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.h>
  15 #include <linux/gpio/consumer.h>
  16 #include <linux/gpio/driver.h>
  17 #include <linux/export.h>
  18 #include <linux/acpi.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/mutex.h>
  21 #include <linux/pinctrl/pinctrl.h>
  22
  23 #include "gpiolib.h"
  24
  25 struct acpi_gpio_event {
  26         struct list_head node;
  27         acpi_handle handle;
  28         unsigned int pin;
  29         unsigned int irq;
  30         struct gpio_desc *desc;
  31 };
  32
  33 struct acpi_gpio_connection {
  34         struct list_head node;
  35         unsigned int pin;
  36         struct gpio_desc *desc;
  37 };
  38
  39 struct acpi_gpio_chip {
  40         /*
  41          * ACPICA requires that the first field of the context parameter
  42          * passed to acpi_install_address_space_handler() is large enough
  43          * to hold struct acpi_connection_info.
  44          */
  45         struct acpi_connection_info conn_info;
  46         struct list_head conns;
  47         struct mutex conn_lock;
  48         struct gpio_chip *chip;
  49         struct list_head events;
  50 };
  51
  52 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
  53 {
  54         if (!gc->dev)
  55                 return false;
  56
  57         return ACPI_HANDLE(gc->dev) == data;
  58 }
  59
  60 #ifdef CONFIG_PINCTRL
  61 /**
  62  * acpi_gpiochip_pin_to_gpio_offset() - translates ACPI GPIO to Linux GPIO
  63  * @chip: GPIO chip
  64  * @pin: ACPI GPIO pin number from GpioIo/GpioInt resource
  65  *
  66  * Function takes ACPI GpioIo/GpioInt pin number as a parameter and
  67  * translates it to a corresponding offset suitable to be passed to a
  68  * GPIO controller driver.
  69  *
  70  * Typically the returned offset is same as @pin, but if the GPIO
  71  * controller uses pin controller and the mapping is not contigous the
  72  * offset might be different.
  73  */
  74 static int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip, int pin)
  75 {
  76         struct gpio_pin_range *pin_range;
  77
  78         /* If there are no ranges in this chip, use 1:1 mapping */
  79         if (list_empty(&chip->pin_ranges))
  80                 return pin;
  81
  82         list_for_each_entry(pin_range, &chip->pin_ranges, node) {
  83                 const struct pinctrl_gpio_range *range = &pin_range->range;
  84                 int i;
  85
  86                 if (range->pins) {
  87                         for (i = 0; i < range->npins; i++) {
  88                                 if (range->pins[i] == pin)
  89                                         return range->base + i - chip->base;
  90                         }
  91                 } else {
  92                         if (pin >= range->pin_base &&
  93                             pin < range->pin_base + range->npins) {
  94                                 unsigned gpio_base;
  95
  96                                 gpio_base = range->base - chip->base;
  97                                 return gpio_base + pin - range->pin_base;
  98                         }
  99                 }
 100         }
 101
 102         return -EINVAL;
 103 }
 104 #else
 105 static inline int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip,
 106                                                    int pin)
 107 {
 108         return pin;
 109 }
 110 #endif
 111
 112 /**
 113  * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
 114  * @path:       ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
 115  * @pin:        ACPI GPIO pin number (0-based, controller-relative)
 116  *
 117  * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
 118  * error value
 119  */
 120
 121 static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
 122 {
 123         struct gpio_chip *chip;
 124         acpi_handle handle;
 125         acpi_status status;
 126         int offset;
 127
 128         status = acpi_get_handle(NULL, path, &handle);
 129         if (ACPI_FAILURE(status))
 130                 return ERR_PTR(-ENODEV);
 131
 132         chip = gpiochip_find(handle, acpi_gpiochip_find);
 133         if (!chip)
 134                 return ERR_PTR(-ENODEV);
 135
 136         offset = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 137         if (offset < 0)
 138                 return ERR_PTR(offset);
 139
 140         return gpiochip_get_desc(chip, offset);
 141 }
 142
 143 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
 144 {
 145         struct acpi_gpio_event *event = data;
 146
 147         acpi_evaluate_object(event->handle, NULL, NULL, NULL);
 148
 149         return IRQ_HANDLED;
 150 }
 151
 152 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
 153 {
 154         struct acpi_gpio_event *event = data;
