linux/drivers/i2c/i2c-core-base.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Linux I2C core
   4 *
   5 * Copyright (C) 1995-99 Simon G. Vogl
   6 *   With some changes from Ky\xC3\xB6sti M\xC3\xA4lkki <kmalkki@cc.hut.fi>
   7 *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   8 *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   9 *
  10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
  11 */
  12
  13#define pr_fmt(fmt) "i2c-core: " fmt
  14
  15#include <dt-bindings/i2c/i2c.h>
  16#include <linux/acpi.h>
  17#include <linux/clk/clk-conf.h>
  18#include <linux/completion.h>
  19#include <linux/delay.h>
  20#include <linux/err.h>
  21#include <linux/errno.h>
  22#include <linux/gpio/consumer.h>
  23#include <linux/i2c.h>
  24#include <linux/i2c-smbus.h>
  25#include <linux/idr.h>
  26#include <linux/init.h>
  27#include <linux/interrupt.h>
  28#include <linux/irqflags.h>
  29#include <linux/jump_label.h>
  30#include <linux/kernel.h>
  31#include <linux/module.h>
  32#include <linux/mutex.h>
  33#include <linux/of_device.h>
  34#include <linux/of.h>
  35#include <linux/of_irq.h>
  36#include <linux/pinctrl/consumer.h>
  37#include <linux/pm_domain.h>
  38#include <linux/pm_runtime.h>
  39#include <linux/pm_wakeirq.h>
  40#include <linux/property.h>
  41#include <linux/rwsem.h>
  42#include <linux/slab.h>
  43
  44#include "i2c-core.h"
  45
  46#define CREATE_TRACE_POINTS
  47#include <trace/events/i2c.h>
  48
  49#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
  50#define I2C_ADDR_OFFSET_SLAVE   0x1000
  51
  52#define I2C_ADDR_7BITS_MAX      0x77
  53#define I2C_ADDR_7BITS_COUNT    (I2C_ADDR_7BITS_MAX + 1)
  54
  55#define I2C_ADDR_DEVICE_ID      0x7c
  56
  57/*
  58 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  59 * deletion of detected devices are serialized
  60 */
  61static DEFINE_MUTEX(core_lock);
  62static DEFINE_IDR(i2c_adapter_idr);
  63
  64static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  65
  66static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
  67static bool is_registered;
  68
  69int i2c_transfer_trace_reg(void)
  70{
  71        static_branch_inc(&i2c_trace_msg_key);
  72        return 0;
  73}
  74
  75void i2c_transfer_trace_unreg(void)
  76{
  77        static_branch_dec(&i2c_trace_msg_key);
  78}
  79
  80const char *i2c_freq_mode_string(u32 bus_freq_hz)
  81{
  82        switch (bus_freq_hz) {
  83        case I2C_MAX_STANDARD_MODE_FREQ:
  84                return "Standard Mode (100 kHz)";
  85        case I2C_MAX_FAST_MODE_FREQ:
  86                return "Fast Mode (400 kHz)";
  87        case I2C_MAX_FAST_MODE_PLUS_FREQ:
  88                return "Fast Mode Plus (1.0 MHz)";
  89        case I2C_MAX_TURBO_MODE_FREQ:
  90                return "Turbo Mode (1.4 MHz)";
  91        case I2C_MAX_HIGH_SPEED_MODE_FREQ:
  92                return "High Speed Mode (3.4 MHz)";
  93        case I2C_MAX_ULTRA_FAST_MODE_FREQ:
  94                return "Ultra Fast Mode (5.0 MHz)";
  95        default:
  96                return "Unknown Mode";
  97        }
  98}
  99EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
 100
 101const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
 102                                                const struct i2c_client *client)
 103{
 104        if (!(id && client))
 105                return NULL;
 106
 107        while (id->name[0]) {
 108                if (strcmp(client->name, id->name) == 0)
 109                        return id;
 110                id++;
 111        }
 112        return NULL;
 113}
 114EXPORT_SYMBOL_GPL(i2c_match_id);
 115
 116static int i2c_device_match(struct device *dev, struct device_driver *drv)
 117{
 118        struct i2c_client       *client = i2c_verify_client(dev);
 119        struct i2c_driver       *driver;
 120
 121
 122        /* Attempt an OF style match */
 123        if (i2c_of_match_device(drv->of_match_table, client))
 124                return 1;
 125
 126        /* Then ACPI style match */
 127        if (acpi_driver_match_device(dev, drv))
 128                return 1;
 129
 130        driver = to_i2c_driver(drv);
 131
 132        /* Finally an I2C match */
 133        if (i2c_match_id(driver->id_table, client))
 134                return 1;
 135
 136        return 0;
 137}
 138
 139static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 140{
 141        struct i2c_client *client = to_i2c_client(dev);
 142        int rc;
 143
 144        rc = of_device_uevent_modalias(dev, env);
 145        if (rc != -ENODEV)
 146                return rc;
 147
 148        rc = acpi_device_uevent_modalias(dev, env);
 149        if (rc != -ENODEV)
 150                return rc;
 151
 152        return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 153}
 154
 155/* i2c bus recovery routines */
 156static int get_scl_gpio_value(struct i2c_adapter *adap)
 157{
 158        return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
 159}
 160
 161static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 162{
 163        gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
 164}
 165
 166static int get_sda_gpio_value(struct i2c_adapter *adap)
 167{
 168        return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
 169}
 170
 171static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
 172{
 173        gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
 174}
 175
 176static int i2c_generic_bus_free(struct i2c_adapter *adap)
 177{
 178        struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 179        int ret = -EOPNOTSUPP;
 180
 181        if (bri->get_bus_free)
 182                ret = bri->get_bus_free(adap);
 183        else if (bri->get_sda)
 184                ret = bri->get_sda(adap);
 185
 186        if (ret < 0)
 187                return ret;
 188
 189        return ret ? 0 : -EBUSY;
 190}
 191
 192/*
 193 * We are generating clock pulses. ndelay() determines durating of clk pulses.
 194 * We will generate clock with rate 100 KHz and so duration of both clock levels
 195 * is: delay in ns = (10^6 / 100) / 2
 196 */
 197#define RECOVERY_NDELAY         5000
 198#define RECOVERY_CLK_CNT        9
 199
 200int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 201{
 202        struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 203        int i = 0, scl = 1, ret = 0;
 204
 205        if (bri->prepare_recovery)
 206                bri->prepare_recovery(adap);
 207        if (bri->pinctrl)
 208                pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
 209
 210        /*
 211         * If we can set SDA, we will always create a STOP to ensure additional
 212         * pulses will do no harm. This is achieved by letting SDA follow SCL
 213         * half a cycle later. Check the 'incomplete_write_byte' fault injector
 214         * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
 215         * here for simplicity.
 216         */
 217        bri->set_scl(adap, scl);
 218        ndelay(RECOVERY_NDELAY);
 219        if (bri->set_sda)
 220                bri->set_sda(adap, scl);
 221        ndelay(RECOVERY_NDELAY / 2);
 222
 223        /*
 224         * By this time SCL is high, as we need to give 9 falling-rising edges
 225         */
 226        while (i++ < RECOVERY_CLK_CNT * 2) {
 227                if (scl) {
 228                        /* SCL shouldn't be low here */
 229                        if (!bri->get_scl(adap)) {
 230                                dev_err(&adap->dev,
 231                                        "SCL is stuck low, exit recovery\n");
 232                                ret = -EBUSY;
 233                                break;
 234                        }
 235                }
 236
 237                scl = !scl;
 238                bri->set_scl(adap, scl);
 239                /* Creating STOP again, see above */
 240                if (scl)  {
 241                        /* Honour minimum tsu:sto */
 242                        ndelay(RECOVERY_NDELAY);
 243                } else {
 244                        /* Honour minimum tf and thd:dat */
 245                        ndelay(RECOVERY_NDELAY / 2);
 246                }
 247                if (bri->set_sda)
 248                        bri->set_sda(adap, scl);
 249                ndelay(RECOVERY_NDELAY / 2);
 250
 251                if (scl) {
 252                        ret = i2c_generic_bus_free(adap);
 253                        if (ret == 0)
 254                                break;
 255                }
 256        }
 257
 258        /* If we can't check bus status, assume recovery worked */
 259        if (ret == -EOPNOTSUPP)
 260                ret = 0;
 261
 262        if (bri->unprepare_recovery)
 263                bri->unprepare_recovery(adap);
 264        if (bri->pinctrl)
 265                pinctrl_select_state(bri->pinctrl, bri->pins_default);
 266
 267        return ret;
 268}
 269EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 270
 271int i2c_recover_bus(struct i2c_adapter *adap)
 272{
 273        if (!adap->bus_recovery_info)
 274                return -EBUSY;
 275
 276        dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 277        return adap->bus_recovery_info->recover_bus(adap);
 278}
 279EXPORT_SYMBOL_GPL(i2c_recover_bus);
 280
 281static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
 282{
 283        struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 284        struct device *dev = &adap->dev;
 285        struct pinctrl *p = bri->pinctrl;
 286
 287        /*
 288         * we can't change states without pinctrl, so remove the states if
 289         * populated
 290         */
 291        if (!p) {
 292                bri->pins_default = NULL;
 293                bri->pins_gpio = NULL;
 294                return;
 295        }
 296
 297        if (!bri->pins_default) {
 298                bri->pins_default = pinctrl_lookup_state(p,
 299                                                         PINCTRL_STATE_DEFAULT);
 300                if (IS_ERR(bri->pins_default)) {
 301                        dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
 302                        bri->pins_default = NULL;
 303                }
 304        }
 305        if (!bri->pins_gpio) {
 306                bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
 307                if (IS_ERR(bri->pins_gpio))
 308                        bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
 309
 310                if (IS_ERR(bri->pins_gpio)) {
 311                        dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
 312                        bri->pins_gpio = NULL;
 313                }
 314        }
 315
 316        /* for pinctrl state changes, we need all the information */
 317        if (bri->pins_default && bri->pins_gpio) {
 318                dev_info(dev, "using pinctrl states for GPIO recovery");
 319        } else {
 320                bri->pinctrl = NULL;
 321                bri->pins_default = NULL;
 322                bri->pins_gpio = NULL;
 323        }
 324}
 325
 326static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
 327{
 328        struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 329        struct device *dev = &adap->dev;
 330        struct gpio_desc *gpiod;
 331        int ret = 0;
 332
 333        /*
 334         * don't touch the recovery information if the driver is not using
 335         * generic SCL recovery
 336         */
 337        if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
 338                return 0;
 339
 340        /*
 341         * pins might be taken as GPIO, so we should inform pinctrl about
 342         * this and move the state to GPIO
 343         */
 344        if (bri->pinctrl)
 345                pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
 346
 347        /*
 348         * if there is incomplete or no recovery information, see if generic
 349         * GPIO recovery is available
 350         */
 351        if (!bri->scl_gpiod) {
 352                gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
 353                if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
 354                        ret  = -EPROBE_DEFER;
 355                        goto cleanup_pinctrl_state;
 356                }
 357                if (!IS_ERR(gpiod)) {
 358                        bri->scl_gpiod = gpiod;
 359                        bri->recover_bus = i2c_generic_scl_recovery;
 360                        dev_info(dev, "using generic GPIOs for recovery\n");
 361                }
 362        }
 363
 364        /* SDA GPIOD line is optional, so we care about DEFER only */
 365        if (!bri->sda_gpiod) {
 366                /*
 367                 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
 368                 * have no effect.
