add qei trait and implementation

embassy-traits/src/lib.rs

@@ -9,5 +9,6 @@
 pub mod delay;
 pub mod flash;
 pub mod gpio;
+pub mod qei;
 pub mod i2c;
 pub mod uart;

embassy-traits/src/qei.rs

@@ -0,0 +1,14 @@
+use core::future::Future;
+use core::pin::Pin;
+use embedded_hal::Direction;
+
+// Wait for a specified number of rotations either up or down
+pub trait WaitForRotate {
+    type RotateFuture<'a>: Future<Output = Direction> + 'a;
+
+    fn wait_for_rotate<'a>(
+        self: Pin<&'a mut Self>,
+        count_down: u16,
+        count_up: u16,
+    ) -> Self::RotateFuture<'a>;
+}