was allocated and stored
1318  * in adap->nr, and the specified adapter became available for clients.
1319  * Otherwise, a negative errno value is returned.
1320  */
1321 int i2c_add_adapter(struct i2c_adapter *adapter)
1322 {
1323         struct device *dev = &adapter->dev;
1324         int id;
1325
1326         if (dev->of_node) {
1327                 id = of_alias_get_id(dev->of_node, "i2c");
1328                 if (id >= 0) {
1329                         adapter->nr = id;
1330                         return __i2c_add_numbered_adapter(adapter);
1331                 }
1332         }
1333
1334         mutex_lock(&core_lock);
1335         id = idr_alloc(&i2c_adapter_idr, adapter,
1336                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1337         mutex_unlock(&core_lock);
1338         if (WARN(id < 0, "couldn't get idr"))
1339                 return id;
1340
1341         adapter->nr = id;
1342
1343         return i2c_register_adapter(adapter);
1344 }
1345 EXPORT_SYMBOL(i2c_add_adapter);
1346
1347 /**
1348  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1349  * @adap: the adapter to register (with adap->nr initialized)
1350  * Context: can sleep
1351  *
1352  * This routine is used to declare an I2C adapter when its bus number
1353  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1354  * or otherwise built in to the system's mainboard, and where i2c_board_info
1355  * is used to properly configure I2C devices.
1356  *
1357  * If the requested bus number is set to -1, then this function will behave
1358  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1359  *
1360  * If no devices have pre-been declared for this bus, then be sure to
1361  * register the adapter before any dynamically allocated ones.  Otherwise
1362  * the required bus ID may not be available.
1363  *
1364  * When this returns zero, the specified adapter became available for
1365  * clients using the bus number provided in adap->nr.  Also, the table
1366  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1367  * and the appropriate driver model device nodes are created.  Otherwise, a
1368  * negative errno value is returned.
1369  */
1370 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1371 {
1372         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1373                 return i2c_add_adapter(adap);
1374
1375         return __i2c_add_numbered_adapter(adap);
1376 }
1377 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1378
1379 static void i2c_do_del_adapter(struct i2c_driver *driver,
1380                               struct i2c_adapter *adapter)
1381 {
1382         struct i2c_client *client, *_n;
1383
1384         /* Remove the devices we created ourselves as the result of hardware
1385          * probing (using a driver's detect method) */
1386         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1387                 if (client->adapter == adapter) {
1388                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1389                                 client->name, client->addr);
1390                         list_del(&client->detected);
1391                         i2c_unregister_device(client);
1392                 }
1393         }
1394 }
1395
1396 static int __unregister_client(struct device *dev, void *dummy)
1397 {
1398         struct i2c_client *client = i2c_verify_client(dev);
1399         if (client && strcmp(client->name, "dummy"))
1400                 i2c_unregister_device(client);
1401         return 0;
1402 }
1403
1404 static int __unregister_dummy(struct device *dev, void *dummy)
1405 {
1406         struct i2c_client *client = i2c_verify_client(dev);
1407         i2c_unregister_device(client);
1408         return 0;
1409 }
1410
1411 static int __process_removed_adapter(struct device_driver *d, void *data)
1412 {
1413         i2c_do_del_adapter(to_i2c_driver(d), data);
1414         return 0;
1415 }
1416
1417 /**
1418  * i2c_del_adapter - unregister I2C adapter
1419  * @adap: the adapter being unregistered
1420  * Context: can sleep
1421  *
1422  * This unregisters an I2C adapter which was previously registered
1423  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1424  */
1425 void i2c_del_adapter(struct i2c_adapter *adap)
1426 {
1427         struct i2c_adapter *found;
1428         struct i2c_client *client, *next;
1429
1430         /* First make sure that this adapter was ever added */
1431         mutex_lock(&core_lock);
1432         found = idr_find(&i2c_adapter_idr, adap->nr);
1433         mutex_unlock(&core_lock);
1434         if (found != adap) {
1435                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1436                 return;
1437         }
1438
1439         i2c_acpi_remove_space_handler(adap);
1440         /* Tell drivers about this removal */
1441         mutex_lock(&core_lock);
1442         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1443                                __process_removed_adapter);
1444         mutex_unlock(&core_lock);
1445
1446         /* Remove devices instantiated from sysfs */
1447         mutex_lock_nested(&adap->userspace_clients_lock,
1448                           i2c_adapter_depth(adap));
1449         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1450                                  detected) {
1451                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1452                         client->addr);
1453                 list_del(&client->detected);
1454                 i2c_unregister_device(client);
1455         }
1456         mutex_unlock(&adap->userspace_clients_lock);
