Add SpiDmaBus::split for moving between manual & automatic DMA buffers (#2824)

* Allow swapping dma buffers

* Deconstruct makes more sense

* Format

* Changelog

* Race-conditioned

* Change SpiDmaBus::deconstruct name to SpiDmaBus::split

* Add flush & bracket references

* Fix mutability

* Fix name of generic param

---------

Co-authored-by: ferris <ferris@devdroplets.com>
Co-authored-by: Dániel Buga <bugadani@gmail.com>

esp-hal/CHANGELOG.md

@@ -31,6 +31,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Peripheral singletons now implement `Debug` and `defmt::Format` (#2682, #2834)
 - `BurstConfig`, a device-specific configuration for configuring DMA transfers in burst mode (#2543)
 - `{DmaRxBuf, DmaTxBuf, DmaRxTxBuf}::set_burst_config` (#2543)
+- Added `SpiDmaBus::split` for moving between manual & automatic DMA buffers (#2824)
 - ESP32-S2: DMA support for AES (#2699)
 - Added `transfer_in_place_async` and embedded-hal-async implementation to `Spi` (#2691)
 - `InterruptHandler` now implements `Hash` and `defmt::Format` (#2830)

esp-hal/src/spi/master.rs

@@ -1653,6 +1653,12 @@ mod dma {
                 tx_buf,
             }
         }
+
+        /// Splits [SpiDmaBus] back into [SpiDma], [DmaRxBuf] and [DmaTxBuf].
+        pub fn split(mut self) -> (SpiDma<'d, Dm, T>, DmaRxBuf, DmaTxBuf) {
+            self.wait_for_idle();
+            (self.spi_dma, self.rx_buf, self.tx_buf)
+        }
     }
 
     impl<T> InterruptConfigurable for SpiDmaBus<'_, Blocking, T>