init

Cargo.toml

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+[package]
+name = "relay_control"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+gpio-cdev = "0.6"
+clap = { version = "4", features = ["derive"] }

src/main.rs

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+use clap::{Parser, Subcommand};
+use gpio_cdev::{Chip, LineRequestFlags};
+use std::{thread, time::Duration};
+
+/// Banana Pi M5 relay controller (gpiochip0 line 68 = CON1-P11).
+#[derive(Parser, Debug)]
+#[command(author, version, about)]
+struct Cli {
+    #[command(subcommand)]
+    cmd: Command,
+}
+
+#[derive(Subcommand, Debug)]
+enum Command {
+    /// Turn relay ON (active-low → set line 0)
+    On,
+    /// Turn relay OFF (set line 1)
+    Off,
+    /// Pulse relay ON for N ms, then OFF
+    Pulse {
+        #[arg(long, default_value_t = 500)]
+        ms: u64,
+    },
+}
+
+fn main() -> anyhow::Result<()> {
+    let cli = Cli::parse();
+
+    // Open gpiochip0
+    let mut chip = Chip::new("/dev/gpiochip0")?;
+
+    // Request line 68 (CON1-P11) as output, default HIGH (relay OFF)
+    let handle = chip
+        .get_line(68)?
+        .request(LineRequestFlags::OUTPUT, 1, "relay_control")?;
+
+    match cli.cmd {
+        Command::On => {
+            println!("Relay ON");
+            handle.set_value(0)?;
+        }
+        Command::Off => {
+            println!("Relay OFF");
+            handle.set_value(1)?;
+        }
+        Command::Pulse { ms } => {
+            println!("Relay ON for {} ms", ms);
+            handle.set_value(0)?;
+            thread::sleep(Duration::from_millis(ms));
+            println!("Relay OFF");
+            handle.set_value(1)?;
+        }
+    }
+
+    Ok(())
+}
+