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 static acpi_status i2c_acpi_lookup_speed(acpi_handle handle, u32 level,
 234                                            void *data, void **return_value)
 235 {
 236         struct i2c_acpi_lookup *lookup = data;
 237         struct acpi_device *adev;
 238
 239         if (acpi_bus_get_device(handle, &adev))
 240                 return AE_OK;
 241
 242         if (i2c_acpi_do_lookup(adev, lookup))
 243                 return AE_OK;
 244
 245         if (lookup->search_handle != lookup->adapter_handle)
 246                 return AE_OK;
 247
 248         if (lookup->speed <= lookup->min_speed)
 249                 lookup->min_speed = lookup->speed;
 250
 251         return AE_OK;
 252 }
 253
 254 /**
 255  * i2c_acpi_find_bus_speed - find I2C bus speed from ACPI
 256  * @dev: The device owning the bus
 257  *
 258  * Find the I2C bus speed by walking the ACPI namespace for all I2C slaves
 259  * devices connected to this bus and use the speed of slowest device.
 260  *
 261  * Returns the speed in Hz or zero
 262  */
 263 u32 i2c_acpi_find_bus_speed(struct device *dev)
 264 {
 265         struct i2c_acpi_lookup lookup;
 266         struct i2c_board_info dummy;
 267         acpi_status status;
 268
 269         if (!has_acpi_companion(dev))
 270                 return 0;
 271
 272         memset(&lookup, 0, sizeof(lookup));
 273         lookup.search_handle = ACPI_HANDLE(dev);
 274         lookup.min_speed = UINT_MAX;
 275         lookup.info = &dummy;
 276         lookup.index = -1;
 277
 278         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 279                                      I2C_ACPI_MAX_SCAN_DEPTH,
 280                                      i2c_acpi_lookup_speed, NULL,
 281                                      &lookup, NULL);
 282
 283         if (ACPI_FAILURE(status)) {
 284                 dev_warn(dev, "unable to find I2C bus speed from ACPI\n");
 285                 return 0;
 286         }
 287
 288         return lookup.min_speed != UINT_MAX ? lookup.min_speed : 0;
 289 }
 290 EXPORT_SYMBOL_GPL(i2c_acpi_find_bus_speed);
 291
 292 static int i2c_acpi_match_adapter(struct device *dev, void *data)
 293 {
 294         struct i2c_adapter *adapter = i2c_verify_adapter(dev);
 295
 296         if (!adapter)
 297                 return 0;
 298
 299         return ACPI_HANDLE(dev) == (acpi_handle)data;
 300 }
 301
 302 static int i2c_acpi_match_device(struct device *dev, void *data)
 303 {
 304         return ACPI_COMPANION(dev) == data;
 305 }
 306
 307 static struct i2c_adapter *i2c_acpi_find_adapter_by_handle(acpi_handle handle)
 308 {
 309         struct device *dev;
 310
 311         dev = bus_find_device(&i2c_bus_type, NULL, handle,
 312                               i2c_acpi_match_adapter);
 313         return dev ? i2c_verify_adapter(dev) : NULL;
 314 }
 315
 316 static struct i2c_client *i2c_acpi_find_client_by_adev(struct acpi_device *adev)
 317 {
 318         struct device *dev;
 319
 320         dev = bus_find_device(&i2c_bus_type, NULL, adev, i2c_acpi_match_device);
 321         return dev ? i2c_verify_client(dev) : NULL;
 322 }
 323
 324 static int i2c_acpi_notify(struct notifier_block *nb, unsigned long value,
 325                            void *arg)
 326 {
 327         struct acpi_device *adev = arg;
 328         struct i2c_board_info info;
 329         acpi_handle adapter_handle;
 330         struct i2c_adapter *adapter;
 331         struct i2c_client *client;
 332
 333         switch (value) {
 334         case ACPI_RECONFIG_DEVICE_ADD:
 335                 if (i2c_acpi_get_info(adev, &info, NULL, &adapter_handle))
 336                         break;
 337
 338                 adapter = i2c_acpi_find_adapter_by_handle(adapter_handle);
 339                 if (!adapter)
 340                         break;
 341
 342                 i2c_acpi_register_device(adapter, adev, &info);
 343                 break;
 344         case ACPI_RECONFIG_DEVICE_REMOVE:
 345                 if (!acpi_device_enumerated(adev))
 346                         break;
 347
 348                 client = i2c_acpi_find_client_by_adev(adev);
 349                 if (!client)
 350                         break;
 351
 352                 i2c_unregister_device(client);
 353                 put_device(&client->dev);
 354                 break;
 355         }
 356
 357         return NOTIFY_OK;
 358 }
 359
 360 struct notifier_block i2c_acpi_notifier = {
 361         .notifier_call = i2c_acpi_notify,
 362 };
 363
 364 /**
 365  * i2c_acpi_new_device - Create i2c-client for the Nth I2cSerialBus resource
 366  * @dev:     Device owning the ACPI resources to get the client from
 367  * @index:   Index of ACPI resource to get
 368  * @info:    describes the I2C device; note this is modified (addr gets set)
 369  * Context: can sleep
 370  *
 371  * By default the i2c subsys creates an i2c-client for the first I2cSerialBus
 372  * resource of an acpi_device, but some acpi_devices have multiple I2cSerialBus
 373  * resources, in that case this function can be used to create an i2c-client
 374  * for other I2cSerialBus resources in the Current Resource Settings table.
