summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpiolib-acpi.c
blob: ae0ffdce8bd57d4857b46cdc963f708923839982 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
/*
 * ACPI helpers for GPIO API
 *
 * Copyright (C) 2012, Intel Corporation
 * Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
 *          Mika Westerberg <mika.westerberg@linux.intel.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/errno.h>
#include <linux/gpio/consumer.h>
#include <linux/export.h>
#include <linux/acpi_gpio.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>

struct acpi_gpio_evt_pin {
	struct list_head node;
	acpi_handle *evt_handle;
	unsigned int pin;
	unsigned int irq;
};

static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
{
	if (!gc->dev)
		return false;

	return ACPI_HANDLE(gc->dev) == data;
}

/**
 * acpi_get_gpiod() - Translate ACPI GPIO pin to GPIO descriptor usable with GPIO API
 * @path:	ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
 * @pin:	ACPI GPIO pin number (0-based, controller-relative)
 *
 * Returns GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
 * error value
 */

static struct gpio_desc *acpi_get_gpiod(char *path, int pin)
{
	struct gpio_chip *chip;
	acpi_handle handle;
	acpi_status status;

	status = acpi_get_handle(NULL, path, &handle);
	if (ACPI_FAILURE(status))
		return ERR_PTR(-ENODEV);

	chip = gpiochip_find(handle, acpi_gpiochip_find);
	if (!chip)
		return ERR_PTR(-ENODEV);

	if (pin < 0 || pin > chip->ngpio)
		return ERR_PTR(-EINVAL);

	return gpio_to_desc(chip->base + pin);
}

static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
{
	acpi_handle handle = data;

	acpi_evaluate_object(handle, NULL, NULL, NULL);

	return IRQ_HANDLED;
}

static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
{
	struct acpi_gpio_evt_pin *evt_pin = data;

	acpi_execute_simple_method(evt_pin->evt_handle, NULL, evt_pin->pin);

	return IRQ_HANDLED;
}

static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
{
	/* The address of this function is used as a key. */
}

/**
 * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
 * @chip:      gpio chip
 *
 * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
 * handled by ACPI event methods which need to be called from the GPIO
 * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
 * gpio pins have acpi event methods and assigns interrupt handlers that calls
 * the acpi event methods for those pins.
 */
void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
{
	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
	struct acpi_resource *res;
	acpi_handle handle, evt_handle;
	struct list_head *evt_pins = NULL;
	acpi_status status;
	unsigned int pin;
	int irq, ret;
	char ev_name[5];

	if (!chip->dev || !chip->to_irq)
		return;

	handle = ACPI_HANDLE(chip->dev);
	if (!handle)
		return;

	status = acpi_get_event_resources(handle, &buf);
	if (ACPI_FAILURE(status))
		return;

	status = acpi_get_handle(handle, "_EVT", &evt_handle);
	if (ACPI_SUCCESS(status)) {
		evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
		if (evt_pins) {
			INIT_LIST_HEAD(evt_pins);
			status = acpi_attach_data(handle, acpi_gpio_evt_dh,
						  evt_pins);
			if (ACPI_FAILURE(status)) {
				kfree(evt_pins);
				evt_pins = NULL;
			}
		}
	}

	/*
	 * If a GPIO interrupt has an ACPI event handler method, or _EVT is
	 * present, set up an interrupt handler that calls the ACPI event
	 * handler.
	 */
	for (res = buf.pointer;
	     res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
	     res = ACPI_NEXT_RESOURCE(res)) {
		irq_handler_t handler = NULL;
		void *data;

		if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
		    res->data.gpio.connection_type !=
		    ACPI_RESOURCE_GPIO_TYPE_INT)
			continue;

		pin = res->data.gpio.pin_table[0];
		if (pin > chip->ngpio)
			continue;

		irq = chip->to_irq(chip, pin);
		if (irq < 0)
			continue;

		if (pin <= 255) {
			acpi_handle ev_handle;

			sprintf(ev_name, "_%c%02X",
				res->data.gpio.triggering ? 'E' : 'L', pin);
			status = acpi_get_handle(handle, ev_name, &ev_handle);
			if (ACPI_SUCCESS(status)) {
				handler = acpi_gpio_irq_handler;
				data = ev_handle;
			}
		}
		if (!handler && evt_pins) {
			struct acpi_gpio_evt_pin *evt_pin;

			evt_pin = kzalloc(sizeof(*evt_pin), GFP_KERNEL);
			if (!evt_pin)
				continue;

			list_add_tail(&evt_pin->node, evt_pins);
			evt_pin->evt_handle = evt_handle;
			evt_pin->pin = pin;
			evt_pin->irq = irq;
			handler = acpi_gpio_irq_handler_evt;
			data = evt_pin;
		}
		if (!handler)
			continue;

