xref: /linux/drivers/gpio/gpiolib-acpi.c (revision 827634added7f38b7d724cab1dccdb2b004c13c3)
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/gpio/consumer.h>
16 #include <linux/gpio/driver.h>
17 #include <linux/export.h>
18 #include <linux/acpi.h>
19 #include <linux/interrupt.h>
20 #include <linux/mutex.h>
21 #include <linux/pinctrl/pinctrl.h>
22 
23 #include "gpiolib.h"
24 
25 struct acpi_gpio_event {
26 	struct list_head node;
27 	acpi_handle handle;
28 	unsigned int pin;
29 	unsigned int irq;
30 	struct gpio_desc *desc;
31 };
32 
33 struct acpi_gpio_connection {
34 	struct list_head node;
35 	unsigned int pin;
36 	struct gpio_desc *desc;
37 };
38 
39 struct acpi_gpio_chip {
40 	/*
41 	 * ACPICA requires that the first field of the context parameter
42 	 * passed to acpi_install_address_space_handler() is large enough
43 	 * to hold struct acpi_connection_info.
44 	 */
45 	struct acpi_connection_info conn_info;
46 	struct list_head conns;
47 	struct mutex conn_lock;
48 	struct gpio_chip *chip;
49 	struct list_head events;
50 };
51 
52 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
53 {
54 	if (!gc->dev)
55 		return false;
56 
57 	return ACPI_HANDLE(gc->dev) == data;
58 }
59 
60 #ifdef CONFIG_PINCTRL
61 /**
62  * acpi_gpiochip_pin_to_gpio_offset() - translates ACPI GPIO to Linux GPIO
63  * @chip: GPIO chip
64  * @pin: ACPI GPIO pin number from GpioIo/GpioInt resource
65  *
66  * Function takes ACPI GpioIo/GpioInt pin number as a parameter and
67  * translates it to a corresponding offset suitable to be passed to a
68  * GPIO controller driver.
69  *
70  * Typically the returned offset is same as @pin, but if the GPIO
71  * controller uses pin controller and the mapping is not contigous the
72  * offset might be different.
73  */
74 static int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip, int pin)
75 {
76 	struct gpio_pin_range *pin_range;
77 
78 	/* If there are no ranges in this chip, use 1:1 mapping */
79 	if (list_empty(&chip->pin_ranges))
80 		return pin;
81 
82 	list_for_each_entry(pin_range, &chip->pin_ranges, node) {
83 		const struct pinctrl_gpio_range *range = &pin_range->range;
84 		int i;
85 
86 		if (range->pins) {
87 			for (i = 0; i < range->npins; i++) {
88 				if (range->pins[i] == pin)
89 					return range->base + i - chip->base;
90 			}
91 		} else {
92 			if (pin >= range->pin_base &&
93 			    pin < range->pin_base + range->npins) {
94 				unsigned gpio_base;
95 
96 				gpio_base = range->base - chip->base;
97 				return gpio_base + pin - range->pin_base;
98 			}
99 		}
100 	}
101 
102 	return -EINVAL;
103 }
104 #else
105 static inline int acpi_gpiochip_pin_to_gpio_offset(struct gpio_chip *chip,
106 						   int pin)
107 {
108 	return pin;
109 }
110 #endif
111 
112 /**
113  * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
114  * @path:	ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
115  * @pin:	ACPI GPIO pin number (0-based, controller-relative)
116  *
117  * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
118  * error value
119  */
120 
121 static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
122 {
123 	struct gpio_chip *chip;
124 	acpi_handle handle;
125 	acpi_status status;
126 	int offset;
127 
128 	status = acpi_get_handle(NULL, path, &handle);
129 	if (ACPI_FAILURE(status))
130 		return ERR_PTR(-ENODEV);
131 
132 	chip = gpiochip_find(handle, acpi_gpiochip_find);
133 	if (!chip)
