stm32/rcc: add LSE/LSI to all chips, add RTC to more chips.

31 files changed, 266 insertions, 402 deletions

diff --git a/embassy-stm32/Cargo.toml b/embassy-stm32/Cargo.toml
index 6137e3c02..33583d22b 100644
--- a/embassy-stm32/Cargo.toml
+++ b/embassy-stm32/Cargo.toml
@@ -59,7 +59,7 @@ sdio-host = "0.5.0"
 embedded-sdmmc = { git = "https://github.com/embassy-rs/embedded-sdmmc-rs", rev = "a4f293d3a6f72158385f79c98634cb8a14d0d2fc", optional = true }
 critical-section = "1.1"
 atomic-polyfill = "1.0.1"
-stm32-metapac = { git = "https://github.com/embassy-rs/stm32-data-generated", tag = "stm32-data-9f45b0c48cc3de71ec6a66fe7e871b21aef0940c" }
+stm32-metapac = { git = "https://github.com/embassy-rs/stm32-data-generated", tag = "stm32-data-6bfa5a0dcec6a9bd42cea94ba11eeae1a17a7f2c" }
 vcell = "0.1.3"
 bxcan = "0.7.0"
 nb = "1.0.0"
@@ -77,7 +77,7 @@ critical-section = { version = "1.1", features = ["std"] }
 [build-dependencies]
 proc-macro2 = "1.0.36"
 quote = "1.0.15"
-stm32-metapac = { git = "https://github.com/embassy-rs/stm32-data-generated", tag = "stm32-data-9f45b0c48cc3de71ec6a66fe7e871b21aef0940c", default-features = false, features = ["metadata"]}
+stm32-metapac = { git = "https://github.com/embassy-rs/stm32-data-generated", tag = "stm32-data-6bfa5a0dcec6a9bd42cea94ba11eeae1a17a7f2c", default-features = false, features = ["metadata"]}
 
 
 [features]
diff --git a/embassy-stm32/src/rcc/bd.rs b/embassy-stm32/src/rcc/bd.rs
index c18e92bc8..66ca65f80 100644
--- a/embassy-stm32/src/rcc/bd.rs
+++ b/embassy-stm32/src/rcc/bd.rs
@@ -1,14 +1,24 @@
+use core::sync::atomic::{compiler_fence, Ordering};
+
+use crate::pac::common::{Reg, RW};
+pub use crate::pac::rcc::vals::Rtcsel as RtcClockSource;
+use crate::time::Hertz;
+
+#[cfg(any(stm32f0, stm32f1, stm32f3))]
+pub const LSI_FREQ: Hertz = Hertz(40_000);
+#[cfg(not(any(stm32f0, stm32f1, stm32f3)))]
+pub const LSI_FREQ: Hertz = Hertz(32_000);
+
 #[allow(dead_code)]
 #[derive(Clone, Copy)]
-pub enum LseCfg {
+pub enum LseMode {
     Oscillator(LseDrive),
     Bypass,
 }
 
-impl Default for LseCfg {
-    fn default() -> Self {
-        Self::Oscillator(Default::default())
-    }
+pub struct LseConfig {
+    pub frequency: Hertz,
+    pub mode: LseMode,
 }
 
 #[allow(dead_code)]
@@ -36,90 +46,116 @@ impl From<LseDrive> for crate::pac::rcc::vals::Lsedrv {
     }
 }
 
-pub use crate::pac::rcc::vals::Rtcsel as RtcClockSource;
-
 #[cfg(not(any(rtc_v2l0, rtc_v2l1, stm32c0)))]
-#[allow(dead_code)]
 type Bdcr = crate::pac::rcc::regs::Bdcr;
-
 #[cfg(any(rtc_v2l0, rtc_v2l1))]
-#[allow(dead_code)]
 type Bdcr = crate::pac::rcc::regs::Csr;
+#[cfg(any(stm32c0))]
+type Bdcr = crate::pac::rcc::regs::Csr1;
+
+#[cfg(any(stm32c0))]
+fn unlock() {}
+
+#[cfg(not(any(stm32c0)))]
+fn unlock() {
+    #[cfg(any(stm32f0, stm32f1, stm32f2, stm32f3, stm32l0, stm32l1))]
+    let cr = crate::pac::PWR.cr();
+    #[cfg(not(any(stm32f0, stm32f1, stm32f2, stm32f3, stm32l0, stm32l1, stm32u5, stm32h5, stm32wba)))]
+    let cr = crate::pac::PWR.cr1();
+    #[cfg(any(stm32u5, stm32h5, stm32wba))]
+    let cr = crate::pac::PWR.dbpcr();
+
+    cr.modify(|w| w.set_dbp(true));
+    while !cr.read().dbp() {}
+}
 
-#[allow(dead_code)]
-pub struct BackupDomain {}
-
-impl BackupDomain {
-    #[cfg(any(
-        rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb, rtc_v3,
-        rtc_v3u5
-    ))]
-    #[allow(dead_code, unused_variables)]
-    fn modify<R>(f: impl FnOnce(&mut Bdcr) -> R) -> R {
-        #[cfg(any(rtc_v2f2, rtc_v2f3, rtc_v2l1, rtc_v2l0))]
-        let cr = crate::pac::PWR.cr();
-        #[cfg(any(rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l4, rtc_v2wb, rtc_v3, rtc_v3u5))]
-        let cr = crate::pac::PWR.cr1();
-
-        // TODO: Missing from PAC for l0 and f0?
-        #[cfg(not(any(rtc_v2f0, rtc_v3u5)))]
-        {
-            cr.modify(|w| w.set_dbp(true));
-            while !cr.read().dbp() {}
-        }
+fn bdcr() -> Reg<Bdcr, RW> {
+    #[cfg(any(rtc_v2l0, rtc_v2l1))]
+    return crate::pac::RCC.csr();
+    #[cfg(not(any(rtc_v2l0, rtc_v2l1, stm32c0)))]
+    return crate::pac::RCC.bdcr();
+    #[cfg(any(stm32c0))]
+    return crate::pac::RCC.csr1();
+}
 
-        #[cfg(any(rtc_v2l0, rtc_v2l1))]
-        let cr = crate::pac::RCC.csr();
+pub struct LsConfig {
+    pub rtc: RtcClockSource,
+    pub lsi: bool,
+    pub lse: Option<LseConfig>,
+}
 
-        #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
-        let cr = crate::pac::RCC.bdcr();
+impl LsConfig {
+    pub const fn default_lse() -> Self {
+        Self {
+            rtc: RtcClockSource::LSE,
+            lse: Some(LseConfig {
+                frequency: Hertz(32_000),
+                mode: LseMode::Oscillator(LseDrive::MediumHigh),
+            }),
+            lsi: false,
+        }
+    }
 
-        cr.modify(|w| f(w))
+    pub const fn default_lsi() -> Self {
+        Self {
+            rtc: RtcClockSource::LSI,
+            lsi: true,
+            lse: None,
+        }
     }
 
-    #[cfg(any(
-        rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb, rtc_v3,
-        rtc_v3u5
-    ))]
-    #[allow(dead_code)]
-    fn read() -> Bdcr {
-        #[cfg(any(rtc_v2l0, rtc_v2l1))]
-        let r = crate::pac::RCC.csr().read();
+    pub const fn off() -> Self {
+        Self {
+            rtc: RtcClockSource::NOCLOCK,
+            lsi: false,
+            lse: None,
+        }
+    }
+}
 
-        #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
-        let r = crate::pac::RCC.bdcr().read();
+impl Default for LsConfig {
+    fn default() -> Self {
+        // on L5, just the fact that LSI is enabled makes things crash.
+        // TODO: investigate.
 
