From 38c364473c83f7a6214046d157ea5fe92e758732 Mon Sep 17 00:00:00 2001
From: Emil Fresk <emil.fresk@gmail.com>
Date: Sun, 23 Jun 2024 10:33:02 +0200
Subject: Add blocking version of
 `rtic_sync::arbiter::{i2c,spi}::ArbiterDevice`

---
 rtic-sync/src/arbiter/spi.rs | 164 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 164 insertions(+)
 create mode 100644 rtic-sync/src/arbiter/spi.rs

(limited to 'rtic-sync/src/arbiter/spi.rs')

diff --git a/rtic-sync/src/arbiter/spi.rs b/rtic-sync/src/arbiter/spi.rs
new file mode 100644
index 0000000..7ab15ed
--- /dev/null
+++ b/rtic-sync/src/arbiter/spi.rs
@@ -0,0 +1,164 @@
+//! SPI bus sharing using [`Arbiter`]
+
+use super::Arbiter;
+use embedded_hal::digital::OutputPin;
+use embedded_hal::spi::SpiBus as BlockingSpiBus;
+use embedded_hal_async::{
+    delay::DelayNs,
+    spi::{ErrorType, Operation, SpiBus as AsyncSpiBus, SpiDevice},
+};
+use embedded_hal_bus::spi::DeviceError;
+
+/// [`Arbiter`]-based shared bus implementation.
+pub struct ArbiterDevice<'a, BUS, CS, D> {
+    bus: &'a Arbiter<BUS>,
+    cs: CS,
+    delay: D,
+}
+
+impl<'a, BUS, CS, D> ArbiterDevice<'a, BUS, CS, D> {
+    /// Create a new [`ArbiterDevice`].
+    pub fn new(bus: &'a Arbiter<BUS>, cs: CS, delay: D) -> Self {
+        Self { bus, cs, delay }
+    }
+}
+
+impl<BUS, CS, D> ErrorType for ArbiterDevice<'_, BUS, CS, D>
+where
+    BUS: ErrorType,
+    CS: OutputPin,
+{
+    type Error = DeviceError<BUS::Error, CS::Error>;
+}
+
+impl<Word, BUS, CS, D> SpiDevice<Word> for ArbiterDevice<'_, BUS, CS, D>
+where
+    Word: Copy + 'static,
+    BUS: AsyncSpiBus<Word>,
+    CS: OutputPin,
+    D: DelayNs,
+{
+    async fn transaction(
+        &mut self,
+        operations: &mut [Operation<'_, Word>],
+    ) -> Result<(), DeviceError<BUS::Error, CS::Error>> {
+        let mut bus = self.bus.access().await;
+
+        self.cs.set_low().map_err(DeviceError::Cs)?;
+
+        let op_res = 'ops: {
+            for op in operations {
+                let res = match op {
+                    Operation::Read(buf) => bus.read(buf).await,
+                    Operation::Write(buf) => bus.write(buf).await,
+                    Operation::Transfer(read, write) => bus.transfer(read, write).await,
+                    Operation::TransferInPlace(buf) => bus.transfer_in_place(buf).await,
+                    Operation::DelayNs(ns) => match bus.flush().await {
+                        Err(e) => Err(e),
+                        Ok(()) => {
+                            self.delay.delay_ns(*ns).await;
+                            Ok(())
+                        }
+                    },
+                };
+                if let Err(e) = res {
+                    break 'ops Err(e);
+                }
+            }
+            Ok(())
+        };
+
+        // On failure, it's important to still flush and deassert CS.
+        let flush_res = bus.flush().await;
+        let cs_res = self.cs.set_high();
+
+        op_res.map_err(DeviceError::Spi)?;
+        flush_res.map_err(DeviceError::Spi)?;
+        cs_res.map_err(DeviceError::Cs)?;
+
+        Ok(())
+    }
+}
+
+/// [`Arbiter`]-based shared bus implementation.
+pub struct BlockingArbiterDevice<'a, BUS, CS, D> {
+    bus: &'a Arbiter<BUS>,
+    cs: CS,
+    delay: D,
+}
+
+impl<'a, BUS, CS, D> BlockingArbiterDevice<'a, BUS, CS, D> {
+    /// Create a new [`BlockingArbiterDevice`].
+    pub fn new(bus: &'a Arbiter<BUS>, cs: CS, delay: D) -> Self {
+        Self { bus, cs, delay }
+    }
+
+    /// Create an `ArbiterDevice` from an `BlockingArbiterDevice`.
+    pub fn into_non_blocking(self) -> ArbiterDevice<'a, BUS, CS, D>
+    where
+        BUS: AsyncSpiBus,
+    {
+        ArbiterDevice {
+            bus: self.bus,
+            cs: self.cs,
+            delay: self.delay,
+        }
+    }
+}
+
+impl<'a, BUS, CS, D> ErrorType for BlockingArbiterDevice<'a, BUS, CS, D>
+where
+    BUS: ErrorType,
+    CS: OutputPin,
+{
+    type Error = DeviceError<BUS::Error, CS::Error>;
+}
+
+impl<'a, Word, BUS, CS, D> SpiDevice<Word> for BlockingArbiterDevice<'a, BUS, CS, D>
+where
+    Word: Copy + 'static,
+    BUS: BlockingSpiBus<Word>,
+    CS: OutputPin,
+    D: DelayNs,
+{
+    async fn transaction(
+        &mut self,
+        operations: &mut [Operation<'_, Word>],
+    ) -> Result<(), DeviceError<BUS::Error, CS::Error>> {
+        let mut bus = self.bus.access().await;
+
+        self.cs.set_low().map_err(DeviceError::Cs)?;
+
+        let op_res = 'ops: {
+            for op in operations {
+                let res = match op {
+                    Operation::Read(buf) => bus.read(buf),
+                    Operation::Write(buf) => bus.write(buf),
+                    Operation::Transfer(read, write) => bus.transfer(read, write),
+                    Operation::TransferInPlace(buf) => bus.transfer_in_place(buf),
+                    Operation::DelayNs(ns) => match bus.flush() {
+                        Err(e) => Err(e),
+                        Ok(()) => {
+                            self.delay.delay_ns(*ns).await;
+                            Ok(())
+                        }
+                    },
+                };
+                if let Err(e) = res {
+                    break 'ops Err(e);
+                }
+            }
+            Ok(())
+        };
+
+        // On failure, it's important to still flush and deassert CS.
+        let flush_res = bus.flush();
+        let cs_res = self.cs.set_high();
+
+        op_res.map_err(DeviceError::Spi)?;
+        flush_res.map_err(DeviceError::Spi)?;
+        cs_res.map_err(DeviceError::Cs)?;
+
+        Ok(())
+    }
+}
-- 
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