134 		return ERR_PTR(-ENODEV);
135 
136 	offset = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
137 	if (offset < 0)
138 		return ERR_PTR(offset);
139 
140 	return gpiochip_get_desc(chip, offset);
141 }
142 
143 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
144 {
145 	struct acpi_gpio_event *event = data;
146 
147 	acpi_evaluate_object(event->handle, NULL, NULL, NULL);
148 
149 	return IRQ_HANDLED;
150 }
151 
152 static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
153 {
154 	struct acpi_gpio_event *event = data;
155 
156 	acpi_execute_simple_method(event->handle, NULL, event->pin);
157 
158 	return IRQ_HANDLED;
159 }
160 
161 static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
162 {
163 	/* The address of this function is used as a key. */
164 }
165 
166 static acpi_status acpi_gpiochip_request_interrupt(struct acpi_resource *ares,
167 						   void *context)
168 {
169 	struct acpi_gpio_chip *acpi_gpio = context;
170 	struct gpio_chip *chip = acpi_gpio->chip;
171 	struct acpi_resource_gpio *agpio;
172 	acpi_handle handle, evt_handle;
173 	struct acpi_gpio_event *event;
174 	irq_handler_t handler = NULL;
175 	struct gpio_desc *desc;
176 	unsigned long irqflags;
177 	int ret, pin, irq;
178 
179 	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
180 		return AE_OK;
181 
182 	agpio = &ares->data.gpio;
183 	if (agpio->connection_type != ACPI_RESOURCE_GPIO_TYPE_INT)
184 		return AE_OK;
185 
186 	handle = ACPI_HANDLE(chip->dev);
187 	pin = agpio->pin_table[0];
188 
189 	if (pin <= 255) {
190 		char ev_name[5];
191 		sprintf(ev_name, "_%c%02X",
192 			agpio->triggering == ACPI_EDGE_SENSITIVE ? 'E' : 'L',
193 			pin);
194 		if (ACPI_SUCCESS(acpi_get_handle(handle, ev_name, &evt_handle)))
195 			handler = acpi_gpio_irq_handler;
196 	}
197 	if (!handler) {
198 		if (ACPI_SUCCESS(acpi_get_handle(handle, "_EVT", &evt_handle)))
199 			handler = acpi_gpio_irq_handler_evt;
200 	}
201 	if (!handler)
202 		return AE_BAD_PARAMETER;
203 
204 	pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
205 	if (pin < 0)
206 		return AE_BAD_PARAMETER;
207 
208 	desc = gpiochip_request_own_desc(chip, pin, "ACPI:Event");
209 	if (IS_ERR(desc)) {
210 		dev_err(chip->dev, "Failed to request GPIO\n");
211 		return AE_ERROR;
212 	}
213 
214 	gpiod_direction_input(desc);
215 
216 	ret = gpiochip_lock_as_irq(chip, pin);
217 	if (ret) {
218 		dev_err(chip->dev, "Failed to lock GPIO as interrupt\n");
219 		goto fail_free_desc;
220 	}
221 
222 	irq = gpiod_to_irq(desc);
223 	if (irq < 0) {
224 		dev_err(chip->dev, "Failed to translate GPIO to IRQ\n");
225 		goto fail_unlock_irq;
226 	}
227 
228 	irqflags = IRQF_ONESHOT;
229 	if (agpio->triggering == ACPI_LEVEL_SENSITIVE) {
230 		if (agpio->polarity == ACPI_ACTIVE_HIGH)
231 			irqflags |= IRQF_TRIGGER_HIGH;
232 		else
233 			irqflags |= IRQF_TRIGGER_LOW;
234 	} else {
235 		switch (agpio->polarity) {
236 		case ACPI_ACTIVE_HIGH:
237 			irqflags |= IRQF_TRIGGER_RISING;
238 			break;
239 		case ACPI_ACTIVE_LOW:
240 			irqflags |= IRQF_TRIGGER_FALLING;
241 			break;
242 		default:
243 			irqflags |= IRQF_TRIGGER_RISING |
244 				    IRQF_TRIGGER_FALLING;
245 			break;
246 		}
247 	}
248 
249 	event = kzalloc(sizeof(*event), GFP_KERNEL);
250 	if (!event)
251 		goto fail_unlock_irq;
252 
253 	event->handle = evt_handle;
254 	event->irq = irq;
255 	event->pin = pin;
256 	event->desc = desc;
257 
