Use the embedded-hal::digital::v2::OutputPin traits (#8)

* Forward communication errors

* Use fallible OutputPin traits

Author: eldruin

Cargo.toml

@@ -16,7 +16,7 @@ branch = "master"
 repository = "jamwaffles/sh1106"
 
 [dependencies]
-embedded-hal = "0.2.2"
+embedded-hal = "0.2.3"
 
 [dependencies.embedded-graphics]
 optional = true

src/builder.rs

@@ -41,7 +41,7 @@
 //! ```
 
 use hal;
-use hal::digital::OutputPin;
+use hal::digital::v2::OutputPin;
 
 use crate::displayrotation::DisplayRotation;
 use crate::displaysize::DisplaySize;
@@ -77,9 +77,9 @@ impl Builder {
     }
 }
 
-impl<CS> Builder<CS>
+impl<CS, PinE> Builder<CS>
 where
-    CS: OutputPin,
+    CS: OutputPin<Error = PinE>,
 {
     /// Set the size of the display. Supported sizes are defined by [DisplaySize].
     pub fn with_size(self, display_size: DisplaySize) -> Self {
@@ -116,9 +116,9 @@ where
     }
 
     /// Finish the builder and use I2C to communicate with the display
-    pub fn connect_i2c<I2C>(self, i2c: I2C) -> DisplayMode<RawMode<I2cInterface<I2C>>>
+    pub fn connect_i2c<I2C, CommE>(self, i2c: I2C) -> DisplayMode<RawMode<I2cInterface<I2C>>>
     where
-        I2C: hal::blocking::i2c::Write,
+        I2C: hal::blocking::i2c::Write<Error = CommE>,
     {
         let properties = DisplayProperties::new(
             I2cInterface::new(i2c, self.i2c_addr),
@@ -129,14 +129,16 @@ where
     }
 
     /// Finish the builder and use SPI to communicate with the display
-    pub fn connect_spi<SPI, DC>(
+    pub fn connect_spi<SPI, DC, CommE>(
         self,
         spi: SPI,
         dc: DC,
     ) -> DisplayMode<RawMode<SpiInterface<SPI, DC, CS>>>
     where
-        SPI: hal::blocking::spi::Transfer<u8> + hal::blocking::spi::Write<u8>,
-        DC: OutputPin,
+        SPI: hal::blocking::spi::Transfer<u8, Error = CommE>
+            + hal::blocking::spi::Write<u8, Error = CommE>,
+        DC: OutputPin<Error = PinE>,
+        CS: OutputPin<Error = PinE>,
     {
         let properties = DisplayProperties::new(
             SpiInterface::new(spi, dc, self.spi_cs),
@@ -152,6 +154,11 @@ where
 pub struct NoOutputPin;
 
 impl OutputPin for NoOutputPin {
-    fn set_low(&mut self) {}
-    fn set_high(&mut self) {}
+    type Error = ();
+    fn set_low(&mut self) -> Result<(), ()> {
+        Ok(())
+    }
+    fn set_high(&mut self) -> Result<(), ()> {
+        Ok(())
+    }
 }

src/command.rs

@@ -51,7 +51,7 @@ pub enum Command {
 
 impl Command {
     /// Send command to sh1106
-    pub fn send<DI>(self, iface: &mut DI) -> Result<(), ()>
+    pub fn send<DI>(self, iface: &mut DI) -> Result<(), DI::Error>
     where
         DI: DisplayInterface,
     {
@@ -83,9 +83,7 @@ impl Command {
         };
 
         // Send command over the interface
-        iface.send_commands(&data[0..len])?;
-
-        Ok(())
+        iface.send_commands(&data[0..len])
     }
 }
 

src/interface/i2c.rs

@@ -4,6 +4,7 @@ use hal;
 
 use super::DisplayInterface;
 use crate::command::Page;
+use crate::Error;
 
 // TODO: Add to prelude
 /// sh1106 I2C communication interface
@@ -22,23 +23,27 @@ where
     }
 }
 
