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