drivers/gpio/gpiolib-acpi.c

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