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 #include <linux/mutex.h> 20 21 #include "gpiolib.h" 22 23 struct acpi_gpio_event { 24 struct list_head node; 25 acpi_handle handle; 26 unsigned int pin; 27 unsigned int irq; 28 }; 29 30 struct acpi_gpio_connection { 31 struct list_head node; 32 struct gpio_desc *desc; 33 }; 34 35 struct acpi_gpio_chip { 36 /* 37 * ACPICA requires that the first field of the context parameter 38 * passed to acpi_install_address_space_handler() is large enough 39 * to hold struct acpi_connection_info. 40 */ 41 struct acpi_connection_info conn_info; 42 struct list_head conns; 43 struct mutex conn_lock; 44 struct gpio_chip *chip; 45 struct list_head events; 46 }; 47 48 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data) 49 { 50 if (!gc->dev) 51 return false; 52 53 return ACPI_HANDLE(gc->dev) == data; 54 } 55 56 /** 57 * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API 58 * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1") 59 * @pin: ACPI GPIO pin number (0-based, controller-relative) 60 * 61 * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR 62 * error value 63 */ 64 65 static struct gpio_desc *acpi_get_gpiod(char *path, int pin) 66 { 67 struct gpio_chip *chip; 68 acpi_handle handle; 69 acpi_status status; 70 71 status = acpi_get_handle(NULL, path, &handle); 72 if (ACPI_FAILURE(status)) 73 return ERR_PTR(-ENODEV); 74 75 chip = gpiochip_find(handle, acpi_gpiochip_find); 76 if (!chip) 77 return ERR_PTR(-ENODEV); 78 79 if (pin < 0 || pin > chip->ngpio) 80 return ERR_PTR(-EINVAL); 81 82 return gpiochip_get_desc(chip, pin); 83 } 84 85 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data) 86 { 87 struct acpi_gpio_event *event = data; 88 89 acpi_evaluate_object(event->handle, NULL, NULL, NULL); 90 91 return IRQ_HANDLED; 92 } 93 94 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data) 95 { 96 struct acpi_gpio_event *event = data; 97 98 acpi_execute_simple_method(event->handle, NULL, event->pin); 99 100 return IRQ_HANDLED; 101 } 102 103 static void acpi_gpio_chip_dh(acpi_handle handle, void *data) 104 { 105 /* The address of this function is used as a key. */ 106 } 107 108 static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares, 109 void *context) 110 { 111 struct acpi_gpio_chip *acpi_gpio = context; 112 struct gpio_chip *chip = acpi_gpio->chip; 113 struct acpi_resource_gpio *agpio; 114 acpi_handle handle, evt_handle; 115 struct acpi_gpio_event *event; 116 irq_handler_t handler = NULL; 117 struct gpio_desc *desc; 118 unsigned long irqflags; 119 int ret, pin, irq; 120 121 if (ares->type != ACPI_RESOURCE_TYPE_GPIO) 122 return AE_OK; 123 124 agpio = &ares->data.gpio; 125 if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT) 126 return AE_OK; 127 128 handle = ACPI_HANDLE(chip->dev); 129 pin = agpio->pin_table[0]; 130 131 if (pin <= 255) { 132 char ev_name[5]; 133 sprintf(ev_name, "_%c%02X", 134 agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L', 135 pin); 136 if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle))) 137 handler = acpi_gpio_irq_handler; 138 } 139 if (!handler) { 140 if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle))) 141 handler = acpi_gpio_irq_handler_evt; 142 } 143 if (!handler) 144 return AE_BAD_PARAMETER; 145 146 desc = gpiochip_get_desc(chip, pin); 147 if (IS_ERR(desc)) { 148 dev_err(chip->dev, "Failed to get GPIO descriptor\n"); 149 return AE_ERROR; 150 } 151 152 ret = gpiochip_request_own_desc(desc, "ACPI:Event"); 153 if (ret) { 154 