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 extern int of_gpio_simple_xlate(struct gpio_chip *gc, struct device_node *np,
  61                                 const void *gpio_spec, u32 *flags);
  62
  63 #else /* CONFIG_OF_GPIO */
  64
  65 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  66 static inline int of_get_named_gpio_flags(struct device_node *np,
  67                 const char *list_name, int index, enum of_gpio_flags *flags)
  68 {
  69         return -ENOSYS;
  70 }
  71
  72 static inline unsigned int of_gpio_count(struct device_node *np)
  73 {
  74         return 0;
  75 }
  76
  77 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  78                                        struct device_node *np,
  79                                        const void *gpio_spec, u32 *flags)
  80 {
  81         return -ENOSYS;
  82 }
  83
  84 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  85 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  86
  87 #endif /* CONFIG_OF_GPIO */
  88
  89 /**
  90  * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  91  * @np:         device node to get GPIO from
  92  * @index:      index of the GPIO
  93  * @flags:      a flags pointer to fill in
  94  *
  95  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  96  * value on the error condition. If @flags is not NULL the function also fills
  97  * in flags for the GPIO.
  98  */
  99 static inline int of_get_gpio_flags(struct device_node *np, int index,
 100                       enum of_gpio_flags *flags)
 101 {
 102         return of_get_named_gpio_flags(np, "gpios", index, flags);
 103 }
 104
 105 /**
 106  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 107  * @np:         device node to get GPIO from
 108  * @propname:   Name of property containing gpio specifier(s)
 109  * @index:      index of the GPIO
 110  *
 111  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 112  * value on the error condition.
 113  */
 114 static inline int of_get_named_gpio(struct device_node *np,
 115                                    const char *propname, int index)
 116 {
 117         return of_get_named_gpio_flags(np, propname, index, NULL);
 118 }
 119
 120 /**
 121  * of_get_gpio() - Get a GPIO number to use with GPIO API
 122  * @np:         device node to get GPIO from
 123  * @index:      index of the GPIO
 124  *
 125  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 126  * value on the error condition.
 127  */
 128 static inline int of_get_gpio(struct device_node *np, int index)
 129 {
 130         return of_get_gpio_flags(np, index, NULL);
 131 }
 132
 133 #endif /* __LINUX_OF_GPIO_H */