spi/blocking: add default impls for write_iter and exec.

Author: Dirbaio

src/spi/blocking.rs

@@ -35,7 +35,13 @@ pub trait Write<W = u8>: Spi {
     /// Writes `words` to the slave, ignoring all the incoming words
     fn write_iter<WI>(&mut self, words: WI) -> Result<(), Self::Error>
     where
-        WI: IntoIterator<Item = W>;
+        WI: IntoIterator<Item = W>,
+    {
+        for word in words {
+            self.write(&[word])?;
+        }
+        Ok(())
+    }
 }
 
 impl<T: Write<W>, W> Write<W> for &mut T {
@@ -84,7 +90,17 @@ pub trait ReadWrite<W = u8>: Read<W> + Write<W> {
     fn transfer_inplace(&mut self, words: &mut [W]) -> Result<(), Self::Error>;
 
     /// Execute multiple actions as part of a single SPI transaction
-    fn exec<'a>(&mut self, operations: &mut [Operation<'a, W>]) -> Result<(), Self::Error>;
+    fn exec<'a>(&mut self, operations: &mut [Operation<'a, W>]) -> Result<(), Self::Error> {
+        for op in operations {
+            match op {
+                Operation::Read(words) => self.read(words)?,
+                Operation::Write(words) => self.write(words)?,
+                Operation::Transfer(read, write) => self.transfer(read, write)?,
+                Operation::TransferInplace(words) => self.transfer_inplace(words)?,
+            }
+        }
+        Ok(())
+    }
 }
 
 impl<T: ReadWrite<W>, W> ReadWrite<W> for &mut T {