2 * ACPI helpers for GPIO API
4 * Copyright (C) 2012, Intel Corporation
5 * Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
6 * Mika Westerberg <mika.westerberg@linux.intel.com>
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.
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>
18 #include <linux/interrupt.h>
20 static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
25 return ACPI_HANDLE(gc->dev) == data;
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)
33 * Returns GPIO number to use with Linux generic GPIO API, or errno error value
36 int acpi_get_gpio(char *path, int pin)
38 struct gpio_chip *chip;
42 status = acpi_get_handle(NULL, path, &handle);
43 if (ACPI_FAILURE(status))
46 chip = gpiochip_find(handle, acpi_gpiochip_find);
50 if (!gpio_is_valid(chip->base + pin))
53 return chip->base + pin;
55 EXPORT_SYMBOL_GPL(acpi_get_gpio);
58 static irqreturn_t acpi_gpio_irq_handler(int irq, void *data)
60 acpi_handle handle = data;
62 acpi_evaluate_object(handle, NULL, NULL, NULL);
68 * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
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.
77 * Interrupts are automatically freed on driver detach
80 void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
82 struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
83 struct acpi_resource *res;
84 acpi_handle handle, ev_handle;
90 if (!chip->dev || !chip->to_irq)
93 handle = ACPI_HANDLE(chip->dev);
97 status = acpi_get_event_resources(handle, &buf);
98 if (ACPI_FAILURE(status))
101 /* If a gpio interrupt has an acpi event handler method, then
102 * set up an interrupt handler that calls the acpi event handler
105 for (res = buf.pointer;
106 res && (res->type != ACPI_RESOURCE_TYPE_END_TAG);
107 res = ACPI_NEXT_RESOURCE(res)) {
109 if (res->type != ACPI_RESOURCE_TYPE_GPIO ||
110 res->data.gpio.connection_type !=
111 ACPI_RESOURCE_GPIO_TYPE_INT)
114 pin = res->data.gpio.pin_table[0];
115 if (pin > chip->ngpio)
118 sprintf(ev_name, "_%c%02X",
119 res->data.gpio.triggering ? 'E' : 'L', pin);
121 status = acpi_get_handle(handle, ev_name, &ev_handle);
122 if (ACPI_FAILURE(status))
125 irq = chip->to_irq(chip, pin);
129 /* Assume BIOS sets the triggering, so no flags */
130 ret = devm_request_threaded_irq(chip->dev, irq, NULL,
131 acpi_gpio_irq_handler,
133 "GPIO-signaled-ACPI-event",
137 "Failed to request IRQ %d ACPI event handler\n",
141 EXPORT_SYMBOL(acpi_gpiochip_request_interrupts);