Move Supreme OLED address to variant config

Keep SH1106Display generic by relying on DISPLAY_ADDRESS while the T-Beam Supreme variant declares its 0x3D OLED address.

src/helpers/ui/SH1106Display.cpp

@@ -11,17 +11,10 @@ bool SH1106Display::i2c_probe(TwoWire &wire, uint8_t addr)
 
 bool SH1106Display::begin()
 {
-  // Address selection: on some board revisions (notably the LilyGo T-Beam
-  // Supreme V3) the OLED lives at 0x3D because 0x3C is occupied by a
-  // magnetometer (QMC6310N). 0x3D is only ever used by the OLED, so prefer it
-  // when present, otherwise fall back to the standard 0x3C (DISPLAY_ADDRESS).
-  uint8_t addr = 0;
-  if (i2c_probe(Wire, 0x3D)) {
-    addr = 0x3D;
-  } else if (i2c_probe(Wire, DISPLAY_ADDRESS)) {
-    addr = DISPLAY_ADDRESS;
-  }
-  return addr && display.begin(addr, true);
+  // Wire must already be initialised by board.begin() before this is called.
+  // Boards with non-standard SH1106 addresses should define DISPLAY_ADDRESS
+  // in their variant/platformio configuration.
+  return i2c_probe(Wire, DISPLAY_ADDRESS) && display.begin(DISPLAY_ADDRESS, true);
 }
 
 void SH1106Display::turnOn()

variants/lilygo_tbeam_supreme_SX1262/platformio.ini

@@ -18,6 +18,7 @@ build_flags =
   -D RADIO_CLASS=CustomSX1262
   -D WRAPPER_CLASS=CustomSX1262Wrapper
   -D DISPLAY_CLASS=SH1106Display
+  -D DISPLAY_ADDRESS=0x3D
   -D LORA_TX_POWER=22
   -D P_LORA_TX_LED=6
   -D PIN_BOARD_SDA=17