Stub in the DMA bits that aren't yet there.

embassy-stm32/src/dma/mod.rs

@@ -1,9 +1,11 @@
 #![macro_use]
 
+#[cfg(dma)]
 #[cfg_attr(dma_v1, path = "v1.rs")]
 #[cfg_attr(dma_v2, path = "v2.rs")]
 mod _version;
 
+#[cfg(dma)]
 #[allow(unused)]
 pub use _version::*;
 

embassy-stm32/src/lib.rs

@@ -26,7 +26,7 @@ pub mod adc;
 pub mod clock;
 #[cfg(dac)]
 pub mod dac;
-#[cfg(dma)]
+#[cfg(any(dma, dmamux))]
 pub mod dma;
 #[cfg(all(eth, feature = "net"))]
 pub mod eth;

embassy-stm32/src/usart/v3.rs

@@ -21,7 +21,8 @@ impl<'d, T: Instance> Uart<'d, T> {
     ) -> Self {
         unborrow!(inner, rx, tx);
 
-        T::enable();
+        // Uncomment once we find all of the H7's UART clocks.
+        //T::enable();
         let pclk_freq = T::frequency();
 
         // TODO: better calculation, including error checking and OVER8 if possible.

examples/stm32l4/src/bin/usart.rs

@@ -58,7 +58,10 @@ fn main() -> ! {
         w.dbg_stop().set_bit()
     });
 
-    pp.RCC.ahb1enr.modify(|_, w| w.dma1en().set_bit());
+    pp.RCC.ahb1enr.modify(|_, w| {
+        w.dma1en().set_bit();
+        w
+    });
 
     pp.RCC.ahb2enr.modify(|_, w| {
         w.gpioaen().set_bit();
@@ -70,6 +73,11 @@ fn main() -> ! {
         w
     });
 
+    pp.RCC.apb1enr1.modify(|_, w| {
+        w.uart4en().set_bit();
+        w
+    });
+
     pp.RCC.apb2enr.modify(|_, w| {
         w.syscfgen().set_bit();
         w