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 static int i2c_acpi_find_match_device(struct device *dev, const void *data) 358 { 359 return ACPI_COMPANION(dev) == data; 360 } 361 362 struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle) 363 { 364 struct device *dev; 365 366 dev = bus_find_device(&i2c_bus_type, NULL, handle, 367 i2c_acpi_find_match_adapter); 368 return dev ? i2c_verify_adapter(dev) : NULL; 369 } 370 EXPORT_SYMBOL_GPL(i2c_acpi_find_adapter_by_handle); 371 372 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev) 373 { 374 struct device *dev; 375 376 dev = bus_find_device(&i2c_bus_type, NULL, adev, 377 i2c_acpi_find_match_device); 378 return dev ? i2c_verify_client(dev) : NULL; 379 } 380 381 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value, 382 void *arg) 383 { 384 struct acpi_device *adev = arg; 385 struct i2c_board_info info; 386 acpi_handle adapter_handle; 387 struct i2c_adapter *adapter; 388 struct i2c_client *client; 389 390 switch (value) { 391 case ACPI_RECONFIG_DEVICE_ADD: 392 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle)) 393 break; 394 395 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle); 396 if (!adapter) 397 break; 398 399 i2c_acpi_register_device(adapter, adev, &info); 400 break; 401 case ACPI_RECONFIG_DEVICE_REMOVE: 402 if (!acpi_device_enumerated(adev)) 403 break; 404 405 client = i2c_acpi_find_client_by_adev(adev); 406 if (!client) 407 break; 408 409 i2c_unregister_device(client); 410 put_device(&client->dev); 411 break; 412 } 413 414 return NOTIFY_OK; 415 } 416 417 struct notifier_block i2c_acpi_notifier = { 418 .notifier_call = i2c_acpi_notify, 419 }; 420 421 /** 422 * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource 423 * @dev: Device owning the ACPI resources to get the client from 424 * @index: Index of ACPI resource to get 425 * @info: describes the I2C device; note this is modified (addr gets set) 426 * Context: can sleep 427 * 428 * By default the i2c subsys creates an i2c-client for the first I2cSerialBus 429 * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus 430 * resources, in that case this function can be used to create an i2c-client 431 * for other I2cSerialBus resources in the Current Resource Settings table. 432 * 433 * Also see i2c_new_device, which this function calls to create the i2c-client. 434 * 435 * Returns a pointer to the new i2c-client, or error pointer in case of failure. 436 * Specifically, -EPROBE_DEFER is returned if the adapter is not found. 437 */ 438 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index, 439 struct i2c_board_info *info) 440 { 441 struct i2c_acpi_lookup lookup; 442 struct i2c_adapter *adapter; 443 struct i2c_client *client; 444 struct acpi_device *adev; 445 LIST_HEAD(resource_list); 446 int ret; 447 448 adev = ACPI_COMPANION(dev); 449 if (!adev) 450 return ERR_PTR(-EINVAL); 451 452 memset(&lookup, 0, sizeof(lookup)); 453 lookup.info = info; 454 lookup.device_handle = acpi_device_handle(adev); 455 lookup.index = index; 456 457 ret = acpi_dev_get_resources(adev, &resource_list, 458 i2c_acpi_fill_info, &lookup); 459 if (ret < 0) 460 return ERR_PTR(ret); 461 462 acpi_dev_free_resource_list(&resource_list); 463 464 if (!info->addr) 465 return ERR_PTR(-EADDRNOTAVAIL); 466 467 adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle); 468 if (!adapter) 469 