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/export.h>
  16 #include <linux/acpi_gpio.h>
  17 #include <linux/acpi.h>
  18 #include <linux/interrupt.h>
  19
  20 struct acpi_gpio_evt_pin {
  21         struct list_head node;
  22         acpi_handle *evt_handle;
  23         unsigned int pin;
  24         unsigned int irq;
  25 };
  26
  27 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
  28 {
  29         if (!gc->dev)
  30                 return false;
  31
  32         return ACPI_HANDLE(gc->dev) == data;
  33 }
  34
  35 /**
  36  * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
  37  * @path:       ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
  38  * @pin:        ACPI GPIO pin number (0-based, controller-relative)
  39  *
  40  * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
  41  * error value
  42  */
  43
  44 static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
  45 {
  46         struct gpio_chip *chip;
  47         acpi_handle handle;
  48         acpi_status status;
  49
  50         status = acpi_get_handle(NULL, path, &handle);
  51         if (ACPI_FAILURE(status))
  52                 return ERR_PTR(-ENODEV);
  53
  54         chip = gpiochip_find(handle, acpi_gpiochip_find);
  55         if (!chip)
  56                 return ERR_PTR(-ENODEV);
  57
  58         if (pin < 0 || pin > chip->ngpio)
  59                 return ERR_PTR(-EINVAL);
  60
  61         return gpio_to_desc(chip->base + pin);
  62 }
  63
  64 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
  65 {
  66         acpi_handle handle = data;
  67
  68         acpi_evaluate_object(handle, NULL, NULL, NULL);
  69
  70         return IRQ_HANDLED;
  71 }
  72
  73 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
  74 {
  75         struct acpi_gpio_evt_pin *evt_pin = data;
  76
  77         acpi_execute_simple_method(evt_pin->evt_handle, NULL, evt_pin->pin);
  78
  79         return IRQ_HANDLED;
  80 }
  81
  82 static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
  83 {
  84         /* The address of this function is used as a key. */
  85 }
  86
  87 /**
  88  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
  89  * @chip:      gpio chip
  90  *
  91  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
  92  * handled by ACPI event methods which need to be called from the GPIO
  93  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
  94  * gpio pins have acpi event methods and assigns interrupt handlers that calls
  95  * the acpi event methods for those pins.
  96  */
  97 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
  98 {
  99         struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
 100         struct acpi_resource *res;
 101         acpi_handle handle, evt_handle;
 102         struct list_head *evt_pins = NULL;
 103         acpi_status status;
 104         unsigned int pin;
 105         int irq, ret;
 106         char ev_name[5];
 107
 108         if (!chip->dev || !chip->to_irq)
 109                 return;
 110
 111         handle = ACPI_HANDLE(chip->dev);
 112         if (!handle)
 113                 return;
 114
 115         status = acpi_get_event_resources(handle, &buf);
 116         if (ACPI_FAILURE(status))
 117                 return;
 118
 119         status = acpi_get_handle(handle, "_EVT", &evt_handle);
 120         if (ACPI_SUCCESS(status)) {
 121                 evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
 122                 if (evt_pins) {
 123                         INIT_LIST_HEAD(evt_pins);
 124                         status = acpi_attach_data(handle, acpi_gpio_evt_dh,
 125                                                   evt_pins);
 126                         if (ACPI_FAILURE(status)) {
 127                                 kfree(evt_pins);
 128                                 evt_pins = NULL;
 129                         }
 130                 }
 131         }
 132
 133         /*
 134          * If a GPIO interrupt has an ACPI event handler method, or _EVT is
 135          * present, set up an interrupt handler that calls the ACPI event
 136          * handler.