dev_err(chip->dev, "Failed to request GPIO\n"); 155 return AE_ERROR; 156 } 157 158 gpiod_direction_input(desc); 159 160 ret = gpiod_lock_as_irq(desc); 161 if (ret) { 162 dev_err(chip->dev, "Failed to lock GPIO as interrupt\n"); 163 goto fail_free_desc; 164 } 165 166 irq = gpiod_to_irq(desc); 167 if (irq < 0) { 168 dev_err(chip->dev, "Failed to translate GPIO to IRQ\n"); 169 goto fail_unlock_irq; 170 } 171 172 irqflags = IRQF_ONESHOT; 173 if (agpio->triggering == ACPI_LEVEL_SENSITIVE) { 174 if (agpio->polarity == ACPI_ACTIVE_HIGH) 175 irqflags |= IRQF_TRIGGER_HIGH; 176 else 177 irqflags |= IRQF_TRIGGER_LOW; 178 } else { 179 switch (agpio->polarity) { 180 case ACPI_ACTIVE_HIGH: 181 irqflags |= IRQF_TRIGGER_RISING; 182 break; 183 case ACPI_ACTIVE_LOW: 184 irqflags |= IRQF_TRIGGER_FALLING; 185 break; 186 default: 187 irqflags |= IRQF_TRIGGER_RISING | 188 IRQF_TRIGGER_FALLING; 189 break; 190 } 191 } 192 193 event = kzalloc(sizeof(*event), GFP_KERNEL); 194 if (!event) 195 goto fail_unlock_irq; 196 197 event->handle = evt_handle; 198 event->irq = irq; 199 event->pin = pin; 200 201 ret = request_threaded_irq(event->irq, NULL, handler, irqflags, 202 "ACPI:Event", event); 203 if (ret) { 204 dev_err(chip->dev, "Failed to setup interrupt handler for %d\n", 205 event->irq); 206 goto fail_free_event; 207 } 208 209 list_add_tail(&event->node, &acpi_gpio->events); 210 return AE_OK; 211 212 fail_free_event: 213 kfree(event); 214 fail_unlock_irq: 215 gpiod_unlock_as_irq(desc); 216 fail_free_desc: 217 gpiochip_free_own_desc(desc); 218 219 return AE_ERROR; 220 } 221 222 /** 223 * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events 224 * @acpi_gpio: ACPI GPIO chip 225 * 226 * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are 227 * handled by ACPI event methods which need to be called from the GPIO 228 * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which 229 * gpio pins have acpi event methods and assigns interrupt handlers that calls 230 * the acpi event methods for those pins. 231 */ 232 static void acpi_gpiochip_request_interrupts(struct acpi_gpio_chip *acpi_gpio) 233 { 234 struct gpio_chip *chip = acpi_gpio->chip; 235 236 if (!chip->dev || !chip->to_irq) 237 return; 238 239 INIT_LIST_HEAD(&acpi_gpio->events); 240 acpi_walk_resources(ACPI_HANDLE(chip->dev), "_AEI", 241 acpi_gpiochip_request_interrupt, acpi_gpio); 242 } 243 244 /** 245 * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts. 246 * @acpi_gpio: ACPI GPIO chip 247 * 248 * Free interrupts associated with GPIO ACPI event method for the given 249 * GPIO chip. 250 */ 251 static void acpi_gpiochip_free_interrupts(struct acpi_gpio_chip *acpi_gpio) 252 { 253 struct acpi_gpio_event *event, *ep; 254 struct gpio_chip *chip = acpi_gpio->chip; 255 256 if (!chip->dev || !chip->to_irq) 257 return; 258 259 list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) { 260 struct gpio_desc *desc; 261 262 free_irq(event->irq, event); 263 desc = gpiochip_get_desc(chip, event->pin); 264 if (WARN_ON(IS_ERR(desc))) 265 continue; 266 gpiod_unlock_as_irq(desc); 267 gpiochip_free_own_desc(desc); 268 list_del(&event->node); 269 kfree(event); 270 } 271 } 272 273 struct acpi_gpio_lookup { 274 struct acpi_gpio_info info; 275 int index; 276 struct gpio_desc *desc; 277 int n; 278 }; 279 280 static int acpi_find_gpio(struct acpi_resource *ares, void *data) 281 { 282 struct acpi_gpio_lookup *lookup = data; 283 284 if (ares->type != ACPI_RESOURCE_TYPE_GPIO) 285 return 1; 286 287 if (lookup->n++ == lookup->index && !lookup->desc) { 288 