1 files changed, 142 insertions, 0 deletions
diff --git a/src/interface.rs b/src/interface.rs
new file mode 100644
index 0000000..2bf14f2
--- /dev/null
+++ b/src/interface.rs
@@ -0,0 +1,142 @@
+//! I2C/SPI interfaces
+
+#![deny(missing_docs)]
+
+extern crate embedded_hal as hal;
+use hal::blocking;
+use Error;
+
+/// I2C interface
+#[derive(Debug, Default)]
+pub struct I2cInterface<I2C> {
+    pub(crate) i2c: I2C,
+    pub(crate) address : u8,
+}
+
+/// SPI interface
+#[derive(Debug, Default)]
+pub struct SpiInterface<SPI, CS> {
+    pub(crate) spi: SPI,
+    pub(crate) cs: CS
+}
+
+/// Write data
+pub trait WriteData {
+    /// Error type
+    type Error;
+    /// Write to an u8 register
+    fn write_register(&mut self, register: u8, data: u8) -> Result<(), Error<Self::Error>>;
+    /// Write data. The first element corresponds to the starting address.
+    fn write_data(&mut self, payload: &mut [u8]) -> Result<(), Error<Self::Error>>;
+}
+
+impl<I2C, E> WriteData for I2cInterface<I2C>
+where
+    I2C: blocking::i2c::Write<Error = E>
+{
+    type Error = E;
+    fn write_register(&mut self, register: u8, data: u8) -> Result<(), Error<E>> {
+        let payload: [u8; 2] = [register, data];
+        self.i2c
+            .write(self.address, &payload)
+            .map_err(Error::Comm)
+    }
+
+    fn write_data(&mut self, payload: &mut [u8]) -> Result<(), Error<Self::Error>> {
+        self.i2c
+            .write(self.address, &payload)
+            .map_err(Error::Comm)
+    }
+}
+
+impl<SPI, CS, E> WriteData for SpiInterface<SPI, CS>
+where
+    SPI: blocking::spi::Write<u8, Error = E>,
+    CS:  hal::digital::OutputPin
+{
+    type Error = E;
+    fn write_register(&mut self, register: u8, data: u8) -> Result<(), Error<E>> {
+        self.cs.set_low();
+
+        let payload: [u8; 2] = [register + 0x80, data];
+        let result = self.spi
+                         .write(&payload)
+                         .map_err(Error::Comm);
+
+        self.cs.set_high();
+        result
+    }
+
+    fn write_data(&mut self, payload: &mut [u8]) -> Result<(), Error<Self::Error>> {
+        self.cs.set_low();
+        payload[0] += 0x80;
+        let result = self.spi
+                         .write(&payload)
+                         .map_err(Error::Comm);
+
+        self.cs.set_high();
+        result
+    }
+}
+
+
+/// Read data
+pub trait ReadData {
+    /// Error type
+    type Error;
+    /// Read an u8 register
+    fn read_register(&mut self, register: u8) -> Result<u8, Error<Self::Error>>;
+    /// Read some data. The first element corresponds to the starting address.
+    fn read_data(&mut self, payload: &mut [u8]) -> Result<(), Error<Self::Error>>;
+}
+
+impl<I2C, E> ReadData for I2cInterface<I2C>
+where
+    I2C: blocking::i2c::WriteRead<Error = E>
+{
+    type Error = E;
+    fn read_register(&mut self, register: u8) -> Result<u8, Error<E>> {
+        let mut data = [0];
+        self.i2c
+            .write_read(self.address, &[register], &mut data)
+            .map_err(Error::Comm)
+            .and(Ok(data[0]))
+    }
+
+    fn read_data(&mut self, payload: &mut [u8]) -> Result<(), Error<Self::Error>> {
+        let len = payload.len();
+        self.i2c
+            .write_read(self.address, &[payload[0]], &mut payload[1..=(len-1)])
+            .map_err(Error::Comm)
+    }
+}
+
+impl<SPI, CS, E> ReadData for SpiInterface<SPI, CS>
+where
+    SPI: blocking::spi::Transfer<u8, Error = E>,
+    CS:  hal::digital::OutputPin
+{
+    type Error = E;
+    fn read_register(&mut self, register: u8) -> Result<u8, Error<E>> {
+        self.cs.set_low();
+        let mut data = [register, 0];
+        let result = self.spi
+                         .transfer(&mut data)
+                         .map_err(Error::Comm);
+        self.cs.set_high();
+        match result {
+            Ok(result) => Ok(result[1]),
+            Err(e) => Err(e)
+        }
+    }
+
+    fn read_data(&mut self, mut payload: &mut [u8]) -> Result<(), Error<Self::Error>> {
+        self.cs.set_low();
+        let result = self.spi
+                         .transfer(&mut payload)
+                         .map_err(Error::Comm);
+        self.cs.set_high();
+        result?;
+        Ok(())
+    }
+}