 155
 156         acpi_execute_simple_method(event->handle, NULL, event->pin);
 157
 158         return IRQ_HANDLED;
 159 }
 160
 161 static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
 162 {
 163         /* The address of this function is used as a key. */
 164 }
 165
 166 static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 167                                                    void *context)
 168 {
 169         struct acpi_gpio_chip *acpi_gpio = context;
 170         struct gpio_chip *chip = acpi_gpio->chip;
 171         struct acpi_resource_gpio *agpio;
 172         acpi_handle handle, evt_handle;
 173         struct acpi_gpio_event *event;
 174         irq_handler_t handler = NULL;
 175         struct gpio_desc *desc;
 176         unsigned long irqflags;
 177         int ret, pin, irq;
 178
 179         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 180                 return AE_OK;
 181
 182         agpio = &ares->data.gpio;
 183         if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
 184                 return AE_OK;
 185
 186         handle = ACPI_HANDLE(chip->dev);
 187         pin = agpio->pin_table[0];
 188
 189         if (pin <= 255) {
 190                 char ev_name[5];
 191                 sprintf(ev_name, "_%c%02X",
 192                         agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
 193                         pin);
 194                 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
 195                         handler = acpi_gpio_irq_handler;
 196         }
 197         if (!handler) {
 198                 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
 199                         handler = acpi_gpio_irq_handler_evt;
 200         }
 201         if (!handler)
 202                 return AE_BAD_PARAMETER;
 203
 204         desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
 205         if (IS_ERR(desc)) {
 206                 dev_err(chip->dev, "Failed to request GPIO\n");
 207                 return AE_ERROR;
 208         }
 209
 210         gpiod_direction_input(desc);
 211
 212         ret = gpiochip_lock_as_irq(chip, pin);
 213         if (ret) {
 214                 dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
 215                 goto fail_free_desc;
 216         }
 217
 218         irq = gpiod_to_irq(desc);
 219         if (irq < 0) {
 220                 dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
 221                 goto fail_unlock_irq;
 222         }
 223
 224         irqflags = IRQF_ONESHOT;
 225         if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
 226                 if (agpio->polarity == ACPI_ACTIVE_HIGH)
 227                         irqflags |= IRQF_TRIGGER_HIGH;
 228                 else
 229                         irqflags |= IRQF_TRIGGER_LOW;
 230         } else {
 231                 switch (agpio->polarity) {
 232                 case ACPI_ACTIVE_HIGH:
 233                         irqflags |= IRQF_TRIGGER_RISING;
 234                         break;
 235                 case ACPI_ACTIVE_LOW:
 236                         irqflags |= IRQF_TRIGGER_FALLING;
 237                         break;
 238                 default:
 239                         irqflags |= IRQF_TRIGGER_RISING |
 240                                     IRQF_TRIGGER_FALLING;
 241                         break;
 242                 }
 243         }
 244
 245         event = kzalloc(sizeof(*event), GFP_KERNEL);
 246         if (!event)
 247                 goto fail_unlock_irq;
 248
 249         event->handle = evt_handle;
 250         event->irq = irq;
 251         event->pin = pin;
 252         event->desc = desc;
 253
 254         ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 255                                    "ACPI:Event", event);
 256         if (ret) {
 257                 dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
 258                         event->irq);
 259                 goto fail_free_event;
 260         }
 261
 262         list_add_tail(&event->node, &acpi_gpio->events);
 263         return AE_OK;
 264
 265 fail_free_event:
 266         kfree(event);
 267 fail_unlock_irq:
 268         gpiochip_unlock_as_irq(chip, pin);
 269 fail_free_desc:
 270         gpiochip_free_own_desc(desc);
 271
 272         return AE_ERROR;
 273 }
 274
 275 /**
 276  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
 277  * @chip:      GPIO chip
 278  *
 279  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
 280  * handled by ACPI event methods which need to be called from the GPIO
 281  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
 282  * gpio pins have acpi event methods and assigns interrupt handlers that calls
 283  * the acpi event methods for those pins.
