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
23 struct 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 */
30 enum 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 */
39 struct 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
to_of_mm_gpio_chip(struct gpio_chip * gc)45 static 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
50 extern int of_get_named_gpio_flags(struct device_node *np,
51 const char *list_name, int index, enum of_gpio_flags *flags);
52
53 extern unsigned int of_gpio_named_count(struct device_node *np,
54 const char* propname);
55
56 extern int of_mm_gpiochip_add(struct device_node *np,
57 struct of_mm_gpio_chip *mm_gc);
58
59 extern void of_gpiochip_add(struct gpio_chip *gc);
60 extern void of_gpiochip_remove(struct gpio_chip *gc);
61 extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
62 extern 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. */
of_get_named_gpio_flags(struct device_node * np,const char * list_name,int index,enum of_gpio_flags * flags)69 static 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
of_gpio_named_count(struct device_node * np,const char * propname)75 static inline unsigned int of_gpio_named_count(struct device_node *np,
76 const char* propname)
77 {
78 return 0;
79 }
80
of_gpio_simple_xlate(struct gpio_chip * gc,const struct of_phandle_args * gpiospec,u32 * flags)81 static 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
of_gpiochip_add(struct gpio_chip * gc)88 static inline void of_gpiochip_add(struct gpio_chip *gc) { }
of_gpiochip_remove(struct gpio_chip * gc)89 static 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 */
of_gpio_count(struct device_node * np)109 static 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 */
of_get_gpio_flags(struct device_node * np,int index,enum of_gpio_flags * flags)124 static 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 */
of_get_named_gpio(struct device_node * np,const char * propname,int index)139 static 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 */
of_get_gpio(struct device_node * np,int index)153 static 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