examples/fpga_config.rs

@@ -79,7 +79,7 @@ fn main() -> ! {
 	// Pre-load the configuration bytes
 	let config_data = include_bytes!("../build/top.bin");
 
-	flash_ice40_fpga(fpga_cfg_spi, fpga_ss, fpga_creset, fpga_cdone, delay, config_data).unwrap();
+	flash_ice40_fpga(fpga_cfg_spi, fpga_ss, fpga_creset, fpga_cdone, delay, config_data)?;
 
 	loop {
 		nop();

src/cpld.rs

@@ -23,7 +23,12 @@ pub struct CPLD<SPI, CS0, CS1, CS2, GPIO> {
     pub(crate) data: cell::RefCell<CPLDData<SPI, CS0, CS1, CS2, GPIO>>,
 }
 
-impl<SPI, CS0, CS1, CS2, GPIO, E> CPLDData<SPI, CS0, CS1, CS2, GPIO>
+pub trait SelectChip {
+    type Error;
+    fn select_chip(&mut self, chip: u8) -> Result<(), Self::Error>;
+}
+
+impl<SPI, CS0, CS1, CS2, GPIO, E> SelectChip for CPLDData<SPI, CS0, CS1, CS2, GPIO>
 where
     SPI: Transfer<u8, Error = E>,
     CS0: OutputPin,
@@ -31,7 +36,8 @@ where
     CS2: OutputPin,
     GPIO: OutputPin,
 {
-    pub(crate) fn select_chip(&mut self, chip: u8) -> Result<(), Error<E>> {
+    type Error = Error<E>;
+    fn select_chip(&mut self, chip: u8) -> Result<(), Self::Error> {
         match chip & (1 << 0) {
             0 => self.chip_select.0.set_low(),
             _ => self.chip_select.0.set_high(),
@@ -46,13 +52,49 @@ where
         }.map_err(|_| Error::CSError)?;
         Ok(())
     }
+}
 
-    pub(crate) fn issue_io_update(&mut self) -> Result<(), Error<E>> {
+pub trait IssueIOUpdate {
+    type Error;
+    fn issue_io_update(&mut self) -> Result<(), Self::Error>;
+}
+
+impl<SPI, CS0, CS1, CS2, GPIO, E> IssueIOUpdate for CPLDData<SPI, CS0, CS1, CS2, GPIO>
+where
+    SPI: Transfer<u8>,
+    CS0: OutputPin,
+    CS1: OutputPin,
+    CS2: OutputPin,
+    GPIO: OutputPin<Error = E>,
+{
+    type Error = Error<E>;
+
+    fn issue_io_update(&mut self) -> Result<(), Self::Error> {
         self.io_update.set_high().map_err(|_| Error::IOUpdateError)?;
         self.io_update.set_low().map_err(|_| Error::IOUpdateError)
     }
 }
 
+pub trait DoOnGetRefMutData<SPI, CS0, CS1, CS2, GPIO> {
+    fn do_on_get_ref_mut_data<R, E>(
+        &self,
+        f: impl FnOnce(cell::RefMut<CPLDData<SPI, CS0, CS1, CS2, GPIO>>) -> Result<R, Error<E>>,
+    ) -> Result<R, Error<E>>;
+}
+
+impl<SPI, CS0, CS1, CS2, GPIO> DoOnGetRefMutData<SPI, CS0, CS1, CS2, GPIO> for CPLD<SPI, CS0, CS1, CS2, GPIO> {
+    fn do_on_get_ref_mut_data<R, E>(
+        &self,
+        f: impl FnOnce(cell::RefMut<CPLDData<SPI, CS0, CS1, CS2, GPIO>>) -> Result<R, Error<E>>,
+    ) -> Result<R, Error<E>> {
+        let dev = self
+            .data
+            .try_borrow_mut()
+            .map_err(|_| Error::GetRefMutDataError)?;
+        f(dev)
+    }
+}
+
 impl<SPI, CS0, CS1, CS2, GPIO, E> Transfer<u8> for CPLD<SPI, CS0, CS1, CS2, GPIO>
 where
     SPI: Transfer<u8, Error = E>,
@@ -64,7 +106,7 @@ where
     type Error = Error<E>;
 
     fn transfer<'w>(&mut self, words: &'w mut [u8]) -> Result<&'w [u8], Self::Error> {
-        self.data.try_borrow_mut().map_err(|_| Error::GetRefMutDataError)?.spi.transfer(words).map_err(Error::SPI)
+        self.do_on_get_ref_mut_data(move |mut dev| dev.spi.transfer(words).map_err(Error::SPI))
     }
 }
 
@@ -98,7 +140,26 @@ impl<SPI, CS0, CS1, CS2, GPIO, E> CPLD<SPI, CS0, CS1, CS2, GPIO> where
     }
 
