drivers/i2c/i2c-core-acpi.c

   1 /*
   2  * Linux I2C core ACPI support code
   3  *
   4  * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com>
   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         u32 force_speed;
  47 };
  48
  49 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data)
  50 {
  51         struct i2c_acpi_lookup *lookup = data;
  52         struct i2c_board_info *info = lookup->info;
  53         struct acpi_resource_i2c_serialbus *sb;
  54         acpi_status status;
  55
  56         if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
  57                 return 1;
  58
  59         sb = &ares->data.i2c_serial_bus;
  60         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
  61                 return 1;
  62
  63         if (lookup->index != -1 && lookup->n++ != lookup->index)
  64                 return 1;
  65
  66         status = acpi_get_handle(lookup->device_handle,
  67                                  sb->resource_source.string_ptr,
  68                                  &lookup->adapter_handle);
  69         if (!ACPI_SUCCESS(status))
  70                 return 1;
  71
  72         info->addr = sb->slave_address;
  73         lookup->speed = sb->connection_speed;
  74         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
  75                 info->flags |= I2C_CLIENT_TEN;
  76
  77         return 1;
  78 }
  79
  80 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = {
  81         /*
  82          * ACPI video acpi_devices, which are handled by the acpi-video driver
  83          * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these.
  84          */
  85         { ACPI_VIDEO_HID, 0 },
  86         {}
  87 };
  88
  89 static int i2c_acpi_do_lookup(struct acpi_device *adev,
  90                               struct i2c_acpi_lookup *lookup)
  91 {
  92         struct i2c_board_info *info = lookup->info;
  93         struct list_head resource_list;
  94         int ret;
  95
  96         if (acpi_bus_get_status(adev) || !adev->status.present ||
  97             acpi_device_enumerated(adev))
  98                 return -EINVAL;
  99
 100         if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0)
 101                 return -ENODEV;
 102
 103         memset(info, 0, sizeof(*info));
 104         lookup->device_handle = acpi_device_handle(adev);
 105
 106         /* Look up for I2cSerialBus resource */
 107         INIT_LIST_HEAD(&resource_list);
 108         ret = acpi_dev_get_resources(adev, &resource_list,
 109                                      i2c_acpi_fill_info, lookup);
 110         acpi_dev_free_resource_list(&resource_list);
 111
 112         if (ret < 0 || !info->addr)
 113                 return -EINVAL;
 114
 115         return 0;
 116 }
 117
 118 static int i2c_acpi_get_info(struct acpi_device *adev,
 119                              struct i2c_board_info *info,
 120                              struct i2c_adapter *adapter,
 121                              acpi_handle *adapter_handle)
 122 {
 123         struct list_head resource_list;
 124         struct resource_entry *entry;
 125         struct i2c_acpi_lookup lookup;
 126         int ret;
 127
 128         memset(&lookup, 0, sizeof(lookup));
 129         lookup.info = info;
 130         lookup.index = -1;
 131
 132         ret = i2c_acpi_do_lookup(adev, &lookup);
 133         if (ret)
 134                 return ret;
 135
 136         if (adapter) {
 137                 /* The adapter must match the one in I2cSerialBus() connector */
 138                 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle)
 139                         return -ENODEV;
 140         } else {
 141                 struct acpi_device *adapter_adev;
 142
 143                 /* The adapter must be present */
 144                 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev))
 145                         return -ENODEV;
 146                 if (acpi_bus_get_status(adapter_adev) ||
 147                     !adapter_adev->status.present)
 148                         return -ENODEV;
 149         }
 150
 151         info->fwnode = acpi_fwnode_handle(adev);
 152         if (adapter_handle)
 153                 *adapter_handle = lookup.adapter_handle;
 154
 155         /* Then fill IRQ number if any */
 156         INIT_LIST_HEAD(&resource_list);
 157         ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
 158         if (ret < 0)
 159                 return -EINVAL;
 160
 161         resource_list_for_each_entry(entry, &resource_list) {
 162                 if (resource_type(entry->res) == IORESOURCE_IRQ) {
 163                         info->irq = entry->res->start;
 164                         break;