const struct acpi_resource_gpio *agpio = &ares->data.gpio; 289 290 lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr, 291 agpio->pin_table[0]); 292 lookup->info.gpioint = 293 agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT; 294 lookup->info.active_low = 295 agpio->polarity == ACPI_ACTIVE_LOW; 296 } 297 298 return 1; 299 } 300 301 /** 302 * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources 303 * @dev: pointer to a device to get GPIO from 304 * @index: index of GpioIo/GpioInt resource (starting from %0) 305 * @info: info pointer to fill in (optional) 306 * 307 * Function goes through ACPI resources for @dev and based on @index looks 308 * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor, 309 * and returns it. @index matches GpioIo/GpioInt resources only so if there 310 * are total %3 GPIO resources, the index goes from %0 to %2. 311 * 312 * If the GPIO cannot be translated or there is an error an ERR_PTR is 313 * returned. 314 * 315 * Note: if the GPIO resource has multiple entries in the pin list, this 316 * function only returns the first. 317 */ 318 struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index, 319 struct acpi_gpio_info *info) 320 { 321 struct acpi_gpio_lookup lookup; 322 struct list_head resource_list; 323 struct acpi_device *adev; 324 acpi_handle handle; 325 int ret; 326 327 if (!dev) 328 return ERR_PTR(-EINVAL); 329 330 handle = ACPI_HANDLE(dev); 331 if (!handle || acpi_bus_get_device(handle, &adev)) 332 return ERR_PTR(-ENODEV); 333 334 memset(&lookup, 0, sizeof(lookup)); 335 lookup.index = index; 336 337 INIT_LIST_HEAD(&resource_list); 338 ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio, 339 &lookup); 340 if (ret < 0) 341 return ERR_PTR(ret); 342 343 acpi_dev_free_resource_list(&resource_list); 344 345 if (lookup.desc && info) 346 *info = lookup.info; 347 348 return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT); 349 } 350 351 static acpi_status 352 acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address, 353 u32 bits, u64 *value, void *handler_context, 354 void *region_context) 355 { 356 struct acpi_gpio_chip *achip = region_context; 357 struct gpio_chip *chip = achip->chip; 358 struct acpi_resource_gpio *agpio; 359 struct acpi_resource *ares; 360 acpi_status status; 361 bool pull_up; 362 int i; 363 364 status = acpi_buffer_to_resource(achip->conn_info.connection, 365 achip->conn_info.length, &ares); 366 if (ACPI_FAILURE(status)) 367 return status; 368 369 if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) { 370 ACPI_FREE(ares); 371 return AE_BAD_PARAMETER; 372 } 373 374 agpio = &ares->data.gpio; 375 pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP; 376 377 if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT && 378 function == ACPI_WRITE)) { 379 ACPI_FREE(ares); 380 return AE_BAD_PARAMETER; 381 } 382 383 for (i = 0; i < agpio->pin_table_length; i++) { 384 unsigned pin = agpio->pin_table[i]; 385 struct acpi_gpio_connection *conn; 386 struct gpio_desc *desc; 387 bool found; 388 389 desc = gpiochip_get_desc(chip, pin); 390 if (IS_ERR(desc)) { 391 status = AE_ERROR; 392 goto out; 393 } 394 395 mutex_lock(&achip->conn_lock); 396 397 found = false; 398 list_for_each_entry(conn, &achip->conns, node) { 399 if (conn->desc == desc) { 400 found = true; 401 break; 402 } 403 } 404 if (!found) { 405 int ret; 406 407 ret = gpiochip_request_own_desc(desc, "ACPI:OpRegion"); 408 if (ret) { 409 status = AE_ERROR; 410 mutex_unlock(&achip->conn_lock); 411 goto out; 412 } 413 414 