regulator.c

/*
        Thymio-II Firmware

        Copyright (C) 2011 Philippe Retornaz <philippe dot retornaz at epfl dot ch>,
        Mobots group (http://mobots.epfl.ch), Robotics system laboratory (http://lsro.epfl.ch)
        EPFL Ecole polytechnique federale de Lausanne (http://www.epfl.ch)

        See authors.txt for more details about other contributors.

        This program is free software: you can redistribute it and/or modify
        it under the terms of the GNU Lesser General Public License as published
        by the Free Software Foundation, version 3 of the License.

        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 Lesser General Public License for more details.

        You should have received a copy of the GNU Lesser General Public License
        along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#include "regulator.h"

#include <types/types.h>

static unsigned int refcount;

// There is a thiny race window when VA is disabled, and at the same time is preempted by a va_get
void va_get(void) {
	atomic_add(&refcount,1);
	VA_ENABLE = 1;
}

void va_put(void) {
	if(!atomic_add_and_test(&refcount, -1))
		VA_ENABLE = 0;	
}