Take ownership of Spi in activate_ref

README.md

@@ -65,7 +65,7 @@ Usage of borrowed SPI-Bus and previously initialized `Device`:
         let mut buffer = [0u8; 1024];
         match device
             // scoped activation & usage of the SPI bus without move
-            .activate_ref(&mut FourWireRef::new(&mut spi, &mut cs))
+            .activate_ref(FourWireRef::new(&mut spi, &mut cs))
             .receive(socket, &mut buffer)
         {
             Ok(..) => todo!(),

src/bus/four_wire_ref.rs

@@ -6,8 +6,6 @@ use embedded_hal::digital::v2::OutputPin;
 
 use crate::bus::{Bus, FourWire, FourWireError};
 
-const WRITE_MODE_MASK: u8 = 0b00000_1_00;
-
 // TODO This name is not ideal, should be renamed to VDM
 /// This is just like [crate::bus::FourWire] but takes references instead of ownership
 /// for the SPI bus and the ChipSelect pin
@@ -45,7 +43,7 @@ impl<Spi: Transfer<u8> + Write<u8>, ChipSelect: OutputPin> Bus
 }
 
 #[derive(Debug)]
-pub struct SpiRef<'a, Spi: Transfer<u8> + Write<u8>>(&'a mut Spi);
+pub struct SpiRef<'a, Spi: Transfer<u8> + Write<u8>>(pub &'a mut Spi);
 
 impl<'a, Spi: Transfer<u8> + Write<u8>> Transfer<u8> for SpiRef<'a, Spi> {
     type Error = <Spi as Transfer<u8>>::Error;
@@ -66,7 +64,7 @@ impl<'a, Spi: Transfer<u8> + Write<u8>> Write<u8> for SpiRef<'a, Spi> {
 }
 
 #[derive(Debug)]
-pub struct OutputPinRef<'a, P: OutputPin>(&'a mut P);
+pub struct OutputPinRef<'a, P: OutputPin>(pub &'a mut P);
 
 impl<'a, P: OutputPin> OutputPin for OutputPinRef<'a, P> {
     type Error = P::Error;

src/bus/mod.rs

@@ -19,3 +19,19 @@ pub trait Bus {
 
     fn write_frame(&mut self, block: u8, address: u16, data: &[u8]) -> Result<(), Self::Error>;
 }
+
+pub struct BusRef<'a, B: Bus>(pub &'a mut B);
+
+impl<B: Bus> Bus for BusRef<'_, B> {
+    type Error = B::Error;
+
+    #[inline]
+    fn read_frame(&mut self, block: u8, address: u16, data: &mut [u8]) -> Result<(), Self::Error> {
+        self.0.read_frame(block, address, data)
+    }
+
+    #[inline]
+    fn write_frame(&mut self, block: u8, address: u16, data: &[u8]) -> Result<(), Self::Error> {
+        self.0.write_frame(block, address, data)
+    }
+}

src/device.rs

@@ -1,7 +1,7 @@
 use bit_field::BitArray;
 use embedded_hal::digital::v2::OutputPin;
 
-use crate::bus::{Bus, FourWire, ThreeWire};
+use crate::bus::{Bus, BusRef, FourWire, SpiRef, ThreeWire};
 use crate::host::Host;
 use crate::net::Ipv4Addr;
 use crate::socket::Socket;
@@ -88,9 +88,9 @@ impl<SpiBus: Bus, HostImpl: Host> Device<SpiBus, HostImpl> {
     }
 
     #[inline]
-    pub(crate) fn as_mut(&mut self) -> DeviceRefMut<'_, SpiBus, HostImpl> {
+    pub(crate) fn as_mut(&mut self) -> DeviceRefMut<'_, BusRef<'_, SpiBus>, HostImpl> {
         DeviceRefMut {
-            bus: &mut self.bus,
+            bus: BusRef(&mut self.bus),
             state: &mut self.state,
         }
     }
@@ -104,30 +104,16 @@ impl<SpiBus: Bus, HostImpl: Host> Device<SpiBus, HostImpl> {
     }
 }
 
