mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-11-15 01:17:39 +00:00
1bbd28d215
This function should also be part of the GPIO API, so add it. Signed-off-by: Simon Glass <sjg@chromium.org>
106 lines
3.1 KiB
C
106 lines
3.1 KiB
C
/*
|
|
* Copyright (c) 2011 The Chromium OS Authors.
|
|
* Copyright (c) 2011, NVIDIA Corp. All rights reserved.
|
|
* See file CREDITS for list of people who contributed to this
|
|
* project.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation; either version 2 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
|
* MA 02111-1307 USA
|
|
*/
|
|
|
|
#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 ownership of a GPIO.
|
|
*
|
|
* @param gpio GPIO number
|
|
* @param label Name given to the 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);
|
|
|
|
/**
|
|
* 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);
|
|
#endif /* _ASM_GENERIC_GPIO_H_ */
|