1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux I2C core ACPI support code 4 * 5 * Copyright (C) 2014 Intel Corp, Author: Lan Tianyu <tianyu.lan@intel.com> 6 */ 7 8 #include <linux/acpi.h> 9 #include <linux/device.h> 10 #include <linux/err.h> 11 #include <linux/i2c.h> 12 #include <linux/list.h> 13 #include <linux/module.h> 14 #include <linux/slab.h> 15 16 #include "i2c-core.h" 17 18 struct i2c_acpi_handler_data { 19 struct acpi_connection_info info; 20 struct i2c_adapter *adapter; 21 }; 22 23 struct gsb_buffer { 24 u8 status; 25 u8 len; 26 union { 27 u16 wdata; 28 u8 bdata; 29 u8 data[0]; 30 }; 31 } __packed; 32 33 struct i2c_acpi_lookup { 34 struct i2c_board_info *info; 35 acpi_handle adapter_handle; 36 acpi_handle device_handle; 37 acpi_handle search_handle; 38 int n; 39 int index; 40 u32 speed; 41 u32 min_speed; 42 }; 43 44 /** 45 * i2c_acpi_get_i2c_resource - Gets I2cSerialBus resource if type matches 46 * @ares: ACPI resource 47 * @i2c: Pointer to I2cSerialBus resource will be returned here 48 * 49 * Checks if the given ACPI resource is of type I2cSerialBus. 50 * In this case, returns a pointer to it to the caller. 51 * 52 * Returns true if resource type is of I2cSerialBus, otherwise false. 53 */ 54 bool i2c_acpi_get_i2c_resource(struct acpi_resource *ares, 55 struct acpi_resource_i2c_serialbus **i2c) 56 { 57 struct acpi_resource_i2c_serialbus *sb; 58 59 if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) 60 return false; 61 62 sb = &ares->data.i2c_serial_bus; 63 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) 64 return false; 65 66 *i2c = sb; 67 return true; 68 } 69 EXPORT_SYMBOL_GPL(i2c_acpi_get_i2c_resource); 70 71 static int i2c_acpi_fill_info(struct acpi_resource *ares, void *data) 72 { 73 struct i2c_acpi_lookup *lookup = data; 74 struct i2c_board_info *info = lookup->info; 75 struct acpi_resource_i2c_serialbus *sb; 76 acpi_status status; 77 78 if (info->addr || !i2c_acpi_get_i2c_resource(ares, &sb)) 79 return 1; 80 81 if (lookup->index != -1 && lookup->n++ != lookup->index) 82 return 1; 83 84 status = acpi_get_handle(lookup->device_handle, 85 sb->resource_source.string_ptr, 86 &lookup->adapter_handle); 87 if (ACPI_FAILURE(status)) 88 return 1; 89 90 info->addr = sb->slave_address; 91 lookup->speed = sb->connection_speed; 92 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 93 info->flags |= I2C_CLIENT_TEN; 94 95 return 1; 96 } 97 98 static const struct acpi_device_id i2c_acpi_ignored_device_ids[] = { 99 /* 100 * ACPI video acpi_devices, which are handled by the acpi-video driver 101 * sometimes contain a SERIAL_TYPE_I2C ACPI resource, ignore these. 102 */ 103 { ACPI_VIDEO_HID, 0 }, 104 {} 105 }; 106 107 static int i2c_acpi_do_lookup(struct acpi_device *adev, 108 struct i2c_acpi_lookup *lookup) 109 { 110 struct i2c_board_info *info = lookup->info; 111 struct list_head resource_list; 112 int ret; 113 114 if (acpi_bus_get_status(adev) || !adev->status.present) 115 return -EINVAL; 116 117 if (acpi_match_device_ids(adev, i2c_acpi_ignored_device_ids) == 0) 118 return -ENODEV; 119 120 memset(info, 0, sizeof(*info)); 121 lookup->device_handle = acpi_device_handle(adev); 122 123 /* Look up for I2cSerialBus resource */ 124 INIT_LIST_HEAD(&resource_list); 125 ret = acpi_dev_get_resources(adev, &resource_list, 126 i2c_acpi_fill_info, lookup); 127 acpi_dev_free_resource_list(&resource_list); 128 129 if (ret < 0 || !info->addr) 130 return -EINVAL; 131 132 return 0; 133 } 134 135 static int i2c_acpi_add_resource(struct acpi_resource *ares, void *data) 136 { 137 int *irq = data; 138 struct resource r; 139 140 if (*irq <= 0 && acpi_dev_resource_interrupt(ares, 0, &r)) 141 *irq = i2c_dev_irq_from_resources(&r, 1); 142 143 return 1; /* No need to add resource to the list */ 144 } 145 146 /** 147 * i2c_acpi_get_irq - get device IRQ number from ACPI 148 * @client: Pointer to the I2C client device 149 * 150 * Find the IRQ number used by a specific client device. 