 375  *
 376  * Also see i2c_new_device, which this function calls to create the i2c-client.
 377  *
 378  * Returns a pointer to the new i2c-client, or NULL if the adapter is not found.
 379  */
 380 struct i2c_client *i2c_acpi_new_device(struct device *dev, int index,
 381                                        struct i2c_board_info *info)
 382 {
 383         struct i2c_acpi_lookup lookup;
 384         struct i2c_adapter *adapter;
 385         struct acpi_device *adev;
 386         LIST_HEAD(resource_list);
 387         int ret;
 388
 389         adev = ACPI_COMPANION(dev);
 390         if (!adev)
 391                 return NULL;
 392
 393         memset(&lookup, 0, sizeof(lookup));
 394         lookup.info = info;
 395         lookup.device_handle = acpi_device_handle(adev);
 396         lookup.index = index;
 397
 398         ret = acpi_dev_get_resources(adev, &resource_list,
 399                                      i2c_acpi_fill_info, &lookup);
 400         acpi_dev_free_resource_list(&resource_list);
 401
 402         if (ret < 0 || !info->addr)
 403                 return NULL;
 404
 405         adapter = i2c_acpi_find_adapter_by_handle(lookup.adapter_handle);
 406         if (!adapter)
 407                 return NULL;
 408
 409         return i2c_new_device(adapter, info);
 410 }
 411 EXPORT_SYMBOL_GPL(i2c_acpi_new_device);
 412
 413 #ifdef CONFIG_ACPI_I2C_OPREGION
 414 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 415                 u8 cmd, u8 *data, u8 data_len)
 416 {
 417
 418         struct i2c_msg msgs[2];
 419         int ret;
 420         u8 *buffer;
 421
 422         buffer = kzalloc(data_len, GFP_KERNEL);
 423         if (!buffer)
 424                 return AE_NO_MEMORY;
 425
 426         msgs[0].addr = client->addr;
 427         msgs[0].flags = client->flags;
 428         msgs[0].len = 1;
 429         msgs[0].buf = &cmd;
 430
 431         msgs[1].addr = client->addr;
 432         msgs[1].flags = client->flags | I2C_M_RD;
 433         msgs[1].len = data_len;
 434         msgs[1].buf = buffer;
 435
 436         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 437         if (ret < 0)
 438                 dev_err(&client->adapter->dev, "i2c read failed\n");
 439         else
 440                 memcpy(data, buffer, data_len);
 441
 442         kfree(buffer);
 443         return ret;
 444 }
 445
 446 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
 447                 u8 cmd, u8 *data, u8 data_len)
 448 {
 449
 450         struct i2c_msg msgs[1];
 451         u8 *buffer;
 452         int ret = AE_OK;
 453
 454         buffer = kzalloc(data_len + 1, GFP_KERNEL);
 455         if (!buffer)
 456                 return AE_NO_MEMORY;
 457
 458         buffer[0] = cmd;
 459         memcpy(buffer + 1, data, data_len);
 460
 461         msgs[0].addr = client->addr;
 462         msgs[0].flags = client->flags;
 463         msgs[0].len = data_len + 1;
 464         msgs[0].buf = buffer;
 465
 466         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 467         if (ret < 0)
 468                 dev_err(&client->adapter->dev, "i2c write failed\n");
 469
 470         kfree(buffer);
 471         return ret;
 472 }
 473
 474 static acpi_status
 475 i2c_acpi_space_handler(u32 function, acpi_physical_address command,
 476                         u32 bits, u64 *value64,
 477                         void *handler_context, void *region_context)
 478 {
 479         struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
 480         struct i2c_acpi_handler_data *data = handler_context;
 481         struct acpi_connection_info *info = &data->info;
 482         struct acpi_resource_i2c_serialbus *sb;
 483         struct i2c_adapter *adapter = data->adapter;
 484         struct i2c_client *client;
 485         struct acpi_resource *ares;
 486         u32 accessor_type = function >> 16;
 487         u8 action = function & ACPI_IO_MASK;
 488         acpi_status ret;
 489         int status;
 490
 491         ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
 492         if (ACPI_FAILURE(ret))
 493                 return ret;
 494
 495         client = kzalloc(sizeof(*client), GFP_KERNEL);
 496         if (!client) {
 497                 ret = AE_NO_MEMORY;
 498                 goto err;
 499         }
 500
 501         if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
 502                 ret = AE_BAD_PARAMETER;
 503                 goto err;
 504         }
 505
 506         sb = &ares->data.i2c_serial_bus;
 507         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
 508                 ret = AE_BAD_PARAMETER;
 509                 goto err;
 510         }
 511
 512         client->adapter = adapter;
 513         client->addr = sb->slave_address;
 514
 515         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
 516                 client->flags |= I2C_CLIENT_TEN;
 517
 518         switch (accessor_type) {
 519         case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
 520                 if (action == ACPI_READ) {
 521                         status = i2c_smbus_read_byte(client);
 522                         if (status >= 0) {
 523                                 gsb->bdata = status;
 524                                 status = 0;
 525                         }
