Basic comment cleanup in supporting SPI files (#94)

* Basic comment cleanup in supporting SPI files

* Added wording from feedback

src/System.Device.Gpio/System/Device/Spi/Drivers/UnixSpiDevice.Linux.cs

@@ -11,7 +11,7 @@ namespace System.Device.Spi.Drivers
         private const string Default_Device_Path = "/dev/spidev";
         private const uint SPI_IOC_MESSAGE_1 = 0x40206b00;
         private int _deviceFileDescriptor = -1;
-        private SpiConnectionSettings _settings;
+        private readonly SpiConnectionSettings _settings;
         private static readonly object s_InitializationLock = new object();
 
         public UnixSpiDevice(SpiConnectionSettings settings)

src/System.Device.Gpio/System/Device/Spi/SpiConnectionSettings.cs

@@ -5,40 +5,40 @@
 namespace System.Device.Spi
 {
     /// <summary>
-    /// Class that holds the connection settings of a device on a Spi bus.
+    /// The connection settings of a device on a SPI bus.
     /// </summary>
     public sealed class SpiConnectionSettings
     {
         private const SpiMode _defaultSpiMode = SpiMode.Mode0;
-        private const int _defaultDataBitLenght = 8; // 1 byte.
+        private const int _defaultDataBitLength = 8; // 1 byte
         private const int _defaultClockFrequency = 500_000; // 500 KHz
 
         private SpiConnectionSettings() { }
 
         /// <summary>
-        /// Default constructor. Takes the bus id and the chip select line for that bus.
+        /// Initializes new instance of SpiConnectionSettings.
         /// </summary>
-        /// <param name="busId">The bus id the device is connected to.</param>
-        /// <param name="chipSelectLine">The chip select line used on that bus id.</param>
+        /// <param name="busId">The bus ID the device is connected to.</param>
+        /// <param name="chipSelectLine">The chip select line used on the bus.</param>
         public SpiConnectionSettings(int busId, int chipSelectLine)
         {
             BusId = busId;
             ChipSelectLine = chipSelectLine;
             Mode = _defaultSpiMode;
-            DataBitLength = _defaultDataBitLenght;
+            DataBitLength = _defaultDataBitLength;
             ClockFrequency = _defaultClockFrequency;
         }
 
         /// <summary>
-        /// The Spi mode being used.
+        /// The SPI mode being used.
         /// </summary>
         public SpiMode Mode { get; set; }
         /// <summary>
-        /// The bus id the device is connected to.
+        /// The bus ID the device is connected to.
         /// </summary>
         public int BusId { get; set; }
         /// <summary>
-        /// The chip select line used on that bus id.
+        /// The chip select line used on the bus.
         /// </summary>
         public int ChipSelectLine { get; set; }
         /// <summary>

src/System.Device.Gpio/System/Device/Spi/SpiDevice.cs

@@ -12,11 +12,13 @@ namespace System.Device.Spi
         public abstract void WriteByte(byte data);
         public abstract void Write(Span<byte> data);
         public abstract void TransferFullDuplex(Span<byte> writeBuffer, Span<byte> readBuffer);
+
         public void Dispose()
         {
             Dispose(true);
             GC.SuppressFinalize(this);
         }
+
         public virtual void Dispose(bool disposing)
         {
             //Nothing to do in base class.

src/System.Device.Gpio/System/Device/Spi/SpiMode.cs

@@ -5,26 +5,26 @@
 namespace System.Device.Spi
 {
     /// <summary>
-    /// Enum with the different modes supported by SPI.
-    /// CPOL - Clock polarity: defines if each cycle consists of a pulse of 1, or 0.
-    /// CPHA - Clock phase: timing of the data bits relative to the clock pulses.
+    /// Defines how data is synchronized between devices on a SPI bus.
+    /// Clock Polarity (CPOL) determines if clock signal is low or high when in idle state.
+    /// Clock Phase (CPHA) determines when data is sampled relative to the clock signal.
     /// </summary>
     public enum SpiMode
     {
         /// <summary>
-        /// CPOL 0, CPHA 0
+        /// CPOL 0, CPHA 0. Polarity is idled low and data is sampled on rising edge of the clock signal.
         /// </summary>
         Mode0,
         /// <summary>
-        /// CPOL 0, CPHA 1
+        /// CPOL 0, CPHA 1. Polarity is idled low and data is sampled on falling edge of the clock signal.
         /// </summary>
         Mode1,
         /// <summary>
-        /// CPOL 1, CPHA 0
+        /// CPOL 1, CPHA 0. Polarity is idled high and data is sampled on falling edge of the clock signal.
         /// </summary>
         Mode2,
         /// <summary>
-        /// CPOL 1, CPHA 1
+        /// CPOL 1, CPHA 1. Polarity is idled high and data is sampled on rising edge of the clock signal.
         /// </summary>
         Mode3
     }