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 contiguous 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  * Return: GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
 118  * error value. Specifically returns %-EPROBE_DEFER if the referenced GPIO
 119  * controller does not have gpiochip registered at the moment. This is to
 120  * support probe deferral.
 121  */
 122 static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
 123 {
 124         struct gpio_chip *chip;
 125         acpi_handle handle;
 126         acpi_status status;
 127         int offset;
 128
 129         status = acpi_get_handle(NULL, path, &handle);
 130         if (ACPI_FAILURE(status))
 131                 return ERR_PTR(-ENODEV);
 132
 133         chip = gpiochip_find(handle, acpi_gpiochip_find);
 134         if (!chip)
 135                 return ERR_PTR(-EPROBE_DEFER);
 136
 137         offset = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 138         if (offset < 0)
 139                 return ERR_PTR(offset);
 140
 141         return gpiochip_get_desc(chip, offset);
 142 }
 143
 144 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
 145 {
 146         struct acpi_gpio_event *event = data;
 147
 148         acpi_evaluate_object(event->handle, NULL, NULL, NULL);
 149
 150         return IRQ_HANDLED;
 151 }
 152
 153 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
 154 {
 155         struct acpi_gpio_event *event = data;
 156
 157         acpi_execute_simple_method(event->handle, NULL, event->pin);
 158
 159         return IRQ_HANDLED;
 160 }
 161
 162 static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
 163 {
 164         /* The address of this function is used as a key. */
 165 }
 166
 167 static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
 168                                                    void *context)
 169 {
 170         struct acpi_gpio_chip *acpi_gpio = context;
 171         struct gpio_chip *chip = acpi_gpio->chip;
 172         struct acpi_resource_gpio *agpio;
 173         acpi_handle handle, evt_handle;
 174         struct acpi_gpio_event *event;
 175         irq_handler_t handler = NULL;
 176         struct gpio_desc *desc;
 177         unsigned long irqflags;
 178         int ret, pin, irq;
 179
 180         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 181                 return AE_OK;
 182
 183         agpio = &ares->data.gpio;
 184         if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
 185                 return AE_OK;
 186
 187         handle = ACPI_HANDLE(chip->dev);
 188         pin = agpio->pin_table[0];
 189
 190         if (pin <= 255) {
 191                 char ev_name[5];
 192                 sprintf(ev_name, "_%c%02X",
 193                         agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
 194                         pin);
 195                 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
 196                         handler = acpi_gpio_irq_handler;
 197         }
 198         if (!handler) {
 199                 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
 200                         handler = acpi_gpio_irq_handler_evt;
 201         }
 202         if (!handler)
 203                 return AE_BAD_PARAMETER;
 204
 205         pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 206         if (pin < 0)
 207                 return AE_BAD_PARAMETER;
 208
 209         desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
 210         if (IS_ERR(desc)) {
 211                 dev_err(chip->dev, "Failed to request GPIO\n");
 212                 return AE_ERROR;
 213         }
 214
 215         gpiod_direction_input(desc);
 216
 217         ret = gpiochip_lock_as_irq(chip, pin);
 218         if (ret) {
 219                 dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
 220                 goto fail_free_desc;
 221         }
 222
 223         irq = gpiod_to_irq(desc);
 224         if (irq < 0) {
 225                 dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
 226                 goto fail_unlock_irq;
 227         }
 228
 229         irqflags = IRQF_ONESHOT;
 230         if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
 231                 if (agpio->polarity == ACPI_ACTIVE_HIGH)
 232                         irqflags |= IRQF_TRIGGER_HIGH;
 233                 else
 234                         irqflags |= IRQF_TRIGGER_LOW;
 235         } else {
 236                 switch (agpio->polarity) {
 237                 case ACPI_ACTIVE_HIGH:
 238                         irqflags |= IRQF_TRIGGER_RISING;
 239                         break;
 240                 case ACPI_ACTIVE_LOW:
 241                         irqflags |= IRQF_TRIGGER_FALLING;
 242                         break;
 243                 default:
 244                         irqflags |= IRQF_TRIGGER_RISING |
 245                                     IRQF_TRIGGER_FALLING;
 246                         break;
 247                 }
 248         }
 249
 250         event = kzalloc(sizeof(*event), GFP_KERNEL);
 251         if (!event)
 252                 goto fail_unlock_irq;
 253
 254         event->handle = evt_handle;
 255         event->irq = irq;
 256         event->pin = pin;
 257         event->desc = desc;
 258
 259         ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
 260                                    "ACPI:Event", event);
 261         if (ret) {
 262                 dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
 263                         event->irq);
 264                 goto fail_free_event;
 265         }
 266
 267         list_add_tail(&event->node, &acpi_gpio->events);
 268         return AE_OK;
 269
 270 fail_free_event:
 271         kfree(event);
 272 fail_unlock_irq:
 273         gpiochip_unlock_as_irq(chip, pin);
 274 fail_free_desc:
 275         gpiochip_free_own_desc(desc);
 276
 277         return AE_ERROR;
 278 }
 279
 280 /**
 281  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
 282  * @chip:      GPIO chip
 283  *
 284  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
 285  * handled by ACPI event methods which need to be called from the GPIO
 286  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
 287  * gpio pins have acpi event methods and assigns interrupt handlers that calls
 288  * the acpi event methods for those pins.
