linux/include/linux/of_gpio.h
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   1/*
   2 * OF helpers for the GPIO API
   3 *
   4 * Copyright (c) 2007-2008  MontaVista Software, Inc.
   5 *
   6 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 */
  13
  14#ifndef __LINUX_OF_GPIO_H
  15#define __LINUX_OF_GPIO_H
  16
  17#include <linux/compiler.h>
  18#include <linux/kernel.h>
  19#include <linux/errno.h>
  20#include <linux/gpio.h>
  21#include <linux/of.h>
  22
  23struct device_node;
  24
  25/*
  26 * This is Linux-specific flags. By default controllers' and Linux' mapping
  27 * match, but GPIO controllers are free to translate their own flags to
  28 * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
  29 */
  30enum of_gpio_flags {
  31        OF_GPIO_ACTIVE_LOW = 0x1,
  32};
  33
  34#ifdef CONFIG_OF_GPIO
  35
  36/*
  37 * OF GPIO chip for memory mapped banks
  38 */
  39struct of_mm_gpio_chip {
  40        struct gpio_chip gc;
  41        void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
  42        void __iomem *regs;
  43};
  44
  45static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
  46{
  47        return container_of(gc, struct of_mm_gpio_chip, gc);
  48}
  49
  50extern int of_get_named_gpio_flags(struct device_node *np,
  51                const char *list_name, int index, enum of_gpio_flags *flags);
  52
  53extern unsigned int of_gpio_named_count(struct device_node *np,
  54                                        const char* propname);
  55
  56extern int of_mm_gpiochip_add(struct device_node *np,
  57                              struct of_mm_gpio_chip *mm_gc);
  58
  59extern void of_gpiochip_add(struct gpio_chip *gc);
  60extern void of_gpiochip_remove(struct gpio_chip *gc);
  61extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  62                                const struct of_phandle_args *gpiospec,
  63                                u32 *flags);
  64
  65#else /* CONFIG_OF_GPIO */
  66
  67/* Drivers may not strictly depend on the GPIO support, so let them link. */
  68static inline int of_get_named_gpio_flags(struct device_node *np,
  69                const char *list_name, int index, enum of_gpio_flags *flags)
  70{
  71        return -ENOSYS;
  72}
  73
  74static inline unsigned int of_gpio_named_count(struct device_node *np,
  75                                        const char* propname)
  76{
  77        return 0;
  78}
  79
  80static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  81                                       const struct of_phandle_args *gpiospec,
  82                                       u32 *flags)
  83{
  84        return -ENOSYS;
  85}
  86
  87static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  88static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  89
  90#endif /* CONFIG_OF_GPIO */
  91
  92/**
  93 * of_gpio_count - Count GPIOs for a device
  94 * @np:         device node to count GPIOs for
  95 *
  96 * The function returns the count of GPIOs specified for a node.
  97 *
  98 * Note that the empty GPIO specifiers counts too. For example,
  99 *
 100 * gpios = <0
 101 *          &pio1 1 2
 102 *          0
 103 *          &pio2 3 4>;
 104 *
 105 * defines four GPIOs (so this function will return 4), two of which
 106 * are not specified.
 107 */
 108static inline unsigned int of_gpio_count(struct device_node *np)
 109{
 110        return of_gpio_named_count(np, "gpios");
 111}
 112
 113/**
 114 * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
 115 * @np:         device node to get GPIO from
 116 * @index:      index of the GPIO
 117 * @flags:      a flags pointer to fill in
 118 *
 119 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 120 * value on the error condition. If @flags is not NULL the function also fills
 121 * in flags for the GPIO.
 122 */
 123static inline int of_get_gpio_flags(struct device_node *np, int index,
 124                      enum of_gpio_flags *flags)
 125{
 126        return of_get_named_gpio_flags(np, "gpios", index, flags);
 127}
 128
 129/**
 130 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 131 * @np:         device node to get GPIO from
 132 * @propname:   Name of property containing gpio specifier(s)
 133 * @index:      index of the GPIO
 134 *
 135 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 136 * value on the error condition.
 137 */
 138static inline int of_get_named_gpio(struct device_node *np,
 139                                   const char *propname, int index)
 140{
 141        return of_get_named_gpio_flags(np, propname, index, NULL);
 142}
 143
 144/**
 145 * of_get_gpio() - Get a GPIO number to use with GPIO API
 146 * @np:         device node to get GPIO from
 147 * @index:      index of the GPIO
 148 *
 149 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 150 * value on the error condition.
 151 */
 152static inline int of_get_gpio(struct device_node *np, int index)
 153{
 154        return of_get_gpio_flags(np, index, NULL);
 155}
 156
 157#endif /* __LINUX_OF_GPIO_H */
 158
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