LXR linux/include/linux/of

   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 int of_mm_gpiochip_add(struct device_node *np,
  54                              struct of_mm_gpio_chip *mm_gc);
  55extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
  56
  57extern void of_gpiochip_add(struct gpio_chip *gc);
  58extern void of_gpiochip_remove(struct gpio_chip *gc);
  59extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  60                                const struct of_phandle_args *gpiospec,
  61                                u32 *flags);
  62
  63#else /* CONFIG_OF_GPIO */
  64
  65/* Drivers may not strictly depend on the GPIO support, so let them link. */
  66static inline int of_get_named_gpio_flags(struct device_node *np,
  67                const char *list_name, int index, enum of_gpio_flags *flags)
  68{
  69        return -ENOSYS;
  70}
  71
  72static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  73                                       const struct of_phandle_args *gpiospec,
  74                                       u32 *flags)
  75{
  76        return -ENOSYS;
  77}
  78
  79static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  80static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  81
  82#endif /* CONFIG_OF_GPIO */
  83
  84/**
  85 * of_gpio_named_count() - Count GPIOs for a device
  86 * @np:         device node to count GPIOs for
  87 * @propname:   property name containing gpio specifier(s)
  88 *
  89 * The function returns the count of GPIOs specified for a node.
  90 * Note that the empty GPIO specifiers count too. Returns either
  91 *   Number of gpios defined in property,
  92 *   -EINVAL for an incorrectly formed gpios property, or
  93 *   -ENOENT for a missing gpios property
  94 *
  95 * Example:
  96 * gpios = <0
  97 *          &gpio1 1 2
  98 *          0
  99 *          &gpio2 3 4>;
 100 *
 101 * The above example defines four GPIOs, two of which are not specified.
 102 * This function will return '4'
 103 */
 104static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 105{
 106        return of_count_phandle_with_args(np, propname, "#gpio-cells");
 107}
 108
 109/**
 110 * of_gpio_count() - Count GPIOs for a device
 111 * @np:         device node to count GPIOs for
 112 *
 113 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 114 */
 115static inline int of_gpio_count(struct device_node *np)
 116{
 117        return of_gpio_named_count(np, "gpios");
 118}
 119
 120static inline int of_get_gpio_flags(struct device_node *np, int index,
 121                      enum of_gpio_flags *flags)
 122{
 123        return of_get_named_gpio_flags(np, "gpios", index, flags);
 124}
 125
 126/**
 127 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 128 * @np:         device node to get GPIO from
 129 * @propname:   Name of property containing gpio specifier(s)
 130 * @index:      index of the GPIO
 131 *
 132 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 133 * value on the error condition.
 134 */
 135static inline int of_get_named_gpio(struct device_node *np,
 136                                   const char *propname, int index)
 137{
 138        return of_get_named_gpio_flags(np, propname, index, NULL);
 139}
 140
 141/**
 142 * of_get_gpio() - Get a GPIO number to use with GPIO API
 143 * @np:         device node to get GPIO from
 144 * @index:      index of the GPIO
 145 *
 146 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 147 * value on the error condition.
 148 */
 149static inline int of_get_gpio(struct device_node *np, int index)
 150{
 151        return of_get_gpio_flags(np, index, NULL);
 152}
 153
 154#endif /* __LINUX_OF_GPIO_H */
 155