 289  */
 290 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 291 {
 292         struct acpi_gpio_chip *acpi_gpio;
 293         acpi_handle handle;
 294         acpi_status status;
 295
 296         if (!chip->dev || !chip->to_irq)
 297                 return;
 298
 299         handle = ACPI_HANDLE(chip->dev);
 300         if (!handle)
 301                 return;
 302
 303         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 304         if (ACPI_FAILURE(status))
 305                 return;
 306
 307         acpi_walk_resources(handle, "_AEI",
 308                             acpi_gpiochip_request_interrupt, acpi_gpio);
 309 }
 310 EXPORT_SYMBOL_GPL(acpi_gpiochip_request_interrupts);
 311
 312 /**
 313  * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
 314  * @chip:      GPIO chip
 315  *
 316  * Free interrupts associated with GPIO ACPI event method for the given
 317  * GPIO chip.
 318  */
 319 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 320 {
 321         struct acpi_gpio_chip *acpi_gpio;
 322         struct acpi_gpio_event *event, *ep;
 323         acpi_handle handle;
 324         acpi_status status;
 325
 326         if (!chip->dev || !chip->to_irq)
 327                 return;
 328
 329         handle = ACPI_HANDLE(chip->dev);
 330         if (!handle)
 331                 return;
 332
 333         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 334         if (ACPI_FAILURE(status))
 335                 return;
 336
 337         list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
 338                 struct gpio_desc *desc;
 339
 340                 free_irq(event->irq, event);
 341                 desc = event->desc;
 342                 if (WARN_ON(IS_ERR(desc)))
 343                         continue;
 344                 gpiochip_unlock_as_irq(chip, event->pin);
 345                 gpiochip_free_own_desc(desc);
 346                 list_del(&event->node);
 347                 kfree(event);
 348         }
 349 }
 350 EXPORT_SYMBOL_GPL(acpi_gpiochip_free_interrupts);
 351
 352 int acpi_dev_add_driver_gpios(struct acpi_device *adev,
 353                               const struct acpi_gpio_mapping *gpios)
 354 {
 355         if (adev && gpios) {
 356                 adev->driver_gpios = gpios;
 357                 return 0;
 358         }
 359         return -EINVAL;
 360 }
 361 EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);
 362
 363 static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
 364                                       const char *name, int index,
 365                                       struct acpi_reference_args *args)
 366 {
 367         const struct acpi_gpio_mapping *gm;
 368
 369         if (!adev->driver_gpios)
 370                 return false;
 371
 372         for (gm = adev->driver_gpios; gm->name; gm++)
 373                 if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
 374                         const struct acpi_gpio_params *par = gm->data + index;
 375
 376                         args->adev = adev;
 377                         args->args[0] = par->crs_entry_index;
 378                         args->args[1] = par->line_index;
 379                         args->args[2] = par->active_low;
 380                         args->nargs = 3;
 381                         return true;
 382                 }
 383
 384         return false;
 385 }
 386
 387 struct acpi_gpio_lookup {
 388         struct acpi_gpio_info info;
 389         int index;
 390         int pin_index;
 391         bool active_low;
 392         struct acpi_device *adev;
 393         struct gpio_desc *desc;
 394         int n;
 395 };
 396
 397 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 398 {
 399         struct acpi_gpio_lookup *lookup = data;
 400
 401         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 402                 return 1;
 403
 404         if (lookup->n++ == lookup->index && !lookup->desc) {
 405                 const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 406                 int pin_index = lookup->pin_index;
 407
 408                 if (pin_index >= agpio->pin_table_length)
 409                         return 1;
 410
 411                 lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
 412                                               agpio->pin_table[pin_index]);
 413                 lookup->info.gpioint =
 414                         agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 415
 416                 /*
 417                  * ActiveLow is only specified for GpioInt resource. If
 418                  * GpioIo is used then the only way to set the flag is
 419                  * to use _DSD "gpios" property.