 369                 */
 370                gpiod_direction_output(bri->scl_gpiod, 0);
 371                udelay(10);
 372                gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
 373
 374                /* Wait a bit in case of a SDA glitch, and then release SCL. */
 375                udelay(10);
 376                gpiod_direction_output(bri->scl_gpiod, 1);
 377
 378                if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
 379                        ret = -EPROBE_DEFER;
 380                        goto cleanup_pinctrl_state;
 381                }
 382                if (!IS_ERR(gpiod))
 383                        bri->sda_gpiod = gpiod;
 384        }
 385
 386cleanup_pinctrl_state:
 387        /* change the state of the pins back to their default state */
 388        if (bri->pinctrl)
 389                pinctrl_select_state(bri->pinctrl, bri->pins_default);
 390
 391        return ret;
 392}
 393
 394static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
 395{
 396        i2c_gpio_init_pinctrl_recovery(adap);
 397        return i2c_gpio_init_generic_recovery(adap);
 398}
 399
 400static int i2c_init_recovery(struct i2c_adapter *adap)
 401{
 402        struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 403        bool is_error_level = true;
 404        char *err_str;
 405
 406        if (!bri)
 407                return 0;
 408
 409        if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
 410                return -EPROBE_DEFER;
 411
 412        if (!bri->recover_bus) {
 413                err_str = "no suitable method provided";
 414                is_error_level = false;
 415                goto err;
 416        }
 417
 418        if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
 419                bri->get_scl = get_scl_gpio_value;
 420                bri->set_scl = set_scl_gpio_value;
 421                if (bri->sda_gpiod) {
 422                        bri->get_sda = get_sda_gpio_value;
 423                        /* FIXME: add proper flag instead of '0' once available */
 424                        if (gpiod_get_direction(bri->sda_gpiod) == 0)
 425                                bri->set_sda = set_sda_gpio_value;
 426                }
 427        } else if (bri->recover_bus == i2c_generic_scl_recovery) {
 428                /* Generic SCL recovery */
 429                if (!bri->set_scl || !bri->get_scl) {
 430                        err_str = "no {get|set}_scl() found";
 431                        goto err;
 432                }
 433                if (!bri->set_sda && !bri->get_sda) {
 434                        err_str = "either get_sda() or set_sda() needed";
 435                        goto err;
 436                }
 437        }
 438
 439        return 0;
 440 err:
 441        if (is_error_level)
 442                dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 443        else
 444                dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
 445        adap->bus_recovery_info = NULL;
 446
 447        return -EINVAL;
 448}
 449
 450static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 451{
 452        struct i2c_adapter *adap = client->adapter;
 453        unsigned int irq;
 454
 455        if (!adap->host_notify_domain)
 456                return -ENXIO;
 457
 458        if (client->flags & I2C_CLIENT_TEN)
 459                return -EINVAL;
 460
 461        irq = irq_create_mapping(adap->host_notify_domain, client->addr);
 462
 463        return irq > 0 ? irq : -ENXIO;
 464}
 465
 466static int i2c_device_probe(struct device *dev)
 467{
 468        struct i2c_client       *client = i2c_verify_client(dev);
 469        struct i2c_adapter      *adap;
 470        struct i2c_driver       *driver;
 471        int status;
 472
 473        if (!client)
 474                return 0;
 475
 476        adap = client->adapter;
 477        client->irq = client->init_irq;
 478
 479        if (!client->irq) {
 480                int irq = -ENOENT;
 481
 482                if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 483                        dev_dbg(dev, "Using Host Notify IRQ\n");
 484                        /* Keep adapter active when Host Notify is required */
 485                        pm_runtime_get_sync(&client->adapter->dev);
 486                        irq = i2c_smbus_host_notify_to_irq(client);
 487                } else if (dev->of_node) {
 488                        irq = of_irq_get_byname(dev->of_node, "irq");
 489                        if (irq == -EINVAL || irq == -ENODATA)
 490                                irq = of_irq_get(dev->of_node, 0);
 491                } else if (ACPI_COMPANION(dev)) {
 492                        irq = i2c_acpi_get_irq(client);
 493                }
 494                if (irq == -EPROBE_DEFER) {
 495                        status = irq;
 496                        goto put_sync_adapter;
 497                }
 498
 499                if (irq < 0)
 500                        irq = 0;
 501
 502                client->irq = irq;
 503        }
 504
 505        driver = to_i2c_driver(dev->driver);
 506
 507        /*
 508         * An I2C ID table is not mandatory, if and only if, a suitable OF
 509         * or ACPI ID table is supplied for the probing device.
 510         */
 511        if (!driver->id_table &&
 512            !acpi_driver_match_device(dev, dev->driver) &&
 513            !i2c_of_match_device(dev->driver->of_match_table, client)) {
 514                status = -ENODEV;
 515                goto put_sync_adapter;
 516        }
 517
 518        if (client->flags & I2C_CLIENT_WAKE) {
 519                int wakeirq;
 520
 521                wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 522                if (wakeirq == -EPROBE_DEFER) {
 523                        status = wakeirq;
 524                        goto put_sync_adapter;
 525                }
 526
 527                device_init_wakeup(&client->dev, true);
 528
 529                if (wakeirq > 0 && wakeirq != client->irq)
 530                        status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 531                else if (client->irq > 0)
 532                        status = dev_pm_set_wake_irq(dev, client->irq);
 533                else
 534                        status = 0;
 535
 536                if (status)
 537                        dev_warn(&client->dev, "failed to set up wakeup irq\n");
 538        }
 539
 540        dev_dbg(dev, "probe\n");
 541
 542        if (adap->bus_regulator) {
 543                status = regulator_enable(adap->bus_regulator);
 544                if (status < 0) {
 545                        dev_err(&adap->dev, "Failed to enable bus regulator\n");
 546                        goto err_clear_wakeup_irq;
 547                }
 548        }
 549
 550        status = of_clk_set_defaults(dev->of_node, false);
 551        if (status < 0)
 552                goto err_clear_wakeup_irq;
 553
 554        status = dev_pm_domain_attach(&client->dev, true);
 555        if (status)
 556                goto err_clear_wakeup_irq;
 557
 558        client->devres_group_id = devres_open_group(&client->dev, NULL,
 559                                                    GFP_KERNEL);
 560        if (!client->devres_group_id) {
 561                status = -ENOMEM;
 562                goto err_detach_pm_domain;
 563        }
 564
 565        /*
 566         * When there are no more users of probe(),
 567         * rename probe_new to probe.
 568         */
 569        if (driver->probe_new)
 570                status = driver->probe_new(client);
 571        else if (driver->probe)
 572                status = driver->probe(client,
 573                                       i2c_match_id(driver->id_table, client));
 574        else
 575                status = -EINVAL;
 576
 577        /*
 578         * Note that we are not closing the devres group opened above so
 579         * even resources that were attached to the device after probe is
 580         * run are released when i2c_device_remove() is executed. This is
 581         * needed as some drivers would allocate additional resources,
 582         * for example when updating firmware.
