1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3  * OF helpers for the GPIO API
4  *
5  * Copyright (c) 2007-2008  MontaVista Software, Inc.
6  *
7  * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
8  */
9 
10 #ifndef __LINUX_OF_GPIO_H
11 #define __LINUX_OF_GPIO_H
12 
13 #include <linux/compiler.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/gpio.h>
17 #include <linux/of.h>
18 
19 struct device_node;
20 
21 /*
22  * This is Linux-specific flags. By default controllers' and Linux' mapping
23  * match, but GPIO controllers are free to translate their own flags to
24  * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
25  */
26 enum of_gpio_flags {
27 	OF_GPIO_ACTIVE_LOW = 0x1,
28 	OF_GPIO_SINGLE_ENDED = 0x2,
29 	OF_GPIO_OPEN_DRAIN = 0x4,
30 	OF_GPIO_TRANSITORY = 0x8,
31 };
32 
33 #ifdef CONFIG_OF_GPIO
34 
35 /*
36  * OF GPIO chip for memory mapped banks
37  */
38 struct of_mm_gpio_chip {
39 	struct gpio_chip gc;
40 	void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
41 	void __iomem *regs;
42 };
43 
to_of_mm_gpio_chip(struct gpio_chip * gc)44 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
45 {
46 	return container_of(gc, struct of_mm_gpio_chip, gc);
47 }
48 
49 extern int of_get_named_gpio_flags(struct device_node *np,
50 		const char *list_name, int index, enum of_gpio_flags *flags);
51 
52 extern int of_mm_gpiochip_add_data(struct device_node *np,
53 				   struct of_mm_gpio_chip *mm_gc,
54 				   void *data);
of_mm_gpiochip_add(struct device_node * np,struct of_mm_gpio_chip * mm_gc)55 static inline int of_mm_gpiochip_add(struct device_node *np,
56 				     struct of_mm_gpio_chip *mm_gc)
57 {
58 	return of_mm_gpiochip_add_data(np, mm_gc, NULL);
59 }
60 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
61 
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 	if (flags)
73 		*flags = 0;
74 
75 	return -ENOSYS;
76 }
77 
of_gpio_simple_xlate(struct gpio_chip * gc,const struct of_phandle_args * gpiospec,u32 * flags)78 static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
79 				       const struct of_phandle_args *gpiospec,
80 				       u32 *flags)
81 {
82 	return -ENOSYS;
83 }
84 
85 #endif /* CONFIG_OF_GPIO */
86 
87 /**
88  * of_gpio_named_count() - Count GPIOs for a device
89  * @np:		device node to count GPIOs for
90  * @propname:	property name containing gpio specifier(s)
91  *
92  * The function returns the count of GPIOs specified for a node.
93  * Note that the empty GPIO specifiers count too. Returns either
94  *   Number of gpios defined in property,
95  *   -EINVAL for an incorrectly formed gpios property, or
96  *   -ENOENT for a missing gpios property
97  *
98  * Example:
99  * gpios = <0
100  *          &gpio1 1 2
101  *          0
102  *          &gpio2 3 4>;
103  *
104  * The above example defines four GPIOs, two of which are not specified.
105  * This function will return '4'
106  */
of_gpio_named_count(struct device_node * np,const char * propname)107 static inline int of_gpio_named_count(struct device_node *np, const char* propname)
108 {
109 	return of_count_phandle_with_args(np, propname, "#gpio-cells");
110 }
111 
112 /**
113  * of_gpio_count() - Count GPIOs for a device
114  * @np:		device node to count GPIOs for
115  *
116  * Same as of_gpio_named_count, but hard coded to use the 'gpios' property
117  */
of_gpio_count(struct device_node * np)118 static inline int of_gpio_count(struct device_node *np)
119 {
120 	return of_gpio_named_count(np, "gpios");
121 }
122 
of_get_gpio_flags(struct device_node * np,int index,enum of_gpio_flags * flags)123 static inline int of_get_gpio_flags(struct device_node *np, int index,
124 		      enum of_gpio_flags *flags)
125 {
126 	return of_get_named_gpio_flags(np, "gpios", index, flags);
127 }
128 
129 /**
130  * of_get_named_gpio() - Get a GPIO number to use with GPIO API
131  * @np:		device node to get GPIO from
132  * @propname:	Name of property containing gpio specifier(s)
133  * @index:	index of the GPIO
134  *
135  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
136  * value on the error condition.
137  */
of_get_named_gpio(struct device_node * np,const char * propname,int index)138 static inline int of_get_named_gpio(struct device_node *np,
139                                    const char *propname, int index)
140 {
141 	return of_get_named_gpio_flags(np, propname, index, NULL);
142 }
143 
144 /**
145  * of_get_gpio() - Get a GPIO number to use with GPIO API
146  * @np:		device node to get GPIO from
147  * @index:	index of the GPIO
148  *
149  * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
150  * value on the error condition.
151  */
of_get_gpio(struct device_node * np,int index)152 static inline int of_get_gpio(struct device_node *np, int index)
153 {
154 	return of_get_gpio_flags(np, index, NULL);
155 }
156 
157 #endif /* __LINUX_OF_GPIO_H */
158