 420                  */
 421                 if (lookup->info.gpioint)
 422                         lookup->info.active_low =
 423                                 agpio->polarity == ACPI_ACTIVE_LOW;
 424         }
 425
 426         return 1;
 427 }
 428
 429 static int acpi_gpio_resource_lookup(struct acpi_gpio_lookup *lookup,
 430                                      struct acpi_gpio_info *info)
 431 {
 432         struct list_head res_list;
 433         int ret;
 434
 435         INIT_LIST_HEAD(&res_list);
 436
 437         ret = acpi_dev_get_resources(lookup->adev, &res_list, acpi_find_gpio,
 438                                      lookup);
 439         if (ret < 0)
 440                 return ret;
 441
 442         acpi_dev_free_resource_list(&res_list);
 443
 444         if (!lookup->desc)
 445                 return -ENOENT;
 446
 447         if (info) {
 448                 *info = lookup->info;
 449                 if (lookup->active_low)
 450                         info->active_low = lookup->active_low;
 451         }
 452         return 0;
 453 }
 454
 455 static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
 456                                      const char *propname, int index,
 457                                      struct acpi_gpio_lookup *lookup)
 458 {
 459         struct acpi_reference_args args;
 460         int ret;
 461
 462         memset(&args, 0, sizeof(args));
 463         ret = acpi_node_get_property_reference(fwnode, propname, index, &args);
 464         if (ret) {
 465                 struct acpi_device *adev = to_acpi_device_node(fwnode);
 466
 467                 if (!adev)
 468                         return ret;
 469
 470                 if (!acpi_get_driver_gpio_data(adev, propname, index, &args))
 471                         return ret;
 472         }
 473         /*
 474          * The property was found and resolved, so need to lookup the GPIO based
 475          * on returned args.
 476          */
 477         lookup->adev = args.adev;
 478         if (args.nargs >= 2) {
 479                 lookup->index = args.args[0];
 480                 lookup->pin_index = args.args[1];
 481                 /* 3rd argument, if present is used to specify active_low. */
 482                 if (args.nargs >= 3)
 483                         lookup->active_low = !!args.args[2];
 484         }
 485         return 0;
 486 }
 487
 488 /**
 489  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 490  * @adev: pointer to a ACPI device to get GPIO from
 491  * @propname: Property name of the GPIO (optional)
 492  * @index: index of GpioIo/GpioInt resource (starting from %0)
 493  * @info: info pointer to fill in (optional)
 494  *
 495  * Function goes through ACPI resources for @adev and based on @index looks
 496  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 497  * and returns it. @index matches GpioIo/GpioInt resources only so if there
 498  * are total %3 GPIO resources, the index goes from %0 to %2.
 499  *
 500  * If @propname is specified the GPIO is looked using device property. In
 501  * that case @index is used to select the GPIO entry in the property value
 502  * (in case of multiple).
 503  *
 504  * If the GPIO cannot be translated or there is an error an ERR_PTR is
 505  * returned.
 506  *
 507  * Note: if the GPIO resource has multiple entries in the pin list, this
 508  * function only returns the first.
 509  */
 510 struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
 511                                           const char *propname, int index,
 512                                           struct acpi_gpio_info *info)
 513 {
 514         struct acpi_gpio_lookup lookup;
 515         int ret;
 516
 517         if (!adev)
 518                 return ERR_PTR(-ENODEV);
 519
 520         memset(&lookup, 0, sizeof(lookup));
 521         lookup.index = index;
 522
 523         if (propname) {
 524                 dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
 525
 526                 ret = acpi_gpio_property_lookup(acpi_fwnode_handle(adev),
 527                                                 propname, index, &lookup);
 528                 if (ret)
 529                         return ERR_PTR(ret);
 530
 531                 dev_dbg(&adev->dev, "GPIO: _DSD returned %s %d %d %u\n",
 532                         dev_name(&lookup.adev->dev), lookup.index,
 533                         lookup.pin_index, lookup.active_low);
 534         } else {
 535                 dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
 536                 lookup.adev = adev;
 537         }
 538
 539         ret = acpi_gpio_resource_lookup(&lookup, info);
 540         return ret ? ERR_PTR(ret) : lookup.desc;
 541 }
 542
 543 /**
 544  * acpi_node_get_gpiod() - get a GPIO descriptor from ACPI resources
 545  * @fwnode: pointer to an ACPI firmware node to get the GPIO information from
 546  * @propname: Property name of the GPIO
 547  * @index: index of GpioIo/GpioInt resource (starting from %0)
 548  * @info: info pointer to fill in (optional)
 549  *
 550  * If @fwnode is an ACPI device object, call %acpi_get_gpiod_by_index() for it.