return ERR_PTR(-EPROBE_DEFER); 470 471 client = i2c_new_device(adapter, info); 472 if (!client) 473 return ERR_PTR(-ENODEV); 474 475 return client; 476 } 477 EXPORT_SYMBOL_GPL(i2c_acpi_new_device); 478 479 #ifdef CONFIG_ACPI_I2C_OPREGION 480 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client, 481 u8 cmd, u8 *data, u8 data_len) 482 { 483 484 struct i2c_msg msgs[2]; 485 int ret; 486 u8 *buffer; 487 488 buffer = kzalloc(data_len, GFP_KERNEL); 489 if (!buffer) 490 return AE_NO_MEMORY; 491 492 msgs[0].addr = client->addr; 493 msgs[0].flags = client->flags; 494 msgs[0].len = 1; 495 msgs[0].buf = &cmd; 496 497 msgs[1].addr = client->addr; 498 msgs[1].flags = client->flags | I2C_M_RD; 499 msgs[1].len = data_len; 500 msgs[1].buf = buffer; 501 502 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 503 if (ret < 0) { 504 /* Getting a NACK is unfortunately normal with some DSTDs */ 505 if (ret == -EREMOTEIO) 506 dev_dbg(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", 507 data_len, client->addr, cmd, ret); 508 else 509 dev_err(&client->adapter->dev, "i2c read %d bytes from client@%#x starting at reg %#x failed, error: %d\n", 510 data_len, client->addr, cmd, ret); 511 /* 2 transfers must have completed successfully */ 512 } else if (ret == 2) { 513 memcpy(data, buffer, data_len); 514 ret = 0; 515 } else { 516 ret = -EIO; 517 } 518 519 kfree(buffer); 520 return ret; 521 } 522 523 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client, 524 u8 cmd, u8 *data, u8 data_len) 525 { 526 527 struct i2c_msg msgs[1]; 528 u8 *buffer; 529 int ret = AE_OK; 530 531 buffer = kzalloc(data_len + 1, GFP_KERNEL); 532 if (!buffer) 533 return AE_NO_MEMORY; 534 535 buffer[0] = cmd; 536 memcpy(buffer + 1, data, data_len); 537 538 msgs[0].addr = client->addr; 539 msgs[0].flags = client->flags; 540 msgs[0].len = data_len + 1; 541 msgs[0].buf = buffer; 542 543 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs)); 544 545 kfree(buffer); 546 547 if (ret < 0) { 548 dev_err(&client->adapter->dev, "i2c write failed: %d\n", ret); 549 return ret; 550 } 551 552 /* 1 transfer must have completed successfully */ 553 return (ret == 1) ? 0 : -EIO; 554 } 555 556 static acpi_status 557 i2c_acpi_space_handler(u32 function, acpi_physical_address command, 558 u32 bits, u64 *value64, 559 void *handler_context, void *region_context) 560 { 561 struct gsb_buffer *gsb = (struct gsb_buffer *)value64; 562 struct i2c_acpi_handler_data *data = handler_context; 563 struct acpi_connection_info *info = &data->info; 564 struct acpi_resource_i2c_serialbus *sb; 565 struct i2c_adapter *adapter = data->adapter; 566 struct i2c_client *client; 567 struct acpi_resource *ares; 568 u32 accessor_type = function >> 16; 569 u8 action = function & ACPI_IO_MASK; 570 acpi_status ret; 571 int status; 572 573 ret = acpi_buffer_to_resource(info->connection, info->length, &ares); 574 if (ACPI_FAILURE(ret)) 575 return ret; 576 577 client = kzalloc(sizeof(*client), GFP_KERNEL); 578 if (!client) { 579 ret = AE_NO_MEMORY; 580 goto err; 581 } 582 583 if (!value64 || !i2c_acpi_get_i2c_resource(ares, &sb)) { 584 ret = AE_BAD_PARAMETER; 585 goto err; 586 } 587 588 client->adapter = adapter; 589 client->addr = sb->slave_address; 590 591 if (sb->access_mode == ACPI_I2C_10BIT_MODE) 592 client->flags |= I2C_CLIENT_TEN; 593 594 switch (accessor_type) { 595 