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
devm_gpio_release(struct device * dev,void * res)22 static void devm_gpio_release(struct device *dev, void *res)
23 {
24 unsigned *gpio = res;
25
26 gpio_free(*gpio);
27 }
28
devm_gpio_match(struct device * dev,void * res,void * data)29 static 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
devm_gpio_request(struct device * dev,unsigned gpio,const char * label)51 int 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 }
71 EXPORT_SYMBOL(devm_gpio_request);
72
73 /**
74 * devm_gpio_free - free an interrupt
75 * @dev: device to free gpio for
76 * @gpio: gpio to free
77 *
78 * Except for the extra @dev argument, this function takes the
79 * same arguments and performs the same function as gpio_free().
80 * This function instead of gpio_free() should be used to manually
81 * free GPIOs allocated with devm_gpio_request().
82 */
devm_gpio_free(struct device * dev,unsigned int gpio)83 void devm_gpio_free(struct device *dev, unsigned int gpio)
84 {
85
86 WARN_ON(devres_destroy(dev, devm_gpio_release, devm_gpio_match,
87 &gpio));
88 gpio_free(gpio);
89 }
90 EXPORT_SYMBOL(devm_gpio_free);
91