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 unsigned int of_gpio_named_count(struct device_node *np, 54 const char* propname); 55 56 extern int of_mm_gpiochip_add(struct device_node *np, 57 struct of_mm_gpio_chip *mm_gc); 58 59 extern void of_gpiochip_add(struct gpio_chip *gc); 60 extern void of_gpiochip_remove(struct gpio_chip *gc); 61 extern int of_gpio_simple_xlate(struct gpio_chip *gc, 62 const struct of_phandle_args *gpiospec, 63 u32 *flags); 64 65 #else /* CONFIG_OF_GPIO */ 66 67 /* Drivers may not strictly depend on the GPIO support, so let them link. */ 68 static inline int of_get_named_gpio_flags(struct device_node *np, 69 const char *list_name, int index, enum of_gpio_flags *flags) 70 { 71 return -ENOSYS; 72 } 73 74 static inline unsigned int of_gpio_named_count(struct device_node *np, 75 const char* propname) 76 { 77 return 0; 78 } 79 80 static inline int of_gpio_simple_xlate(struct gpio_chip *gc, 81 const struct of_phandle_args *gpiospec, 82 u32 *flags) 83 { 84 return -ENOSYS; 85 } 86 87 static inline void of_gpiochip_add(struct gpio_chip *gc) { } 88 static inline void of_gpiochip_remove(struct gpio_chip *gc) { } 89 90 #endif /* CONFIG_OF_GPIO */ 91 92 /** 93 * of_gpio_count - Count GPIOs for a device 94 * @np: device node to count GPIOs for 95 * 96 * The function returns the count of GPIOs specified for a node. 97 * 98 * Note that the empty GPIO specifiers counts too. For example, 99 * 100 * gpios = <0 101 * &pio1 1 2 102 * 0 103 * &pio2 3 4>; 104 * 105 * defines four GPIOs (so this function will return 4), two of which 106 * are not specified. 107 */ 108 static inline unsigned int of_gpio_count(struct device_node *np) 109 { 110 return of_gpio_named_count(np, "gpios"); 111 } 112 113 /** 114 * of_get_gpio_flags() - Get a GPIO number and flags to use with GPIO API 115 * @np: device node to get GPIO from 116 * @index: index of the GPIO 117 * @flags: a flags pointer to fill in 118 * 119 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 120 * value on the error condition. If @flags is not NULL the function also fills 121 * in flags for the GPIO. 122 */ 123 static inline int of_get_gpio_flags(struct device_node *np, int index, 124 enum of_gpio_flags *flags) 125 { 126 return of_get_named_gpio_flags(np, "gpios", index, flags); 127 } 128 129 /** 130 * of_get_named_gpio() - Get a GPIO number to use with GPIO API 131 * @np: device node to get GPIO from 132 * @propname: Name of property containing gpio specifier(s) 133 * @index: index of the GPIO 134 * 135 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 136 * value on the error condition. 137 */ 138 static inline int of_get_named_gpio(struct device_node *np, 139 const char *propname, int index) 140 { 141 return of_get_named_gpio_flags(np, propname, index, NULL); 142 } 143 144 /** 145 * of_get_gpio() - Get a GPIO number to use with GPIO API 146 * @np: device node to get GPIO from 147 * @index: index of the GPIO 148 * 149 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 150 * value on the error condition. 151 */ 152 static inline int of_get_gpio(struct device_node *np, int index) 153 { 154 return of_get_gpio_flags(np, index, NULL); 155 } 156 157 #endif /* __LINUX_OF_GPIO_H */ 158