1457
1458         /* Detach any active clients. This can't fail, thus we do not
1459          * check the returned value. This is a two-pass process, because
1460          * we can't remove the dummy devices during the first pass: they
1461          * could have been instantiated by real devices wishing to clean
1462          * them up properly, so we give them a chance to do that first. */
1463         device_for_each_child(&adap->dev, NULL, __unregister_client);
1464         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1465
1466 #ifdef CONFIG_I2C_COMPAT
1467         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1468                                  adap->dev.parent);
1469 #endif
1470
1471         /* device name is gone after device_unregister */
1472         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1473
1474         pm_runtime_disable(&adap->dev);
1475
1476         i2c_host_notify_irq_teardown(adap);
1477
1478         /* wait until all references to the device are gone
1479          *
1480          * FIXME: This is old code and should ideally be replaced by an
1481          * alternative which results in decoupling the lifetime of the struct
1482          * device from the i2c_adapter, like spi or netdev do. Any solution
1483          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1484          */
1485         init_completion(&adap->dev_released);
1486         device_unregister(&adap->dev);
1487         wait_for_completion(&adap->dev_released);
1488
1489         /* free bus id */
1490         mutex_lock(&core_lock);
1491         idr_remove(&i2c_adapter_idr, adap->nr);
1492         mutex_unlock(&core_lock);
1493
1494         /* Clear the device structure in case this adapter is ever going to be
1495            added again */
1496         memset(&adap->dev, 0, sizeof(adap->dev));
1497 }
1498 EXPORT_SYMBOL(i2c_del_adapter);
1499
1500 /**
1501  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1502  * @dev: The device to scan for I2C timing properties
1503  * @t: the i2c_timings struct to be filled with values
1504  * @use_defaults: bool to use sane defaults derived from the I2C specification
1505  *                when properties are not found, otherwise use 0
1506  *
1507  * Scan the device for the generic I2C properties describing timing parameters
1508  * for the signal and fill the given struct with the results. If a property was
1509  * not found and use_defaults was true, then maximum timings are assumed which
1510  * are derived from the I2C specification. If use_defaults is not used, the
1511  * results will be 0, so drivers can apply their own defaults later. The latter
1512  * is mainly intended for avoiding regressions of existing drivers which want
1513  * to switch to this function. New drivers almost always should use the defaults.
1514  */
1515
1516 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1517 {
1518         int ret;
1519
1520         memset(t, 0, sizeof(*t));
1521
1522         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1523         if (ret && use_defaults)
1524                 t->bus_freq_hz = 100000;
1525
1526         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1527         if (ret && use_defaults) {
1528                 if (t->bus_freq_hz <= 100000)
1529                         t->scl_rise_ns = 1000;
1530                 else if (t->bus_freq_hz <= 400000)
1531                         t->scl_rise_ns = 300;
1532                 else
1533                         t->scl_rise_ns = 120;
1534         }
1535
1536         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1537         if (ret && use_defaults) {
1538                 if (t->bus_freq_hz <= 400000)
1539                         t->scl_fall_ns = 300;
1540                 else
1541                         t->scl_fall_ns = 120;
1542         }
1543
1544         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1545
1546         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1547         if (ret && use_defaults)
1548                 t->sda_fall_ns = t->scl_fall_ns;
1549 }
1550 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1551
1552 /* ------------------------------------------------------------------------- */
1553
1554 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1555 {
1556         int res;
1557
1558         mutex_lock(&core_lock);
1559         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1560         mutex_unlock(&core_lock);
1561
1562         return res;
1563 }
1564 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1565
1566 static int __process_new_driver(struct device *dev, void *data)
1567 {
1568         if (dev->type != &i2c_adapter_type)
1569                 return 0;
1570         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1571 }
1572
1573 /*
1574  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1575  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1576  */
1577
1578 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1579 {
1580         int res;
1581
1582         /* Can't register until after driver model init */
1583         if (WARN_ON(!is_registered))
1584                 return -EAGAIN;
1585
1586         /* add the driver to the list of i2c drivers in the driver core */
1587         driver->driver.owner = owner;
1588         driver->driver.bus = &i2c_bus_type;
1589         INIT_LIST_HEAD(&driver->clients);
1590
1591         /* When registration returns, the driver core
1592          * will have called probe() for all matching-but-unbound devices.