-impl<I2C> DisplayInterface for I2cInterface<I2C>
+impl<I2C, CommE> DisplayInterface for I2cInterface<I2C>
 where
-    I2C: hal::blocking::i2c::Write,
+    I2C: hal::blocking::i2c::Write<Error = CommE>,
 {
-    fn send_commands(&mut self, cmds: &[u8]) -> Result<(), ()> {
+    type Error = Error<CommE, ()>;
+
+    fn init(&mut self) -> Result<(), Self::Error> {
+        Ok(())
+    }
+
+    fn send_commands(&mut self, cmds: &[u8]) -> Result<(), Self::Error> {
         // Copy over given commands to new aray to prefix with command identifier
         let mut writebuf: [u8; 8] = [0; 8];
         writebuf[1..=cmds.len()].copy_from_slice(&cmds);
 
         self.i2c
             .write(self.addr, &writebuf[..=cmds.len()])
-            .map_err(|_| ())?;
-
-        Ok(())
+            .map_err(Error::Comm)
     }
 
-    fn send_data(&mut self, buf: &[u8]) -> Result<(), ()> {
+    fn send_data(&mut self, buf: &[u8]) -> Result<(), Self::Error> {
         // Display is always 128px wide
         const CHUNKLEN: usize = 128;
 
@@ -70,9 +75,9 @@ where
                         0x10, // Upper column address (always zero, base is 10h)
                     ],
                 )
-                .map_err(|_| ())?;
+                .map_err(Error::Comm)?;
 
-            self.i2c.write(self.addr, &writebuf).map_err(|_| ())?;
+            self.i2c.write(self.addr, &writebuf).map_err(Error::Comm)?;
 
             page += 1;
         }

src/interface/mod.rs

@@ -52,10 +52,15 @@ pub mod spi;
 
 /// A method of communicating with sh1106
 pub trait DisplayInterface {
+    /// Interface error type
+    type Error;
+
+    /// Initialize device.
+    fn init(&mut self) -> Result<(), Self::Error>;
     /// Send a batch of up to 8 commands to display.
-    fn send_commands(&mut self, cmd: &[u8]) -> Result<(), ()>;
+    fn send_commands(&mut self, cmd: &[u8]) -> Result<(), Self::Error>;
     /// Send data to display.
-    fn send_data(&mut self, buf: &[u8]) -> Result<(), ()>;
+    fn send_data(&mut self, buf: &[u8]) -> Result<(), Self::Error>;
 }
 
 pub use self::i2c::I2cInterface;

src/interface/spi.rs

@@ -1,9 +1,10 @@
 //! sh1106 SPI interface
 
 use hal;
-use hal::digital::OutputPin;
+use hal::digital::v2::OutputPin;
 
 use super::DisplayInterface;
+use crate::Error;
 
 /// SPI display interface.
 ///
@@ -14,48 +15,48 @@ pub struct SpiInterface<SPI, DC, CS> {
     cs: CS,
 }
 
-impl<SPI, DC, CS> SpiInterface<SPI, DC, CS>
+impl<SPI, DC, CS, CommE, PinE> SpiInterface<SPI, DC, CS>
 where
-    SPI: hal::blocking::spi::Write<u8>,
-    DC: OutputPin,
-    CS: OutputPin,
+    SPI: hal::blocking::spi::Write<u8, Error = CommE>,
+    DC: OutputPin<Error = PinE>,
+    CS: OutputPin<Error = PinE>,
 {
     /// Create new SPI interface for communciation with sh1106
-    pub fn new(spi: SPI, dc: DC, mut cs: CS) -> Self {
-        cs.set_high();
-
+    pub fn new(spi: SPI, dc: DC, cs: CS) -> Self {
         Self { spi, dc, cs }
     }
 }
 
-impl<SPI, DC, CS> DisplayInterface for SpiInterface<SPI, DC, CS>
+impl<SPI, DC, CS, CommE, PinE> DisplayInterface for SpiInterface<SPI, DC, CS>
 where
-    SPI: hal::blocking::spi::Write<u8>,
-    DC: OutputPin,
-    CS: OutputPin,
+    SPI: hal::blocking::spi::Write<u8, Error = CommE>,
+    DC: OutputPin<Error = PinE>,
+    CS: OutputPin<Error = PinE>,
 {
-    fn send_commands(&mut self, cmds: &[u8]) -> Result<(), ()> {
-        self.cs.set_low();
-        self.dc.set_low();
+    type Error = Error<CommE, PinE>;
+
+    fn init(&mut self) -> Result<(), Self::Error> {
+        self.cs.set_high().map_err(Error::Pin)
+    }
 
