linux/include/linux/of_gpio.h
<<
>>
Prefs
   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);
  55
  56extern void of_gpiochip_add(struct gpio_chip *gc);
  57extern void of_gpiochip_remove(struct gpio_chip *gc);
  58extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  59                                const struct of_phandle_args *gpiospec,
  60                                u32 *flags);
  61
  62#else /* CONFIG_OF_GPIO */
  63
  64/* Drivers may not strictly depend on the GPIO support, so let them link. */
  65static inline int of_get_named_gpio_flags(struct device_node *np,
  66                const char *list_name, int index, enum of_gpio_flags *flags)
  67{
  68        return -ENOSYS;
  69}
  70
  71static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  72                                       const struct of_phandle_args *gpiospec,
  73                                       u32 *flags)
  74{
  75        return -ENOSYS;
  76}
  77
  78static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  79static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  80
  81#endif /* CONFIG_OF_GPIO */
  82
  83/**
  84 * of_gpio_named_count() - Count GPIOs for a device
  85 * @np:         device node to count GPIOs for
  86 * @propname:   property name containing gpio specifier(s)
  87 *
  88 * The function returns the count of GPIOs specified for a node.
  89 * Note that the empty GPIO specifiers count too. Returns either
  90 *   Number of gpios defined in property,
  91 *   -EINVAL for an incorrectly formed gpios property, or
  92 *   -ENOENT for a missing gpios property
  93 *
  94 * Example:
  95 * gpios = <0
  96 *          &gpio1 1 2
  97 *          0
  98 *          &gpio2 3 4>;
  99 *
 100 * The above example defines four GPIOs, two of which are not specified.
 101 * This function will return '4'
 102 */
 103static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 104{
 105        return of_count_phandle_with_args(np, propname, "#gpio-cells");
 106}
 107
 108/**
 109 * of_gpio_count() - Count GPIOs for a device
 110 * @np:         device node to count GPIOs for
 111 *
 112 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 113 */
 114static inline int of_gpio_count(struct device_node *np)
 115{
 116        return of_gpio_named_count(np, "gpios");
 117}
 118
 119/**
 120 * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
 121 * @np:         device node to get GPIO from
 122 * @index:      index of the GPIO
 123 * @flags:      a flags pointer to fill in
 124 *
 125 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 126 * value on the error condition. If @flags is not NULL the function also fills
 127 * in flags for the GPIO.
 128 */
 129static inline int of_get_gpio_flags(struct device_node *np, int index,
 130                      enum of_gpio_flags *flags)
 131{
 132        return of_get_named_gpio_flags(np, "gpios", index, flags);
 133}
 134
 135/**
 136 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 137 * @np:         device node to get GPIO from
 138 * @propname:   Name of property containing gpio specifier(s)
 139 * @index:      index of the GPIO
 140 *
 141 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 142 * value on the error condition.
 143 */
 144static inline int of_get_named_gpio(struct device_node *np,
 145                                   const char *propname, int index)
 146{
 147        return of_get_named_gpio_flags(np, propname, index, NULL);
 148}
 149
 150/**
 151 * of_get_gpio() - Get a GPIO number to use with GPIO API
 152 * @np:         device node to get GPIO from
 153 * @index:      index of the GPIO
 154 *
 155 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 156 * value on the error condition.
 157 */
 158static inline int of_get_gpio(struct device_node *np, int index)
 159{
 160        return of_get_gpio_flags(np, index, NULL);
 161}
 162
 163#endif /* __LINUX_OF_GPIO_H */
 164
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.