refactor(gpio): remove support for open-drain outputs for now

The API of embassy-nrf does not seem consistent with the hardware and
the other Embassy crates.

src/riot-rs-embassy/src/arch/dummy/gpio.rs

@@ -87,7 +87,6 @@ pub mod output {
         gpio::{FromDriveStrength, FromSpeed, PinState},
     };
 
-    pub(crate) const OPEN_DRAIN_AVAILABLE: bool = false;
     pub(crate) const DRIVE_STRENGTH_AVAILABLE: bool = false;
     pub(crate) const SPEED_AVAILABLE: bool = false;
 
@@ -102,15 +101,6 @@ pub mod output {
         unimplemented!();
     }
 
-    pub(crate) fn new_open_drain(
-        pin: impl Peripheral<P: Pin> + 'static,
-        initial_state: PinState,
-        drive_strength: DriveStrength,
-        _speed: Speed, // Not supported by this architecture
-    ) -> OpenDrainOutput<'static> {
-        unimplemented!();
-    }
-
     #[derive(Copy, Clone, PartialEq, Eq)]
     pub enum DriveStrength {}
 
@@ -156,32 +146,4 @@ pub mod output {
             unimplemented!();
         }
     }
-
-    pub struct OpenDrainOutput<'d> {
-        _marker: core::marker::PhantomData<&'d ()>,
-    }
-
-    impl embedded_hal::digital::ErrorType for OpenDrainOutput<'_> {
-        type Error = core::convert::Infallible;
-    }
-
-    impl OutputPin for OpenDrainOutput<'_> {
-        fn set_low(&mut self) -> Result<(), Self::Error> {
-            unimplemented!();
-        }
-
-        fn set_high(&mut self) -> Result<(), Self::Error> {
-            unimplemented!();
-        }
-    }
-
-    impl StatefulOutputPin for OpenDrainOutput<'_> {
-        fn is_set_high(&mut self) -> Result<bool, Self::Error> {
-            unimplemented!();
-        }
-
-        fn is_set_low(&mut self) -> Result<bool, Self::Error> {
-            unimplemented!();
-        }
-    }
 }

src/riot-rs-embassy/src/arch/esp/gpio.rs

@@ -93,9 +93,8 @@ pub mod output {
         gpio::{FromDriveStrength, FromSpeed, PinState},
     };
 
-    pub(crate) use esp_hal::gpio::{AnyOutput as Output, AnyOutputOpenDrain as OpenDrainOutput};
+    pub(crate) use esp_hal::gpio::AnyOutput as Output;
 
-    pub(crate) const OPEN_DRAIN_AVAILABLE: bool = true;
     // FIXME: ESP32 *does* support setting the drive strength, but esp-hal seems to currently make
     // this impossible on `AnyOuput` (unlike on `Output`), because it internally uses an
     // `ErasedPin`.
@@ -118,22 +117,6 @@ pub mod output {
         output
     }
 
-    // FIXME
-    pub(crate) fn new_open_drain(
-        pin: impl Peripheral<P: Pin> + 'static,
-        initial_state: PinState,
-        drive_strength: DriveStrength,
-        _speed: Speed, // Not supported by this architecture
-    ) -> OpenDrainOutput<'static> {
-        todo!();
-        // let initial_state: bool = initial_state.into();
-        // let initial_state = Level::from(initial_state);
-        // let mut output = OpenDrainOutput::new(pin, initial_state);
-        // TODO
-        // output.set_drive_strength(drive_strength.into());
-        // output
-    }
-
     // We do not provide a `Default` impl as not all pins have the same reset value.
     #[derive(Copy, Clone, PartialEq, Eq)]
     pub enum DriveStrength {

src/riot-rs-embassy/src/arch/nrf/gpio.rs

@@ -52,11 +52,8 @@ pub mod output {
         gpio::{FromDriveStrength, FromSpeed, PinState},
     };
 
-    // We re-export `Output` twice, for consistency with other architectures that have a dedicated
-    // type for open-drain outputs.
-    pub(crate) use embassy_nrf::gpio::{Output, Output as OpenDrainOutput, Pin};
+    pub(crate) use embassy_nrf::gpio::{Output, Pin};
 
-    pub(crate) const OPEN_DRAIN_AVAILABLE: bool = true;
     pub(crate) const DRIVE_STRENGTH_AVAILABLE: bool = true;
     pub(crate) const SPEED_AVAILABLE: bool = false;
 
@@ -68,31 +65,13 @@ pub mod output {
     ) -> Output<'static> {
         let initial_state: bool = initial_state.into();
         let initial_state = Level::from(initial_state);
-        // TODO: this also depends on the open-drain configuration
         let output_drive = match drive_strength {
             DriveStrength::Standard => OutputDrive::Standard,
             DriveStrength::High => OutputDrive::HighDrive,
         };
         Output::new(pin, initial_state, output_drive)
     }
 
