Implement Wait for CdevPin with tokio runtime.

Cargo.toml

@@ -14,8 +14,8 @@ edition = "2018"
 
 [features]
 gpio_sysfs = ["sysfs_gpio"]
-gpio_cdev = ["gpio-cdev"]
-async-tokio = ["gpio-cdev/async-tokio", "dep:embedded-hal-async", "tokio/time"]
+gpio_cdev = ["dep:gpiocdev"]
+async-tokio = ["dep:embedded-hal-async", "tokio/time", "tokio/rt", "gpiocdev?/async_tokio"]
 i2c = ["i2cdev"]
 spi = ["spidev"]
 
@@ -25,7 +25,7 @@ default = [ "gpio_cdev", "gpio_sysfs", "i2c", "spi" ]
 embedded-hal = "1"
 embedded-hal-nb = "1"
 embedded-hal-async = { version = "1", optional = true }
-gpio-cdev = { version = "0.6.0", optional = true }
+gpiocdev = { version = "0.6.1", optional = true }
 sysfs_gpio = { version = "0.6.1", optional = true }
 i2cdev = { version = "0.6.0", optional = true }
 nb = "1"
@@ -36,8 +36,17 @@ tokio = { version = "1", default-features = false, optional = true }
 
 [dev-dependencies]
 openpty = "0.2.0"
+tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
 
 [dependencies.cast]
 # we don't need the `Error` implementation
 default-features = false
 version = "0.3"
+
+[[example]]
+name = "gpio-wait"
+required-features = ["async-tokio"]
+
+
+[patch.crates-io]
+gpiocdev = { git = "https://github.com/warthog618/gpiocdev-rs" }

examples/gpio-wait.rs

@@ -0,0 +1,39 @@
+use std::error::Error;
+use std::time::Duration;
+
+use embedded_hal::digital::{InputPin, OutputPin, PinState};
+use embedded_hal_async::digital::Wait;
+use linux_embedded_hal::CdevPin;
+use tokio::time::{sleep, timeout};
+
+// This example assumes that input/output pins are shorted.
+const CHIP: &str = "/dev/gpiochip0";
+const INPUT_LINE: u32 = 4;
+const OUTPUT_LINE: u32 = 17;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn Error>> {
+    let mut input_pin = CdevPin::new_input(CHIP, INPUT_LINE)?;
+    let mut output_pin = CdevPin::new_output(CHIP, OUTPUT_LINE, PinState::Low)?;
+
+    timeout(Duration::from_secs(10), async move {
+        let set_output = tokio::spawn(async move {
+            sleep(Duration::from_secs(5)).await;
+            println!("Setting output high.");
+            output_pin.set_high()
+        });
+
+        println!("Waiting for input to go high.");
+        input_pin.wait_for_high().await?;
+
+        assert!(input_pin.is_high()?);
+        println!("Input is now high.");
+
+        set_output.await??;
+
+        Ok::<_, Box<dyn Error>>(())
+    })
+    .await??;
+
+    Ok(())
+}