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 OF_GPIO_OPEN_DRAIN = 0x4, 34 }; 35 36 #ifdef CONFIG_OF_GPIO 37 38 /* 39 * OF GPIO chip for memory mapped banks 40 */ 41 struct of_mm_gpio_chip { 42 struct gpio_chip gc; 43 void (*save_regs)(struct of_mm_gpio_chip *mm_gc); 44 void __iomem *regs; 45 }; 46 47 static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc) 48 { 49 return container_of(gc, struct of_mm_gpio_chip, gc); 50 } 51 52 extern int of_get_named_gpio_flags(struct device_node *np, 53 const char *list_name, int index, enum of_gpio_flags *flags); 54 55 extern int of_mm_gpiochip_add_data(struct device_node *np, 56 struct of_mm_gpio_chip *mm_gc, 57 void *data); 58 static inline int of_mm_gpiochip_add(struct device_node *np, 59 struct of_mm_gpio_chip *mm_gc) 60 { 61 return of_mm_gpiochip_add_data(np, mm_gc, NULL); 62 } 63 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc); 64 65 extern int of_gpio_simple_xlate(struct gpio_chip *gc, 66 const struct of_phandle_args *gpiospec, 67 u32 *flags); 68 69 #else /* CONFIG_OF_GPIO */ 70 71 /* Drivers may not strictly depend on the GPIO support, so let them link. */ 72 static inline int of_get_named_gpio_flags(struct device_node *np, 73 const char *list_name, int index, enum of_gpio_flags *flags) 74 { 75 if (flags) 76 *flags = 0; 77 78 return -ENOSYS; 79 } 80 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 88 #endif /* CONFIG_OF_GPIO */ 89 90 /** 91 * of_gpio_named_count() - Count GPIOs for a device 92 * @np: device node to count GPIOs for 93 * @propname: property name containing gpio specifier(s) 94 * 95 * The function returns the count of GPIOs specified for a node. 96 * Note that the empty GPIO specifiers count too. Returns either 97 * Number of gpios defined in property, 98 * -EINVAL for an incorrectly formed gpios property, or 99 * -ENOENT for a missing gpios property 100 * 101 * Example: 102 * gpios = <0 103 * &gpio1 1 2 104 * 0 105 * &gpio2 3 4>; 106 * 107 * The above example defines four GPIOs, two of which are not specified. 108 * This function will return '4' 109 */ 110 static inline int of_gpio_named_count(struct device_node *np, const char* propname) 111 { 112 return of_count_phandle_with_args(np, propname, "#gpio-cells"); 113 } 114 115 /** 116 * of_gpio_count() - Count GPIOs for a device 117 * @np: device node to count GPIOs for 118 * 119 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property 120 */ 121 static inline int of_gpio_count(struct device_node *np) 122 { 123 return of_gpio_named_count(np, "gpios"); 124 } 125 126 static inline int of_get_gpio_flags(struct device_node *np, int index, 127 enum of_gpio_flags *flags) 128 { 129 return of_get_named_gpio_flags(np, "gpios", index, flags); 130 } 131 132 /** 133 * of_get_named_gpio() - Get a GPIO number to use with GPIO API 134 * @np: device node to get GPIO from 135 * @propname: Name of property containing gpio specifier(s) 136 * @index: index of the GPIO 137 * 138 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 139 * value on the error condition. 140 */ 141 static inline int of_get_named_gpio(struct device_node *np, 142 const char *propname, int index) 143 { 144 return of_get_named_gpio_flags(np, propname, index, NULL); 145 } 146 147 /** 148 * of_get_gpio() - Get a GPIO number to use with GPIO API 149 * @np: device node to get GPIO from 150 * @index: index of the GPIO 151 * 152 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 153 * value on the error condition. 154 */ 155 static inline int of_get_gpio(struct device_node *np, int index) 156 { 157 return of_get_gpio_flags(np, index, NULL); 158 } 159 160 #endif /* __LINUX_OF_GPIO_H */ 161