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_gpio_flags(struct device_node *np, int index,
  50                              enum of_gpio_flags *flags);
  51 extern unsigned int of_gpio_count(struct device_node *np);
  52
  53 extern int of_mm_gpiochip_add(struct device_node *np,
  54                               struct of_mm_gpio_chip *mm_gc);
  55
  56 extern void of_gpiochip_add(struct gpio_chip *gc);
  57 extern void of_gpiochip_remove(struct gpio_chip *gc);
  58 extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
  59
  60 #else /* CONFIG_OF_GPIO */
  61
  62 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  63 static inline int of_get_gpio_flags(struct device_node *np, int index,
  64                                     enum of_gpio_flags *flags)
  65 {
  66         return -ENOSYS;
  67 }
  68
  69 static inline unsigned int of_gpio_count(struct device_node *np)
  70 {
  71         return 0;
  72 }
  73
  74 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  75 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  76
  77 #endif /* CONFIG_OF_GPIO */
  78
  79 /**
  80  * of_get_gpio - Get a GPIO number to use with GPIO API
  81  * @np:         device node to get GPIO from
  82  * @index:      index of the GPIO
  83  *
  84  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  85  * value on the error condition.
  86  */
  87 static inline int of_get_gpio(struct device_node *np, int index)
  88 {
  89         return of_get_gpio_flags(np, index, NULL);
  90 }
  91
  92 #endif /* __LINUX_OF_GPIO_H */