151 * 152 * Return: The IRQ number or an error code. 153 */ 154 int i2c_acpi_get_irq(struct i2c_client *client) 155 { 156 struct acpi_device *adev = ACPI_COMPANION(&client->dev); 157 struct list_head resource_list; 158 int irq = -ENOENT; 159 int ret; 160 161 INIT_LIST_HEAD(&resource_list); 162 163 ret = acpi_dev_get_resources(adev, &resource_list, 164 i2c_acpi_add_resource, &irq); 165 if (ret < 0) 166 return ret; 167 168 acpi_dev_free_resource_list(&resource_list); 169 170 if (irq == -ENOENT) 171 irq = acpi_dev_gpio_irq_get(adev, 0); 172 173 return irq; 174 } 175 176 static int i2c_acpi_get_info(struct acpi_device *adev, 177 struct i2c_board_info *info, 178 struct i2c_adapter *adapter, 179 acpi_handle *adapter_handle) 180 { 181 struct i2c_acpi_lookup lookup; 182 int ret; 183 184 memset(&lookup, 0, sizeof(lookup)); 185 lookup.info = info; 186 lookup.index = -1; 187 188 if (acpi_device_enumerated(adev)) 189 return -EINVAL; 190 191 ret = i2c_acpi_do_lookup(adev, &lookup); 192 if (ret) 193 return ret; 194 195 if (adapter) { 196 /* The adapter must match the one in I2cSerialBus() connector */ 197 if (ACPI_HANDLE(&adapter->dev) != lookup.adapter_handle) 198 return -ENODEV; 199 } else { 200 struct acpi_device *adapter_adev; 201 202 /* The adapter must be present */ 203 if (acpi_bus_get_device(lookup.adapter_handle, &adapter_adev)) 204 return -ENODEV; 205 if (acpi_bus_get_status(adapter_adev) || 206 !adapter_adev->status.present) 207 return -ENODEV; 208 } 209 210 info->fwnode = acpi_fwnode_handle(adev); 211 if (adapter_handle) 212 *adapter_handle = lookup.adapter_handle; 213 214 acpi_set_modalias(adev, dev_name(&adev->dev), info->type, 215 sizeof(info->type)); 216 217 return 0; 218 } 219 220 static void i2c_acpi_register_device(struct i2c_adapter *adapter, 221 struct acpi_device *adev, 222 struct i2c_board_info *info) 223 { 224 adev->power.flags.ignore_parent = true; 225 acpi_device_set_enumerated(adev); 226 227 if (!i2c_new_device(adapter, info)) { 228 adev->power.flags.ignore_parent = false; 229 dev_err(&adapter->dev, 230 "failed to add I2C device %s from ACPI\n", 231 dev_name(&adev->dev)); 232 } 233 } 234 235 static acpi_status i2c_acpi_add_device(acpi_handle handle, u32 level, 236 void *data, void **return_value) 237 { 238 struct i2c_adapter *adapter = data; 239 struct acpi_device *adev; 240 struct i2c_board_info info; 241 242 if (acpi_bus_get_device(handle, &adev)) 243 return AE_OK; 244 245 if (i2c_acpi_get_info(adev, &info, adapter, NULL)) 246 return AE_OK; 247 248 i2c_acpi_register_device(adapter, adev, &info); 249 250 return AE_OK; 251 } 252 253 #define I2C_ACPI_MAX_SCAN_DEPTH 32 254 255 /** 256 * i2c_acpi_register_devices - enumerate I2C slave devices behind adapter 257 * @adap: pointer to adapter 258 * 259 * Enumerate all I2C slave devices behind this adapter by walking the ACPI 260 * namespace. When a device is found it will be added to the Linux device 261 * model and bound to the corresponding ACPI handle. 262 */ 263 void i2c_acpi_register_devices(struct i2c_adapter *adap) 264 { 265 acpi_status status; 266 267 if (!has_acpi_companion(&adap->dev)) 268 return; 269 270 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 271 I2C_ACPI_MAX_SCAN_DEPTH, 272 i2c_acpi_add_device, NULL, 273 adap, NULL); 274 if (ACPI_FAILURE(status)) 275 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n"); 276 } 277 278 const struct acpi_device_id * 279 i2c_acpi_match_device(const struct acpi_device_id *matches, 280 struct i2c_client *client) 281 { 282 if (!