drivers/i2c/i2c-core-acpi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Linux I2C core ACPI support code
   4  *
   5  * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <[email protected]>
   6  */
   7
   8 #include <linux/acpi.h>
   9 #include <linux/device.h>
  10 #include <linux/err.h>
  11 #include <linux/i2c.h>
  12 #include <linux/list.h>
  13 #include <linux/module.h>
  14 #include <linux/slab.h>
  15
  16 #include "i2c-core.h"
  17
  18 struct i2c_acpi_handler_data {
  19         struct acpi_connection_info info;
  20         struct i2c_adapter *adapter;
  21 };
  22
  23 struct gsb_buffer {
  24         u8      status;
  25         u8      len;
  26         union {
  27                 u16     wdata;
  28                 u8      bdata;
  29                 u8      data[0];
  30         };
  31 } __packed;
  32
  33 struct i2c_acpi_lookup {
  34         struct i2c_board_info *info;
  35         acpi_handle adapter_handle;
  36         acpi_handle device_handle;
  37         acpi_handle search_handle;
  38         int n;
  39         int index;
  40         u32 speed;
  41         u32 min_speed;
  42 };
  43
  44 /**
  45  * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches
  46  * @ares:       ACPI resource
  47  * @i2c:        Pointer to I2cSerialBus resource will be returned here
  48  *
  49  * Checks if the given ACPI resource is of type I2cSerialBus.
  50  * In this case, returns a pointer to it to the caller.
  51  *
  52  * Returns true if resource type is of I2cSerialBus, otherwise false.
  53  */
  54 bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares,
  55                                struct acpi_resource_i2c_serialbus **i2c)
  56 {
  57         struct acpi_resource_i2c_serialbus *sb;
  58
  59         if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
  60                 return false;
  61
  62         sb = &ares->data.i2c_serial_bus;
  63         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
  64                 return false;
  65
  66         *i2c = sb;
  67         return true;
  68 }
  69 EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource);
  70
  71 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
  72 {
  73         struct i2c_acpi_lookup *lookup = data;
  74         struct i2c_board_info *info = lookup->info;
  75         struct acpi_resource_i2c_serialbus *sb;
  76         acpi_status status;
  77
  78         if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb))
  79                 return 1;
  80
  81         if (lookup->index != -1 && lookup->n++ != lookup->index)
  82                 return 1;
  83
  84         status = acpi_get_handle(lookup->device_handle,
  85                                  sb->resource_source.string_ptr,
  86                                  &lookup->adapter_handle);
  87         if (ACPI_FAILURE(status))
  88                 return 1;
  89
  90         info->addr = sb->slave_address;
  91         lookup->speed = sb->connection_speed;
  92         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
  93                 info->flags |= I2C_CLIENT_TEN;
  94
  95         return 1;
  96 }
  97
  98 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
  99         /*
 100          * ACPI video acpi_devices, which are handled by the acpi-video driver
 101          * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
 102          */
 103         { ACPI_VIDEO_HID, 0 },
 104         {}
 105 };
 106
 107 static int i2c_acpi_do_lookup(struct acpi_device *adev,
 108                               struct i2c_acpi_lookup *lookup)
 109 {
 110         struct i2c_board_info *info = lookup->info;
 111         struct list_head resource_list;
 112         int ret;
 113
 114         if (acpi_bus_get_status(adev) || !adev->status.present)
 115                 return -EINVAL;
 116
 117         if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
 118                 return -ENODEV;
 119
 120         memset(info, 0, sizeof(*info));
 121         lookup->device_handle = acpi_device_handle(adev);
 122
 123         /* Look up for I2cSerialBus resource */
 124         INIT_LIST_HEAD(&resource_list);
 125         ret = acpi_dev_get_resources(adev, &resource_list,
 126                                      i2c_acpi_fill_info, lookup);
 127         acpi_dev_free_resource_list(&resource_list);
 128
 129         if (ret < 0 || !info->addr)
 130                 return -EINVAL;
 131
 132         return 0;
 133 }
 134
 135 static int i2c_acpi_get_info(struct acpi_device *adev,
 136                              struct i2c_board_info *info,
 137                              struct i2c_adapter *adapter,
 138                              acpi_handle *adapter_handle)
 139 {
 140         struct list_head resource_list;
 141         struct resource_entry *entry;
 142         struct i2c_acpi_lookup lookup;
 143         int ret;
 144
 145         memset(&lookup, 0, sizeof(lookup));
 146         lookup.info = info;
 147         lookup.index = -1;
 148
 149         if (acpi_device_enumerated(adev))
