linux/drivers/gpio/devres.c
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   1/*
   2 * drivers/gpio/devres.c - managed gpio resources
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2
   6 * as published by the Free Software Foundation.
   7 *
   8 * You should have received a copy of the GNU General Public License
   9 * along with this program; if not, write to the Free Software
  10 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  11 *
  12 * This file is based on kernel/irq/devres.c
  13 *
  14 * Copyright (c) 2011 John Crispin <blogic@openwrt.org>
  15 */
  16
  17#include <linux/module.h>
  18#include <linux/gpio.h>
  19#include <linux/device.h>
  20#include <linux/gfp.h>
  21
  22static void devm_gpio_release(struct device *dev, void *res)
  23{
  24        unsigned *gpio = res;
  25
  26        gpio_free(*gpio);
  27}
  28
  29static int devm_gpio_match(struct device *dev, void *res, void *data)
  30{
  31        unsigned *this = res, *gpio = data;
  32
  33        return *this == *gpio;
  34}
  35
  36/**
  37 *      devm_gpio_request - request a gpio for a managed device
  38 *      @dev: device to request the gpio for
  39 *      @gpio: gpio to allocate
  40 *      @label: the name of the requested gpio
  41 *
  42 *      Except for the extra @dev argument, this function takes the
  43 *      same arguments and performs the same function as
  44 *      gpio_request().  GPIOs requested with this function will be
  45 *      automatically freed on driver detach.
  46 *
  47 *      If an GPIO allocated with this function needs to be freed
  48 *      separately, devm_gpio_free() must be used.
  49 */
  50
  51int devm_gpio_request(struct device *dev, unsigned gpio, const char *label)
  52{
  53        unsigned *dr;
  54        int rc;
  55
  56        dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
  57        if (!dr)
  58                return -ENOMEM;
  59
  60        rc = gpio_request(gpio, label);
  61        if (rc) {
  62                devres_free(dr);
  63                return rc;
  64        }
  65
  66        *dr = gpio;
  67        devres_add(dev, dr);
  68
  69        return 0;
  70}
  71EXPORT_SYMBOL(devm_gpio_request);
  72
  73/**
  74 *      devm_gpio_request_one - request a single GPIO with initial setup
  75 *      @dev:   device to request for
  76 *      @gpio:  the GPIO number
  77 *      @flags: GPIO configuration as specified by GPIOF_*
  78 *      @label: a literal description string of this GPIO
  79 */
  80int devm_gpio_request_one(struct device *dev, unsigned gpio,
  81                          unsigned long flags, const char *label)
  82{
  83        unsigned *dr;
  84        int rc;
  85
  86        dr = devres_alloc(devm_gpio_release, sizeof(unsigned), GFP_KERNEL);
  87        if (!dr)
  88                return -ENOMEM;
  89
  90        rc = gpio_request_one(gpio, flags, label);
  91        if (rc) {
  92                devres_free(dr);
  93                return rc;
  94        }
  95
  96        *dr = gpio;
  97        devres_add(dev, dr);
  98
  99        return 0;
 100}
 101EXPORT_SYMBOL(devm_gpio_request_one);
 102
 103/**
 104 *      devm_gpio_free - free an interrupt
 105 *      @dev: device to free gpio for
 106 *      @gpio: gpio to free
 107 *
 108 *      Except for the extra @dev argument, this function takes the
 109 *      same arguments and performs the same function as gpio_free().
 110 *      This function instead of gpio_free() should be used to manually
 111 *      free GPIOs allocated with devm_gpio_request().
 112 */
 113void devm_gpio_free(struct device *dev, unsigned int gpio)
 114{
 115
 116        WARN_ON(devres_release(dev, devm_gpio_release, devm_gpio_match,
 117                &gpio));
 118}
 119EXPORT_SYMBOL(devm_gpio_free);
 120
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