Commit 1a0703ed authored by John Crispin's avatar John Crispin Committed by Grant Likely
Browse files

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: default avatarJohn Crispin <blogic@openwrt.org>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent e198a8de

drivers/gpio/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -2,7 +2,7 @@ 


ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG



obj-$(CONFIG_GPIOLIB)		+= gpiolib.o

obj-$(CONFIG_GPIOLIB)		+= gpiolib.o devres.o



# Device drivers. Generally keep list sorted alphabetically

obj-$(CONFIG_GPIO_GENERIC)	+= gpio-generic.o

drivers/gpio/devres.c

0 → 100644
+90 −0
Original line number Diff line number Diff line 
/*

 * 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 <blogic@openwrt.org>

 */



#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;

}



/**

 *      devm_gpio_request - request a gpio for a managed device

 *      @dev: device to request the gpio for

 *      @gpio: gpio to allocate

 *      @label: the name of the requested gpio

 *

 *      Except for the extra @dev argument, this function takes the

 *      same arguments and performs the same function as

 *      gpio_request().  GPIOs requested with this function will be

 *      automatically freed on driver detach.

 *

 *      If an GPIO allocated with this function needs to be freed

 *      separately, devm_gpio_free() must be used.

 */



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);



/**

 *      devm_gpio_free - free an interrupt

 *      @dev: device to free gpio for

 *      @gpio: gpio to free

 *

 *      Except for the extra @dev argument, this function takes the

 *      same arguments and performs the same function as gpio_free().

 *      This function instead of gpio_free() should be used to manually

 *      free GPIOs allocated with devm_gpio_request().

 */

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

{



	WARN_ON(devres_destroy(dev, devm_gpio_release, devm_gpio_match,

		&gpio));

	gpio_free(gpio);

}

EXPORT_SYMBOL(devm_gpio_free);

include/asm-generic/gpio.h

+4 −0
Original line number Diff line number Diff line
@@ -177,6 +177,10 @@ extern int gpio_request_one(unsigned gpio, unsigned long flags, const char *labe 
extern int gpio_request_array(const struct gpio *array, size_t num);

extern void gpio_free_array(const struct gpio *array, size_t num);



/* bindings for managed devices that want to request gpios */

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

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



#ifdef CONFIG_GPIO_SYSFS



/*