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/**
* @file priv_gpio.h
* GPIO access for unpriviledged processes
*
* Copyright (C) 2018 Clyne Sullivan
*
* 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 3 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, see <https://www.gnu.org/licenses/>.
*/
#ifndef PRIV_GPIO_H_
#define PRIV_GPIO_H_
// For value flags
#include <kernel/gpio.h>
/**
* Possible GPIO calls.
*/
enum GPIO_CALLS {
GPIO_MODE = 0, /**< Change GPIO mode */
GPIO_TYPE, /**< Change GPIO type (PuPd/ODrain) */
GPIO_PUPD, /**< Set/clear pullup/pulldown */
GPIO_SPEED, /**< Set GPIO speed */
GPIO_OUT, /**< Set GPIO output state */
};
/**
* Provides unpriviledged GPIO access.
* @param call The type of GPIO call to make
* @param pin The pin to modify (0-15 = A, 16-31 = B, ...)
* @param value The value to pass to the call
*/
void gpio(uint32_t call, uint32_t pin, uint32_t value)
{
register uint32_t r0 asm("r0") = call;
register uint32_t r1 asm("r1") = pin;
register uint32_t r2 asm("r2") = value;
asm("\
mov r0, %0; \
mov r1, %1; \
mov r2, %2; \
svc 1; \
" :: "r" (r0), "r" (r1), "r" (r2));
}
#endif // PRIV_GPIO_H_
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