Merge pull request #1830 from xoviat/rtc

stm32: move backup domain in rcc mod

29 files changed, 224 insertions, 223 deletions

diff --git a/embassy-stm32/Cargo.toml b/embassy-stm32/Cargo.toml
index 150014afe..d0ada97a3 100644
--- a/embassy-stm32/Cargo.toml
+++ b/embassy-stm32/Cargo.toml
@@ -58,7 +58,7 @@ 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-2b87e34c661e19ff6dc603fabfe7fe99ab7261f7" }
+stm32-metapac = { git = "https://github.com/embassy-rs/stm32-data-generated", tag = "stm32-data-9a61a1f090462df8bd1751f89951f04934fdceb3" }
 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-2b87e34c661e19ff6dc603fabfe7fe99ab7261f7", default-features = false, features = ["metadata"]}
+stm32-metapac = { git = "https://github.com/embassy-rs/stm32-data-generated", tag = "stm32-data-9a61a1f090462df8bd1751f89951f04934fdceb3", default-features = false, features = ["metadata"]}
 
 [features]
 default = ["rt"]
diff --git a/embassy-stm32/src/rcc/bd.rs b/embassy-stm32/src/rcc/bd.rs
new file mode 100644
index 000000000..0fc116ed8
--- /dev/null
+++ b/embassy-stm32/src/rcc/bd.rs
@@ -0,0 +1,151 @@
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[repr(u8)]
+#[allow(dead_code)]
+pub enum RtcClockSource {
+    /// 00: No clock
+    NoClock = 0b00,
+    /// 01: LSE oscillator clock used as RTC clock
+    LSE = 0b01,
+    /// 10: LSI oscillator clock used as RTC clock
+    LSI = 0b10,
+    /// 11: HSE oscillator clock divided by 32 used as RTC clock
+    HSE = 0b11,
+}
+
+#[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;
+
+#[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))]
+        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_v2l0, rtc_v3u5)))]
+        {
+            cr.modify(|w| w.set_dbp(true));
+            while !cr.read().dbp() {}
+        }
+
+        #[cfg(any(rtc_v2l0, rtc_v2l1))]
+        let cr = crate::pac::RCC.csr();
+
+        #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
+        let cr = crate::pac::RCC.bdcr();
+
+        cr.modify(|w| f(w))
+    }
+
+    #[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();
+
+        #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
+        let r = crate::pac::RCC.bdcr().read();
+
+        r
+    }
+
+    #[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 set_rtc_clock_source(clock_source: RtcClockSource) {
+        let clock_source = clock_source as u8;
+        #[cfg(any(
+            all(not(any(rtc_v3, rtc_v3u5)), not(rtc_v2wb)),
+            all(any(rtc_v3, rtc_v3u5), not(any(rcc_wl5, rcc_wle)))
+        ))]
+        let clock_source = crate::pac::rcc::vals::Rtcsel::from_bits(clock_source);
+
+        #[cfg(not(rtc_v2wb))]
+        Self::modify(|w| {
+            // Select RTC source
+            w.set_rtcsel(clock_source);
+        });
+    }
+
+    #[cfg(any(
+        rtc_v2f0, rtc_v2f2, rtc_v2f3, rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l0, rtc_v2l1, rtc_v2l4, rtc_v2wb
+    ))]
+    #[allow(dead_code)]
+    pub fn enable_rtc() {
+        let reg = Self::read();
+
+        #[cfg(any(rtc_v2h7, rtc_v2l4, rtc_v2wb))]
+        assert!(!reg.lsecsson(), "RTC is not compatible with LSE CSS, yet.");
+
+        if !reg.rtcen() {
+            #[cfg(not(any(rtc_v2l0, rtc_v2l1, rtc_v2f2)))]
+            Self::modify(|w| w.set_bdrst(true));
+
+            Self::modify(|w| {
+                // Reset
+                #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
+                w.set_bdrst(false);
+
+                w.set_rtcen(true);
+                w.set_rtcsel(reg.rtcsel());
+
+                // Restore bcdr
+                #[cfg(any(rtc_v2l4, rtc_v2wb))]
+                w.set_lscosel(reg.lscosel());
+                #[cfg(any(rtc_v2l4, rtc_v2wb))]
+                w.set_lscoen(reg.lscoen());
+
+                w.set_lseon(reg.lseon());
+
+                #[cfg(any(rtc_v2f0, rtc_v2f7, rtc_v2h7, rtc_v2l4, rtc_v2wb))]
+                w.set_lsedrv(reg.lsedrv());
+                w.set_lsebyp(reg.lsebyp());
+            });
+        }
+    }
+
+    #[cfg(any(rtc_v3, rtc_v3u5))]
+    #[allow(dead_code)]
+    pub fn enable_rtc() {
+        let reg = Self::read();
+        assert!(!reg.lsecsson(), "RTC is not compatible with LSE CSS, yet.");
+
+        if !reg.rtcen() {
+            Self::modify(|w| w.set_bdrst(true));
+
+            Self::modify(|w| {
+                w.set_bdrst(false);
+
+                w.set_rtcen(true);
+                w.set_rtcsel(reg.rtcsel());
+
+                // Restore bcdr
+                w.set_lscosel(reg.lscosel());
+                w.set_lscoen(reg.lscoen());
+
+                w.set_lseon(reg.lseon());
+                w.set_lsedrv(reg.lsedrv());
+                w.set_lsebyp(reg.lsebyp());
+            });
+        }
+    }
+}
diff --git a/embassy-stm32/src/rcc/common.rs b/embassy-stm32/src/rcc/bus.rs
index 62736a43a..62736a43a 100644
--- a/embassy-stm32/src/rcc/common.rs
+++ b/embassy-stm32/src/rcc/bus.rs
diff --git a/embassy-stm32/src/rcc/c0.rs b/embassy-stm32/src/rcc/c0.rs
index 6a9326347..d85790797 100644
--- a/embassy-stm32/src/rcc/c0.rs
+++ b/embassy-stm32/src/rcc/c0.rs
@@ -1,4 +1,4 @@
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::flash::vals::Latency;
 use crate::pac::rcc::vals::{Hsidiv, Ppre, Sw};
 use crate::pac::{FLASH, RCC};
diff --git a/embassy-stm32/src/rcc/f2.rs b/embassy-stm32/src/rcc/f2.rs
index ec4ed99b8..9d9bc59fd 100644
--- a/embassy-stm32/src/rcc/f2.rs
+++ b/embassy-stm32/src/rcc/f2.rs
@@ -1,7 +1,7 @@
 use core::convert::TryFrom;
 use core::ops::{Div, Mul};
 
