drivers/gpio/gpiolib-acpi.c

   1 /*
   2  * ACPI helpers for GPIO API
   3  *
   4  * Copyright (C) 2012, Intel Corporation
   5  * Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
   6  *          Mika Westerberg <mika.westerberg@linux.intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/errno.h>
  14 #include <linux/gpio/consumer.h>
  15 #include <linux/gpio/driver.h>
  16 #include <linux/export.h>
  17 #include <linux/acpi.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/mutex.h>
  20
  21 #include "gpiolib.h"
  22
  23 struct acpi_gpio_event {
  24         struct list_head node;
  25         acpi_handle handle;
  26         unsigned int pin;
  27         unsigned int irq;
  28         struct gpio_desc *desc;
  29 };
  30
  31 struct acpi_gpio_connection {
  32         struct list_head node;
  33         unsigned int pin;
  34         struct gpio_desc *desc;
  35 };
  36
  37 struct acpi_gpio_chip {
  38         /*
  39          * ACPICA requires that the first field of the context parameter
  40          * passed to acpi_install_address_space_handler() is large enough
  41          * to hold struct acpi_connection_info.
  42          */
  43         struct acpi_connection_info conn_info;
  44         struct list_head conns;
  45         struct mutex conn_lock;
  46         struct gpio_chip *chip;
  47         struct list_head events;
  48 };
  49
  50 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
  51 {
  52         if (!gc->dev)
  53                 return false;
  54
  55         return ACPI_HANDLE(gc->dev) == data;
  56 }
  57
  58 /**
  59  * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
  60  * @path:       ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
  61  * @pin:        ACPI GPIO pin number (0-based, controller-relative)
  62  *
  63  * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
  64  * error value
  65  */
  66
  67 static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
  68 {
  69         struct gpio_chip *chip;
  70         acpi_handle handle;
  71         acpi_status status;
  72
  73         status = acpi_get_handle(NULL, path, &handle);
  74         if (ACPI_FAILURE(status))
  75                 return ERR_PTR(-ENODEV);
  76
  77         chip = gpiochip_find(handle, acpi_gpiochip_find);
  78         if (!chip)
  79                 return ERR_PTR(-ENODEV);
  80
  81         if (pin < 0 || pin > chip->ngpio)
  82                 return ERR_PTR(-EINVAL);
  83
  84         return gpiochip_get_desc(chip, pin);
  85 }
  86
  87 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
  88 {
  89         struct acpi_gpio_event *event = data;
  90
  91         acpi_evaluate_object(event->handle, NULL, NULL, NULL);
  92
  93         return IRQ_HANDLED;
  94 }
  95
  96 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
  97 {
  98         struct acpi_gpio_event *event = data;
  99
 100         acpi_execute_simple_method(event->handle, NULL, event->pin);
 101
 102         return IRQ_HANDLED;
 103 }
 104
 105 static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
 106 {
 107         /* The address of this function is used as a key. */
 108 }
 109
 110 static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 111                                                    void *context)
 112 {
 113         struct acpi_gpio_chip *acpi_gpio = context;
 114         struct gpio_chip *chip = acpi_gpio->chip;
 115         struct acpi_resource_gpio *agpio;
 116         acpi_handle handle, evt_handle;
 117         struct acpi_gpio_event *event;
 118         irq_handler_t handler = NULL;
 119         struct gpio_desc *desc;
 120         unsigned long irqflags;
 121         int ret, pin, irq;
 122
 123         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 124                 return AE_OK;
 125
 126         agpio = &ares->data.gpio;
 127         if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
 128                 return AE_OK;
 129
 130         handle = ACPI_HANDLE(chip->dev);
 131         pin = agpio->pin_table[0];
 132
 133         if (pin <= 255) {
 134                 char ev_name[5];
 135                 sprintf(ev_name, "_%c%02X",
 136                         agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
 137                         pin);
 138                 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
 139                         handler = acpi_gpio_irq_handler;
 140         }
 141         if (!handler) {
 142                 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
 143                         handler = acpi_gpio_irq_handler_evt;
 144         }
 145         if (!handler)
 146                 return AE_BAD_PARAMETER;
 147
 148         desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
 149         if (IS_ERR(desc)) {
 150                 dev_err(chip->dev, "Failed to request GPIO\n");
 151                 return AE_ERROR;
 152         }
 153
 154         gpiod_direction_input(desc);
 155
 156         ret = gpiochip_lock_as_irq(chip, pin);
 157         if (ret) {
 158                 dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
 159                 goto fail_free_desc;
 160         }
 161
 162         irq = gpiod_to_irq(desc);
 163         if (irq < 0) {
 164                 dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
 165                 goto fail_unlock_irq;
 166         }
 167
 168         irqflags = IRQF_ONESHOT;
 169         if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
 170                 if (agpio->polarity == ACPI_ACTIVE_HIGH)
