Initial support for the x3

lib/hal/HalGPIO.h

@@ -23,6 +23,14 @@ class HalGPIO {
   InputManager inputMgr;
 #endif
 
+ public:
+  enum class DeviceType : uint8_t { X4, X3 };
+
+ private:
+  DeviceType _deviceType = DeviceType::X4;
+  int _detectAdcValue = 0;
+  int _batteryPin = BAT_GPIO0;
+
  public:
   HalGPIO() = default;
 
@@ -47,6 +55,11 @@ class HalGPIO {
   // Check if USB is connected
   bool isUsbConnected() const;
 
+  // Device detection helpers
+  DeviceType getDeviceType() const { return _deviceType; }
+  int getDetectAdcValue() const { return _detectAdcValue; }
+  int getBatteryPin() const { return _batteryPin; }
+
   enum class WakeupReason { PowerButton, AfterFlash, AfterUSBPower, Other };
 
   WakeupReason getWakeupReason() const;