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         pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 205         if (pin < 0)
 206                 return AE_BAD_PARAMETER;
 207
 208         desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
 209         if (IS_ERR(desc)) {
 210                 dev_err(chip->dev, "Failed to request GPIO\n");
 211                 return AE_ERROR;
 212         }
 213
 214         gpiod_direction_input(desc);
 215
 216         ret = gpiochip_lock_as_irq(chip, pin);
 217         if (ret) {
 218                 dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
 219                 goto fail_free_desc;
 220         }
 221
 222         irq = gpiod_to_irq(desc);
 223         if (irq < 0) {
 224                 dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
 225                 goto fail_unlock_irq;
 226         }
 227
 228         irqflags = IRQF_ONESHOT;
 229         if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
 230                 if (agpio->polarity == ACPI_ACTIVE_HIGH)
 231                         irqflags |= IRQF_TRIGGER_HIGH;
 232                 else
 233                         irqflags |= IRQF_TRIGGER_LOW;
 234         } else {
 235                 switch (agpio->polarity) {
 236                 case ACPI_ACTIVE_HIGH:
 237                         irqflags |= IRQF_TRIGGER_RISING;
 238                         break;
 239                 case ACPI_ACTIVE_LOW:
 240                         irqflags |= IRQF_TRIGGER_FALLING;
 241                         break;
 242                 default:
 243                         irqflags |= IRQF_TRIGGER_RISING |
 244                                     IRQF_TRIGGER_FALLING;
 245                         break;
 246                 }
 247         }
 248
 249         event = kzalloc(sizeof(*event), GFP_KERNEL);
 250         if (!event)
 251                 goto fail_unlock_irq;
 252
 253         event->handle = evt_handle;
 254         event->irq = irq;
 255         event->pin = pin;
 256         event->desc = desc;
 257
 258         ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 259                                    "ACPI:Event", event);
 260         if (ret) {
 261                 dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
 262                         event->irq);
 263                 goto fail_free_event;
 264         }
 265
 266         list_add_tail(&event->node, &acpi_gpio->events);
 267         return AE_OK;
 268
 269 fail_free_event:
 270         kfree(event);
 271 fail_unlock_irq:
 272         gpiochip_unlock_as_irq(chip, pin);
 273 fail_free_desc:
 274         gpiochip_free_own_desc(desc);
 275
 276         return AE_ERROR;
 277 }
 278
 279 /**
 280  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
 281  * @chip:      GPIO chip
 282  *
 283  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
 284  * handled by ACPI event methods which need to be called from the GPIO
 285  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
 286  * gpio pins have acpi event methods and assigns interrupt handlers that calls
 287  * the acpi event methods for those pins.
 288  */
 289 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 290 {
 291         struct acpi_gpio_chip *acpi_gpio;
 292         acpi_handle handle;
 293         acpi_status status;
 294
 295         if (!chip->dev || !chip->to_irq)
 296                 return;
 297
 298         handle = ACPI_HANDLE(chip->dev);
 299         if (!handle)
 300                 return;
 301
 302         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 303         if (ACPI_FAILURE(status))
 304                 return;
 305
 306         INIT_LIST_HEAD(&acpi_gpio->events);
 307         acpi_walk_resources(handle, "_AEI",
 308                             acpi_gpiochip_request_interrupt, acpi_gpio);
 309 }
 310
 311 /**
 312  * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
 313  * @chip:      GPIO chip
 314  *
 315  * Free interrupts associated with GPIO ACPI event method for the given
 316  * GPIO chip.
