Add libgpiodv2 support

Documentation/raspi-libgpiodv2.md

@@ -0,0 +1,99 @@
+# Use libgpiodv2 on a Raspberry Pi
+
+If you want to control GPIOs using libgpiod version 2 the library must be installed.
+
+As of now (12/2023) only a few distros ship version 2 with their package manager, which requires manual installation.
+
+## Install libgpiod v2.x
+
+The installation should be the same on all Pi's, or other boards.
+
+1. Install build dependencies
+
+   ``````shell
+   sudo apt update && sudo apt install -y autogen autoconf autoconf-archive libtool libtool-bin pkg-config build-essential
+
+   ``````
+
+2. Download the tarball and unpack it: Go to [releases](https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/refs/) and copy the download URL of a libgpiod version
+
+   ``````shell
+   wget https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/snapshot/libgpiod-2.1.tar.gz
+   tar -xzf libgpiod-2.1.tar.gz
+   ``````
+
+   or any other version
+
+3. Compile libgpiod and install (see [BUILDING](https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/about/))
+
+   ``````shell
+   cd libgpiod-2.1/
+   ./autogen.sh
+   make
+   sudo make install
+   sudo ldconfig
+   ``````
+
+   This will install the library .so files to `/usr/lib/local`
+
+   If you want to also build command line utilities `gpioinfo, gpiodetect` etc., specify `./autogen.sh --enable-tools=yes`
+
+
+
+# GPIO blink example using libgpiodv2
+
+If not already done, install dotnet, see "Install dotnet" below.
+
+`dotnet iot` will search common library paths on Linux to find `libgpiod.so.3` so no step is required here.
+
+Simply use the `GpioController` like this:
+
+``````c#
+// side note: on the Raspberry Pi the GPIO chip line offsets are the same numbers as the usual BCM GPIO numbering, which is convenient
+const int inputPin = 14;
+const int outputPin = 15;
+
+// on the Pi3,4 you most likely want 0, on the Pi5 number 4, see 'gpioinfo' tool
+const int chipNumber = 0;
+// 'using' will dispose the controller when it falls out of scope, which will un-claim lines
+using var gpioController = new GpioController(chipNumber);
+
+gpioController.OpenPin(inputPin);
+gpioController.OpenPin(outputPin);
+
+for (int i = 0; i < 5; i++)
+{
+    controller.Write(outputPin, PinValue.High);
+    await Task.Delay(1000);
+    controller.Write(outputPin, PinValue.Low);
+    await Task.Delay(1000);
+}
+``````
+
+Or register a callback for edge events:
+
+``````c#
+...
+controller.RegisterCallbackForPinValueChangedEvent(inputPin, PinEventTypes.Falling | PinEventTypes.Rising, (sender, eventArgs) =>
+{
+    int pinNr = eventArgs.PinNumber;
+    PinEventTypes changeType = eventArgs.ChangeType;
+    Console.WriteLine($"Line '{pinNr}' changed to '{changeType}'");
+});
+...
+``````
+
+
+
+# Install dotnet
+
+Currently `dotnet iot` targets .NET 6 (might change in the future)
+
+``````shell
+curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --channel 6.0
+echo 'export DOTNET_ROOT=$HOME/.dotnet' >> ~/.bashrc
+echo 'export PATH=$PATH:$HOME/.dotnet' >> ~/.bashrc
+source ~/.bashrc
+``````
+
+See [docs](https://learn.microsoft.com/de-de/dotnet/iot/deployment)

src/System.Device.Gpio.Tests/LibGpiodDriverTests.cs

@@ -1,7 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Device.Gpio.Drivers;
+using System.Device.Gpio.System.Device.Gpio.Drivers.Libgpiod.V1;
 using System.Threading;
 using Xunit;
 using Xunit.Abstractions;
@@ -18,7 +18,7 @@ public LibGpiodDriverTests(ITestOutputHelper testOutputHelper)
     {
     }
 
