Merge #1099

1099: rp: implement input for OutputOpenDrain r=Dirbaio a=Dirbaio

Needed for onewire and similar protocols.

Co-authored-by: Dario Nieuwenhuis <dirbaio@dirbaio.net>

embassy-rp/src/gpio.rs

@@ -411,6 +411,16 @@ impl<'d, T: Pin> OutputOpenDrain<'d, T> {
     pub fn toggle(&mut self) {
         self.pin.toggle_set_as_output()
     }
+
+    #[inline]
+    pub fn is_high(&self) -> bool {
+        self.pin.is_high()
+    }
+
+    #[inline]
+    pub fn is_low(&self) -> bool {
+        self.pin.is_low()
+    }
 }
 
 /// GPIO flexible pin.
@@ -791,6 +801,18 @@ mod eh02 {
         }
     }
 
+    impl<'d, T: Pin> embedded_hal_02::digital::v2::InputPin for OutputOpenDrain<'d, T> {
+        type Error = Infallible;
+
+        fn is_high(&self) -> Result<bool, Self::Error> {
+            Ok(self.is_high())
+        }
+
+        fn is_low(&self) -> Result<bool, Self::Error> {
+            Ok(self.is_low())
+        }
+    }
+
     impl<'d, T: Pin> embedded_hal_02::digital::v2::OutputPin for OutputOpenDrain<'d, T> {
         type Error = Infallible;
 
@@ -946,6 +968,16 @@ mod eh1 {
         }
     }
 
+    impl<'d, T: Pin> embedded_hal_1::digital::InputPin for OutputOpenDrain<'d, T> {
+        fn is_high(&self) -> Result<bool, Self::Error> {
+            Ok(self.is_high())
+        }
+
+        fn is_low(&self) -> Result<bool, Self::Error> {
+            Ok(self.is_low())
+        }
+    }
+
     impl<'d, T: Pin> embedded_hal_1::digital::ErrorType for Flex<'d, T> {
         type Error = Infallible;
     }

tests/rp/src/bin/gpio.rs

@@ -78,6 +78,7 @@ async fn main(_spawner: Spawner) {
         a.set_as_input();
 
         // When an OutputOpenDrain is high, it doesn't drive the pin.
+        b.set_high();
         a.set_pull(Pull::Up);
         delay();
         assert!(a.is_high());
@@ -85,9 +86,8 @@ async fn main(_spawner: Spawner) {
         delay();
         assert!(a.is_low());
 
-        b.set_low();
-
         // When an OutputOpenDrain is low, it drives the pin low.
+        b.set_low();
         a.set_pull(Pull::Up);
         delay();
         assert!(a.is_low());
@@ -95,14 +95,36 @@ async fn main(_spawner: Spawner) {
         delay();
         assert!(a.is_low());
 
+        // Check high again
         b.set_high();
-
         a.set_pull(Pull::Up);
         delay();
         assert!(a.is_high());
         a.set_pull(Pull::Down);
         delay();
         assert!(a.is_low());
+
+        // When an OutputOpenDrain is high, it reads the input value in the pin.
+        b.set_high();
+        a.set_as_input();
+        a.set_pull(Pull::Up);
+        delay();
+        assert!(b.is_high());
+        a.set_as_output();
+        a.set_low();
+        delay();
+        assert!(b.is_low());
+
+        // When an OutputOpenDrain is low, it always reads low.
+        b.set_low();
+        a.set_as_input();
+        a.set_pull(Pull::Up);
+        delay();
+        assert!(b.is_low());
+        a.set_as_output();
+        a.set_low();
+        delay();
+        assert!(b.is_low());
     }
 
     // FLEX