2 files changed, 28 insertions, 16 deletions

diff --git a/embassy-stm32/src/i2c/mod.rs b/embassy-stm32/src/i2c/mod.rs
index 3303b9f4b..82e28b3ff 100644
--- a/embassy-stm32/src/i2c/mod.rs
+++ b/embassy-stm32/src/i2c/mod.rs
@@ -162,19 +162,32 @@ pub enum SendStatus {
     LeftoverBytes(usize),
 }
 
+struct I2CDropGuard<'d> {
+    info: &'static Info,
+    scl: Option<PeripheralRef<'d, AnyPin>>,
+    sda: Option<PeripheralRef<'d, AnyPin>>,
+}
+impl<'d> Drop for I2CDropGuard<'d> {
+    fn drop(&mut self) {
+        self.scl.as_ref().map(|x| x.set_as_disconnected());
+        self.sda.as_ref().map(|x| x.set_as_disconnected());
+
+        self.info.rcc.disable();
+    }
+}
+
 /// I2C driver.
 pub struct I2c<'d, M: Mode, IM: MasterMode> {
     info: &'static Info,
     state: &'static State,
     kernel_clock: Hertz,
-    scl: Option<PeripheralRef<'d, AnyPin>>,
-    sda: Option<PeripheralRef<'d, AnyPin>>,
     tx_dma: Option<ChannelAndRequest<'d>>,
     rx_dma: Option<ChannelAndRequest<'d>>,
     #[cfg(feature = "time")]
     timeout: Duration,
     _phantom: PhantomData<M>,
     _phantom2: PhantomData<IM>,
+    drop_guard: I2CDropGuard<'d>,
 }
 
 impl<'d> I2c<'d, Async, Master> {
@@ -242,14 +255,17 @@ impl<'d, M: Mode> I2c<'d, M, Master> {
             info: T::info(),
             state: T::state(),
             kernel_clock: T::frequency(),
-            scl,
-            sda,
             tx_dma,
             rx_dma,
             #[cfg(feature = "time")]
             timeout: config.timeout,
             _phantom: PhantomData,
             _phantom2: PhantomData,
+            drop_guard: I2CDropGuard {
+                info: T::info(),
+                scl,
+                sda,
+            },
         };
         this.enable_and_init(freq, config);
 
@@ -271,15 +287,6 @@ impl<'d, M: Mode, IM: MasterMode> I2c<'d, M, IM> {
     }
 }
 
-impl<'d, M: Mode, IM: MasterMode> Drop for I2c<'d, M, IM> {
-    fn drop(&mut self) {
-        self.scl.as_ref().map(|x| x.set_as_disconnected());
-        self.sda.as_ref().map(|x| x.set_as_disconnected());
-
-        self.info.rcc.disable()
-    }
-}
-
 #[derive(Copy, Clone)]
 struct Timeout {
     #[cfg(feature = "time")]
diff --git a/embassy-stm32/src/i2c/v2.rs b/embassy-stm32/src/i2c/v2.rs
index 531358efa..a90bdd551 100644
--- a/embassy-stm32/src/i2c/v2.rs
+++ b/embassy-stm32/src/i2c/v2.rs
@@ -47,6 +47,8 @@ pub(crate) unsafe fn on_interrupt<T: Instance>() {
     critical_section::with(|_| {
         regs.cr1().modify(|w| {
             w.set_addrie(false);
+            w.set_stopie(false);
+            w.set_tcie(false);
             // The flag can only be cleared by writting to nbytes, we won't do that here, so disable
             // the interrupt
             w.set_tcie(false);
@@ -725,14 +727,13 @@ impl<'d, M: Mode> I2c<'d, M, Master> {
             info: self.info,
             state: self.state,
             kernel_clock: self.kernel_clock,
-            scl: self.scl.take(),
-            sda: self.sda.take(),
             tx_dma: self.tx_dma.take(),
             rx_dma: self.rx_dma.take(),
             #[cfg(feature = "time")]
             timeout: self.timeout,
             _phantom: PhantomData,
             _phantom2: PhantomData,
+            drop_guard: self.drop_guard,
         };
         slave.init_slave(slave_addr_config);
         slave
@@ -930,6 +931,8 @@ impl<'d, M: Mode> I2c<'d, M, MultiMaster> {
 
 impl<'d> I2c<'d, Async, MultiMaster> {
     /// Respond to a receive command.
+    ///
+    /// Returns the total number of bytes received.
     pub async fn respond_to_receive(&mut self, buffer: &mut [u8]) -> Result<usize, Error> {
         let timeout = self.timeout();
         timeout.with(self.read_dma_internal_slave(buffer, timeout)).await
@@ -942,6 +945,8 @@ impl<'d> I2c<'d, Async, MultiMaster> {
     }
 
     // for data reception in slave mode
+    //
+    // returns the total number of bytes received
     async fn read_dma_internal_slave(&mut self, buffer: &mut [u8], timeout: Timeout) -> Result<usize, Error> {
         let total_len = buffer.len();
         let mut remaining_len = total_len;
@@ -988,7 +993,7 @@ impl<'d> I2c<'d, Async, MultiMaster> {
                 Poll::Pending
             } else if isr.stopf() {
                 regs.icr().write(|reg| reg.set_stopcf(true));
-                let poll = Poll::Ready(Ok(remaining_len));
+                let poll = Poll::Ready(Ok(total_len - remaining_len));
                 poll
             } else {
                 Poll::Pending