Commit b908b53d authored by Anton Vorontsov's avatar Anton Vorontsov Committed by Paul Mackerras
Browse files

of/gpio: Implement of_get_gpio_flags() 



This adds a new function, of_get_gpio_flags, which is like
of_get_gpio(), but accepts a new "flags" argument.  This new function
will be used by the drivers that need to retrieve additional GPIO
information, such as active-low flag.

Also, this changes the default ("simple") .xlate routine to warn about
bogus (< 2) #gpio-cells usage: the second cell should always be present
for GPIO flags.

Signed-off-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 2fd091f3

drivers/of/gpio.c

+29 −7
Original line number Diff line number Diff line
@@ -19,14 +19,17 @@ 
#include <asm/prom.h>



/**

 * of_get_gpio - Get a GPIO number from the device tree to use with GPIO API

 * of_get_gpio_flags - Get a GPIO number and flags to use with GPIO API

 * @np:		device node to get GPIO from

 * @index:	index of the GPIO

 * @flags:	a flags pointer to fill in

 *

 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno

 * value on the error condition.

 * value on the error condition. If @flags is not NULL the function also fills

 * in flags for the GPIO.

 */

int of_get_gpio(struct device_node *np, int index)

int of_get_gpio_flags(struct device_node *np, int index,

		      enum of_gpio_flags *flags)

{

	int ret;

	struct device_node *gc;
@@ -59,7 +62,11 @@ int of_get_gpio(struct device_node *np, int index) 
		goto err1;

	}



	ret = of_gc->xlate(of_gc, np, gpio_spec);

	/* .xlate might decide to not fill in the flags, so clear it. */

	if (flags)

		*flags = 0;



	ret = of_gc->xlate(of_gc, np, gpio_spec, flags);

	if (ret < 0)

		goto err1;
@@ -70,26 +77,41 @@ err0: 
	pr_debug("%s exited with status %d\n", __func__, ret);

	return ret;

}

EXPORT_SYMBOL(of_get_gpio);

EXPORT_SYMBOL(of_get_gpio_flags);



/**

 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number

 * of_gpio_simple_xlate - translate gpio_spec to the GPIO number and flags

 * @of_gc:	pointer to the of_gpio_chip structure

 * @np:		device node of the GPIO chip

 * @gpio_spec:	gpio specifier as found in the device tree

 * @flags:	a flags pointer to fill in

 *

 * This is simple translation function, suitable for the most 1:1 mapped

 * gpio chips. This function performs only one sanity check: whether gpio

 * is less than ngpios (that is specified in the gpio_chip).

 */

int of_gpio_simple_xlate(struct of_gpio_chip *of_gc, struct device_node *np,

			 const void *gpio_spec)

			 const void *gpio_spec, enum of_gpio_flags *flags)

{

	const u32 *gpio = gpio_spec;



	/*

	 * We're discouraging gpio_cells < 2, since that way you'll have to

	 * write your own xlate function (that will have to retrive the GPIO

	 * number and the flags from a single gpio cell -- this is possible,

	 * but not recommended).

	 */

	if (of_gc->gpio_cells < 2) {

		WARN_ON(1);

		return -EINVAL;

	}



	if (*gpio > of_gc->gc.ngpio)

		return -EINVAL;



	if (flags)

		*flags = gpio[1];



	return *gpio;

}

EXPORT_SYMBOL(of_gpio_simple_xlate);

include/linux/of_gpio.h

+34 −4
Original line number Diff line number Diff line
@@ -14,9 +14,22 @@ 
#ifndef __LINUX_OF_GPIO_H

#define __LINUX_OF_GPIO_H



#include <linux/compiler.h>

#include <linux/kernel.h>

#include <linux/errno.h>

#include <linux/gpio.h>



struct device_node;



/*

 * This is Linux-specific flags. By default controllers' and Linux' mapping

 * match, but GPIO controllers are free to translate their own flags to

 * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.

 */

enum of_gpio_flags {

	OF_GPIO_ACTIVE_LOW = 0x1,

};



#ifdef CONFIG_OF_GPIO



/*
@@ -26,7 +39,7 @@ struct of_gpio_chip { 
	struct gpio_chip gc;

	int gpio_cells;

	int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,

		     const void *gpio_spec);

		     const void *gpio_spec, enum of_gpio_flags *flags);

};



static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
@@ -50,20 +63,37 @@ static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc) 
	return container_of(of_gc, struct of_mm_gpio_chip, of_gc);

}



extern int of_get_gpio(struct device_node *np, int index);

extern int of_get_gpio_flags(struct device_node *np, int index,

			     enum of_gpio_flags *flags);



extern int of_mm_gpiochip_add(struct device_node *np,

			      struct of_mm_gpio_chip *mm_gc);

extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,

				struct device_node *np,

				const void *gpio_spec);

				const void *gpio_spec,

				enum of_gpio_flags *flags);

#else



/* Drivers may not strictly depend on the GPIO support, so let them link. */

static inline int of_get_gpio(struct device_node *np, int index)

static inline int of_get_gpio_flags(struct device_node *np, int index,

				    enum of_gpio_flags *flags)

{

	return -ENOSYS;

}



#endif /* CONFIG_OF_GPIO */



/**

 * of_get_gpio - Get a GPIO number to use with GPIO API

 * @np:		device node to get GPIO from

 * @index:	index of the GPIO

 *

 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno

 * value on the error condition.

 */

static inline int of_get_gpio(struct device_node *np, int index)

{

	return of_get_gpio_flags(np, index, NULL);

}



#endif /* __LINUX_OF_GPIO_H */

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