4 files changed, 125 insertions, 88 deletions

diff --git a/embassy-stm32/src/rtc/low_power.rs b/embassy-stm32/src/rtc/low_power.rs
index a81ac6746..f049d6b12 100644
--- a/embassy-stm32/src/rtc/low_power.rs
+++ b/embassy-stm32/src/rtc/low_power.rs
@@ -1,10 +1,11 @@
 #[cfg(feature = "time")]
 use embassy_time::{Duration, TICK_HZ};
 
-use super::{bcd2_to_byte, DateTimeError, Rtc, RtcError};
+use super::{DateTimeError, Rtc, RtcError, bcd2_to_byte};
 use crate::interrupt::typelevel::Interrupt;
+use crate::pac::rtc::vals::Wucksel;
 use crate::peripherals::RTC;
-use crate::rtc::SealedInstance;
+use crate::rtc::{RtcTimeProvider, SealedInstance};
 
 /// Represents an instant in time that can be substracted to compute a duration
 pub(super) struct RtcInstant {
@@ -58,66 +59,22 @@ impl core::ops::Sub for RtcInstant {
     }
 }
 
-#[repr(u8)]
-#[derive(Clone, Copy, Debug)]
-pub(crate) enum WakeupPrescaler {
-    Div2 = 2,
-    Div4 = 4,
-    Div8 = 8,
-    Div16 = 16,
-}
-
-#[cfg(any(
-    stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba
-))]
-impl From<WakeupPrescaler> for crate::pac::rtc::vals::Wucksel {
-    fn from(val: WakeupPrescaler) -> Self {
-        use crate::pac::rtc::vals::Wucksel;
-
-        match val {
-            WakeupPrescaler::Div2 => Wucksel::DIV2,
-            WakeupPrescaler::Div4 => Wucksel::DIV4,
-            WakeupPrescaler::Div8 => Wucksel::DIV8,
-            WakeupPrescaler::Div16 => Wucksel::DIV16,
-        }
-    }
-}
-
-#[cfg(any(
-    stm32f4, stm32l0, stm32g4, stm32l4, stm32l5, stm32wb, stm32h5, stm32g0, stm32u5, stm32u0, stm32wba
-))]
-impl From<crate::pac::rtc::vals::Wucksel> for WakeupPrescaler {
-    fn from(val: crate::pac::rtc::vals::Wucksel) -> Self {
-        use crate::pac::rtc::vals::Wucksel;
-
-        match val {
-            Wucksel::DIV2 => WakeupPrescaler::Div2,
-            Wucksel::DIV4 => WakeupPrescaler::Div4,
-            Wucksel::DIV8 => WakeupPrescaler::Div8,
-            Wucksel::DIV16 => WakeupPrescaler::Div16,
-            _ => unreachable!(),
-        }
-    }
-}
-
-impl WakeupPrescaler {
-    pub fn compute_min(val: u32) -> Self {
-        *[
-            WakeupPrescaler::Div2,
-            WakeupPrescaler::Div4,
-            WakeupPrescaler::Div8,
-            WakeupPrescaler::Div16,
-        ]
-        .iter()
-        .find(|psc| **psc as u32 > val)
-        .unwrap_or(&WakeupPrescaler::Div16)
-    }
+fn wucksel_compute_min(val: u32) -> (Wucksel, u32) {
+    *[
+        (Wucksel::DIV2, 2),
+        (Wucksel::DIV4, 4),
+        (Wucksel::DIV8, 8),
+        (Wucksel::DIV16, 16),
+    ]
+    .iter()
+    .find(|(_, psc)| *psc as u32 > val)
+    .unwrap_or(&(Wucksel::DIV16, 16))
 }
 
 impl Rtc {
     /// Return the current instant.
     fn instant(&self) -> Result<RtcInstant, RtcError> {
-        self.time_provider().read(|_, tr, ss| {
+        RtcTimeProvider::new().read(|_, tr, ss| {
             let second = bcd2_to_byte((tr.st(), tr.su()));
 