 583         */
 584
 585        if (status)
 586                goto err_release_driver_resources;
 587
 588        return 0;
 589
 590err_release_driver_resources:
 591        devres_release_group(&client->dev, client->devres_group_id);
 592err_detach_pm_domain:
 593        dev_pm_domain_detach(&client->dev, true);
 594err_clear_wakeup_irq:
 595        dev_pm_clear_wake_irq(&client->dev);
 596        device_init_wakeup(&client->dev, false);
 597put_sync_adapter:
 598        if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 599                pm_runtime_put_sync(&client->adapter->dev);
 600
 601        return status;
 602}
 603
 604static int i2c_device_remove(struct device *dev)
 605{
 606        struct i2c_client       *client = to_i2c_client(dev);
 607        struct i2c_adapter      *adap;
 608        struct i2c_driver       *driver;
 609
 610        adap = client->adapter;
 611        driver = to_i2c_driver(dev->driver);
 612        if (driver->remove) {
 613                int status;
 614
 615                dev_dbg(dev, "remove\n");
 616
 617                status = driver->remove(client);
 618                if (status)
 619                        dev_warn(dev, "remove failed (%pe), will be ignored\n", ERR_PTR(status));
 620        }
 621
 622        devres_release_group(&client->dev, client->devres_group_id);
 623
 624        dev_pm_domain_detach(&client->dev, true);
 625        if (!pm_runtime_status_suspended(&client->dev) && adap->bus_regulator)
 626                regulator_disable(adap->bus_regulator);
 627
 628        dev_pm_clear_wake_irq(&client->dev);
 629        device_init_wakeup(&client->dev, false);
 630
 631        client->irq = 0;
 632        if (client->flags & I2C_CLIENT_HOST_NOTIFY)
 633                pm_runtime_put(&client->adapter->dev);
 634
 635        /* return always 0 because there is WIP to make remove-functions void */
 636        return 0;
 637}
 638
 639#ifdef CONFIG_PM_SLEEP
 640static int i2c_resume_early(struct device *dev)
 641{
 642        struct i2c_client *client = i2c_verify_client(dev);
 643        int err;
 644
 645        if (!client)
 646                return 0;
 647
 648        if (pm_runtime_status_suspended(&client->dev) &&
 649                client->adapter->bus_regulator) {
 650                err = regulator_enable(client->adapter->bus_regulator);
 651                if (err)
 652                        return err;
 653        }
 654
 655        return pm_generic_resume_early(&client->dev);
 656}
 657
 658static int i2c_suspend_late(struct device *dev)
 659{
 660        struct i2c_client *client = i2c_verify_client(dev);
 661        int err;
 662
 663        if (!client)
 664                return 0;
 665
 666        err = pm_generic_suspend_late(&client->dev);
 667        if (err)
 668                return err;
 669
 670        if (!pm_runtime_status_suspended(&client->dev) &&
 671                client->adapter->bus_regulator)
 672                return regulator_disable(client->adapter->bus_regulator);
 673
 674        return 0;
 675}
 676#endif
 677
 678#ifdef CONFIG_PM
 679static int i2c_runtime_resume(struct device *dev)
 680{
 681        struct i2c_client *client = i2c_verify_client(dev);
 682        int err;
 683
 684        if (!client)
 685                return 0;
 686
 687        if (client->adapter->bus_regulator) {
 688                err = regulator_enable(client->adapter->bus_regulator);
 689                if (err)
 690                        return err;
 691        }
 692
 693        return pm_generic_runtime_resume(&client->dev);
 694}
 695
 696static int i2c_runtime_suspend(struct device *dev)
 697{
 698        struct i2c_client *client = i2c_verify_client(dev);
 699        int err;
 700
 701        if (!client)
 702                return 0;
 703
 704        err = pm_generic_runtime_suspend(&client->dev);
 705        if (err)
 706                return err;
 707
 708        if (client->adapter->bus_regulator)
 709                return regulator_disable(client->adapter->bus_regulator);
 710        return 0;
 711}
 712#endif
 713
 714static const struct dev_pm_ops i2c_device_pm = {
 715        SET_LATE_SYSTEM_SLEEP_PM_OPS(i2c_suspend_late, i2c_resume_early)
 716        SET_RUNTIME_PM_OPS(i2c_runtime_suspend, i2c_runtime_resume, NULL)
 717};
 718
 719static void i2c_device_shutdown(struct device *dev)
 720{
 721        struct i2c_client *client = i2c_verify_client(dev);
 722        struct i2c_driver *driver;
 723
 724        if (!client || !dev->driver)
 725                return;
 726        driver = to_i2c_driver(dev->driver);
 727        if (driver->shutdown)
 728                driver->shutdown(client);
 729        else if (client->irq > 0)
 730                disable_irq(client->irq);
 731}
 732
 733static void i2c_client_dev_release(struct device *dev)
 734{
 735        kfree(to_i2c_client(dev));
 736}
 737
 738static ssize_t
 739name_show(struct device *dev, struct device_attribute *attr, char *buf)
 740{
 741        return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 742                       to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 743}
 744static DEVICE_ATTR_RO(name);
 745
 746static ssize_t
 747modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
 748{
 749        struct i2c_client *client = to_i2c_client(dev);
 750        int len;
 751
 752        len = of_device_modalias(dev, buf, PAGE_SIZE);
 753        if (len != -ENODEV)
 754                return len;
 755
 756        len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
 757        if (len != -ENODEV)
 758                return len;
 759
 760        return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 761}
 762static DEVICE_ATTR_RO(modalias);
 763
 764static struct attribute *i2c_dev_attrs[] = {
 765        &dev_attr_name.attr,
 766        /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 767        &dev_attr_modalias.attr,
 768        NULL
 769};
 770ATTRIBUTE_GROUPS(i2c_dev);
 771
 772struct bus_type i2c_bus_type = {
 773        .name           = "i2c",
 774        .match          = i2c_device_match,
 775        .probe          = i2c_device_probe,
 776        .remove         = i2c_device_remove,
 777        .shutdown       = i2c_device_shutdown,
 778        .pm             = &i2c_device_pm,
 779};
 780EXPORT_SYMBOL_GPL(i2c_bus_type);
 781
 782struct device_type i2c_client_type = {
 783        .groups         = i2c_dev_groups,
 784        .uevent         = i2c_device_uevent,
 785        .release        = i2c_client_dev_release,
 786};
 787EXPORT_SYMBOL_GPL(i2c_client_type);
 788
 789
 790/**
 791 * i2c_verify_client - return parameter as i2c_client, or NULL
 792 * @dev: device, probably from some driver model iterator
 793 *
 794 * When traversing the driver model tree, perhaps using driver model
 795 * iterators like @device_for_each_child(), you can't assume very much
 796 * about the nodes you find.  Use this function to avoid oopses caused
 797 * by wrongly treating some non-I2C device as an i2c_client.
 798 */
 799struct i2c_client *i2c_verify_client(struct device *dev)
 800{
 801        return (dev->type == &i2c_client_type)
 802                        ? to_i2c_client(dev)
 803                        : NULL;
 804}
 805EXPORT_SYMBOL(i2c_verify_client);
 806
 807
 808/* Return a unique address which takes the flags of the client into account */
 809static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 810{
 811        unsigned short addr = client->addr;
 812
 813        /* For some client flags, add an arbitrary offset to avoid collisions */
 814        if (client->flags & I2C_CLIENT_TEN)
 815                addr |= I2C_ADDR_OFFSET_TEN_BIT;
 816
 817        if (client->flags & I2C_CLIENT_SLAVE)
 818                addr |= I2C_ADDR_OFFSET_SLAVE;
 819
 820        return addr;
 821}
 822
 823/* This is a permissive address validity check, I2C address map constraints
 824 * are purposely not enforced, except for the general call address. */
 825static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
 826{
 827        if (flags & I2C_CLIENT_TEN) {
 828                /* 10-bit address, all values are valid */
 829                if (addr > 0x3ff)
 830                        return -EINVAL;
 831        } else {
 832                /* 7-bit address, reject the general call address */
 833                if (addr == 0x00 || addr > 0x7f)
 834                        return -EINVAL;
 835        }
 836        return 0;
 837}
 838
 839/* And this is a strict address validity check, used when probing. If a
 840 * device uses a reserved address, then it shouldn't be probed. 7-bit
 841 * addressing is assumed, 10-bit address devices are rare and should be
 842 * explicitly enumerated. */
 843int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 844{
 845        /*
 846         * Reserved addresses per I2C specification:
 847         *  0x00       General call address / START byte
 848         *  0x01       CBUS address
 849         *  0x02       Reserved for different bus format
 850         *  0x03       Reserved for future purposes
 851         *  0x04-0x07  Hs-mode master code
 852         *  0x78-0x7b  10-bit slave addressing
 853         *  0x7c-0x7f  Reserved for future purposes
 854         */
 855        if (addr < 0x08 || addr > 0x77)
 856                return -EINVAL;
 857        return 0;
 858}
 859
 860static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 861{
 862        struct i2c_client       *client = i2c_verify_client(dev);
 863        int                     addr = *(int *)addrp;
 864
 865        if (client && i2c_encode_flags_to_addr(client) == addr)
 866                return -EBUSY;
 867        return 0;
 868}
 869
 870/* walk up mux tree */
 871static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 872{
 873        struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 874        int result;
 875
 876        result = device_for_each_child(&adapter->dev, &addr,
 877                                        __i2c_check_addr_busy);
 878
 879        if (!result && parent)
 880                result = i2c_check_mux_parents(parent, addr);
 881
 882        return result;
 883}
 884
 885/* recurse down mux tree */
 886static int i2c_check_mux_children(struct device *dev, void *addrp)
 887{
 888        int result;
 889
 890        if (dev->type == &i2c_adapter_type)
 891                result = device_for_each_child(dev, addrp,
 892                                                i2c_check_mux_children);
 893        else
 894                result = __i2c_check_addr_busy(dev, addrp);
 895
 896        return result;
 897}
 898
 899static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 900{
 901        struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 902        int result = 0;
 903
 904        if (parent)
 905                result = i2c_check_mux_parents(parent, addr);
 906
 907        if (!result)
 908                result = device_for_each_child(&adapter->dev, &addr,
 909                                                i2c_check_mux_children);
 910
 911        return result;
 912}
 913
 914/**
 915 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 916 * @adapter: Target I2C bus segment
 917 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 918 *      locks only this branch in the adapter tree
 919 */
 920static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 921                                 unsigned int flags)
 922{
 923        rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
 924}
 925
 926/**
 927 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 928 * @adapter: Target I2C bus segment
 929 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 930 *      trylocks only this branch in the adapter tree
 931 */
 932static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 933                                   unsigned int flags)
 934{
 935        return rt_mutex_trylock(&adapter->bus_lock);
 936}
 937
 938/**
 939 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 940 * @adapter: Target I2C bus segment
 941 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 942 *      unlocks only this branch in the adapter tree
 943 */
 944static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 945                                   unsigned int flags)
 946{
 947        rt_mutex_unlock(&adapter->bus_lock);
 948}
 949
 950static void i2c_dev_set_name(struct i2c_adapter *adap,
 951                             struct i2c_client *client,
 952                             struct i2c_board_info const *info)
 953{
 954        struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 955
 956        if (info && info->dev_name) {
 957                dev_set_name(&client->dev, "i2c-%s", info->dev_name);
 958                return;
 959        }
 960
 961        if (adev) {
 962                dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 963                return;
 964        }
 965
 966        dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 967                     i2c_encode_flags_to_addr(client));
 968}
 969
 970int i2c_dev_irq_from_resources(const struct resource *resources,
 971                               unsigned int num_resources)
 972{
 973        struct irq_data *irqd;
 974        int i;
 975
 976        for (i = 0; i < num_resources; i++) {
 977                const struct resource *r = &resources[i];
 978
 979                if (resource_type(r) != IORESOURCE_IRQ)
 980                        continue;
 981
 982                if (r->flags & IORESOURCE_BITS) {
 983                        irqd = irq_get_irq_data(r->start);
 984                        if (!irqd)
 985                                break;
 986
 987                        irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 988                }
 989
 990                return r->start;
 991        }
 992
 993        return 0;
 994}
 995
 996/**
 997 * i2c_new_client_device - instantiate an i2c device
 998 * @adap: the adapter managing the device
 999 * @info: describes one I2C device; bus_num is ignored
1000 * Context: can sleep
1001 *
1002 * Create an i2c device. Binding is handled through driver model
1003 * probe()/remove() methods.  A driver may be bound to this device when we
1004 * return from this function, or any later moment (e.g. maybe hotplugging will
1005 * load the driver module).  This call is not appropriate for use by mainboard
1006 * initialization logic, which usually runs during an arch_initcall() long
1007 * before any i2c_adapter could exist.