 551  * Otherwise (ie. it is a data-only non-device object), use the property-based
 552  * GPIO lookup to get to the GPIO resource with the relevant information and use
 553  * that to obtain the GPIO descriptor to return.
 554  */
 555 struct gpio_desc *acpi_node_get_gpiod(struct fwnode_handle *fwnode,
 556                                       const char *propname, int index,
 557                                       struct acpi_gpio_info *info)
 558 {
 559         struct acpi_gpio_lookup lookup;
 560         struct acpi_device *adev;
 561         int ret;
 562
 563         adev = to_acpi_device_node(fwnode);
 564         if (adev)
 565                 return acpi_get_gpiod_by_index(adev, propname, index, info);
 566
 567         if (!is_acpi_data_node(fwnode))
 568                 return ERR_PTR(-ENODEV);
 569
 570         if (!propname)
 571                 return ERR_PTR(-EINVAL);
 572
 573         memset(&lookup, 0, sizeof(lookup));
 574         lookup.index = index;
 575
 576         ret = acpi_gpio_property_lookup(fwnode, propname, index, &lookup);
 577         if (ret)
 578                 return ERR_PTR(ret);
 579
 580         ret = acpi_gpio_resource_lookup(&lookup, info);
 581         return ret ? ERR_PTR(ret) : lookup.desc;
 582 }
 583
 584 /**
 585  * acpi_dev_gpio_irq_get() - Find GpioInt and translate it to Linux IRQ number
 586  * @adev: pointer to a ACPI device to get IRQ from
 587  * @index: index of GpioInt resource (starting from %0)
 588  *
 589  * If the device has one or more GpioInt resources, this function can be
 590  * used to translate from the GPIO offset in the resource to the Linux IRQ
 591  * number.
 592  *
 593  * Return: Linux IRQ number (>%0) on success, negative errno on failure.
 594  */
 595 int acpi_dev_gpio_irq_get(struct acpi_device *adev, int index)
 596 {
 597         int idx, i;
 598
 599         for (i = 0, idx = 0; idx <= index; i++) {
 600                 struct acpi_gpio_info info;
 601                 struct gpio_desc *desc;
 602
 603                 desc = acpi_get_gpiod_by_index(adev, NULL, i, &info);
 604                 if (IS_ERR(desc))
 605                         break;
 606                 if (info.gpioint && idx++ == index)
 607                         return gpiod_to_irq(desc);
 608         }
 609         return -ENOENT;
 610 }
 611 EXPORT_SYMBOL_GPL(acpi_dev_gpio_irq_get);
 612
 613 static acpi_status
 614 acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
 615                             u32 bits, u64 *value, void *handler_context,
 616                             void *region_context)
 617 {
 618         struct acpi_gpio_chip *achip = region_context;
 619         struct gpio_chip *chip = achip->chip;
 620         struct acpi_resource_gpio *agpio;
 621         struct acpi_resource *ares;
 622         int pin_index = (int)address;
 623         acpi_status status;
 624         bool pull_up;
 625         int length;
 626         int i;
 627
 628         status = acpi_buffer_to_resource(achip->conn_info.connection,
 629                                          achip->conn_info.length, &ares);
 630         if (ACPI_FAILURE(status))
 631                 return status;
 632
 633         if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
 634                 ACPI_FREE(ares);
 635                 return AE_BAD_PARAMETER;
 636         }
 637
 638         agpio = &ares->data.gpio;
 639         pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
 640
 641         if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
 642             function == ACPI_WRITE)) {
 643                 ACPI_FREE(ares);
 644                 return AE_BAD_PARAMETER;
 645         }
 646
 647         length = min(agpio->pin_table_length, (u16)(pin_index + bits));
 648         for (i = pin_index; i < length; ++i) {
 649                 int pin = agpio->pin_table[i];
 650                 struct acpi_gpio_connection *conn;
 651                 struct gpio_desc *desc;
 652                 bool found;
 653
 654                 pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
 655                 if (pin < 0) {
 656                         status = AE_BAD_PARAMETER;
 657                         goto out;
 658                 }
 659
 660                 mutex_lock(&achip->conn_lock);
 661
 662                 found = false;
 663                 list_for_each_entry(conn, &achip->conns, node) {
 664                         if (conn->pin == pin) {
 665                                 found = true;
 666                                 desc = conn->desc;
 667                                 break;
 668                         }
 669                 }
 670
 671                 /*
 672                  * The same GPIO can be shared between operation region and
 673                  * event but only if the access here is ACPI_READ. In that
 674                  * case we "borrow" the event GPIO instead.