(client && matches)) 283 return NULL; 284 285 return acpi_match_device(matches, &client->dev); 286 } 287 288 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level, 289 void *data, void **return_value) 290 { 291 struct i2c_acpi_lookup *lookup = data; 292 struct acpi_device *adev; 293 294 if (acpi_bus_get_device(handle, &adev)) 295 return AE_OK; 296 297 if (i2c_acpi_do_lookup(adev, lookup)) 298 return AE_OK; 299 300 if (lookup->search_handle != lookup->adapter_handle) 301 return AE_OK; 302 303 if (lookup->speed <= lookup->min_speed) 304 lookup->min_speed = lookup->speed; 305 306 return AE_OK; 307 } 308 309 /** 310 * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI 311 * @dev: The device owning the bus 312 * 313 * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves 314 * devices connected to this bus and use the speed of slowest device. 315 * 316 * Returns the speed in Hz or zero 317 */ 318 u32 i2c_acpi_find_bus_speed(struct device *dev) 319 { 320 struct i2c_acpi_lookup lookup; 321 struct i2c_board_info dummy; 322 acpi_status status; 323 324 if (!has_acpi_companion(dev)) 325 return 0; 326 327 memset(&lookup, 0, sizeof(lookup)); 328 lookup.search_handle = ACPI_HANDLE(dev); 329 lookup.min_speed = UINT_MAX; 330 lookup.info = &dummy; 331 lookup.index = -1; 332 333 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 334 I2C_ACPI_MAX_SCAN_DEPTH, 335 i2c_acpi_lookup_speed, NULL, 336 &lookup, NULL); 337 338 if (ACPI_FAILURE(status)) { 339 dev_warn(dev, "unable to find I2C bus speed from ACPI\n"); 340 return 0; 341 } 342 343 return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0; 344 } 345 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed); 346 347 static int i2c_acpi_find_match_adapter(struct device *dev, const void *data) 348 { 349 struct i2c_adapter *adapter = i2c_verify_adapter(dev); 350 351 if (!adapter) 352 return 0; 353 354 return ACPI_HANDLE(dev) == (acpi_handle)data; 355 } 356 357 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle) 358 { 359 struct device *dev; 360 361 dev = bus_find_device(&i2c_bus_type, NULL, handle, 362 i2c_acpi_find_match_adapter); 363 364 return dev ? i2c_verify_adapter(dev) : NULL; 365 } 366 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle); 367 368 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev) 369 { 370 struct device *dev; 371 372 dev = bus_find_device_by_acpi_dev(&i2c_bus_type, adev); 373 return dev ? i2c_verify_client(dev) : NULL; 374 } 375 376 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value, 377 void *arg) 378 { 379 struct acpi_device *adev = arg; 380 struct i2c_board_info info; 381 acpi_handle adapter_handle; 382 struct i2c_adapter *adapter; 383 struct i2c_client *client; 384 385 switch (value) { 386 case ACPI_RECONFIG_DEVICE_ADD: 387 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle)) 388 break; 389 390 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle); 391 if (!adapter) 392 break; 393 394 i2c_acpi_register_device(adapter, adev, &info); 395 break; 396 case ACPI_RECONFIG_DEVICE_REMOVE: 397 if (!acpi_device_enumerated(adev)) 398 break; 399 400 client = i2c_acpi_find_client_by_adev(adev); 401 if (!client) 402 break; 403 404 i2c_unregister_device(client); 405 put_device(&client->dev); 406 break; 407 } 408 409 return NOTIFY_OK; 410 } 411 412 struct notifier_block i2c_acpi_notifier = { 413 .notifier_call = i2c_acpi_notify, 414 }; 415 416 /** 417 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource 418 * @dev: Device owning the ACPI resources to get the client from 419 * @index: Index of ACPI resource to get 420 * @info: describes the I2C device; note this is modified (addr gets set) 421 * Context: can sleep 422 * 423 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus 424 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus 425 * resources, in that case this function can be used to create an i2c-client 426 * for other I2cSerialBus resources in the Current Resource Settings table. 