     // Split SPI into chips, wrapped by Parts struct
-    pub fn split<'a>(&'a self) -> Parts<'a, SPI, CS0, CS1, CS2, GPIO> {
+    pub fn split<'a>(&'a self) -> Parts<'a, CPLD<SPI, CS0, CS1, CS2, GPIO>, SPI, CS0, CS1, CS2, GPIO> {
         Parts::new(&self)
     }
+
+    // Select Chip
+    pub fn select_chip(&mut self, channel: u8) -> Result<(), Error<E>> {
+        self.do_on_get_ref_mut_data(|mut dev| dev.select_chip(channel))
+    }
+}
+
+impl<SPI, CS0, CS1, CS2, GPIO, E> CPLD<SPI, CS0, CS1, CS2, GPIO>
+where
+    SPI: Transfer<u8>,
+    CS0: OutputPin,
+    CS1: OutputPin,
+    CS2: OutputPin,
+    GPIO: OutputPin<Error = E>
+{	
+    // Issue I/O Update
+    pub fn issue_io_update(&mut self) -> Result<(), Error<E>> {
+        self.do_on_get_ref_mut_data(|mut dev| dev.issue_io_update())
+    }
 }

src/flash.rs

@@ -13,7 +13,6 @@ use nb::block;
 
 use log::{warn, debug};
 
-#[derive(Debug)]
 pub enum FPGAFlashError {
     SPICommunicationError,
     NegotiationError,

src/spi_slave.rs

@@ -4,54 +4,53 @@ use embedded_hal::{
 };
 use core::marker::PhantomData;
 
-use crate::cpld::CPLD;
+use crate::cpld::{DoOnGetRefMutData, SelectChip, IssueIOUpdate};
 use crate::Error;
 
-pub struct SPISlave<'a, SPI, CS0, CS1, CS2, GPIO> (
+pub struct SPISlave<'a, DEV: 'a, SPI, CS0, CS1, CS2, GPIO> (
-	// SPI device to be multiplexed
+	&'a DEV,
-	&'a CPLD<SPI, CS0, CS1, CS2, GPIO>,
+	u8,			// Channel of SPI slave
-	// Channel of SPI slave
+	bool,		// Need I/O Update
-	u8,
+	PhantomData<(SPI, CS0, CS1, CS2, GPIO)>,
-	// Need I/O Update
-	bool,
 );
 
-pub struct Parts<'a, SPI, CS0, CS1, CS2, GPIO> {
+pub struct Parts<'a, DEV: 'a, SPI, CS0, CS1, CS2, GPIO> {
-	pub spi1: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi1: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
-	pub spi2: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi2: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
-	pub spi3: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi3: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
-	pub spi4: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi4: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
-	pub spi5: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi5: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
-	pub spi6: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi6: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
-	pub spi7: SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>,
+	pub spi7: SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>,
 }
 
-impl<'a, SPI, CS0, CS1, CS2, GPIO> Parts<'a, SPI, CS0, CS1, CS2, GPIO> {
+impl<'a, DEV, SPI, CS0, CS1, CS2, GPIO> Parts<'a, DEV, SPI, CS0, CS1, CS2, GPIO> {
-	pub(crate) fn new(cpld: &'a CPLD<SPI, CS0, CS1, CS2, GPIO>) -> Self {
+	pub(crate) fn new(cpld: &'a DEV) -> Self {
 		Parts {
-			spi1: SPISlave(&cpld, 1, false),
+			spi1: SPISlave(&cpld, 1, false, PhantomData),
-			spi2: SPISlave(&cpld, 2, false),
+			spi2: SPISlave(&cpld, 2, false, PhantomData),
-			spi3: SPISlave(&cpld, 3, true),
+			spi3: SPISlave(&cpld, 3, true, PhantomData),
-			spi4: SPISlave(&cpld, 4, true),
+			spi4: SPISlave(&cpld, 4, true, PhantomData),
-			spi5: SPISlave(&cpld, 5, true),
+			spi5: SPISlave(&cpld, 5, true, PhantomData),
-			spi6: SPISlave(&cpld, 6, true),
+			spi6: SPISlave(&cpld, 6, true, PhantomData),
-			spi7: SPISlave(&cpld, 7, true),
+			spi7: SPISlave(&cpld, 7, true, PhantomData),
 		}
 	}
 }
 
-impl<'a, SPI, CS0, CS1, CS2, GPIO, E> Transfer<u8> for SPISlave<'a, SPI, CS0, CS1, CS2, GPIO>
+impl<'a, DEV, SPI, CS0, CS1, CS2, GPIO, E> Transfer<u8> for SPISlave<'a, DEV, SPI, CS0, CS1, CS2, GPIO>
 where
 	CS2: OutputPin,
 	CS1: OutputPin,
 	CS0: OutputPin,
+	DEV: DoOnGetRefMutData<SPI, CS0, CS1, CS2, GPIO>,
 	SPI: Transfer<u8, Error = E>,
 	GPIO: OutputPin,
 {
 	type Error = Error<E>;
 
 	fn transfer<'w>(&mut self, words: &'w mut[u8]) -> Result<&'w [u8], Self::Error> {
-		let mut dev = self.0.data.try_borrow_mut().map_err(|_| Error::GetRefMutDataError)?;
+		self.0.do_on_get_ref_mut_data(move |mut dev| {
 			dev.select_chip(self.1).map_err(|_| Error::CSError)?;
 			let result = dev.spi.transfer(words).map_err(Error::SPI)?;
 			dev.select_chip(0).map_err(|_| Error::CSError)?;
@@ -59,5 +58,6 @@ where
 				dev.issue_io_update().map_err(|_| Error::IOUpdateError)?;
 			}
 			Ok(result)
+		})	
 	}
 }