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authorJohn Crispin <blogic@openwrt.org>2011-12-20 15:40:21 -0500
committerGrant Likely <grant.likely@secretlab.ca>2012-01-04 13:37:42 -0500
commit1a0703ede4493bd74f9c6b53f782b749e175a88e (patch)
treeee86f6148f53af7ddcc329a28f45d7679642780d /drivers
parente198a8de14d4bb122b821432fadb28eedd4b4507 (diff)
GPIO: add bindings for managed devices
This patch adds 2 functions that allow managed devices to request GPIOs. These GPIOs will then be managed by drivers/base/devres.c. Signed-off-by: John Crispin <blogic@openwrt.org> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/gpio/Makefile2
-rw-r--r--drivers/gpio/devres.c90
2 files changed, 91 insertions, 1 deletions
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 4e018d6a7639..76dbd3f55ef5 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -2,7 +2,7 @@
2 2
3ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG 3ccflags-$(CONFIG_DEBUG_GPIO) += -DDEBUG
4 4
5obj-$(CONFIG_GPIOLIB) += gpiolib.o 5obj-$(CONFIG_GPIOLIB) += gpiolib.o devres.o
6 6
7# Device drivers. Generally keep list sorted alphabetically 7# Device drivers. Generally keep list sorted alphabetically
8obj-$(CONFIG_GPIO_GENERIC) += gpio-generic.o 8obj-$(CONFIG_GPIO_GENERIC) += gpio-generic.o
diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
new file mode 100644
index 000000000000..3dd29399cef5
--- /dev/null
+++ b/drivers/gpio/devres.c
@@ -0,0 +1,90 @@
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_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 */
83void 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}
90EXPORT_SYMBOL(devm_gpio_free);