include/linux/of_gpio.h

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * OF helpers for the GPIO API
   4  *
   5  * Copyright (c) 2007-2008  MontaVista Software, Inc.
   6  *
   7  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
   8  */
   9
  10 #ifndef __LINUX_OF_GPIO_H
  11 #define __LINUX_OF_GPIO_H
  12
  13 #include <linux/compiler.h>
  14 #include <linux/kernel.h>
  15 #include <linux/errno.h>
  16 #include <linux/gpio.h>
  17 #include <linux/of.h>
  18
  19 struct device_node;
  20
  21 /*
  22  * This is Linux-specific flags. By default controllers' and Linux' mapping
  23  * match, but GPIO controllers are free to translate their own flags to
  24  * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
  25  */
  26 enum of_gpio_flags {
  27         OF_GPIO_ACTIVE_LOW = 0x1,
  28         OF_GPIO_SINGLE_ENDED = 0x2,
  29         OF_GPIO_OPEN_DRAIN = 0x4,
  30         OF_GPIO_TRANSITORY = 0x8,
  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 int of_mm_gpiochip_add_data(struct device_node *np,
  53                                    struct of_mm_gpio_chip *mm_gc,
  54                                    void *data);
  55 static inline int of_mm_gpiochip_add(struct device_node *np,
  56                                      struct of_mm_gpio_chip *mm_gc)
  57 {
  58         return of_mm_gpiochip_add_data(np, mm_gc, NULL);
  59 }
  60 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
  61
  62 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
  63                                 const struct of_phandle_args *gpiospec,
  64                                 u32 *flags);
  65
  66 #else /* CONFIG_OF_GPIO */
  67
  68 /* Drivers may not strictly depend on the GPIO support, so let them link. */
  69 static inline int of_get_named_gpio_flags(struct device_node *np,
  70                 const char *list_name, int index, enum of_gpio_flags *flags)
  71 {
  72         if (flags)
  73                 *flags = 0;
  74
  75         return -ENOSYS;
  76 }
  77
  78 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
  79                                        const struct of_phandle_args *gpiospec,
  80                                        u32 *flags)
  81 {
  82         return -ENOSYS;
  83 }
  84
  85 #endif /* CONFIG_OF_GPIO */
  86
  87 /**
  88  * of_gpio_named_count() - Count GPIOs for a device
  89  * @np:         device node to count GPIOs for
  90  * @propname:   property name containing gpio specifier(s)
  91  *
  92  * The function returns the count of GPIOs specified for a node.
  93  * Note that the empty GPIO specifiers count too. Returns either
  94  *   Number of gpios defined in property,
  95  *   -EINVAL for an incorrectly formed gpios property, or
  96  *   -ENOENT for a missing gpios property
  97  *
  98  * Example:
  99  * gpios = <0
 100  *          &gpio1 1 2
 101  *          0
 102  *          &gpio2 3 4>;
 103  *
 104  * The above example defines four GPIOs, two of which are not specified.
 105  * This function will return '4'
 106  */
 107 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
 108 {
 109         return of_count_phandle_with_args(np, propname, "#gpio-cells");
 110 }
 111
 112 /**
 113  * of_gpio_count() - Count GPIOs for a device
 114  * @np:         device node to count GPIOs for
 115  *
 116  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
 117  */
 118 static inline int of_gpio_count(struct device_node *np)
 119 {
 120         return of_gpio_named_count(np, "gpios");
 121 }
 122
 123 static inline int of_get_gpio_flags(struct device_node *np, int index,
 124                       enum of_gpio_flags *flags)
 125 {
 126         return of_get_named_gpio_flags(np, "gpios", index, flags);
 127 }
 128
 129 /**
 130  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
 131  * @np:         device node to get GPIO from
 132  * @propname:   Name of property containing gpio specifier(s)
 133  * @index:      index of the GPIO
 134  *
 135  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 136  * value on the error condition.
 137  */
 138 static inline int of_get_named_gpio(struct device_node *np,
 139                                    const char *propname, int index)
 140 {
 141         return of_get_named_gpio_flags(np, propname, index, NULL);
 142 }
 143
 144 /**
 145  * of_get_gpio() - Get a GPIO number to use with GPIO API
 146  * @np:         device node to get GPIO from
 147  * @index:      index of the GPIO
 148  *
 149  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
 150  * value on the error condition.
 151  */
 152 static inline int of_get_gpio(struct device_node *np, int index)
 153 {
 154         return of_get_gpio_flags(np, index, NULL);
 155 }
 156
 157 #endif /* __LINUX_OF_GPIO_H */