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
  22 struct device_node;
  23
  24 /*
  25  * This is Linux-specific flags. By default controllers' and Linux' mapping
  26  * match, but GPIO controllers are free to translate their own flags to
  27  * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
  28  */
  29 enum of_gpio_flags {
  30         OF_GPIO_ACTIVE_LOW = 0x1,
  31 };
  32
  33 #ifdef CONFIG_OF_GPIO
  34
  35 /*
  36  * OF GPIO chip for memory mapped banks
  37  */
  38 struct of_mm_gpio_chip {
  39         struct gpio_chip gc;
  40         void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
  41         void __iomem *regs;
  42 };
  43
  44 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
  45 {
  46         return container_of(gc, struct of_mm_gpio_chip, gc);
  47 }
  48
  49 extern int of_get_named_gpio_flags(struct device_node *np,
  50                 const char *list_name, int index, enum of_gpio_flags *flags);
  51
  52 extern unsigned int of_gpio_count(struct device_node *np);
  53
  54 extern int of_mm_gpiochip_add(struct device_node *np,
  55                               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 struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
  60
  61 #else /* CONFIG_OF_GPIO */
  62
  63 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  64 static inline int of_get_named_gpio_flags(struct device_node *np,
  65                 const char *list_name, int index, enum of_gpio_flags *flags)
  66 {
  67         return -ENOSYS;
  68 }
  69
  70 static inline unsigned int of_gpio_count(struct device_node *np)
  71 {
  72         return 0;
  73 }
  74
  75 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  76 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  77
  78 #endif /* CONFIG_OF_GPIO */
  79
  80 /**
  81  * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  82  * @np:         device node to get GPIO from
  83  * @index:      index of the GPIO
  84  * @flags:      a flags pointer to fill in
  85  *
  86  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  87  * value on the error condition. If @flags is not NULL the function also fills
  88  * in flags for the GPIO.
  89  */
  90 static inline int of_get_gpio_flags(struct device_node *np, int index,
  91                       enum of_gpio_flags *flags)
  92 {
  93         return of_get_named_gpio_flags(np, "gpios", index, flags);
  94 }
  95
  96 /**
  97  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
  98  * @np:         device node to get GPIO from
  99  * @propname:   Name of property containing gpio specifier(s)
 100  * @index:      index of the GPIO
 101  *
 102  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 103  * value on the error condition.
 104  */
 105 static inline int of_get_named_gpio(struct device_node *np,
 106                                    const char *propname, int index)
 107 {
 108         return of_get_named_gpio_flags(np, propname, index, NULL);
 109 }
 110
 111 /**
 112  * of_get_gpio() - Get a GPIO number to use with GPIO API
 113  * @np:         device node to get GPIO from
 114  * @index:      index of the GPIO
 115  *
 116  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 117  * value on the error condition.
 118  */
 119 static inline int of_get_gpio(struct device_node *np, int index)
 120 {
 121         return of_get_gpio_flags(np, index, NULL);
 122 }
 123
 124 #endif /* __LINUX_OF_GPIO_H */