-        r
+        #[cfg(not(stm32l5))]
+        return Self::default_lsi();
+        #[cfg(stm32l5)]
+        return Self::off();
     }
+}
 
-    #[cfg(any(
-        rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb, rtc_v3,
-        rtc_v3u5
-    ))]
-    #[allow(dead_code, unused_variables)]
-    pub fn configure_ls(clock_source: RtcClockSource, lsi: bool, lse: Option<LseCfg>) {
-        use atomic_polyfill::{compiler_fence, Ordering};
-
-        match clock_source {
-            RtcClockSource::LSI => assert!(lsi),
-            RtcClockSource::LSE => assert!(lse.is_some()),
-            _ => {}
+impl LsConfig {
+    pub(crate) fn init(&self) -> Option<Hertz> {
+        let rtc_clk = match self.rtc {
+            RtcClockSource::LSI => {
+                assert!(self.lsi);
+                Some(LSI_FREQ)
+            }
+            RtcClockSource::LSE => Some(self.lse.as_ref().unwrap().frequency),
+            RtcClockSource::NOCLOCK => None,
+            _ => todo!(),
         };
-        let (lse_en, lse_byp, lse_drv) = match lse {
-            Some(LseCfg::Oscillator(lse_drv)) => (true, false, Some(lse_drv)),
-            Some(LseCfg::Bypass) => (true, true, None),
+
+        let (lse_en, lse_byp, lse_drv) = match &self.lse {
+            Some(c) => match c.mode {
+                LseMode::Oscillator(lse_drv) => (true, false, Some(lse_drv)),
+                LseMode::Bypass => (true, true, None),
+            },
             None => (false, false, None),
         };
+        _ = lse_drv; // not all chips have it.
 
-        if lsi {
-            #[cfg(rtc_v3u5)]
-            let csr = crate::pac::RCC.bdcr();
+        // Disable backup domain write protection
+        unlock();
 
-            #[cfg(not(rtc_v3u5))]
+        if self.lsi {
+            #[cfg(any(stm32u5, stm32h5, stm32wba))]
+            let csr = crate::pac::RCC.bdcr();
+            #[cfg(not(any(stm32u5, stm32h5, stm32wba, stm32c0)))]
             let csr = crate::pac::RCC.csr();
-
-            // Disable backup domain write protection
-            Self::modify(|_| {});
+            #[cfg(any(stm32c0))]
+            let csr = crate::pac::RCC.csr2();
 
             #[cfg(not(any(rcc_wb, rcc_wba)))]
             csr.modify(|w| w.set_lsion(true));
@@ -139,12 +175,12 @@ impl BackupDomain {
         // first check if the configuration matches what we want.
 
         // check if it's already enabled and in the source we want.
-        let reg = Self::read();
+        let reg = bdcr().read();
         let mut ok = true;
-        ok &= reg.rtcsel() == clock_source;
+        ok &= reg.rtcsel() == self.rtc;
         #[cfg(not(rcc_wba))]
         {
-            ok &= reg.rtcen() == (clock_source != RtcClockSource::NOCLOCK);
+            ok &= reg.rtcen() == (self.rtc != RtcClockSource::NOCLOCK);
         }
         ok &= reg.lseon() == lse_en;
         ok &= reg.lsebyp() == lse_byp;
@@ -155,22 +191,29 @@ impl BackupDomain {
 
         // if configuration is OK, we're done.
         if ok {
-            // RTC code assumes backup domain is unlocked
-            Self::modify(|w| {});
-
-            trace!("BDCR ok: {:08x}", Self::read().0);
-            return;
+            trace!("BDCR ok: {:08x}", bdcr().read().0);
+            return rtc_clk;
         }
 
         // If not OK, reset backup domain and configure it.
-        #[cfg(not(any(rcc_l0, rcc_l0_v2, rcc_l1)))]
+        #[cfg(not(any(rcc_l0, rcc_l0_v2, rcc_l1, stm32h5, stm32c0)))]
+        {
+            bdcr().modify(|w| w.set_bdrst(true));
+            bdcr().modify(|w| w.set_bdrst(false));
+        }
+        #[cfg(any(stm32h5))]
+        {
+            bdcr().modify(|w| w.set_vswrst(true));
+            bdcr().modify(|w| w.set_vswrst(false));
+        }
+        #[cfg(any(stm32c0))]
         {
-            Self::modify(|w| w.set_bdrst(true));
-            Self::modify(|w| w.set_bdrst(false));
+            bdcr().modify(|w| w.set_rtcrst(true));
+            bdcr().modify(|w| w.set_rtcrst(false));
         }
 
         if lse_en {
-            Self::modify(|w| {
+            bdcr().modify(|w| {
                 #[cfg(not(any(rcc_f1, rcc_f1cl, rcc_f100, rcc_f2, rcc_f4, rcc_f400, rcc_f410, rcc_l1)))]
                 if let Some(lse_drv) = lse_drv {
                     w.set_lsedrv(lse_drv.into());
@@ -179,22 +222,24 @@ impl BackupDomain {
                 w.set_lseon(true);
             });
 
-            while !Self::read().lserdy() {}
+            while !bdcr().read().lserdy() {}
         }
 
-        if clock_source != RtcClockSource::NOCLOCK {
-            Self::modify(|w| {
+        if self.rtc != RtcClockSource::NOCLOCK {
+            bdcr().modify(|w| {
                 #[cfg(any(rtc_v2h7, rtc_v2l4, rtc_v2wb, rtc_v3, rtc_v3u5))]
                 assert!(!w.lsecsson(), "RTC is not compatible with LSE CSS, yet.");
 
                 #[cfg(not(rcc_wba))]
                 w.set_rtcen(true);
-                w.set_rtcsel(clock_source);
+                w.set_rtcsel(self.rtc);
             });
         }
 
-        trace!("BDCR configured: {:08x}", Self::read().0);
+        trace!("BDCR configured: {:08x}", bdcr().read().0);
 
         compiler_fence(Ordering::SeqCst);
+
+        rtc_clk
     }
 }
diff --git a/embassy-stm32/src/rcc/c0.rs b/embassy-stm32/src/rcc/c0.rs
index 34d339a78..eeb6418ae 100644
--- a/embassy-stm32/src/rcc/c0.rs
+++ b/embassy-stm32/src/rcc/c0.rs
@@ -8,9 +8,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(48_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// System clock mux source
 #[derive(Clone, Copy)]
 pub enum ClockSrc {
@@ -24,6 +21,7 @@ pub struct Config {
     pub mux: ClockSrc,
     pub ahb_pre: AHBPrescaler,
     pub apb_pre: APBPrescaler,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -33,6 +31,7 @@ impl Default for Config {
             mux: ClockSrc::HSI(HSIPrescaler::DIV1),
             ahb_pre: AHBPrescaler::DIV1,
             apb_pre: APBPrescaler::DIV1,
+            ls: Default::default(),
         }
     }
 }
@@ -60,10 +59,12 @@ pub(crate) unsafe fn init(config: Config) {
             // Enable LSI
             RCC.csr2().write(|w| w.set_lsion(true));
             while !RCC.csr2().read().lsirdy() {}
-            (LSI_FREQ, Sw::LSI)
+            (super::LSI_FREQ, Sw::LSI)
         }
     };
 
+    let rtc = config.ls.init();
+
     // Determine the flash latency implied by the target clock speed
     // RM0454 § 3.3.4:
     let target_flash_latency = if sys_clk <= Hertz(24_000_000) {
@@ -137,5 +138,6 @@ pub(crate) unsafe fn init(config: Config) {
         ahb1: ahb_freq,
         apb1: apb_freq,
         apb1_tim: apb_tim_freq,
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/f0.rs b/embassy-stm32/src/rcc/f0.rs
index ca6eed284..cc712e87a 100644
--- a/embassy-stm32/src/rcc/f0.rs
+++ b/embassy-stm32/src/rcc/f0.rs
@@ -8,9 +8,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(8_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(40_000);
-
 /// Configuration of the clocks
 ///
 /// hse takes precedence over hsi48 if both are enabled
@@ -27,6 +24,8 @@ pub struct Config {
     pub sys_ck: Option<Hertz>,
     pub hclk: Option<Hertz>,
     pub pclk: Option<Hertz>,
+
+    pub ls: super::LsConfig,
 }
 
 pub(crate) unsafe fn init(config: Config) {
@@ -159,6 +158,8 @@ pub(crate) unsafe fn init(config: Config) {
         })
     }
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: Hertz(real_sysclk),
         apb1: Hertz(pclk),
@@ -166,5 +167,6 @@ pub(crate) unsafe fn init(config: Config) {
         apb1_tim: Hertz(pclk * timer_mul),
         apb2_tim: Hertz(pclk * timer_mul),
         ahb1: Hertz(hclk),
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/f1.rs b/embassy-stm32/src/rcc/f1.rs
index 081c0c767..56c49cd8e 100644
--- a/embassy-stm32/src/rcc/f1.rs
+++ b/embassy-stm32/src/rcc/f1.rs
@@ -9,9 +9,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(8_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(40_000);
-
 /// Configuration of the clocks
 ///
 #[non_exhaustive]
@@ -25,6 +22,8 @@ pub struct Config {
     pub pclk2: Option<Hertz>,
     pub adcclk: Option<Hertz>,
     pub pllxtpre: bool,
+
+    pub ls: super::LsConfig,
 }
 
