From e65503e25537ba872f02137713bdc4e5bf645a13 Mon Sep 17 00:00:00 2001
From: Eric Yanush <ericyanush@icloud.com>
Date: Mon, 22 Apr 2024 13:54:15 -0600
Subject: [PATCH] Add sleep/wakeup handling for bxCAN peripherals

---
 embassy-stm32/src/can/bxcan/mod.rs | 48 +++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/embassy-stm32/src/can/bxcan/mod.rs b/embassy-stm32/src/can/bxcan/mod.rs
index fa408c260..342040c25 100644
--- a/embassy-stm32/src/can/bxcan/mod.rs
+++ b/embassy-stm32/src/can/bxcan/mod.rs
@@ -71,7 +71,10 @@ impl<T: Instance> interrupt::typelevel::Handler<T::SCEInterrupt> for SceInterrup
         let msr = T::regs().msr();
         let msr_val = msr.read();
 
-        if msr_val.erri() {
+        if msr_val.slaki() {
+            msr.modify(|m| m.set_slaki(true));
+            T::state().err_waker.wake();
+        } else if msr_val.erri() {
             info!("Error interrupt");
             // Disable the interrupt, but don't acknowledge the error, so that it can be
             // forwarded off the the bus message consumer. If we don't provide some way for
@@ -251,6 +254,49 @@ impl<'d, T: Instance> Can<'d, T> {
         }
     }
 
+    /// Enables or disables the peripheral from automatically wakeup when a SOF is detected on the bus
+    /// while the peripheral is in sleep mode
+    pub fn set_automatic_wakeup(&mut self, enabled: bool) {
+        Registers(T::regs()).set_automatic_wakeup(enabled);
+    }
+
+    /// Manually wake the peripheral from sleep mode.
+    /// 
+    /// Waking the peripheral manually does not trigger a wake-up interrupt.
+    /// This will wait until the peripheral has acknowledged it has awoken from sleep mode
+    pub fn wakeup(&mut self) {
+        Registers(T::regs()).wakeup()
+    }
+
+    /// Check if the peripheral is currently in sleep mode
+    pub fn is_sleeping(&self) -> bool {
+        T::regs().msr().read().slak()
+    }
+
+    /// Put the peripheral in sleep mode
+    /// 
+    /// When the peripherial is in sleep mode, messages can still be queued for transmission
+    /// and any previously received messages can be read from the receive FIFOs, however
+    /// no messages will be transmitted and no additional messages will be received.
+    /// 
+    /// If the peripheral has automatic wakeup enabled, when a Start-of-Frame is detected
+    /// the peripheral will automatically wake and receive the incoming message.
+    pub async fn sleep(&mut self) {
+        T::regs().ier().modify(|i| i.set_slkie(true));
+        T::regs().mcr().modify(|m| m.set_sleep(true));
+        
+        poll_fn(|cx| {
+            T::state().err_waker.register(cx.waker());
+            if self.is_sleeping() {
+                Poll::Ready(())
+            } else {
+                Poll::Pending
+            }
+        }).await;
+
+        T::regs().ier().modify(|i| i.set_slkie(false));
+    }
+
     /// Queues the message to be sent.
     ///
     /// If the TX queue is full, this will wait until there is space, therefore exerting backpressure.