258 	ret = request_threaded_irq(event->irq, NULL, handler, irqflags,
259 				   "ACPI:Event", event);
260 	if (ret) {
261 		dev_err(chip->dev, "Failed to setup interrupt handler for %d\n",
262 			event->irq);
263 		goto fail_free_event;
264 	}
265 
266 	list_add_tail(&event->node, &acpi_gpio->events);
267 	return AE_OK;
268 
269 fail_free_event:
270 	kfree(event);
271 fail_unlock_irq:
272 	gpiochip_unlock_as_irq(chip, pin);
273 fail_free_desc:
274 	gpiochip_free_own_desc(desc);
275 
276 	return AE_ERROR;
277 }
278 
279 /**
280  * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
281  * @chip:      GPIO chip
282  *
283  * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
284  * handled by ACPI event methods which need to be called from the GPIO
285  * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
286  * gpio pins have acpi event methods and assigns interrupt handlers that calls
287  * the acpi event methods for those pins.
288  */
289 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
290 {
291 	struct acpi_gpio_chip *acpi_gpio;
292 	acpi_handle handle;
293 	acpi_status status;
294 
295 	if (!chip->dev || !chip->to_irq)
296 		return;
297 
298 	handle = ACPI_HANDLE(chip->dev);
299 	if (!handle)
300 		return;
301 
302 	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
303 	if (ACPI_FAILURE(status))
304 		return;
305 
306 	INIT_LIST_HEAD(&acpi_gpio->events);
307 	acpi_walk_resources(handle, "_AEI",
308 			    acpi_gpiochip_request_interrupt, acpi_gpio);
309 }
310 
311 /**
312  * acpi_gpiochip_free_interrupts() - Free GPIO ACPI event interrupts.
313  * @chip:      GPIO chip
314  *
315  * Free interrupts associated with GPIO ACPI event method for the given
316  * GPIO chip.
317  */
318 void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
319 {
320 	struct acpi_gpio_chip *acpi_gpio;
321 	struct acpi_gpio_event *event, *ep;
322 	acpi_handle handle;
323 	acpi_status status;
324 
325 	if (!chip->dev || !chip->to_irq)
326 		return;
327 
328 	handle = ACPI_HANDLE(chip->dev);
329 	if (!handle)
330 		return;
331 
332 	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
333 	if (ACPI_FAILURE(status))
334 		return;
335 
336 	list_for_each_entry_safe_reverse(event, ep, &acpi_gpio->events, node) {
337 		struct gpio_desc *desc;
338 
339 		free_irq(event->irq, event);
340 		desc = event->desc;
341 		if (WARN_ON(IS_ERR(desc)))
342 			continue;
343 		gpiochip_unlock_as_irq(chip, event->pin);
344 		gpiochip_free_own_desc(desc);
345 		list_del(&event->node);
346 		kfree(event);
347 	}
348 }
349 
350 int acpi_dev_add_driver_gpios(struct acpi_device *adev,
351 			      const struct acpi_gpio_mapping *gpios)
352 {
353 	if (adev && gpios) {
354 		adev->driver_gpios = gpios;
355 		return 0;
356 	}
357 	return -EINVAL;
358 }
359 EXPORT_SYMBOL_GPL(acpi_dev_add_driver_gpios);
360 
361 static bool acpi_get_driver_gpio_data(struct acpi_device *adev,
362 				      const char *name, int index,
363 				      struct acpi_reference_args *args)
364 {
365 	const struct acpi_gpio_mapping *gm;
366 
367 	if (!adev->driver_gpios)
368 		return false;
369 
370 	for (gm = adev->driver_gpios; gm->name; gm++)
371 		if (!strcmp(name, gm->name) && gm->data && index < gm->size) {
372 			const struct acpi_gpio_params *par = gm->data + index;
373 
374 			args->adev = adev;
375 			args->args[0] = par->crs_entry_index;
376 			args->args[1] = par->line_index;
377 			args->args[2] = par->active_low;
