Implement FullDuplex for nrf spim

embassy-nrf-examples/src/bin/spim.rs

@@ -6,6 +6,7 @@
 
 #[path = "../example_common.rs"]
 mod example_common;
+use embassy_traits::spi::FullDuplex;
 use example_common::*;
 
 use cortex_m_rt::entry;
@@ -49,7 +50,7 @@ async fn run() {
     ncs.set_low().unwrap();
     cortex_m::asm::delay(5);
     let tx = [0xFF];
-    unwrap!(spim.as_mut().send_receive(&tx, &mut []).await);
+    unwrap!(spim.as_mut().read_write(&mut [], &tx).await);
     cortex_m::asm::delay(10);
     ncs.set_high().unwrap();
 
@@ -62,7 +63,7 @@ async fn run() {
     ncs.set_low().unwrap();
     cortex_m::asm::delay(5000);
     let tx = [0b000_11101, 0];
-    unwrap!(spim.as_mut().send_receive(&tx, &mut rx).await);
+    unwrap!(spim.as_mut().read_write(&mut rx, &tx).await);
     cortex_m::asm::delay(5000);
     ncs.set_high().unwrap();
     info!("estat: {=[?]}", rx);
@@ -72,7 +73,7 @@ async fn run() {
     ncs.set_low().unwrap();
     cortex_m::asm::delay(5);
     let tx = [0b100_11111, 0b11];
-    unwrap!(spim.as_mut().send_receive(&tx, &mut rx).await);
+    unwrap!(spim.as_mut().read_write(&mut rx, &tx).await);
     cortex_m::asm::delay(10);
     ncs.set_high().unwrap();
 
@@ -81,7 +82,7 @@ async fn run() {
     ncs.set_low().unwrap();
     cortex_m::asm::delay(5);
     let tx = [0b000_10010, 0];
-    unwrap!(spim.as_mut().send_receive(&tx, &mut rx).await);
+    unwrap!(spim.as_mut().read_write(&mut rx, &tx).await);
     cortex_m::asm::delay(10);
     ncs.set_high().unwrap();
 

embassy-nrf/src/spim.rs

@@ -2,9 +2,11 @@ use core::future::Future;
 use core::pin::Pin;
 use core::sync::atomic::{compiler_fence, Ordering};
 use core::task::Poll;
+use embassy::traits;
 use embassy::util::WakerRegistration;
 use embassy_extras::peripheral::{PeripheralMutex, PeripheralState};
 use futures::future::poll_fn;
+use traits::spi::FullDuplex;
 
 use crate::interrupt::{self, Interrupt};
 use crate::{pac, slice_in_ram_or};
@@ -123,15 +125,33 @@ impl<T: Instance> Spim<T> {
         let (state, irq) = self.inner().free();
         (state.spim, irq)
     }
+}
 
-    pub fn send_receive<'a>(
+impl<T: Instance> FullDuplex<u8> for Spim<T> {
+    type Error = Error;
+
+    #[rustfmt::skip]
+    type WriteFuture<'a> where Self: 'a = impl Future<Output = Result<(), Self::Error>> + 'a;
+    #[rustfmt::skip]
+    type ReadFuture<'a> where Self: 'a = impl Future<Output = Result<(), Self::Error>> + 'a;
+    #[rustfmt::skip]
+    type WriteReadFuture<'a> where Self: 'a = impl Future<Output = Result<(), Self::Error>> + 'a;
+
+    fn read<'a>(self: Pin<&'a mut Self>, data: &'a mut [u8]) -> Self::ReadFuture<'a> {
+        async move { todo!() }
+    }
+    fn write<'a>(self: Pin<&'a mut Self>, data: &'a [u8]) -> Self::WriteFuture<'a> {
+        async move { todo!() }
+    }
+
+    fn read_write<'a>(
         mut self: Pin<&'a mut Self>,
-        tx: &'a [u8],
         rx: &'a mut [u8],
-    ) -> impl Future<Output = Result<(), Error>> + 'a {
+        tx: &'a [u8],
+    ) -> Self::WriteReadFuture<'a> {
         async move {
-            slice_in_ram_or(tx, Error::DMABufferNotInDataMemory)?;
             slice_in_ram_or(rx, Error::DMABufferNotInDataMemory)?;
+            slice_in_ram_or(tx, Error::DMABufferNotInDataMemory)?;
 
             self.as_mut().inner().with(|s, _irq| {
                 // Conservative compiler fence to prevent optimizations that do not

embassy-traits/src/spi.rs

@@ -1,6 +1,7 @@
 //! Async SPI API
 
 use core::future::Future;
+use core::pin::Pin;
 
 /// Full duplex (master mode)
 ///
@@ -22,15 +23,21 @@ pub trait FullDuplex<Word> {
     /// An enumeration of SPI errors
     type Error;
 
-    type WriteFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a;
-    type ReadFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a;
-    type WriteReadFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a;
+    type WriteFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a
+    where
+        Self: 'a;
+    type ReadFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a
+    where
+        Self: 'a;
+    type WriteReadFuture<'a>: Future<Output = Result<(), Self::Error>> + 'a
+    where
+        Self: 'a;
 
-    fn read<'a>(&'a mut self, data: &'a mut [Word]) -> Self::ReadFuture<'_>;
-    fn write<'a>(&'a mut self, data: &'a [Word]) -> Self::WriteFuture<'_>;
+    fn read<'a>(self: Pin<&'a mut Self>, data: &'a mut [Word]) -> Self::ReadFuture<'a>;
+    fn write<'a>(self: Pin<&'a mut Self>, data: &'a [Word]) -> Self::WriteFuture<'a>;
     fn read_write<'a>(
-        &mut self,
+        self: Pin<&'a mut Self>,
         read: &'a mut [Word],
         write: &'a [Word],
-    ) -> Self::WriteReadFuture<'_>;
+    ) -> Self::WriteReadFuture<'a>;
 }