1008 *
1009 * This returns the new i2c client, which may be saved for later use with
1010 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1011 */
1012struct i2c_client *
1013i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
1014{
1015        struct i2c_client       *client;
1016        int                     status;
1017
1018        client = kzalloc(sizeof *client, GFP_KERNEL);
1019        if (!client)
1020                return ERR_PTR(-ENOMEM);
1021
1022        client->adapter = adap;
1023
1024        client->dev.platform_data = info->platform_data;
1025        client->flags = info->flags;
1026        client->addr = info->addr;
1027
1028        client->init_irq = info->irq;
1029        if (!client->init_irq)
1030                client->init_irq = i2c_dev_irq_from_resources(info->resources,
1031                                                         info->num_resources);
1032
1033        strlcpy(client->name, info->type, sizeof(client->name));
1034
1035        status = i2c_check_addr_validity(client->addr, client->flags);
1036        if (status) {
1037                dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
1038                        client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
1039                goto out_err_silent;
1040        }
1041
1042        /* Check for address business */
1043        status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1044        if (status)
1045                goto out_err;
1046
1047        client->dev.parent = &client->adapter->dev;
1048        client->dev.bus = &i2c_bus_type;
1049        client->dev.type = &i2c_client_type;
1050        client->dev.of_node = of_node_get(info->of_node);
1051        client->dev.fwnode = info->fwnode;
1052
1053        i2c_dev_set_name(adap, client, info);
1054
1055        if (info->swnode) {
1056                status = device_add_software_node(&client->dev, info->swnode);
1057                if (status) {
1058                        dev_err(&adap->dev,
1059                                "Failed to add software node to client %s: %d\n",
1060                                client->name, status);
1061                        goto out_err_put_of_node;
1062                }
1063        }
1064
1065        status = device_register(&client->dev);
1066        if (status)
1067                goto out_remove_swnode;
1068
1069        dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1070                client->name, dev_name(&client->dev));
1071
1072        return client;
1073
1074out_remove_swnode:
1075        device_remove_software_node(&client->dev);
1076out_err_put_of_node:
1077        of_node_put(info->of_node);
1078out_err:
1079        dev_err(&adap->dev,
1080                "Failed to register i2c client %s at 0x%02x (%d)\n",
1081                client->name, client->addr, status);
1082out_err_silent:
1083        kfree(client);
1084        return ERR_PTR(status);
1085}
1086EXPORT_SYMBOL_GPL(i2c_new_client_device);
1087
1088/**
1089 * i2c_unregister_device - reverse effect of i2c_new_*_device()
1090 * @client: value returned from i2c_new_*_device()
1091 * Context: can sleep
1092 */
1093void i2c_unregister_device(struct i2c_client *client)
1094{
1095        if (IS_ERR_OR_NULL(client))
1096                return;
1097
1098        if (client->dev.of_node) {
1099                of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1100                of_node_put(client->dev.of_node);
1101        }
1102
1103        if (ACPI_COMPANION(&client->dev))
1104                acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1105        device_remove_software_node(&client->dev);
1106        device_unregister(&client->dev);
1107}
1108EXPORT_SYMBOL_GPL(i2c_unregister_device);
1109
1110
1111static const struct i2c_device_id dummy_id[] = {
1112        { "dummy", 0 },
1113        { },
1114};
1115
1116static int dummy_probe(struct i2c_client *client,
1117                       const struct i2c_device_id *id)
1118{
1119        return 0;
1120}
1121
1122static int dummy_remove(struct i2c_client *client)
1123{
1124        return 0;
1125}
1126
1127static struct i2c_driver dummy_driver = {
1128        .driver.name    = "dummy",
1129        .probe          = dummy_probe,
1130        .remove         = dummy_remove,
1131        .id_table       = dummy_id,
1132};
1133
1134/**
1135 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1136 * @adapter: the adapter managing the device
1137 * @address: seven bit address to be used
1138 * Context: can sleep
1139 *
1140 * This returns an I2C client bound to the "dummy" driver, intended for use
1141 * with devices that consume multiple addresses.  Examples of such chips
1142 * include various EEPROMS (like 24c04 and 24c08 models).
1143 *
1144 * These dummy devices have two main uses.  First, most I2C and SMBus calls
1145 * except i2c_transfer() need a client handle; the dummy will be that handle.
1146 * And second, this prevents the specified address from being bound to a
1147 * different driver.
1148 *
1149 * This returns the new i2c client, which should be saved for later use with
1150 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1151 */
1152struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1153{
1154        struct i2c_board_info info = {
1155                I2C_BOARD_INFO("dummy", address),
1156        };
1157
1158        return i2c_new_client_device(adapter, &info);
1159}
1160EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1161
1162static void devm_i2c_release_dummy(void *client)
1163{
1164        i2c_unregister_device(client);
1165}
1166
1167/**
1168 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1169 * @dev: device the managed resource is bound to
1170 * @adapter: the adapter managing the device
1171 * @address: seven bit address to be used
1172 * Context: can sleep
1173 *
1174 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1175 * new i2c client or an ERR_PTR in case of an error.
1176 */
1177struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1178                                             struct i2c_adapter *adapter,
1179                                             u16 address)
1180{
1181        struct i2c_client *client;
1182        int ret;
1183
1184        client = i2c_new_dummy_device(adapter, address);
1185        if (IS_ERR(client))
1186                return client;
1187
1188        ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1189        if (ret)
1190                return ERR_PTR(ret);
1191
1192        return client;
1193}
1194EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1195
1196/**
1197 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1198 * and create the associated device
1199 * @client: Handle to the primary client
1200 * @name: Handle to specify which secondary address to get
1201 * @default_addr: Used as a fallback if no secondary address was specified
1202 * Context: can sleep
1203 *
1204 * I2C clients can be composed of multiple I2C slaves bound together in a single
1205 * component. The I2C client driver then binds to the master I2C slave and needs
1206 * to create I2C dummy clients to communicate with all the other slaves.
1207 *
1208 * This function creates and returns an I2C dummy client whose I2C address is
1209 * retrieved from the platform firmware based on the given slave name. If no
1210 * address is specified by the firmware default_addr is used.
1211 *
1212 * On DT-based platforms the address is retrieved from the "reg" property entry
1213 * cell whose "reg-names" value matches the slave name.
1214 *
1215 * This returns the new i2c client, which should be saved for later use with
1216 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1217 */
1218struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1219                                                const char *name,
1220                                                u16 default_addr)
1221{
1222        struct device_node *np = client->dev.of_node;
1223        u32 addr = default_addr;
1224        int i;
1225
1226        if (np) {
1227                i = of_property_match_string(np, "reg-names", name);
1228                if (i >= 0)
1229                        of_property_read_u32_index(np, "reg", i, &addr);
1230        }
1231
1232        dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1233        return i2c_new_dummy_device(client->adapter, addr);
1234}
1235EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1236
1237/* ------------------------------------------------------------------------- */
1238
1239/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1240
1241static void i2c_adapter_dev_release(struct device *dev)
1242{
1243        struct i2c_adapter *adap = to_i2c_adapter(dev);
1244        complete(&adap->dev_released);
1245}
1246
1247unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1248{
1249        unsigned int depth = 0;
1250
1251        while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1252                depth++;
1253
1254        WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1255                  "adapter depth exceeds lockdep subclass limit\n");
1256
1257        return depth;
1258}
1259EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1260
1261/*
1262 * Let users instantiate I2C devices through sysfs. This can be used when
1263 * platform initialization code doesn't contain the proper data for
1264 * whatever reason. Also useful for drivers that do device detection and
1265 * detection fails, either because the device uses an unexpected address,
1266 * or this is a compatible device with different ID register values.
1267 *
1268 * Parameter checking may look overzealous, but we really don't want
1269 * the user to provide incorrect parameters.
1270 */
1271static ssize_t
1272new_device_store(struct device *dev, struct device_attribute *attr,
1273                 const char *buf, size_t count)
1274{
1275        struct i2c_adapter *adap = to_i2c_adapter(dev);
1276        struct i2c_board_info info;
1277        struct i2c_client *client;
1278        char *blank, end;
1279        int res;
1280
1281        memset(&info, 0, sizeof(struct i2c_board_info));
1282
1283        blank = strchr(buf, ' ');
1284        if (!blank) {
1285                dev_err(dev, "%s: Missing parameters\n", "new_device");
1286                return -EINVAL;
1287        }
1288        if (blank - buf > I2C_NAME_SIZE - 1) {
1289                dev_err(dev, "%s: Invalid device name\n", "new_device");
1290                return -EINVAL;
1291        }
1292        memcpy(info.type, buf, blank - buf);
1293
1294        /* Parse remaining parameters, reject extra parameters */
1295        res = sscanf(++blank, "%hi%c", &info.addr, &end);
1296        if (res < 1) {
1297                dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1298                return -EINVAL;
1299        }
1300        if (res > 1  && end != '\n') {
1301                dev_err(dev, "%s: Extra parameters\n", "new_device");
1302                return -EINVAL;
1303        }
1304
1305        if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1306                info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1307                info.flags |= I2C_CLIENT_TEN;
1308        }
1309
1310        if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1311                info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1312                info.flags |= I2C_CLIENT_SLAVE;
1313        }
1314
1315        client = i2c_new_client_device(adap, &info);
1316        if (IS_ERR(client))
1317                return PTR_ERR(client);
1318
1319        /* Keep track of the added device */
1320        mutex_lock(&adap->userspace_clients_lock);
1321        list_add_tail(&client->detected, &adap->userspace_clients);
1322        mutex_unlock(&adap->userspace_clients_lock);
1323        dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1324                 info.type, info.addr);
1325
1326        return count;
1327}
1328static DEVICE_ATTR_WO(new_device);
1329
1330/*
1331 * And of course let the users delete the devices they instantiated, if
1332 * they got it wrong. This interface can only be used to delete devices
1333 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1334 * don't delete devices to which some kernel code still has references.
