Implement min PWM finding logic

app/src/fan/HwmonFan.cxx

@@ -1,20 +1,59 @@
+#include <chrono>
+#include <iostream>
+#include <ostream>
+#include <thread>
+
 #include "pwm/PWMControl.h"
 #include <boost/json/object.hpp>
 #include <fan/HwmonFan.h>
 
+#define TIMEOUT 5
+
 using namespace std;
 
-HwmonFan::HwmonFan(shared_ptr<PWMControl> pwmControl,
-                   shared_ptr<Sensor> rpmSensor)
-    : mPWMControl(pwmControl), mRpmSensor(rpmSensor) {}
+HwmonFan::HwmonFan(std::shared_ptr<PWMControl> pwmControl,
+                   std::shared_ptr<Sensor> rpmSensor, std::string label,
+                   int minPWM, int startPWM)
+    : mPWMControl(pwmControl), mRpmSensor(rpmSensor), mLabel(label),
+      mMinPWM(minPWM), mStartPWM(startPWM) {
+  mPWMControl->EnableManualControl();
+}
 
-void HwmonFan::pwm(int percent) { mPWMControl->pwm(percent); }
+void HwmonFan::PWM(int percent) { mPWMControl->pwm(percent); }
 
-int HwmonFan::rpm() { return mRpmSensor->value(); }
+int HwmonFan::RPM() { return mRpmSensor->value(); }
+
+void HwmonFan::FindMinPWM() {
+  int minPWM = 0;
+
+  for (int curPWM = 100; curPWM > 0; curPWM -= 5) {
+    PWM(curPWM);
+    this_thread::sleep_for(chrono::seconds(TIMEOUT));
+
+    int curRPM = RPM();
+
+    if (curRPM <= 0) {
+      minPWM = curPWM + 5;
+      break;
+    }
+  }
+
+  if (minPWM == 0) {
+    cout << "Fan never stopped. ";
+  }
+  cout << "Setting minimal PWM: " << minPWM << endl;
+
+  mMinPWM = minPWM;
+}
+
+void HwmonFan::FindStartPWM() {}
 
 json HwmonFan::toJson() const {
   json obj;
-  obj = {mPWMControl->toJson(), mRpmSensor->toJson(), mLabel};
+  obj = {mPWMControl->toJson(),
+         mRpmSensor->toJson(),
+         {"label", mLabel},
+         {"MinPWM", mMinPWM}};
   return obj;
 }