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 18struct i2c_acpi_handler_data { 19 struct acpi_connection_info info; 20 struct i2c_adapter *adapter; 21}; 22 23struct gsb_buffer { 24 u8 status; 25 u8 len; 26 union { 27 u16 wdata; 28 u8 bdata; 29 u8 data[0]; 30 }; 31} __packed; 32 33struct 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 u32 force_speed; 43}; 44 45/** 46 * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches 47 * @ares: ACPI resource 48 * @i2c: Pointer to I2cSerialBus resource will be returned here 49 * 50 * Checks if the given ACPI resource is of type I2cSerialBus. 51 * In this case, returns a pointer to it to the caller. 52 * 53 * Returns true if resource type is of I2cSerialBus, otherwise false. 54 */ 55bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares, 56 struct acpi_resource_i2c_serialbus **i2c) 57{ 58 struct acpi_resource_i2c_serialbus *sb; 59 60 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) 61 return false; 62 63 sb = &ares->data.i2c_serial_bus; 64 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) 65 return false; 66 67 *i2c = sb; 68 return true; 69} 70EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource); 71 72static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data) 73{ 74 struct i2c_acpi_lookup *lookup = data; 75 struct i2c_board_info *info = lookup->info; 76 struct acpi_resource_i2c_serialbus *sb; 77 acpi_status status; 78 79 if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb)) 80 return 1; 81 82 if (lookup->index != -1 && lookup->n++ != lookup->index) 83 return 1; 84 85 status = acpi_get_handle(lookup->device_handle, 86 sb->resource_source.string_ptr, 87 &lookup->adapter_handle); 88 if (ACPI_FAILURE(status)) 89 return 1; 90 91 info->addr = sb->slave_address; 92 lookup->speed = sb->connection_speed; 93 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 94 info->flags |= I2C_CLIENT_TEN; 95 96 return 1; 97} 98 99static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = { 100 /* 101 * ACPI video acpi_devices, which are handled by the acpi-video driver 102 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these. 103 */ 104 { ACPI_VIDEO_HID, 0 }, 105 {} 106}; 107 108static int i2c_acpi_do_lookup(struct acpi_device *adev, 109 struct i2c_acpi_lookup *lookup) 110{ 111 struct i2c_board_info *info = lookup->info; 112 struct list_head resource_list; 113 int ret; 114 115 if (acpi_bus_get_status(adev) || !adev->status.present) 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 136static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data) 137{ 138 int *irq = data; 139 struct resource r; 140 141 if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r)) 142 *irq = i2c_dev_irq_from_resources(&r, 1); 143 144 return 1; /* No need to add resource to the list */ 145} 146 147/** 148 * i2c_acpi_get_irq - get device IRQ number from ACPI 149 * @client: Pointer to the I2C client device 150 * 151 * Find the IRQ number used by a specific client device. 152 * 153 * Return: The IRQ number or an error code. 154 */ 155int i2c_acpi_get_irq(struct i2c_client *client) 156{ 157 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 158 struct list_head resource_list; 159 int irq = -ENOENT; 160 int ret; 161 162 INIT_LIST_HEAD(&resource_list); 163 164 ret = acpi_dev_get_resources(adev, &resource_list, 165 i2c_acpi_add_resource, &irq); 166 if (ret < 0) 167 return ret; 168 169 acpi_dev_free_resource_list(&resource_list); 170 171 if (irq == -ENOENT) 172 irq = acpi_dev_gpio_irq_get(adev, 0); 173 174 return irq; 175} 176 177static int i2c_acpi_get_info(struct acpi_device *adev, 178 struct i2c_board_info *info, 179 struct i2c_adapter *adapter, 180 acpi_handle *adapter_handle) 181{ 182 struct i2c_acpi_lookup lookup; 183 int ret; 184 185 memset(&lookup, 0, sizeof(lookup)); 186 