 317  */
 318 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 319 {
 320         struct acpi_gpio_chip *acpi_gpio;
 321         struct acpi_gpio_event *event, *ep;
 322         acpi_handle handle;
 323         acpi_status status;
 324
 325         if (!chip->dev || !chip->to_irq)
 326                 return;
 327
 328         handle = ACPI_HANDLE(chip->dev);
 329         if (!handle)
 330                 return;
 331
 332         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 333         if (ACPI_FAILURE(status))
 334                 return;
 335
 336         list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
 337                 struct gpio_desc *desc;
 338
 339                 free_irq(event->irq, event);
 340                 desc = event->desc;
 341                 if (WARN_ON(IS_ERR(desc)))
 342                         continue;
 343                 gpiochip_unlock_as_irq(chip, event->pin);
 344                 gpiochip_free_own_desc(desc);
 345                 list_del(&event->node);
 346                 kfree(event);
 347         }
 348 }
 349
 350 int acpi_dev_add_driver_gpios(struct acpi_device *adev,
 351                               const struct acpi_gpio_mapping *gpios)
 352 {
 353         if (adev && gpios) {
 354                 adev->driver_gpios = gpios;
 355                 return 0;
 356         }
 357         return -EINVAL;
 358 }
 359 EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);
 360
 361 static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
 362                                       const char *name, int index,
 363                                       struct acpi_reference_args *args)
 364 {
 365         const struct acpi_gpio_mapping *gm;
 366
 367         if (!adev->driver_gpios)
 368                 return false;
 369
 370         for (gm = adev->driver_gpios; gm->name; gm++)
 371                 if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
 372                         const struct acpi_gpio_params *par = gm->data + index;
 373
 374                         args->adev = adev;
 375                         args->args[0] = par->crs_entry_index;
 376                         args->args[1] = par->line_index;
 377                         args->args[2] = par->active_low;
 378                         args->nargs = 3;
 379                         return true;
 380                 }
 381
 382         return false;
 383 }
 384
 385 struct acpi_gpio_lookup {
 386         struct acpi_gpio_info info;
 387         int index;
 388         int pin_index;
 389         struct gpio_desc *desc;
 390         int n;
 391 };
 392
 393 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 394 {
 395         struct acpi_gpio_lookup *lookup = data;
 396
 397         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 398                 return 1;
 399
 400         if (lookup->n++ == lookup->index && !lookup->desc) {
 401                 const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 402                 int pin_index = lookup->pin_index;
 403
 404                 if (pin_index >= agpio->pin_table_length)
 405                         return 1;
 406
 407                 lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
 408                                               agpio->pin_table[pin_index]);
 409                 lookup->info.gpioint =
 410                         agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 411
 412                 /*
 413                  * ActiveLow is only specified for GpioInt resource. If
 414                  * GpioIo is used then the only way to set the flag is
 415                  * to use _DSD "gpios" property.
 416                  */
 417                 if (lookup->info.gpioint)
 418                         lookup->info.active_low =
 419                                 agpio->polarity == ACPI_ACTIVE_LOW;
 420         }
 421
 422         return 1;
 423 }
 424
 425 /**
 426  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 427  * @adev: pointer to a ACPI device to get GPIO from
 428  * @propname: Property name of the GPIO (optional)
 429  * @index: index of GpioIo/GpioInt resource (starting from %0)
 430  * @info: info pointer to fill in (optional)
 431  *
 432  * Function goes through ACPI resources for @adev and based on @index looks
 433  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 434  * and returns it. @index matches GpioIo/GpioInt resources only so if there
 435  * are total %3 GPIO resources, the index goes from %0 to %2.
 436  *
 437  * If @propname is specified the GPIO is looked using device property. In
 438  * that case @index is used to select the GPIO entry in the property value
 439  * (in case of multiple).
 440  *
 441  * If the GPIO cannot be translated or there is an error an ERR_PTR is
 442  * returned.
 443  *
 444  * Note: if the GPIO resource has multiple entries in the pin list, this
 445  * function only returns the first.
 446  */
 447 struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 448                                           const char *propname, int index,
 449                                           struct acpi_gpio_info *info)
 450 {
 451         struct acpi_gpio_lookup lookup;
 452         struct list_head resource_list;
 453         bool active_low = false;
 454         int ret;
 455
 456         if (!adev)
 457                 return ERR_PTR(-ENODEV);
 458
 459         memset(&lookup, 0, sizeof(lookup));
 460         lookup.index = index;
 461
 462         if (propname) {
 463                 struct acpi_reference_args args;
 464
 465                 dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
 466
 467                 memset(&args, 0, sizeof(args));
 468                 ret = acpi_dev_get_property_reference(adev, propname,
 469                                                       index, &args);
 470                 if (ret) {
 471                         bool found = acpi_get_driver_gpio_data(adev, propname,
 472                                                                index, &args);
 473                         if (!found)
 474                                 return ERR_PTR(ret);
 475                 }
 476
 477                 /*
 478                  * The property was found and resolved so need to
 479                  * lookup the GPIO based on returned args instead.
 480                  */
 481                 adev = args.adev;
 482                 if (args.nargs >= 2) {
 483                         lookup.index = args.args[0];
 484                         lookup.pin_index = args.args[1];
 485                         /*
 486                          * 3rd argument, if present is used to
 487                          * specify active_low.