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::flash::vals::Latency;
 use crate::pac::rcc::vals::{Pllp, Pllsrc, Sw};
 use crate::pac::{FLASH, RCC};
@@ -201,7 +201,7 @@ pub struct PLLClocks {
     pub pll48_freq: Hertz,
 }
 
-pub use super::common::VoltageScale;
+pub use super::bus::VoltageScale;
 
 impl VoltageScale {
     const fn wait_states(&self, ahb_freq: Hertz) -> Option<Latency> {
diff --git a/embassy-stm32/src/rcc/f3.rs b/embassy-stm32/src/rcc/f3.rs
index 321270a70..7480c0393 100644
--- a/embassy-stm32/src/rcc/f3.rs
+++ b/embassy-stm32/src/rcc/f3.rs
@@ -201,9 +201,9 @@ fn calc_pll(config: &Config, Hertz(sysclk): Hertz) -> (Hertz, PllConfig) {
     // Calculates the Multiplier and the Divisor to arrive at
     // the required System clock from PLL source frequency
     let get_mul_div = |sysclk, pllsrcclk| {
-        let common_div = gcd(sysclk, pllsrcclk);
-        let mut multiplier = sysclk / common_div;
-        let mut divisor = pllsrcclk / common_div;
+        let bus_div = gcd(sysclk, pllsrcclk);
+        let mut multiplier = sysclk / bus_div;
+        let mut divisor = pllsrcclk / bus_div;
         // Minimum PLL multiplier is two
         if multiplier == 1 {
             multiplier *= 2;
diff --git a/embassy-stm32/src/rcc/f4.rs b/embassy-stm32/src/rcc/f4.rs
index ee9cb2897..10d3322aa 100644
--- a/embassy-stm32/src/rcc/f4.rs
+++ b/embassy-stm32/src/rcc/f4.rs
@@ -8,8 +8,8 @@ use crate::gpio::sealed::AFType;
 use crate::gpio::Speed;
 use crate::pac::rcc::vals::{Hpre, Ppre, Sw};
 use crate::pac::{FLASH, PWR, RCC};
+use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
-use crate::rtc::{Rtc, RtcClockSource};
 use crate::time::Hertz;
 use crate::{peripherals, Peripheral};
 
