Added an example of GPIO task for Raspberry pi.

examples/rp-gpio/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "rp-gpio"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+copper = { path = "../../copper" }
+rppal = "0.18.0"

examples/rp-gpio/src/lib.rs

@@ -0,0 +1,44 @@
+use copper::config::NodeInstanceConfig;
+use copper::cutask::{CuMsg, CuSinkTask, CuTaskLifecycle};
+use copper::{CuError, CuResult};
+
+use rppal::gpio::{Gpio, OutputPin};
+
+/// Example of a GPIO output driver for the Raspberry Pi
+/// The config takes one config value: `pin` which is the pin you want to address
+/// Gpio uses BCM pin numbering. For example: BCM GPIO 23 is tied to physical pin 16.
+pub struct RPGpio {
+    pin: OutputPin,
+}
+
+impl CuTaskLifecycle for RPGpio {
+    fn new(config: Option<&NodeInstanceConfig>) -> CuResult<Self>
+    where
+        Self: Sized,
+    {
+        let config =
+            config.ok_or("RPGpio needs a config, None was passed as NodeInstanceConfig")?;
+
+        let pin_nb: u8 = (*config.get("pin").expect(
+            "RPGpio expects a pin config value pointing to output pin you want to address",
+        ))
+        .clone()
+        .into();
+
+        let pin = Gpio::new()
+            .map_err(|e| CuError::new_with_cause("Failed to initialize GPIO", e))?
+            .get(pin_nb)
+            .map_err(|e| CuError::new_with_cause("Could not get pin", e))?
+            .into_output();
+        Ok(Self { pin })
+    }
+}
+
+impl CuSinkTask for RPGpio {
+    type Input = u8;
+
+    fn process(&mut self, msg: &CuMsg<Self::Input>) -> CuResult<()> {
+        self.pin.write(msg.payload.into());
+        Ok(())
+    }
+}