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