1593          */
1594         res = driver_register(&driver->driver);
1595         if (res)
1596                 return res;
1597
1598         pr_debug("driver [%s] registered\n", driver->driver.name);
1599
1600         /* Walk the adapters that are already present */
1601         i2c_for_each_dev(driver, __process_new_driver);
1602
1603         return 0;
1604 }
1605 EXPORT_SYMBOL(i2c_register_driver);
1606
1607 static int __process_removed_driver(struct device *dev, void *data)
1608 {
1609         if (dev->type == &i2c_adapter_type)
1610                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1611         return 0;
1612 }
1613
1614 /**
1615  * i2c_del_driver - unregister I2C driver
1616  * @driver: the driver being unregistered
1617  * Context: can sleep
1618  */
1619 void i2c_del_driver(struct i2c_driver *driver)
1620 {
1621         i2c_for_each_dev(driver, __process_removed_driver);
1622
1623         driver_unregister(&driver->driver);
1624         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1625 }
1626 EXPORT_SYMBOL(i2c_del_driver);
1627
1628 /* ------------------------------------------------------------------------- */
1629
1630 /**
1631  * i2c_use_client - increments the reference count of the i2c client structure
1632  * @client: the client being referenced
1633  *
1634  * Each live reference to a client should be refcounted. The driver model does
1635  * that automatically as part of driver binding, so that most drivers don't
1636  * need to do this explicitly: they hold a reference until they're unbound
1637  * from the device.
1638  *
1639  * A pointer to the client with the incremented reference counter is returned.
1640  */
1641 struct i2c_client *i2c_use_client(struct i2c_client *client)
1642 {
1643         if (client && get_device(&client->dev))
1644                 return client;
1645         return NULL;
1646 }
1647 EXPORT_SYMBOL(i2c_use_client);
1648
1649 /**
1650  * i2c_release_client - release a use of the i2c client structure
1651  * @client: the client being no longer referenced
1652  *
1653  * Must be called when a user of a client is finished with it.
1654  */
1655 void i2c_release_client(struct i2c_client *client)
1656 {
1657         if (client)
1658                 put_device(&client->dev);
1659 }
1660 EXPORT_SYMBOL(i2c_release_client);
1661
1662 struct i2c_cmd_arg {
1663         unsigned        cmd;
1664         void            *arg;
1665 };
1666
1667 static int i2c_cmd(struct device *dev, void *_arg)
1668 {
1669         struct i2c_client       *client = i2c_verify_client(dev);
1670         struct i2c_cmd_arg      *arg = _arg;
1671         struct i2c_driver       *driver;
1672
1673         if (!client || !client->dev.driver)
1674                 return 0;
1675
1676         driver = to_i2c_driver(client->dev.driver);
1677         if (driver->command)
1678                 driver->command(client, arg->cmd, arg->arg);
1679         return 0;
1680 }
1681
1682 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1683 {
1684         struct i2c_cmd_arg      cmd_arg;
1685
1686         cmd_arg.cmd = cmd;
1687         cmd_arg.arg = arg;
1688         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1689 }
1690 EXPORT_SYMBOL(i2c_clients_command);
1691
1692 static int __init i2c_init(void)
1693 {
1694         int retval;
1695
1696         retval = of_alias_get_highest_id("i2c");
1697
1698         down_write(&__i2c_board_lock);
1699         if (retval >= __i2c_first_dynamic_bus_num)
1700                 __i2c_first_dynamic_bus_num = retval + 1;
1701         up_write(&__i2c_board_lock);
1702
1703         retval = bus_register(&i2c_bus_type);
1704         if (retval)
1705                 return retval;
1706
1707         is_registered = true;
1708
1709 #ifdef CONFIG_I2C_COMPAT
1710         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1711         if (!i2c_adapter_compat_class) {
1712                 retval = -ENOMEM;
1713                 goto bus_err;
1714         }
1715 #endif
1716         retval = i2c_add_driver(&dummy_driver);
1717         if (retval)
1718                 goto class_err;
1719
1720         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1721                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1722         if (IS_ENABLED(CONFIG_ACPI))
1723                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1724
1725         return 0;
1726
1727 class_err:
1728 #ifdef CONFIG_I2C_COMPAT
