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/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_gpio() - Translate ACPI GPIO pin to GPIO number 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 number to use with Linux generic GPIO API, or errno error value
  41  */
  42
  43 int acpi_get_gpio(char *path, int pin)
  44 {
  45         struct gpio_chip *chip;
  46         acpi_handle handle;
  47         acpi_status status;
  48
  49         status = acpi_get_handle(NULL, path, &handle);
  50         if (ACPI_FAILURE(status))
  51                 return -ENODEV;
  52
  53         chip = gpiochip_find(handle, acpi_gpiochip_find);
  54         if (!chip)
  55                 return -ENODEV;
  56
  57         if (!gpio_is_valid(chip->base + pin))
  58                 return -EINVAL;
  59
  60         return chip->base + pin;
  61 }
  62 EXPORT_SYMBOL_GPL(acpi_get_gpio);
  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         struct acpi_object_list args;
  77         union acpi_object arg;
  78
  79         arg.type = ACPI_TYPE_INTEGER;
  80         arg.integer.value = evt_pin->pin;
  81         args.count = 1;
  82         args.pointer = &arg;
  83
  84         acpi_evaluate_object(evt_pin->evt_handle, NULL, &args, NULL);
  85
  86         return IRQ_HANDLED;
  87 }
  88
  89 static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
  90 {
  91         /* The address of this function is used as a key. */
  92 }
  93
  94 /**
  95  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
  96  * @chip:      gpio chip
  97  *
  98  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
  99  * handled by ACPI event methods which need to be called from the GPIO
 100  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
 101  * gpio pins have acpi event methods and assigns interrupt handlers that calls
 102  * the acpi event methods for those pins.
 103  */
 104 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
 105 {
 106         struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
 107         struct acpi_resource *res;
 108         acpi_handle handle, evt_handle;
 109         struct list_head *evt_pins = NULL;
 110         acpi_status status;
 111         unsigned int pin;
 112         int irq, ret;
 113         char ev_name[5];
 114
 115         if (!chip->dev || !chip->to_irq)
 116                 return;
 117
 118         handle = ACPI_HANDLE(chip->dev);
 119         if (!handle)
 120                 return;
 121
 122         status = acpi_get_event_resources(handle, &buf);
 123         if (ACPI_FAILURE(status))
 124                 return;
 125
 126         status = acpi_get_handle(handle, "_EVT", &evt_handle);
 127         if (ACPI_SUCCESS(status)) {
 128                 evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
 129                 if (evt_pins) {
 130                         INIT_LIST_HEAD(evt_pins);
 131                         status = acpi_attach_data(handle, acpi_gpio_evt_dh,
 132                                                   evt_pins);
 133                         if (ACPI_FAILURE(status)) {
 134                                 kfree(evt_pins);
 135                                 evt_pins = NULL;
 136                         }
 137                 }
 138         }
 139
 140         /*
 141          * If a GPIO interrupt has an ACPI event handler method, or _EVT is
 142          * present, set up an interrupt handler that calls the ACPI event
 143          * handler.
 144          */
 145         for (res = buf.pointer;
 146              res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
 147              res = ACPI_NEXT_RESOURCE(res)) {
 148                 irq_handler_t handler = NULL;
 149                 void *data;
 150
 151                 if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
 152                     res->data.gpio.connection_type !=
 153                     ACPI_RESOURCE_GPIO_TYPE_INT)
 154                         continue;
 155
 156                 pin = res->data.gpio.pin_table[0];
 157                 if (pin > chip->ngpio)
 158                         continue;
 159
 160                 irq = chip->to_irq(chip, pin);
 161                 if (irq < 0)
 162                         continue;
 163
 164                 if (pin <= 255) {
 165                         acpi_handle ev_handle;
 166
 167                         sprintf(ev_name, "_%c%02X",
 168                                 res->data.gpio.triggering ? 'E' : 'L', pin);
 169                         status = acpi_get_handle(handle, ev_name, &ev_handle);
 170                         if (ACPI_SUCCESS(status)) {
 171                                 handler = acpi_gpio_irq_handler;
 172                                 data = ev_handle;
 173                         }
 174                 }
 175                 if (!handler && evt_pins) {
 176                         struct acpi_gpio_evt_pin *evt_pin;
 177
 178                         evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL);
 179                         if (!evt_pin)
 180                                 continue;
 181
