mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-04 18:41:03 +00:00
1a4596601f
Signed-off-by: Wolfgang Denk <wd@denx.de> [trini: Fixup common/cmd_io.c] Signed-off-by: Tom Rini <trini@ti.com>
81 lines
2.2 KiB
C
81 lines
2.2 KiB
C
/*
|
|
* Copyright (c) 2011 The Chromium OS Authors.
|
|
* Copyright (c) 2011, NVIDIA Corp. All rights reserved.
|
|
* SPDX-License-Identifier: GPL-2.0+
|
|
*/
|
|
|
|
#ifndef _ASM_GENERIC_GPIO_H_
|
|
#define _ASM_GENERIC_GPIO_H_
|
|
|
|
/*
|
|
* Generic GPIO API for U-Boot
|
|
*
|
|
* GPIOs are numbered from 0 to GPIO_COUNT-1 which value is defined
|
|
* by the SOC/architecture.
|
|
*
|
|
* Each GPIO can be an input or output. If an input then its value can
|
|
* be read as 0 or 1. If an output then its value can be set to 0 or 1.
|
|
* If you try to write an input then the value is undefined. If you try
|
|
* to read an output, barring something very unusual, you will get
|
|
* back the value of the output that you previously set.
|
|
*
|
|
* In some cases the operation may fail, for example if the GPIO number
|
|
* is out of range, or the GPIO is not available because its pin is
|
|
* being used by another function. In that case, functions may return
|
|
* an error value of -1.
|
|
*/
|
|
|
|
/**
|
|
* Request a gpio. This should be called before any of the other functions
|
|
* are used on this gpio.
|
|
*
|
|
* @param gp GPIO number
|
|
* @param label User label for this GPIO
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_request(unsigned gpio, const char *label);
|
|
|
|
/**
|
|
* Stop using the GPIO. This function should not alter pin configuration.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_free(unsigned gpio);
|
|
|
|
/**
|
|
* Make a GPIO an input.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_direction_input(unsigned gpio);
|
|
|
|
/**
|
|
* Make a GPIO an output, and set its value.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @param value GPIO value (0 for low or 1 for high)
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_direction_output(unsigned gpio, int value);
|
|
|
|
/**
|
|
* Get a GPIO's value. This will work whether the GPIO is an input
|
|
* or an output.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @return 0 if low, 1 if high, -1 on error
|
|
*/
|
|
int gpio_get_value(unsigned gpio);
|
|
|
|
/**
|
|
* Set an output GPIO's value. The GPIO must already be an output or
|
|
* this function may have no effect.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @param value GPIO value (0 for low or 1 for high)
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_set_value(unsigned gpio, int value);
|
|
#endif /* _ASM_GENERIC_GPIO_H_ */
|