 165                 }
 166         }
 167
 168         acpi_dev_free_resource_list(&resource_list);
 169
 170         acpi_set_modalias(adev, dev_name(&adev->dev), info->type,
 171                           sizeof(info->type));
 172
 173         return 0;
 174 }
 175
 176 static void i2c_acpi_register_device(struct i2c_adapter *adapter,
 177                                      struct acpi_device *adev,
 178                                      struct i2c_board_info *info)
 179 {
 180         adev->power.flags.ignore_parent = true;
 181         acpi_device_set_enumerated(adev);
 182
 183         if (!i2c_new_device(adapter, info)) {
 184                 adev->power.flags.ignore_parent = false;
 185                 dev_err(&adapter->dev,
 186                         "failed to add I2C device %s from ACPI\n",
 187                         dev_name(&adev->dev));
 188         }
 189 }
 190
 191 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level,
 192                                        void *data, void **return_value)
 193 {
 194         struct i2c_adapter *adapter = data;
 195         struct acpi_device *adev;
 196         struct i2c_board_info info;
 197
 198         if (acpi_bus_get_device(handle, &adev))
 199                 return AE_OK;
 200
 201         if (i2c_acpi_get_info(adev, &info, adapter, NULL))
 202                 return AE_OK;
 203
 204         i2c_acpi_register_device(adapter, adev, &info);
 205
 206         return AE_OK;
 207 }
 208
 209 #define I2C_ACPI_MAX_SCAN_DEPTH 32
 210
 211 /**
 212  * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter
 213  * @adap: pointer to adapter
 214  *
 215  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 216  * namespace. When a device is found it will be added to the Linux device
 217  * model and bound to the corresponding ACPI handle.
 218  */
 219 void i2c_acpi_register_devices(struct i2c_adapter *adap)
 220 {
 221         acpi_status status;
 222         acpi_handle handle;
 223
 224         if (!has_acpi_companion(&adap->dev))
 225                 return;
 226
 227         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 228                                      I2C_ACPI_MAX_SCAN_DEPTH,
 229                                      i2c_acpi_add_device, NULL,
 230                                      adap, NULL);
 231         if (ACPI_FAILURE(status))
 232                 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 233
 234         if (!adap->dev.parent)
 235                 return;
 236
 237         handle = ACPI_HANDLE(adap->dev.parent);
 238         if (!handle)
 239                 return;
 240
 241         acpi_walk_dep_device_list(handle);
 242 }
 243
 244 const struct acpi_device_id *
 245 i2c_acpi_match_device(const struct acpi_device_id *matches,
 246                       struct i2c_client *client)
 247 {
 248         if (!(client && matches))
 249                 return NULL;
 250
 251         return acpi_match_device(matches, &client->dev);
 252 }
 253
 254 static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = {
 255         /*
 256          * These Silead touchscreen controllers only work at 400KHz, for
 257          * some reason they do not work at 100KHz. On some devices the ACPI
 258          * tables list another device at their bus as only being capable
 259          * of 100KHz, testing has shown that these other devices work fine
 260          * at 400KHz (as can be expected of any recent i2c hw) so we force
 261          * the speed of the bus to 400 KHz if a Silead device is present.
 262          */
 263         { "MSSL1680", 0 },
 264         {}
 265 };
 266
 267 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
 268                                            void *data, void **return_value)
 269 {
 270         struct i2c_acpi_lookup *lookup = data;
 271         struct acpi_device *adev;
 272
 273         if (acpi_bus_get_device(handle, &adev))
 274                 return AE_OK;
 275
 276         if (i2c_acpi_do_lookup(adev, lookup))
 277                 return AE_OK;
 278
 279         if (lookup->search_handle != lookup->adapter_handle)
 280                 return AE_OK;
 281
 282         if (lookup->speed <= lookup->min_speed)
 283                 lookup->min_speed = lookup->speed;
 284
 285         if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0)
 286                 lookup->force_speed = 400000;
 287
 288         return AE_OK;
 289 }
 290
 291 /**
 292  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
 293  * @dev: The device owning the bus
 294  *
 295  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
 296  * devices connected to this bus and use the speed of slowest device.