 pub(crate) unsafe fn init(config: Config) {
@@ -177,6 +176,8 @@ pub(crate) unsafe fn init(config: Config) {
         });
     });
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: Hertz(real_sysclk),
         apb1: Hertz(pclk1),
@@ -185,5 +186,6 @@ pub(crate) unsafe fn init(config: Config) {
         apb2_tim: Hertz(pclk2 * timer_mul2),
         ahb1: Hertz(hclk),
         adc: Some(Hertz(adcclk)),
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/f2.rs b/embassy-stm32/src/rcc/f2.rs
index 478d8894f..ab588233f 100644
--- a/embassy-stm32/src/rcc/f2.rs
+++ b/embassy-stm32/src/rcc/f2.rs
@@ -5,17 +5,12 @@ pub use crate::pac::rcc::vals::{
     Ppre as APBPrescaler,
 };
 use crate::pac::{FLASH, RCC};
-use crate::rcc::bd::BackupDomain;
 use crate::rcc::{set_freqs, Clocks};
-use crate::rtc::RtcClockSource;
 use crate::time::Hertz;
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 #[derive(Clone, Copy)]
 pub struct HSEConfig {
     pub frequency: Hertz,
@@ -180,13 +175,11 @@ pub struct Config {
     pub pll_mux: PLLSrc,
     pub pll: PLLConfig,
     pub mux: ClockSrc,
-    pub rtc: Option<RtcClockSource>,
-    pub lsi: bool,
-    pub lse: Option<Hertz>,
     pub voltage: VoltageScale,
     pub ahb_pre: AHBPrescaler,
     pub apb1_pre: APBPrescaler,
     pub apb2_pre: APBPrescaler,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -199,12 +192,10 @@ impl Default for Config {
             pll: PLLConfig::default(),
             voltage: VoltageScale::Range3,
             mux: ClockSrc::HSI,
-            rtc: None,
-            lsi: false,
-            lse: None,
             ahb_pre: AHBPrescaler::DIV1,
             apb1_pre: APBPrescaler::DIV1,
             apb2_pre: APBPrescaler::DIV1,
+            ls: Default::default(),
         }
     }
 }
@@ -312,11 +303,7 @@ pub(crate) unsafe fn init(config: Config) {
         RCC.cr().modify(|w| w.set_hsion(false));
     }
 
-    BackupDomain::configure_ls(
-        config.rtc.unwrap_or(RtcClockSource::NOCLOCK),
-        config.lsi,
-        config.lse.map(|_| Default::default()),
-    );
+    let rtc = config.ls.init();
 
     set_freqs(Clocks {
         sys: sys_clk,
@@ -328,5 +315,6 @@ pub(crate) unsafe fn init(config: Config) {
         apb2: apb2_freq,
         apb2_tim: apb2_tim_freq,
         pll48: Some(pll_clocks.pll48_freq),
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/f3.rs b/embassy-stm32/src/rcc/f3.rs
index a11eeee54..2aa79cec7 100644
--- a/embassy-stm32/src/rcc/f3.rs
+++ b/embassy-stm32/src/rcc/f3.rs
@@ -10,9 +10,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(8_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(40_000);
-
 #[cfg(rcc_f3)]
 impl From<AdcClockSource> for Ckmode {
     fn from(value: AdcClockSource) -> Self {
@@ -87,6 +84,7 @@ pub struct Config {
     pub adc34: Option<AdcClockSource>,
     #[cfg(stm32f334)]
     pub hrtim: HrtimClockSource,
+    pub ls: super::LsConfig,
 }
 
 // Information required to setup the PLL clock
@@ -279,6 +277,8 @@ pub(crate) unsafe fn init(config: Config) {
         }
     };
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: sysclk,
         apb1: pclk1,
@@ -294,6 +294,7 @@ pub(crate) unsafe fn init(config: Config) {
         adc34: None,
         #[cfg(stm32f334)]
         hrtim: hrtim,
+        rtc,
     });
 }
 
diff --git a/embassy-stm32/src/rcc/f4.rs b/embassy-stm32/src/rcc/f4.rs
index 754a0d570..79c2d2f66 100644
--- a/embassy-stm32/src/rcc/f4.rs
+++ b/embassy-stm32/src/rcc/f4.rs
@@ -1,17 +1,11 @@
-use stm32_metapac::rcc::vals::{Pllm, Plln, Pllq, Pllr};
-
-use crate::pac::rcc::vals::{Hpre, Ppre, Sw};
+use crate::pac::rcc::vals::{Hpre, Pllm, Plln, Pllq, Pllr, Ppre, Sw};
 use crate::pac::{FLASH, PWR, RCC};
-use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// Clocks configuration
 #[non_exhaustive]
 #[derive(Default)]
@@ -30,9 +24,7 @@ pub struct Config {
     pub pllsai: Option<Hertz>,
 
     pub pll48: bool,
-    pub rtc: Option<RtcClockSource>,
-    pub lsi: bool,
-    pub lse: Option<Hertz>,
+    pub ls: super::LsConfig,
 }
 
 #[cfg(stm32f410)]
@@ -344,17 +336,7 @@ pub(crate) unsafe fn init(config: Config) {
         })
     });
 
-    BackupDomain::configure_ls(
-        config.rtc.unwrap_or(RtcClockSource::NOCLOCK),
-        config.lsi,
-        config.lse.map(|_| Default::default()),
-    );
-
-    let rtc = match config.rtc {
-        Some(RtcClockSource::LSI) => Some(LSI_FREQ),
-        Some(RtcClockSource::LSE) => Some(config.lse.unwrap()),
-        _ => None,
-    };
+    let rtc = config.ls.init();
 
     set_freqs(Clocks {
         sys: Hertz(sysclk),
@@ -377,7 +359,6 @@ pub(crate) unsafe fn init(config: Config) {
         pllsai: plls.pllsaiclk.map(Hertz),
 
         rtc,
-        rtc_hse: None,
     });
 }
 
diff --git a/embassy-stm32/src/rcc/f7.rs b/embassy-stm32/src/rcc/f7.rs
index 565f6aa9f..0a0a1cf28 100644
--- a/embassy-stm32/src/rcc/f7.rs
+++ b/embassy-stm32/src/rcc/f7.rs
@@ -1,16 +1,12 @@
 use crate::pac::pwr::vals::Vos;
 use crate::pac::rcc::vals::{Hpre, Pllm, Plln, Pllp, Pllq, Pllsrc, Ppre, Sw};
 use crate::pac::{FLASH, PWR, RCC};
-use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// Clocks configuration
 #[non_exhaustive]
 #[derive(Default)]
@@ -23,9 +19,7 @@ pub struct Config {
     pub pclk2: Option<Hertz>,
 
     pub pll48: bool,
-    pub rtc: Option<RtcClockSource>,
-    pub lsi: bool,
-    pub lse: Option<Hertz>,
+    pub ls: super::LsConfig,
 }
 
 fn setup_pll(pllsrcclk: u32, use_hse: bool, pllsysclk: Option<u32>, pll48clk: bool) -> PllResults {
@@ -261,17 +255,7 @@ pub(crate) unsafe fn init(config: Config) {
         })
     });
 
-    BackupDomain::configure_ls(
-        config.rtc.unwrap_or(RtcClockSource::NOCLOCK),
-        config.lsi,
-        config.lse.map(|_| Default::default()),
-    );
-
-    let rtc = match config.rtc {
-        Some(RtcClockSource::LSI) => Some(LSI_FREQ),
-        Some(RtcClockSource::LSE) => Some(config.lse.unwrap()),
-        _ => None,
-    };
+    let rtc = config.ls.init();
 
     set_freqs(Clocks {
         sys: Hertz(sysclk),
diff --git a/embassy-stm32/src/rcc/g0.rs b/embassy-stm32/src/rcc/g0.rs
index 823836af7..962b1dc0d 100644
--- a/embassy-stm32/src/rcc/g0.rs
+++ b/embassy-stm32/src/rcc/g0.rs
@@ -10,9 +10,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// System clock mux source
 #[derive(Clone, Copy)]
 pub enum ClockSrc {
@@ -73,6 +70,7 @@ pub struct Config {
     pub ahb_pre: AHBPrescaler,
     pub apb_pre: APBPrescaler,
     pub low_power_run: bool,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -83,6 +81,7 @@ impl Default for Config {
             ahb_pre: AHBPrescaler::DIV1,
             apb_pre: APBPrescaler::DIV1,
             low_power_run: false,
+            ls: Default::default(),
         }
     }
 }
@@ -193,7 +192,7 @@ pub(crate) unsafe fn init(config: Config) {
             // Enable LSI
             RCC.csr().write(|w| w.set_lsion(true));
             while !RCC.csr().read().lsirdy() {}
-            (LSI_FREQ, Sw::LSI)
+            (super::LSI_FREQ, Sw::LSI)
         }
     };
 
