nymea/libnymea/hardware/pwm.h

111 lines
3.4 KiB
C++

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* *
* Copyright (C) 2015 -2016 Simon Stürz <simon.stuerz@guh.io> *
* *
* This file is part of nymea. *
* *
* This library 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; either *
* version 2.1 of the License, or (at your option) any later version. *
* *
* This library 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 library; If not, see *
* <http://www.gnu.org/licenses/>. *
* *
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
#ifndef PWM_H
#define PWM_H
#include <QObject>
#include <QDebug>
#include <QFile>
#include <QDir>
#include "libnymea.h"
/* i.MX6 PWMs
*
* /sys/class/pwm/pwmchip0 -> pwm1 (npwm = 1)
* /sys/class/pwm/pwmchip1 -> pwm2 (npwm = 1)
* /sys/class/pwm/pwmchip2 -> pwm3 (npwm = 1)
* /sys/class/pwm/pwmchip3 -> pwm4 (npwm = 1)
*
* each chip has 1 pwm ( -> pwm0)
*
* example:
* echo 0 > /sys/class/pwm/pwmchip1/export
*
* ls -l /sys/class/pwm/pwmchip1/pwm0/
* duty_cycle => nano seconds active time
* enable => 0 = disable, 1 = enable
* period => nano seconds active + inactive
* polarity => "normal" or "inversed"
*
* |<--------- period --------->|
*
* |<--duty cycle -->|
* 1_ _________________ _________________ _____
* | | | | |
* 0_ _| |___________| |___________| .......
*
*/
class LIBNYMEA_EXPORT Pwm : public QObject
{
Q_OBJECT
public:
enum Polarity {
PolarityNormal,
PolarityInversed,
PolarityInvalid
};
explicit Pwm(int chipNumber, QObject *parent = nullptr);
~Pwm();
static bool isAvailable();
bool exportPwm();
bool enable();
bool disable();
bool isEnabled();
int chipNumber();
long period();
bool setPeriod(long nanoSeconds);
double frequency();
bool setFrequency(double kHz);
long dutyCycle();
bool setDutyCycle(long nanoSeconds);
Pwm::Polarity polarity();
bool setPolarity(Pwm::Polarity polarity);
int percentage();
bool setPercentage(int percentage);
private:
int m_chipNumber;
long m_period;
long m_dutyCycle;
QDir m_pwmDirectory;
bool unexportPwm();
};
QDebug operator<< (QDebug d, Pwm *pwm);
#endif // PWM_H