drivers/i2c/i2c-core-acpi.c

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