lookup.info = info; 187 lookup.index = -1; 188 189 if (acpi_device_enumerated(adev)) 190 return -EINVAL; 191 192 ret = i2c_acpi_do_lookup(adev, &lookup); 193 if (ret) 194 return ret; 195 196 if (adapter) { 197 /* The adapter must match the one in I2cSerialBus() connector */ 198 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle) 199 return -ENODEV; 200 } else { 201 struct acpi_device *adapter_adev; 202 203 /* The adapter must be present */ 204 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev)) 205 return -ENODEV; 206 if (acpi_bus_get_status(adapter_adev) || 207 !adapter_adev->status.present) 208 return -ENODEV; 209 } 210 211 info->fwnode = acpi_fwnode_handle(adev); 212 if (adapter_handle) 213 *adapter_handle = lookup.adapter_handle; 214 215 acpi_set_modalias(adev, dev_name(&adev->dev), info->type, 216 sizeof(info->type)); 217 218 return 0; 219} 220 221static void i2c_acpi_register_device(struct i2c_adapter *adapter, 222 struct acpi_device *adev, 223 struct i2c_board_info *info) 224{ 225 adev->power.flags.ignore_parent = true; 226 acpi_device_set_enumerated(adev); 227 228 if (IS_ERR(i2c_new_client_device(adapter, info))) { 229 adev->power.flags.ignore_parent = false; 230 dev_err(&adapter->dev, 231 "failed to add I2C device %s from ACPI\n", 232 dev_name(&adev->dev)); 233 } 234} 235 236static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level, 237 void *data, void **return_value) 238{ 239 struct i2c_adapter *adapter = data; 240 struct acpi_device *adev; 241 struct i2c_board_info info; 242 243 if (acpi_bus_get_device(handle, &adev)) 244 return AE_OK; 245 246 if (i2c_acpi_get_info(adev, &info, adapter, NULL)) 247 return AE_OK; 248 249 i2c_acpi_register_device(adapter, adev, &info); 250 251 return AE_OK; 252} 253 254#define I2C_ACPI_MAX_SCAN_DEPTH 32 255 256/** 257 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter 258 * @adap: pointer to adapter 259 * 260 * Enumerate all I2C slave devices behind this adapter by walking the ACPI 261 * namespace. When a device is found it will be added to the Linux device 262 * model and bound to the corresponding ACPI handle. 263 */ 264void i2c_acpi_register_devices(struct i2c_adapter *adap) 265{ 266 acpi_status status; 267 acpi_handle handle; 268 269 if (!has_acpi_companion(&adap->dev)) 270 return; 271 272 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 273 I2C_ACPI_MAX_SCAN_DEPTH, 274 i2c_acpi_add_device, NULL, 275 adap, NULL); 276 if (ACPI_FAILURE(status)) 277 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n"); 278 279 if (!adap->dev.parent) 280 return; 281 282 handle = ACPI_HANDLE(adap->dev.parent); 283 if (!handle) 284 return; 285 286 acpi_walk_dep_device_list(handle); 287} 288 289static const struct acpi_device_id i2c_acpi_force_400khz_device_ids[] = { 290 /* 291 * These Silead touchscreen controllers only work at 400KHz, for 292 * some reason they do not work at 100KHz. On some devices the ACPI 293 * tables list another device at their bus as only being capable 294 * of 100KHz, testing has shown that these other devices work fine 295 * at 400KHz (as can be expected of any recent i2c hw) so we force 296 * the speed of the bus to 400 KHz if a Silead device is present. 297 */ 298 { "MSSL1680", 0 }, 299 {} 300}; 301 302static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level, 303 void *data, void **return_value) 304{ 305 struct i2c_acpi_lookup *lookup = data; 306 struct acpi_device *adev; 307 308 if (acpi_bus_get_device(handle, &adev)) 309 return AE_OK; 310 311 if (i2c_acpi_do_lookup(adev, lookup)) 312 return AE_OK; 313 314 if (lookup->search_handle != lookup->adapter_handle) 315 return AE_OK; 316 317 if (lookup->speed <= lookup->min_speed) 318 lookup->min_speed = lookup->speed; 319 320 if (acpi_match_device_ids(adev, i2c_acpi_force_400khz_device_ids) == 0) 321 lookup->force_speed = I2C_MAX_FAST_MODE_FREQ; 322 323 return AE_OK; 324} 325 326/** 327 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI 328 * @dev: The device owning the bus 329 * 330 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves 331 * devices connected to this bus and use the speed of slowest device. 