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/*
* 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);
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