Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
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
23struct 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 */
30enum 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 */
39struct 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
45static 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
50extern int of_get_named_gpio_flags(struct device_node *np,
51 const char *list_name, int index, enum of_gpio_flags *flags);
52
53extern int of_mm_gpiochip_add(struct device_node *np,
54 struct of_mm_gpio_chip *mm_gc);
55
56extern void of_gpiochip_add(struct gpio_chip *gc);
57extern void of_gpiochip_remove(struct gpio_chip *gc);
58extern int of_gpio_simple_xlate(struct gpio_chip *gc,
59 const struct of_phandle_args *gpiospec,
60 u32 *flags);
61
62#else /* CONFIG_OF_GPIO */
63
64/* Drivers may not strictly depend on the GPIO support, so let them link. */
65static inline int of_get_named_gpio_flags(struct device_node *np,
66 const char *list_name, int index, enum of_gpio_flags *flags)
67{
68 return -ENOSYS;
69}
70
71static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
72 const struct of_phandle_args *gpiospec,
73 u32 *flags)
74{
75 return -ENOSYS;
76}
77
78static inline void of_gpiochip_add(struct gpio_chip *gc) { }
79static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
80
81#endif /* CONFIG_OF_GPIO */
82
83/**
84 * of_gpio_named_count() - Count GPIOs for a device
85 * @np: device node to count GPIOs for
86 * @propname: property name containing gpio specifier(s)
87 *
88 * The function returns the count of GPIOs specified for a node.
89 * Note that the empty GPIO specifiers count too. Returns either
90 * Number of gpios defined in property,
91 * -EINVAL for an incorrectly formed gpios property, or
92 * -ENOENT for a missing gpios property
93 *
94 * Example:
95 * gpios = <0
96 * &gpio1 1 2
97 * 0
98 * &gpio2 3 4>;
99 *
100 * The above example defines four GPIOs, two of which are not specified.
101 * This function will return '4'
102 */
103static inline int of_gpio_named_count(struct device_node *np, const char* propname)
104{
105 return of_count_phandle_with_args(np, propname, "#gpio-cells");
106}
107
108/**
109 * of_gpio_count() - Count GPIOs for a device
110 * @np: device node to count GPIOs for
111 *
112 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
113 */
114static inline int of_gpio_count(struct device_node *np)
115{
116 return of_gpio_named_count(np, "gpios");
117}
118
119static inline int of_get_gpio_flags(struct device_node *np, int index,
120 enum of_gpio_flags *flags)
121{
122 return of_get_named_gpio_flags(np, "gpios", index, flags);
123}
124
125/**
126 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
127 * @np: device node to get GPIO from
128 * @propname: Name of property containing gpio specifier(s)
129 * @index: index of the GPIO
130 *
131 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
132 * value on the error condition.
133 */
134static inline int of_get_named_gpio(struct device_node *np,
135 const char *propname, int index)
136{
137 return of_get_named_gpio_flags(np, propname, index, NULL);
138}
139
140/**
141 * of_get_gpio() - Get a GPIO number to use with GPIO API
142 * @np: device node to get GPIO from
143 * @index: index of the GPIO
144 *
145 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
146 * value on the error condition.
147 */
148static inline int of_get_gpio(struct device_node *np, int index)
149{
150 return of_get_gpio_flags(np, index, NULL);
151}
152
153#endif /* __LINUX_OF_GPIO_H */