-        self.spi.write(&cmds).map_err(|_| ())?;
+    fn send_commands(&mut self, cmds: &[u8]) -> Result<(), Self::Error> {
+        self.cs.set_low().map_err(Error::Pin)?;
+        self.dc.set_low().map_err(Error::Pin)?;
 
-        self.dc.set_high();
-        self.cs.set_high();
+        self.spi.write(&cmds).map_err(Error::Comm)?;
 
-        Ok(())
+        self.dc.set_high().map_err(Error::Pin)?;
+        self.cs.set_high().map_err(Error::Pin)
     }
 
-    fn send_data(&mut self, buf: &[u8]) -> Result<(), ()> {
-        self.cs.set_low();
+    fn send_data(&mut self, buf: &[u8]) -> Result<(), Self::Error> {
+        self.cs.set_low().map_err(Error::Pin)?;
 
         // 1 = data, 0 = command
-        self.dc.set_high();
-
-        self.spi.write(&buf).map_err(|_| ())?;
+        self.dc.set_high().map_err(Error::Pin)?;
 
-        self.cs.set_high();
+        self.spi.write(&buf).map_err(Error::Comm)?;
 
-        Ok(())
+        self.cs.set_high().map_err(Error::Pin)
     }
 }

src/lib.rs

@@ -96,6 +96,15 @@
 #![deny(unused_import_braces)]
 #![deny(unused_qualifications)]
 
+/// Errors in this crate
+#[derive(Debug)]
+pub enum Error<CommE, PinE> {
+    /// Communication error
+    Comm(CommE),
+    /// Pin setting error
+    Pin(PinE),
+}
+
 extern crate embedded_hal as hal;
 
 pub mod builder;

src/mode/graphics.rs

@@ -16,13 +16,14 @@
 //! ```
 
 use hal::blocking::delay::DelayMs;
-use hal::digital::OutputPin;
+use hal::digital::v2::OutputPin;
 
 use crate::displayrotation::DisplayRotation;
 use crate::displaysize::DisplaySize;
 use crate::interface::DisplayInterface;
 use crate::mode::displaymode::DisplayModeTrait;
 use crate::properties::DisplayProperties;
+use crate::Error;
 
 const BUFFER_SIZE: usize = 132 * 64 / 8;
 
@@ -65,20 +66,24 @@ where
 
     /// Reset display
     // TODO: Move to a more appropriate place
-    pub fn reset<RST, DELAY>(&mut self, rst: &mut RST, delay: &mut DELAY)
+    pub fn reset<RST, DELAY, PinE>(
+        &mut self,
+        rst: &mut RST,
+        delay: &mut DELAY,
+    ) -> Result<(), Error<(), PinE>>
     where
-        RST: OutputPin,
+        RST: OutputPin<Error = PinE>,
         DELAY: DelayMs<u8>,
     {
-        rst.set_high();
+        rst.set_high().map_err(Error::Pin)?;
         delay.delay_ms(1);
-        rst.set_low();
+        rst.set_low().map_err(Error::Pin)?;
         delay.delay_ms(10);
-        rst.set_high();
+        rst.set_high().map_err(Error::Pin)
     }
 
     /// Write out data to display
-    pub fn flush(&mut self) -> Result<(), ()> {
+    pub fn flush(&mut self) -> Result<(), DI::Error> {
         let display_size = self.properties.get_size();
 
         // Ensure the display buffer is at the origin of the display before we send the full frame
@@ -147,9 +152,8 @@ where
 
     /// Display is set up in column mode, i.e. a byte walks down a column of 8 pixels from
     /// column 0 on the left, to column _n_ on the right
-    pub fn init(&mut self) -> Result<(), ()> {
-        self.properties.init_column_mode()?;
-        Ok(())
+    pub fn init(&mut self) -> Result<(), DI::Error> {
+        self.properties.init_column_mode()
     }
 
     /// Get display dimensions, taking into account the current rotation of the display
@@ -158,7 +162,7 @@ where
     }
 
     /// Set the display rotation
-    pub fn set_rotation(&mut self, rot: DisplayRotation) -> Result<(), ()> {
+    pub fn set_rotation(&mut self, rot: DisplayRotation) -> Result<(), DI::Error> {
         self.properties.set_rotation(rot)
     }
 }