 150                 return -EINVAL;
 151
 152         ret = i2c_acpi_do_lookup(adev, &lookup);
 153         if (ret)
 154                 return ret;
 155
 156         if (adapter) {
 157                 /* The adapter must match the one in I2cSerialBus() connector */
 158                 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
 159                         return -ENODEV;
 160         } else {
 161                 struct acpi_device *adapter_adev;
 162
 163                 /* The adapter must be present */
 164                 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
 165                         return -ENODEV;
 166                 if (acpi_bus_get_status(adapter_adev) ||
 167                     !adapter_adev->status.present)
 168                         return -ENODEV;
 169         }
 170
 171         info->fwnode = acpi_fwnode_handle(adev);
 172         if (adapter_handle)
 173                 *adapter_handle = lookup.adapter_handle;
 174
 175         /* Then fill IRQ number if any */
 176         INIT_LIST_HEAD(&resource_list);
 177         ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
 178         if (ret < 0)
 179                 return -EINVAL;
 180
 181         resource_list_for_each_entry(entry, &resource_list) {
 182                 if (resource_type(entry->res) == IORESOURCE_IRQ) {
 183                         info->irq = entry->res->start;
 184                         break;
 185                 }
 186         }
 187
 188         acpi_dev_free_resource_list(&resource_list);
 189
 190         acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
 191                           sizeof(info->type));
 192
 193         return 0;
 194 }
 195
 196 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
 197                                      struct acpi_device *adev,
 198                                      struct i2c_board_info *info)
 199 {
 200         adev->power.flags.ignore_parent = true;
 201         acpi_device_set_enumerated(adev);
 202
 203         if (!i2c_new_device(adapter, info)) {
 204                 adev->power.flags.ignore_parent = false;
 205                 dev_err(&adapter->dev,
 206                         "failed to add I2C device %s from ACPI\n",
 207                         dev_name(&adev->dev));
 208         }
 209 }
 210
 211 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
 212                                        void *data, void **return_value)
 213 {
 214         struct i2c_adapter *adapter = data;
 215         struct acpi_device *adev;
 216         struct i2c_board_info info;
 217
 218         if (acpi_bus_get_device(handle, &adev))
 219                 return AE_OK;
 220
 221         if (i2c_acpi_get_info(adev, &info, adapter, NULL))
 222                 return AE_OK;
 223
 224         i2c_acpi_register_device(adapter, adev, &info);
 225
 226         return AE_OK;
 227 }
 228
 229 #define I2C_ACPI_MAX_SCAN_DEPTH 32
 230
 231 /**
 232  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
 233  * @adap: pointer to adapter
 234  *
 235  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 236  * namespace. When a device is found it will be added to the Linux device
 237  * model and bound to the corresponding ACPI handle.
 238  */
 239 void i2c_acpi_register_devices(struct i2c_adapter *adap)
 240 {
 241         acpi_status status;
 242
 243         if (!has_acpi_companion(&adap->dev))
 244                 return;
 245
 246         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 247                                      I2C_ACPI_MAX_SCAN_DEPTH,
 248                                      i2c_acpi_add_device, NULL,
 249                                      adap, NULL);
 250         if (ACPI_FAILURE(status))
 251                 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 252 }
 253
 254 const struct acpi_device_id *
 255 i2c_acpi_match_device(const struct acpi_device_id *matches,
 256                       struct i2c_client *client)
 257 {
 258         if (!(client && matches))
 259                 return NULL;
 260
 261         return acpi_match_device(matches, &client->dev);
 262 }
 263
 264 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
 265                                            void *data, void **return_value)
 266 {
 267         struct i2c_acpi_lookup *lookup = data;
 268         struct acpi_device *adev;
 269
 270         if (acpi_bus_get_device(handle, &adev))
 271                 return AE_OK;
 272
 273         if (i2c_acpi_do_lookup(adev, lookup))
 274                 return AE_OK;
 275
 276         if (lookup->search_handle != lookup->adapter_handle)
 277                 return AE_OK;
 278
 279         if (lookup->speed <= lookup->min_speed)
 280                 lookup->min_speed = lookup->speed;
 281
 282         return AE_OK;
 283 }
 284
 285 /**
 286  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
 287  * @dev: The device owning the bus
 288  *
 289  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
 290  * devices connected to this bus and use the speed of slowest device.