switch (agpio->io_restriction) { 415 case ACPI_IO_RESTRICT_INPUT: 416 gpiod_direction_input(desc); 417 break; 418 case ACPI_IO_RESTRICT_OUTPUT: 419 /* 420 * ACPI GPIO resources don't contain an 421 * initial value for the GPIO. Therefore we 422 * deduce that value from the pull field 423 * instead. If the pin is pulled up we 424 * assume default to be high, otherwise 425 * low. 426 */ 427 gpiod_direction_output(desc, pull_up); 428 break; 429 default: 430 /* 431 * Assume that the BIOS has configured the 432 * direction and pull accordingly. 433 */ 434 break; 435 } 436 437 conn = kzalloc(sizeof(*conn), GFP_KERNEL); 438 if (!conn) { 439 status = AE_NO_MEMORY; 440 gpiochip_free_own_desc(desc); 441 mutex_unlock(&achip->conn_lock); 442 goto out; 443 } 444 445 conn->desc = desc; 446 list_add_tail(&conn->node, &achip->conns); 447 } 448 449 mutex_unlock(&achip->conn_lock); 450 451 if (function == ACPI_WRITE) 452 gpiod_set_raw_value(desc, !!((1 << i) & *value)); 453 else 454 *value |= gpiod_get_raw_value(desc) << i; 455 } 456 457 out: 458 ACPI_FREE(ares); 459 return status; 460 } 461 462 static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip) 463 { 464 struct gpio_chip *chip = achip->chip; 465 acpi_handle handle = ACPI_HANDLE(chip->dev); 466 acpi_status status; 467 468 INIT_LIST_HEAD(&achip->conns); 469 mutex_init(&achip->conn_lock); 470 status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO, 471 acpi_gpio_adr_space_handler, 472 NULL, achip); 473 if (ACPI_FAILURE(status)) 474 dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n"); 475 } 476 477 static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip) 478 { 479 struct gpio_chip *chip = achip->chip; 480 acpi_handle handle = ACPI_HANDLE(chip->dev); 481 struct acpi_gpio_connection *conn, *tmp; 482 acpi_status status; 483 484 status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO, 485 acpi_gpio_adr_space_handler); 486 if (ACPI_FAILURE(status)) { 487 dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n"); 488 return; 489 } 490 491 list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) { 492 gpiochip_free_own_desc(conn->desc); 493 list_del(&conn->node); 494 kfree(conn); 495 } 496 } 497 498 void acpi_gpiochip_add(struct gpio_chip *chip) 499 { 500 struct acpi_gpio_chip *acpi_gpio; 501 acpi_handle handle; 502 acpi_status status; 503 504 handle = ACPI_HANDLE(chip->dev); 505 if (!handle) 506 return; 507 508 acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL); 509 if (!acpi_gpio) { 510 dev_err(chip->dev, 511 "Failed to allocate memory for ACPI GPIO chip\n"); 512 return; 513 } 514 515 acpi_gpio->chip = chip; 516 517 status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio); 518 if (ACPI_FAILURE(status)) { 519 dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n"); 520 kfree(acpi_gpio); 521 return; 522 } 523 524 acpi_gpiochip_request_interrupts(acpi_gpio); 525 acpi_gpiochip_request_regions(acpi_gpio); 526 } 527 528 void acpi_gpiochip_remove(struct gpio_chip *chip) 529 { 530 struct acpi_gpio_chip *acpi_gpio; 531 acpi_handle handle; 532 acpi_status status; 533 534 handle = ACPI_HANDLE(chip->dev); 535 if (!handle) 536 return; 537 538 status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio); 539 if (ACPI_FAILURE(status)) { 540 dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n"); 541 return; 542 } 543 544 acpi_gpiochip_free_regions(acpi_gpio); 545 acpi_gpiochip_free_interrupts(acpi_gpio); 546 547 acpi_detach_data(handle, acpi_gpio_chip_dh); 548 kfree(acpi_gpio); 549 } 550