Serialport Support

- allow communication to elm327 device via a serialport
- allow creation of elm327 device without requiring unwrap()
- added some extra documentation
- expose reset() functionality of device
- serial_comm and ftdi_comm abstractions added

src/device/mod.rs

@@ -3,6 +3,18 @@
 mod elm327;
 pub use elm327::Elm327;
 
+mod serial_comm;
+
+#[cfg(feature = "ftdi_comm")]
+mod ftdi_comm;
+#[cfg(feature = "ftdi_comm")]
+pub use ftdi_comm::FTDIDevice;
+
+#[cfg(feature = "serialport_comm")]
+mod serialport_comm;
+#[cfg(feature = "serialport_comm")]
+pub use serialport_comm::SerialPort;
+
 type Result<T> = std::result::Result<T, Error>;
 
 /// A lower-level API for using an OBD-II device
@@ -51,9 +63,15 @@ pub trait Obd2Reader {
 #[derive(thiserror::Error, Debug)]
 pub enum Error {
     /// An error with the underlying [FTDI device](ftdi::Device)
+    #[cfg(feature = "ftdi_comm")]
     #[error("FTDI error: `{0:?}`")]
     Ftdi(ftdi::Error),
 
+    /// An error with the underlying [serialport device](serialport::SerialPort)
+    #[cfg(feature = "serialport_comm")]
+    #[error("Serialport error: `{0:?}`")]
+    Serialport(serialport::Error),
+
     /// An I/O error in a low-level [std::io] stream operation
     #[error("IO error: `{0:?}`")]
     IO(std::io::Error),
@@ -63,12 +81,20 @@ pub enum Error {
     Communication(String),
 }
 
+#[cfg(feature = "ftdi_comm")]
 impl From<ftdi::Error> for Error {
     fn from(e: ftdi::Error) -> Self {
         Error::Ftdi(e)
     }
 }
 
+#[cfg(feature = "serialport_comm")]
+impl From<serialport::Error> for Error {
+    fn from(e: serialport::Error) -> Self {
+        Error::Serialport(e)
+    }
+}
+
 impl From<std::io::Error> for Error {
     fn from(e: std::io::Error) -> Self {
         Error::IO(e)