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 20 #include "gpiolib.h" 21 22 struct acpi_gpio_evt_pin { 23 struct list_head node; 24 acpi_handle *evt_handle; 25 unsigned int pin; 26 unsigned int irq; 27 }; 28 29 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data) 30 { 31 if (!gc->dev) 32 return false; 33 34 return ACPI_HANDLE(gc->dev) == data; 35 } 36 37 /** 38 * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API 39 * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1") 40 * @pin: ACPI GPIO pin number (0-based, controller-relative) 41 * 42 * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR 43 * error value 44 */ 45 46 static struct gpio_desc *acpi_get_gpiod(char *path, int pin) 47 { 48 struct gpio_chip *chip; 49 acpi_handle handle; 50 acpi_status status; 51 52 status = acpi_get_handle(NULL, path, &handle); 53 if (ACPI_FAILURE(status)) 54 return ERR_PTR(-ENODEV); 55 56 chip = gpiochip_find(handle, acpi_gpiochip_find); 57 if (!chip) 58 return ERR_PTR(-ENODEV); 59 60 if (pin < 0 || pin > chip->ngpio) 61 return ERR_PTR(-EINVAL); 62 63 return gpio_to_desc(chip->base + pin); 64 } 65 66 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data) 67 { 68 acpi_handle handle = data; 69 70 acpi_evaluate_object(handle, NULL, NULL, NULL); 71 72 return IRQ_HANDLED; 73 } 74 75 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data) 76 { 77 struct acpi_gpio_evt_pin *evt_pin = data; 78 79 acpi_execute_simple_method(evt_pin->evt_handle, NULL, evt_pin->pin); 80 81 return IRQ_HANDLED; 82 } 83 84 static void acpi_gpio_evt_dh(acpi_handle handle, void *data) 85 { 86 /* The address of this function is used as a key. */ 87 } 88 89 /** 90 * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events 91 * @chip: gpio chip 92 * 93 * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are 94 * handled by ACPI event methods which need to be called from the GPIO 95 * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which 96 * gpio pins have acpi event methods and assigns interrupt handlers that calls 97 * the acpi event methods for those pins. 98 */ 99 static void acpi_gpiochip_request_interrupts(struct gpio_chip *chip) 100 { 101 struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL}; 102 struct acpi_resource *res; 103 acpi_handle handle, evt_handle; 104 struct list_head *evt_pins = NULL; 105 acpi_status status; 106 unsigned int pin; 107 int irq, ret; 108 char ev_name[5]; 109 110 if (!chip->dev || !chip->to_irq) 111 return; 112 113 handle = ACPI_HANDLE(chip->dev); 114 if (!handle) 115 return; 116 117 status = acpi_get_event_resources(handle, &buf); 118 if (ACPI_FAILURE(status)) 119 return; 120 121 status = acpi_get_handle(handle, "_EVT", &evt_handle); 122 if (ACPI_SUCCESS(status)) { 123 evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL); 124 if (evt_pins) { 125 INIT_LIST_HEAD(evt_pins); 126 status = acpi_attach_data(handle, acpi_gpio_evt_dh, 127 evt_pins); 128 if (ACPI_FAILURE(status)) { 129 kfree(evt_pins); 130 evt_pins = NULL; 131 } 132 } 133 } 134 135 /* 136 * If a GPIO interrupt has an ACPI event handler method, or _EVT is 137 * present, set up an interrupt handler that calls the ACPI event 138 * handler. 139 */ 140 for (res = buf.pointer; 141 res && (res->type != ACPI_RESOURCE_TYPE_END_TAG); 142 res = ACPI_NEXT_RESOURCE(res)) { 143 irq_handler_t handler = NULL; 144 void *data; 145 146 if (res->type != ACPI_RESOURCE_TYPE_GPIO || 147 res->data.gpio.connection_type != 148 ACPI_RESOURCE_GPIO_TYPE_INT) 149 continue; 150 151 pin = res->data.gpio.pin_table[0]; 152 if (pin > chip->ngpio) 153 continue; 154 155 irq = chip->to_irq(chip, pin); 156 if (irq < 0) 157 continue; 158 159 if (pin <= 255) { 160 acpi_handle ev_handle; 161 162 sprintf(ev_name, "_%c%02X", 163 res->data.gpio.triggering ? 'E' : 'L', pin); 164 status = acpi_get_handle(handle, ev_name, &ev_handle); 165 if (ACPI_SUCCESS(status)) { 166 handler = acpi_gpio_irq_handler; 167 data = ev_handle; 168 } 169 } 170 if (!handler && evt_pins) { 171 struct acpi_gpio_evt_pin *evt_pin; 172 173 evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL); 174 if (!evt_pin) 175 continue; 176 177 list_add_tail(&evt_pin->node, evt_pins); 178 evt_pin->evt_handle = evt_handle; 179 evt_pin->pin = pin; 180 evt_pin->irq = irq; 181 handler = acpi_gpio_irq_handler_evt; 182 data = evt_pin; 183 } 184 if (!handler) 185 continue; 186 187 /* Assume BIOS sets the triggering, so no flags */ 188 ret = devm_request_threaded_irq(chip->dev, irq, NULL, handler, 189 0, "GPIO-signaled-ACPI-event", 190 data); 191 if (ret) 192 dev_err(chip->dev, 193 "Failed to request IRQ %d ACPI event handler\n", 194 irq); 195 } 196 } 197 198 /** 199 * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts. 200 * @chip: gpio chip 201 * 202 * Free interrupts associated with the _EVT method for the given GPIO chip. 203 * 204 * The remaining ACPI event interrupts associated with the chip are freed 205 * automatically. 206 */ 207 static void acpi_gpiochip_free_interrupts(struct gpio_chip *chip) 208 { 209 acpi_handle handle; 210 acpi_status status; 211 struct list_head *evt_pins; 212 struct acpi_gpio_evt_pin *evt_pin, *ep; 213 214 if (!chip->dev || !chip->to_irq) 215 return; 216 217 handle = ACPI_HANDLE(chip->dev); 218 if (!handle) 219 return; 220 221 status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins); 222 if (ACPI_FAILURE(status)) 223 return; 224 225 list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) { 226 devm_free_irq(chip->dev, evt_pin->irq, evt_pin); 227 list_del(&evt_pin->node); 228 kfree(evt_pin); 229 } 230 231 acpi_detach_data(handle, acpi_gpio_evt_dh); 232 kfree(evt_pins); 233 } 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(-ENOENT); 311 } 312 313 void acpi_gpiochip_add(struct gpio_chip *chip) 314 { 315 acpi_gpiochip_request_interrupts(chip); 316 } 317 318 void acpi_gpiochip_remove(struct gpio_chip *chip) 319 { 320 acpi_gpiochip_free_interrupts(chip); 321 } 322