 488                          */
 489                         if (args.nargs >= 3)
 490                                 active_low = !!args.args[2];
 491                 }
 492
 493                 dev_dbg(&adev->dev, "GPIO: _DSD returned %s %zd %llu %llu %llu\n",
 494                         dev_name(&adev->dev), args.nargs,
 495                         args.args[0], args.args[1], args.args[2]);
 496         } else {
 497                 dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
 498         }
 499
 500         INIT_LIST_HEAD(&resource_list);
 501         ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 502                                      &lookup);
 503         if (ret < 0)
 504                 return ERR_PTR(ret);
 505
 506         acpi_dev_free_resource_list(&resource_list);
 507
 508         if (lookup.desc && info) {
 509                 *info = lookup.info;
 510                 if (active_low)
 511                         info->active_low = active_low;
 512         }
 513
 514         return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
 515 }
 516
 517 static acpi_status
 518 acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 519                             u32 bits, u64 *value, void *handler_context,
 520                             void *region_context)
 521 {
 522         struct acpi_gpio_chip *achip = region_context;
 523         struct gpio_chip *chip = achip->chip;
 524         struct acpi_resource_gpio *agpio;
 525         struct acpi_resource *ares;
 526         int pin_index = (int)address;
 527         acpi_status status;
 528         bool pull_up;
 529         int length;
 530         int i;
 531
 532         status = acpi_buffer_to_resource(achip->conn_info.connection,
 533                                          achip->conn_info.length, &ares);
 534         if (ACPI_FAILURE(status))
 535                 return status;
 536
 537         if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
 538                 ACPI_FREE(ares);
 539                 return AE_BAD_PARAMETER;
 540         }
 541
 542         agpio = &ares->data.gpio;
 543         pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
 544
 545         if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
 546             function == ACPI_WRITE)) {
 547                 ACPI_FREE(ares);
 548                 return AE_BAD_PARAMETER;
 549         }
 550
 551         length = min(agpio->pin_table_length, (u16)(pin_index + bits));
 552         for (i = pin_index; i < length; ++i) {
 553                 int pin = agpio->pin_table[i];
 554                 struct acpi_gpio_connection *conn;
 555                 struct gpio_desc *desc;
 556                 bool found;
 557
 558                 pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 559                 if (pin < 0) {
 560                         status = AE_BAD_PARAMETER;
 561                         goto out;
 562                 }
 563
 564                 mutex_lock(&achip->conn_lock);
 565
 566                 found = false;
 567                 list_for_each_entry(conn, &achip->conns, node) {
 568                         if (conn->pin == pin) {
 569                                 found = true;
 570                                 desc = conn->desc;
 571                                 break;
 572                         }
 573                 }
 574                 if (!found) {
 575                         desc = gpiochip_request_own_desc(chip, pin,
 576                                                          "ACPI:OpRegion");
 577                         if (IS_ERR(desc)) {
 578                                 status = AE_ERROR;
 579                                 mutex_unlock(&achip->conn_lock);
 580                                 goto out;
 581                         }
 582
 583                         switch (agpio->io_restriction) {
 584                         case ACPI_IO_RESTRICT_INPUT:
 585                                 gpiod_direction_input(desc);
 586                                 break;
 587                         case ACPI_IO_RESTRICT_OUTPUT:
 588                                 /*
 589                                  * ACPI GPIO resources don't contain an
 590                                  * initial value for the GPIO. Therefore we
 591                                  * deduce that value from the pull field
 592                                  * instead. If the pin is pulled up we
 593                                  * assume default to be high, otherwise
 594                                  * low.
 595                                  */
 596                                 gpiod_direction_output(desc, pull_up);
 597                                 break;
 598                         default:
 599                                 /*
 600                                  * Assume that the BIOS has configured the
 601                                  * direction and pull accordingly.
 602                                  */
 603                                 break;
 604                         }
 605
 606                         conn = kzalloc(sizeof(*conn), GFP_KERNEL);
 607                         if (!conn) {
 608                                 status = AE_NO_MEMORY;
 609                                 gpiochip_free_own_desc(desc);
 610                                 mutex_unlock(&achip->conn_lock);
 611                                 goto out;
 612                         }
 613
 614                         conn->pin = pin;
 615                         conn->desc = desc;
 616                         list_add_tail(&conn->node, &achip->conns);
 617                 }
 618
 619                 mutex_unlock(&achip->conn_lock);
 620
 621                 if (function == ACPI_WRITE)
 622                         gpiod_set_raw_value_cansleep(desc,
 623                                                      !!((1 << i) & *value));
 624                 else
 625                         *value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
 626         }
 627
 628 out:
 629         ACPI_FREE(ares);
 630         return status;
 631 }
 632
 633 static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
 634 {
 635         struct gpio_chip *chip = achip->chip;
 636         acpi_handle handle = ACPI_HANDLE(chip->dev);
 637         acpi_status status;
 638
 639         INIT_LIST_HEAD(&achip->conns);