 526                 } else {
 527                         status = i2c_smbus_write_byte(client, gsb->bdata);
 528                 }
 529                 break;
 530
 531         case ACPI_GSB_ACCESS_ATTRIB_BYTE:
 532                 if (action == ACPI_READ) {
 533                         status = i2c_smbus_read_byte_data(client, command);
 534                         if (status >= 0) {
 535                                 gsb->bdata = status;
 536                                 status = 0;
 537                         }
 538                 } else {
 539                         status = i2c_smbus_write_byte_data(client, command,
 540                                         gsb->bdata);
 541                 }
 542                 break;
 543
 544         case ACPI_GSB_ACCESS_ATTRIB_WORD:
 545                 if (action == ACPI_READ) {
 546                         status = i2c_smbus_read_word_data(client, command);
 547                         if (status >= 0) {
 548                                 gsb->wdata = status;
 549                                 status = 0;
 550                         }
 551                 } else {
 552                         status = i2c_smbus_write_word_data(client, command,
 553                                         gsb->wdata);
 554                 }
 555                 break;
 556
 557         case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
 558                 if (action == ACPI_READ) {
 559                         status = i2c_smbus_read_block_data(client, command,
 560                                         gsb->data);
 561                         if (status >= 0) {
 562                                 gsb->len = status;
 563                                 status = 0;
 564                         }
 565                 } else {
 566                         status = i2c_smbus_write_block_data(client, command,
 567                                         gsb->len, gsb->data);
 568                 }
 569                 break;
 570
 571         case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
 572                 if (action == ACPI_READ) {
 573                         status = acpi_gsb_i2c_read_bytes(client, command,
 574                                         gsb->data, info->access_length);
 575                         if (status > 0)
 576                                 status = 0;
 577                 } else {
 578                         status = acpi_gsb_i2c_write_bytes(client, command,
 579                                         gsb->data, info->access_length);
 580                 }
 581                 break;
 582
 583         default:
 584                 dev_warn(&adapter->dev, "protocol 0x%02x not supported for client 0x%02x\n",
 585                          accessor_type, client->addr);
 586                 ret = AE_BAD_PARAMETER;
 587                 goto err;
 588         }
 589
 590         gsb->status = status;
 591
 592  err:
 593         kfree(client);
 594         ACPI_FREE(ares);
 595         return ret;
 596 }
 597
 598
 599 int i2c_acpi_install_space_handler(struct i2c_adapter *adapter)
 600 {
 601         acpi_handle handle;
 602         struct i2c_acpi_handler_data *data;
 603         acpi_status status;
 604
 605         if (!adapter->dev.parent)
 606                 return -ENODEV;
 607
 608         handle = ACPI_HANDLE(adapter->dev.parent);
 609
 610         if (!handle)
 611                 return -ENODEV;
 612
 613         data = kzalloc(sizeof(struct i2c_acpi_handler_data),
 614                             GFP_KERNEL);
 615         if (!data)
 616                 return -ENOMEM;
 617
 618         data->adapter = adapter;
 619         status = acpi_bus_attach_private_data(handle, (void *)data);
 620         if (ACPI_FAILURE(status)) {
 621                 kfree(data);
 622                 return -ENOMEM;
 623         }
 624
 625         status = acpi_install_address_space_handler(handle,
 626                                 ACPI_ADR_SPACE_GSBUS,
 627                                 &i2c_acpi_space_handler,
 628                                 NULL,
 629                                 data);
 630         if (ACPI_FAILURE(status)) {
 631                 dev_err(&adapter->dev, "Error installing i2c space handler\n");
 632                 acpi_bus_detach_private_data(handle);
 633                 kfree(data);
 634                 return -ENOMEM;
 635         }
 636
 637         acpi_walk_dep_device_list(handle);
 638         return 0;
 639 }
 640
 641 void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter)
 642 {
 643         acpi_handle handle;
 644         struct i2c_acpi_handler_data *data;
 645         acpi_status status;
 646
 647         if (!adapter->dev.parent)
 648                 return;
 649
 650         handle = ACPI_HANDLE(adapter->dev.parent);
 651
 652         if (!handle)
 653                 return;
 654
 655         acpi_remove_address_space_handler(handle,
 656                                 ACPI_ADR_SPACE_GSBUS,
 657                                 &i2c_acpi_space_handler);
 658
 659         status = acpi_bus_get_private_data(handle, (void **)&data);
 660         if (ACPI_SUCCESS(status))
 661                 kfree(data);
 662
 663         acpi_bus_detach_private_data(handle);
 664 }
 665 #endif /* CONFIG_ACPI_I2C_OPREGION */