linux/drivers/gpio/gpiolib-acpi.c
Mathias Nyman e29482e848 gpio / ACPI: add ACPI support
Add support for translating ACPI GPIO pin numbers to Linux GPIO API pins.
Needs a gpio controller driver with the acpi handler hook set.

Drivers can use acpi_get_gpio() to translate ACPI5 GpioIO and GpioInt
resources to Linux GPIO's.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2012-11-30 12:37:36 +01:00

55 lines
1.3 KiB
C

/*
* 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>
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);