		/* Assume BIOS sets the triggering, so no flags */
		ret = devm_request_threaded_irq(chip->dev, irq, NULL, handler,
						0, "GPIO-signaled-ACPI-event",
						data);
		if (ret)
			dev_err(chip->dev,
				"Failed to request IRQ %d ACPI event handler\n",
				irq);
	}
}
EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);

/**
 * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
 * @chip:      gpio chip
 *
 * Free interrupts associated with the _EVT method for the given GPIO chip.
 *
 * The remaining ACPI event interrupts associated with the chip are freed
 * automatically.
 */
void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
{
	acpi_handle handle;
	acpi_status status;
	struct list_head *evt_pins;
	struct acpi_gpio_evt_pin *evt_pin, *ep;

	if (!chip->dev || !chip->to_irq)
		return;

	handle = ACPI_HANDLE(chip->dev);
	if (!handle)
		return;

	status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
	if (ACPI_FAILURE(status))
		return;

	list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
		devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
		list_del(&evt_pin->node);
		kfree(evt_pin);
	}

	acpi_detach_data(handle, acpi_gpio_evt_dh);
	kfree(evt_pins);
}
EXPORT_SYMBOL(acpi_gpiochip_free_interrupts);

struct acpi_gpio_lookup {
	struct acpi_gpio_info info;
	int index;
	struct gpio_desc *desc;
	int n;
};

static int acpi_find_gpio(struct acpi_resource *ares, void *data)
{
	struct acpi_gpio_lookup *lookup = data;

	if (ares->type != ACPI_RESOURCE_TYPE_GPIO)
		return 1;

	if (lookup->n++ == lookup->index && !lookup->desc) {
		const struct acpi_resource_gpio *agpio = &ares->data.gpio;

		lookup->desc = acpi_get_gpiod(agpio->resource_source.string_ptr,
					      agpio->pin_table[0]);
		lookup->info.gpioint =
			agpio->connection_type == ACPI_RESOURCE_GPIO_TYPE_INT;
		lookup->info.active_low =
			agpio->polarity == ACPI_ACTIVE_LOW;
	}

	return 1;
}

/**
 * acpi_get_gpiod_by_index() - get a GPIO descriptor from device resources
 * @dev: pointer to a device to get GPIO from
 * @index: index of GpioIo/GpioInt resource (starting from %0)
 * @info: info pointer to fill in (optional)
 *
 * Function goes through ACPI resources for @dev and based on @index looks
 * up a GpioIo/GpioInt resource, translates it to the Linux GPIO descriptor,
 * and returns it. @index matches GpioIo/GpioInt resources only so if there
 * are total %3 GPIO resources, the index goes from %0 to %2.
 *
 * If the GPIO cannot be translated or there is an error an ERR_PTR is
 * returned.
 *
 * Note: if the GPIO resource has multiple entries in the pin list, this
 * function only returns the first.
 */
struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
					  struct acpi_gpio_info *info)
{
	struct acpi_gpio_lookup lookup;
	struct list_head resource_list;
	struct acpi_device *adev;
	acpi_handle handle;
	int ret;

	if (!dev)
		return ERR_PTR(-EINVAL);

	handle = ACPI_HANDLE(dev);
	if (!handle || acpi_bus_get_device(handle, &adev))
		return ERR_PTR(-ENODEV);

	memset(&lookup, 0, sizeof(lookup));
	lookup.index = index;

	INIT_LIST_HEAD(&resource_list);
	ret = acpi_dev_get_resources(adev, &resource_list, acpi_find_gpio,
				     &lookup);
	if (ret < 0)
		return ERR_PTR(ret);

	acpi_dev_free_resource_list(&resource_list);

	if (lookup.desc && info)
		*info = lookup.info;

	return lookup.desc ? lookup.desc : ERR_PTR(-ENODEV);
}
EXPORT_SYMBOL_GPL(acpi_get_gpiod_by_index);