Add I2C support to the DMA API

This can't be used yet, as the I2C API itself doesn't support DMA yet.

Author: hannobraun

src/dma.rs

@@ -27,9 +27,13 @@ use core::{
 use as_slice::AsSlice;
 
 use crate::{
+    i2c,
     pac::{
         self,
         dma1::ccr1,
+        I2C1,
+        I2C2,
+        I2C3,
         USART1,
         USART2,
     },
@@ -476,16 +480,35 @@ macro_rules! impl_target {
     }
 }
 
+// See STM32L0x2 Reference Manual, table 51 (page 267).
 impl_target!(
+    // USART1
     serial::Tx<USART1>, Channel2, 3;
     serial::Tx<USART1>, Channel4, 3;
     serial::Rx<USART1>, Channel3, 3;
     serial::Rx<USART1>, Channel5, 3;
 
+    // USART2
     serial::Tx<USART2>, Channel4, 4;
     serial::Tx<USART2>, Channel7, 4;
     serial::Rx<USART2>, Channel5, 4;
     serial::Rx<USART2>, Channel6, 4;
+
+    // I2C1
+    i2c::Tx<I2C1>, Channel2, 6;
+    i2c::Rx<I2C1>, Channel3, 6;
+    i2c::Tx<I2C1>, Channel6, 6;
+    i2c::Rx<I2C1>, Channel7, 6;
+
+    // I2C2
+    i2c::Tx<I2C2>, Channel4, 7;
+    i2c::Rx<I2C2>, Channel5, 7;
+
+    // I2C3
+    i2c::Tx<I2C3>, Channel2, 14;
+    i2c::Rx<I2C3>, Channel3, 14;
+    i2c::Tx<I2C3>, Channel4, 14;
+    i2c::Rx<I2C3>, Channel5, 14;
 );
 
 // See STM32L0x2 Reference Manual, table 51 (page 267).

src/i2c.rs

@@ -1,6 +1,9 @@
 //! I2C
 
-use core::ops::Deref;
+use core::{
+    marker::PhantomData,
+    ops::Deref,
+};
 
 use crate::hal::blocking::i2c::{Read, Write, WriteRead};
 
@@ -382,3 +385,16 @@ i2c!(
         (PC0<Output<OpenDrain>>, AltMode::AF7),
     ],
 );
+
+
+/// Token used for DMA transfers
+///
+/// This is an implementation detail. The user doesn't have to deal with this
+/// directly.
+pub struct Tx<I>(PhantomData<I>);
+
+/// Token used for DMA transfers
+///
+/// This is an implementation detail. The user doesn't have to deal with this
+/// directly.
+pub struct Rx<I>(PhantomData<I>);