Add futures::digital::AsyncInputPin trait

Author: lachlansneff

src/futures/digital.rs

@@ -0,0 +1,18 @@
+//! Asynchronous digital I/O
+
+use core::future::Future;
+
+/// Asynchronously wait for a pin to become high or low.
+pub trait AsyncInputPin {
+    /// The future returned by the `until_high` function.
+    type UntilHighFuture<'a>: Future<Output=()> + 'a;
+
+    /// The future returned by the `until_low` function.
+    type UntilLowFuture<'a>: Future<Output=()> + 'a;
+
+    /// Returns a future that resolves when this pin becomes high.
+    fn until_high<'a>(&self) -> Self::UntilHighFuture<'a>;
+
+    /// Returns a future that resolves when this pin becomes high.
+    fn until_low<'a>(&self) -> Self::UntilLowFuture<'a>;
+}

src/futures/mod.rs

@@ -6,3 +6,4 @@ pub mod i2c;
 pub mod serial;
 pub mod spi;
 pub mod delay;
+pub mod digital;