 171                         irqflags |= IRQF_TRIGGER_HIGH;
 172                 else
 173                         irqflags |= IRQF_TRIGGER_LOW;
 174         } else {
 175                 switch (agpio->polarity) {
 176                 case ACPI_ACTIVE_HIGH:
 177                         irqflags |= IRQF_TRIGGER_RISING;
 178                         break;
 179                 case ACPI_ACTIVE_LOW:
 180                         irqflags |= IRQF_TRIGGER_FALLING;
 181                         break;
 182                 default:
 183                         irqflags |= IRQF_TRIGGER_RISING |
 184                                     IRQF_TRIGGER_FALLING;
 185                         break;
 186                 }
 187         }
 188
 189         event = kzalloc(sizeof(*event), GFP_KERNEL);
 190         if (!event)
 191                 goto fail_unlock_irq;
 192
 193         event->handle = evt_handle;
 194         event->irq = irq;
 195         event->pin = pin;
 196         event->desc = desc;
 197
 198         ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 199                                    "ACPI:Event", event);
 200         if (ret) {
 201                 dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
 202                         event->irq);
 203                 goto fail_free_event;
 204         }
 205
 206         list_add_tail(&event->node, &acpi_gpio->events);
 207         return AE_OK;
 208
 209 fail_free_event:
 210         kfree(event);
 211 fail_unlock_irq:
 212         gpiochip_unlock_as_irq(chip, pin);
 213 fail_free_desc:
 214         gpiochip_free_own_desc(desc);
 215
 216         return AE_ERROR;
 217 }
 218
 219 /**
 220  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
 221  * @chip:      GPIO chip
 222  *
 223  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
 224  * handled by ACPI event methods which need to be called from the GPIO
 225  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
 226  * gpio pins have acpi event methods and assigns interrupt handlers that calls
 227  * the acpi event methods for those pins.
 228  */
 229 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 230 {
 231         struct acpi_gpio_chip *acpi_gpio;
 232         acpi_handle handle;
 233         acpi_status status;
 234
 235         if (!chip->dev || !chip->to_irq)
 236                 return;
 237
 238         handle = ACPI_HANDLE(chip->dev);
 239         if (!handle)
 240                 return;
 241
 242         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 243         if (ACPI_FAILURE(status))
 244                 return;
 245
 246         INIT_LIST_HEAD(&acpi_gpio->events);
 247         acpi_walk_resources(ACPI_HANDLE(chip->dev), "_AEI",
 248                             acpi_gpiochip_request_interrupt, acpi_gpio);
 249 }
 250
 251 /**
 252  * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
 253  * @chip:      GPIO chip
 254  *
 255  * Free interrupts associated with GPIO ACPI event method for the given
 256  * GPIO chip.
 257  */
 258 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 259 {
 260         struct acpi_gpio_chip *acpi_gpio;
 261         struct acpi_gpio_event *event, *ep;
 262         acpi_handle handle;
 263         acpi_status status;
 264
 265         if (!chip->dev || !chip->to_irq)
 266                 return;
 267
 268         handle = ACPI_HANDLE(chip->dev);
 269         if (!handle)
 270                 return;
 271
 272         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 273         if (ACPI_FAILURE(status))
 274                 return;
 275
 276         list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
 277                 struct gpio_desc *desc;
 278
 279                 free_irq(event->irq, event);
 280                 desc = event->desc;
 281                 if (WARN_ON(IS_ERR(desc)))
 282                         continue;
 283                 gpiochip_unlock_as_irq(chip, event->pin);
 284                 gpiochip_free_own_desc(desc);
 285                 list_del(&event->node);
 286                 kfree(event);
 287         }
 288 }
 289
 290 struct acpi_gpio_lookup {
 291         struct acpi_gpio_info info;
 292         int index;
 293         struct gpio_desc *desc;
 294         int n;
 295 };
 296
 297 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 298 {
 299         struct acpi_gpio_lookup *lookup = data;
 300
 301         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 302                 return 1;
 303
 304         if (lookup->n++ == lookup->index && !lookup->desc) {
 305                 const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 306
 307                 lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
 308                                               agpio->pin_table[0]);
 309                 lookup->info.gpioint =
 310                         agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 311                 lookup->info.active_low =
 312                         agpio->polarity == ACPI_ACTIVE_LOW;
 313         }
 314
 315         return 1;
 316 }
 317
 318 /**
 319  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 320  * @dev: pointer to a device to get GPIO from
 321  * @index: index of GpioIo/GpioInt resource (starting from %0)
 322  * @info: info pointer to fill in (optional)
 323  *
 324  * Function goes through ACPI resources for @dev and based on @index looks
 325  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 326  * and returns it. @index matches GpioIo/GpioInt resources only so if there
 327  * are total %3 GPIO resources, the index goes from %0 to %2.
