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); 319