1335 *
1336 * Parameter checking may look overzealous, but we really don't want
1337 * the user to delete the wrong device.
1338 */
1339static ssize_t
1340delete_device_store(struct device *dev, struct device_attribute *attr,
1341                    const char *buf, size_t count)
1342{
1343        struct i2c_adapter *adap = to_i2c_adapter(dev);
1344        struct i2c_client *client, *next;
1345        unsigned short addr;
1346        char end;
1347        int res;
1348
1349        /* Parse parameters, reject extra parameters */
1350        res = sscanf(buf, "%hi%c", &addr, &end);
1351        if (res < 1) {
1352                dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1353                return -EINVAL;
1354        }
1355        if (res > 1  && end != '\n') {
1356                dev_err(dev, "%s: Extra parameters\n", "delete_device");
1357                return -EINVAL;
1358        }
1359
1360        /* Make sure the device was added through sysfs */
1361        res = -ENOENT;
1362        mutex_lock_nested(&adap->userspace_clients_lock,
1363                          i2c_adapter_depth(adap));
1364        list_for_each_entry_safe(client, next, &adap->userspace_clients,
1365                                 detected) {
1366                if (i2c_encode_flags_to_addr(client) == addr) {
1367                        dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1368                                 "delete_device", client->name, client->addr);
1369
1370                        list_del(&client->detected);
1371                        i2c_unregister_device(client);
1372                        res = count;
1373                        break;
1374                }
1375        }
1376        mutex_unlock(&adap->userspace_clients_lock);
1377
1378        if (res < 0)
1379                dev_err(dev, "%s: Can't find device in list\n",
1380                        "delete_device");
1381        return res;
1382}
1383static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1384                                  delete_device_store);
1385
1386static struct attribute *i2c_adapter_attrs[] = {
1387        &dev_attr_name.attr,
1388        &dev_attr_new_device.attr,
1389        &dev_attr_delete_device.attr,
1390        NULL
1391};
1392ATTRIBUTE_GROUPS(i2c_adapter);
1393
1394struct device_type i2c_adapter_type = {
1395        .groups         = i2c_adapter_groups,
1396        .release        = i2c_adapter_dev_release,
1397};
1398EXPORT_SYMBOL_GPL(i2c_adapter_type);
1399
1400/**
1401 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1402 * @dev: device, probably from some driver model iterator
1403 *
1404 * When traversing the driver model tree, perhaps using driver model
1405 * iterators like @device_for_each_child(), you can't assume very much
1406 * about the nodes you find.  Use this function to avoid oopses caused
1407 * by wrongly treating some non-I2C device as an i2c_adapter.
1408 */
1409struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1410{
1411        return (dev->type == &i2c_adapter_type)
1412                        ? to_i2c_adapter(dev)
1413                        : NULL;
1414}
1415EXPORT_SYMBOL(i2c_verify_adapter);
1416
1417#ifdef CONFIG_I2C_COMPAT
1418static struct class_compat *i2c_adapter_compat_class;
1419#endif
1420
1421static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1422{
1423        struct i2c_devinfo      *devinfo;
1424
1425        down_read(&__i2c_board_lock);
1426        list_for_each_entry(devinfo, &__i2c_board_list, list) {
1427                if (devinfo->busnum == adapter->nr &&
1428                    IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1429                        dev_err(&adapter->dev,
1430                                "Can't create device at 0x%02x\n",
1431                                devinfo->board_info.addr);
1432        }
1433        up_read(&__i2c_board_lock);
1434}
1435
1436static int i2c_do_add_adapter(struct i2c_driver *driver,
1437                              struct i2c_adapter *adap)
1438{
1439        /* Detect supported devices on that bus, and instantiate them */
1440        i2c_detect(adap, driver);
1441
1442        return 0;
1443}
1444
1445static int __process_new_adapter(struct device_driver *d, void *data)
1446{
1447        return i2c_do_add_adapter(to_i2c_driver(d), data);
1448}
1449
1450static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1451        .lock_bus =    i2c_adapter_lock_bus,
1452        .trylock_bus = i2c_adapter_trylock_bus,
1453        .unlock_bus =  i2c_adapter_unlock_bus,
1454};
1455
1456static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1457{
1458        struct irq_domain *domain = adap->host_notify_domain;
1459        irq_hw_number_t hwirq;
1460
1461        if (!domain)
1462                return;
1463
1464        for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1465                irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1466
1467        irq_domain_remove(domain);
1468        adap->host_notify_domain = NULL;
1469}
1470
1471static int i2c_host_notify_irq_map(struct irq_domain *h,
1472                                          unsigned int virq,
1473                                          irq_hw_number_t hw_irq_num)
1474{
1475        irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1476
1477        return 0;
1478}
1479
1480static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1481        .map = i2c_host_notify_irq_map,
1482};
1483
1484static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1485{
1486        struct irq_domain *domain;
1487
1488        if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1489                return 0;
1490
1491        domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1492                                          I2C_ADDR_7BITS_COUNT,
1493                                          &i2c_host_notify_irq_ops, adap);
1494        if (!domain)
1495                return -ENOMEM;
1496
1497        adap->host_notify_domain = domain;
1498
1499        return 0;
1500}
1501
1502/**
1503 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1504 * I2C client.
1505 * @adap: the adapter
1506 * @addr: the I2C address of the notifying device
1507 * Context: can't sleep
1508 *
1509 * Helper function to be called from an I2C bus driver's interrupt
1510 * handler. It will schedule the Host Notify IRQ.
1511 */
1512int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1513{
1514        int irq;
1515
1516        if (!adap)
1517                return -EINVAL;
1518
1519        irq = irq_find_mapping(adap->host_notify_domain, addr);
1520        if (irq <= 0)
1521                return -ENXIO;
1522
1523        generic_handle_irq(irq);
1524
1525        return 0;
1526}
1527EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1528
1529static int i2c_register_adapter(struct i2c_adapter *adap)
1530{
1531        int res = -EINVAL;
1532
1533        /* Can't register until after driver model init */
1534        if (WARN_ON(!is_registered)) {
1535                res = -EAGAIN;
1536                goto out_list;
1537        }
1538
1539        /* Sanity checks */
1540        if (WARN(!adap->name[0], "i2c adapter has no name"))
1541                goto out_list;
1542
1543        if (!adap->algo) {
1544                pr_err("adapter '%s': no algo supplied!\n", adap->name);
1545                goto out_list;
1546        }
1547
1548        if (!adap->lock_ops)
1549                adap->lock_ops = &i2c_adapter_lock_ops;
1550
1551        adap->locked_flags = 0;
1552        rt_mutex_init(&adap->bus_lock);
1553        rt_mutex_init(&adap->mux_lock);
1554        mutex_init(&adap->userspace_clients_lock);
1555        INIT_LIST_HEAD(&adap->userspace_clients);
1556
1557        /* Set default timeout to 1 second if not already set */
1558        if (adap->timeout == 0)
1559                adap->timeout = HZ;
1560
1561        /* register soft irqs for Host Notify */
1562        res = i2c_setup_host_notify_irq_domain(adap);
1563        if (res) {
1564                pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1565                       adap->name, res);
1566                goto out_list;
1567        }
1568
1569        dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1570        adap->dev.bus = &i2c_bus_type;
1571        adap->dev.type = &i2c_adapter_type;
1572        res = device_register(&adap->dev);
1573        if (res) {
1574                pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1575                goto out_list;
1576        }
1577
1578        res = of_i2c_setup_smbus_alert(adap);
1579        if (res)
1580                goto out_reg;
1581
1582        pm_runtime_no_callbacks(&adap->dev);
1583        pm_suspend_ignore_children(&adap->dev, true);
1584        pm_runtime_enable(&adap->dev);
1585
1586        res = i2c_init_recovery(adap);
1587        if (res == -EPROBE_DEFER)
1588                goto out_reg;
1589
1590        dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1591
1592#ifdef CONFIG_I2C_COMPAT
1593        res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1594                                       adap->dev.parent);
1595        if (res)
1596                dev_warn(&adap->dev,
1597                         "Failed to create compatibility class link\n");
1598#endif
1599
1600        /* create pre-declared device nodes */
1601        of_i2c_register_devices(adap);
1602        i2c_acpi_install_space_handler(adap);
1603        i2c_acpi_register_devices(adap);
1604
1605        if (adap->nr < __i2c_first_dynamic_bus_num)
1606                i2c_scan_static_board_info(adap);
1607
1608        /* Notify drivers */
1609        mutex_lock(&core_lock);
1610        bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1611        mutex_unlock(&core_lock);
1612
1613        return 0;
1614
1615out_reg:
1616        init_completion(&adap->dev_released);
1617        device_unregister(&adap->dev);
1618        wait_for_completion(&adap->dev_released);
1619out_list:
1620        mutex_lock(&core_lock);
1621        idr_remove(&i2c_adapter_idr, adap->nr);
1622        mutex_unlock(&core_lock);
1623        return res;
1624}
1625
1626/**
1627 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1628 * @adap: the adapter to register (with adap->nr initialized)
1629 * Context: can sleep
1630 *
1631 * See i2c_add_numbered_adapter() for details.
