Re: [PATCH] GPIO: add bindings for managed devices

[Grant Likely <grant.likely@secretlab.ca>]

On Tue, Dec 20, 2011 at 09:40:21PM +0100, John Crispin wrote:
> 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>

Applied, thanks

g.

> ---
>  drivers/gpio/Makefile      |    2 +-
>  drivers/gpio/devres.c      |   90 ++++++++++++++++++++++++++++++++++++++++++++
>  include/asm-generic/gpio.h |    4 ++
>  3 files changed, 95 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/gpio/devres.c
> 
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index dbcb0bc..da60964 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -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
> diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
> new file mode 100644
> index 0000000..3dd2939
> --- /dev/null
> +++ b/drivers/gpio/devres.c
> @@ -0,0 +1,90 @@
> +/*
> + * 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);
> diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
> index 8c86210..8601a02 100644
> --- a/include/asm-generic/gpio.h
> +++ b/include/asm-generic/gpio.h
> @@ -175,6 +175,10 @@ 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
>  
>  /*
> -- 
> 1.7.7.1
> 
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