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