 297  *
 298  * Returns the speed in Hz or zero
 299  */
 300 u32 i2c_acpi_find_bus_speed(struct device *dev)
 301 {
 302         struct i2c_acpi_lookup lookup;
 303         struct i2c_board_info dummy;
 304         acpi_status status;
 305
 306         if (!has_acpi_companion(dev))
 307                 return 0;
 308
 309         memset(&lookup, 0, sizeof(lookup));
 310         lookup.search_handle = ACPI_HANDLE(dev);
 311         lookup.min_speed = UINT_MAX;
 312         lookup.info = &dummy;
 313         lookup.index = -1;
 314
 315         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 316                                      I2C_ACPI_MAX_SCAN_DEPTH,
 317                                      i2c_acpi_lookup_speed, NULL,
 318                                      &lookup, NULL);
 319
 320         if (ACPI_FAILURE(status)) {
 321                 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
 322                 return 0;
 323         }
 324
 325         if (lookup.force_speed) {
 326                 if (lookup.force_speed != lookup.min_speed)
 327                         dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n",
 328                                  lookup.min_speed, lookup.force_speed);
 329                 return lookup.force_speed;
 330         } else if (lookup.min_speed != UINT_MAX) {
 331                 return lookup.min_speed;
 332         } else {
 333                 return 0;
 334         }
 335 }
 336 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
 337
 338 static int i2c_acpi_find_match_adapter(struct device *dev, void *data)
 339 {
 340         struct i2c_adapter *adapter = i2c_verify_adapter(dev);
 341
 342         if (!adapter)
 343                 return 0;
 344
 345         return ACPI_HANDLE(dev) == (acpi_handle)data;
 346 }
 347
 348 static int i2c_acpi_find_match_device(struct device *dev, void *data)
 349 {
 350         return ACPI_COMPANION(dev) == data;
 351 }
 352
 353 static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
 354 {
 355         struct device *dev;
 356
 357         dev = bus_find_device(&i2c_bus_type, NULL, handle,
 358                               i2c_acpi_find_match_adapter);
 359         return dev ? i2c_verify_adapter(dev) : NULL;
 360 }
 361
 362 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
 363 {
 364         struct device *dev;
 365         struct i2c_client *client;
 366
 367         dev = bus_find_device(&i2c_bus_type, NULL, adev,
 368                               i2c_acpi_find_match_device);
 369         if (!dev)
 370                 return NULL;
 371
 372         client = i2c_verify_client(dev);
 373         if (!client)
 374                 put_device(dev);
 375
 376         return client;
 377 }
 378
 379 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
 380                            void *arg)
 381 {
 382         struct acpi_device *adev = arg;
 383         struct i2c_board_info info;
 384         acpi_handle adapter_handle;
 385         struct i2c_adapter *adapter;
 386         struct i2c_client *client;
 387
 388         switch (value) {
 389         case ACPI_RECONFIG_DEVICE_ADD:
 390                 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
 391                         break;
 392
 393                 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
 394                 if (!adapter)
 395                         break;
 396
 397                 i2c_acpi_register_device(adapter, adev, &info);
 398                 put_device(&adapter->dev);
 399                 break;
 400         case ACPI_RECONFIG_DEVICE_REMOVE:
 401                 if (!acpi_device_enumerated(adev))
 402                         break;
 403
 404                 client = i2c_acpi_find_client_by_adev(adev);
 405                 if (!client)
 406                         break;
 407
 408                 i2c_unregister_device(client);
 409                 put_device(&client->dev);
 410                 break;
 411         }
 412
 413         return NOTIFY_OK;
 414 }
 415
 416 struct notifier_block i2c_acpi_notifier = {
 417         .notifier_call = i2c_acpi_notify,
 418 };
 419
 420 /**
 421  * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
 422  * @dev:     Device owning the ACPI resources to get the client from
 423  * @index:   Index of ACPI resource to get
 424  * @info:    describes the I2C device; note this is modified (addr gets set)
 425  * Context: can sleep
 426  *
 427  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
 428  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
 429  * resources, in that case this function can be used to create an i2c-client
 430  * for other I2cSerialBus resources in the Current Resource Settings table.
 431  *
 432  * Also see i2c_new_device, which this function calls to create the i2c-client.
