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 OF_GPIO_SINGLE_ENDED = 0x2, 33 }; 34 35 #ifdef CONFIG_OF_GPIO 36 37 /* 38 * OF GPIO chip for memory mapped banks 39 */ 40 struct 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 46 static 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 51 extern int of_get_named_gpio_flags(struct device_node *np, 52 const char *list_name, int index, enum of_gpio_flags *flags); 53 54 extern int of_mm_gpiochip_add(struct device_node *np, 55 struct of_mm_gpio_chip *mm_gc); 56 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc); 57 58 extern int of_gpiochip_add(struct gpio_chip *gc); 59 extern void of_gpiochip_remove(struct gpio_chip *gc); 60 extern int of_gpio_simple_xlate(struct gpio_chip *gc, 61 const struct of_phandle_args *gpiospec, 62 u32 *flags); 63 64 #else /* CONFIG_OF_GPIO */ 65 66 /* Drivers may not strictly depend on the GPIO support, so let them link. */ 67 static inline int of_get_named_gpio_flags(struct device_node *np, 68 const char *list_name, int index, enum of_gpio_flags *flags) 69 { 70 return -ENOSYS; 71 } 72 73 static inline int of_gpio_simple_xlate(struct gpio_chip *gc, 74 const struct of_phandle_args *gpiospec, 75 u32 *flags) 76 { 77 return -ENOSYS; 78 } 79 80 static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; } 81 static inline void of_gpiochip_remove(struct gpio_chip *gc) { } 82 83 #endif /* CONFIG_OF_GPIO */ 84 85 /** 86 * of_gpio_named_count() - Count GPIOs for a device 87 * @np: device node to count GPIOs for 88 * @propname: property name containing gpio specifier(s) 89 * 90 * The function returns the count of GPIOs specified for a node. 91 * Note that the empty GPIO specifiers count too. Returns either 92 * Number of gpios defined in property, 93 * -EINVAL for an incorrectly formed gpios property, or 94 * -ENOENT for a missing gpios property 95 * 96 * Example: 97 * gpios = <0 98 * &gpio1 1 2 99 * 0 100 * &gpio2 3 4>; 101 * 102 * The above example defines four GPIOs, two of which are not specified. 103 * This function will return '4' 104 */ 105 static inline int of_gpio_named_count(struct device_node *np, const char* propname) 106 { 107 return of_count_phandle_with_args(np, propname, "#gpio-cells"); 108 } 109 110 /** 111 * of_gpio_count() - Count GPIOs for a device 112 * @np: device node to count GPIOs for 113 * 114 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property 115 */ 116 static inline int of_gpio_count(struct device_node *np) 117 { 118 return of_gpio_named_count(np, "gpios"); 119 } 120 121 static inline int of_get_gpio_flags(struct device_node *np, int index, 122 enum of_gpio_flags *flags) 123 { 124 return of_get_named_gpio_flags(np, "gpios", index, flags); 125 } 126 127 /** 128 * of_get_named_gpio() - Get a GPIO number to use with GPIO API 129 * @np: device node to get GPIO from 130 * @propname: Name of property containing gpio specifier(s) 131 * @index: index of the GPIO 132 * 133 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 134 * value on the error condition. 135 */ 136 static inline int of_get_named_gpio(struct device_node *np, 137 const char *propname, int index) 138 { 139 return of_get_named_gpio_flags(np, propname, index, NULL); 140 } 141 142 /** 143 * of_get_gpio() - Get a GPIO number to use with GPIO API 144 * @np: device node to get GPIO from 145 * @index: index of the GPIO 146 * 147 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 148 * value on the error condition. 149 */ 150 static inline int of_get_gpio(struct device_node *np, int index) 151 { 152 return of_get_gpio_flags(np, index, NULL); 153 } 154 155 #endif /* __LINUX_OF_GPIO_H */ 156