 182                         list_add_tail(&evt_pin->node, evt_pins);
 183                         evt_pin->evt_handle = evt_handle;
 184                         evt_pin->pin = pin;
 185                         evt_pin->irq = irq;
 186                         handler = acpi_gpio_irq_handler_evt;
 187                         data = evt_pin;
 188                 }
 189                 if (!handler)
 190                         continue;
 191
 192                 /* Assume BIOS sets the triggering, so no flags */
 193                 ret = devm_request_threaded_irq(chip->dev, irq, NULL, handler,
 194                                                 0, "GPIO-signaled-ACPI-event",
 195                                                 data);
 196                 if (ret)
 197                         dev_err(chip->dev,
 198                                 "Failed to request IRQ %d ACPI event handler\n",
 199                                 irq);
 200         }
 201 }
 202 EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);
 203
 204 struct acpi_gpio_lookup {
 205         struct acpi_gpio_info info;
 206         int index;
 207         int gpio;
 208         int n;
 209 };
 210
 211 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
 212 {
 213         struct acpi_gpio_lookup *lookup = data;
 214
 215         if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
 216                 return 1;
 217
 218         if (lookup->n++ == lookup->index && lookup->gpio < 0) {
 219                 const struct acpi_resource_gpio *agpio = &ares->data.gpio;
 220
 221                 lookup->gpio = acpi_get_gpio(agpio->resource_source.string_ptr,
 222                                              agpio->pin_table[0]);
 223                 lookup->info.gpioint =
 224                         agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
 225         }
 226
 227         return 1;
 228 }
 229
 230 /**
 231  * acpi_get_gpio_by_index() - get a GPIO number from device resources
 232  * @dev: pointer to a device to get GPIO from
 233  * @index: index of GpioIo/GpioInt resource (starting from %0)
 234  * @info: info pointer to fill in (optional)
 235  *
 236  * Function goes through ACPI resources for @dev and based on @index looks
 237  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO number,
 238  * and returns it. @index matches GpioIo/GpioInt resources only so if there
 239  * are total %3 GPIO resources, the index goes from %0 to %2.
 240  *
 241  * If the GPIO cannot be translated or there is an error, negative errno is
 242  * returned.
 243  *
 244  * Note: if the GPIO resource has multiple entries in the pin list, this
 245  * function only returns the first.
 246  */
 247 int acpi_get_gpio_by_index(struct device *dev, int index,
 248                            struct acpi_gpio_info *info)
 249 {
 250         struct acpi_gpio_lookup lookup;
 251         struct list_head resource_list;
 252         struct acpi_device *adev;
 253         acpi_handle handle;
 254         int ret;
 255
 256         if (!dev)
 257                 return -EINVAL;
 258
 259         handle = ACPI_HANDLE(dev);
 260         if (!handle || acpi_bus_get_device(handle, &adev))
 261                 return -ENODEV;
 262
 263         memset(&lookup, 0, sizeof(lookup));
 264         lookup.index = index;
 265         lookup.gpio = -ENODEV;
 266
 267         INIT_LIST_HEAD(&resource_list);
 268         ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
 269                                      &lookup);
 270         if (ret < 0)
 271                 return ret;
 272
 273         acpi_dev_free_resource_list(&resource_list);
 274
 275         if (lookup.gpio >= 0 && info)
 276                 *info = lookup.info;
 277
 278         return lookup.gpio;
 279 }
 280 EXPORT_SYMBOL_GPL(acpi_get_gpio_by_index);
 281
 282 /**
 283  * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
 284  * @chip:      gpio chip
 285  *
 286  * Free interrupts associated with the _EVT method for the given GPIO chip.
 287  *
 288  * The remaining ACPI event interrupts associated with the chip are freed
 289  * automatically.
 290  */
 291 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
 292 {
 293         acpi_handle handle;
 294         acpi_status status;
 295         struct list_head *evt_pins;
 296         struct acpi_gpio_evt_pin *evt_pin, *ep;
 297
 298         if (!chip->dev || !chip->to_irq)
 299                 return;
 300
 301         handle = ACPI_HANDLE(chip->dev);
 302         if (!handle)
 303                 return;
 304
 305         status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
 306         if (ACPI_FAILURE(status))
 307                 return;
 308
 309         list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
 310                 devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
 311                 list_del(&evt_pin->node);
 312                 kfree(evt_pin);
 313         }
 314
 315         acpi_detach_data(handle, acpi_gpio_evt_dh);
 316         kfree(evt_pins);
 317 }
 318 EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);