-impl<'a, SpiBus: Bus, HostImpl: Host> From<&'a mut Device<SpiBus, HostImpl>>
-    for DeviceRefMut<'a, SpiBus, HostImpl>
-{
-    fn from(device: &'a mut Device<SpiBus, HostImpl>) -> Self {
-        DeviceRefMut {
-            bus: &mut device.bus,
-            state: &mut device.state,
-        }
-    }
-}
-
 pub struct InactiveDevice<HostImpl: Host>(DeviceState<HostImpl>);
 
 impl<HostImpl: Host> InactiveDevice<HostImpl> {
-    /// Activates the device by ownership
+    /// Activates the device by taking ownership
     pub fn activate<SpiBus: Bus>(self, bus: SpiBus) -> Device<SpiBus, HostImpl> {
         Device { bus, state: self.0 }
     }
 
-    /// Activates the device by borrowing
-    pub fn activate_ref<'a, SpiBus: Bus>(
-        &'a mut self,
-        bus: &'a mut SpiBus,
-    ) -> DeviceRefMut<'a, SpiBus, HostImpl> {
+    /// Activates the device by borrowing it
+    pub fn activate_ref<SpiBus: Bus>(&mut self, bus: SpiBus) -> DeviceRefMut<SpiBus, HostImpl> {
         DeviceRefMut {
             bus,
             state: &mut self.0,
@@ -136,7 +122,7 @@ impl<HostImpl: Host> InactiveDevice<HostImpl> {
 }
 
 pub struct DeviceRefMut<'a, SpiBus: Bus, HostImpl: Host> {
-    pub(crate) bus: &'a mut SpiBus,
+    pub(crate) bus: SpiBus,
     state: &'a mut DeviceState<HostImpl>,
 }
 

src/lib.rs

@@ -11,7 +11,7 @@ mod socket;
 pub mod udp;
 mod uninitialized_device;
 
-pub use device::{Device, InactiveDevice};
+pub use device::{Device, DeviceRefMut, InactiveDevice};
 pub use host::{Dhcp, HostConfig, Manual};
 pub use net::MacAddress;
 pub use uninitialized_device::UninitializedDevice;

src/udp.rs

@@ -245,9 +245,9 @@ where
     ) -> Result<(), Self::Error> {
         if let SocketAddr::V4(remote) = remote {
             // TODO dynamically select a random port
-            socket.open(&mut *self.bus, 49849 + u16::from(socket.socket.index))?; // chosen by fair dice roll.
-                                                                                  // guaranteed to be random.
-            socket.set_destination(self.bus, remote)?;
+            socket.open(&mut self.bus, 49849 + u16::from(socket.socket.index))?; // chosen by fair dice roll.
+                                                                                 // guaranteed to be random.
+            socket.set_destination(&mut self.bus, remote)?;
             Ok(())
         } else {
             Err(Self::Error::UnsupportedAddress)
@@ -255,7 +255,7 @@ where
     }
 
     fn send(&mut self, socket: &mut Self::UdpSocket, buffer: &[u8]) -> nb::Result<(), Self::Error> {
-        socket.send(self.bus, buffer)?;
+        socket.send(&mut self.bus, buffer)?;
         Ok(())
     }
 
@@ -264,11 +264,11 @@ where
         socket: &mut Self::UdpSocket,
         buffer: &mut [u8],
     ) -> nb::Result<(usize, SocketAddr), Self::Error> {
-        Ok(socket.receive(self.bus, buffer)?)
+        Ok(socket.receive(&mut self.bus, buffer)?)
     }
 
     fn close(&mut self, socket: Self::UdpSocket) -> Result<(), Self::Error> {
-        socket.close(self.bus)?;
+        socket.close(&mut self.bus)?;
         self.release_socket(socket.socket);
         Ok(())
     }
@@ -301,7 +301,7 @@ where
     HostImpl: Host,
 {
     fn bind(&mut self, socket: &mut Self::UdpSocket, local_port: u16) -> Result<(), Self::Error> {
-        socket.open(self.bus, local_port)?;
+        socket.open(&mut self.bus, local_port)?;
         Ok(())
     }
 
@@ -312,7 +312,7 @@ where
         buffer: &[u8],
     ) -> nb::Result<(), Self::Error> {
         if let SocketAddr::V4(remote) = remote {
-            socket.send_to(self.bus, remote, buffer)?;
+            socket.send_to(&mut self.bus, remote, buffer)?;
             Ok(())
         } else {
             Err(nb::Error::Other(Self::Error::UnsupportedAddress))