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_data(struct device_node *np, 55 struct of_mm_gpio_chip *mm_gc, 56 void *data); 57 static inline int of_mm_gpiochip_add(struct device_node *np, 58 struct of_mm_gpio_chip *mm_gc) 59 { 60 return of_mm_gpiochip_add_data(np, mm_gc, NULL); 61 } 62 extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc); 63 64 extern int of_gpiochip_add(struct gpio_chip *gc); 65 extern void of_gpiochip_remove(struct gpio_chip *gc); 66 extern int of_gpio_simple_xlate(struct gpio_chip *gc, 67 const struct of_phandle_args *gpiospec, 68 u32 *flags); 69 70 #else /* CONFIG_OF_GPIO */ 71 72 /* Drivers may not strictly depend on the GPIO support, so let them link. */ 73 static inline int of_get_named_gpio_flags(struct device_node *np, 74 const char *list_name, int index, enum of_gpio_flags *flags) 75 { 76 if (flags) 77 *flags = 0; 78 79 return -ENOSYS; 80 } 81 82 static inline int of_gpio_simple_xlate(struct gpio_chip *gc, 83 const struct of_phandle_args *gpiospec, 84 u32 *flags) 85 { 86 return -ENOSYS; 87 } 88 89 static inline int of_gpiochip_add(struct gpio_chip *gc) { return 0; } 90 static inline void of_gpiochip_remove(struct gpio_chip *gc) { } 91 92 #endif /* CONFIG_OF_GPIO */ 93 94 /** 95 * of_gpio_named_count() - Count GPIOs for a device 96 * @np: device node to count GPIOs for 97 * @propname: property name containing gpio specifier(s) 98 * 99 * The function returns the count of GPIOs specified for a node. 100 * Note that the empty GPIO specifiers count too. Returns either 101 * Number of gpios defined in property, 102 * -EINVAL for an incorrectly formed gpios property, or 103 * -ENOENT for a missing gpios property 104 * 105 * Example: 106 * gpios = <0 107 * &gpio1 1 2 108 * 0 109 * &gpio2 3 4>; 110 * 111 * The above example defines four GPIOs, two of which are not specified. 112 * This function will return '4' 113 */ 114 static inline int of_gpio_named_count(struct device_node *np, const char* propname) 115 { 116 return of_count_phandle_with_args(np, propname, "#gpio-cells"); 117 } 118 119 /** 120 * of_gpio_count() - Count GPIOs for a device 121 * @np: device node to count GPIOs for 122 * 123 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property 124 */ 125 static inline int of_gpio_count(struct device_node *np) 126 { 127 return of_gpio_named_count(np, "gpios"); 128 } 129 130 static inline int of_get_gpio_flags(struct device_node *np, int index, 131 enum of_gpio_flags *flags) 132 { 133 return of_get_named_gpio_flags(np, "gpios", index, flags); 134 } 135 136 /** 137 * of_get_named_gpio() - Get a GPIO number to use with GPIO API 138 * @np: device node to get GPIO from 139 * @propname: Name of property containing gpio specifier(s) 140 * @index: index of the GPIO 141 * 142 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 143 * value on the error condition. 144 */ 145 static inline int of_get_named_gpio(struct device_node *np, 146 const char *propname, int index) 147 { 148 return of_get_named_gpio_flags(np, propname, index, NULL); 149 } 150 151 /** 152 * of_get_gpio() - Get a GPIO number to use with GPIO API 153 * @np: device node to get GPIO from 154 * @index: index of the GPIO 155 * 156 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 157 * value on the error condition. 158 */ 159 static inline int of_get_gpio(struct device_node *np, int index) 160 { 161 return of_get_gpio_flags(np, index, NULL); 162 } 163 164 #endif /* __LINUX_OF_GPIO_H */ 165