@@ -272,10 +271,13 @@ pub(crate) unsafe fn init(config: Config) {
         PWR.cr1().modify(|w| w.set_lpr(true));
     }
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: sys_clk,
         ahb1: ahb_freq,
         apb1: apb_freq,
         apb1_tim: apb_tim_freq,
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/g4.rs b/embassy-stm32/src/rcc/g4.rs
index 43256524d..a4078e38b 100644
--- a/embassy-stm32/src/rcc/g4.rs
+++ b/embassy-stm32/src/rcc/g4.rs
@@ -14,9 +14,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// System clock mux source
 #[derive(Clone, Copy)]
 pub enum ClockSrc {
@@ -101,6 +98,8 @@ pub struct Config {
     pub clock_48mhz_src: Option<Clock48MhzSrc>,
     pub adc12_clock_source: AdcClockSource,
     pub adc345_clock_source: AdcClockSource,
+
+    pub ls: super::LsConfig,
 }
 
 /// Configuration for the Clock Recovery System (CRS) used to trim the HSI48 oscillator.
@@ -122,6 +121,7 @@ impl Default for Config {
             clock_48mhz_src: None,
             adc12_clock_source: Adcsel::NOCLK,
             adc345_clock_source: Adcsel::NOCLK,
+            ls: Default::default(),
         }
     }
 }
@@ -344,6 +344,8 @@ pub(crate) unsafe fn init(config: Config) {
         PWR.cr1().modify(|w| w.set_lpr(true));
     }
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: sys_clk,
         ahb1: ahb_freq,
@@ -354,5 +356,6 @@ pub(crate) unsafe fn init(config: Config) {
         apb2_tim: apb2_tim_freq,
         adc: adc12_ck,
         adc34: adc345_ck,
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/h.rs b/embassy-stm32/src/rcc/h.rs
index d29064996..7236d82ff 100644
--- a/embassy-stm32/src/rcc/h.rs
+++ b/embassy-stm32/src/rcc/h.rs
@@ -9,8 +9,6 @@ pub use crate::pac::rcc::vals::Adcsel as AdcClockSource;
 use crate::pac::rcc::vals::{Ckpersel, Hsidiv, Pllrge, Pllsrc, Pllvcosel, Sw, Timpre};
 pub use crate::pac::rcc::vals::{Ckpersel as PerClockSource, Plldiv as PllDiv, Pllm as PllPreDiv, Plln as PllMul};
 use crate::pac::{FLASH, PWR, RCC};
-#[cfg(stm32h7)]
-use crate::rcc::bd::{BackupDomain, LseCfg, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
 
@@ -23,9 +21,6 @@ pub const CSI_FREQ: Hertz = Hertz(4_000_000);
 /// HSI48 speed
 pub const HSI48_FREQ: Hertz = Hertz(48_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 const VCO_RANGE: RangeInclusive<Hertz> = Hertz(150_000_000)..=Hertz(420_000_000);
 #[cfg(any(stm32h5, pwr_h7rm0455))]
 const VCO_WIDE_RANGE: RangeInclusive<Hertz> = Hertz(128_000_000)..=Hertz(560_000_000);
@@ -196,8 +191,7 @@ pub struct Config {
     pub adc_clock_source: AdcClockSource,
     pub timer_prescaler: TimerPrescaler,
     pub voltage_scale: VoltageScale,
-    #[cfg(stm32h7)]
-    pub rtc_mux: Option<RtcClockSource>,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -231,8 +225,7 @@ impl Default for Config {
             adc_clock_source: AdcClockSource::from_bits(0), // PLL2_P on H7, HCLK on H5
             timer_prescaler: TimerPrescaler::DefaultX2,
             voltage_scale: VoltageScale::Scale0,
-            #[cfg(stm32h7)]
-            rtc_mux: None,
+            ls: Default::default(),
         }
     }
 }
@@ -471,18 +464,7 @@ pub(crate) unsafe fn init(config: Config) {
 
     flash_setup(hclk, config.voltage_scale);
 
-    #[cfg(stm32h7)]
-    {
-        let lsecfg = config.lse.map(|lse| match lse {
-            Lse::Bypass(freq) => {
-                assert!(freq <= Hertz(1_000_000));
-                LseCfg::Bypass
-            }
-            Lse::Oscillator => LseCfg::Oscillator(Default::default()),
-        });
-
-        BackupDomain::configure_ls(config.rtc_mux.unwrap_or(RtcClockSource::NOCLOCK), config.lsi, lsecfg);
-    }
+    let rtc = config.ls.init();
 
     #[cfg(stm32h7)]
     {
@@ -548,17 +530,6 @@ pub(crate) unsafe fn init(config: Config) {
         while !pac::SYSCFG.cccsr().read().ready() {}
     }
 
-    #[cfg(stm32h7)]
-    let rtc_clk = match config.rtc_mux {
-        Some(RtcClockSource::LSI) => Some(LSI_FREQ),
-        Some(RtcClockSource::LSE) => Some(match config.lse {
-            Some(Lse::Oscillator) => Hertz(32768),
-            Some(Lse::Bypass(freq)) => freq,
-            None => panic!("LSE not configured"),
-        }),
-        _ => None,
-    };
-
     set_freqs(Clocks {
         sys,
         ahb1: hclk,
@@ -573,10 +544,7 @@ pub(crate) unsafe fn init(config: Config) {
         apb1_tim,
         apb2_tim,
         adc,
-        #[cfg(stm32h7)]
-        rtc: rtc_clk,
-        #[cfg(stm32h7)]
-        rtc_hse: None,
+        rtc,
     });
 }
 
diff --git a/embassy-stm32/src/rcc/l0l1.rs b/embassy-stm32/src/rcc/l0l1.rs
index 4b1acae5d..d8a1fc10c 100644
--- a/embassy-stm32/src/rcc/l0l1.rs
+++ b/embassy-stm32/src/rcc/l0l1.rs
@@ -1,5 +1,3 @@
-use super::bd::BackupDomain;
-use super::RtcClockSource;
 pub use crate::pac::pwr::vals::Vos as VoltageScale;
 pub use crate::pac::rcc::vals::{
     Hpre as AHBPrescaler, Msirange as MSIRange, Plldiv as PLLDiv, Pllmul as PLLMul, Ppre as APBPrescaler,
@@ -14,9 +12,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// System clock mux source
 #[derive(Clone, Copy)]
 pub enum ClockSrc {
@@ -50,9 +45,7 @@ pub struct Config {
     pub apb2_pre: APBPrescaler,
     #[cfg(crs)]
     pub enable_hsi48: bool,
-    pub rtc: Option<RtcClockSource>,
-    pub lse: Option<Hertz>,
-    pub lsi: bool,
+    pub ls: super::LsConfig,
     pub voltage_scale: VoltageScale,
 }
 
@@ -66,10 +59,8 @@ impl Default for Config {
             apb2_pre: APBPrescaler::DIV1,
             #[cfg(crs)]
             enable_hsi48: false,
-            rtc: None,
-            lse: None,
-            lsi: false,
             voltage_scale: VoltageScale::RANGE1,
+            ls: Default::default(),
         }
     }
 }
@@ -144,11 +135,7 @@ pub(crate) unsafe fn init(config: Config) {
         }
     };
 
