linux_kernel/include/linux/of_gpio.h

/*
 * OF helpers for the GPIO API
 *
 * Copyright (c) 2007-2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#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>
#include <linux/of.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,
	OF_GPIO_SINGLE_ENDED = 0x2,
	OF_GPIO_OPEN_DRAIN = 0x4,
	OF_GPIO_TRANSITORY = 0x8,
};

#ifdef CONFIG_OF_GPIO

/*
 * OF GPIO chip for memory mapped banks
 */
struct of_mm_gpio_chip {
	struct gpio_chip gc;
	void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
	void __iomem *regs;
};

static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
{
	return container_of(gc, struct of_mm_gpio_chip, gc);
}

extern int of_get_named_gpio_flags(struct device_node *np,
		const char *list_name, int index, enum of_gpio_flags *flags);

extern int of_mm_gpiochip_add_data(struct device_node *np,
				   struct of_mm_gpio_chip *mm_gc,
				   void *data);
static inline int of_mm_gpiochip_add(struct device_node *np,
				     struct of_mm_gpio_chip *mm_gc)
{
	return of_mm_gpiochip_add_data(np, mm_gc, NULL);
}
extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);

extern int of_gpio_simple_xlate(struct gpio_chip *gc,
				const struct of_phandle_args *gpiospec,
				u32 *flags);

#else /* CONFIG_OF_GPIO */

/* Drivers may not strictly depend on the GPIO support, so let them link. */
static inline int of_get_named_gpio_flags(struct device_node *np,
		const char *list_name, int index, enum of_gpio_flags *flags)
{
	if (flags)
		*flags = 0;

	return -ENOSYS;
}

static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
				       const struct of_phandle_args *gpiospec,
				       u32 *flags)
{
	return -ENOSYS;
}

#endif /* CONFIG_OF_GPIO */

/**
 * of_gpio_named_count() - Count GPIOs for a device
 * @np:		device node to count GPIOs for
 * @propname:	property name containing gpio specifier(s)
 *
 * The function returns the count of GPIOs specified for a node.
 * Note that the empty GPIO specifiers count too. Returns either
 *   Number of gpios defined in property,
 *   -EINVAL for an incorrectly formed gpios property, or
 *   -ENOENT for a missing gpios property
 *
 * Example:
 * gpios = <0
 *          &gpio1 1 2
 *          0
 *          &gpio2 3 4>;
 *
 * The above example defines four GPIOs, two of which are not specified.
 * This function will return '4'
 */
static inline int of_gpio_named_count(struct device_node *np, const char* propname)
{
	return of_count_phandle_with_args(np, propname, "#gpio-cells");
}

/**
 * of_gpio_count() - Count GPIOs for a device
 * @np:		device node to count GPIOs for
 *
 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 */
static inline int of_gpio_count(struct device_node *np)
{
	return of_gpio_named_count(np, "gpios");
}

static inline int of_get_gpio_flags(struct device_node *np, int index,
		      enum of_gpio_flags *flags)
{
	return of_get_named_gpio_flags(np, "gpios", index, flags);
}

/**
 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 * @np:		device node to get GPIO from
 * @propname:	Name of property containing gpio specifier(s)
 * @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_named_gpio(struct device_node *np,
                                   const char *propname, int index)
{
	return of_get_named_gpio_flags(np, propname, index, NULL);
}

/**
 * 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 */