Merge pull request #1356 from embassy-rs/peripheralref-no-mut

Do not require mut in PeripheralRef clone_unchecked, make nRF timer `cc()` borrows less strict.

embassy-hal-common/src/macros.rs

@@ -92,7 +92,7 @@ macro_rules! impl_peripheral {
             type P = $type;
 
             #[inline]
-            unsafe fn clone_unchecked(&mut self) -> Self::P {
+            unsafe fn clone_unchecked(&self) -> Self::P {
                 $type { ..*self }
             }
         }

embassy-hal-common/src/peripheral.rs

@@ -39,7 +39,7 @@ impl<'a, T> PeripheralRef<'a, T> {
     /// You should strongly prefer using `reborrow()` instead. It returns a
     /// `PeripheralRef` that borrows `self`, which allows the borrow checker
     /// to enforce this at compile time.
-    pub unsafe fn clone_unchecked(&mut self) -> PeripheralRef<'a, T>
+    pub unsafe fn clone_unchecked(&self) -> PeripheralRef<'a, T>
     where
         T: Peripheral<P = T>,
     {
@@ -146,14 +146,14 @@ pub trait Peripheral: Sized {
     ///
     /// You should strongly prefer using `into_ref()` instead. It returns a
     /// `PeripheralRef`, which allows the borrow checker to enforce this at compile time.
-    unsafe fn clone_unchecked(&mut self) -> Self::P;
+    unsafe fn clone_unchecked(&self) -> Self::P;
 
     /// Convert a value into a `PeripheralRef`.
     ///
     /// When called on an owned `T`, yields a `PeripheralRef<'static, T>`.
     /// When called on an `&'a mut T`, yields a `PeripheralRef<'a, T>`.
     #[inline]
-    fn into_ref<'a>(mut self) -> PeripheralRef<'a, Self::P>
+    fn into_ref<'a>(self) -> PeripheralRef<'a, Self::P>
     where
         Self: 'a,
     {
@@ -161,14 +161,14 @@ pub trait Peripheral: Sized {
     }
 }
 
-impl<'b, T: DerefMut> Peripheral for T
+impl<'b, T: Deref> Peripheral for T
 where
     T::Target: Peripheral,
 {
     type P = <T::Target as Peripheral>::P;
 
     #[inline]
-    unsafe fn clone_unchecked(&mut self) -> Self::P {
-        self.deref_mut().clone_unchecked()
+    unsafe fn clone_unchecked(&self) -> Self::P {
+        self.deref().clone_unchecked()
     }
 }

embassy-nrf/src/buffered_uarte.rs

@@ -342,7 +342,7 @@ impl<'d, U: UarteInstance, T: TimerInstance> BufferedUarte<'d, U, T> {
         r.enable.write(|w| w.enable().enabled());
 
         // Configure byte counter.
-        let mut timer = Timer::new_counter(timer);
+        let timer = Timer::new_counter(timer);
         timer.cc(1).write(rx_buffer.len() as u32 * 2);
         timer.cc(1).short_compare_clear();
         timer.clear();

embassy-nrf/src/saadc.rs

@@ -315,7 +315,7 @@ impl<'d, const N: usize> Saadc<'d, N> {
             Ppi::new_one_to_one(ppi_ch1, Event::from_reg(&r.events_end), Task::from_reg(&r.tasks_start));
         start_ppi.enable();
 
-        let mut timer = Timer::new(timer);
+        let timer = Timer::new(timer);
         timer.set_frequency(frequency);
         timer.cc(0).write(sample_counter);
         timer.cc(0).short_compare_clear();

embassy-nrf/src/timer.rs

@@ -117,7 +117,7 @@ impl<'d, T: Instance> Timer<'d, T> {
 
         let regs = T::regs();
 
-        let mut this = Self { _p: timer };
+        let this = Self { _p: timer };
 
         // Stop the timer before doing anything else,
         // since changing BITMODE while running can cause 'unpredictable behaviour' according to the specification.
@@ -213,13 +213,13 @@ impl<'d, T: Instance> Timer<'d, T> {
     ///
     /// # Panics
     /// Panics if `n` >= the number of CC registers this timer has (4 for a normal timer, 6 for an extended timer).
-    pub fn cc(&mut self, n: usize) -> Cc<T> {
+    pub fn cc(&self, n: usize) -> Cc<'d, T> {
         if n >= T::CCS {
             panic!("Cannot get CC register {} of timer with {} CC registers.", n, T::CCS);
         }
         Cc {
             n,
-            _p: self._p.reborrow(),
+            _p: unsafe { self._p.clone_unchecked() },
         }
     }
 }

embassy-nrf/src/uarte.rs

@@ -205,7 +205,7 @@ impl<'d, T: Instance> Uarte<'d, T> {
         ppi_ch1: impl Peripheral<P = impl ConfigurableChannel + 'd> + 'd,
         ppi_ch2: impl Peripheral<P = impl ConfigurableChannel + 'd> + 'd,
     ) -> (UarteTx<'d, T>, UarteRxWithIdle<'d, T, U>) {
-        let mut timer = Timer::new(timer);
+        let timer = Timer::new(timer);
 
         into_ref!(ppi_ch1, ppi_ch2);
 

embassy-nrf/src/usb/mod.rs

@@ -153,7 +153,7 @@ impl<'d, T: Instance, V: VbusDetect + 'd> driver::Driver<'d> for Driver<'d, T, V
         }))
     }
 
-    fn start(mut self, control_max_packet_size: u16) -> (Self::Bus, Self::ControlPipe) {
+    fn start(self, control_max_packet_size: u16) -> (Self::Bus, Self::ControlPipe) {
         (
             Bus {
                 _p: unsafe { self._p.clone_unchecked() },

embassy-stm32/build.rs

@@ -180,7 +180,7 @@ fn main() {
 
         #[cfg(flash)]
         impl<'d> FlashLayout<'d> {
-            pub(crate) fn new(mut p: embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>) -> Self {
+            pub(crate) fn new(p: embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>) -> Self {
                 Self {
                     #(#inits),*
                 }

embassy-stm32/src/flash/common.rs

@@ -33,8 +33,7 @@ impl<'d> Flash<'d> {
     }
 
     pub(crate) fn release(self) -> PeripheralRef<'d, crate::peripherals::FLASH> {
-        let mut flash = self;
-        unsafe { flash.inner.clone_unchecked() }
+        unsafe { self.inner.clone_unchecked() }
     }
 }
 

embassy-stm32/src/flash/f4.rs

@@ -67,7 +67,7 @@ mod alt_regions {
 
             // SAFETY: We never expose the cloned peripheral references, and their instance is not public.
             // Also, all flash region operations are protected with a cs.
-            let mut p = self.release();
+            let p = self.release();
             AltFlashLayout {
                 bank1_region1: Bank1Region1(&BANK1_REGION1, unsafe { p.clone_unchecked() }),
                 bank1_region2: Bank1Region2(&BANK1_REGION2, unsafe { p.clone_unchecked() }),

embassy-stm32/src/gpio.rs

@@ -29,7 +29,7 @@ impl<'d, T: Pin> Flex<'d, T> {
     }
 
     #[inline]
-    pub fn degrade(mut self) -> Flex<'d, AnyPin> {
+    pub fn degrade(self) -> Flex<'d, AnyPin> {
         // Safety: We are about to drop the other copy of this pin, so
         // this clone is safe.
         let pin = unsafe { self.pin.clone_unchecked() };