             RtcInstant::from(second, ss).map_err(RtcError::InvalidDateTime)
@@ -127,7 +84,7 @@ impl Rtc {
     /// start the wakeup alarm and with a duration that is as close to but less than
     /// the requested duration, and record the instant the wakeup alarm was started
     pub(crate) fn start_wakeup_alarm(
-        &self,
+        &mut self,
         requested_duration: embassy_time::Duration,
         cs: critical_section::CriticalSection,
     ) {
@@ -138,7 +95,7 @@ impl Rtc {
         let requested_duration = requested_duration.as_ticks().clamp(0, u32::MAX as u64);
         let rtc_hz = Self::frequency().0 as u64;
         let rtc_ticks = requested_duration * rtc_hz / TICK_HZ;
-        let prescaler = WakeupPrescaler::compute_min((rtc_ticks / u16::MAX as u64) as u32);
+        let (wucksel, prescaler) = wucksel_compute_min((rtc_ticks / u16::MAX as u64) as u32);
 
         // adjust the rtc ticks to the prescaler and subtract one rtc tick
         let rtc_ticks = rtc_ticks / prescaler as u64;
@@ -159,7 +116,7 @@ impl Rtc {
                 while !regs.icsr().read().wutwf() {}
             }
 
-            regs.cr().modify(|w| w.set_wucksel(prescaler.into()));
+            regs.cr().modify(|w| w.set_wucksel(wucksel));
             regs.wutr().write(|w| w.set_wut(rtc_ticks));
             regs.cr().modify(|w| w.set_wute(true));
             regs.cr().modify(|w| w.set_wutie(true));
@@ -179,7 +136,10 @@ impl Rtc {
 
     /// stop the wakeup alarm and return the time elapsed since `start_wakeup_alarm`
     /// was called, otherwise none
-    pub(crate) fn stop_wakeup_alarm(&self, cs: critical_section::CriticalSection) -> Option<embassy_time::Duration> {
+    pub(crate) fn stop_wakeup_alarm(
+        &mut self,
+        cs: critical_section::CriticalSection,
+    ) -> Option<embassy_time::Duration> {
         let instant = self.instant().unwrap();
         if RTC::regs().cr().read().wute() {
             trace!("rtc: stop wakeup alarm at {}", instant);
diff --git a/embassy-stm32/src/rtc/mod.rs b/embassy-stm32/src/rtc/mod.rs
index 92dec0960..e88bd7ab2 100644
--- a/embassy-stm32/src/rtc/mod.rs
+++ b/embassy-stm32/src/rtc/mod.rs
@@ -5,15 +5,19 @@ mod datetime;
 mod low_power;
 
 #[cfg(feature = "low-power")]
-use core::cell::Cell;
+use core::cell::{Cell, RefCell, RefMut};
+#[cfg(feature = "low-power")]
+use core::ops;
 
 #[cfg(feature = "low-power")]
-use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
+use critical_section::CriticalSection;
 #[cfg(feature = "low-power")]
 use embassy_sync::blocking_mutex::Mutex;
+#[cfg(feature = "low-power")]
+use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
 
-use self::datetime::{day_of_week_from_u8, day_of_week_to_u8};
 pub use self::datetime::{DateTime, DayOfWeek, Error as DateTimeError};
+use self::datetime::{day_of_week_from_u8, day_of_week_to_u8};
 use crate::pac::rtc::regs::{Dr, Tr};
 use crate::time::Hertz;
 
@@ -25,8 +29,8 @@ mod _version;
 #[allow(unused_imports)]
 pub use _version::*;
 
-use crate::peripherals::RTC;
 use crate::Peri;
+use crate::peripherals::RTC;
 
 /// Errors that can occur on methods on [RtcClock]
 #[non_exhaustive]
@@ -44,11 +48,17 @@ pub enum RtcError {
 }
 
 /// Provides immutable access to the current time of the RTC.
+#[derive(Clone)]
 pub struct RtcTimeProvider {
     _private: (),
 }
 
 impl RtcTimeProvider {
+    /// Create a new RTC time provider instance.
+    pub(self) const fn new() -> Self {
+        Self { _private: () }
+    }
+
     /// Return the current datetime.
     ///
     /// # Errors
@@ -106,6 +116,50 @@ impl RtcTimeProvider {
     }
 }
 