-    BackupDomain::configure_ls(
-        config.rtc.unwrap_or(RtcClockSource::NOCLOCK),
-        config.lsi,
-        config.lse.map(|_| Default::default()),
-    );
+    let rtc = config.ls.init();
 
     let wait_states = match (config.voltage_scale, sys_clk.0) {
         (VoltageScale::RANGE1, ..=16_000_000) => 0,
@@ -227,5 +214,6 @@ pub(crate) unsafe fn init(config: Config) {
         apb2: apb2_freq,
         apb1_tim: apb1_tim_freq,
         apb2_tim: apb2_tim_freq,
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/l4.rs b/embassy-stm32/src/rcc/l4.rs
index 686bbd4ee..1e5733d31 100644
--- a/embassy-stm32/src/rcc/l4.rs
+++ b/embassy-stm32/src/rcc/l4.rs
@@ -5,16 +5,12 @@ pub use crate::pac::rcc::vals::{
 };
 use crate::pac::rcc::vals::{Msirange, Pllsrc, Sw};
 use crate::pac::{FLASH, RCC};
-use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// System clock mux source
 #[derive(Clone, Copy)]
 pub enum ClockSrc {
@@ -51,9 +47,7 @@ pub struct Config {
     pub pllsai1: Option<(PllMul, PllPreDiv, Option<PllRDiv>, Option<PllQDiv>, Option<PllPDiv>)>,
     #[cfg(not(any(stm32l471, stm32l475, stm32l476, stm32l486)))]
     pub hsi48: bool,
-    pub rtc_mux: RtcClockSource,
-    pub lse: Option<Hertz>,
-    pub lsi: bool,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -67,9 +61,7 @@ impl Default for Config {
             pllsai1: None,
             #[cfg(not(any(stm32l471, stm32l475, stm32l476, stm32l486)))]
             hsi48: false,
-            rtc_mux: RtcClockSource::LSI,
-            lsi: true,
-            lse: None,
+            ls: Default::default(),
         }
     }
 }
@@ -95,7 +87,7 @@ pub(crate) unsafe fn init(config: Config) {
         while RCC.cfgr().read().sws() != Sw::MSI {}
     }
 
-    BackupDomain::configure_ls(config.rtc_mux, config.lsi, config.lse.map(|_| Default::default()));
+    let rtc = config.ls.init();
 
     let (sys_clk, sw) = match config.mux {
         ClockSrc::MSI(range) => {
@@ -105,12 +97,8 @@ pub(crate) unsafe fn init(config: Config) {
                 w.set_msirgsel(true);
                 w.set_msion(true);
 
-                if config.rtc_mux == RtcClockSource::LSE {
-                    // If LSE is enabled, enable calibration of MSI
-                    w.set_msipllen(true);
-                } else {
-                    w.set_msipllen(false);
-                }
+                // If LSE is enabled, enable calibration of MSI
+                w.set_msipllen(config.ls.lse.is_some());
             });
             while !RCC.cr().read().msirdy() {}
 
@@ -285,6 +273,7 @@ pub(crate) unsafe fn init(config: Config) {
         apb2: apb2_freq,
         apb1_tim: apb1_tim_freq,
         apb2_tim: apb2_tim_freq,
+        rtc,
     });
 }
 
diff --git a/embassy-stm32/src/rcc/l5.rs b/embassy-stm32/src/rcc/l5.rs
index ac4804d4f..1f4e00344 100644
--- a/embassy-stm32/src/rcc/l5.rs
+++ b/embassy-stm32/src/rcc/l5.rs
@@ -5,16 +5,12 @@ pub use crate::pac::rcc::vals::{
 };
 use crate::pac::rcc::vals::{Msirange, Pllsrc, Sw};
 use crate::pac::{FLASH, PWR, RCC};
-use crate::rcc::bd::RtcClockSource;
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// System clock mux source
 #[derive(Clone, Copy)]
 pub enum ClockSrc {
@@ -50,9 +46,7 @@ pub struct Config {
     pub apb2_pre: APBPrescaler,
     pub pllsai1: Option<(PllMul, PllPreDiv, Option<PllRDiv>, Option<PllQDiv>, Option<PllPDiv>)>,
     pub hsi48: bool,
-    pub rtc_mux: RtcClockSource,
-    pub lse: Option<Hertz>,
-    pub lsi: bool,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -65,9 +59,7 @@ impl Default for Config {
             apb2_pre: APBPrescaler::DIV1,
             pllsai1: None,
             hsi48: false,
-            rtc_mux: RtcClockSource::LSI,
-            lsi: true,
-            lse: None,
+            ls: Default::default(),
         }
     }
 }
@@ -93,7 +85,7 @@ pub(crate) unsafe fn init(config: Config) {
         while RCC.cfgr().read().sws() != Sw::MSI {}
     }
 
-    //BackupDomain::configure_ls(config.rtc_mux, config.lsi, config.lse.map(|_| Default::default()));
+    let rtc = config.ls.init();
 
     PWR.cr1().modify(|w| w.set_vos(stm32_metapac::pwr::vals::Vos::RANGE0));
     let (sys_clk, sw) = match config.mux {
@@ -104,12 +96,8 @@ pub(crate) unsafe fn init(config: Config) {
                 w.set_msirgsel(true);
                 w.set_msion(true);
 
-                if config.rtc_mux == RtcClockSource::LSE {
-                    // If LSE is enabled, enable calibration of MSI
-                    w.set_msipllen(true);
-                } else {
-                    w.set_msipllen(false);
-                }
+                // If LSE is enabled, enable calibration of MSI
+                w.set_msipllen(config.ls.lse.is_some());
             });
             while !RCC.cr().read().msirdy() {}
 
@@ -280,6 +268,7 @@ pub(crate) unsafe fn init(config: Config) {
         apb2: apb2_freq,
         apb1_tim: apb1_tim_freq,
         apb2_tim: apb2_tim_freq,
+        rtc,
     });
 }
 
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index 3d4de0e6e..a9e53d424 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -2,11 +2,11 @@
 
 use core::mem::MaybeUninit;
 
-pub use crate::rcc::bd::RtcClockSource;
 use crate::time::Hertz;
 
-pub(crate) mod bd;
+mod bd;
 mod mco;
+pub use bd::*;
 pub use mco::*;
 
 #[cfg_attr(rcc_f0, path = "f0.rs")]
@@ -132,13 +132,7 @@ pub struct Clocks {
     #[cfg(stm32f334)]
     pub hrtim: Option<Hertz>,
 
-    #[cfg(any(rcc_wb, rcc_f4, rcc_f410, rcc_f7, rcc_h7, rcc_h7rm0433, rcc_h7ab))]
-    /// Set only if the lsi or lse is configured, indicates stop is supported
     pub rtc: Option<Hertz>,
-
-    #[cfg(any(rcc_wb, rcc_f4, rcc_f410, rcc_h7, rcc_h7rm0433, rcc_h7ab))]
-    /// Set if the hse is configured, indicates stop is not supported
-    pub rtc_hse: Option<Hertz>,
 }
 
 #[cfg(feature = "low-power")]
@@ -166,14 +160,6 @@ pub(crate) fn clock_refcount_sub() {
 /// The existence of this value indicates that the clock configuration can no longer be changed
 static mut CLOCK_FREQS: MaybeUninit<Clocks> = MaybeUninit::uninit();
 
-#[cfg(stm32wb)]
-/// RCC initialization function
-pub(crate) unsafe fn init(config: Config) {
-    set_freqs(compute_clocks(&config));
-
-    configure_clocks(&config);
-}
-
 /// Sets the clock frequencies
 ///
 /// Safety: Sets a mutable global.
diff --git a/embassy-stm32/src/rcc/u5.rs b/embassy-stm32/src/rcc/u5.rs
index d8fb17301..68a8d3a35 100644
--- a/embassy-stm32/src/rcc/u5.rs
+++ b/embassy-stm32/src/rcc/u5.rs
@@ -7,9 +7,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 pub use crate::pac::pwr::vals::Vos as VoltageScale;
 
 #[derive(Copy, Clone)]
@@ -111,7 +108,6 @@ impl Into<Sw> for ClockSrc {
     }
 }
 
