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 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 int of_mm_gpiochip_add(struct device_node *np, 54 struct of_mm_gpio_chip *mm_gc); 55 56 extern void of_gpiochip_add(struct gpio_chip *gc); 57 extern void of_gpiochip_remove(struct gpio_chip *gc); 58 extern int of_gpio_simple_xlate(struct gpio_chip *gc, 59 const struct of_phandle_args *gpiospec, 60 u32 *flags); 61 62 #else /* CONFIG_OF_GPIO */ 63 64 /* Drivers may not strictly depend on the GPIO support, so let them link. */ 65 static inline int of_get_named_gpio_flags(struct device_node *np, 66 const char *list_name, int index, enum of_gpio_flags *flags) 67 { 68 return -ENOSYS; 69 } 70 71 static inline int of_gpio_simple_xlate(struct gpio_chip *gc, 72 const struct of_phandle_args *gpiospec, 73 u32 *flags) 74 { 75 return -ENOSYS; 76 } 77 78 static inline void of_gpiochip_add(struct gpio_chip *gc) { } 79 static inline void of_gpiochip_remove(struct gpio_chip *gc) { } 80 81 #endif /* CONFIG_OF_GPIO */ 82 83 /** 84 * of_gpio_named_count() - Count GPIOs for a device 85 * @np: device node to count GPIOs for 86 * @propname: property name containing gpio specifier(s) 87 * 88 * The function returns the count of GPIOs specified for a node. 89 * Note that the empty GPIO specifiers count too. Returns either 90 * Number of gpios defined in property, 91 * -EINVAL for an incorrectly formed gpios property, or 92 * -ENOENT for a missing gpios property 93 * 94 * Example: 95 * gpios = <0 96 * &gpio1 1 2 97 * 0 98 * &gpio2 3 4>; 99 * 100 * The above example defines four GPIOs, two of which are not specified. 101 * This function will return '4' 102 */ 103 static inline int of_gpio_named_count(struct device_node *np, const char* propname) 104 { 105 return of_count_phandle_with_args(np, propname, "#gpio-cells"); 106 } 107 108 /** 109 * of_gpio_count() - Count GPIOs for a device 110 * @np: device node to count GPIOs for 111 * 112 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property 113 */ 114 static inline int of_gpio_count(struct device_node *np) 115 { 116 return of_gpio_named_count(np, "gpios"); 117 } 118 119 /** 120 * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API 121 * @np: device node to get GPIO from 122 * @index: index of the GPIO 123 * @flags: a flags pointer to fill in 124 * 125 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 126 * value on the error condition. If @flags is not NULL the function also fills 127 * in flags for the GPIO. 128 */ 129 static inline int of_get_gpio_flags(struct device_node *np, int index, 130 enum of_gpio_flags *flags) 131 { 132 return of_get_named_gpio_flags(np, "gpios", index, flags); 133 } 134 135 /** 136 * of_get_named_gpio() - Get a GPIO number to use with GPIO API 137 * @np: device node to get GPIO from 138 * @propname: Name of property containing gpio specifier(s) 139 * @index: index of the GPIO 140 * 141 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 142 * value on the error condition. 143 */ 144 static inline int of_get_named_gpio(struct device_node *np, 145 const char *propname, int index) 146 { 147 return of_get_named_gpio_flags(np, propname, index, NULL); 148 } 149 150 /** 151 * of_get_gpio() - Get a GPIO number to use with GPIO API 152 * @np: device node to get GPIO from 153 * @index: index of the GPIO 154 * 155 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 156 * value on the error condition. 157 */ 158 static inline int of_get_gpio(struct device_node *np, int index) 159 { 160 return of_get_gpio_flags(np, index, NULL); 161 } 162 163 #endif /* __LINUX_OF_GPIO_H */ 164