427 * 428 * Also see i2c_new_device, which this function calls to create the i2c-client. 429 * 430 * Returns a pointer to the new i2c-client, or error pointer in case of failure. 431 * Specifically, -EPROBE_DEFER is returned if the adapter is not found. 432 */ 433 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index, 434 struct i2c_board_info *info) 435 { 436 struct i2c_acpi_lookup lookup; 437 struct i2c_adapter *adapter; 438 struct i2c_client *client; 439 struct acpi_device *adev; 440 LIST_HEAD(resource_list); 441 int ret; 442 443 adev = ACPI_COMPANION(dev); 444 if (!adev) 445 return ERR_PTR(-EINVAL); 446 447 memset(&lookup, 0, sizeof(lookup)); 448 lookup.info = info; 449 lookup.device_handle = acpi_device_handle(adev); 450 lookup.index = index; 451 452 ret = acpi_dev_get_resources(adev, &resource_list, 453 i2c_acpi_fill_info, &lookup); 454 if (ret < 0) 455 return ERR_PTR(ret); 456 457 acpi_dev_free_resource_list(&resource_list); 458 459 if (!info->addr) 460 return ERR_PTR(-EADDRNOTAVAIL); 461 462 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle); 463 if (!adapter) 464 return ERR_PTR(-EPROBE_DEFER); 465 466 client = i2c_new_device(adapter, info); 467 if (!client) 468 return ERR_PTR(-ENODEV); 469 470 return client; 471 } 472 EXPORT_SYMBOL_GPL(i2c_acpi_new_device); 473 474 #ifdef CONFIG_ACPI_I2C_OPREGION 475 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, 476 u8 cmd, u8 *data, u8 data_len) 477 { 478 479 struct i2c_msg msgs[2]; 480 int ret; 481 u8 *buffer; 482 483 buffer = kzalloc(data_len, GFP_KERNEL); 484 if (!buffer) 485 return AE_NO_MEMORY; 486 487 msgs[0].addr = client->addr; 488 msgs[0].flags = client->flags; 489 msgs[0].len = 1; 490 msgs[0].buf = &cmd; 491 492 msgs[1].addr = client->addr; 493 msgs[1].flags = client->flags | I2C_M_RD; 494 msgs[1].len = data_len; 495 msgs[1].buf = buffer; 496 497 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 498 if (ret < 0) { 499 /* Getting a NACK is unfortunately normal with some DSTDs */ 500 if (ret == -EREMOTEIO) 501 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", 502 data_len, client->addr, cmd, ret); 503 else 504 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", 505 data_len, client->addr, cmd, ret); 506 /* 2 transfers must have completed successfully */ 507 } else if (ret == 2) { 508 memcpy(data, buffer, data_len); 509 ret = 0; 510 } else { 511 ret = -EIO; 512 } 513 514 kfree(buffer); 515 return ret; 516 } 517 518 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, 519 u8 cmd, u8 *data, u8 data_len) 520 { 521 522 struct i2c_msg msgs[1]; 523 u8 *buffer; 524 int ret = AE_OK; 525 526 buffer = kzalloc(data_len + 1, GFP_KERNEL); 527 if (!buffer) 528 return AE_NO_MEMORY; 529 530 buffer[0] = cmd; 531 memcpy(buffer + 1, data, data_len); 532 533 msgs[0].addr = client->addr; 534 msgs[0].flags = client->flags; 535 msgs[0].len = data_len + 1; 536 msgs[0].buf = buffer; 537 538 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 539 540 kfree(buffer); 541 542 if (ret < 0) { 543 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret); 544 return ret; 545 } 546 547 /* 1 transfer must have completed successfully */ 548 return (ret == 1) ? 