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 #include <linux/gpio/consumer.h>
  23
  24 struct device_node;
  25
  26 /*
  27  * This is Linux-specific flags. By default controllers' and Linux' mapping
  28  * match, but GPIO controllers are free to translate their own flags to
  29  * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
  30  */
  31 enum of_gpio_flags {
  32         OF_GPIO_ACTIVE_LOW = 0x1,
  33 };
  34
  35 #ifdef CONFIG_OF_GPIO
  36
  37 /*
  38  * OF GPIO chip for memory mapped banks
  39  */
  40 struct of_mm_gpio_chip {
  41         struct gpio_chip gc;
  42         void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
  43         void __iomem *regs;
  44 };
  45
  46 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
  47 {
  48         return container_of(gc, struct of_mm_gpio_chip, gc);
  49 }
  50
  51 extern struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  52                 const char *list_name, int index, enum of_gpio_flags *flags);
  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 int of_gpio_simple_xlate(struct gpio_chip *gc,
  60                                 const struct of_phandle_args *gpiospec,
  61                                 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 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
  67                 const char *list_name, int index, enum of_gpio_flags *flags)
  68 {
  69         return ERR_PTR(-ENOSYS);
  70 }
  71
  72 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  73                                        const struct of_phandle_args *gpiospec,
  74                                        u32 *flags)
  75 {
  76         return -ENOSYS;
  77 }
  78
  79 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
  80 static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
  81
  82 #endif /* CONFIG_OF_GPIO */
  83
  84 static inline int of_get_named_gpio_flags(struct device_node *np,
  85                 const char *list_name, int index, enum of_gpio_flags *flags)
  86 {
  87         struct gpio_desc *desc;
  88         desc = of_get_named_gpiod_flags(np, list_name, index, flags);
  89
  90         if (IS_ERR(desc))
  91                 return PTR_ERR(desc);
  92         else
  93                 return desc_to_gpio(desc);
  94 }
  95
  96 /**
  97  * of_gpio_named_count() - Count GPIOs for a device
  98  * @np:         device node to count GPIOs for
  99  * @propname:   property name containing gpio specifier(s)
 100  *
 101  * The function returns the count of GPIOs specified for a node.
 102  * Note that the empty GPIO specifiers count too. Returns either
 103  *   Number of gpios defined in property,
 104  *   -EINVAL for an incorrectly formed gpios property, or
 105  *   -ENOENT for a missing gpios property
 106  *
 107  * Example:
 108  * gpios = <0
 109  *          &gpio1 1 2
 110  *          0
 111  *          &gpio2 3 4>;
 112  *
 113  * The above example defines four GPIOs, two of which are not specified.
 114  * This function will return '4'
 115  */
 116 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 117 {
 118         return of_count_phandle_with_args(np, propname, "#gpio-cells");
 119 }
 120
 121 /**
 122  * of_gpio_count() - Count GPIOs for a device
 123  * @np:         device node to count GPIOs for
 124  *
 125  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 126  */
 127 static inline int of_gpio_count(struct device_node *np)
 128 {
 129         return of_gpio_named_count(np, "gpios");
 130 }
 131
 132 /**
 133  * of_get_gpiod_flags() - Get a GPIO descriptor and flags to use with GPIO API
 134  * @np:         device node to get GPIO from
 135  * @index:      index of the GPIO
 136  * @flags:      a flags pointer to fill in
 137  *
 138  * Returns GPIO descriptor to use with Linux generic GPIO API, or a errno
 139  * value on the error condition. If @flags is not NULL the function also fills
 140  * in flags for the GPIO.
 141  */
 142 static inline struct gpio_desc *of_get_gpiod_flags(struct device_node *np,
 143                                         int index, enum of_gpio_flags *flags)
 144 {
 145         return of_get_named_gpiod_flags(np, "gpios", index, flags);
 146 }
 147
 148 static inline int of_get_gpio_flags(struct device_node *np, int index,
 149                       enum of_gpio_flags *flags)
 150 {
 151         return of_get_named_gpio_flags(np, "gpios", index, flags);
 152 }
 153
 154 /**
 155  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 156  * @np:         device node to get GPIO from
 157  * @propname:   Name of property containing gpio specifier(s)
 158  * @index:      index of the GPIO
 159  *
 160  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 161  * value on the error condition.
 162  */
 163 static inline int of_get_named_gpio(struct device_node *np,
 164                                    const char *propname, int index)
 165 {
 166         return of_get_named_gpio_flags(np, propname, index, NULL);
 167 }
 168
 169 /**
 170  * of_get_gpio() - Get a GPIO number to use with GPIO API
 171  * @np:         device node to get GPIO from
 172  * @index:      index of the GPIO
 173  *
 174  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 175  * value on the error condition.
 176  */
 177 static inline int of_get_gpio(struct device_node *np, int index)
 178 {
 179         return of_get_gpio_flags(np, index, NULL);
 180 }
 181
 182 #endif /* __LINUX_OF_GPIO_H */