1632 */
1633static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1634{
1635        int id;
1636
1637        mutex_lock(&core_lock);
1638        id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1639        mutex_unlock(&core_lock);
1640        if (WARN(id < 0, "couldn't get idr"))
1641                return id == -ENOSPC ? -EBUSY : id;
1642
1643        return i2c_register_adapter(adap);
1644}
1645
1646/**
1647 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1648 * @adapter: the adapter to add
1649 * Context: can sleep
1650 *
1651 * This routine is used to declare an I2C adapter when its bus number
1652 * doesn't matter or when its bus number is specified by an dt alias.
1653 * Examples of bases when the bus number doesn't matter: I2C adapters
1654 * dynamically added by USB links or PCI plugin cards.
1655 *
1656 * When this returns zero, a new bus number was allocated and stored
1657 * in adap->nr, and the specified adapter became available for clients.
1658 * Otherwise, a negative errno value is returned.
1659 */
1660int i2c_add_adapter(struct i2c_adapter *adapter)
1661{
1662        struct device *dev = &adapter->dev;
1663        int id;
1664
1665        if (dev->of_node) {
1666                id = of_alias_get_id(dev->of_node, "i2c");
1667                if (id >= 0) {
1668                        adapter->nr = id;
1669                        return __i2c_add_numbered_adapter(adapter);
1670                }
1671        }
1672
1673        mutex_lock(&core_lock);
1674        id = idr_alloc(&i2c_adapter_idr, adapter,
1675                       __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1676        mutex_unlock(&core_lock);
1677        if (WARN(id < 0, "couldn't get idr"))
1678                return id;
1679
1680        adapter->nr = id;
1681
1682        return i2c_register_adapter(adapter);
1683}
1684EXPORT_SYMBOL(i2c_add_adapter);
1685
1686/**
1687 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1688 * @adap: the adapter to register (with adap->nr initialized)
1689 * Context: can sleep
1690 *
1691 * This routine is used to declare an I2C adapter when its bus number
1692 * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1693 * or otherwise built in to the system's mainboard, and where i2c_board_info
1694 * is used to properly configure I2C devices.
1695 *
1696 * If the requested bus number is set to -1, then this function will behave
1697 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1698 *
1699 * If no devices have pre-been declared for this bus, then be sure to
1700 * register the adapter before any dynamically allocated ones.  Otherwise
1701 * the required bus ID may not be available.
1702 *
1703 * When this returns zero, the specified adapter became available for
1704 * clients using the bus number provided in adap->nr.  Also, the table
1705 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1706 * and the appropriate driver model device nodes are created.  Otherwise, a
1707 * negative errno value is returned.
1708 */
1709int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1710{
1711        if (adap->nr == -1) /* -1 means dynamically assign bus id */
1712                return i2c_add_adapter(adap);
1713
1714        return __i2c_add_numbered_adapter(adap);
1715}
1716EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1717
1718static void i2c_do_del_adapter(struct i2c_driver *driver,
1719                              struct i2c_adapter *adapter)
1720{
1721        struct i2c_client *client, *_n;
1722
1723        /* Remove the devices we created ourselves as the result of hardware
1724         * probing (using a driver's detect method) */
1725        list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1726                if (client->adapter == adapter) {
1727                        dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1728                                client->name, client->addr);
1729                        list_del(&client->detected);
1730                        i2c_unregister_device(client);
1731                }
1732        }
1733}
1734
1735static int __unregister_client(struct device *dev, void *dummy)
1736{
1737        struct i2c_client *client = i2c_verify_client(dev);
1738        if (client && strcmp(client->name, "dummy"))
1739                i2c_unregister_device(client);
1740        return 0;
1741}
1742
1743static int __unregister_dummy(struct device *dev, void *dummy)
1744{
1745        struct i2c_client *client = i2c_verify_client(dev);
1746        i2c_unregister_device(client);
1747        return 0;
1748}
1749
1750static int __process_removed_adapter(struct device_driver *d, void *data)
1751{
1752        i2c_do_del_adapter(to_i2c_driver(d), data);
1753        return 0;
1754}
1755
1756/**
1757 * i2c_del_adapter - unregister I2C adapter
1758 * @adap: the adapter being unregistered
1759 * Context: can sleep
1760 *
1761 * This unregisters an I2C adapter which was previously registered
1762 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1763 */
1764void i2c_del_adapter(struct i2c_adapter *adap)
1765{
1766        struct i2c_adapter *found;
1767        struct i2c_client *client, *next;
1768
1769        /* First make sure that this adapter was ever added */
1770        mutex_lock(&core_lock);
1771        found = idr_find(&i2c_adapter_idr, adap->nr);
1772        mutex_unlock(&core_lock);
1773        if (found != adap) {
1774                pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1775                return;
1776        }
1777
1778        i2c_acpi_remove_space_handler(adap);
1779        /* Tell drivers about this removal */
1780        mutex_lock(&core_lock);
1781        bus_for_each_drv(&i2c_bus_type, NULL, adap,
1782                               __process_removed_adapter);
1783        mutex_unlock(&core_lock);
1784
1785        /* Remove devices instantiated from sysfs */
1786        mutex_lock_nested(&adap->userspace_clients_lock,
1787                          i2c_adapter_depth(adap));
1788        list_for_each_entry_safe(client, next, &adap->userspace_clients,
1789                                 detected) {
1790                dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1791                        client->addr);
1792                list_del(&client->detected);
1793                i2c_unregister_device(client);
1794        }
1795        mutex_unlock(&adap->userspace_clients_lock);
1796
1797        /* Detach any active clients. This can't fail, thus we do not
1798         * check the returned value. This is a two-pass process, because
1799         * we can't remove the dummy devices during the first pass: they
1800         * could have been instantiated by real devices wishing to clean
1801         * them up properly, so we give them a chance to do that first. */
1802        device_for_each_child(&adap->dev, NULL, __unregister_client);
1803        device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1804
1805#ifdef CONFIG_I2C_COMPAT
1806        class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1807                                 adap->dev.parent);
1808#endif
1809
1810        /* device name is gone after device_unregister */
1811        dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1812
1813        pm_runtime_disable(&adap->dev);
1814
1815        i2c_host_notify_irq_teardown(adap);
1816
1817        /* wait until all references to the device are gone
1818         *
1819         * FIXME: This is old code and should ideally be replaced by an
1820         * alternative which results in decoupling the lifetime of the struct
1821         * device from the i2c_adapter, like spi or netdev do. Any solution
1822         * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1823         */
1824        init_completion(&adap->dev_released);
1825        device_unregister(&adap->dev);
1826        wait_for_completion(&adap->dev_released);
1827
1828        /* free bus id */
1829        mutex_lock(&core_lock);
1830        idr_remove(&i2c_adapter_idr, adap->nr);
1831        mutex_unlock(&core_lock);
1832
1833        /* Clear the device structure in case this adapter is ever going to be
1834           added again */
1835        memset(&adap->dev, 0, sizeof(adap->dev));
1836}
1837EXPORT_SYMBOL(i2c_del_adapter);
1838
1839static void devm_i2c_del_adapter(void *adapter)
1840{
1841        i2c_del_adapter(adapter);
1842}
1843
1844/**
1845 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1846 * @dev: managing device for adding this I2C adapter
1847 * @adapter: the adapter to add
1848 * Context: can sleep
1849 *
1850 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1851 * but the adapter will be auto deleted on driver detach.
1852 */
1853int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1854{
1855        int ret;
1856
1857        ret = i2c_add_adapter(adapter);
1858        if (ret)
1859                return ret;
1860
1861        return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1862}
1863EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1864
1865static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1866                            u32 def_val, bool use_def)
1867{
1868        int ret;
1869
1870        ret = device_property_read_u32(dev, prop_name, cur_val_p);
1871        if (ret && use_def)
1872                *cur_val_p = def_val;
1873
1874        dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1875}
1876
1877/**
1878 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1879 * @dev: The device to scan for I2C timing properties
1880 * @t: the i2c_timings struct to be filled with values
1881 * @use_defaults: bool to use sane defaults derived from the I2C specification
1882 *                when properties are not found, otherwise don't update
1883 *
1884 * Scan the device for the generic I2C properties describing timing parameters
1885 * for the signal and fill the given struct with the results. If a property was
1886 * not found and use_defaults was true, then maximum timings are assumed which
1887 * are derived from the I2C specification. If use_defaults is not used, the
1888 * results will be as before, so drivers can apply their own defaults before
1889 * calling this helper. The latter is mainly intended for avoiding regressions
1890 * of existing drivers which want to switch to this function. New drivers
1891 * almost always should use the defaults.
1892 */
1893void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1894{
1895        bool u = use_defaults;
1896        u32 d;
1897
1898        i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1899                         I2C_MAX_STANDARD_MODE_FREQ, u);
1900
1901        d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1902            t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1903        i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1904
1905        d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1906        i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1907
1908        i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1909                         &t->scl_int_delay_ns, 0, u);
1910        i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1911                         t->scl_fall_ns, u);
1912        i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1913        i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1914                         &t->digital_filter_width_ns, 0, u);
1915        i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1916                         &t->analog_filter_cutoff_freq_hz, 0, u);
1917}
1918EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1919
1920/* ------------------------------------------------------------------------- */
1921
1922int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1923{
1924        int res;
1925
1926        mutex_lock(&core_lock);
1927        res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1928        mutex_unlock(&core_lock);
1929
1930        return res;
1931}
1932EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1933
1934static int __process_new_driver(struct device *dev, void *data)
1935{
1936        if (dev->type != &i2c_adapter_type)
1937                return 0;
1938        return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1939}
1940
1941/*
1942 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1943 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1944 */
1945
1946int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1947{
1948        int res;
1949
1950        /* Can't register until after driver model init */
1951        if (WARN_ON(!is_registered))
1952                return -EAGAIN;
1953
1954        /* add the driver to the list of i2c drivers in the driver core */
1955        driver->driver.owner = owner;
1956        driver->driver.bus = &i2c_bus_type;
1957        INIT_LIST_HEAD(&driver->clients);
1958
1959        /* When registration returns, the driver core
1960         * will have called probe() for all matching-but-unbound devices.
