summaryrefslogtreecommitdiffstats
path: root/drivers/gpio/gpiolib-acpi.c
blob: a063eb04b6ce9dd8c36d45d98d743db2691c989d (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
/*
 * 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.h>
#include <linux/export.h>
#include <linux/acpi_gpio.h>
#include <linux/acpi.h>
#include <linux/interrupt.h>

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

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

/**
 * acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number 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 number to use with Linux generic GPIO API, or errno error value
 */

int acpi_get_gpio(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 -ENODEV;

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

	if (!gpio_is_valid(chip->base + pin))
		return -EINVAL;

	return chip->base + pin;
}
EXPORT_SYMBOL_GPL(acpi_get_gpio);


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;
}

/**
 * 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.
 *
 * Interrupts are automatically freed on driver detach
 */

void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
{
	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
	struct acpi_resource *res;
	acpi_handle handle, ev_handle;
	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;

	/* If a gpio interrupt has an acpi event handler method, then
	 * 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)) {

		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;

		sprintf(ev_name, "_%c%02X",
		res->data.gpio.triggering ? 'E' : 'L', pin);

		status = acpi_get_handle(handle, ev_name, &ev_handle);
		if (ACPI_FAILURE(status))
			continue;

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

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