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