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  * Generic OF GPIO chip
  37  */
  38 struct of_gpio_chip {
  39         struct gpio_chip gc;
  40         int gpio_cells;
  41         int (*xlate)(struct of_gpio_chip *of_gc, struct device_node *np,
  42                      const void *gpio_spec, enum of_gpio_flags *flags);
  43 };
  44
  45 static inline struct of_gpio_chip *to_of_gpio_chip(struct gpio_chip *gc)
  46 {
  47         return container_of(gc, struct of_gpio_chip, gc);
  48 }
  49
  50 /*
  51  * OF GPIO chip for memory mapped banks
  52  */
  53 struct of_mm_gpio_chip {
  54         struct of_gpio_chip of_gc;
  55         void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
  56         void __iomem *regs;
  57 };
  58
  59 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
  60 {
  61         struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
  62
  63         return container_of(of_gc, struct of_mm_gpio_chip, of_gc);
  64 }
  65
  66 extern int of_get_gpio_flags(struct device_node *np, int index,
  67                              enum of_gpio_flags *flags);
  68 extern unsigned int of_gpio_count(struct device_node *np);
  69
  70 extern int of_mm_gpiochip_add(struct device_node *np,
  71                               struct of_mm_gpio_chip *mm_gc);
  72 extern int of_gpio_simple_xlate(struct of_gpio_chip *of_gc,
  73                                 struct device_node *np,
  74                                 const void *gpio_spec,
  75                                 enum of_gpio_flags *flags);
  76 #else
  77
  78 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  79 static inline int of_get_gpio_flags(struct device_node *np, int index,
  80                                     enum of_gpio_flags *flags)
  81 {
  82         return -ENOSYS;
  83 }
  84
  85 static inline unsigned int of_gpio_count(struct device_node *np)
  86 {
  87         return 0;
  88 }
  89
  90 #endif /* CONFIG_OF_GPIO */
  91
  92 /**
  93  * of_get_gpio - Get a GPIO number to use with GPIO API
  94  * @np:         device node to get GPIO from
  95  * @index:      index of the GPIO
  96  *
  97  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  98  * value on the error condition.
  99  */
 100 static inline int of_get_gpio(struct device_node *np, int index)
 101 {
 102         return of_get_gpio_flags(np, index, NULL);
 103 }
 104
 105 #endif /* __LINUX_OF_GPIO_H */