@@ -470,7 +470,7 @@ pub(crate) unsafe fn init(config: Config) {
     }
 
     config.rtc.map(|clock_source| {
-        Rtc::set_clock_source(clock_source);
+        BackupDomain::set_rtc_clock_source(clock_source);
     });
 
     let rtc = match config.rtc {
diff --git a/embassy-stm32/src/rcc/g0.rs b/embassy-stm32/src/rcc/g0.rs
index bf2d5199e..7fdbcb00c 100644
--- a/embassy-stm32/src/rcc/g0.rs
+++ b/embassy-stm32/src/rcc/g0.rs
@@ -1,4 +1,4 @@
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::flash::vals::Latency;
 use crate::pac::rcc::vals::{self, Hsidiv, Ppre, Sw};
 use crate::pac::{FLASH, PWR, RCC};
diff --git a/embassy-stm32/src/rcc/g4.rs b/embassy-stm32/src/rcc/g4.rs
index dff04023e..3b044cd11 100644
--- a/embassy-stm32/src/rcc/g4.rs
+++ b/embassy-stm32/src/rcc/g4.rs
@@ -2,7 +2,7 @@ use stm32_metapac::flash::vals::Latency;
 use stm32_metapac::rcc::vals::{Hpre, Pllsrc, Ppre, Sw};
 use stm32_metapac::FLASH;
 
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::{PWR, RCC};
 use crate::rcc::sealed::RccPeripheral;
 use crate::rcc::{set_freqs, Clocks};
diff --git a/embassy-stm32/src/rcc/h5.rs b/embassy-stm32/src/rcc/h5.rs
index 2e72b1931..5741cdf92 100644
--- a/embassy-stm32/src/rcc/h5.rs
+++ b/embassy-stm32/src/rcc/h5.rs
@@ -26,7 +26,7 @@ const VCO_MAX: u32 = 420_000_000;
 const VCO_WIDE_MIN: u32 = 128_000_000;
 const VCO_WIDE_MAX: u32 = 560_000_000;
 
-pub use super::common::{AHBPrescaler, APBPrescaler, VoltageScale};
+pub use super::bus::{AHBPrescaler, APBPrescaler, VoltageScale};
 
 pub enum HseMode {
     /// crystal/ceramic oscillator (HSEBYP=0)
diff --git a/embassy-stm32/src/rcc/h7.rs b/embassy-stm32/src/rcc/h7.rs
index 7fb4fb95b..a6e694618 100644
--- a/embassy-stm32/src/rcc/h7.rs
+++ b/embassy-stm32/src/rcc/h7.rs
@@ -24,7 +24,7 @@ pub const HSI48_FREQ: Hertz = Hertz(48_000_000);
 /// LSI speed
 pub const LSI_FREQ: Hertz = Hertz(32_000);
 
-pub use super::common::VoltageScale;
+pub use super::bus::VoltageScale;
 
