include/linux/of_gpio.h

   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
  23 struct 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  */
  30 enum of_gpio_flags {
  31         OF_GPIO_ACTIVE_LOW = 0x1,
  32         OF_GPIO_SINGLE_ENDED = 0x2,
  33 };
  34
  35 #ifdef CONFIG_OF_GPIO
  36
  37 /*
  38  * OF GPIO chip for memory mapped banks
  39  */
  40 struct of_mm_gpio_chip {
  41         struct gpio_chip gc;
  42         void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
  43         void __iomem *regs;
  44 };
  45
  46 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
  47 {
  48         return container_of(gc, struct of_mm_gpio_chip, gc);
  49 }
  50
  51 extern int of_get_named_gpio_flags(struct device_node *np,
  52                 const char *list_name, int index, enum of_gpio_flags *flags);
  53
  54 extern int of_mm_gpiochip_add(struct device_node *np,
  55                               struct of_mm_gpio_chip *mm_gc);
  56 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
  57
  58 extern int of_gpiochip_add(struct gpio_chip *gc);
  59 extern void of_gpiochip_remove(struct gpio_chip *gc);
  60 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  61                                 const struct of_phandle_args *gpiospec,
  62                                 u32 *flags);
  63
  64 #else /* CONFIG_OF_GPIO */
  65
  66 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  67 static inline int of_get_named_gpio_flags(struct device_node *np,
  68                 const char *list_name, int index, enum of_gpio_flags *flags)
  69 {
  70         return -ENOSYS;
  71 }
  72
  73 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  74                                        const struct of_phandle_args *gpiospec,
  75                                        u32 *flags)
  76 {
  77         return -ENOSYS;
  78 }
  79
  80 static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; }
  81 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  82
  83 #endif /* CONFIG_OF_GPIO */
  84
  85 /**
  86  * of_gpio_named_count() - Count GPIOs for a device
  87  * @np:         device node to count GPIOs for
  88  * @propname:   property name containing gpio specifier(s)
  89  *
  90  * The function returns the count of GPIOs specified for a node.
  91  * Note that the empty GPIO specifiers count too. Returns either
  92  *   Number of gpios defined in property,
  93  *   -EINVAL for an incorrectly formed gpios property, or
  94  *   -ENOENT for a missing gpios property
  95  *
  96  * Example:
  97  * gpios = <0
  98  *          &gpio1 1 2
  99  *          0
 100  *          &gpio2 3 4>;
 101  *
 102  * The above example defines four GPIOs, two of which are not specified.
 103  * This function will return '4'
 104  */
 105 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 106 {
 107         return of_count_phandle_with_args(np, propname, "#gpio-cells");
 108 }
 109
 110 /**
 111  * of_gpio_count() - Count GPIOs for a device
 112  * @np:         device node to count GPIOs for
 113  *
 114  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 115  */
 116 static inline int of_gpio_count(struct device_node *np)
 117 {
 118         return of_gpio_named_count(np, "gpios");
 119 }
 120
 121 static inline int of_get_gpio_flags(struct device_node *np, int index,
 122                       enum of_gpio_flags *flags)
 123 {
 124         return of_get_named_gpio_flags(np, "gpios", index, flags);
 125 }
 126
 127 /**
 128  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 129  * @np:         device node to get GPIO from
 130  * @propname:   Name of property containing gpio specifier(s)
 131  * @index:      index of the GPIO
 132  *
 133  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 134  * value on the error condition.
 135  */
 136 static inline int of_get_named_gpio(struct device_node *np,
 137                                    const char *propname, int index)
 138 {
 139         return of_get_named_gpio_flags(np, propname, index, NULL);
 140 }
 141
 142 /**
 143  * of_get_gpio() - Get a GPIO number to use with GPIO API
 144  * @np:         device node to get GPIO from
 145  * @index:      index of the GPIO
 146  *
 147  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 148  * value on the error condition.
 149  */
 150 static inline int of_get_gpio(struct device_node *np, int index)
 151 {
 152         return of_get_gpio_flags(np, index, NULL);
 153 }
 154
 155 #endif /* __LINUX_OF_GPIO_H */