1729         class_compat_unregister(i2c_adapter_compat_class);
1730 bus_err:
1731 #endif
1732         is_registered = false;
1733         bus_unregister(&i2c_bus_type);
1734         return retval;
1735 }
1736
1737 static void __exit i2c_exit(void)
1738 {
1739         if (IS_ENABLED(CONFIG_ACPI))
1740                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1741         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1742                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1743         i2c_del_driver(&dummy_driver);
1744 #ifdef CONFIG_I2C_COMPAT
1745         class_compat_unregister(i2c_adapter_compat_class);
1746 #endif
1747         bus_unregister(&i2c_bus_type);
1748         tracepoint_synchronize_unregister();
1749 }
1750
1751 /* We must initialize early, because some subsystems register i2c drivers
1752  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1753  */
1754 postcore_initcall(i2c_init);
1755 module_exit(i2c_exit);
1756
1757 /* ----------------------------------------------------
1758  * the functional interface to the i2c busses.
1759  * ----------------------------------------------------
1760  */
1761
1762 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1763 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1764
1765 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1766 {
1767         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1768                             err_msg, msg->addr, msg->len,
1769                             msg->flags & I2C_M_RD ? "read" : "write");
1770         return -EOPNOTSUPP;
1771 }
1772
1773 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1774 {
1775         const struct i2c_adapter_quirks *q = adap->quirks;
1776         int max_num = q->max_num_msgs, i;
1777         bool do_len_check = true;
1778
1779         if (q->flags & I2C_AQ_COMB) {
1780                 max_num = 2;
1781
1782                 /* special checks for combined messages */
1783                 if (num == 2) {
1784                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1785                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1786
1787                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1788                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1789
1790                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1791                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1792
1793                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1794                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1795
1796                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1797                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1798
1799                         do_len_check = false;
1800                 }
1801         }
1802
1803         if (i2c_quirk_exceeded(num, max_num))
1804                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1805
1806         for (i = 0; i < num; i++) {
1807                 u16 len = msgs[i].len;
1808
1809                 if (msgs[i].flags & I2C_M_RD) {
1810                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1811                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1812                 } else {
1813                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1814                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1815                 }
1816         }
1817
1818         return 0;
1819 }
1820
1821 /**
1822  * __i2c_transfer - unlocked flavor of i2c_transfer
1823  * @adap: Handle to I2C bus
1824  * @msgs: One or more messages to execute before STOP is issued to
1825  *      terminate the operation; each message begins with a START.
1826  * @num: Number of messages to be executed.
1827  *
1828  * Returns negative errno, else the number of messages executed.
1829  *
1830  * Adapter lock must be held when calling this function. No debug logging
1831  * takes place. adap->algo->master_xfer existence isn't checked.
1832  */
1833 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1834 {
1835         unsigned long orig_jiffies;
1836         int ret, try;
1837
1838         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1839                 return -EOPNOTSUPP;
1840
1841         /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1842          * enabled.  This is an efficient way of keeping the for-loop from
1843          * being executed when not needed.
