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 };
  33
  34 #ifdef CONFIG_OF_GPIO
  35
  36 /*
  37  * OF GPIO chip for memory mapped banks
  38  */
  39 struct 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
  45 static 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
  50 extern int of_get_named_gpio_flags(struct device_node *np,
  51                 const char *list_name, int index, enum of_gpio_flags *flags);
  52
  53 extern int of_mm_gpiochip_add(struct device_node *np,
  54                               struct of_mm_gpio_chip *mm_gc);
  55 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
  56
  57 extern void of_gpiochip_add(struct gpio_chip *gc);
  58 extern void of_gpiochip_remove(struct gpio_chip *gc);
  59 extern 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. */
  66 static 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
  72 static 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
  79 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  80 static 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  */
 104 static 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  */
 115 static inline int of_gpio_count(struct device_node *np)
 116 {
 117         return of_gpio_named_count(np, "gpios");
 118 }
 119
 120 static 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  */
 135 static 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  */
 149 static 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 */