378 			args->nargs = 3;
379 			return true;
380 		}
381 
382 	return false;
383 }
384 
385 struct acpi_gpio_lookup {
386 	struct acpi_gpio_info info;
387 	int index;
388 	int pin_index;
389 	struct gpio_desc *desc;
390 	int n;
391 };
392 
393 static int acpi_find_gpio(struct acpi_resource *ares, void *data)
394 {
395 	struct acpi_gpio_lookup *lookup = data;
396 
397 	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
398 		return 1;
399 
400 	if (lookup->n++ == lookup->index && !lookup->desc) {
401 		const struct acpi_resource_gpio *agpio = &ares->data.gpio;
402 		int pin_index = lookup->pin_index;
403 
404 		if (pin_index >= agpio->pin_table_length)
405 			return 1;
406 
407 		lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
408 					      agpio->pin_table[pin_index]);
409 		lookup->info.gpioint =
410 			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
411 
412 		/*
413 		 * ActiveLow is only specified for GpioInt resource. If
414 		 * GpioIo is used then the only way to set the flag is
415 		 * to use _DSD "gpios" property.
416 		 */
417 		if (lookup->info.gpioint)
418 			lookup->info.active_low =
419 				agpio->polarity == ACPI_ACTIVE_LOW;
420 	}
421 
422 	return 1;
423 }
424 
425 /**
426  * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
427  * @adev: pointer to a ACPI device to get GPIO from
428  * @propname: Property name of the GPIO (optional)
429  * @index: index of GpioIo/GpioInt resource (starting from %0)
430  * @info: info pointer to fill in (optional)
431  *
432  * Function goes through ACPI resources for @adev and based on @index looks
433  * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
434  * and returns it. @index matches GpioIo/GpioInt resources only so if there
435  * are total %3 GPIO resources, the index goes from %0 to %2.
436  *
437  * If @propname is specified the GPIO is looked using device property. In
438  * that case @index is used to select the GPIO entry in the property value
439  * (in case of multiple).
440  *
441  * If the GPIO cannot be translated or there is an error an ERR_PTR is
442  * returned.
443  *
444  * Note: if the GPIO resource has multiple entries in the pin list, this
445  * function only returns the first.
446  */
447 struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
448 					  const char *propname, int index,
449 					  struct acpi_gpio_info *info)
450 {
451 	struct acpi_gpio_lookup lookup;
452 	struct list_head resource_list;
453 	bool active_low = false;
454 	int ret;
455 
456 	if (!adev)
457 		return ERR_PTR(-ENODEV);
458 
459 	memset(&lookup, 0, sizeof(lookup));
460 	lookup.index = index;
461 
462 	if (propname) {
463 		struct acpi_reference_args args;
464 
465 		dev_dbg(&adev->dev, "GPIO: looking up %s\n", propname);
466 
467 		memset(&args, 0, sizeof(args));
468 		ret = acpi_dev_get_property_reference(adev, propname,
469 						      index, &args);
470 		if (ret) {
471 			bool found = acpi_get_driver_gpio_data(adev, propname,
472 							       index, &args);
473 			if (!found)
474 				return ERR_PTR(ret);
475 		}
476 
477 		/*
478 		 * The property was found and resolved so need to
479 		 * lookup the GPIO based on returned args instead.
480 		 */
481 		adev = args.adev;
482 		if (args.nargs >= 2) {
483 			lookup.index = args.args[0];
484 			lookup.pin_index = args.args[1];
485 			/*
486 			 * 3rd argument, if present is used to
487 			 * specify active_low.
