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         OF_GPIO_SINGLE_ENDED = 0x2,
  33         OF_GPIO_OPEN_DRAIN = 0x4,
  34         OF_GPIO_SLEEP_MAY_LOSE_VALUE = 0x8,
  35 };
  36
  37 #ifdef CONFIG_OF_GPIO
  38
  39 /*
  40  * OF GPIO chip for memory mapped banks
  41  */
  42 struct of_mm_gpio_chip {
  43         struct gpio_chip gc;
  44         void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
  45         void __iomem *regs;
  46 };
  47
  48 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
  49 {
  50         return container_of(gc, struct of_mm_gpio_chip, gc);
  51 }
  52
  53 extern int of_get_named_gpio_flags(struct device_node *np,
  54                 const char *list_name, int index, enum of_gpio_flags *flags);
  55
  56 extern int of_mm_gpiochip_add_data(struct device_node *np,
  57                                    struct of_mm_gpio_chip *mm_gc,
  58                                    void *data);
  59 static inline int of_mm_gpiochip_add(struct device_node *np,
  60                                      struct of_mm_gpio_chip *mm_gc)
  61 {
  62         return of_mm_gpiochip_add_data(np, mm_gc, NULL);
  63 }
  64 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
  65
  66 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  67                                 const struct of_phandle_args *gpiospec,
  68                                 u32 *flags);
  69
  70 #else /* CONFIG_OF_GPIO */
  71
  72 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  73 static inline int of_get_named_gpio_flags(struct device_node *np,
  74                 const char *list_name, int index, enum of_gpio_flags *flags)
  75 {
  76         if (flags)
  77                 *flags = 0;
  78
  79         return -ENOSYS;
  80 }
  81
  82 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  83                                        const struct of_phandle_args *gpiospec,
  84                                        u32 *flags)
  85 {
  86         return -ENOSYS;
  87 }
  88
  89 #endif /* CONFIG_OF_GPIO */
  90
  91 /**
  92  * of_gpio_named_count() - Count GPIOs for a device
  93  * @np:         device node to count GPIOs for
  94  * @propname:   property name containing gpio specifier(s)
  95  *
  96  * The function returns the count of GPIOs specified for a node.
  97  * Note that the empty GPIO specifiers count too. Returns either
  98  *   Number of gpios defined in property,
  99  *   -EINVAL for an incorrectly formed gpios property, or
 100  *   -ENOENT for a missing gpios property
 101  *
 102  * Example:
 103  * gpios = <0
 104  *          &gpio1 1 2
 105  *          0
 106  *          &gpio2 3 4>;
 107  *
 108  * The above example defines four GPIOs, two of which are not specified.
 109  * This function will return '4'
 110  */
 111 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 112 {
 113         return of_count_phandle_with_args(np, propname, "#gpio-cells");
 114 }
 115
 116 /**
 117  * of_gpio_count() - Count GPIOs for a device
 118  * @np:         device node to count GPIOs for
 119  *
 120  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 121  */
 122 static inline int of_gpio_count(struct device_node *np)
 123 {
 124         return of_gpio_named_count(np, "gpios");
 125 }
 126
 127 static inline int of_get_gpio_flags(struct device_node *np, int index,
 128                       enum of_gpio_flags *flags)
 129 {
 130         return of_get_named_gpio_flags(np, "gpios", index, flags);
 131 }
 132
 133 /**
 134  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 135  * @np:         device node to get GPIO from
 136  * @propname:   Name of property containing gpio specifier(s)
 137  * @index:      index of the GPIO
 138  *
 139  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 140  * value on the error condition.
 141  */
 142 static inline int of_get_named_gpio(struct device_node *np,
 143                                    const char *propname, int index)
 144 {
 145         return of_get_named_gpio_flags(np, propname, index, NULL);
 146 }
 147
 148 /**
 149  * of_get_gpio() - Get a GPIO number to use with GPIO API
 150  * @np:         device node to get GPIO from
 151  * @index:      index of the GPIO
 152  *
 153  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 154  * value on the error condition.
 155  */
 156 static inline int of_get_gpio(struct device_node *np, int index)
 157 {
 158         return of_get_gpio_flags(np, index, NULL);
 159 }
 160
 161 #endif /* __LINUX_OF_GPIO_H */