-#[derive(Copy, Clone)]
 pub struct Config {
     pub mux: ClockSrc,
     pub ahb_pre: AHBPrescaler,
@@ -125,6 +121,7 @@ pub struct Config {
     ///
     /// See RM0456 § 10.5.4 for a general overview and § 11.4.10 for clock source frequency limits.
     pub voltage_range: VoltageScale,
+    pub ls: super::LsConfig,
 }
 
 impl Config {
@@ -193,6 +190,7 @@ impl Default for Config {
             apb3_pre: APBPrescaler::DIV1,
             hsi48: false,
             voltage_range: VoltageScale::RANGE3,
+            ls: Default::default(),
         }
     }
 }
@@ -434,6 +432,8 @@ pub(crate) unsafe fn init(config: Config) {
         }
     };
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: sys_clk,
         ahb1: ahb_freq,
@@ -444,6 +444,7 @@ pub(crate) unsafe fn init(config: Config) {
         apb3: apb3_freq,
         apb1_tim: apb1_tim_freq,
         apb2_tim: apb2_tim_freq,
+        rtc,
     });
 }
 
diff --git a/embassy-stm32/src/rcc/wb.rs b/embassy-stm32/src/rcc/wb.rs
index f8eeaa953..181e6bb5b 100644
--- a/embassy-stm32/src/rcc/wb.rs
+++ b/embassy-stm32/src/rcc/wb.rs
@@ -2,16 +2,12 @@ pub use crate::pac::rcc::vals::{
     Hpre as AHBPrescaler, Hsepre as HsePrescaler, Pllm, Plln, Pllp, Pllq, Pllr, Pllsrc as PllSource,
     Ppre as APBPrescaler, Sw as Sysclk,
 };
-use crate::rcc::bd::{BackupDomain, RtcClockSource};
-use crate::rcc::Clocks;
-use crate::time::{khz, mhz, Hertz};
+use crate::rcc::{set_freqs, Clocks};
+use crate::time::{mhz, Hertz};
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 pub struct Hse {
     pub prediv: HsePrescaler,
 
@@ -42,11 +38,8 @@ pub struct Pll {
 /// Clocks configutation
 pub struct Config {
     pub hse: Option<Hse>,
-    pub lse: Option<Hertz>,
-    pub lsi: bool,
     pub sys: Sysclk,
     pub mux: Option<PllMux>,
-    pub rtc: Option<RtcClockSource>,
 
     pub pll: Option<Pll>,
     pub pllsai: Option<Pll>,
@@ -56,6 +49,8 @@ pub struct Config {
     pub ahb3_pre: AHBPrescaler,
     pub apb1_pre: APBPrescaler,
     pub apb2_pre: APBPrescaler,
+
+    pub ls: super::LsConfig,
 }
 
 pub const WPAN_DEFAULT: Config = Config {
@@ -63,14 +58,13 @@ pub const WPAN_DEFAULT: Config = Config {
         frequency: mhz(32),
         prediv: HsePrescaler::DIV1,
     }),
-    lse: Some(khz(32)),
     sys: Sysclk::PLL,
     mux: Some(PllMux {
         source: PllSource::HSE,
         prediv: Pllm::DIV2,
     }),
-    rtc: Some(RtcClockSource::LSE),
-    lsi: false,
+
+    ls: super::LsConfig::default_lse(),
 
     pll: Some(Pll {
         mul: Plln::MUL12,
@@ -92,13 +86,12 @@ impl Default for Config {
     fn default() -> Config {
         Config {
             hse: None,
-            lse: None,
             sys: Sysclk::HSI16,
             mux: None,
             pll: None,
             pllsai: None,
-            rtc: None,
-            lsi: false,
+
+            ls: Default::default(),
 
             ahb1_pre: AHBPrescaler::DIV1,
             ahb2_pre: AHBPrescaler::DIV1,
@@ -109,7 +102,9 @@ impl Default for Config {
     }
 }
 
-pub(crate) fn compute_clocks(config: &Config) -> Clocks {
+#[cfg(stm32wb)]
+/// RCC initialization function
+pub(crate) unsafe fn init(config: Config) {
     let hse_clk = config.hse.as_ref().map(|hse| hse.frequency / hse.prediv);
 
     let mux_clk = config.mux.as_ref().map(|pll_mux| {
@@ -160,27 +155,6 @@ pub(crate) fn compute_clocks(config: &Config) -> Clocks {
         }
     };
 
-    let rtc_clk = match config.rtc {
-        Some(RtcClockSource::LSI) => Some(LSI_FREQ),
-        Some(RtcClockSource::LSE) => Some(config.lse.unwrap()),
-        _ => None,
-    };
-
-    Clocks {
-        sys: sys_clk,
-        ahb1: ahb1_clk,
-        ahb2: ahb2_clk,
-        ahb3: ahb3_clk,
-        apb1: apb1_clk,
-        apb2: apb2_clk,
-        apb1_tim: apb1_tim_clk,
-        apb2_tim: apb2_tim_clk,
-        rtc: rtc_clk,
-        rtc_hse: None,
-    }
-}
-
-pub(crate) fn configure_clocks(config: &Config) {
     let rcc = crate::pac::RCC;
 
     let needs_hsi = if let Some(pll_mux) = &config.mux {
@@ -199,11 +173,7 @@ pub(crate) fn configure_clocks(config: &Config) {
 
     rcc.cfgr().modify(|w| w.set_stopwuck(true));
 
-    BackupDomain::configure_ls(
-        config.rtc.unwrap_or(RtcClockSource::NOCLOCK),
-        config.lsi,
-        config.lse.map(|_| Default::default()),
-    );
+    let rtc = config.ls.init();
 
     match &config.hse {
         Some(hse) => {
@@ -263,4 +233,16 @@ pub(crate) fn configure_clocks(config: &Config) {
         w.set_c2hpre(config.ahb2_pre);
         w.set_shdhpre(config.ahb3_pre);
     });
+
+    set_freqs(Clocks {
+        sys: sys_clk,
+        ahb1: ahb1_clk,
+        ahb2: ahb2_clk,
+        ahb3: ahb3_clk,
+        apb1: apb1_clk,
+        apb2: apb2_clk,
+        apb1_tim: apb1_tim_clk,
+        apb2_tim: apb2_tim_clk,
+        rtc,
+    })
 }
diff --git a/embassy-stm32/src/rcc/wba.rs b/embassy-stm32/src/rcc/wba.rs
index d79b3063e..ff5669ec5 100644
--- a/embassy-stm32/src/rcc/wba.rs
+++ b/embassy-stm32/src/rcc/wba.rs
@@ -7,9 +7,6 @@ use crate::time::Hertz;
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 pub use crate::pac::pwr::vals::Vos as VoltageScale;
 pub use crate::pac::rcc::vals::{Hpre as AHBPrescaler, Ppre as APBPrescaler};
 
@@ -43,13 +40,13 @@ impl Into<Sw> for ClockSrc {
     }
 }
 
-#[derive(Copy, Clone)]
 pub struct Config {
     pub mux: ClockSrc,
     pub ahb_pre: AHBPrescaler,
     pub apb1_pre: APBPrescaler,
     pub apb2_pre: APBPrescaler,
     pub apb7_pre: APBPrescaler,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -60,6 +57,7 @@ impl Default for Config {
             apb1_pre: APBPrescaler::DIV1,
             apb2_pre: APBPrescaler::DIV1,
             apb7_pre: APBPrescaler::DIV1,
+            ls: Default::default(),
         }
     }
 }
@@ -140,6 +138,8 @@ pub(crate) unsafe fn init(config: Config) {
         }
     };
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: sys_clk,
         ahb1: ahb_freq,
@@ -150,5 +150,6 @@ pub(crate) unsafe fn init(config: Config) {
         apb7: apb7_freq,
         apb1_tim: apb1_tim_freq,
         apb2_tim: apb2_tim_freq,
+        rtc,
     });
 }
diff --git a/embassy-stm32/src/rcc/wl.rs b/embassy-stm32/src/rcc/wl.rs
index 4c3fe5051..366ca1369 100644
--- a/embassy-stm32/src/rcc/wl.rs
+++ b/embassy-stm32/src/rcc/wl.rs
@@ -5,16 +5,12 @@ pub use crate::pac::rcc::vals::{
     Pllsrc as PllSource, Ppre as APBPrescaler,
 };
 use crate::pac::{FLASH, RCC};
-use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
 
 /// HSI speed
 pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 
-/// LSI speed
-pub const LSI_FREQ: Hertz = Hertz(32_000);
-
 /// HSE speed
 pub const HSE_FREQ: Hertz = Hertz(32_000_000);
 
