Began skeleton of new UninitializedW5500 struct and Bus trait/impls

src/bus/four_wire.rs

@@ -0,0 +1,39 @@
+use embedded_hal::digital::v2::OutputPin;
+use embedded_hal::spi::FullDuplex;
+
+use crate::bus::Bus;
+
+pub struct FourWire<ChipSelect: OutputPin> {
+    cs: ChipSelect
+}
+
+impl<ChipSelect: OutputPin>
+    FourWire<ChipSelect>
+{
+    pub fn new(cs: ChipSelect) -> Self {
+        Self { cs }
+    }
+    pub fn release(self) -> ChipSelect {
+        self.cs
+    }
+}
+
+impl<Spi: FullDuplex<u8>, ChipSelect: OutputPin> Bus<Spi>
+    for FourWire<ChipSelect>
+{
+    type Error = FourWireError<Spi::Error, ChipSelect::Error>;
+    fn transfer_frame<'a, 'b>(
+        spi: &'b mut Spi,
+        address_phase: [u8; 2],
+        control_phase: u8,
+        data_phase: &'a mut [u8],
+    ) -> Result<&'a mut [u8], nb::Error<Self::Error>> {
+        // TODO implement transfer
+        Ok(data_phase)
+    }
+}
+
+pub enum FourWireError<SpiError, ChipSelectError> {
+    SpiError(SpiError),
+    ChipSelectError(ChipSelectError),
+}

src/bus/mod.rs

@@ -0,0 +1,18 @@
+use nb::Result;
+use embedded_hal::spi::FullDuplex;
+
+mod four_wire;
+mod three_wire;
+
+pub use self::four_wire::FourWire;
+pub use self::three_wire::ThreeWire;
+
+pub trait Bus<Spi: FullDuplex<u8>> {
+    type Error;
+    fn transfer_frame<'a, 'b>(
+        spi: &'b mut Spi,
+        address_phase: [u8; 2],
+        control_phase: u8,
+        data_phase: &'a mut [u8],
+    ) -> Result<&'a mut [u8], Self::Error>;
+}

src/bus/three_wire.rs

@@ -0,0 +1,24 @@
+use embedded_hal::spi::FullDuplex;
+
+use crate::bus::Bus;
+
+pub struct ThreeWire {}
+
+impl ThreeWire {
+    pub fn new() -> Self {
+        Self { }
+    }
+}
+
+impl<Spi: FullDuplex<u8>> Bus<Spi> for ThreeWire {
+    type Error = Spi::Error;
+    fn transfer_frame<'a, 'b>(
+        spi: &'b mut Spi,
+        address_phase: [u8; 2],
+        control_phase: u8,
+        data_phase: &'a mut [u8],
+    ) -> Result<&'a mut [u8], nb::Error<Self::Error>> {
+        // TODO implement transfer
+        Ok(data_phase)
+    }
+}

src/uninitialized_w5500.rs

@@ -0,0 +1,34 @@
+use embedded_hal::spi::FullDuplex;
+use embedded_hal::digital::v2::OutputPin;
+use bus::{Bus, FourWire, ThreeWire};
+use w5500::W5500;
+
+pub struct UninitializedW5500<Spi: FullDuplex<u8>, SpiBus: Bus<Spi>> {
+    bus: SpiBus,
+    spi: Spi,
+}
+
+impl<Spi: FullDuplex<u8>, SpiBus: Bus<Spi>> UninitializedW5500<Spi, SpiBus> {
+    pub fn initialize() -> W5500 {
+        // TODO actually initialize chip
+        W5500 {}
+    }
+}
+
+impl<Spi: FullDuplex<u8>, ChipSelect: OutputPin> UninitializedW5500<Spi, FourWire<ChipSelect>> {
+    pub fn new(spi: Spi, cs: ChipSelect) -> Self {
+        Self { spi, bus: FourWire::new(cs) }
+    }
+    pub fn deactivate(self) -> (Spi, ChipSelect) {
+        (self.spi, self.bus.release())
+    }
+}
+
+impl<Spi: FullDuplex<u8>> UninitializedW5500<Spi, ThreeWire> {
+    pub fn new(spi: Spi) -> Self {
+        Self { spi, bus: ThreeWire::new() }
+    }
+    pub fn deactivate(self) -> Spi {
+        self.spi
+    }
+}

src/w5500.rs

@@ -0,0 +1 @@
+pub struct W5500 {}