-    pub(crate) fn new_open_drain(
-        pin: impl Peripheral<P: Pin> + 'static,
-        initial_state: PinState,
-        drive_strength: DriveStrength,
-        _speed: Speed, // Not supported by this architecture
-    ) -> OpenDrainOutput<'static> {
-        // TODO: maybe factor this out with `new()`
-        let initial_state: bool = initial_state.into();
-        let initial_state = Level::from(initial_state);
-        // TODO: this also depends on the open-drain configuration
-        let output_drive = match drive_strength {
-            DriveStrength::Standard => OutputDrive::Standard0Disconnect1,
-            DriveStrength::High => OutputDrive::HighDrive0Disconnect1,
-        };
-        Output::new(pin, initial_state, output_drive)
-    }
-
     #[derive(Copy, Clone, PartialEq, Eq)]
     pub enum DriveStrength {
         Standard,

src/riot-rs-embassy/src/arch/rp2040/gpio.rs

@@ -49,9 +49,8 @@ pub mod output {
         gpio::{FromDriveStrength, FromSpeed, PinState},
     };
 
-    pub(crate) use embassy_rp::gpio::{Output, OutputOpenDrain as OpenDrainOutput, Pin};
+    pub(crate) use embassy_rp::gpio::{Output, Pin};
 
-    pub(crate) const OPEN_DRAIN_AVAILABLE: bool = true;
     pub(crate) const DRIVE_STRENGTH_AVAILABLE: bool = true;
     pub(crate) const SPEED_AVAILABLE: bool = true;
 
@@ -69,20 +68,6 @@ pub mod output {
         output
     }
 
-    pub(crate) fn new_open_drain(
-        pin: impl Peripheral<P: Pin> + 'static,
-        initial_state: PinState,
-        drive_strength: DriveStrength,
-        speed: Speed,
-    ) -> OpenDrainOutput<'static> {
-        let initial_state: bool = initial_state.into();
-        let initial_state = Level::from(initial_state);
-        let mut output = OpenDrainOutput::new(pin, initial_state);
-        output.set_drive_strength(drive_strength.into());
-        output.set_slew_rate(speed.into());
-        output
-    }
-
     // We provide our own type because the upstream type is not `Copy` and has no `Default` impl.
     #[derive(Copy, Clone, PartialEq, Eq)]
     pub enum DriveStrength {

src/riot-rs-embassy/src/gpio.rs

@@ -5,8 +5,8 @@ use crate::arch::{
     gpio::{
         input::{Input as ArchInput, Pin as ArchInputPin},
         output::{
-            DriveStrength as ArchDriveStrength, OpenDrainOutput as ArchOpenDrainOutput,
-            Output as ArchOutput, Pin as ArchOutputPin, Speed as ArchSpeed,
+            DriveStrength as ArchDriveStrength, Output as ArchOutput, Pin as ArchOutputPin,
+            Speed as ArchSpeed,
         },
     },
     peripheral::Peripheral,
@@ -211,7 +211,6 @@ pub struct Output {
 }
 
 impl Output {
-    // TODO: is PinState appropriate if we turn this into a open-drain-capable output?
     pub fn new(pin: impl Peripheral<P: ArchOutputPin> + 'static, initial_state: PinState) -> Self {
         Self::builder(pin, initial_state).build()
     }
@@ -244,28 +243,6 @@ impl Output {
     }
 }
 
-// FIXME: rename it to OutputOpenDrain for consistency with Embassy?
-pub struct OpenDrainOutput {
-    output: ArchOpenDrainOutput<'static>, // FIXME: is this ok to require a 'static pin?
-}
-
-impl OpenDrainOutput {
-    pub fn set_low(&mut self) {
-        // All architectures are infallible.
-        let _ = <Self as OutputPin>::set_low(self);
-    }
-
-    pub fn set_high(&mut self) {
-        // All architectures are infallible.
-        let _ = <Self as OutputPin>::set_high(self);
-    }
-
-    pub fn toggle(&mut self) {
-        // All architectures are infallible.
-        let _ = <Self as StatefulOutputPin>::toggle(self);
-    }
-}
-
 pub struct OutputBuilder<P: Peripheral<P: ArchOutputPin>> {
     pin: P,
     initial_state: PinState,
@@ -389,29 +366,9 @@ impl<P: Peripheral<P: ArchOutputPin> + 'static> OutputBuilder<P> {
 
         Output { output }
     }
-
-    pub fn build_open_drain(self) -> OpenDrainOutput {
-        // It is not clear whether any architectures does *not* support open-drain, but we still
-        // check it for forward compatibility.
-        const {
-            assert!(
-                arch::gpio::output::OPEN_DRAIN_AVAILABLE,
-                "This architecture does not support open-drain GPIO outputs."
-            );
-        }
-
-        // TODO: should we move this into `output::new()`s?
-        let drive_strength = <ArchDriveStrength as FromDriveStrength>::from(self.drive_strength);
-        // TODO: should we move this into `output::new()`s?
-        let speed = <ArchSpeed as FromSpeed>::from(self.speed);
-
-        let output =
-            arch::gpio::output::new_open_drain(self.pin, self.initial_state, drive_strength, speed);
-
-        OpenDrainOutput { output }
-    }
 }
 
+// We wrap this into a macro because it will be re-used for open-drain outputs
 macro_rules! impl_embedded_hal_output_traits {
     ($type:ident, $arch_type:ident) => {
         impl embedded_hal::digital::ErrorType for $type {
@@ -446,4 +403,3 @@ macro_rules! impl_embedded_hal_output_traits {
 }
 
 impl_embedded_hal_output_traits!(Output, ArchOutput);
-impl_embedded_hal_output_traits!(OpenDrainOutput, ArchOpenDrainOutput);