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Mathias Nymane29482e2012-11-30 12:37:36 +01001/*
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/export.h>
16#include <linux/acpi_gpio.h>
17#include <linux/acpi.h>
Mathias Nyman0d1c28a2013-01-28 16:23:10 +020018#include <linux/interrupt.h>
Mathias Nymane29482e2012-11-30 12:37:36 +010019
20static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
21{
22 if (!gc->dev)
23 return false;
24
25 return ACPI_HANDLE(gc->dev) == data;
26}
27
28/**
29 * acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API
30 * @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
31 * @pin: ACPI GPIO pin number (0-based, controller-relative)
32 *
33 * Returns GPIO number to use with Linux generic GPIO API, or errno error value
34 */
35
36int acpi_get_gpio(char *path, int pin)
37{
38 struct gpio_chip *chip;
39 acpi_handle handle;
40 acpi_status status;
41
42 status = acpi_get_handle(NULL, path, &handle);
43 if (ACPI_FAILURE(status))
44 return -ENODEV;
45
46 chip = gpiochip_find(handle, acpi_gpiochip_find);
47 if (!chip)
48 return -ENODEV;
49
50 if (!gpio_is_valid(chip->base + pin))
51 return -EINVAL;
52
53 return chip->base + pin;
54}
55EXPORT_SYMBOL_GPL(acpi_get_gpio);
Mathias Nyman0d1c28a2013-01-28 16:23:10 +020056
57
58static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
59{
60 acpi_handle handle = data;
61
62 acpi_evaluate_object(handle, NULL, NULL, NULL);
63
64 return IRQ_HANDLED;
65}
66
67/**
68 * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
69 * @chip: gpio chip
70 *
71 * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
72 * handled by ACPI event methods which need to be called from the GPIO
73 * chip's interrupt handler. acpi_gpiochip_request_interrupts finds out which
74 * gpio pins have acpi event methods and assigns interrupt handlers that calls
75 * the acpi event methods for those pins.
76 *
77 * Interrupts are automatically freed on driver detach
78 */
79
80void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
81{
82 struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
83 struct acpi_resource *res;
84 acpi_handle handle, ev_handle;
85 acpi_status status;
Mathias Nyman1107ca12013-02-04 11:32:22 +020086 unsigned int pin;
87 int irq, ret;
Mathias Nyman0d1c28a2013-01-28 16:23:10 +020088 char ev_name[5];
89
90 if (!chip->dev || !chip->to_irq)
91 return;
92
93 handle = ACPI_HANDLE(chip->dev);
94 if (!handle)
95 return;
96
97 status = acpi_get_event_resources(handle, &buf);
98 if (ACPI_FAILURE(status))
99 return;
100
101 /* If a gpio interrupt has an acpi event handler method, then
102 * set up an interrupt handler that calls the acpi event handler
103 */
104
105 for (res = buf.pointer;
106 res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
107 res = ACPI_NEXT_RESOURCE(res)) {
108
109 if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
110 res->data.gpio.connection_type !=
111 ACPI_RESOURCE_GPIO_TYPE_INT)
112 continue;
113
114 pin = res->data.gpio.pin_table[0];
115 if (pin > chip->ngpio)
116 continue;
117
118 sprintf(ev_name, "_%c%02X",
119 res->data.gpio.triggering ? 'E' : 'L', pin);
120
121 status = acpi_get_handle(handle, ev_name, &ev_handle);
122 if (ACPI_FAILURE(status))
123 continue;
124
125 irq = chip->to_irq(chip, pin);
126 if (irq < 0)
127 continue;
128
129 /* Assume BIOS sets the triggering, so no flags */
Mathias Nyman1107ca12013-02-04 11:32:22 +0200130 ret = devm_request_threaded_irq(chip->dev, irq, NULL,
Mathias Nyman0d1c28a2013-01-28 16:23:10 +0200131 acpi_gpio_irq_handler,
132 0,
133 "GPIO-signaled-ACPI-event",
134 ev_handle);
Mathias Nyman1107ca12013-02-04 11:32:22 +0200135 if (ret)
136 dev_err(chip->dev,
137 "Failed to request IRQ %d ACPI event handler\n",
138 irq);
Mathias Nyman0d1c28a2013-01-28 16:23:10 +0200139 }
140}
141EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);