1844          */
1845         if (static_key_false(&i2c_trace_msg)) {
1846                 int i;
1847                 for (i = 0; i < num; i++)
1848                         if (msgs[i].flags & I2C_M_RD)
1849                                 trace_i2c_read(adap, &msgs[i], i);
1850                         else
1851                                 trace_i2c_write(adap, &msgs[i], i);
1852         }
1853
1854         /* Retry automatically on arbitration loss */
1855         orig_jiffies = jiffies;
1856         for (ret = 0, try = 0; try <= adap->retries; try++) {
1857                 ret = adap->algo->master_xfer(adap, msgs, num);
1858                 if (ret != -EAGAIN)
1859                         break;
1860                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1861                         break;
1862         }
1863
1864         if (static_key_false(&i2c_trace_msg)) {
1865                 int i;
1866                 for (i = 0; i < ret; i++)
1867                         if (msgs[i].flags & I2C_M_RD)
1868                                 trace_i2c_reply(adap, &msgs[i], i);
1869                 trace_i2c_result(adap, i, ret);
1870         }
1871
1872         return ret;
1873 }
1874 EXPORT_SYMBOL(__i2c_transfer);
1875
1876 /**
1877  * i2c_transfer - execute a single or combined I2C message
1878  * @adap: Handle to I2C bus
1879  * @msgs: One or more messages to execute before STOP is issued to
1880  *      terminate the operation; each message begins with a START.
1881  * @num: Number of messages to be executed.
1882  *
1883  * Returns negative errno, else the number of messages executed.
1884  *
1885  * Note that there is no requirement that each message be sent to
1886  * the same slave address, although that is the most common model.
1887  */
1888 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1889 {
1890         int ret;
1891
1892         /* REVISIT the fault reporting model here is weak:
1893          *
1894          *  - When we get an error after receiving N bytes from a slave,
1895          *    there is no way to report "N".
1896          *
1897          *  - When we get a NAK after transmitting N bytes to a slave,
1898          *    there is no way to report "N" ... or to let the master
1899          *    continue executing the rest of this combined message, if
1900          *    that's the appropriate response.
1901          *
1902          *  - When for example "num" is two and we successfully complete
1903          *    the first message but get an error part way through the
1904          *    second, it's unclear whether that should be reported as
1905          *    one (discarding status on the second message) or errno
1906          *    (discarding status on the first one).
1907          */
1908
1909         if (adap->algo->master_xfer) {
1910 #ifdef DEBUG
1911                 for (ret = 0; ret < num; ret++) {
1912                         dev_dbg(&adap->dev,
1913                                 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1914                                 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1915                                 msgs[ret].addr, msgs[ret].len,
1916                                 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1917                 }
1918 #endif
1919
1920                 if (in_atomic() || irqs_disabled()) {
1921                         ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1922                         if (!ret)
1923                                 /* I2C activity is ongoing. */
1924                                 return -EAGAIN;
1925                 } else {
1926                         i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1927                 }
1928
1929                 ret = __i2c_transfer(adap, msgs, num);
1930                 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1931
1932                 return ret;
1933         } else {
1934                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1935                 return -EOPNOTSUPP;
1936         }
1937 }
1938 EXPORT_SYMBOL(i2c_transfer);
1939
1940 /**
1941  * i2c_transfer_buffer_flags - issue a single I2C message transferring data
1942  *                             to/from a buffer
1943  * @client: Handle to slave device
1944  * @buf: Where the data is stored
1945  * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
1946  * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
1947  *
1948  * Returns negative errno, or else the number of bytes transferred.
1949  */
1950 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
1951                               int count, u16 flags)
1952 {
1953         int ret;
1954         struct i2c_msg msg = {
1955                 .addr = client->addr,
1956                 .flags = flags | (client->flags & I2C_M_TEN),
1957                 .len = count,
1958                 .buf = buf,
1959         };
1960
1961         ret = i2c_transfer(client->adapter, &msg, 1);
1962
1963         /*
1964          * If everything went ok (i.e. 1 msg transferred), return #bytes
1965          * transferred, else error code.
1966          */
1967         return (ret == 1) ? count : ret;
1968 }
1969 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
1970
1971 /* ----------------------------------------------------
1972  * the i2c address scanning function
1973  * Will not work for 10-bit addresses!
