Minor cleanup

Source/Meadow.Foundation.Peripherals/Sensors.Distance.Vl53l0x/Driver/Vl53l0x.cs

@@ -15,35 +15,22 @@ public partial class Vl53l0x : ByteCommsSensorBase<Length>, IRangeFinder, II2cPe
         /// <summary>
         /// Is the hardware shutdown / off
         /// </summary>
-        public bool IsShutdown
-        {
-            get
-            {
-                if (shutdownPort != null)
-                {
-                    return !shutdownPort.State;
-                }
-                else
-                {
-                    return false;
-                }
-            }
-        }
+        public bool IsShutdown => shutdownPort?.State ?? false;
 
         /// <summary>
         /// The distance to the measured object
         /// </summary>
-        public Length? Distance { get; protected set; } = new Length(0);
+        public Length? Distance { get; protected set; }
 
         /// <summary>
         /// Minimum valid distance
         /// </summary>
-        public Length MinimumDistance => new Length(30, Length.UnitType.Millimeters);
+        public static Length MinimumDistance = new(30, Length.UnitType.Millimeters);
 
         /// <summary>
-        /// Maximum valid distance (CurrentDistance returns -1 if above)
+        /// Maximum valid distance
         /// </summary>
-        public Length MaximumDistance => new Length(2000, Length.UnitType.Millimeters);
+        public static Length MaximumDistance = new(2, Length.UnitType.Meters);
 
         /// <summary>
         /// The default I2C address for the peripheral
@@ -242,23 +229,19 @@ public void MeasureDistance()
         /// <summary>
         /// Returns the current distance/range
         /// </summary>
-        /// <returns>The distance in the specified Units. Default mm. Returns -1 if the shutdown pin is used and is off</returns>
+        /// <returns>The current distance, returns 0 if the shutdown pin is used and is off</returns>
         protected override async Task<Length> ReadSensor()
         {
-            //Resolver.Log.Info("ReadSensor");
-
             if (IsShutdown)
             {
-                return new Length(-1f, Length.UnitType.Millimeters);
+                return new Length(0, Length.UnitType.Millimeters);
             }
 
-            // get the distance
             Distance = new Length(await GetRawRangeData(), Length.UnitType.Millimeters);
 
-            // throw away invalid distances if out of range
             if (Distance > MaximumDistance)
             {
-                Distance = new Length(-1, Length.UnitType.Millimeters);
+                Distance = MaximumDistance;
             }
 
             return Distance.Value;
@@ -271,7 +254,9 @@ protected override async Task<Length> ReadSensor()
         public void SetAddress(byte newAddress)
         {
             if (IsShutdown)
+            {
                 return;
+            }
 
             byte address = (byte)(newAddress & 0x7F);
             BusComms.WriteRegister((byte)Register.I2CSlaveDeviceAddress, address);
@@ -280,7 +265,7 @@ public void SetAddress(byte newAddress)
         /// <summary>
         /// Set the Shutdown state of the device
         /// </summary>
-        /// <param name="state">true = off/shutdown. false = on</param>
+        /// <param name="state">returns true if off/shutdown, false if on</param>
         public async Task ShutDown(bool state)
         {
             if (shutdownPort == null)
@@ -294,16 +279,14 @@ public async Task ShutDown(bool state)
             if (state == false)
             {
                 await Initialize();
-                // TODO: is this still needed? the previous line wasn't awaited before.
                 await Task.Delay(2).ConfigureAwait(false);
             }
         }
 
         /// <summary>
-        /// Get the spad info
+        /// Get the SPAD info
         /// </summary>
         /// <returns></returns>
-        /// <exception cref="Exception"></exception>
         protected Tuple<int, bool> GetSpadInfo()
         {
             BusComms.WriteRegister(0x80, 0x01);
@@ -388,6 +371,9 @@ int Read16(byte address)
             return (ReadBuffer.Span[0] << 8) | ReadBuffer.Span[1];
         }
 
+        /// <summary>
+        /// Returns the raw range data from the sensor in millimeters
+        /// </summary>
         async Task<int> GetRawRangeData()
         {
             BusComms.WriteRegister(0x80, 0x01);