488 			 */
489 			if (args.nargs >= 3)
490 				active_low = !!args.args[2];
491 		}
492 
493 		dev_dbg(&adev->dev, "GPIO: _DSD returned %s %zd %llu %llu %llu\n",
494 			dev_name(&adev->dev), args.nargs,
495 			args.args[0], args.args[1], args.args[2]);
496 	} else {
497 		dev_dbg(&adev->dev, "GPIO: looking up %d in _CRS\n", index);
498 	}
499 
500 	INIT_LIST_HEAD(&resource_list);
501 	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
502 				     &lookup);
503 	if (ret < 0)
504 		return ERR_PTR(ret);
505 
506 	acpi_dev_free_resource_list(&resource_list);
507 
508 	if (lookup.desc && info) {
509 		*info = lookup.info;
510 		if (active_low)
511 			info->active_low = active_low;
512 	}
513 
514 	return lookup.desc ? lookup.desc : ERR_PTR(-ENOENT);
515 }
516 
517 static acpi_status
518 acpi_gpio_adr_space_handler(u32 function, acpi_physical_address address,
519 			    u32 bits, u64 *value, void *handler_context,
520 			    void *region_context)
521 {
522 	struct acpi_gpio_chip *achip = region_context;
523 	struct gpio_chip *chip = achip->chip;
524 	struct acpi_resource_gpio *agpio;
525 	struct acpi_resource *ares;
526 	int pin_index = (int)address;
527 	acpi_status status;
528 	bool pull_up;
529 	int length;
530 	int i;
531 
532 	status = acpi_buffer_to_resource(achip->conn_info.connection,
533 					 achip->conn_info.length, &ares);
534 	if (ACPI_FAILURE(status))
535 		return status;
536 
537 	if (WARN_ON(ares->type != ACPI_RESOURCE_TYPE_GPIO)) {
538 		ACPI_FREE(ares);
539 		return AE_BAD_PARAMETER;
540 	}
541 
542 	agpio = &ares->data.gpio;
543 	pull_up = agpio->pin_config == ACPI_PIN_CONFIG_PULLUP;
544 
545 	if (WARN_ON(agpio->io_restriction == ACPI_IO_RESTRICT_INPUT &&
546 	    function == ACPI_WRITE)) {
547 		ACPI_FREE(ares);
548 		return AE_BAD_PARAMETER;
549 	}
550 
551 	length = min(agpio->pin_table_length, (u16)(pin_index + bits));
552 	for (i = pin_index; i < length; ++i) {
553 		unsigned pin = agpio->pin_table[i];
554 		struct acpi_gpio_connection *conn;
555 		struct gpio_desc *desc;
556 		bool found;
557 
558 		pin = acpi_gpiochip_pin_to_gpio_offset(chip, pin);
559 		if (pin < 0) {
560 			status = AE_BAD_PARAMETER;
561 			goto out;
562 		}
563 
564 		mutex_lock(&achip->conn_lock);
565 
566 		found = false;
567 		list_for_each_entry(conn, &achip->conns, node) {
568 			if (conn->pin == pin) {
569 				found = true;
570 				desc = conn->desc;
571 				break;
572 			}
573 		}
574 		if (!found) {
575 			desc = gpiochip_request_own_desc(chip, pin,
576 							 "ACPI:OpRegion");
577 			if (IS_ERR(desc)) {
578 				status = AE_ERROR;
579 				mutex_unlock(&achip->conn_lock);
580 				goto out;
581 			}
582 
583 			switch (agpio->io_restriction) {
584 			case ACPI_IO_RESTRICT_INPUT:
585 				gpiod_direction_input(desc);
586 				break;
587 			case ACPI_IO_RESTRICT_OUTPUT:
588 				/*
589 				 * ACPI GPIO resources don't contain an
590 				 * initial value for the GPIO. Therefore we
591 				 * deduce that value from the pull field
592 				 * instead. If the pin is pulled up we
593 				 * assume default to be high, otherwise
594 				 * low.
