d449991c4d
This commit adds support for configuring the pull-up and pull-down resistors available in some GPIO controllers. While configuring pull-up/pull-down is already possible through the pinctrl subsystem, some GPIO controllers, especially simple ones such as GPIO expanders on I2C, don't have any pinmuxing capability and therefore do not use the pinctrl subsystem. This commit implements the GPIO_PULL_UP and GPIO_PULL_DOWN flags, which can be used from the Device Tree, to enable a pull-up or pull-down resistor on a given GPIO. The flag is simply propagated all the way to the core GPIO subsystem, where it is used to call the gpio_chip ->set_config callback with the appropriate existing PIN_CONFIG_BIAS_* values. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
160 lines
4.2 KiB
C
160 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* OF helpers for the GPIO API
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*
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* Copyright (c) 2007-2008 MontaVista Software, Inc.
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*
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* Author: Anton Vorontsov <avorontsov@ru.mvista.com>
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*/
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#ifndef __LINUX_OF_GPIO_H
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#define __LINUX_OF_GPIO_H
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#include <linux/compiler.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/gpio.h>
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#include <linux/of.h>
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struct device_node;
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/*
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* This is Linux-specific flags. By default controllers' and Linux' mapping
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* match, but GPIO controllers are free to translate their own flags to
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* Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
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*/
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enum of_gpio_flags {
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OF_GPIO_ACTIVE_LOW = 0x1,
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OF_GPIO_SINGLE_ENDED = 0x2,
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OF_GPIO_OPEN_DRAIN = 0x4,
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OF_GPIO_TRANSITORY = 0x8,
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OF_GPIO_PULL_UP = 0x10,
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OF_GPIO_PULL_DOWN = 0x20,
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};
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#ifdef CONFIG_OF_GPIO
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/*
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* OF GPIO chip for memory mapped banks
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*/
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struct of_mm_gpio_chip {
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struct gpio_chip gc;
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void (*save_regs)(struct of_mm_gpio_chip *mm_gc);
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void __iomem *regs;
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};
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static inline struct of_mm_gpio_chip *to_of_mm_gpio_chip(struct gpio_chip *gc)
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{
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return container_of(gc, struct of_mm_gpio_chip, gc);
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}
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extern int of_get_named_gpio_flags(struct device_node *np,
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const char *list_name, int index, enum of_gpio_flags *flags);
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extern int of_mm_gpiochip_add_data(struct device_node *np,
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struct of_mm_gpio_chip *mm_gc,
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void *data);
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static inline int of_mm_gpiochip_add(struct device_node *np,
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struct of_mm_gpio_chip *mm_gc)
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{
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return of_mm_gpiochip_add_data(np, mm_gc, NULL);
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}
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extern void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc);
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extern int of_gpio_simple_xlate(struct gpio_chip *gc,
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const struct of_phandle_args *gpiospec,
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u32 *flags);
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#else /* CONFIG_OF_GPIO */
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/* Drivers may not strictly depend on the GPIO support, so let them link. */
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static inline int of_get_named_gpio_flags(struct device_node *np,
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const char *list_name, int index, enum of_gpio_flags *flags)
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{
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if (flags)
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*flags = 0;
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return -ENOSYS;
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}
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static inline int of_gpio_simple_xlate(struct gpio_chip *gc,
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const struct of_phandle_args *gpiospec,
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u32 *flags)
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{
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return -ENOSYS;
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}
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#endif /* CONFIG_OF_GPIO */
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/**
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* of_gpio_named_count() - Count GPIOs for a device
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* @np: device node to count GPIOs for
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* @propname: property name containing gpio specifier(s)
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*
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* The function returns the count of GPIOs specified for a node.
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* Note that the empty GPIO specifiers count too. Returns either
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* Number of gpios defined in property,
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* -EINVAL for an incorrectly formed gpios property, or
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* -ENOENT for a missing gpios property
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*
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* Example:
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* gpios = <0
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* &gpio1 1 2
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* 0
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* &gpio2 3 4>;
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*
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* The above example defines four GPIOs, two of which are not specified.
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* This function will return '4'
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*/
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static inline int of_gpio_named_count(struct device_node *np, const char* propname)
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{
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return of_count_phandle_with_args(np, propname, "#gpio-cells");
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}
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/**
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* of_gpio_count() - Count GPIOs for a device
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* @np: device node to count GPIOs for
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*
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* Same as of_gpio_named_count, but hard coded to use the 'gpios' property
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*/
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static inline int of_gpio_count(struct device_node *np)
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{
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return of_gpio_named_count(np, "gpios");
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}
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static inline int of_get_gpio_flags(struct device_node *np, int index,
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enum of_gpio_flags *flags)
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{
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return of_get_named_gpio_flags(np, "gpios", index, flags);
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}
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/**
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* of_get_named_gpio() - Get a GPIO number to use with GPIO API
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* @np: device node to get GPIO from
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* @propname: Name of property containing gpio specifier(s)
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* @index: index of the GPIO
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*
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* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
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* value on the error condition.
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*/
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static inline int of_get_named_gpio(struct device_node *np,
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const char *propname, int index)
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{
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return of_get_named_gpio_flags(np, propname, index, NULL);
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}
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/**
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* of_get_gpio() - Get a GPIO number to use with GPIO API
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* @np: device node to get GPIO from
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* @index: index of the GPIO
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*
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* Returns GPIO number to use with Linux generic GPIO API, or one of the errno
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* value on the error condition.
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*/
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static inline int of_get_gpio(struct device_node *np, int index)
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{
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return of_get_gpio_flags(np, index, NULL);
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}
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#endif /* __LINUX_OF_GPIO_H */
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