332 * 333 * Returns the speed in Hz or zero 334 */ 335u32 i2c_acpi_find_bus_speed(struct device *dev) 336{ 337 struct i2c_acpi_lookup lookup; 338 struct i2c_board_info dummy; 339 acpi_status status; 340 341 if (!has_acpi_companion(dev)) 342 return 0; 343 344 memset(&lookup, 0, sizeof(lookup)); 345 lookup.search_handle = ACPI_HANDLE(dev); 346 lookup.min_speed = UINT_MAX; 347 lookup.info = &dummy; 348 lookup.index = -1; 349 350 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 351 I2C_ACPI_MAX_SCAN_DEPTH, 352 i2c_acpi_lookup_speed, NULL, 353 &lookup, NULL); 354 355 if (ACPI_FAILURE(status)) { 356 dev_warn(dev, "unable to find I2C bus speed from ACPI\n"); 357 return 0; 358 } 359 360 if (lookup.force_speed) { 361 if (lookup.force_speed != lookup.min_speed) 362 dev_warn(dev, FW_BUG "DSDT uses known not-working I2C bus speed %d, forcing it to %d\n", 363 lookup.min_speed, lookup.force_speed); 364 return lookup.force_speed; 365 } else if (lookup.min_speed != UINT_MAX) { 366 return lookup.min_speed; 367 } else { 368 return 0; 369 } 370} 371EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed); 372 373static int i2c_acpi_find_match_adapter(struct device *dev, const void *data) 374{ 375 struct i2c_adapter *adapter = i2c_verify_adapter(dev); 376 377 if (!adapter) 378 return 0; 379 380 return ACPI_HANDLE(dev) == (acpi_handle)data; 381} 382 383struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle) 384{ 385 struct device *dev; 386 387 dev = bus_find_device(&i2c_bus_type, NULL, handle, 388 i2c_acpi_find_match_adapter); 389 390 return dev ? i2c_verify_adapter(dev) : NULL; 391} 392EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle); 393 394static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev) 395{ 396 struct device *dev; 397 struct i2c_client *client; 398 399 dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev); 400 if (!dev) 401 return NULL; 402 403 client = i2c_verify_client(dev); 404 if (!client) 405 put_device(dev); 406 407 return client; 408} 409 410static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value, 411 void *arg) 412{ 413 struct acpi_device *adev = arg; 414 struct i2c_board_info info; 415 acpi_handle adapter_handle; 416 struct i2c_adapter *adapter; 417 struct i2c_client *client; 418 419 switch (value) { 420 case ACPI_RECONFIG_DEVICE_ADD: 421 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle)) 422 break; 423 424 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle); 425 if (!adapter) 426 break; 427 428 i2c_acpi_register_device(adapter, adev, &info); 429 put_device(&adapter->dev); 430 break; 431 case ACPI_RECONFIG_DEVICE_REMOVE: 432 if (!acpi_device_enumerated(adev)) 433 break; 434 435 client = i2c_acpi_find_client_by_adev(adev); 436 if (!client) 437 break; 438 439 i2c_unregister_device(client); 440 put_device(&client->dev); 441 break; 442 } 443 444 return NOTIFY_OK; 445} 446 447struct notifier_block i2c_acpi_notifier = { 448 .notifier_call = i2c_acpi_notify, 449}; 450 451/** 452 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource 453 * @dev: Device owning the ACPI resources to get the client from 454 * @index: Index of ACPI resource to get 455 * @info: describes the I2C device; note this is modified (addr gets set) 456 * Context: can sleep 457 * 458 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus 459 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus 460 * resources, in that case this function can be used to create an i2c-client 461 * for other I2cSerialBus resources in the Current Resource Settings table. 