@@ -33,10 +29,8 @@ pub struct Config {
     pub shd_ahb_pre: AHBPrescaler,
     pub apb1_pre: APBPrescaler,
     pub apb2_pre: APBPrescaler,
-    pub rtc_mux: RtcClockSource,
-    pub lse: Option<Hertz>,
-    pub lsi: bool,
     pub adc_clock_source: AdcClockSource,
+    pub ls: super::LsConfig,
 }
 
 impl Default for Config {
@@ -48,10 +42,8 @@ impl Default for Config {
             shd_ahb_pre: AHBPrescaler::DIV1,
             apb1_pre: APBPrescaler::DIV1,
             apb2_pre: APBPrescaler::DIV1,
-            rtc_mux: RtcClockSource::LSI,
-            lsi: true,
-            lse: None,
             adc_clock_source: AdcClockSource::HSI16,
+            ls: Default::default(),
         }
     }
 }
@@ -104,9 +96,6 @@ pub(crate) unsafe fn init(config: Config) {
 
     while FLASH.acr().read().latency() != ws {}
 
-    // Enables the LSI if configured
-    BackupDomain::configure_ls(config.rtc_mux, config.lsi, config.lse.map(|_| Default::default()));
-
     match config.mux {
         ClockSrc::HSI16 => {
             // Enable HSI16
@@ -129,12 +118,8 @@ pub(crate) unsafe fn init(config: Config) {
                 w.set_msirange(range);
                 w.set_msion(true);
 
-                if config.rtc_mux == RtcClockSource::LSE {
-                    // If LSE is enabled, enable calibration of MSI
-                    w.set_msipllen(true);
-                } else {
-                    w.set_msipllen(false);
-                }
+                // If LSE is enabled, enable calibration of MSI
+                w.set_msipllen(config.ls.lse.is_some());
             });
             while !RCC.cr().read().msirdy() {}
         }
@@ -156,6 +141,8 @@ pub(crate) unsafe fn init(config: Config) {
 
     // TODO: switch voltage range
 
+    let rtc = config.ls.init();
+
     set_freqs(Clocks {
         sys: sys_clk,
         ahb1: ahb_freq,
@@ -166,6 +153,7 @@ pub(crate) unsafe fn init(config: Config) {
         apb3: shd_ahb_freq,
         apb1_tim: apb1_tim_freq,
         apb2_tim: apb2_tim_freq,
+        rtc,
     });
 }
 
diff --git a/embassy-stm32/src/rtc/mod.rs b/embassy-stm32/src/rtc/mod.rs
index 28dde2eb1..cf34d2191 100644
--- a/embassy-stm32/src/rtc/mod.rs
+++ b/embassy-stm32/src/rtc/mod.rs
@@ -10,7 +10,6 @@ use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
 use embassy_sync::blocking_mutex::Mutex;
 
 pub use self::datetime::{DateTime, DayOfWeek, Error as DateTimeError};
-pub use crate::rcc::RtcClockSource;
 use crate::time::Hertz;
 
 /// refer to AN4759 to compare features of RTC2 and RTC3
@@ -184,7 +183,7 @@ impl Default for RtcCalibrationCyclePeriod {
 
 impl Rtc {
     pub fn new(_rtc: impl Peripheral<P = RTC>, rtc_config: RtcConfig) -> Self {
-        #[cfg(any(rcc_wle, rcc_wl5, rcc_g4, rcc_g0, rtc_v2l4, rtc_v2wb))]
+        #[cfg(not(any(stm32l0, stm32f3, stm32l1, stm32f0, stm32f2)))]
         <RTC as crate::rcc::sealed::RccPeripheral>::enable();
 
         let mut this = Self {
@@ -204,19 +203,8 @@ impl Rtc {
     }
 
     fn frequency() -> Hertz {
-        #[cfg(any(rcc_wb, rcc_f4, rcc_f410, rcc_h5, rcc_h50, rcc_h7, rcc_h7rm0433, rcc_h7ab))]
         let freqs = unsafe { crate::rcc::get_freqs() };
-
-        // Load the clock frequency from the rcc mod, if supported
-        #[cfg(any(rcc_wb, rcc_f4, rcc_f410, rcc_h5, rcc_h50, rcc_h7, rcc_h7rm0433, rcc_h7ab))]
-        match freqs.rtc {
-            Some(hertz) => hertz,
-            None => freqs.rtc_hse.unwrap(),
-        }
-
-        // Assume the  default value, if not supported
-        #[cfg(not(any(rcc_wb, rcc_f4, rcc_f410, rcc_h5, rcc_h50, rcc_h7, rcc_h7rm0433, rcc_h7ab)))]
-        Hertz(32_768)
+        freqs.rtc.unwrap()
     }
 
     /// Acquire a [`RtcTimeProvider`] instance.
diff --git a/examples/stm32f4/src/bin/rtc.rs b/examples/stm32f4/src/bin/rtc.rs
index e33746008..e95ad5779 100644
--- a/examples/stm32f4/src/bin/rtc.rs
+++ b/examples/stm32f4/src/bin/rtc.rs
@@ -5,16 +5,14 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::rtc::{Rtc, RtcClockSource, RtcConfig};
+use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_stm32::Config;
 use embassy_time::{Duration, Timer};
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
-    let mut config = Config::default();
-    config.rcc.lsi = true;
-    config.rcc.rtc = Option::Some(RtcClockSource::LSI);
+    let config = Config::default();
     let p = embassy_stm32::init(config);
 
     info!("Hello World!");
diff --git a/examples/stm32h7/src/bin/rtc.rs b/examples/stm32h7/src/bin/rtc.rs
index eeb94073b..f2a19af81 100644
--- a/examples/stm32h7/src/bin/rtc.rs
+++ b/examples/stm32h7/src/bin/rtc.rs
@@ -5,20 +5,18 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::rcc::Lse;
-use embassy_stm32::rtc::{Rtc, RtcClockSource, RtcConfig};
+use embassy_stm32::rcc::LsConfig;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_stm32::Config;
 use embassy_time::{Duration, Timer};
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
-    let p = {
-        let mut config = Config::default();
-        config.rcc.lse = Some(Lse::Oscillator);
-        config.rcc.rtc_mux = Some(RtcClockSource::LSE);
-        embassy_stm32::init(config)
-    };
+    let mut config = Config::default();
+    config.rcc.ls = LsConfig::default_lse();
+
+    let p = embassy_stm32::init(config);
     info!("Hello World!");
 
     let now = NaiveDate::from_ymd_opt(2020, 5, 15)
diff --git a/examples/stm32l4/src/bin/rtc.rs b/examples/stm32l4/src/bin/rtc.rs
index 7e2b8c783..33efc76b3 100644
--- a/examples/stm32l4/src/bin/rtc.rs
+++ b/examples/stm32l4/src/bin/rtc.rs
@@ -5,7 +5,7 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::rcc::{self, ClockSrc, PLLSource, PllMul, PllPreDiv, PllRDiv};
+use embassy_stm32::rcc::{ClockSrc, LsConfig, PLLSource, PllMul, PllPreDiv, PllRDiv};
 use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_stm32::time::Hertz;
 use embassy_stm32::Config;
@@ -23,8 +23,7 @@ async fn main(_spawner: Spawner) {
             PllMul::MUL20,
             None,
         );
-        config.rcc.lse = Some(Hertz(32_768));
-        config.rcc.rtc_mux = rcc::RtcClockSource::LSE;
+        config.rcc.ls = LsConfig::default_lse();
         embassy_stm32::init(config)
     };
     info!("Hello World!");
diff --git a/examples/stm32l4/src/bin/spe_adin1110_http_server.rs b/examples/stm32l4/src/bin/spe_adin1110_http_server.rs
index 8db89be24..7193d1f1f 100644
--- a/examples/stm32l4/src/bin/spe_adin1110_http_server.rs
+++ b/examples/stm32l4/src/bin/spe_adin1110_http_server.rs
@@ -32,7 +32,6 @@ use embedded_io::Write as bWrite;
 use embedded_io_async::Write;
 use hal::gpio::{Input, Level, Output, Speed};
 use hal::i2c::{self, I2c};
-use hal::rcc::{self};
 use hal::rng::{self, Rng};
 use hal::{bind_interrupts, exti, pac, peripherals};
 use heapless::Vec;
@@ -86,7 +85,6 @@ async fn main(spawner: Spawner) {
         None,
     );
     config.rcc.hsi48 = true; // needed for rng
-    config.rcc.rtc_mux = rcc::RtcClockSource::LSI;
 
     let dp = embassy_stm32::init(config);
 
diff --git a/examples/stm32wl/src/bin/lora_lorawan.rs b/examples/stm32wl/src/bin/lora_lorawan.rs
index 6546a4bfa..8c789afbc 100644
--- a/examples/stm32wl/src/bin/lora_lorawan.rs
+++ b/examples/stm32wl/src/bin/lora_lorawan.rs
@@ -34,7 +34,6 @@ bind_interrupts!(struct Irqs{
 async fn main(_spawner: Spawner) {
     let mut config = embassy_stm32::Config::default();
     config.rcc.mux = embassy_stm32::rcc::ClockSrc::HSE;
-    config.rcc.rtc_mux = embassy_stm32::rcc::RtcClockSource::LSI;
     let p = embassy_stm32::init(config);
 