 433  *
 434  * Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
 435  */
 436 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 437                                        struct i2c_board_info *info)
 438 {
 439         struct i2c_acpi_lookup lookup;
 440         struct i2c_adapter *adapter;
 441         struct acpi_device *adev;
 442         LIST_HEAD(resource_list);
 443         int ret;
 444
 445         adev = ACPI_COMPANION(dev);
 446         if (!adev)
 447                 return NULL;
 448
 449         memset(&lookup, 0, sizeof(lookup));
 450         lookup.info = info;
 451         lookup.device_handle = acpi_device_handle(adev);
 452         lookup.index = index;
 453
 454         ret = acpi_dev_get_resources(adev, &resource_list,
 455                                      i2c_acpi_fill_info, &lookup);
 456         acpi_dev_free_resource_list(&resource_list);
 457
 458         if (ret < 0 || !info->addr)
 459                 return NULL;
 460
 461         adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
 462         if (!adapter)
 463                 return NULL;
 464
 465         return i2c_new_device(adapter, info);
 466 }
 467 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 468
 469 #ifdef CONFIG_ACPI_I2C_OPREGION
 470 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 471                 u8 cmd, u8 *data, u8 data_len)
 472 {
 473
 474         struct i2c_msg msgs[2];
 475         int ret;
 476         u8 *buffer;
 477
 478         buffer = kzalloc(data_len, GFP_KERNEL);
 479         if (!buffer)
 480                 return AE_NO_MEMORY;
 481
 482         msgs[0].addr = client->addr;
 483         msgs[0].flags = client->flags;
 484         msgs[0].len = 1;
 485         msgs[0].buf = &cmd;
 486
 487         msgs[1].addr = client->addr;
 488         msgs[1].flags = client->flags | I2C_M_RD;
 489         msgs[1].len = data_len;
 490         msgs[1].buf = buffer;
 491
 492         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 493         if (ret < 0) {
 494                 /* Getting a NACK is unfortunately normal with some DSTDs */
 495                 if (ret == -EREMOTEIO)
 496                         dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
 497                                 data_len, client->addr, cmd, ret);
 498                 else
 499                         dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n",
 500                                 data_len, client->addr, cmd, ret);
 501         /* 2 transfers must have completed successfully */
 502         } else if (ret == 2) {
 503                 memcpy(data, buffer, data_len);
 504                 ret = 0;
 505         } else {
 506                 ret = -EIO;
 507         }
 508
 509         kfree(buffer);
 510         return ret;
 511 }
 512
 513 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
 514                 u8 cmd, u8 *data, u8 data_len)
 515 {
 516
 517         struct i2c_msg msgs[1];
 518         u8 *buffer;
 519         int ret = AE_OK;
 520
 521         buffer = kzalloc(data_len + 1, GFP_KERNEL);
 522         if (!buffer)
 523                 return AE_NO_MEMORY;
 524
 525         buffer[0] = cmd;
 526         memcpy(buffer + 1, data, data_len);
 527
 528         msgs[0].addr = client->addr;
 529         msgs[0].flags = client->flags;
 530         msgs[0].len = data_len + 1;
 531         msgs[0].buf = buffer;
 532
 533         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 534
 535         kfree(buffer);
 536
 537         if (ret < 0) {
 538                 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret);
 539                 return ret;
 540         }
 541
 542         /* 1 transfer must have completed successfully */
 543         return (ret == 1) ? 0 : -EIO;
 544 }
 545
 546 static acpi_status
 547 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
 548                         u32 bits, u64 *value64,
 549                         void *handler_context, void *region_context)
 550 {
 551         struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
 552         struct i2c_acpi_handler_data *data = handler_context;
 553         struct acpi_connection_info *info = &data->info;
 554         struct acpi_resource_i2c_serialbus *sb;
 555         struct i2c_adapter *adapter = data->adapter;
 556         struct i2c_client *client;
 557         struct acpi_resource *ares;
 558         u32 accessor_type = function >> 16;
 559         u8 action = function & ACPI_IO_MASK;
 560         acpi_status ret;
 561         int status;
 562
 563         ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
 564         if (ACPI_FAILURE(ret))
 565                 return ret;
 566
 567         client = kzalloc(sizeof(*client), GFP_KERNEL);
 568         if (!client) {
 569                 ret = AE_NO_MEMORY;
 570                 goto err;
 571         }
 572
 573         if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
 574                 ret = AE_BAD_PARAMETER;
 575                 goto err;
 576         }
 577
 578         sb = &ares->data.i2c_serial_bus;
 579         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
 580                 ret = AE_BAD_PARAMETER;
 581                 goto err;
 582         }
 583
 584         client->adapter = adapter;
 585         client->addr = sb->slave_address;
 586
 587         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
 588                 client->flags |= I2C_CLIENT_TEN;
 589
 590         switch (accessor_type) {
