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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
23struct acpi_gpio_event {
24 struct list_head node;
25 acpi_handle handle;
26 unsigned int pin;
27 unsigned int irq;
28};
29
30struct acpi_gpio_connection {
31 struct list_head node;
32 struct gpio_desc *desc;
33};
34
35struct 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
48static 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
65static 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
85static 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
94static 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
103static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
104{
105 /* The address of this function is used as a key. */
106}
107
108static 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
212fail_free_event:
213 kfree(event);
214fail_unlock_irq:
215 gpiod_unlock_as_irq(desc);
216fail_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 */
232static void acpi_gpiochip_request_interrupts(struct acpi_gpio_chip *acpi_gpio)
233{
234 struct gpio_chip *chip = acpi_gpio->chip;
235
236 if (!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 */
251static 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->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
273struct acpi_gpio_lookup {
274 struct acpi_gpio_info info;
275 int index;
276 struct gpio_desc *desc;
277 int n;
278};
279
280static 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 */
318struct 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
351static acpi_status
352acpi_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 |= (u64)gpiod_get_raw_value(desc) << i;
455 }
456
457out:
458 ACPI_FREE(ares);
459 return status;
460}
461
462static 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
477static 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
498void 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 if (!chip || !chip->dev)
505 return;
506
507 handle = ACPI_HANDLE(chip->dev);
508 if (!handle)
509 return;
510
511 acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
512 if (!acpi_gpio) {
513 dev_err(chip->dev,
514 "Failed to allocate memory for ACPI GPIO chip\n");
515 return;
516 }
517
518 acpi_gpio->chip = chip;
519
520 status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
521 if (ACPI_FAILURE(status)) {
522 dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
523 kfree(acpi_gpio);
524 return;
525 }
526
527 acpi_gpiochip_request_interrupts(acpi_gpio);
528 acpi_gpiochip_request_regions(acpi_gpio);
529}
530
531void acpi_gpiochip_remove(struct gpio_chip *chip)
532{
533 struct acpi_gpio_chip *acpi_gpio;
534 acpi_handle handle;
535 acpi_status status;
536
537 if (!chip || !chip->dev)
538 return;
539
540 handle = ACPI_HANDLE(chip->dev);
541 if (!handle)
542 return;
543
544 status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
545 if (ACPI_FAILURE(status)) {
546 dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
547 return;
548 }
549
550 acpi_gpiochip_free_regions(acpi_gpio);
551 acpi_gpiochip_free_interrupts(acpi_gpio);
552
553 acpi_detach_data(handle, acpi_gpio_chip_dh);
554 kfree(acpi_gpio);
555}