 291  *
 292  * Returns the speed in Hz or zero
 293  */
 294 u32 i2c_acpi_find_bus_speed(struct device *dev)
 295 {
 296         struct i2c_acpi_lookup lookup;
 297         struct i2c_board_info dummy;
 298         acpi_status status;
 299
 300         if (!has_acpi_companion(dev))
 301                 return 0;
 302
 303         memset(&lookup, 0, sizeof(lookup));
 304         lookup.search_handle = ACPI_HANDLE(dev);
 305         lookup.min_speed = UINT_MAX;
 306         lookup.info = &dummy;
 307         lookup.index = -1;
 308
 309         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 310                                      I2C_ACPI_MAX_SCAN_DEPTH,
 311                                      i2c_acpi_lookup_speed, NULL,
 312                                      &lookup, NULL);
 313
 314         if (ACPI_FAILURE(status)) {
 315                 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
 316                 return 0;
 317         }
 318
 319         return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
 320 }
 321 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
 322
 323 static int i2c_acpi_find_match_adapter(struct device *dev, void *data)
 324 {
 325         struct i2c_adapter *adapter = i2c_verify_adapter(dev);
 326
 327         if (!adapter)
 328                 return 0;
 329
 330         return ACPI_HANDLE(dev) == (acpi_handle)data;
 331 }
 332
 333 static int i2c_acpi_find_match_device(struct device *dev, void *data)
 334 {
 335         return ACPI_COMPANION(dev) == data;
 336 }
 337
 338 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
 339 {
 340         struct device *dev;
 341
 342         dev = bus_find_device(&i2c_bus_type, NULL, handle,
 343                               i2c_acpi_find_match_adapter);
 344         return dev ? i2c_verify_adapter(dev) : NULL;
 345 }
 346 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle);
 347
 348 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
 349 {
 350         struct device *dev;
 351
 352         dev = bus_find_device(&i2c_bus_type, NULL, adev,
 353                               i2c_acpi_find_match_device);
 354         return dev ? i2c_verify_client(dev) : NULL;
 355 }
 356
 357 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
 358                            void *arg)
 359 {
 360         struct acpi_device *adev = arg;
 361         struct i2c_board_info info;
 362         acpi_handle adapter_handle;
 363         struct i2c_adapter *adapter;
 364         struct i2c_client *client;
 365
 366         switch (value) {
 367         case ACPI_RECONFIG_DEVICE_ADD:
 368                 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
 369                         break;
 370
 371                 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
 372                 if (!adapter)
 373                         break;
 374
 375                 i2c_acpi_register_device(adapter, adev, &info);
 376                 break;
 377         case ACPI_RECONFIG_DEVICE_REMOVE:
 378                 if (!acpi_device_enumerated(adev))
 379                         break;
 380
 381                 client = i2c_acpi_find_client_by_adev(adev);
 382                 if (!client)
 383                         break;
 384
 385                 i2c_unregister_device(client);
 386                 put_device(&client->dev);
 387                 break;
 388         }
 389
 390         return NOTIFY_OK;
 391 }
 392
 393 struct notifier_block i2c_acpi_notifier = {
 394         .notifier_call = i2c_acpi_notify,
 395 };
 396
 397 /**
 398  * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
 399  * @dev:     Device owning the ACPI resources to get the client from
 400  * @index:   Index of ACPI resource to get
 401  * @info:    describes the I2C device; note this is modified (addr gets set)
 402  * Context: can sleep
 403  *
 404  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
 405  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
 406  * resources, in that case this function can be used to create an i2c-client
 407  * for other I2cSerialBus resources in the Current Resource Settings table.
 408  *
 409  * Also see i2c_new_device, which this function calls to create the i2c-client.
 410  *
 411  * Returns a pointer to the new i2c-client, or error pointer in case of failure.
 412  * Specifically, -EPROBE_DEFER is returned if the adapter is not found.
