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