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 unsigned int of_gpio_named_count(struct device_node *np,
  54                                         const char* propname);
  55
  56 extern int of_mm_gpiochip_add(struct device_node *np,
  57                               struct of_mm_gpio_chip *mm_gc);
  58
  59 extern void of_gpiochip_add(struct gpio_chip *gc);
  60 extern void of_gpiochip_remove(struct gpio_chip *gc);
  61 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  62                                 const struct of_phandle_args *gpiospec,
  63                                 u32 *flags);
  64
  65 #else /* CONFIG_OF_GPIO */
  66
  67 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  68 static inline int of_get_named_gpio_flags(struct device_node *np,
  69                 const char *list_name, int index, enum of_gpio_flags *flags)
  70 {
  71         return -ENOSYS;
  72 }
  73
  74 static inline unsigned int of_gpio_named_count(struct device_node *np,
  75                                         const char* propname)
  76 {
  77         return 0;
  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 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  88 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  89
  90 #endif /* CONFIG_OF_GPIO */
  91
  92 /**
  93  * of_gpio_count - Count GPIOs for a device
  94  * @np:         device node to count GPIOs for
  95  *
  96  * The function returns the count of GPIOs specified for a node.
  97  *
  98  * Note that the empty GPIO specifiers counts too. For example,
  99  *
 100  * gpios = <0
 101  *          &pio1 1 2
 102  *          0
 103  *          &pio2 3 4>;
 104  *
 105  * defines four GPIOs (so this function will return 4), two of which
 106  * are not specified.
 107  */
 108 static inline unsigned int of_gpio_count(struct device_node *np)
 109 {
 110         return of_gpio_named_count(np, "gpios");
 111 }
 112
 113 /**
 114  * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
 115  * @np:         device node to get GPIO from
 116  * @index:      index of the GPIO
 117  * @flags:      a flags pointer to fill in
 118  *
 119  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 120  * value on the error condition. If @flags is not NULL the function also fills
 121  * in flags for the GPIO.
 122  */
 123 static inline int of_get_gpio_flags(struct device_node *np, int index,
 124                       enum of_gpio_flags *flags)
 125 {
 126         return of_get_named_gpio_flags(np, "gpios", index, flags);
 127 }
 128
 129 /**
 130  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 131  * @np:         device node to get GPIO from
 132  * @propname:   Name of property containing gpio specifier(s)
 133  * @index:      index of the GPIO
 134  *
 135  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 136  * value on the error condition.
 137  */
 138 static inline int of_get_named_gpio(struct device_node *np,
 139                                    const char *propname, int index)
 140 {
 141         return of_get_named_gpio_flags(np, propname, index, NULL);
 142 }
 143
 144 /**
 145  * of_get_gpio() - Get a GPIO number to use with GPIO API
 146  * @np:         device node to get GPIO from
 147  * @index:      index of the GPIO
 148  *
 149  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 150  * value on the error condition.
 151  */
 152 static inline int of_get_gpio(struct device_node *np, int index)
 153 {
 154         return of_get_gpio_flags(np, index, NULL);
 155 }
 156
 157 #endif /* __LINUX_OF_GPIO_H */