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 #include <linux/gpio/consumer.h> 23 24 struct device_node; 25 26 /* 27 * This is Linux-specific flags. By default controllers' and Linux' mapping 28 * match, but GPIO controllers are free to translate their own flags to 29 * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended. 30 */ 31 enum of_gpio_flags { 32 OF_GPIO_ACTIVE_LOW = 0x1, 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 struct gpio_desc *of_get_named_gpiod_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 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 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, 67 const char *list_name, int index, enum of_gpio_flags *flags) 68 { 69 return ERR_PTR(-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 static inline int of_get_named_gpio_flags(struct device_node *np, 85 const char *list_name, int index, enum of_gpio_flags *flags) 86 { 87 struct gpio_desc *desc; 88 desc = of_get_named_gpiod_flags(np, list_name, index, flags); 89 90 if (IS_ERR(desc)) 91 return PTR_ERR(desc); 92 else 93 return desc_to_gpio(desc); 94 } 95 96 /** 97 * of_gpio_named_count() - Count GPIOs for a device 98 * @np: device node to count GPIOs for 99 * @propname: property name containing gpio specifier(s) 100 * 101 * The function returns the count of GPIOs specified for a node. 102 * Note that the empty GPIO specifiers count too. Returns either 103 * Number of gpios defined in property, 104 * -EINVAL for an incorrectly formed gpios property, or 105 * -ENOENT for a missing gpios property 106 * 107 * Example: 108 * gpios = <0 109 * &gpio1 1 2 110 * 0 111 * &gpio2 3 4>; 112 * 113 * The above example defines four GPIOs, two of which are not specified. 114 * This function will return '4' 115 */ 116 static inline int of_gpio_named_count(struct device_node *np, const char* propname) 117 { 118 return of_count_phandle_with_args(np, propname, "#gpio-cells"); 119 } 120 121 /** 122 * of_gpio_count() - Count GPIOs for a device 123 * @np: device node to count GPIOs for 124 * 125 * Same as of_gpio_named_count, but hard coded to use the 'gpios' property 126 */ 127 static inline int of_gpio_count(struct device_node *np) 128 { 129 return of_gpio_named_count(np, "gpios"); 130 } 131 132 /** 133 * of_get_gpiod_flags() - Get a GPIO descriptor and flags to use with GPIO API 134 * @np: device node to get GPIO from 135 * @index: index of the GPIO 136 * @flags: a flags pointer to fill in 137 * 138 * Returns GPIO descriptor to use with Linux generic GPIO API, or a errno 139 * value on the error condition. If @flags is not NULL the function also fills 140 * in flags for the GPIO. 141 */ 142 static inline struct gpio_desc *of_get_gpiod_flags(struct device_node *np, 143 int index, enum of_gpio_flags *flags) 144 { 145 return of_get_named_gpiod_flags(np, "gpios", index, flags); 146 } 147 148 static inline int of_get_gpio_flags(struct device_node *np, int index, 149 enum of_gpio_flags *flags) 150 { 151 return of_get_named_gpio_flags(np, "gpios", index, flags); 152 } 153 154 /** 155 * of_get_named_gpio() - Get a GPIO number to use with GPIO API 156 * @np: device node to get GPIO from 157 * @propname: Name of property containing gpio specifier(s) 158 * @index: index of the GPIO 159 * 160 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 161 * value on the error condition. 162 */ 163 static inline int of_get_named_gpio(struct device_node *np, 164 const char *propname, int index) 165 { 166 return of_get_named_gpio_flags(np, propname, index, NULL); 167 } 168 169 /** 170 * of_get_gpio() - Get a GPIO number to use with GPIO API 171 * @np: device node to get GPIO from 172 * @index: index of the GPIO 173 * 174 * Returns GPIO number to use with Linux generic GPIO API, or one of the errno 175 * value on the error condition. 176 */ 177 static inline int of_get_gpio(struct device_node *np, int index) 178 { 179 return of_get_gpio_flags(np, index, NULL); 180 } 181 182 #endif /* __LINUX_OF_GPIO_H */ 183