 591         case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
 592                 if (action == ACPI_READ) {
 593                         status = i2c_smbus_read_byte(client);
 594                         if (status >= 0) {
 595                                 gsb->bdata = status;
 596                                 status = 0;
 597                         }
 598                 } else {
 599                         status = i2c_smbus_write_byte(client, gsb->bdata);
 600                 }
 601                 break;
 602
 603         case ACPI_GSB_ACCESS_ATTRIB_BYTE:
 604                 if (action == ACPI_READ) {
 605                         status = i2c_smbus_read_byte_data(client, command);
 606                         if (status >= 0) {
 607                                 gsb->bdata = status;
 608                                 status = 0;
 609                         }
 610                 } else {
 611                         status = i2c_smbus_write_byte_data(client, command,
 612                                         gsb->bdata);
 613                 }
 614                 break;
 615
 616         case ACPI_GSB_ACCESS_ATTRIB_WORD:
 617                 if (action == ACPI_READ) {
 618                         status = i2c_smbus_read_word_data(client, command);
 619                         if (status >= 0) {
 620                                 gsb->wdata = status;
 621                                 status = 0;
 622                         }
 623                 } else {
 624                         status = i2c_smbus_write_word_data(client, command,
 625                                         gsb->wdata);
 626                 }
 627                 break;
 628
 629         case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
 630                 if (action == ACPI_READ) {
 631                         status = i2c_smbus_read_block_data(client, command,
 632                                         gsb->data);
 633                         if (status >= 0) {
 634                                 gsb->len = status;
 635                                 status = 0;
 636                         }
 637                 } else {
 638                         status = i2c_smbus_write_block_data(client, command,
 639                                         gsb->len, gsb->data);
 640                 }
 641                 break;
 642
 643         case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
 644                 if (action == ACPI_READ) {
 645                         status = acpi_gsb_i2c_read_bytes(client, command,
 646                                         gsb->data, info->access_length);
 647                 } else {
 648                         status = acpi_gsb_i2c_write_bytes(client, command,
 649                                         gsb->data, info->access_length);
 650                 }
 651                 break;
 652
 653         default:
 654                 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
 655                          accessor_type, client->addr);
 656                 ret = AE_BAD_PARAMETER;
 657                 goto err;
 658         }
 659
 660         gsb->status = status;
 661
 662  err:
 663         kfree(client);
 664         ACPI_FREE(ares);
 665         return ret;
 666 }
 667
 668
 669 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
 670 {
 671         acpi_handle handle;
 672         struct i2c_acpi_handler_data *data;
 673         acpi_status status;
 674
 675         if (!adapter->dev.parent)
 676                 return -ENODEV;
 677
 678         handle = ACPI_HANDLE(adapter->dev.parent);
 679
 680         if (!handle)
 681                 return -ENODEV;
 682
 683         data = kzalloc(sizeof(struct i2c_acpi_handler_data),
 684                             GFP_KERNEL);
 685         if (!data)
 686                 return -ENOMEM;
 687
 688         data->adapter = adapter;
 689         status = acpi_bus_attach_private_data(handle, (void *)data);
 690         if (ACPI_FAILURE(status)) {
 691                 kfree(data);
 692                 return -ENOMEM;
 693         }
 694
 695         status = acpi_install_address_space_handler(handle,
 696                                 ACPI_ADR_SPACE_GSBUS,
 697                                 &i2c_acpi_space_handler,
 698                                 NULL,
 699                                 data);
 700         if (ACPI_FAILURE(status)) {
 701                 dev_err(&adapter->dev, "Error installing i2c space handler\n");
 702                 acpi_bus_detach_private_data(handle);
 703                 kfree(data);
 704                 return -ENOMEM;
 705         }
 706
 707         return 0;
 708 }
 709
 710 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
 711 {
 712         acpi_handle handle;
 713         struct i2c_acpi_handler_data *data;
 714         acpi_status status;
 715
 716         if (!adapter->dev.parent)
 717                 return;
 718
 719         handle = ACPI_HANDLE(adapter->dev.parent);
 720
 721         if (!handle)
 722                 return;
 723
 724         acpi_remove_address_space_handler(handle,
 725                                 ACPI_ADR_SPACE_GSBUS,
 726                                 &i2c_acpi_space_handler);
 727
 728         status = acpi_bus_get_private_data(handle, (void **)&data);
 729         if (ACPI_SUCCESS(status))
 730                 kfree(data);
 731
 732         acpi_bus_detach_private_data(handle);
 733 }
 734 #endif /* CONFIG_ACPI_I2C_OPREGION */