-    protected override GpioDriver GetTestDriver() => new LibGpiodDriver();
+    protected override GpioDriver GetTestDriver() => new LibGpiodV1Driver();
 
     protected override PinNumberingScheme GetTestNumberingScheme() => PinNumberingScheme.Logical;
 

src/System.Device.Gpio.Tests/LibGpiodV2DriverTests.cs

@@ -0,0 +1,28 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Device.Gpio.System.Device.Gpio.Drivers.Libgpiod.V2;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace System.Device.Gpio.Tests;
+
+[Trait("feature", "gpio")]
+[Trait("feature", "gpio-libgpiod")]
+[Trait("SkipOnTestRun", "Windows_NT")]
+public class LibGpiodV2DriverTests : GpioControllerTestBase
+{
+    /// <summary>
+    /// Set to a low value to not delay tests too much, see constructor of <see cref="LibGpiodV2Driver"/>
+    /// </summary>
+    private static readonly TimeSpan s_eventReadTimeout = TimeSpan.FromMilliseconds(1);
+
+    public LibGpiodV2DriverTests(ITestOutputHelper testOutputHelper)
+        : base(testOutputHelper)
+    {
+    }
+
+    protected override GpioDriver GetTestDriver() => new LibGpiodV2Driver(0, waitForEventsTimeout: s_eventReadTimeout);
+
+    protected override PinNumberingScheme GetTestNumberingScheme() => PinNumberingScheme.Logical;
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/Interop.libgpiod.cs → src/System.Device.Gpio/Interop/Unix/libgpiod/V1/Interop.libgpiod.cs

@@ -7,6 +7,7 @@
 
 using System;
 using System.Device.Gpio;
+using System.Device.Gpio.Interop.Unix.libgpiod.V1;
 using System.Runtime.InteropServices;
 #if NET6_0_OR_GREATER
 using System.Runtime.Loader;
@@ -17,7 +18,7 @@
 
 internal partial class Interop
 {
-    internal static partial class Libgpiod
+    internal static partial class LibgpiodV1
     {
 #if NET6_0_OR_GREATER
         private const string LibgpiodLibrary = "libgpiod.so.2";
@@ -26,11 +27,11 @@ internal static partial class Libgpiod
 #endif
         internal static IntPtr InvalidHandleValue;
 
-        static Libgpiod()
+        static LibgpiodV1()
         {
             InvalidHandleValue = new IntPtr(-1);
 #if NET6_0_OR_GREATER
-            Assembly currentAssembly = typeof(Libgpiod).Assembly;
+            Assembly currentAssembly = typeof(LibgpiodV1).Assembly;
 
             AssemblyLoadContext.GetLoadContext(currentAssembly)!.ResolvingUnmanagedDll += (assembly, libgpiodName) =>
             {

src/System.Device.Gpio/Interop/Unix/SafeChipHandle.cs → src/System.Device.Gpio/Interop/Unix/libgpiod/V1/SafeChipHandle.cs

@@ -1,9 +1,13 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
 using System.Runtime.InteropServices;
+using LibgpiodV1 = Interop.LibgpiodV1;
 
-namespace System.Device.Gpio;
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V1;
 
 /// <summary>
 /// Pointer to a general-purpose I/O (GPIO) chip.
@@ -17,9 +21,9 @@ public SafeChipHandle()
 
     protected override bool ReleaseHandle()
     {
-        Interop.Libgpiod.gpiod_chip_close(handle);
+        LibgpiodV1.gpiod_chip_close(handle);
         return true;
     }
 
-    public override bool IsInvalid => handle == IntPtr.Zero || handle == Interop.Libgpiod.InvalidHandleValue;
+    public override bool IsInvalid => handle == IntPtr.Zero || handle == global::Interop.LibgpiodV1.InvalidHandleValue;
 }

src/System.Device.Gpio/Interop/Unix/SafeChipIteratorHandle.cs → src/System.Device.Gpio/Interop/Unix/libgpiod/V1/SafeChipIteratorHandle.cs

@@ -1,9 +1,13 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
 using System.Runtime.InteropServices;
+using LibgpiodV1 = Interop.LibgpiodV1;
 