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV: 596 if (action == ACPI_READ) { 597 status = i2c_smbus_read_byte(client); 598 if (status >= 0) { 599 gsb->bdata = status; 600 status = 0; 601 } 602 } else { 603 status = i2c_smbus_write_byte(client, gsb->bdata); 604 } 605 break; 606 607 case ACPI_GSB_ACCESS_ATTRIB_BYTE: 608 if (action == ACPI_READ) { 609 status = i2c_smbus_read_byte_data(client, command); 610 if (status >= 0) { 611 gsb->bdata = status; 612 status = 0; 613 } 614 } else { 615 status = i2c_smbus_write_byte_data(client, command, 616 gsb->bdata); 617 } 618 break; 619 620 case ACPI_GSB_ACCESS_ATTRIB_WORD: 621 if (action == ACPI_READ) { 622 status = i2c_smbus_read_word_data(client, command); 623 if (status >= 0) { 624 gsb->wdata = status; 625 status = 0; 626 } 627 } else { 628 status = i2c_smbus_write_word_data(client, command, 629 gsb->wdata); 630 } 631 break; 632 633 case ACPI_GSB_ACCESS_ATTRIB_BLOCK: 634 if (action == ACPI_READ) { 635 status = i2c_smbus_read_block_data(client, command, 636 gsb->data); 637 if (status >= 0) { 638 gsb->len = status; 639 status = 0; 640 } 641 } else { 642 status = i2c_smbus_write_block_data(client, command, 643 gsb->len, gsb->data); 644 } 645 break; 646 647 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE: 648 if (action == ACPI_READ) { 649 status = acpi_gsb_i2c_read_bytes(client, command, 650 gsb->data, info->access_length); 651 } else { 652 status = acpi_gsb_i2c_write_bytes(client, command, 653 gsb->data, info->access_length); 654 } 655 break; 656 657 default: 658 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n", 659 accessor_type, client->addr); 660 ret = AE_BAD_PARAMETER; 661 goto err; 662 } 663 664 gsb->status = status; 665 666 err: 667 kfree(client); 668 ACPI_FREE(ares); 669 return ret; 670 } 671 672 673 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) 674 { 675 acpi_handle handle; 676 struct i2c_acpi_handler_data *data; 677 acpi_status status; 678 679 if (!adapter->dev.parent) 680 return -ENODEV; 681 682 handle = ACPI_HANDLE(adapter->dev.parent); 683 684 if (!handle) 685 return -ENODEV; 686 687 data = kzalloc(sizeof(struct i2c_acpi_handler_data), 688 GFP_KERNEL); 689 if (!data) 690 return -ENOMEM; 691 692 data->adapter = adapter; 693 status = acpi_bus_attach_private_data(handle, (void *)data); 694 if (ACPI_FAILURE(status)) { 695 kfree(data); 696 return -ENOMEM; 697 } 698 699 status = acpi_install_address_space_handler(handle, 700 ACPI_ADR_SPACE_GSBUS, 701 &i2c_acpi_space_handler, 702 NULL, 703 data); 704 if (ACPI_FAILURE(status)) { 705 dev_err(&adapter->dev, "Error installing i2c space handler\n"); 706 acpi_bus_detach_private_data(handle); 707 kfree(data); 708 return -ENOMEM; 709 } 710 711 acpi_walk_dep_device_list(handle); 712 return 0; 713 } 714 715 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) 716 { 717 acpi_handle handle; 718 struct i2c_acpi_handler_data *data; 719 acpi_status status; 720 721 if (!adapter->dev.parent) 722 return; 723 724 handle = ACPI_HANDLE(adapter->dev.parent); 725 726 if (!handle) 727 return; 728 729 acpi_remove_address_space_handler(handle, 730 ACPI_ADR_SPACE_GSBUS, 731 &i2c_acpi_space_handler); 732 733 status = acpi_bus_get_private_data(handle, (void **)&data); 734 if (ACPI_SUCCESS(status)) 735 kfree(data); 736 737 acpi_bus_detach_private_data(handle); 738 } 739 #endif /* CONFIG_ACPI_I2C_OPREGION */ 740