 284  */
 285 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 286 {
 287         struct acpi_gpio_chip *acpi_gpio;
 288         acpi_handle handle;
 289         acpi_status status;
 290
 291         if (!chip->dev || !chip->to_irq)
 292                 return;
 293
 294         handle = ACPI_HANDLE(chip->dev);
 295         if (!handle)
 296                 return;
 297
 298         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 299         if (ACPI_FAILURE(status))
 300                 return;
 301
 302         INIT_LIST_HEAD(&acpi_gpio->events);
 303         acpi_walk_resources(ACPI_HANDLE(chip->dev), "_AEI",
 304                             acpi_gpiochip_request_interrupt, acpi_gpio);
 305 }
 306
 307 /**
 308  * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
 309  * @chip:      GPIO chip
 310  *
 311  * Free interrupts associated with GPIO ACPI event method for the given
 312  * GPIO chip.
 313  */
 314 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 315 {
 316         struct acpi_gpio_chip *acpi_gpio;
 317         struct acpi_gpio_event *event, *ep;
 318         acpi_handle handle;
 319         acpi_status status;
 320
 321         if (!chip->dev || !chip->to_irq)
 322                 return;
 323
 324         handle = ACPI_HANDLE(chip->dev);
 325         if (!handle)
 326                 return;
 327
 328         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 329         if (ACPI_FAILURE(status))
 330                 return;
 331
 332         list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
 333                 struct gpio_desc *desc;
 334
 335                 free_irq(event->irq, event);
 336                 desc = event->desc;
 337                 if (WARN_ON(IS_ERR(desc)))
 338                         continue;
 339                 gpiochip_unlock_as_irq(chip, event->pin);
 340                 gpiochip_free_own_desc(desc);
 341                 list_del(&event->node);
 342                 kfree(event);
 343         }
 344 }
 345
 346 int acpi_dev_add_driver_gpios(struct acpi_device *adev,
 347                               const struct acpi_gpio_mapping *gpios)
 348 {
 349         if (adev && gpios) {
 350                 adev->driver_gpios = gpios;
 351                 return 0;
 352         }
 353         return -EINVAL;
 354 }
 355 EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);
 356
 357 static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
 358                                       const char *name, int index,
 359                                       struct acpi_reference_args *args)
 360 {
 361         const struct acpi_gpio_mapping *gm;
 362
 363         if (!adev->driver_gpios)
 364                 return false;
 365
 366         for (gm = adev->driver_gpios; gm->name; gm++)
 367                 if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
 368                         const struct acpi_gpio_params *par = gm->data + index;
 369
 370                         args->adev = adev;
 371                         args->args[0] = par->crs_entry_index;
 372                         args->args[1] = par->line_index;
 373                         args->args[2] = par->active_low;
 374                         args->nargs = 3;
 375                         return true;
 376                 }
 377
 378         return false;
 379 }
 380
 381 struct acpi_gpio_lookup {
 382         struct acpi_gpio_info info;
 383         int index;
 384         int pin_index;
 385         struct gpio_desc *desc;
 386         int n;
 387 };
 388
 389 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 390 {
 391         struct acpi_gpio_lookup *lookup = data;
 392
 393         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 394                 return 1;
 395
 396         if (lookup->n++ == lookup->index && !lookup->desc) {
 397                 const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 398                 int pin_index = lookup->pin_index;
 399
 400                 if (pin_index >= agpio->pin_table_length)
 401                         return 1;
 402
 403                 lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
 404                                               agpio->pin_table[pin_index]);
 405                 lookup->info.gpioint =
 406                         agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 407
 408                 /*
 409                  * ActiveLow is only specified for GpioInt resource. If
 410                  * GpioIo is used then the only way to set the flag is
 411                  * to use _DSD "gpios" property.
 412                  */
 413                 if (lookup->info.gpioint)
 414                         lookup->info.active_low =
 415                                 agpio->polarity == ACPI_ACTIVE_LOW;
 416         }
 417
 418         return 1;
 419 }
 420
 421 /**
 422  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 423  * @adev: pointer to a ACPI device to get GPIO from
 424  * @propname: Property name of the GPIO (optional)
 425  * @index: index of GpioIo/GpioInt resource (starting from %0)
 426  * @info: info pointer to fill in (optional)
 427  *
 428  * Function goes through ACPI resources for @adev and based on @index looks
 429  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 430  * and returns it. @index matches GpioIo/GpioInt resources only so if there
 431  * are total %3 GPIO resources, the index goes from %0 to %2.
 432  *
 433  * If @propname is specified the GPIO is looked using device property. In
 434  * that case @index is used to select the GPIO entry in the property value
 435  * (in case of multiple).
 436  *
 437  * If the GPIO cannot be translated or there is an error an ERR_PTR is
 438  * returned.