+#[cfg(feature = "low-power")]
+/// Contains an RTC driver.
+pub struct RtcContainer {
+    pub(self) mutex: &'static Mutex<CriticalSectionRawMutex, RefCell<Option<Rtc>>>,
+}
+
+#[cfg(feature = "low-power")]
+impl RtcContainer {
+    pub(self) const fn new() -> Self {
+        Self {
+            mutex: &crate::time_driver::get_driver().rtc,
+        }
+    }
+
+    /// Acquire an RTC borrow.
+    pub fn borrow_mut<'a>(&self, cs: CriticalSection<'a>) -> RtcBorrow<'a> {
+        RtcBorrow {
+            ref_mut: self.mutex.borrow(cs).borrow_mut(),
+        }
+    }
+}
+
+#[cfg(feature = "low-power")]
+/// Contains an RTC borrow.
+pub struct RtcBorrow<'a> {
+    pub(self) ref_mut: RefMut<'a, Option<Rtc>>,
+}
+
+#[cfg(feature = "low-power")]
+impl<'a> ops::Deref for RtcBorrow<'a> {
+    type Target = Rtc;
+
+    fn deref(&self) -> &Self::Target {
+        self.ref_mut.as_ref().unwrap()
+    }
+}
+
+#[cfg(feature = "low-power")]
+impl<'a> ops::DerefMut for RtcBorrow<'a> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        self.ref_mut.as_mut().unwrap()
+    }
+}
+
 /// RTC driver.
 pub struct Rtc {
     #[cfg(feature = "low-power")]
@@ -121,13 +175,21 @@ pub struct RtcConfig {
     ///
     /// A high counter frequency may impact stop power consumption
     pub frequency: Hertz,
+
+    #[cfg(feature = "_allow-disable-rtc")]
+    /// Allow disabling the rtc, even when stop is configured
+    pub _disable_rtc: bool,
 }
 
 impl Default for RtcConfig {
     /// LSI with prescalers assuming 32.768 kHz.
     /// Raw sub-seconds in 1/256.
     fn default() -> Self {
-        RtcConfig { frequency: Hertz(256) }
+        RtcConfig {
+            frequency: Hertz(256),
+            #[cfg(feature = "_allow-disable-rtc")]
+            _disable_rtc: false,
+        }
     }
 }
 
@@ -145,8 +207,19 @@ pub enum RtcCalibrationCyclePeriod {
 }
 
 impl Rtc {
+    #[cfg(not(feature = "low-power"))]
     /// Create a new RTC instance.
-    pub fn new(_rtc: Peri<'static, RTC>, rtc_config: RtcConfig) -> Self {
+    pub fn new(_rtc: Peri<'static, RTC>, rtc_config: RtcConfig) -> (Self, RtcTimeProvider) {
+        (Self::new_inner(rtc_config), RtcTimeProvider::new())
+    }
+
+    #[cfg(feature = "low-power")]
+    /// Create a new RTC instance.
+    pub fn new(_rtc: Peri<'static, RTC>) -> (RtcContainer, RtcTimeProvider) {
+        (RtcContainer::new(), RtcTimeProvider::new())
+    }
+
+    pub(self) fn new_inner(rtc_config: RtcConfig) -> Self {
         #[cfg(not(any(stm32l0, stm32f3, stm32l1, stm32f0, stm32f2)))]
         crate::rcc::enable_and_reset::<RTC>();
 
@@ -165,10 +238,13 @@ impl Rtc {
         // Wait for the clock to update after initialization
         #[cfg(not(rtc_v2_f2))]
         {
-            let now = this.time_provider().read(|_, _, ss| Ok(ss)).unwrap();
-            while now == this.time_provider().read(|_, _, ss| Ok(ss)).unwrap() {}
+            let now = RtcTimeProvider::new().read(|_, _, ss| Ok(ss)).unwrap();
+            while now == RtcTimeProvider::new().read(|_, _, ss| Ok(ss)).unwrap() {}
         }
 
+        #[cfg(feature = "low-power")]
+        this.enable_wakeup_line();
+
         this
     }
 
