spi_slave: auto deselect chip

src/spi_slave.rs

@@ -49,7 +49,9 @@ where
 	fn transfer<'w>(&mut self, words: &'w mut[u8]) -> Result<&'w [u8], Self::Error> {
 		self.0.do_on_get_ref_mut_data(move |mut dev| {
 			dev.select_chip(self.1);
-			dev.spi.transfer(words).map_err(Error::SPI)
+			let result = dev.spi.transfer(words).map_err(Error::SPI);
+			dev.select_chip(0);
+			result
 		})	
 	}
 }