devres.c

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/*
 * drivers/gpio/devres.c - managed gpio resources
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * This file is based on kernel/irq/devres.c
 *
 * Copyright (c) 2011 John Crispin <[email protected]>
 */

#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/device.h>
#include <linux/gfp.h>

static void devm_gpio_release(struct device *dev, void *res)
{
    unsigned *gpio = res;

    gpio_free(*gpio);
}

static int devm_gpio_match(struct device *dev, void *res, void *data)
{
    unsigned *this = res, *gpio = data;

    return *this == *gpio;
}

int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
{
    unsigned *dr;
    int rc;

    dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
    if (!dr)
        return -ENOMEM;

    rc = gpio_request(gpio, label);
    if (rc) {
        devres_free(dr);
        return rc;
    }

    *dr = gpio;
    devres_add(dev, dr);

    return 0;
}
EXPORT_SYMBOL(devm_gpio_request);

int devm_gpio_request_one(struct device *dev, unsigned gpio,
              unsigned long flags, const char *label)
{
    unsigned *dr;
    int rc;

    dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
    if (!dr)
        return -ENOMEM;

    rc = gpio_request_one(gpio, flags, label);
    if (rc) {
        devres_free(dr);
        return rc;
    }

    *dr = gpio;
    devres_add(dev, dr);

    return 0;
}
EXPORT_SYMBOL(devm_gpio_request_one);

void devm_gpio_free(struct device *dev, unsigned int gpio)
{

    WARN_ON(devres_release(dev, devm_gpio_release, devm_gpio_match,
        &gpio));
}
EXPORT_SYMBOL(devm_gpio_free);