@@ -177,11 +253,6 @@ impl Rtc {
         freqs.rtc.to_hertz().unwrap()
     }
 
-    /// Acquire a [`RtcTimeProvider`] instance.
-    pub const fn time_provider(&self) -> RtcTimeProvider {
-        RtcTimeProvider { _private: () }
-    }
-
     /// Set the datetime to a new value.
     ///
     /// # Errors
@@ -225,15 +296,6 @@ impl Rtc {
         Ok(())
     }
 
-    /// Return the current datetime.
-    ///
-    /// # Errors
-    ///
-    /// Will return an `RtcError::InvalidDateTime` if the stored value in the system is not a valid [`DayOfWeek`].
-    pub fn now(&self) -> Result<DateTime, RtcError> {
-        self.time_provider().now()
-    }
-
     /// Check if daylight savings time is active.
     pub fn get_daylight_savings(&self) -> bool {
         let cr = RTC::regs().cr().read();
@@ -315,3 +377,18 @@ trait SealedInstance {
 
     // fn apply_config(&mut self, rtc_config: RtcConfig);
 }
+
+#[cfg(feature = "low-power")]
+pub(crate) fn init_rtc(cs: CriticalSection, config: RtcConfig, min_stop_pause: embassy_time::Duration) {
+    use crate::time_driver::get_driver;
+
+    #[cfg(feature = "_allow-disable-rtc")]
+    if config._disable_rtc {
+        return;
+    }
+
+    get_driver().set_rtc(cs, Rtc::new_inner(config));
+    get_driver().set_min_stop_pause(cs, min_stop_pause);
+
+    trace!("low power: stop with rtc configured");
+}
diff --git a/embassy-stm32/src/rtc/v2.rs b/embassy-stm32/src/rtc/v2.rs
index 23f6ccb0c..8ac022536 100644
--- a/embassy-stm32/src/rtc/v2.rs
+++ b/embassy-stm32/src/rtc/v2.rs
@@ -93,7 +93,7 @@ impl super::Rtc {
         })
     }
 
-    pub(super) fn write<F, R>(&self, init_mode: bool, f: F) -> R
+    pub(super) fn write<F, R>(&mut self, init_mode: bool, f: F) -> R
     where
         F: FnOnce(crate::pac::rtc::Rtc) -> R,
     {
diff --git a/embassy-stm32/src/rtc/v3.rs b/embassy-stm32/src/rtc/v3.rs
index d0b52049e..f7ebea73e 100644
--- a/embassy-stm32/src/rtc/v3.rs
+++ b/embassy-stm32/src/rtc/v3.rs
@@ -1,4 +1,4 @@
-use stm32_metapac::rtc::vals::{Calp, Calw16, Calw8, Fmt, Key, Osel, Pol, TampalrmType};
+use stm32_metapac::rtc::vals::{Calp, Calw8, Calw16, Fmt, Key, Osel, Pol, TampalrmType};
 
 use super::RtcCalibrationCyclePeriod;
 use crate::pac::rtc::Rtc;
@@ -95,7 +95,7 @@ impl super::Rtc {
         })
     }
 
-    pub(super) fn write<F, R>(&self, init_mode: bool, f: F) -> R
+    pub(super) fn write<F, R>(&mut self, init_mode: bool, f: F) -> R
     where
         F: FnOnce(crate::pac::rtc::Rtc) -> R,
     {
@@ -131,7 +131,7 @@ impl SealedInstance for crate::peripherals::RTC {
 
     #[cfg(feature = "low-power")]
     cfg_if::cfg_if!(
-        if #[cfg(stm32g4)] {
+        if #[cfg(any(stm32g4, stm32wlex))] {
             const EXTI_WAKEUP_LINE: usize = 20;
         } else if #[cfg(stm32g0)] {
             const EXTI_WAKEUP_LINE: usize = 19;
@@ -142,7 +142,7 @@ impl SealedInstance for crate::peripherals::RTC {
 
     #[cfg(feature = "low-power")]
     cfg_if::cfg_if!(
-        if #[cfg(stm32g4)] {
+        if #[cfg(any(stm32g4, stm32wlex))] {
             type WakeupInterrupt = crate::interrupt::typelevel::RTC_WKUP;
         } else if #[cfg(any(stm32g0, stm32u0))] {
             type WakeupInterrupt = crate::interrupt::typelevel::RTC_TAMP;