 413  */
 414 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 415                                        struct i2c_board_info *info)
 416 {
 417         struct i2c_acpi_lookup lookup;
 418         struct i2c_adapter *adapter;
 419         struct i2c_client *client;
 420         struct acpi_device *adev;
 421         LIST_HEAD(resource_list);
 422         int ret;
 423
 424         adev = ACPI_COMPANION(dev);
 425         if (!adev)
 426                 return ERR_PTR(-EINVAL);
 427
 428         memset(&lookup, 0, sizeof(lookup));
 429         lookup.info = info;
 430         lookup.device_handle = acpi_device_handle(adev);
 431         lookup.index = index;
 432
 433         ret = acpi_dev_get_resources(adev, &resource_list,
 434                                      i2c_acpi_fill_info, &lookup);
 435         if (ret < 0)
 436                 return ERR_PTR(ret);
 437
 438         acpi_dev_free_resource_list(&resource_list);
 439
 440         if (!info->addr)
 441                 return ERR_PTR(-EADDRNOTAVAIL);
 442
 443         adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
 444         if (!adapter)
 445                 return ERR_PTR(-EPROBE_DEFER);
 446
 447         client = i2c_new_device(adapter, info);
 448         if (!client)
 449                 return ERR_PTR(-ENODEV);
 450
 451         return client;
 452 }
 453 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 454
 455 #ifdef CONFIG_ACPI_I2C_OPREGION
 456 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 457                 u8 cmd, u8 *data, u8 data_len)
 458 {
 459
 460         struct i2c_msg msgs[2];
 461         int ret;
 462         u8 *buffer;
 463
 464         buffer = kzalloc(data_len, GFP_KERNEL);
 465         if (!buffer)
 466                 return AE_NO_MEMORY;
 467
 468         msgs[0].addr = client->addr;
 469         msgs[0].flags = client->flags;
 470         msgs[0].len = 1;
 471         msgs[0].buf = &cmd;
 472
 473         msgs[1].addr = client->addr;
 474         msgs[1].flags = client->flags | I2C_M_RD;
 475         msgs[1].len = data_len;
 476         msgs[1].buf = buffer;
 477
 478         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 479         if (ret < 0) {
 480                 /* Getting a NACK is unfortunately normal with some DSTDs */
 481                 if (ret == -EREMOTEIO)
 482                         dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
 483                                 data_len, client->addr, cmd, ret);
 484                 else
 485                         dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
 486                                 data_len, client->addr, cmd, ret);
 487         /* 2 transfers must have completed successfully */
 488         } else if (ret == 2) {
 489                 memcpy(data, buffer, data_len);
 490                 ret = 0;
 491         } else {
 492                 ret = -EIO;
 493         }
 494
 495         kfree(buffer);
 496         return ret;
 497 }
 498
 499 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
 500                 u8 cmd, u8 *data, u8 data_len)
 501 {
 502
 503         struct i2c_msg msgs[1];
 504         u8 *buffer;
 505         int ret = AE_OK;
 506
 507         buffer = kzalloc(data_len + 1, GFP_KERNEL);
 508         if (!buffer)
 509                 return AE_NO_MEMORY;
 510
 511         buffer[0] = cmd;
 512         memcpy(buffer + 1, data, data_len);
 513
 514         msgs[0].addr = client->addr;
 515         msgs[0].flags = client->flags;
 516         msgs[0].len = data_len + 1;
 517         msgs[0].buf = buffer;
 518
 519         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 520
 521         kfree(buffer);
 522
 523         if (ret < 0) {
 524                 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
 525                 return ret;
 526         }
 527
 528         /* 1 transfer must have completed successfully */
 529         return (ret == 1) ? 0 : -EIO;
 530 }
 531
 532 static acpi_status
 533 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
 534                         u32 bits, u64 *value64,
 535                         void *handler_context, void *region_context)
 536 {
 537         struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
 538         struct i2c_acpi_handler_data *data = handler_context;
 539         struct acpi_connection_info *info = &data->info;
 540         struct acpi_resource_i2c_serialbus *sb;
 541         struct i2c_adapter *adapter = data->adapter;
 542         struct i2c_client *client;
 543         struct acpi_resource *ares;
 544         u32 accessor_type = function >> 16;
 545         u8 action = function & ACPI_IO_MASK;
 546         acpi_status ret;
 547         int status;
 548
 549         ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
 550         if (ACPI_FAILURE(ret))
 551                 return ret;
 552
 553         client = kzalloc(sizeof(*client), GFP_KERNEL);
 554         if (!client) {
 555                 ret = AE_NO_MEMORY;
 556                 goto err;
 557         }
 558
 559         if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) {
 560                 ret = AE_BAD_PARAMETER;
 561                 goto err;
 562         }
 563
 564         client->adapter = adapter;
 565         client->addr = sb->slave_address;
 566
 567         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
 568                 client->flags |= I2C_CLIENT_TEN;
 569
 570         switch (accessor_type) {
 571         case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
