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); 313