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_count(struct device_node *np);
  54
  55 extern int of_mm_gpiochip_add(struct device_node *np,
  56                               struct of_mm_gpio_chip *mm_gc);
  57
  58 extern void of_gpiochip_add(struct gpio_chip *gc);
  59 extern void of_gpiochip_remove(struct gpio_chip *gc);
  60 extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
  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_count(struct device_node *np)
  75 {
  76         return 0;
  77 }
  78
  79 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  80                                        const struct of_phandle_args *gpiospec,
  81                                        u32 *flags)
  82 {
  83         return -ENOSYS;
  84 }
  85
  86 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  87 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  88
  89 #endif /* CONFIG_OF_GPIO */
  90
  91 /**
  92  * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  93  * @np:         device node to get GPIO from
  94  * @index:      index of the GPIO
  95  * @flags:      a flags pointer to fill in
  96  *
  97  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
  98  * value on the error condition. If @flags is not NULL the function also fills
  99  * in flags for the GPIO.
 100  */
 101 static inline int of_get_gpio_flags(struct device_node *np, int index,
 102                       enum of_gpio_flags *flags)
 103 {
 104         return of_get_named_gpio_flags(np, "gpios", index, flags);
 105 }
 106
 107 /**
 108  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 109  * @np:         device node to get GPIO from
 110  * @propname:   Name of property containing gpio specifier(s)
 111  * @index:      index of the GPIO
 112  *
 113  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 114  * value on the error condition.
 115  */
 116 static inline int of_get_named_gpio(struct device_node *np,
 117                                    const char *propname, int index)
 118 {
 119         return of_get_named_gpio_flags(np, propname, index, NULL);
 120 }
 121
 122 /**
 123  * of_get_gpio() - Get a GPIO number to use with GPIO API
 124  * @np:         device node to get GPIO from
 125  * @index:      index of the GPIO
 126  *
 127  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 128  * value on the error condition.
 129  */
 130 static inline int of_get_gpio(struct device_node *np, int index)
 131 {
 132         return of_get_gpio_flags(np, index, NULL);
 133 }
 134
 135 #endif /* __LINUX_OF_GPIO_H */