 675                  */
 676                 if (!found && agpio->sharable == ACPI_SHARED &&
 677                      function == ACPI_READ) {
 678                         struct acpi_gpio_event *event;
 679
 680                         list_for_each_entry(event, &achip->events, node) {
 681                                 if (event->pin == pin) {
 682                                         desc = event->desc;
 683                                         found = true;
 684                                         break;
 685                                 }
 686                         }
 687                 }
 688
 689                 if (!found) {
 690                         desc = gpiochip_request_own_desc(chip, pin,
 691                                                          "ACPI:OpRegion");
 692                         if (IS_ERR(desc)) {
 693                                 status = AE_ERROR;
 694                                 mutex_unlock(&achip->conn_lock);
 695                                 goto out;
 696                         }
 697
 698                         switch (agpio->io_restriction) {
 699                         case ACPI_IO_RESTRICT_INPUT:
 700                                 gpiod_direction_input(desc);
 701                                 break;
 702                         case ACPI_IO_RESTRICT_OUTPUT:
 703                                 /*
 704                                  * ACPI GPIO resources don't contain an
 705                                  * initial value for the GPIO. Therefore we
 706                                  * deduce that value from the pull field
 707                                  * instead. If the pin is pulled up we
 708                                  * assume default to be high, otherwise
 709                                  * low.
 710                                  */
 711                                 gpiod_direction_output(desc, pull_up);
 712                                 break;
 713                         default:
 714                                 /*
 715                                  * Assume that the BIOS has configured the
 716                                  * direction and pull accordingly.
 717                                  */
 718                                 break;
 719                         }
 720
 721                         conn = kzalloc(sizeof(*conn), GFP_KERNEL);
 722                         if (!conn) {
 723                                 status = AE_NO_MEMORY;
 724                                 gpiochip_free_own_desc(desc);
 725                                 mutex_unlock(&achip->conn_lock);
 726                                 goto out;
 727                         }
 728
 729                         conn->pin = pin;
 730                         conn->desc = desc;
 731                         list_add_tail(&conn->node, &achip->conns);
 732                 }
 733
 734                 mutex_unlock(&achip->conn_lock);
 735
 736                 if (function == ACPI_WRITE)
 737                         gpiod_set_raw_value_cansleep(desc,
 738                                                      !!((1 << i) & *value));
 739                 else
 740                         *value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
 741         }
 742
 743 out:
 744         ACPI_FREE(ares);
 745         return status;
 746 }
 747
 748 static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
 749 {
 750         struct gpio_chip *chip = achip->chip;
 751         acpi_handle handle = ACPI_HANDLE(chip->dev);
 752         acpi_status status;
 753
 754         INIT_LIST_HEAD(&achip->conns);
 755         mutex_init(&achip->conn_lock);
 756         status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 757                                                     acpi_gpio_adr_space_handler,
 758                                                     NULL, achip);
 759         if (ACPI_FAILURE(status))
 760                 dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
 761 }
 762
 763 static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
 764 {
 765         struct gpio_chip *chip = achip->chip;
 766         acpi_handle handle = ACPI_HANDLE(chip->dev);
 767         struct acpi_gpio_connection *conn, *tmp;
 768         acpi_status status;
 769
 770         status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
 771                                                    acpi_gpio_adr_space_handler);
 772         if (ACPI_FAILURE(status)) {
 773                 dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
 774                 return;
 775         }
 776
 777         list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
 778                 gpiochip_free_own_desc(conn->desc);
 779                 list_del(&conn->node);
 780                 kfree(conn);
 781         }
 782 }
 783
 784 void acpi_gpiochip_add(struct gpio_chip *chip)
 785 {
 786         struct acpi_gpio_chip *acpi_gpio;
 787         acpi_handle handle;
 788         acpi_status status;
 789
