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 OF_GPIO_OPEN_DRAIN = 0x4,
34 OF_GPIO_SLEEP_MAY_LOOSE_VALUE = 0x8,
35};
36
37#ifdef CONFIG_OF_GPIO
38
39/*
40 * OF GPIO chip for memory mapped banks
41 */
42struct 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
48static 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
53extern int of_get_named_gpio_flags(struct device_node *np,
54 const char *list_name, int index, enum of_gpio_flags *flags);
55
56extern int of_mm_gpiochip_add_data(struct device_node *np,
57 struct of_mm_gpio_chip *mm_gc,
58 void *data);
59static 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}
64extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
65
66extern 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. */
73static 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
82static 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 */
111static 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 */
122static inline int of_gpio_count(struct device_node *np)
123{
124 return of_gpio_named_count(np, "gpios");
125}
126
127static 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 */
142static 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 */
156static 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 */