 137          */
 138         for (res = buf.pointer;
 139              res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
 140              res = ACPI_NEXT_RESOURCE(res)) {
 141                 irq_handler_t handler = NULL;
 142                 void *data;
 143
 144                 if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
 145                     res->data.gpio.connection_type !=
 146                     ACPI_RESOURCE_GPIO_TYPE_INT)
 147                         continue;
 148
 149                 pin = res->data.gpio.pin_table[0];
 150                 if (pin > chip->ngpio)
 151                         continue;
 152
 153                 irq = chip->to_irq(chip, pin);
 154                 if (irq < 0)
 155                         continue;
 156
 157                 if (pin <= 255) {
 158                         acpi_handle ev_handle;
 159
 160                         sprintf(ev_name, "_%c%02X",
 161                                 res->data.gpio.triggering ? 'E' : 'L', pin);
 162                         status = acpi_get_handle(handle, ev_name, &ev_handle);
 163                         if (ACPI_SUCCESS(status)) {
 164                                 handler = acpi_gpio_irq_handler;
 165                                 data = ev_handle;
 166                         }
 167                 }
 168                 if (!handler && evt_pins) {
 169                         struct acpi_gpio_evt_pin *evt_pin;
 170
 171                         evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL);
 172                         if (!evt_pin)
 173                                 continue;
 174
 175                         list_add_tail(&evt_pin->node, evt_pins);
 176                         evt_pin->evt_handle = evt_handle;
 177                         evt_pin->pin = pin;
 178                         evt_pin->irq = irq;
 179                         handler = acpi_gpio_irq_handler_evt;
 180                         data = evt_pin;
 181                 }
 182                 if (!handler)
 183                         continue;
 184
 185                 /* Assume BIOS sets the triggering, so no flags */
 186                 ret = devm_request_threaded_irq(chip->dev, irq, NULL, handler,
 187                                                 0, "GPIO-signaled-ACPI-event",
 188                                                 data);
 189                 if (ret)
 190                         dev_err(chip->dev,
 191                                 "Failed to request IRQ %d ACPI event handler\n",
 192                                 irq);
 193         }
 194 }
 195 EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
 196
 197 /**
 198  * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
 199  * @chip:      gpio chip
 200  *
 201  * Free interrupts associated with the _EVT method for the given GPIO chip.
 202  *
 203  * The remaining ACPI event interrupts associated with the chip are freed
 204  * automatically.
 205  */
 206 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 207 {
 208         acpi_handle handle;
 209         acpi_status status;
 210         struct list_head *evt_pins;
 211         struct acpi_gpio_evt_pin *evt_pin, *ep;
 212
 213         if (!chip->dev || !chip->to_irq)
 214                 return;
 215
 216         handle = ACPI_HANDLE(chip->dev);
 217         if (!handle)
 218                 return;
 219
 220         status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
 221         if (ACPI_FAILURE(status))
 222                 return;
 223
 224         list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
 225                 devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
 226                 list_del(&evt_pin->node);
 227                 kfree(evt_pin);
 228         }
 229
 230         acpi_detach_data(handle, acpi_gpio_evt_dh);
 231         kfree(evt_pins);
 232 }
 233 EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);
 234
 235 struct acpi_gpio_lookup {
 236         struct acpi_gpio_info info;
 237         int index;
 238         struct gpio_desc *desc;
 239         int n;
 240 };
 241
 242 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 243 {
 244         struct acpi_gpio_lookup *lookup = data;
 245
 246         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 247                 return 1;
 248
 249         if (lookup->n++ == lookup->index && !lookup->desc) {
 250                 const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 251
 252                 lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
 253                                               agpio->pin_table[0]);
 254                 lookup->info.gpioint =
 255                         agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 256                 lookup->info.active_low =
 257                         agpio->polarity == ACPI_ACTIVE_LOW;
 258         }
 259
 260         return 1;
 261 }
 262
 263 /**
 264  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 265  * @dev: pointer to a device to get GPIO from
 266  * @index: index of GpioIo/GpioInt resource (starting from %0)
 267  * @info: info pointer to fill in (optional)
 268  *
 269  * Function goes through ACPI resources for @dev and based on @index looks
 270  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 271  * and returns it. @index matches GpioIo/GpioInt resources only so if there
 272  * are total %3 GPIO resources, the index goes from %0 to %2.
 273  *
 274  * If the GPIO cannot be translated or there is an error an ERR_PTR is
 275  * returned.
 276  *
 277  * Note: if the GPIO resource has multiple entries in the pin list, this
 278  * function only returns the first.
 279  */
 280 struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
 281                                           struct acpi_gpio_info *info)
 282 {
 283         struct acpi_gpio_lookup lookup;
 284         struct list_head resource_list;
 285         struct acpi_device *adev;
 286         acpi_handle handle;
 287         int ret;
 288
 289         if (!dev)
 290                 return ERR_PTR(-EINVAL);
 291
 292         handle = ACPI_HANDLE(dev);
 293         if (!handle || acpi_bus_get_device(handle, &adev))
 294                 return ERR_PTR(-ENODEV);
 295
 296         memset(&lookup, 0, sizeof(lookup));
 297         lookup.index = index;
 298
 299         INIT_LIST_HEAD(&resource_list);
 300         ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 301                                      &lookup);
 302         if (ret < 0)
 303                 return ERR_PTR(ret);
 304
 305         acpi_dev_free_resource_list(&resource_list);
 306
 307         if (lookup.desc && info)
 308                 *info = lookup.info;
 309
 310         return lookup.desc ? lookup.desc : ERR_PTR(-ENODEV);
 311 }
 312 EXPORT_SYMBOL_GPL(acpi_get_gpiod_by_index);