595 				 */
596 				gpiod_direction_output(desc, pull_up);
597 				break;
598 			default:
599 				/*
600 				 * Assume that the BIOS has configured the
601 				 * direction and pull accordingly.
602 				 */
603 				break;
604 			}
605 
606 			conn = kzalloc(sizeof(*conn), GFP_KERNEL);
607 			if (!conn) {
608 				status = AE_NO_MEMORY;
609 				gpiochip_free_own_desc(desc);
610 				mutex_unlock(&achip->conn_lock);
611 				goto out;
612 			}
613 
614 			conn->pin = pin;
615 			conn->desc = desc;
616 			list_add_tail(&conn->node, &achip->conns);
617 		}
618 
619 		mutex_unlock(&achip->conn_lock);
620 
621 		if (function == ACPI_WRITE)
622 			gpiod_set_raw_value_cansleep(desc,
623 						     !!((1 << i) & *value));
624 		else
625 			*value |= (u64)gpiod_get_raw_value_cansleep(desc) << i;
626 	}
627 
628 out:
629 	ACPI_FREE(ares);
630 	return status;
631 }
632 
633 static void acpi_gpiochip_request_regions(struct acpi_gpio_chip *achip)
634 {
635 	struct gpio_chip *chip = achip->chip;
636 	acpi_handle handle = ACPI_HANDLE(chip->dev);
637 	acpi_status status;
638 
639 	INIT_LIST_HEAD(&achip->conns);
640 	mutex_init(&achip->conn_lock);
641 	status = acpi_install_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
642 						    acpi_gpio_adr_space_handler,
643 						    NULL, achip);
644 	if (ACPI_FAILURE(status))
645 		dev_err(chip->dev, "Failed to install GPIO OpRegion handler\n");
646 }
647 
648 static void acpi_gpiochip_free_regions(struct acpi_gpio_chip *achip)
649 {
650 	struct gpio_chip *chip = achip->chip;
651 	acpi_handle handle = ACPI_HANDLE(chip->dev);
652 	struct acpi_gpio_connection *conn, *tmp;
653 	acpi_status status;
654 
655 	status = acpi_remove_address_space_handler(handle, ACPI_ADR_SPACE_GPIO,
656 						   acpi_gpio_adr_space_handler);
657 	if (ACPI_FAILURE(status)) {
658 		dev_err(chip->dev, "Failed to remove GPIO OpRegion handler\n");
659 		return;
660 	}
661 
662 	list_for_each_entry_safe_reverse(conn, tmp, &achip->conns, node) {
663 		gpiochip_free_own_desc(conn->desc);
664 		list_del(&conn->node);
665 		kfree(conn);
666 	}
667 }
668 
669 void acpi_gpiochip_add(struct gpio_chip *chip)
670 {
671 	struct acpi_gpio_chip *acpi_gpio;
672 	acpi_handle handle;
673 	acpi_status status;
674 
675 	if (!chip || !chip->dev)
676 		return;
677 
678 	handle = ACPI_HANDLE(chip->dev);
679 	if (!handle)
680 		return;
681 
682 	acpi_gpio = kzalloc(sizeof(*acpi_gpio), GFP_KERNEL);
683 	if (!acpi_gpio) {
684 		dev_err(chip->dev,
685 			"Failed to allocate memory for ACPI GPIO chip\n");
686 		return;
687 	}
688 
689 	acpi_gpio->chip = chip;
690 
691 	status = acpi_attach_data(handle, acpi_gpio_chip_dh, acpi_gpio);
692 	if (ACPI_FAILURE(status)) {
693 		dev_err(chip->dev, "Failed to attach ACPI GPIO chip\n");
694 		kfree(acpi_gpio);
695 		return;
696 	}
697 
698 	acpi_gpiochip_request_regions(acpi_gpio);
699 }
700 
701 void acpi_gpiochip_remove(struct gpio_chip *chip)
702 {
703 	struct acpi_gpio_chip *acpi_gpio;
704 	acpi_handle handle;
