* Heltec tracker: new 'periph_power' shared pin (between Display & GPS)

src/helpers/RefCountedDigitalPin.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include <Arduino.h>
+
+class RefCountedDigitalPin {
+  uint8_t _pin;
+  int8_t _claims = 0;
+
+public:
+  RefCountedDigitalPin(uint8_t pin): _pin(pin) { }
+
+  void begin() {
+    pinMode(_pin, OUTPUT);
+    digitalWrite(_pin, LOW);  // initial state
+  }
+
+  void claim() {
+    _claims++;
+    if (_claims > 0) {
+      digitalWrite(_pin, HIGH);
+    }
+  }
+  void release() {
+    _claims--;
+    if (_claims == 0) {
+      digitalWrite(_pin, LOW);
+    }
+  }
+};