of_gpio.h revision 15c9a0acc3f7873db4b7d35d016729b2dc229b49
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 unsigned int of_gpio_count(struct device_node *np);
54
55extern int of_mm_gpiochip_add(struct device_node *np,
56			      struct of_mm_gpio_chip *mm_gc);
57
58extern void of_gpiochip_add(struct gpio_chip *gc);
59extern void of_gpiochip_remove(struct gpio_chip *gc);
60extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
61extern int of_gpio_simple_xlate(struct gpio_chip *gc,
62				const struct of_phandle_args *gpiospec,
63				u32 *flags);
64
65#else /* CONFIG_OF_GPIO */
66
67/* Drivers may not strictly depend on the GPIO support, so let them link. */
68static inline int of_get_named_gpio_flags(struct device_node *np,
69		const char *list_name, int index, enum of_gpio_flags *flags)
70{
71	return -ENOSYS;
72}
73
74static inline unsigned int of_gpio_count(struct device_node *np)
75{
76	return 0;
77}
78
79static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
80				       const struct of_phandle_args *gpiospec,
81				       u32 *flags)
82{
83	return -ENOSYS;
84}
85
86static inline void of_gpiochip_add(struct gpio_chip *gc) { }
87static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
88
89#endif /* CONFIG_OF_GPIO */
90
91/**
92 * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
93 * @np:		device node to get GPIO from
94 * @index:	index of the GPIO
95 * @flags:	a flags pointer to fill in
96 *
97 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
98 * value on the error condition. If @flags is not NULL the function also fills
99 * in flags for the GPIO.
100 */
101static inline int of_get_gpio_flags(struct device_node *np, int index,
102		      enum of_gpio_flags *flags)
103{
104	return of_get_named_gpio_flags(np, "gpios", index, flags);
105}
106
107/**
108 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
109 * @np:		device node to get GPIO from
110 * @propname:	Name of property containing gpio specifier(s)
111 * @index:	index of the GPIO
112 *
113 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
114 * value on the error condition.
115 */
116static inline int of_get_named_gpio(struct device_node *np,
117                                   const char *propname, int index)
118{
119	return of_get_named_gpio_flags(np, propname, index, NULL);
120}
121
122/**
123 * of_get_gpio() - Get a GPIO number to use with GPIO API
124 * @np:		device node to get GPIO from
125 * @index:	index of the GPIO
126 *
127 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
128 * value on the error condition.
129 */
130static inline int of_get_gpio(struct device_node *np, int index)
131{
132	return of_get_gpio_flags(np, index, NULL);
133}
134
135#endif /* __LINUX_OF_GPIO_H */
136