mirror of
https://github.com/smaeul/u-boot.git
synced 2025-10-31 03:58:17 +00:00
9d2cb8e8e6
Since we want want to have a standard GPIO interface, this adds a definition for this into include/asm-generic/gpio.h. Signed-off-by: Simon Glass <sjg@chromium.org>
75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
/*
|
|
* Copyright (c) 2011 The Chromium OS Authors.
|
|
* 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
|
|
*/
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
|
|
/**
|
|
* Make a GPIO an input.
|
|
*
|
|
* @param gp GPIO number
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_direction_input(int gp);
|
|
|
|
/**
|
|
* Make a GPIO an output, and set its value.
|
|
*
|
|
* @param gp GPIO number
|
|
* @param value GPIO value (0 for low or 1 for high)
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_direction_output(int gp, int value);
|
|
|
|
/**
|
|
* Get a GPIO's value. This will work whether the GPIO is an input
|
|
* or an output.
|
|
*
|
|
* @param gp GPIO number
|
|
* @return 0 if low, 1 if high, -1 on error
|
|
*/
|
|
int gpio_get_value(int gp);
|
|
|
|
/**
|
|
* Set an output GPIO's value. The GPIO must already be an output of
|
|
* this function may have no effect.
|
|
*
|
|
* @param gp GPIO number
|
|
* @param value GPIO value (0 for low or 1 for high)
|
|
* @return 0 if ok, -1 on error
|
|
*/
|
|
int gpio_set_value(int gp, int value);
|