 328  *
 329  * If the GPIO cannot be translated or there is an error an ERR_PTR is
 330  * returned.
 331  *
 332  * Note: if the GPIO resource has multiple entries in the pin list, this
 333  * function only returns the first.
 334  */
 335 struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
 336                                           struct acpi_gpio_info *info)
 337 {
 338         struct acpi_gpio_lookup lookup;
 339         struct list_head resource_list;
 340         struct acpi_device *adev;
 341         acpi_handle handle;
 342         int ret;
 343
 344         if (!dev)
 345                 return ERR_PTR(-EINVAL);
 346
 347         handle = ACPI_HANDLE(dev);
 348         if (!handle || acpi_bus_get_device(handle, &adev))
 349                 return ERR_PTR(-ENODEV);
 350
 351         memset(&lookup, 0, sizeof(lookup));
 352         lookup.index = index;
 353
 354         INIT_LIST_HEAD(&resource_list);
 355         ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 356                                      &lookup);
 357         if (ret < 0)
 358                 return ERR_PTR(ret);
 359
 360         acpi_dev_free_resource_list(&resource_list);
 361
 362         if (lookup.desc && info)
 363                 *info = lookup.info;
 364
 365         return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
 366 }
 367
 368 static acpi_status
 369 acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 370                             u32 bits, u64 *value, void *handler_context,
 371                             void *region_context)
 372 {
 373         struct acpi_gpio_chip *achip = region_context;
 374         struct gpio_chip *chip = achip->chip;
 375         struct acpi_resource_gpio *agpio;
 376         struct acpi_resource *ares;
 377         int pin_index = (int)address;
 378         acpi_status status;
 379         bool pull_up;
 380         int length;
 381         int i;
 382
 383         status = acpi_buffer_to_resource(achip->conn_info.connection,
 384                                          achip->conn_info.length, &ares);
 385         if (ACPI_FAILURE(status))
 386                 return status;
 387
 388         if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
 389                 ACPI_FREE(ares);
 390                 return AE_BAD_PARAMETER;
 391         }
 392
 393         agpio = &ares->data.gpio;
 394         pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
 395
 396         if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
 397             function == ACPI_WRITE)) {
 398                 ACPI_FREE(ares);
 399                 return AE_BAD_PARAMETER;
 400         }
 401
 402         length = min(agpio->pin_table_length, (u16)(pin_index + bits));
 403         for (i = pin_index; i < length; ++i) {
 404                 unsigned pin = agpio->pin_table[i];
 405                 struct acpi_gpio_connection *conn;
 406                 struct gpio_desc *desc;
 407                 bool found;
 408
 409                 mutex_lock(&achip->conn_lock);
 410
 411                 found = false;
 412                 list_for_each_entry(conn, &achip->conns, node) {
 413                         if (conn->pin == pin) {
 414                                 found = true;
 415                                 desc = conn->desc;
 416                                 break;
 417                         }
 418                 }
 419                 if (!found) {
 420                         desc = gpiochip_request_own_desc(chip, pin,
 421                                                          "ACPI:OpRegion");
 422                         if (IS_ERR(desc)) {
 423                                 status = AE_ERROR;
 424                                 mutex_unlock(&achip->conn_lock);
 425                                 goto out;
 426                         }
 427
 428                         switch (agpio->io_restriction) {
 429                         case ACPI_IO_RESTRICT_INPUT:
 430                                 gpiod_direction_input(desc);
 431                                 break;
 432                         case ACPI_IO_RESTRICT_OUTPUT:
 433                                 /*
 434                                  * ACPI GPIO resources don't contain an
 435                                  * initial value for the GPIO. Therefore we
 436                                  * deduce that value from the pull field
 437                                  * instead. If the pin is pulled up we
 438                                  * assume default to be high, otherwise
 439                                  * low.
