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_gpiochip_add(struct gpio_chip *gc);
  65 extern void of_gpiochip_remove(struct gpio_chip *gc);
  66 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  67                                 const struct of_phandle_args *gpiospec,
  68                                 u32 *flags);
  69
  70 #else /* CONFIG_OF_GPIO */
  71
  72 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  73 static inline int of_get_named_gpio_flags(struct device_node *np,
  74                 const char *list_name, int index, enum of_gpio_flags *flags)
  75 {
  76         if (flags)
  77                 *flags = 0;
  78
  79         return -ENOSYS;
  80 }
  81
  82 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  83                                        const struct of_phandle_args *gpiospec,
  84                                        u32 *flags)
  85 {
  86         return -ENOSYS;
  87 }
  88
  89 static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; }
  90 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  91
  92 #endif /* CONFIG_OF_GPIO */
  93
  94 /**
  95  * of_gpio_named_count() - Count GPIOs for a device
  96  * @np:         device node to count GPIOs for
  97  * @propname:   property name containing gpio specifier(s)
  98  *
  99  * The function returns the count of GPIOs specified for a node.
 100  * Note that the empty GPIO specifiers count too. Returns either
 101  *   Number of gpios defined in property,
 102  *   -EINVAL for an incorrectly formed gpios property, or
 103  *   -ENOENT for a missing gpios property
 104  *
 105  * Example:
 106  * gpios = <0
 107  *          &gpio1 1 2
 108  *          0
 109  *          &gpio2 3 4>;
 110  *
 111  * The above example defines four GPIOs, two of which are not specified.
 112  * This function will return '4'
 113  */
 114 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 115 {
 116         return of_count_phandle_with_args(np, propname, "#gpio-cells");
 117 }
 118
 119 /**
 120  * of_gpio_count() - Count GPIOs for a device
 121  * @np:         device node to count GPIOs for
 122  *
 123  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 124  */
 125 static inline int of_gpio_count(struct device_node *np)
 126 {
 127         return of_gpio_named_count(np, "gpios");
 128 }
 129
 130 static inline int of_get_gpio_flags(struct device_node *np, int index,
 131                       enum of_gpio_flags *flags)
 132 {
 133         return of_get_named_gpio_flags(np, "gpios", index, flags);
 134 }
 135
 136 /**
 137  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 138  * @np:         device node to get GPIO from
 139  * @propname:   Name of property containing gpio specifier(s)
 140  * @index:      index of the GPIO
 141  *
 142  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 143  * value on the error condition.
 144  */
 145 static inline int of_get_named_gpio(struct device_node *np,
 146                                    const char *propname, int index)
 147 {
 148         return of_get_named_gpio_flags(np, propname, index, NULL);
 149 }
 150
 151 /**
 152  * of_get_gpio() - Get a GPIO number to use with GPIO API
 153  * @np:         device node to get GPIO from
 154  * @index:      index of the GPIO
 155  *
 156  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 157  * value on the error condition.
 158  */
 159 static inline int of_get_gpio(struct device_node *np, int index)
 160 {
 161         return of_get_gpio_flags(np, index, NULL);
 162 }
 163
 164 #endif /* __LINUX_OF_GPIO_H */