462 * 463 * Also see i2c_new_client_device, which this function calls to create the 464 * i2c-client. 465 * 466 * Returns a pointer to the new i2c-client, or error pointer in case of failure. 467 * Specifically, -EPROBE_DEFER is returned if the adapter is not found. 468 */ 469struct i2c_client *i2c_acpi_new_device(struct device *dev, int index, 470 struct i2c_board_info *info) 471{ 472 struct acpi_device *adev = ACPI_COMPANION(dev); 473 struct i2c_acpi_lookup lookup; 474 struct i2c_adapter *adapter; 475 LIST_HEAD(resource_list); 476 int ret; 477 478 memset(&lookup, 0, sizeof(lookup)); 479 lookup.info = info; 480 lookup.device_handle = acpi_device_handle(adev); 481 lookup.index = index; 482 483 ret = acpi_dev_get_resources(adev, &resource_list, 484 i2c_acpi_fill_info, &lookup); 485 if (ret < 0) 486 return ERR_PTR(ret); 487 488 acpi_dev_free_resource_list(&resource_list); 489 490 if (!info->addr) 491 return ERR_PTR(-EADDRNOTAVAIL); 492 493 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle); 494 if (!adapter) 495 return ERR_PTR(-EPROBE_DEFER); 496 497 return i2c_new_client_device(adapter, info); 498} 499EXPORT_SYMBOL_GPL(i2c_acpi_new_device); 500 501#ifdef CONFIG_ACPI_I2C_OPREGION 502static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, 503 u8 cmd, u8 *data, u8 data_len) 504{ 505 506 struct i2c_msg msgs[2]; 507 int ret; 508 u8 *buffer; 509 510 buffer = kzalloc(data_len, GFP_KERNEL); 511 if (!buffer) 512 return AE_NO_MEMORY; 513 514 msgs[0].addr = client->addr; 515 msgs[0].flags = client->flags; 516 msgs[0].len = 1; 517 msgs[0].buf = &cmd; 518 519 msgs[1].addr = client->addr; 520 msgs[1].flags = client->flags | I2C_M_RD; 521 msgs[1].len = data_len; 522 msgs[1].buf = buffer; 523 524 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 525 if (ret < 0) { 526 /* Getting a NACK is unfortunately normal with some DSTDs */ 527 if (ret == -EREMOTEIO) 528 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", 529 data_len, client->addr, cmd, ret); 530 else 531 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", 532 data_len, client->addr, cmd, ret); 533 /* 2 transfers must have completed successfully */ 534 } else if (ret == 2) { 535 memcpy(data, buffer, data_len); 536 ret = 0; 537 } else { 538 ret = -EIO; 539 } 540 541 kfree(buffer); 542 return ret; 543} 544 545static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, 546 u8 cmd, u8 *data, u8 data_len) 547{ 548 549 struct i2c_msg msgs[1]; 550 u8 *buffer; 551 int ret = AE_OK; 552 553 buffer = kzalloc(data_len + 1, GFP_KERNEL); 554 if (!buffer) 555 return AE_NO_MEMORY; 556 557 buffer[0] = cmd; 558 memcpy(buffer + 1, data, data_len); 559 560 msgs[0].addr = client->addr; 561 msgs[0].flags = client->flags; 562 msgs[0].len = data_len + 1; 563 msgs[0].buf = buffer; 564 565 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 566 567 kfree(buffer); 568 569 if (ret < 0) { 570 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret); 571 return ret; 572 } 573 574 /* 1 transfer must have completed successfully */ 575 return (ret == 1) ? 0 : -EIO; 576} 577 578static acpi_status 579i2c_acpi_space_handler(u32 function, acpi_physical_address command, 580 u32 bits, u64 *value64, 581 void *handler_context, void *region_context) 582{ 583 struct gsb_buffer *gsb = (struct gsb_buffer *)value64; 584 struct i2c_acpi_handler_data *data = handler_context; 585 struct acpi_connection_info *info = &data->info; 586 struct acpi_resource_i2c_serialbus *sb; 587 struct i2c_adapter *adapter = data->adapter; 588 struct i2c_client *client; 589 struct acpi_resource *ares; 590 u32 accessor_type = function >> 16; 591 u8 action = function & ACPI_IO_MASK; 592 acpi_status ret; 593 int status; 594 595 ret = acpi_buffer_to_resource(info->connection, info->length, &ares); 596 