 790         if (!chip || !chip->dev)
 791                 return;
 792
 793         handle = ACPI_HANDLE(chip->dev);
 794         if (!handle)
 795                 return;
 796
 797         acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
 798         if (!acpi_gpio) {
 799                 dev_err(chip->dev,
 800                         "Failed to allocate memory for ACPI GPIO chip\n");
 801                 return;
 802         }
 803
 804         acpi_gpio->chip = chip;
 805         INIT_LIST_HEAD(&acpi_gpio->events);
 806
 807         status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
 808         if (ACPI_FAILURE(status)) {
 809                 dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
 810                 kfree(acpi_gpio);
 811                 return;
 812         }
 813
 814         acpi_gpiochip_request_regions(acpi_gpio);
 815 }
 816
 817 void acpi_gpiochip_remove(struct gpio_chip *chip)
 818 {
 819         struct acpi_gpio_chip *acpi_gpio;
 820         acpi_handle handle;
 821         acpi_status status;
 822
 823         if (!chip || !chip->dev)
 824                 return;
 825
 826         handle = ACPI_HANDLE(chip->dev);
 827         if (!handle)
 828                 return;
 829
 830         status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
 831         if (ACPI_FAILURE(status)) {
 832                 dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
 833                 return;
 834         }
 835
 836         acpi_gpiochip_free_regions(acpi_gpio);
 837
 838         acpi_detach_data(handle, acpi_gpio_chip_dh);
 839         kfree(acpi_gpio);
 840 }
 841
 842 static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
 843 {
 844         const union acpi_object *element = obj->package.elements;
 845         const union acpi_object *end = element + obj->package.count;
 846         unsigned int count = 0;
 847
 848         while (element < end) {
 849                 if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
 850                         count++;
 851
 852                 element++;
 853         }
 854         return count;
 855 }
 856
 857 static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
 858 {
 859         unsigned int *count = data;
 860
 861         if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
 862                 *count += ares->data.gpio.pin_table_length;
 863
 864         return 1;
 865 }
 866
 867 /**
 868  * acpi_gpio_count - return the number of GPIOs associated with a
 869  *              device / function or -ENOENT if no GPIO has been
 870  *              assigned to the requested function.
 871  * @dev:        GPIO consumer, can be NULL for system-global GPIOs
 872  * @con_id:     function within the GPIO consumer
 873  */
 874 int acpi_gpio_count(struct device *dev, const char *con_id)
 875 {
 876         struct acpi_device *adev = ACPI_COMPANION(dev);
 877         const union acpi_object *obj;
 878         const struct acpi_gpio_mapping *gm;
 879         int count = -ENOENT;
 880         int ret;
 881         char propname[32];
 882         unsigned int i;
 883
 884         /* Try first from _DSD */
 885         for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
 886                 if (con_id && strcmp(con_id, "gpios"))
 887                         snprintf(propname, sizeof(propname), "%s-%s",
 888                                  con_id, gpio_suffixes[i]);
 889                 else
 890                         snprintf(propname, sizeof(propname), "%s",
 891                                  gpio_suffixes[i]);
 892
 893                 ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
 894                                             &obj);
 895                 if (ret == 0) {
 896                         if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
 897                                 count = 1;
 898                         else if (obj->type == ACPI_TYPE_PACKAGE)
 899                                 count = acpi_gpio_package_count(obj);
 900                 } else if (adev->driver_gpios) {
 901                         for (gm = adev->driver_gpios; gm->name; gm++)
 902                                 if (strcmp(propname, gm->name) == 0) {
 903                                         count = gm->size;
 904                                         break;
 905                                 }
 906                 }
 907                 if (count >= 0)
 908                         break;
 909         }
 910
 911         /* Then from plain _CRS GPIOs */
 912         if (count < 0) {
 913                 struct list_head resource_list;
 914                 unsigned int crs_count = 0;
 915
 916                 INIT_LIST_HEAD(&resource_list);
 917                 acpi_dev_get_resources(adev, &resource_list,
 918                                        acpi_find_gpio_count, &crs_count);
 919                 acpi_dev_free_resource_list(&resource_list);
 920                 if (crs_count > 0)
 921                         count = crs_count;
 922         }
 923         return count;
 924 }