 439  *
 440  * Note: if the GPIO resource has multiple entries in the pin list, this
 441  * function only returns the first.
 442  */
 443 struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 444                                           const char *propname, int index,
 445                                           struct acpi_gpio_info *info)
 446 {
 447         struct acpi_gpio_lookup lookup;
 448         struct list_head resource_list;
 449         bool active_low = false;
 450         int ret;
 451
 452         if (!adev)
 453                 return ERR_PTR(-ENODEV);
 454
 455         memset(&lookup, 0, sizeof(lookup));
 456         lookup.index = index;
 457
 458         if (propname) {
 459                 struct acpi_reference_args args;
 460
 461                 dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
 462
 463                 memset(&args, 0, sizeof(args));
 464                 ret = acpi_dev_get_property_reference(adev, propname,
 465                                                       index, &args);
 466                 if (ret) {
 467                         bool found = acpi_get_driver_gpio_data(adev, propname,
 468                                                                index, &args);
 469                         if (!found)
 470                                 return ERR_PTR(ret);
 471                 }
 472
 473                 /*
 474                  * The property was found and resolved so need to
 475                  * lookup the GPIO based on returned args instead.
 476                  */
 477                 adev = args.adev;
 478                 if (args.nargs >= 2) {
 479                         lookup.index = args.args[0];
 480                         lookup.pin_index = args.args[1];
 481                         /*
 482                          * 3rd argument, if present is used to
 483                          * specify active_low.
 484                          */
 485                         if (args.nargs >= 3)
 486                                 active_low = !!args.args[2];
 487                 }
 488
 489                 dev_dbg(&adev->dev, "GPIO: _DSD returned %s %zd %llu %llu %llu\n",
 490                         dev_name(&adev->dev), args.nargs,
 491                         args.args[0], args.args[1], args.args[2]);
 492         } else {
 493                 dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
 494         }
 495
 496         INIT_LIST_HEAD(&resource_list);
 497         ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 498                                      &lookup);
 499         if (ret < 0)
 500                 return ERR_PTR(ret);
 501
 502         acpi_dev_free_resource_list(&resource_list);
 503
 504         if (lookup.desc && info) {
 505                 *info = lookup.info;
 506                 if (active_low)
 507                         info->active_low = active_low;
 508         }
 509
 510         return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
 511 }
 512
 513 static acpi_status
 514 acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 515                             u32 bits, u64 *value, void *handler_context,
 516                             void *region_context)
 517 {
 518         struct acpi_gpio_chip *achip = region_context;
 519         struct gpio_chip *chip = achip->chip;
 520         struct acpi_resource_gpio *agpio;
 521         struct acpi_resource *ares;
 522         int pin_index = (int)address;
 523         acpi_status status;
 524         bool pull_up;
 525         int length;
 526         int i;
 527
 528         status = acpi_buffer_to_resource(achip->conn_info.connection,
 529                                          achip->conn_info.length, &ares);
 530         if (ACPI_FAILURE(status))
 531                 return status;
 532
 533         if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
 534                 ACPI_FREE(ares);
 535                 return AE_BAD_PARAMETER;
 536         }
 537
 538         agpio = &ares->data.gpio;
 539         pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
 540
 541         if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
 542             function == ACPI_WRITE)) {
 543                 ACPI_FREE(ares);
 544                 return AE_BAD_PARAMETER;
 545         }
 546
 547         length = min(agpio->pin_table_length, (u16)(pin_index + bits));
 548         for (i = pin_index; i < length; ++i) {
 549                 unsigned pin = agpio->pin_table[i];
 550                 struct acpi_gpio_connection *conn;
 551                 struct gpio_desc *desc;
 552                 bool found;
 553
 554                 mutex_lock(&achip->conn_lock);
 555
 556                 found = false;
 557                 list_for_each_entry(conn, &achip->conns, node) {
 558                         if (conn->pin == pin) {
 559                                 found = true;
 560                                 desc = conn->desc;
 561                                 break;
 562                         }
 563                 }
 564                 if (!found) {
 565                         desc = gpiochip_request_own_desc(chip, pin,
 566                                                          "ACPI:OpRegion");
 567                         if (IS_ERR(desc)) {
 568                                 status = AE_ERROR;
 569                                 mutex_unlock(&achip->conn_lock);
 570                                 goto out;
 571                         }
 572
 573                         switch (agpio->io_restriction) {
 574                         case ACPI_IO_RESTRICT_INPUT:
 575                                 gpiod_direction_input(desc);
 576                                 break;
 577                         case ACPI_IO_RESTRICT_OUTPUT:
 578                                 /*
 579                                  * ACPI GPIO resources don't contain an
 580                                  * initial value for the GPIO. Therefore we
 581                                  * deduce that value from the pull field
 582                                  * instead. If the pin is pulled up we
 583                                  * assume default to be high, otherwise
 584                                  * low.