1974  * ----------------------------------------------------
1975  */
1976
1977 /*
1978  * Legacy default probe function, mostly relevant for SMBus. The default
1979  * probe method is a quick write, but it is known to corrupt the 24RF08
1980  * EEPROMs due to a state machine bug, and could also irreversibly
1981  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1982  * we use a short byte read instead. Also, some bus drivers don't implement
1983  * quick write, so we fallback to a byte read in that case too.
1984  * On x86, there is another special case for FSC hardware monitoring chips,
1985  * which want regular byte reads (address 0x73.) Fortunately, these are the
1986  * only known chips using this I2C address on PC hardware.
1987  * Returns 1 if probe succeeded, 0 if not.
1988  */
1989 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1990 {
1991         int err;
1992         union i2c_smbus_data dummy;
1993
1994 #ifdef CONFIG_X86
1995         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1996          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1997                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1998                                      I2C_SMBUS_BYTE_DATA, &dummy);
1999         else
2000 #endif
2001         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2002          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2003                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2004                                      I2C_SMBUS_QUICK, NULL);
2005         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2006                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2007                                      I2C_SMBUS_BYTE, &dummy);
2008         else {
2009                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2010                          addr);
2011                 err = -EOPNOTSUPP;
2012         }
2013
2014         return err >= 0;
2015 }
2016
2017 static int i2c_detect_address(struct i2c_client *temp_client,
2018                               struct i2c_driver *driver)
2019 {
2020         struct i2c_board_info info;
2021         struct i2c_adapter *adapter = temp_client->adapter;
2022         int addr = temp_client->addr;
2023         int err;
2024
2025         /* Make sure the address is valid */
2026         err = i2c_check_7bit_addr_validity_strict(addr);
2027         if (err) {
2028                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2029                          addr);
2030                 return err;
2031         }
2032
2033         /* Skip if already in use (7 bit, no need to encode flags) */
2034         if (i2c_check_addr_busy(adapter, addr))
2035                 return 0;
2036
2037         /* Make sure there is something at this address */
2038         if (!i2c_default_probe(adapter, addr))
2039                 return 0;
2040
2041         /* Finally call the custom detection function */
2042         memset(&info, 0, sizeof(struct i2c_board_info));
2043         info.addr = addr;
2044         err = driver->detect(temp_client, &info);
2045         if (err) {
2046                 /* -ENODEV is returned if the detection fails. We catch it
2047                    here as this isn't an error. */
2048                 return err == -ENODEV ? 0 : err;
2049         }
2050
2051         /* Consistency check */
2052         if (info.type[0] == '\0') {
2053                 dev_err(&adapter->dev,
2054                         "%s detection function provided no name for 0x%x\n",
2055                         driver->driver.name, addr);
2056         } else {
2057                 struct i2c_client *client;
2058
2059                 /* Detection succeeded, instantiate the device */
2060                 if (adapter->class & I2C_CLASS_DEPRECATED)
2061                         dev_warn(&adapter->dev,
2062                                 "This adapter will soon drop class based instantiation of devices. "
2063                                 "Please make sure client 0x%02x gets instantiated by other means. "
2064                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2065                                 info.addr);
2066
2067                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2068                         info.type, info.addr);
2069                 client = i2c_new_device(adapter, &info);
2070                 if (client)
2071                         list_add_tail(&client->detected, &driver->clients);
2072                 else
2073                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2074                                 info.type, info.addr);
2075         }
2076         return 0;
2077 }
2078
2079 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2080 {
2081         const unsigned short *address_list;
2082         struct i2c_client *temp_client;
2083         int i, err = 0;
2084         int adap_id = i2c_adapter_id(adapter);
2085
2086         address_list = driver->address_list;
2087         if (!driver->detect || !address_list)
2088                 return 0;
2089
2090         /* Warn that the adapter lost class based instantiation */
2091         if (adapter->class == I2C_CLASS_DEPRECATED) {
2092                 dev_dbg(&adapter->dev,
2093                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2094                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2095                         driver->driver.name);
