offer clear_idle_interrupt from serial::Rx in DMA Transfer

currently, if DMA is used for a `Serial` connection, it is not possible
to clear the idle interrupt without manually copying the implementation
of the `Rx::clear_idle_interrupt` method.
with this, a consumer can now properly call the method directly on the
`Transfer`.

this solves #550

Author: rursprung

CHANGELOG.md

@@ -54,6 +54,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
  - Added rtic-usart-shell example [#551]
  - Added rtic-usart-shell-ssd1306 example [#551]
  - Added rtic-usb-cdc-echo example [#553]
+ - Add possibility to clear a Serial `Rx` idle interrupt from a DMA `Transfer` [#556]
 
 
 [#481]: https://github.com/stm32-rs/stm32f4xx-hal/pull/481
@@ -79,6 +80,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 [#553]: https://github.com/stm32-rs/stm32f4xx-hal/pull/553
 [#554]: https://github.com/stm32-rs/stm32f4xx-hal/pull/554
 [#555]: https://github.com/stm32-rs/stm32f4xx-hal/pull/555
+[#556]: https://github.com/stm32-rs/stm32f4xx-hal/pull/556
 
 ## [v0.13.2] - 2022-05-16
 

src/dma/mod.rs

@@ -21,6 +21,7 @@ use crate::pac::RCC;
 use crate::{pac, rcc};
 
 pub mod traits;
+use crate::serial::RxISR;
 use traits::{
     sealed::{Bits, Sealed},
     Channel, DMASet, Direction, Instance, PeriAddress, SafePeripheralRead, Stream, StreamISR,
@@ -1014,6 +1015,20 @@ where
     }
 }
 
+impl<STREAM, const CHANNEL: u8, PERIPHERAL, BUF>
+    Transfer<STREAM, CHANNEL, PERIPHERAL, PeripheralToMemory, BUF>
+where
+    STREAM: Stream,
+    ChannelX<CHANNEL>: Channel,
+    PERIPHERAL: PeriAddress + DMASet<STREAM, CHANNEL, PeripheralToMemory> + RxISR,
+    BUF: ReadBuffer<Word = <PERIPHERAL as PeriAddress>::MemSize>,
+{
+    /// Clear idle line interrupt flag
+    pub fn clear_idle_interrupt(&self) {
+        self.peripheral.clear_idle_interrupt();
+    }
+}
+
 impl<STREAM, const CHANNEL: u8, PERIPHERAL, BUF>
     Transfer<STREAM, CHANNEL, PERIPHERAL, PeripheralToMemory, BUF>
 where