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_named_count(struct device_node *np,
54					const char* propname);
55
56extern int of_mm_gpiochip_add(struct device_node *np,
57			      struct of_mm_gpio_chip *mm_gc);
58
59extern void of_gpiochip_add(struct gpio_chip *gc);
60extern void of_gpiochip_remove(struct gpio_chip *gc);
61extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
62extern int of_gpio_simple_xlate(struct gpio_chip *gc,
63				const struct of_phandle_args *gpiospec,
64				u32 *flags);
65
66#else /* CONFIG_OF_GPIO */
67
68/* Drivers may not strictly depend on the GPIO support, so let them link. */
69static inline int of_get_named_gpio_flags(struct device_node *np,
70		const char *list_name, int index, enum of_gpio_flags *flags)
71{
72	return -ENOSYS;
73}
74
75static inline unsigned int of_gpio_named_count(struct device_node *np,
76					const char* propname)
77{
78	return 0;
79}
80
81static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
82				       const struct of_phandle_args *gpiospec,
83				       u32 *flags)
84{
85	return -ENOSYS;
86}
87
88static inline void of_gpiochip_add(struct gpio_chip *gc) { }
89static inline void of_gpiochip_remove(struct gpio_chip *gc) { }
90
91#endif /* CONFIG_OF_GPIO */
92
93/**
94 * of_gpio_count - Count GPIOs for a device
95 * @np:		device node to count GPIOs for
96 *
97 * The function returns the count of GPIOs specified for a node.
98 *
99 * Note that the empty GPIO specifiers counts too. For example,
100 *
101 * gpios = <0
102 *          &pio1 1 2
103 *          0
104 *          &pio2 3 4>;
105 *
106 * defines four GPIOs (so this function will return 4), two of which
107 * are not specified.
108 */
109static inline unsigned int of_gpio_count(struct device_node *np)
110{
111	return of_gpio_named_count(np, "gpios");
112}
113
114/**
115 * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API
116 * @np:		device node to get GPIO from
117 * @index:	index of the GPIO
118 * @flags:	a flags pointer to fill in
119 *
120 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
121 * value on the error condition. If @flags is not NULL the function also fills
122 * in flags for the GPIO.
123 */
124static inline int of_get_gpio_flags(struct device_node *np, int index,
125		      enum of_gpio_flags *flags)
126{
127	return of_get_named_gpio_flags(np, "gpios", index, flags);
128}
129
130/**
131 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
132 * @np:		device node to get GPIO from
133 * @propname:	Name of property containing gpio specifier(s)
134 * @index:	index of the GPIO
135 *
136 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
137 * value on the error condition.
138 */
139static inline int of_get_named_gpio(struct device_node *np,
140                                   const char *propname, int index)
141{
142	return of_get_named_gpio_flags(np, propname, index, NULL);
143}
144
145/**
146 * of_get_gpio() - Get a GPIO number to use with GPIO API
147 * @np:		device node to get GPIO from
148 * @index:	index of the GPIO
149 *
150 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
151 * value on the error condition.
152 */
153static inline int of_get_gpio(struct device_node *np, int index)
154{
155	return of_get_gpio_flags(np, index, NULL);
156}
157
158#endif /* __LINUX_OF_GPIO_H */
159