if (ACPI_FAILURE(ret)) 597 return ret; 598 599 client = kzalloc(sizeof(*client), GFP_KERNEL); 600 if (!client) { 601 ret = AE_NO_MEMORY; 602 goto err; 603 } 604 605 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) { 606 ret = AE_BAD_PARAMETER; 607 goto err; 608 } 609 610 client->adapter = adapter; 611 client->addr = sb->slave_address; 612 613 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 614 client->flags |= I2C_CLIENT_TEN; 615 616 switch (accessor_type) { 617 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: 618 if (action == ACPI_READ) { 619 status = i2c_smbus_read_byte(client); 620 if (status >= 0) { 621 gsb->bdata = status; 622 status = 0; 623 } 624 } else { 625 status = i2c_smbus_write_byte(client, gsb->bdata); 626 } 627 break; 628 629 case ACPI_GSB_ACCESS_ATTRIB_BYTE: 630 if (action == ACPI_READ) { 631 status = i2c_smbus_read_byte_data(client, command); 632 if (status >= 0) { 633 gsb->bdata = status; 634 status = 0; 635 } 636 } else { 637 status = i2c_smbus_write_byte_data(client, command, 638 gsb->bdata); 639 } 640 break; 641 642 case ACPI_GSB_ACCESS_ATTRIB_WORD: 643 if (action == ACPI_READ) { 644 status = i2c_smbus_read_word_data(client, command); 645 if (status >= 0) { 646 gsb->wdata = status; 647 status = 0; 648 } 649 } else { 650 status = i2c_smbus_write_word_data(client, command, 651 gsb->wdata); 652 } 653 break; 654 655 case ACPI_GSB_ACCESS_ATTRIB_BLOCK: 656 if (action == ACPI_READ) { 657 status = i2c_smbus_read_block_data(client, command, 658 gsb->data); 659 if (status >= 0) { 660 gsb->len = status; 661 status = 0; 662 } 663 } else { 664 status = i2c_smbus_write_block_data(client, command, 665 gsb->len, gsb->data); 666 } 667 break; 668 669 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: 670 if (action == ACPI_READ) { 671 status = acpi_gsb_i2c_read_bytes(client, command, 672 gsb->data, info->access_length); 673 } else { 674 status = acpi_gsb_i2c_write_bytes(client, command, 675 gsb->data, info->access_length); 676 } 677 break; 678 679 default: 680 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n", 681 accessor_type, client->addr); 682 ret = AE_BAD_PARAMETER; 683 goto err; 684 } 685 686 gsb->status = status; 687 688 err: 689 kfree(client); 690 ACPI_FREE(ares); 691 return ret; 692} 693 694 695int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) 696{ 697 acpi_handle handle; 698 struct i2c_acpi_handler_data *data; 699 acpi_status status; 700 701 if (!adapter->dev.parent) 702 return -ENODEV; 703 704 handle = ACPI_HANDLE(adapter->dev.parent); 705 706 if (!handle) 707 return -ENODEV; 708 709 data = kzalloc(sizeof(struct i2c_acpi_handler_data), 710 GFP_KERNEL); 711 if (!data) 712 return -ENOMEM; 713 714 data->adapter = adapter; 715 status = acpi_bus_attach_private_data(handle, (void *)data); 716 if (ACPI_FAILURE(status)) { 717 kfree(data); 718 return -ENOMEM; 719 } 720 721 status = acpi_install_address_space_handler(handle, 722 ACPI_ADR_SPACE_GSBUS, 723 &i2c_acpi_space_handler, 724 NULL, 725 data); 726 if (ACPI_FAILURE(status)) { 727 dev_err(&adapter->dev, "Error installing i2c space handler\n"); 728 acpi_bus_detach_private_data(handle); 729 kfree(data); 730 return -ENOMEM; 731 } 732 733 return 0; 734} 735 736void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) 737{ 738 acpi_handle handle; 739 struct i2c_acpi_handler_data *data; 740 acpi_status status; 741 742 if (!adapter->dev.parent) 743 return; 744 745 handle = ACPI_HANDLE(adapter->dev.parent); 746 747 if (!handle) 748 return; 749 750 acpi_remove_address_space_handler(handle, 751 ACPI_ADR_SPACE_GSBUS, 752 &i2c_acpi_space_handler); 753 754 status = acpi_bus_get_private_data(handle, (void **)&data); 755 if (ACPI_SUCCESS(status)) 756 kfree(data); 757 758 acpi_bus_detach_private_data(handle); 759} 760#endif /* CONFIG_ACPI_I2C_OPREGION */ 761