0 : -EIO; 549 } 550 551 static acpi_status 552 i2c_acpi_space_handler(u32 function, acpi_physical_address command, 553 u32 bits, u64 *value64, 554 void *handler_context, void *region_context) 555 { 556 struct gsb_buffer *gsb = (struct gsb_buffer *)value64; 557 struct i2c_acpi_handler_data *data = handler_context; 558 struct acpi_connection_info *info = &data->info; 559 struct acpi_resource_i2c_serialbus *sb; 560 struct i2c_adapter *adapter = data->adapter; 561 struct i2c_client *client; 562 struct acpi_resource *ares; 563 u32 accessor_type = function >> 16; 564 u8 action = function & ACPI_IO_MASK; 565 acpi_status ret; 566 int status; 567 568 ret = acpi_buffer_to_resource(info->connection, info->length, &ares); 569 if (ACPI_FAILURE(ret)) 570 return ret; 571 572 client = kzalloc(sizeof(*client), GFP_KERNEL); 573 if (!client) { 574 ret = AE_NO_MEMORY; 575 goto err; 576 } 577 578 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) { 579 ret = AE_BAD_PARAMETER; 580 goto err; 581 } 582 583 client->adapter = adapter; 584 client->addr = sb->slave_address; 585 586 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 587 client->flags |= I2C_CLIENT_TEN; 588 589 switch (accessor_type) { 590 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: 591 if (action == ACPI_READ) { 592 status = i2c_smbus_read_byte(client); 593 if (status >= 0) { 594 gsb->bdata = status; 595 status = 0; 596 } 597 } else { 598 status = i2c_smbus_write_byte(client, gsb->bdata); 599 } 600 break; 601 602 case ACPI_GSB_ACCESS_ATTRIB_BYTE: 603 if (action == ACPI_READ) { 604 status = i2c_smbus_read_byte_data(client, command); 605 if (status >= 0) { 606 gsb->bdata = status; 607 status = 0; 608 } 609 } else { 610 status = i2c_smbus_write_byte_data(client, command, 611 gsb->bdata); 612 } 613 break; 614 615 case ACPI_GSB_ACCESS_ATTRIB_WORD: 616 if (action == ACPI_READ) { 617 status = i2c_smbus_read_word_data(client, command); 618 if (status >= 0) { 619 gsb->wdata = status; 620 status = 0; 621 } 622 } else { 623 status = i2c_smbus_write_word_data(client, command, 624 gsb->wdata); 625 } 626 break; 627 628 case ACPI_GSB_ACCESS_ATTRIB_BLOCK: 629 if (action == ACPI_READ) { 630 status = i2c_smbus_read_block_data(client, command, 631 gsb->data); 632 if (status >= 0) { 633 gsb->len = status; 634 status = 0; 635 } 636 } else { 637 status = i2c_smbus_write_block_data(client, command, 638 gsb->len, gsb->data); 639 } 640 break; 641 642 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: 643 if (action == ACPI_READ) { 644 status = acpi_gsb_i2c_read_bytes(client, command, 645 gsb->data, info->access_length); 646 } else { 647 status = acpi_gsb_i2c_write_bytes(client, command, 648 gsb->data, info->access_length); 649 } 650 break; 651 652 default: 653 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n", 654 accessor_type, client->addr); 655 ret = AE_BAD_PARAMETER; 656 goto err; 657 } 658 659 gsb->status = status; 660 661 err: 662 kfree(client); 663 ACPI_FREE(ares); 664 return ret; 665 } 666 667 668 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) 669 { 670 acpi_handle handle; 671 struct i2c_acpi_handler_data *data; 672 acpi_status status; 673 674 if (!adapter->dev.parent) 675 return -ENODEV; 676 677 handle = ACPI_HANDLE(adapter->dev.parent); 678 679 if (!handle) 680 return -ENODEV; 681 682 data = kzalloc(sizeof(struct i2c_acpi_handler_data), 683 GFP_KERNEL); 684 if (!data) 685 return -ENOMEM; 686 687 data->adapter = adapter; 688 status = acpi_bus_attach_private_data(handle, (void *)data); 689 if (ACPI_FAILURE(status)) { 690 kfree(data); 691 return -ENOMEM; 692 } 693 694 status = acpi_install_address_space_handler(handle, 695 ACPI_ADR_SPACE_GSBUS, 696 &i2c_acpi_space_handler, 697 NULL, 698 data); 699 if (ACPI_FAILURE(status)) { 700 dev_err(&adapter->dev, "Error installing i2c space handler\n"); 701 acpi_bus_detach_private_data(handle); 702 kfree(data); 703 return -ENOMEM; 704 } 705 706 acpi_walk_dep_device_list(handle); 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 */ 735