add softwire example

lib/examples/softwire.rs

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: 2024 Kent Gibson <[email protected]>
+//
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Basic piece of wire example mirroring an input to an output.
+
+use anyhow::Context;
+use gpiocdev::line::{EdgeDetection, EdgeKind, Value};
+use gpiocdev::Request;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let input = Request::builder()
+        .on_chip("/dev/gpiochip0")
+        .with_consumer("softwire")
+        .with_line(22)
+        .with_edge_detection(EdgeDetection::BothEdges)
+        .request()
+        .context("Failed to request input")?;
+
+    // copy value to output
+    let value = input.value(22)?;
+    let output = Request::builder()
+        .on_chip("/dev/gpiochip0")
+        .with_consumer("softwire")
+        .with_line(23)
+        .as_output(value)
+        .request()
+        .context("Failed to request output")?;
+
+    // track value
+    for event in input.edge_events() {
+        let value = match event?.kind {
+            EdgeKind::Rising => Value::Active,
+            EdgeKind::Falling => Value::Inactive,
+        };
+        output.set_lone_value(value)?;
+    }
+    Ok(())
+}