 440                                  */
 441                                 gpiod_direction_output(desc, pull_up);
 442                                 break;
 443                         default:
 444                                 /*
 445                                  * Assume that the BIOS has configured the
 446                                  * direction and pull accordingly.
 447                                  */
 448                                 break;
 449                         }
 450
 451                         conn = kzalloc(sizeof(*conn), GFP_KERNEL);
 452                         if (!conn) {
 453                                 status = AE_NO_MEMORY;
 454                                 gpiochip_free_own_desc(desc);
 455                                 mutex_unlock(&achip->conn_lock);
 456                                 goto out;
 457                         }
 458
 459                         conn->pin = pin;
 460                         conn->desc = desc;
 461                         list_add_tail(&conn->node, &achip->conns);
 462                 }
 463
 464                 mutex_unlock(&achip->conn_lock);
 465
 466                 if (function == ACPI_WRITE)
 467                         gpiod_set_raw_value_cansleep(desc,
 468                                                      !!((1 << i) & *value));
 469                 else
 470                         *value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
 471         }
 472
 473 out:
 474         ACPI_FREE(ares);
 475         return status;
 476 }
 477
 478 static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
 479 {
 480         struct gpio_chip *chip = achip->chip;
 481         acpi_handle handle = ACPI_HANDLE(chip->dev);
 482         acpi_status status;
 483
 484         INIT_LIST_HEAD(&achip->conns);
 485         mutex_init(&achip->conn_lock);
 486         status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 487                                                     acpi_gpio_adr_space_handler,
 488                                                     NULL, achip);
 489         if (ACPI_FAILURE(status))
 490                 dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
 491 }
 492
 493 static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
 494 {
 495         struct gpio_chip *chip = achip->chip;
 496         acpi_handle handle = ACPI_HANDLE(chip->dev);
 497         struct acpi_gpio_connection *conn, *tmp;
 498         acpi_status status;
 499
 500         status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 501                                                    acpi_gpio_adr_space_handler);
 502         if (ACPI_FAILURE(status)) {
 503                 dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
 504                 return;
 505         }
 506
 507         list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
 508                 gpiochip_free_own_desc(conn->desc);
 509                 list_del(&conn->node);
 510                 kfree(conn);
 511         }
 512 }
 513
 514 void acpi_gpiochip_add(struct gpio_chip *chip)
 515 {
 516         struct acpi_gpio_chip *acpi_gpio;
 517         acpi_handle handle;
 518         acpi_status status;
 519
 520         if (!chip || !chip->dev)
 521                 return;
 522
 523         handle = ACPI_HANDLE(chip->dev);
 524         if (!handle)
 525                 return;
 526
 527         acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
 528         if (!acpi_gpio) {
 529                 dev_err(chip->dev,
 530                         "Failed to allocate memory for ACPI GPIO chip\n");
 531                 return;
 532         }
 533
 534         acpi_gpio->chip = chip;
 535
 536         status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
 537         if (ACPI_FAILURE(status)) {
 538                 dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
 539                 kfree(acpi_gpio);
 540                 return;
 541         }
 542
 543         acpi_gpiochip_request_regions(acpi_gpio);
 544 }
 545
 546 void acpi_gpiochip_remove(struct gpio_chip *chip)
 547 {
 548         struct acpi_gpio_chip *acpi_gpio;
 549         acpi_handle handle;
 550         acpi_status status;
 551
 552         if (!chip || !chip->dev)
 553                 return;
 554
 555         handle = ACPI_HANDLE(chip->dev);
 556         if (!handle)
 557                 return;
 558
 559         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 560         if (ACPI_FAILURE(status)) {
 561                 dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
 562                 return;
 563         }
 564
 565         acpi_gpiochip_free_regions(acpi_gpio);
 566
 567         acpi_detach_data(handle, acpi_gpio_chip_dh);
 568         kfree(acpi_gpio);
 569 }