1961         */
1962        res = driver_register(&driver->driver);
1963        if (res)
1964                return res;
1965
1966        pr_debug("driver [%s] registered\n", driver->driver.name);
1967
1968        /* Walk the adapters that are already present */
1969        i2c_for_each_dev(driver, __process_new_driver);
1970
1971        return 0;
1972}
1973EXPORT_SYMBOL(i2c_register_driver);
1974
1975static int __process_removed_driver(struct device *dev, void *data)
1976{
1977        if (dev->type == &i2c_adapter_type)
1978                i2c_do_del_adapter(data, to_i2c_adapter(dev));
1979        return 0;
1980}
1981
1982/**
1983 * i2c_del_driver - unregister I2C driver
1984 * @driver: the driver being unregistered
1985 * Context: can sleep
1986 */
1987void i2c_del_driver(struct i2c_driver *driver)
1988{
1989        i2c_for_each_dev(driver, __process_removed_driver);
1990
1991        driver_unregister(&driver->driver);
1992        pr_debug("driver [%s] unregistered\n", driver->driver.name);
1993}
1994EXPORT_SYMBOL(i2c_del_driver);
1995
1996/* ------------------------------------------------------------------------- */
1997
1998struct i2c_cmd_arg {
1999        unsigned        cmd;
2000        void            *arg;
2001};
2002
2003static int i2c_cmd(struct device *dev, void *_arg)
2004{
2005        struct i2c_client       *client = i2c_verify_client(dev);
2006        struct i2c_cmd_arg      *arg = _arg;
2007        struct i2c_driver       *driver;
2008
2009        if (!client || !client->dev.driver)
2010                return 0;
2011
2012        driver = to_i2c_driver(client->dev.driver);
2013        if (driver->command)
2014                driver->command(client, arg->cmd, arg->arg);
2015        return 0;
2016}
2017
2018void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2019{
2020        struct i2c_cmd_arg      cmd_arg;
2021
2022        cmd_arg.cmd = cmd;
2023        cmd_arg.arg = arg;
2024        device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2025}
2026EXPORT_SYMBOL(i2c_clients_command);
2027
2028static int __init i2c_init(void)
2029{
2030        int retval;
2031
2032        retval = of_alias_get_highest_id("i2c");
2033
2034        down_write(&__i2c_board_lock);
2035        if (retval >= __i2c_first_dynamic_bus_num)
2036                __i2c_first_dynamic_bus_num = retval + 1;
2037        up_write(&__i2c_board_lock);
2038
2039        retval = bus_register(&i2c_bus_type);
2040        if (retval)
2041                return retval;
2042
2043        is_registered = true;
2044
2045#ifdef CONFIG_I2C_COMPAT
2046        i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2047        if (!i2c_adapter_compat_class) {
2048                retval = -ENOMEM;
2049                goto bus_err;
2050        }
2051#endif
2052        retval = i2c_add_driver(&dummy_driver);
2053        if (retval)
2054                goto class_err;
2055
2056        if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2057                WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2058        if (IS_ENABLED(CONFIG_ACPI))
2059                WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2060
2061        return 0;
2062
2063class_err:
2064#ifdef CONFIG_I2C_COMPAT
2065        class_compat_unregister(i2c_adapter_compat_class);
2066bus_err:
2067#endif
2068        is_registered = false;
2069        bus_unregister(&i2c_bus_type);
2070        return retval;
2071}
2072
2073static void __exit i2c_exit(void)
2074{
2075        if (IS_ENABLED(CONFIG_ACPI))
2076                WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2077        if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2078                WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2079        i2c_del_driver(&dummy_driver);
2080#ifdef CONFIG_I2C_COMPAT
2081        class_compat_unregister(i2c_adapter_compat_class);
2082#endif
2083        bus_unregister(&i2c_bus_type);
2084        tracepoint_synchronize_unregister();
2085}
2086
2087/* We must initialize early, because some subsystems register i2c drivers
2088 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2089 */
2090postcore_initcall(i2c_init);
2091module_exit(i2c_exit);
2092
2093/* ----------------------------------------------------
2094 * the functional interface to the i2c busses.
2095 * ----------------------------------------------------
2096 */
2097
2098/* Check if val is exceeding the quirk IFF quirk is non 0 */
2099#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2100
2101static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2102{
2103        dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2104                            err_msg, msg->addr, msg->len,
2105                            msg->flags & I2C_M_RD ? "read" : "write");
2106        return -EOPNOTSUPP;
2107}
2108
2109static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2110{
2111        const struct i2c_adapter_quirks *q = adap->quirks;
2112        int max_num = q->max_num_msgs, i;
2113        bool do_len_check = true;
2114
2115        if (q->flags & I2C_AQ_COMB) {
2116                max_num = 2;
2117
2118                /* special checks for combined messages */
2119                if (num == 2) {
2120                        if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2121                                return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2122
2123                        if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2124                                return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2125
2126                        if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2127                                return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2128
2129                        if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2130                                return i2c_quirk_error(adap, &msgs[0], "msg too long");
2131
2132                        if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2133                                return i2c_quirk_error(adap, &msgs[1], "msg too long");
2134
2135                        do_len_check = false;
2136                }
2137        }
2138
2139        if (i2c_quirk_exceeded(num, max_num))
2140                return i2c_quirk_error(adap, &msgs[0], "too many messages");
2141
2142        for (i = 0; i < num; i++) {
2143                u16 len = msgs[i].len;
2144
2145                if (msgs[i].flags & I2C_M_RD) {
2146                        if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2147                                return i2c_quirk_error(adap, &msgs[i], "msg too long");
2148
2149                        if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2150                                return i2c_quirk_error(adap, &msgs[i], "no zero length");
2151                } else {
2152                        if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2153                                return i2c_quirk_error(adap, &msgs[i], "msg too long");
2154
2155                        if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2156                                return i2c_quirk_error(adap, &msgs[i], "no zero length");
2157                }
2158        }
2159
2160        return 0;
2161}
2162
2163/**
2164 * __i2c_transfer - unlocked flavor of i2c_transfer
2165 * @adap: Handle to I2C bus
2166 * @msgs: One or more messages to execute before STOP is issued to
2167 *      terminate the operation; each message begins with a START.
2168 * @num: Number of messages to be executed.
2169 *
2170 * Returns negative errno, else the number of messages executed.
2171 *
2172 * Adapter lock must be held when calling this function. No debug logging
2173 * takes place. adap->algo->master_xfer existence isn't checked.
2174 */
2175int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2176{
2177        unsigned long orig_jiffies;
2178        int ret, try;
2179
2180        if (WARN_ON(!msgs || num < 1))
2181                return -EINVAL;
2182
2183        ret = __i2c_check_suspended(adap);
2184        if (ret)
2185                return ret;
2186
2187        if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2188                return -EOPNOTSUPP;
2189
2190        /*
2191         * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2192         * enabled.  This is an efficient way of keeping the for-loop from
2193         * being executed when not needed.
2194         */
2195        if (static_branch_unlikely(&i2c_trace_msg_key)) {
2196                int i;
2197                for (i = 0; i < num; i++)
2198                        if (msgs[i].flags & I2C_M_RD)
2199                                trace_i2c_read(adap, &msgs[i], i);
2200                        else
2201                                trace_i2c_write(adap, &msgs[i], i);
2202        }
2203
2204        /* Retry automatically on arbitration loss */
2205        orig_jiffies = jiffies;
2206        for (ret = 0, try = 0; try <= adap->retries; try++) {
2207                if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2208                        ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2209                else
2210                        ret = adap->algo->master_xfer(adap, msgs, num);
2211
2212                if (ret != -EAGAIN)
2213                        break;
2214                if (time_after(jiffies, orig_jiffies + adap->timeout))
2215                        break;
2216        }
2217
2218        if (static_branch_unlikely(&i2c_trace_msg_key)) {
2219                int i;
2220                for (i = 0; i < ret; i++)
2221                        if (msgs[i].flags & I2C_M_RD)
2222                                trace_i2c_reply(adap, &msgs[i], i);
2223                trace_i2c_result(adap, num, ret);
2224        }
2225
2226        return ret;
2227}
2228EXPORT_SYMBOL(__i2c_transfer);
2229
2230/**
2231 * i2c_transfer - execute a single or combined I2C message
2232 * @adap: Handle to I2C bus
2233 * @msgs: One or more messages to execute before STOP is issued to
2234 *      terminate the operation; each message begins with a START.
2235 * @num: Number of messages to be executed.
2236 *
2237 * Returns negative errno, else the number of messages executed.
2238 *
2239 * Note that there is no requirement that each message be sent to
2240 * the same slave address, although that is the most common model.
2241 */
2242int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2243{
2244        int ret;
2245
2246        if (!adap->algo->master_xfer) {
2247                dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2248                return -EOPNOTSUPP;
2249        }
2250
2251        /* REVISIT the fault reporting model here is weak:
2252         *
2253         *  - When we get an error after receiving N bytes from a slave,
2254         *    there is no way to report "N".
2255         *
2256         *  - When we get a NAK after transmitting N bytes to a slave,
2257         *    there is no way to report "N" ... or to let the master
2258         *    continue executing the rest of this combined message, if
2259         *    that's the appropriate response.
2260         *
2261         *  - When for example "num" is two and we successfully complete
2262         *    the first message but get an error part way through the
2263         *    second, it's unclear whether that should be reported as
2264         *    one (discarding status on the second message) or errno
2265         *    (discarding status on the first one).
2266         */
2267        ret = __i2c_lock_bus_helper(adap);
2268        if (ret)
2269                return ret;
2270
2271        ret = __i2c_transfer(adap, msgs, num);
2272        i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2273
2274        return ret;
2275}
2276EXPORT_SYMBOL(i2c_transfer);
2277
2278/**
2279 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2280 *                             to/from a buffer
2281 * @client: Handle to slave device
2282 * @buf: Where the data is stored
2283 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2284 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2285 *
2286 * Returns negative errno, or else the number of bytes transferred.