 585                                  */
 586                                 gpiod_direction_output(desc, pull_up);
 587                                 break;
 588                         default:
 589                                 /*
 590                                  * Assume that the BIOS has configured the
 591                                  * direction and pull accordingly.
 592                                  */
 593                                 break;
 594                         }
 595
 596                         conn = kzalloc(sizeof(*conn), GFP_KERNEL);
 597                         if (!conn) {
 598                                 status = AE_NO_MEMORY;
 599                                 gpiochip_free_own_desc(desc);
 600                                 mutex_unlock(&achip->conn_lock);
 601                                 goto out;
 602                         }
 603
 604                         conn->pin = pin;
 605                         conn->desc = desc;
 606                         list_add_tail(&conn->node, &achip->conns);
 607                 }
 608
 609                 mutex_unlock(&achip->conn_lock);
 610
 611                 if (function == ACPI_WRITE)
 612                         gpiod_set_raw_value_cansleep(desc,
 613                                                      !!((1 << i) & *value));
 614                 else
 615                         *value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
 616         }
 617
 618 out:
 619         ACPI_FREE(ares);
 620         return status;
 621 }
 622
 623 static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
 624 {
 625         struct gpio_chip *chip = achip->chip;
 626         acpi_handle handle = ACPI_HANDLE(chip->dev);
 627         acpi_status status;
 628
 629         INIT_LIST_HEAD(&achip->conns);
 630         mutex_init(&achip->conn_lock);
 631         status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 632                                                     acpi_gpio_adr_space_handler,
 633                                                     NULL, achip);
 634         if (ACPI_FAILURE(status))
 635                 dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
 636 }
 637
 638 static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
 639 {
 640         struct gpio_chip *chip = achip->chip;
 641         acpi_handle handle = ACPI_HANDLE(chip->dev);
 642         struct acpi_gpio_connection *conn, *tmp;
 643         acpi_status status;
 644
 645         status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 646                                                    acpi_gpio_adr_space_handler);
 647         if (ACPI_FAILURE(status)) {
 648                 dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
 649                 return;
 650         }
 651
 652         list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
 653                 gpiochip_free_own_desc(conn->desc);
 654                 list_del(&conn->node);
 655                 kfree(conn);
 656         }
 657 }
 658
 659 void acpi_gpiochip_add(struct gpio_chip *chip)
 660 {
 661         struct acpi_gpio_chip *acpi_gpio;
 662         acpi_handle handle;
 663         acpi_status status;
 664
 665         if (!chip || !chip->dev)
 666                 return;
 667
 668         handle = ACPI_HANDLE(chip->dev);
 669         if (!handle)
 670                 return;
 671
 672         acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
 673         if (!acpi_gpio) {
 674                 dev_err(chip->dev,
 675                         "Failed to allocate memory for ACPI GPIO chip\n");
 676                 return;
 677         }
 678
 679         acpi_gpio->chip = chip;
 680
 681         status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
 682         if (ACPI_FAILURE(status)) {
 683                 dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
 684                 kfree(acpi_gpio);
 685                 return;
 686         }
 687
 688         acpi_gpiochip_request_regions(acpi_gpio);
 689 }
 690
 691 void acpi_gpiochip_remove(struct gpio_chip *chip)
 692 {
 693         struct acpi_gpio_chip *acpi_gpio;
 694         acpi_handle handle;
 695         acpi_status status;
 696
 697         if (!chip || !chip->dev)
 698                 return;
 699
 700         handle = ACPI_HANDLE(chip->dev);
 701         if (!handle)
 702                 return;
 703
 704         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 705         if (ACPI_FAILURE(status)) {
 706                 dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
 707                 return;
 708         }
 709
 710         acpi_gpiochip_free_regions(acpi_gpio);
 711
 712         acpi_detach_data(handle, acpi_gpio_chip_dh);
 713         kfree(acpi_gpio);
 714 }