705 	acpi_status status;
706 
707 	if (!chip || !chip->dev)
708 		return;
709 
710 	handle = ACPI_HANDLE(chip->dev);
711 	if (!handle)
712 		return;
713 
714 	status = acpi_get_data(handle, acpi_gpio_chip_dh, (void **)&acpi_gpio);
715 	if (ACPI_FAILURE(status)) {
716 		dev_warn(chip->dev, "Failed to retrieve ACPI GPIO chip\n");
717 		return;
718 	}
719 
720 	acpi_gpiochip_free_regions(acpi_gpio);
721 
722 	acpi_detach_data(handle, acpi_gpio_chip_dh);
723 	kfree(acpi_gpio);
724 }
725 
726 static unsigned int acpi_gpio_package_count(const union acpi_object *obj)
727 {
728 	const union acpi_object *element = obj->package.elements;
729 	const union acpi_object *end = element + obj->package.count;
730 	unsigned int count = 0;
731 
732 	while (element < end) {
733 		if (element->type == ACPI_TYPE_LOCAL_REFERENCE)
734 			count++;
735 
736 		element++;
737 	}
738 	return count;
739 }
740 
741 static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
742 {
743 	unsigned int *count = data;
744 
745 	if (ares->type == ACPI_RESOURCE_TYPE_GPIO)
746 		*count += ares->data.gpio.pin_table_length;
747 
748 	return 1;
749 }
750 
751 /**
752  * acpi_gpio_count - return the number of GPIOs associated with a
753  *		device / function or -ENOENT if no GPIO has been
754  *		assigned to the requested function.
755  * @dev:	GPIO consumer, can be NULL for system-global GPIOs
756  * @con_id:	function within the GPIO consumer
757  */
758 int acpi_gpio_count(struct device *dev, const char *con_id)
759 {
760 	struct acpi_device *adev = ACPI_COMPANION(dev);
761 	const union acpi_object *obj;
762 	const struct acpi_gpio_mapping *gm;
763 	int count = -ENOENT;
764 	int ret;
765 	char propname[32];
766 	unsigned int i;
767 
768 	/* Try first from _DSD */
769 	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
770 		if (con_id && strcmp(con_id, "gpios"))
771 			snprintf(propname, sizeof(propname), "%s-%s",
772 				 con_id, gpio_suffixes[i]);
773 		else
774 			snprintf(propname, sizeof(propname), "%s",
775 				 gpio_suffixes[i]);
776 
777 		ret = acpi_dev_get_property(adev, propname, ACPI_TYPE_ANY,
778 					    &obj);
779 		if (ret == 0) {
780 			if (obj->type == ACPI_TYPE_LOCAL_REFERENCE)
781 				count = 1;
782 			else if (obj->type == ACPI_TYPE_PACKAGE)
783 				count = acpi_gpio_package_count(obj);
784 		} else if (adev->driver_gpios) {
785 			for (gm = adev->driver_gpios; gm->name; gm++)
786 				if (strcmp(propname, gm->name) == 0) {
787 					count = gm->size;
788 					break;
789 				}
790 		}
791 		if (count >= 0)
792 			break;
793 	}
794 
795 	/* Then from plain _CRS GPIOs */
796 	if (count < 0) {
797 		struct list_head resource_list;
798 		unsigned int crs_count = 0;
799 
800 		INIT_LIST_HEAD(&resource_list);
801 		acpi_dev_get_resources(adev, &resource_list,
802 				       acpi_find_gpio_count, &crs_count);
803 		acpi_dev_free_resource_list(&resource_list);
804 		if (crs_count > 0)
805 			count = crs_count;
806 	}
807 	return count;
808 }
809