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