Add ADC support to DMA API

This doesn't do anything in itself, as the ADC API is currently not
making use of this.

Author: hannobraun

src/adc.rs

@@ -193,6 +193,13 @@ where
 pub struct Ready;
 
 
+/// Used for DMA transfers
+///
+/// This is an internal implementation detail. It is only public because it
+/// leaks out of a public API in the form of a `where` clause.
+pub struct DmaToken(());
+
+
 macro_rules! int_adc {
     ($($Chan:ident: ($chan:expr, $en:ident)),+ $(,)*) => {
         $(

src/dma.rs

@@ -27,6 +27,7 @@ use core::{
 use as_slice::AsSlice;
 
 use crate::{
+    adc,
     i2c,
     pac::{
         self,
@@ -471,6 +472,10 @@ macro_rules! impl_target {
 
 // See STM32L0x2 Reference Manual, table 51 (page 267).
 impl_target!(
+    // ADC
+    adc::DmaToken, Channel1, 0;
+    adc::DmaToken, Channel2, 0;
+
     // USART1
     serial::Tx<USART1>, Channel2, 3;
     serial::Tx<USART1>, Channel4, 3;