 640         mutex_init(&achip->conn_lock);
 641         status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 642                                                     acpi_gpio_adr_space_handler,
 643                                                     NULL, achip);
 644         if (ACPI_FAILURE(status))
 645                 dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
 646 }
 647
 648 static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
 649 {
 650         struct gpio_chip *chip = achip->chip;
 651         acpi_handle handle = ACPI_HANDLE(chip->dev);
 652         struct acpi_gpio_connection *conn, *tmp;
 653         acpi_status status;
 654
 655         status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 656                                                    acpi_gpio_adr_space_handler);
 657         if (ACPI_FAILURE(status)) {
 658                 dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
 659                 return;
 660         }
 661
 662         list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
 663                 gpiochip_free_own_desc(conn->desc);
 664                 list_del(&conn->node);
 665                 kfree(conn);
 666         }
 667 }
 668
 669 void acpi_gpiochip_add(struct gpio_chip *chip)
 670 {
 671         struct acpi_gpio_chip *acpi_gpio;
 672         acpi_handle handle;
 673         acpi_status status;
 674
 675         if (!chip || !chip->dev)
 676                 return;
 677
 678         handle = ACPI_HANDLE(chip->dev);
 679         if (!handle)
 680                 return;
 681
 682         acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
 683         if (!acpi_gpio) {
 684                 dev_err(chip->dev,
 685                         "Failed to allocate memory for ACPI GPIO chip\n");
 686                 return;
 687         }
 688
 689         acpi_gpio->chip = chip;
 690
 691         status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
 692         if (ACPI_FAILURE(status)) {
 693                 dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
 694                 kfree(acpi_gpio);
 695                 return;
 696         }
 697
 698         acpi_gpiochip_request_regions(acpi_gpio);
 699 }
 700
 701 void acpi_gpiochip_remove(struct gpio_chip *chip)
 702 {
 703         struct acpi_gpio_chip *acpi_gpio;
 704         acpi_handle handle;
 705         acpi_status status;
 706
 707         if (!chip || !chip->dev)
 708                 return;
 709
 710         handle = ACPI_HANDLE(chip->dev);
 711         if (!handle)
 712                 return;
 713
 714         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 715         if (ACPI_FAILURE(status)) {
 716                 dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
 717                 return;
 718         }
 719
 720         acpi_gpiochip_free_regions(acpi_gpio);
 721
 722         acpi_detach_data(handle, acpi_gpio_chip_dh);
 723         kfree(acpi_gpio);
 724 }
 725
 726 static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
 727 {
 728         const union acpi_object *element = obj->package.elements;
 729         const union acpi_object *end = element + obj->package.count;
 730         unsigned int count = 0;
 731
 732         while (element < end) {
 733                 if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
 734                         count++;
 735
 736                 element++;
 737         }
 738         return count;
 739 }
 740
 741 static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
 742 {
 743         unsigned int *count = data;
 744
 745         if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
 746                 *count += ares->data.gpio.pin_table_length;
 747
 748         return 1;
 749 }
 750
 751 /**
 752  * acpi_gpio_count - return the number of GPIOs associated with a
 753  *              device / function or -ENOENT if no GPIO has been
 754  *              assigned to the requested function.
 755  * @dev:        GPIO consumer, can be NULL for system-global GPIOs
 756  * @con_id:     function within the GPIO consumer
 757  */
 758 int acpi_gpio_count(struct device *dev, const char *con_id)
 759 {
 760         struct acpi_device *adev = ACPI_COMPANION(dev);
 761         const union acpi_object *obj;
 762         const struct acpi_gpio_mapping *gm;
 763         int count = -ENOENT;
 764         int ret;
 765         char propname[32];
 766         unsigned int i;
 767
 768         /* Try first from _DSD */
 769         for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
 770                 if (con_id && strcmp(con_id, "gpios"))
 771                         snprintf(propname, sizeof(propname), "%s-%s",
 772                                  con_id, gpio_suffixes[i]);
 773                 else
 774                         snprintf(propname, sizeof(propname), "%s",
 775                                  gpio_suffixes[i]);
 776
 777                 ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
 778                                             &obj);
 779                 if (ret == 0) {
 780                         if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
 781                                 count = 1;
 782                         else if (obj->type == ACPI_TYPE_PACKAGE)
 783                                 count = acpi_gpio_package_count(obj);
 784                 } else if (adev->driver_gpios) {
 785                         for (gm = adev->driver_gpios; gm->name; gm++)
 786                                 if (strcmp(propname, gm->name) == 0) {
 787                                         count = gm->size;
 788                                         break;
 789                                 }
 790                 }
 791                 if (count >= 0)
 792                         break;
 793         }
 794
 795         /* Then from plain _CRS GPIOs */
 796         if (count < 0) {
 797                 struct list_head resource_list;
 798                 unsigned int crs_count = 0;
 799
 800                 INIT_LIST_HEAD(&resource_list);
 801                 acpi_dev_get_resources(adev, &resource_list,
 802                                        acpi_find_gpio_count, &crs_count);
 803                 acpi_dev_free_resource_list(&resource_list);
 804                 if (crs_count > 0)
 805                         count = crs_count;
 806         }
 807         return count;
 808 }