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_data(struct device_node *np,
  55                                    struct of_mm_gpio_chip *mm_gc,
  56                                    void *data);
  57 static inline int of_mm_gpiochip_add(struct device_node *np,
  58                                      struct of_mm_gpio_chip *mm_gc)
  59 {
  60         return of_mm_gpiochip_add_data(np, mm_gc, NULL);
  61 }
  62 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
  63
  64 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  65                                 const struct of_phandle_args *gpiospec,
  66                                 u32 *flags);
  67
  68 #else /* CONFIG_OF_GPIO */
  69
  70 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  71 static inline int of_get_named_gpio_flags(struct device_node *np,
  72                 const char *list_name, int index, enum of_gpio_flags *flags)
  73 {
  74         if (flags)
  75                 *flags = 0;
  76
  77         return -ENOSYS;
  78 }
  79
  80 static 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
  87 #endif /* CONFIG_OF_GPIO */
  88
  89 /**
  90  * of_gpio_named_count() - Count GPIOs for a device
  91  * @np:         device node to count GPIOs for
  92  * @propname:   property name containing gpio specifier(s)
  93  *
  94  * The function returns the count of GPIOs specified for a node.
  95  * Note that the empty GPIO specifiers count too. Returns either
  96  *   Number of gpios defined in property,
  97  *   -EINVAL for an incorrectly formed gpios property, or
  98  *   -ENOENT for a missing gpios property
  99  *
 100  * Example:
 101  * gpios = <0
 102  *          &gpio1 1 2
 103  *          0
 104  *          &gpio2 3 4>;
 105  *
 106  * The above example defines four GPIOs, two of which are not specified.
 107  * This function will return '4'
 108  */
 109 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 110 {
 111         return of_count_phandle_with_args(np, propname, "#gpio-cells");
 112 }
 113
 114 /**
 115  * of_gpio_count() - Count GPIOs for a device
 116  * @np:         device node to count GPIOs for
 117  *
 118  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 119  */
 120 static inline int of_gpio_count(struct device_node *np)
 121 {
 122         return of_gpio_named_count(np, "gpios");
 123 }
 124
 125 static inline int of_get_gpio_flags(struct device_node *np, int index,
 126                       enum of_gpio_flags *flags)
 127 {
 128         return of_get_named_gpio_flags(np, "gpios", index, flags);
 129 }
 130
 131 /**
 132  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 133  * @np:         device node to get GPIO from
 134  * @propname:   Name of property containing gpio specifier(s)
 135  * @index:      index of the GPIO
 136  *
 137  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 138  * value on the error condition.
 139  */
 140 static inline int of_get_named_gpio(struct device_node *np,
 141                                    const char *propname, int index)
 142 {
 143         return of_get_named_gpio_flags(np, propname, index, NULL);
 144 }
 145
 146 /**
 147  * of_get_gpio() - Get a GPIO number to use with GPIO API
 148  * @np:         device node to get GPIO from
 149  * @index:      index of the GPIO
 150  *
 151  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 152  * value on the error condition.
 153  */
 154 static inline int of_get_gpio(struct device_node *np, int index)
 155 {
 156         return of_get_gpio_flags(np, index, NULL);
 157 }
 158
 159 #endif /* __LINUX_OF_GPIO_H */