     pac::RCC.ccipr().modify(|w| w.set_rngsel(0b01));
diff --git a/examples/stm32wl/src/bin/random.rs b/examples/stm32wl/src/bin/random.rs
index d5b819700..7c7e8a4e6 100644
--- a/examples/stm32wl/src/bin/random.rs
+++ b/examples/stm32wl/src/bin/random.rs
@@ -16,7 +16,6 @@ bind_interrupts!(struct Irqs{
 async fn main(_spawner: Spawner) {
     let mut config = embassy_stm32::Config::default();
     config.rcc.mux = embassy_stm32::rcc::ClockSrc::HSE;
-    config.rcc.rtc_mux = embassy_stm32::rcc::RtcClockSource::LSI;
 
     let p = embassy_stm32::init(config);
     pac::RCC.ccipr().modify(|w| {
diff --git a/examples/stm32wl/src/bin/rtc.rs b/examples/stm32wl/src/bin/rtc.rs
index b26ddc2f5..a6bb28013 100644
--- a/examples/stm32wl/src/bin/rtc.rs
+++ b/examples/stm32wl/src/bin/rtc.rs
@@ -5,9 +5,8 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::rcc::ClockSrc;
-use embassy_stm32::rtc::{Rtc, RtcClockSource, RtcConfig};
-use embassy_stm32::time::Hertz;
+use embassy_stm32::rcc::{ClockSrc, LsConfig};
+use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_stm32::Config;
 use embassy_time::{Duration, Timer};
 use {defmt_rtt as _, panic_probe as _};
@@ -17,8 +16,7 @@ async fn main(_spawner: Spawner) {
     let p = {
         let mut config = Config::default();
         config.rcc.mux = ClockSrc::HSE;
-        config.rcc.lse = Some(Hertz(32_768));
-        config.rcc.rtc_mux = RtcClockSource::LSE;
+        config.rcc.ls = LsConfig::default_lse();
         embassy_stm32::init(config)
     };
     info!("Hello World!");
diff --git a/tests/stm32/Cargo.toml b/tests/stm32/Cargo.toml
index ef835eed8..a1481c7c2 100644
--- a/tests/stm32/Cargo.toml
+++ b/tests/stm32/Cargo.toml
@@ -10,19 +10,19 @@ stm32f103c8 = ["embassy-stm32/stm32f103c8", "not-gpdma"]     # Blue Pill
 stm32f429zi = ["embassy-stm32/stm32f429zi", "chrono", "eth", "stop", "can", "not-gpdma", "dac-adc-pin"]     # Nucleo "sdmmc"
 stm32g071rb = ["embassy-stm32/stm32g071rb", "not-gpdma", "dac-adc-pin"]     # Nucleo
 stm32c031c6 = ["embassy-stm32/stm32c031c6", "not-gpdma"]     # Nucleo
-stm32g491re = ["embassy-stm32/stm32g491re", "not-gpdma"]     # Nucleo
+stm32g491re = ["embassy-stm32/stm32g491re", "chrono", "not-gpdma"]     # Nucleo
 stm32h755zi = ["embassy-stm32/stm32h755zi-cm7", "chrono", "not-gpdma", "eth", "dac-adc-pin"] # Nucleo
-stm32wb55rg = ["embassy-stm32/stm32wb55rg", "not-gpdma", "ble", "mac" ]     # Nucleo
-stm32h563zi = ["embassy-stm32/stm32h563zi", "eth"]     # Nucleo
-stm32u585ai = ["embassy-stm32/stm32u585ai"]     # IoT board
+stm32wb55rg = ["embassy-stm32/stm32wb55rg", "chrono", "not-gpdma", "ble", "mac" ]     # Nucleo
+stm32h563zi = ["embassy-stm32/stm32h563zi", "chrono", "eth"]     # Nucleo
+stm32u585ai = ["embassy-stm32/stm32u585ai", "chrono"]     # IoT board
 stm32l073rz = ["embassy-stm32/stm32l073rz", "not-gpdma"]     # Nucleo
-stm32l152re = ["embassy-stm32/stm32l152re", "not-gpdma"]     # Nucleo
-stm32l4a6zg = ["embassy-stm32/stm32l4a6zg", "not-gpdma"]     # Nucleo
-stm32l4r5zi = ["embassy-stm32/stm32l4r5zi", "not-gpdma"]     # Nucleo
+stm32l152re = ["embassy-stm32/stm32l152re", "chrono", "not-gpdma"]     # Nucleo
+stm32l4a6zg = ["embassy-stm32/stm32l4a6zg", "chrono", "not-gpdma"]     # Nucleo
+stm32l4r5zi = ["embassy-stm32/stm32l4r5zi", "chrono", "not-gpdma"]     # Nucleo
 stm32l552ze = ["embassy-stm32/stm32l552ze", "not-gpdma"]     # Nucleo
-stm32f767zi = ["embassy-stm32/stm32f767zi", "not-gpdma", "eth"]     # Nucleo
-stm32f207zg = ["embassy-stm32/stm32f207zg", "not-gpdma", "eth"]     # Nucleo
-stm32f303ze = ["embassy-stm32/stm32f303ze", "not-gpdma"]     # Nucleo
+stm32f767zi = ["embassy-stm32/stm32f767zi", "chrono", "not-gpdma", "eth"]     # Nucleo
+stm32f207zg = ["embassy-stm32/stm32f207zg", "chrono", "not-gpdma", "eth"]     # Nucleo
+stm32f303ze = ["embassy-stm32/stm32f303ze", "chrono", "not-gpdma"]     # Nucleo
 stm32l496zg = ["embassy-stm32/stm32l496zg", "not-gpdma"]     # Nucleo
 
 eth = []
diff --git a/tests/stm32/src/bin/rtc.rs b/tests/stm32/src/bin/rtc.rs
index 1f0d630c9..46fdbfaeb 100644
--- a/tests/stm32/src/bin/rtc.rs
+++ b/tests/stm32/src/bin/rtc.rs
@@ -10,26 +10,14 @@ use chrono::{NaiveDate, NaiveDateTime};
 use common::*;
 use defmt::assert;
 use embassy_executor::Spawner;
-use embassy_stm32::rcc::RtcClockSource;
+use embassy_stm32::rcc::LsConfig;
 use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_time::{Duration, Timer};
 
 #[embassy_executor::main]
 async fn main(_spawner: Spawner) {
     let mut config = config();
-
-    #[cfg(feature = "stm32h755zi")]
-    {
-        use embassy_stm32::rcc::Lse;
-        config.rcc.lse = Some(Lse::Oscillator);
-        config.rcc.rtc_mux = Some(RtcClockSource::LSE);
-    }
-    #[cfg(not(feature = "stm32h755zi"))]
-    {
-        use embassy_stm32::time::Hertz;
-        config.rcc.lse = Some(Hertz(32_768));
-        config.rcc.rtc = Some(RtcClockSource::LSE);
-    }
+    config.rcc.ls = LsConfig::default_lse();
 
     let p = embassy_stm32::init(config);
     info!("Hello World!");
diff --git a/tests/stm32/src/bin/stop.rs b/tests/stm32/src/bin/stop.rs
index 55c4aa900..929869bc9 100644
--- a/tests/stm32/src/bin/stop.rs
+++ b/tests/stm32/src/bin/stop.rs
@@ -11,9 +11,8 @@ use common::*;
 use cortex_m_rt::entry;
 use embassy_executor::Spawner;
 use embassy_stm32::low_power::{stop_with_rtc, Executor};
-use embassy_stm32::rcc::RtcClockSource;
+use embassy_stm32::rcc::LsConfig;
 use embassy_stm32::rtc::{Rtc, RtcConfig};
-use embassy_stm32::time::Hertz;
 use embassy_stm32::Config;
 use embassy_time::{Duration, Timer};
 use static_cell::make_static;
@@ -49,9 +48,7 @@ async fn async_main(spawner: Spawner) {
     let _ = config();
 
     let mut config = Config::default();
-
-    config.rcc.lse = Some(Hertz(32_768));
-    config.rcc.rtc = Some(RtcClockSource::LSE);
+    config.rcc.ls = LsConfig::default_lse();
 
     let p = embassy_stm32::init(config);
     info!("Hello World!");