Adding Api Feedback to PWM classes (#48)

src/System.Device.Gpio/System/Device/Pwm/IPwmDriver.cs

-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace System.Device.Pwm
-{
-    public interface IPwmDriver : IDisposable
-    {
-        void OpenChannel(int pwmChannel);
-        void CloseChannel(int pwmChannel);
-        void Start(int pwmChannel, double frequency, double dutyCycle);
-        void Stop(int pwmChannel);
-    }
-}

src/System.Device.Gpio/System/Device/Pwm/PwmController.cs

@@ -6,14 +6,12 @@ namespace System.Device.Pwm
 {
     public sealed class PwmController : IDisposable
     {
-        private PwmController() { }
-
-        public static PwmController GetController()
+        public PwmController()
         {
             throw new NotImplementedException();
         }
 
-        public static PwmController GetController(IPwmDriver driver)
+        public PwmController(PwmDriver driver)
         {
             throw new NotImplementedException();
         }
@@ -33,23 +31,24 @@ namespace System.Device.Pwm
             throw new NotImplementedException();
         }
 
-        public void Start(int pwmChannel, double frequency, double dutyCycle)
+        public void StartWriting(int pwmChannel, double frequency, double dutyCycle)
         {
             throw new NotImplementedException();
         }
 
-        public void Stop(int pwmChannel)
+        public void StopWriting(int pwmChannel)
         {
             throw new NotImplementedException();
         }
 
-        public static bool IsPwmEnabled()
+        public void Dispose()
         {
-            throw new NotImplementedException();
+
         }
 
-        ~PwmController() { }
+        private void Dispose(bool disposing)
+        {
 
-        public void Dispose() { }
+        }
     }
 }

src/System.Device.Gpio/System/Device/Pwm/PwmDriver.cs

+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.Device.Pwm
+{
+    public abstract class PwmDriver : IDisposable
+    {
+        protected internal abstract void OpenChannel(int pwmChannel);
+        protected internal abstract void CloseChannel(int pwmChannel);
+        protected internal abstract void StartWriting(int pwmChannel, double frequency, double dutyCycle);
+        protected internal abstract void StopWriting(int pwmChannel);
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+        protected virtual void Dispose(bool disposing)
+        {
+            // Nothing to do in the base class
+        }
+    }
+}

src/System.Device.Gpio/System/Device/Pwm/UnixPwmDriver.cs

@@ -4,29 +4,24 @@
 
 namespace System.Device.Pwm
 {
-    internal class UnixPwmDriver : IPwmDriver
+    internal class UnixPwmDriver : PwmDriver
     {
-        public void CloseChannel(int pwmChannel)
+        protected internal override void CloseChannel(int pwmChannel)
         {
             throw new NotImplementedException();
         }
 
-        public void Dispose()
+        protected internal override void OpenChannel(int pwmChannel)
         {
             throw new NotImplementedException();
         }
 
-        public void OpenChannel(int pwmChannel)
+        protected internal override void StartWriting(int pwmChannel, double frequency, double dutyCycle)
         {
             throw new NotImplementedException();
         }
 
-        public void Start(int pwmChannel, double frequency, double dutyCycle)
-        {
-            throw new NotImplementedException();
-        }
-
-        public void Stop(int pwmChannel)
+        protected internal override void StopWriting(int pwmChannel)
         {
             throw new NotImplementedException();
         }