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#include <linux/gpio/consumer.h>
23
24struct device_node;
25
26/*
27 * This is Linux-specific flags. By default controllers' and Linux' mapping
28 * match, but GPIO controllers are free to translate their own flags to
29 * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
30 */
31enum of_gpio_flags {
32 OF_GPIO_ACTIVE_LOW = 0x1,
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 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
52 const char *list_name, int index, enum of_gpio_flags *flags);
53
54extern int of_mm_gpiochip_add(struct device_node *np,
55 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 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
67 const char *list_name, int index, enum of_gpio_flags *flags)
68{
69 return ERR_PTR(-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
84static inline int of_get_named_gpio_flags(struct device_node *np,
85 const char *list_name, int index, enum of_gpio_flags *flags)
86{
87 struct gpio_desc *desc;
88 desc = of_get_named_gpiod_flags(np, list_name, index, flags);
89
90 if (IS_ERR(desc))
91 return PTR_ERR(desc);
92 else
93 return desc_to_gpio(desc);
94}
95
96/**
97 * of_gpio_named_count() - Count GPIOs for a device
98 * @np: device node to count GPIOs for
99 * @propname: property name containing gpio specifier(s)
100 *
101 * The function returns the count of GPIOs specified for a node.
102 * Note that the empty GPIO specifiers count too. Returns either
103 * Number of gpios defined in property,
104 * -EINVAL for an incorrectly formed gpios property, or
105 * -ENOENT for a missing gpios property
106 *
107 * Example:
108 * gpios = <0
109 * &gpio1 1 2
110 * 0
111 * &gpio2 3 4>;
112 *
113 * The above example defines four GPIOs, two of which are not specified.
114 * This function will return '4'
115 */
116static inline int of_gpio_named_count(struct device_node *np, const char* propname)
117{
118 return of_count_phandle_with_args(np, propname, "#gpio-cells");
119}
120
121/**
122 * of_gpio_count() - Count GPIOs for a device
123 * @np: device node to count GPIOs for
124 *
125 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
126 */
127static inline int of_gpio_count(struct device_node *np)
128{
129 return of_gpio_named_count(np, "gpios");
130}
131
132/**
133 * of_get_gpiod_flags() - Get a GPIO descriptor and flags to use with GPIO API
134 * @np: device node to get GPIO from
135 * @index: index of the GPIO
136 * @flags: a flags pointer to fill in
137 *
138 * Returns GPIO descriptor to use with Linux generic GPIO API, or a errno
139 * value on the error condition. If @flags is not NULL the function also fills
140 * in flags for the GPIO.
141 */
142static inline struct gpio_desc *of_get_gpiod_flags(struct device_node *np,
143 int index, enum of_gpio_flags *flags)
144{
145 return of_get_named_gpiod_flags(np, "gpios", index, flags);
146}
147
148static inline int of_get_gpio_flags(struct device_node *np, int index,
149 enum of_gpio_flags *flags)
150{
151 return of_get_named_gpio_flags(np, "gpios", index, flags);
152}
153
154/**
155 * of_get_named_gpio() - Get a GPIO number to use with GPIO API
156 * @np: device node to get GPIO from
157 * @propname: Name of property containing gpio specifier(s)
158 * @index: index of the GPIO
159 *
160 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
161 * value on the error condition.
162 */
163static inline int of_get_named_gpio(struct device_node *np,
164 const char *propname, int index)
165{
166 return of_get_named_gpio_flags(np, propname, index, NULL);
167}
168
169/**
170 * of_get_gpio() - Get a GPIO number to use with GPIO API
171 * @np: device node to get GPIO from
172 * @index: index of the GPIO
173 *
174 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
175 * value on the error condition.
176 */
177static inline int of_get_gpio(struct device_node *np, int index)
178{
179 return of_get_gpio_flags(np, index, NULL);
180}
181
182#endif /* __LINUX_OF_GPIO_H */