2287 */
2288int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2289                              int count, u16 flags)
2290{
2291        int ret;
2292        struct i2c_msg msg = {
2293                .addr = client->addr,
2294                .flags = flags | (client->flags & I2C_M_TEN),
2295                .len = count,
2296                .buf = buf,
2297        };
2298
2299        ret = i2c_transfer(client->adapter, &msg, 1);
2300
2301        /*
2302         * If everything went ok (i.e. 1 msg transferred), return #bytes
2303         * transferred, else error code.
2304         */
2305        return (ret == 1) ? count : ret;
2306}
2307EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2308
2309/**
2310 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2311 * @client: The device to query
2312 * @id: The queried information
2313 *
2314 * Returns negative errno on error, zero on success.
2315 */
2316int i2c_get_device_id(const struct i2c_client *client,
2317                      struct i2c_device_identity *id)
2318{
2319        struct i2c_adapter *adap = client->adapter;
2320        union i2c_smbus_data raw_id;
2321        int ret;
2322
2323        if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2324                return -EOPNOTSUPP;
2325
2326        raw_id.block[0] = 3;
2327        ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2328                             I2C_SMBUS_READ, client->addr << 1,
2329                             I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2330        if (ret)
2331                return ret;
2332
2333        id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2334        id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2335        id->die_revision = raw_id.block[3] & 0x7;
2336        return 0;
2337}
2338EXPORT_SYMBOL_GPL(i2c_get_device_id);
2339
2340/* ----------------------------------------------------
2341 * the i2c address scanning function
2342 * Will not work for 10-bit addresses!
2343 * ----------------------------------------------------
2344 */
2345
2346/*
2347 * Legacy default probe function, mostly relevant for SMBus. The default
2348 * probe method is a quick write, but it is known to corrupt the 24RF08
2349 * EEPROMs due to a state machine bug, and could also irreversibly
2350 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2351 * we use a short byte read instead. Also, some bus drivers don't implement
2352 * quick write, so we fallback to a byte read in that case too.
2353 * On x86, there is another special case for FSC hardware monitoring chips,
2354 * which want regular byte reads (address 0x73.) Fortunately, these are the
2355 * only known chips using this I2C address on PC hardware.
2356 * Returns 1 if probe succeeded, 0 if not.
2357 */
2358static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2359{
2360        int err;
2361        union i2c_smbus_data dummy;
2362
2363#ifdef CONFIG_X86
2364        if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2365         && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2366                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2367                                     I2C_SMBUS_BYTE_DATA, &dummy);
2368        else
2369#endif
2370        if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2371         && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2372                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2373                                     I2C_SMBUS_QUICK, NULL);
2374        else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2375                err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2376                                     I2C_SMBUS_BYTE, &dummy);
2377        else {
2378                dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2379                         addr);
2380                err = -EOPNOTSUPP;
2381        }
2382
2383        return err >= 0;
2384}
2385
2386static int i2c_detect_address(struct i2c_client *temp_client,
2387                              struct i2c_driver *driver)
2388{
2389        struct i2c_board_info info;
2390        struct i2c_adapter *adapter = temp_client->adapter;
2391        int addr = temp_client->addr;
2392        int err;
2393
2394        /* Make sure the address is valid */
2395        err = i2c_check_7bit_addr_validity_strict(addr);
2396        if (err) {
2397                dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2398                         addr);
2399                return err;
2400        }
2401
2402        /* Skip if already in use (7 bit, no need to encode flags) */
2403        if (i2c_check_addr_busy(adapter, addr))
2404                return 0;
2405
2406        /* Make sure there is something at this address */
2407        if (!i2c_default_probe(adapter, addr))
2408                return 0;
2409
2410        /* Finally call the custom detection function */
2411        memset(&info, 0, sizeof(struct i2c_board_info));
2412        info.addr = addr;
2413        err = driver->detect(temp_client, &info);
2414        if (err) {
2415                /* -ENODEV is returned if the detection fails. We catch it
2416                   here as this isn't an error. */
2417                return err == -ENODEV ? 0 : err;
2418        }
2419
2420        /* Consistency check */
2421        if (info.type[0] == '\0') {
2422                dev_err(&adapter->dev,
2423                        "%s detection function provided no name for 0x%x\n",
2424                        driver->driver.name, addr);
2425        } else {
2426                struct i2c_client *client;
2427
2428                /* Detection succeeded, instantiate the device */
2429                if (adapter->class & I2C_CLASS_DEPRECATED)
2430                        dev_warn(&adapter->dev,
2431                                "This adapter will soon drop class based instantiation of devices. "
2432                                "Please make sure client 0x%02x gets instantiated by other means. "
2433                                "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2434                                info.addr);
2435
2436                dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2437                        info.type, info.addr);
2438                client = i2c_new_client_device(adapter, &info);
2439                if (!IS_ERR(client))
2440                        list_add_tail(&client->detected, &driver->clients);
2441                else
2442                        dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2443                                info.type, info.addr);
2444        }
2445        return 0;
2446}
2447
2448static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2449{
2450        const unsigned short *address_list;
2451        struct i2c_client *temp_client;
2452        int i, err = 0;
2453
2454        address_list = driver->address_list;
2455        if (!driver->detect || !address_list)
2456                return 0;
2457
2458        /* Warn that the adapter lost class based instantiation */
2459        if (adapter->class == I2C_CLASS_DEPRECATED) {
2460                dev_dbg(&adapter->dev,
2461                        "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2462                        "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2463                        driver->driver.name);
2464                return 0;
2465        }
2466
2467        /* Stop here if the classes do not match */
2468        if (!(adapter->class & driver->class))
2469                return 0;
2470
2471        /* Set up a temporary client to help detect callback */
2472        temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2473        if (!temp_client)
2474                return -ENOMEM;
2475        temp_client->adapter = adapter;
2476
2477        for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2478                dev_dbg(&adapter->dev,
2479                        "found normal entry for adapter %d, addr 0x%02x\n",
2480                        i2c_adapter_id(adapter), address_list[i]);
2481                temp_client->addr = address_list[i];
2482                err = i2c_detect_address(temp_client, driver);
2483                if (unlikely(err))
2484                        break;
2485        }
2486
2487        kfree(temp_client);
2488        return err;
2489}
2490
2491int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2492{
2493        return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2494                              I2C_SMBUS_QUICK, NULL) >= 0;
2495}
2496EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2497
2498struct i2c_client *
2499i2c_new_scanned_device(struct i2c_adapter *adap,
2500                       struct i2c_board_info *info,
2501                       unsigned short const *addr_list,
2502                       int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2503{
2504        int i;
2505
2506        if (!probe)
2507                probe = i2c_default_probe;
2508
2509        for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2510                /* Check address validity */
2511                if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2512                        dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2513                                 addr_list[i]);
2514                        continue;
2515                }
2516
2517                /* Check address availability (7 bit, no need to encode flags) */
2518                if (i2c_check_addr_busy(adap, addr_list[i])) {
2519                        dev_dbg(&adap->dev,
2520                                "Address 0x%02x already in use, not probing\n",
2521                                addr_list[i]);
2522                        continue;
2523                }
2524
2525                /* Test address responsiveness */
2526                if (probe(adap, addr_list[i]))
2527                        break;
2528        }
2529
2530        if (addr_list[i] == I2C_CLIENT_END) {
2531                dev_dbg(&adap->dev, "Probing failed, no device found\n");
2532                return ERR_PTR(-ENODEV);
2533        }
2534
2535        info->addr = addr_list[i];
2536        return i2c_new_client_device(adap, info);
2537}
2538EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2539
2540struct i2c_adapter *i2c_get_adapter(int nr)
2541{
2542        struct i2c_adapter *adapter;
2543
2544        mutex_lock(&core_lock);
2545        adapter = idr_find(&i2c_adapter_idr, nr);
2546        if (!adapter)
2547                goto exit;
2548
2549        if (try_module_get(adapter->owner))
2550                get_device(&adapter->dev);
2551        else
2552                adapter = NULL;
2553
2554 exit:
2555        mutex_unlock(&core_lock);
2556        return adapter;
2557}
2558EXPORT_SYMBOL(i2c_get_adapter);
2559
2560void i2c_put_adapter(struct i2c_adapter *adap)
2561{
2562        if (!adap)
2563                return;
2564
2565        put_device(&adap->dev);
2566        module_put(adap->owner);
2567}
2568EXPORT_SYMBOL(i2c_put_adapter);
2569
2570/**
2571 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2572 * @msg: the message to be checked
2573 * @threshold: the minimum number of bytes for which using DMA makes sense.
2574 *             Should at least be 1.
2575 *
2576 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2577 *         Or a valid pointer to be used with DMA. After use, release it by
2578 *         calling i2c_put_dma_safe_msg_buf().
2579 *
2580 * This function must only be called from process context!
2581 */
2582u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2583{
2584        /* also skip 0-length msgs for bogus thresholds of 0 */
2585        if (!threshold)
2586                pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2587                         msg->addr);
2588        if (msg->len < threshold || msg->len == 0)
2589                return NULL;
2590
2591        if (msg->flags & I2C_M_DMA_SAFE)
2592                return msg->buf;
2593
2594        pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2595                 msg->addr, msg->len);
2596
2597        if (msg->flags & I2C_M_RD)
2598                return kzalloc(msg->len, GFP_KERNEL);
2599        else
2600                return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2601}
2602EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2603
2604/**
2605 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2606 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2607 * @msg: the message which the buffer corresponds to
2608 * @xferred: bool saying if the message was transferred
2609 */
2610void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2611{
2612        if (!buf || buf == msg->buf)
2613                return;
2614
2615        if (xferred && msg->flags & I2C_M_RD)
2616                memcpy(msg->buf, buf, msg->len);
2617
2618        kfree(buf);
2619}
2620EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2621
2622MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2623MODULE_DESCRIPTION("I2C-Bus main module");
2624MODULE_LICENSE("GPL");
2625