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55 lines
1.3 KiB
C
55 lines
1.3 KiB
C
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/*
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* ACPI helpers for GPIO API
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*
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* Copyright (C) 2012, Intel Corporation
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* Authors: Mathias Nyman <mathias.nyman@linux.intel.com>
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* Mika Westerberg <mika.westerberg@linux.intel.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/errno.h>
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#include <linux/gpio.h>
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#include <linux/export.h>
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#include <linux/acpi_gpio.h>
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#include <linux/acpi.h>
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static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
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{
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if (!gc->dev)
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return false;
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return ACPI_HANDLE(gc->dev) == data;
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}
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/**
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* acpi_get_gpio() - Translate ACPI GPIO pin to GPIO number usable with GPIO API
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* @path: ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
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* @pin: ACPI GPIO pin number (0-based, controller-relative)
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*
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* Returns GPIO number to use with Linux generic GPIO API, or errno error value
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*/
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int acpi_get_gpio(char *path, int pin)
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{
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struct gpio_chip *chip;
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acpi_handle handle;
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acpi_status status;
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status = acpi_get_handle(NULL, path, &handle);
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if (ACPI_FAILURE(status))
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return -ENODEV;
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chip = gpiochip_find(handle, acpi_gpiochip_find);
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if (!chip)
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return -ENODEV;
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if (!gpio_is_valid(chip->base + pin))
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return -EINVAL;
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return chip->base + pin;
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}
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EXPORT_SYMBOL_GPL(acpi_get_gpio);
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