 572                 if (action == ACPI_READ) {
 573                         status = i2c_smbus_read_byte(client);
 574                         if (status >= 0) {
 575                                 gsb->bdata = status;
 576                                 status = 0;
 577                         }
 578                 } else {
 579                         status = i2c_smbus_write_byte(client, gsb->bdata);
 580                 }
 581                 break;
 582
 583         case ACPI_GSB_ACCESS_ATTRIB_BYTE:
 584                 if (action == ACPI_READ) {
 585                         status = i2c_smbus_read_byte_data(client, command);
 586                         if (status >= 0) {
 587                                 gsb->bdata = status;
 588                                 status = 0;
 589                         }
 590                 } else {
 591                         status = i2c_smbus_write_byte_data(client, command,
 592                                         gsb->bdata);
 593                 }
 594                 break;
 595
 596         case ACPI_GSB_ACCESS_ATTRIB_WORD:
 597                 if (action == ACPI_READ) {
 598                         status = i2c_smbus_read_word_data(client, command);
 599                         if (status >= 0) {
 600                                 gsb->wdata = status;
 601                                 status = 0;
 602                         }
 603                 } else {
 604                         status = i2c_smbus_write_word_data(client, command,
 605                                         gsb->wdata);
 606                 }
 607                 break;
 608
 609         case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
 610                 if (action == ACPI_READ) {
 611                         status = i2c_smbus_read_block_data(client, command,
 612                                         gsb->data);
 613                         if (status >= 0) {
 614                                 gsb->len = status;
 615                                 status = 0;
 616                         }
 617                 } else {
 618                         status = i2c_smbus_write_block_data(client, command,
 619                                         gsb->len, gsb->data);
 620                 }
 621                 break;
 622
 623         case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
 624                 if (action == ACPI_READ) {
 625                         status = acpi_gsb_i2c_read_bytes(client, command,
 626                                         gsb->data, info->access_length);
 627                 } else {
 628                         status = acpi_gsb_i2c_write_bytes(client, command,
 629                                         gsb->data, info->access_length);
 630                 }
 631                 break;
 632
 633         default:
 634                 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
 635                          accessor_type, client->addr);
 636                 ret = AE_BAD_PARAMETER;
 637                 goto err;
 638         }
 639
 640         gsb->status = status;
 641
 642  err:
 643         kfree(client);
 644         ACPI_FREE(ares);
 645         return ret;
 646 }
 647
 648
 649 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
 650 {
 651         acpi_handle handle;
 652         struct i2c_acpi_handler_data *data;
 653         acpi_status status;
 654
 655         if (!adapter->dev.parent)
 656                 return -ENODEV;
 657
 658         handle = ACPI_HANDLE(adapter->dev.parent);
 659
 660         if (!handle)
 661                 return -ENODEV;
 662
 663         data = kzalloc(sizeof(struct i2c_acpi_handler_data),
 664                             GFP_KERNEL);
 665         if (!data)
 666                 return -ENOMEM;
 667
 668         data->adapter = adapter;
 669         status = acpi_bus_attach_private_data(handle, (void *)data);
 670         if (ACPI_FAILURE(status)) {
 671                 kfree(data);
 672                 return -ENOMEM;
 673         }
 674
 675         status = acpi_install_address_space_handler(handle,
 676                                 ACPI_ADR_SPACE_GSBUS,
 677                                 &i2c_acpi_space_handler,
 678                                 NULL,
 679                                 data);
 680         if (ACPI_FAILURE(status)) {
 681                 dev_err(&adapter->dev, "Error installing i2c space handler\n");
 682                 acpi_bus_detach_private_data(handle);
 683                 kfree(data);
 684                 return -ENOMEM;
 685         }
 686
 687         acpi_walk_dep_device_list(handle);
 688         return 0;
 689 }
 690
 691 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
 692 {
 693         acpi_handle handle;
 694         struct i2c_acpi_handler_data *data;
 695         acpi_status status;
 696
 697         if (!adapter->dev.parent)
 698                 return;
 699
 700         handle = ACPI_HANDLE(adapter->dev.parent);
 701
 702         if (!handle)
 703                 return;
 704
 705         acpi_remove_address_space_handler(handle,
 706                                 ACPI_ADR_SPACE_GSBUS,
 707                                 &i2c_acpi_space_handler);
 708
 709         status = acpi_bus_get_private_data(handle, (void **)&data);
 710         if (ACPI_SUCCESS(status))
 711                 kfree(data);
 712
 713         acpi_bus_detach_private_data(handle);
 714 }
 715 #endif /* CONFIG_ACPI_I2C_OPREGION */