Implement Error for error types

src/lib.rs

@@ -13,6 +13,7 @@ use embedded_hal::{
     digital::{InputPin, OutputPin},
     spi::{Operation, SpiDevice},
 };
+use thiserror::Error;
 
 const EPD_WIDTH: usize = 240;
 const EPD_HEIGHT: usize = 320;
@@ -27,25 +28,31 @@ pub struct EPaperDisplay<BusyPin, ResetPin, DcPin, SpiDevice, Delay> {
     delay: Delay,
 }
 
+#[derive(Debug, Error)]
 /// An error that may occur during display initialisation.
 pub enum InitError<ResetError, DcError, SpiError> {
     /// This variant is for any error with setting the level of the reset pin.
     ///
     /// This variant may be uninhabited if the `ResetPin` type parameter for [EPaperDisplay] is one that
     /// doesn't produce errors.
+    #[error("While initialising the display, an error occurred when toggling the reset pin: {0}")]
     ResetError(ResetError),
     /// This variant is for errors when attempting to communicate with the display controller after reset.
+    #[error("While initialising the display, a communication error occurred: {0}")]
     WriteError(WriteError<DcError, SpiError>),
 }
 
+#[derive(Debug, Error)]
 /// An error when trying to communicate with the display controller.
 pub enum WriteError<DcError, SpiError> {
     /// This variant is for any error with setting the level of the DC (Data/Command) pin.
     ///
     /// This variant may be uninhabited if the `DcPin` type parameter for [EPaperDisplay] is one that
     /// doesn't produce errors.
+    #[error("Failed to set the data/command line: {0}")]
     DcError(DcError),
     /// This variant is for errors produced by the SPI driver.
+    #[error("Failed to perform SPI operations: {0}")]
     SpiError(SpiError),
 }