-namespace System.Device.Gpio;
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V1;
 
 /// <summary>
 /// Pointer to an iterator of all GPIO chips available on the device.
@@ -17,9 +21,9 @@ public SafeChipIteratorHandle()
 
     protected override bool ReleaseHandle()
     {
-        Interop.Libgpiod.gpiod_chip_iter_free(handle);
+        LibgpiodV1.gpiod_chip_iter_free(handle);
         return true;
     }
 
-    public override bool IsInvalid => handle == IntPtr.Zero || handle == Interop.Libgpiod.InvalidHandleValue;
+    public override bool IsInvalid => handle == IntPtr.Zero || handle == LibgpiodV1.InvalidHandleValue;
 }

src/System.Device.Gpio/Interop/Unix/SafeLineHandle.cs → src/System.Device.Gpio/Interop/Unix/libgpiod/V1/SafeLineHandle.cs

@@ -1,9 +1,13 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
 using System.Runtime.InteropServices;
+using LibgpiodV1 = Interop.LibgpiodV1;
 
-namespace System.Device.Gpio;
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V1;
 
 /// <summary>
 /// Pointer to a pin.
@@ -20,17 +24,17 @@ public SafeLineHandle()
     protected override bool ReleaseHandle()
     {
         // Contrary to intuition, this does not invalidate the handle (see comment on declaration)
-        Interop.Libgpiod.gpiod_line_release(handle);
+        LibgpiodV1.gpiod_line_release(handle);
         return true;
     }
 
     /// <summary>
-    /// Release the lock on the line handle. <see cref="Interop.Libgpiod.gpiod_line_release"/>
+    /// Release the lock on the line handle. <see cref="LibgpiodV1.gpiod_line_release"/>
     /// </summary>
     public void ReleaseLock()
     {
         ReleaseHandle();
     }
 
-    public override bool IsInvalid => handle == IntPtr.Zero || handle == Interop.Libgpiod.InvalidHandleValue;
+    public override bool IsInvalid => handle == IntPtr.Zero || handle == LibgpiodV1.InvalidHandleValue;
 }

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodEdgeEventType.cs

@@ -0,0 +1,14 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__edge__event.html"/>
+internal enum GpiodEdgeEventType
+{
+    RisingEdge = 1,
+    FallingEdge
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineBias.cs

@@ -0,0 +1,17 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__defs.html"/>
+internal enum GpiodLineBias
+{
+    AsIs = 1,
+    Unknown,
+    Disabled,
+    PullUp,
+    PullDown
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineClock.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__defs.html"/>
+internal enum GpiodLineClock
+{
+    Monotonic = 1,
+    Realtime,
+    Hte
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineDirection.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__defs.html"/>
+internal enum GpiodLineDirection
+{
+    AsIs = 1,
+    Input,
+    Output
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineDrive.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__defs.html"/>
+internal enum GpiodLineDrive
+{
+    PushPull = 1,
+    OpenDrain,
+    OpenSource
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineEdge.cs

@@ -0,0 +1,16 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__defs.html"/>
+internal enum GpiodLineEdge
+{
+    None = 1,
+    Rising,
+    Falling,
+    Both
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineInfoEventType.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__watch.html"/>
+internal enum GpiodLineInfoEventType
+{
+    LineRequested = 1,
+    LineReleased,
+    LineConfigChanged
+}

src/System.Device.Gpio/Interop/Unix/libgpiod/V2/Binding/Enums/GpiodLineValue.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+// Disable these StyleCop rules for this file, as we are using native names here.
+#pragma warning disable SA1300 // Element should begin with upper-case letter
+
+namespace System.Device.Gpio.Interop.Unix.libgpiod.V2.Binding.Enums;
+
+/// <seealso href="https://libgpiod.readthedocs.io/en/latest/group__line__defs.html"/>
+internal enum GpiodLineValue
+{
+    Error = -1,
+    Inactive = 0,
+    Active = 1
+}