2096                 return 0;
2097         }
2098
2099         /* Stop here if the classes do not match */
2100         if (!(adapter->class & driver->class))
2101                 return 0;
2102
2103         /* Set up a temporary client to help detect callback */
2104         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2105         if (!temp_client)
2106                 return -ENOMEM;
2107         temp_client->adapter = adapter;
2108
2109         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2110                 dev_dbg(&adapter->dev,
2111                         "found normal entry for adapter %d, addr 0x%02x\n",
2112                         adap_id, address_list[i]);
2113                 temp_client->addr = address_list[i];
2114                 err = i2c_detect_address(temp_client, driver);
2115                 if (unlikely(err))
2116                         break;
2117         }
2118
2119         kfree(temp_client);
2120         return err;
2121 }
2122
2123 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2124 {
2125         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2126                               I2C_SMBUS_QUICK, NULL) >= 0;
2127 }
2128 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2129
2130 struct i2c_client *
2131 i2c_new_probed_device(struct i2c_adapter *adap,
2132                       struct i2c_board_info *info,
2133                       unsigned short const *addr_list,
2134                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2135 {
2136         int i;
2137
2138         if (!probe)
2139                 probe = i2c_default_probe;
2140
2141         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2142                 /* Check address validity */
2143                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2144                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2145                                  addr_list[i]);
2146                         continue;
2147                 }
2148
2149                 /* Check address availability (7 bit, no need to encode flags) */
2150                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2151                         dev_dbg(&adap->dev,
2152                                 "Address 0x%02x already in use, not probing\n",
2153                                 addr_list[i]);
2154                         continue;
2155                 }
2156
2157                 /* Test address responsiveness */
2158                 if (probe(adap, addr_list[i]))
2159                         break;
2160         }
2161
2162         if (addr_list[i] == I2C_CLIENT_END) {
2163                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2164                 return NULL;
2165         }
2166
2167         info->addr = addr_list[i];
2168         return i2c_new_device(adap, info);
2169 }
2170 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2171
2172 struct i2c_adapter *i2c_get_adapter(int nr)
2173 {
2174         struct i2c_adapter *adapter;
2175
2176         mutex_lock(&core_lock);
2177         adapter = idr_find(&i2c_adapter_idr, nr);
2178         if (!adapter)
2179                 goto exit;
2180
2181         if (try_module_get(adapter->owner))
2182                 get_device(&adapter->dev);
2183         else
2184                 adapter = NULL;
2185
2186  exit:
2187         mutex_unlock(&core_lock);
2188         return adapter;
2189 }
2190 EXPORT_SYMBOL(i2c_get_adapter);
2191
2192 void i2c_put_adapter(struct i2c_adapter *adap)
2193 {
2194         if (!adap)
2195                 return;
2196
2197         put_device(&adap->dev);
2198         module_put(adap->owner);
2199 }
2200 EXPORT_SYMBOL(i2c_put_adapter);
2201
2202 /**
2203  * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2204  * @msg: the message to be checked
2205  * @threshold: the minimum number of bytes for which using DMA makes sense
2206  *
2207  * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2208  *         Or a valid pointer to be used with DMA. After use, release it by
2209  *         calling i2c_release_dma_safe_msg_buf().
2210  *
2211  * This function must only be called from process context!
2212  */
2213 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2214 {
2215         if (msg->len < threshold)
2216                 return NULL;
2217
2218         if (msg->flags & I2C_M_DMA_SAFE)
2219                 return msg->buf;
2220
2221         pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2222                  msg->addr, msg->len);
2223
2224         if (msg->flags & I2C_M_RD)
2225                 return kzalloc(msg->len, GFP_KERNEL);
2226         else
2227                 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2228 }
2229 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2230
2231 /**
2232  * i2c_release_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2233  * @msg: the message to be synced with
2234  * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2235  */
2236 void i2c_release_dma_safe_msg_buf(struct i2c_msg *msg, u8 *buf)
2237 {
2238         if (!buf || buf == msg->buf)
2239                 return;
2240
2241         if (msg->flags & I2C_M_RD)
2242                 memcpy(msg->buf, buf, msg->len);
2243
2244         kfree(buf);
2245 }
2246 EXPORT_SYMBOL_GPL(i2c_release_dma_safe_msg_buf);
2247
2248 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2249 MODULE_DESCRIPTION("I2C-Bus main module");
2250 MODULE_LICENSE("GPL");