/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
*
* Copyright 2013 - 2020, nymea GmbH
* Contact: contact@nymea.io
*
* This file is part of nymea.
* This project including source code and documentation is protected by
* copyright law, and remains the property of nymea GmbH. All rights, including
* reproduction, publication, editing and translation, are reserved. The use of
* this project is subject to the terms of a license agreement to be concluded
* with nymea GmbH in accordance with the terms of use of nymea GmbH, available
* under https://nymea.io/license
*
* GNU Lesser General Public License Usage
* Alternatively, this project may be redistributed and/or modified under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; version 3. This project 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 project. If not, see <https://www.gnu.org/licenses/>.
*
* For any further details and any questions please contact us under
* contact@nymea.io or see our FAQ/Licensing Information on
* https://nymea.io/license/faq
*
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#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