 #[derive(Clone, Copy)]
 pub enum AdcClockSource {
diff --git a/embassy-stm32/src/rcc/l0.rs b/embassy-stm32/src/rcc/l0.rs
index 46b58ca7c..7f9ab01f1 100644
--- a/embassy-stm32/src/rcc/l0.rs
+++ b/embassy-stm32/src/rcc/l0.rs
@@ -1,4 +1,4 @@
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::rcc::vals::{Hpre, Msirange, Plldiv, Pllmul, Pllsrc, Ppre, Sw};
 use crate::pac::RCC;
 #[cfg(crs)]
diff --git a/embassy-stm32/src/rcc/l1.rs b/embassy-stm32/src/rcc/l1.rs
index bdfc5b87a..ed949ea6f 100644
--- a/embassy-stm32/src/rcc/l1.rs
+++ b/embassy-stm32/src/rcc/l1.rs
@@ -1,4 +1,4 @@
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::rcc::vals::{Hpre, Msirange, Plldiv, Pllmul, Pllsrc, Ppre, Sw};
 use crate::pac::{FLASH, RCC};
 use crate::rcc::{set_freqs, Clocks};
diff --git a/embassy-stm32/src/rcc/l4.rs b/embassy-stm32/src/rcc/l4.rs
index b34b8caab..c6bccfd26 100644
--- a/embassy-stm32/src/rcc/l4.rs
+++ b/embassy-stm32/src/rcc/l4.rs
@@ -4,13 +4,13 @@ use embassy_hal_internal::into_ref;
 use stm32_metapac::rcc::regs::Cfgr;
 use stm32_metapac::rcc::vals::{Lsedrv, Mcopre, Mcosel};
 
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::gpio::sealed::AFType;
 use crate::gpio::Speed;
 use crate::pac::rcc::vals::{Hpre, Msirange, Pllsrc, Ppre, Sw};
 use crate::pac::{FLASH, PWR, RCC};
+use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
-use crate::rtc::{Rtc, RtcClockSource as RCS};
 use crate::time::Hertz;
 use crate::{peripherals, Peripheral};
 
@@ -254,16 +254,11 @@ impl Default for Config {
             pllsai1: None,
             #[cfg(not(any(stm32l471, stm32l475, stm32l476, stm32l486)))]
             hsi48: false,
-            rtc_mux: RtcClockSource::LSI32,
+            rtc_mux: RtcClockSource::LSI,
         }
     }
 }
 
-pub enum RtcClockSource {
-    LSE32,
-    LSI32,
-}
-
 pub enum McoClock {
     DIV1,
     DIV2,
@@ -413,7 +408,7 @@ pub(crate) unsafe fn init(config: Config) {
     RCC.apb1enr1().modify(|w| w.set_pwren(true));
 
     match config.rtc_mux {
-        RtcClockSource::LSE32 => {
+        RtcClockSource::LSE => {
             // 1. Unlock the backup domain
             PWR.cr1().modify(|w| w.set_dbp(true));
 
@@ -429,17 +424,18 @@ pub(crate) unsafe fn init(config: Config) {
             // Wait until LSE is running
             while !RCC.bdcr().read().lserdy() {}
 
-            Rtc::set_clock_source(RCS::LSE);
+            BackupDomain::set_rtc_clock_source(RtcClockSource::LSE);
         }
-        RtcClockSource::LSI32 => {
+        RtcClockSource::LSI => {
             // Turn on the internal 32 kHz LSI oscillator
             RCC.csr().modify(|w| w.set_lsion(true));
 
             // Wait until LSI is running
             while !RCC.csr().read().lsirdy() {}
 
-            Rtc::set_clock_source(RCS::LSI);
+            BackupDomain::set_rtc_clock_source(RtcClockSource::LSI);
         }
+        _ => unreachable!(),
     }
 
     let (sys_clk, sw) = match config.mux {
@@ -451,7 +447,7 @@ pub(crate) unsafe fn init(config: Config) {
                 w.set_msirgsel(true);
                 w.set_msion(true);
 
-                if let RtcClockSource::LSE32 = config.rtc_mux {
+                if let RtcClockSource::LSE = config.rtc_mux {
                     // If LSE is enabled, enable calibration of MSI
                     w.set_msipllen(true);
                 } else {
diff --git a/embassy-stm32/src/rcc/l5.rs b/embassy-stm32/src/rcc/l5.rs
index a85e14889..9e4e0fc75 100644
--- a/embassy-stm32/src/rcc/l5.rs
+++ b/embassy-stm32/src/rcc/l5.rs
@@ -1,6 +1,6 @@
 use stm32_metapac::PWR;
 
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::rcc::vals::{Hpre, Msirange, Pllsrc, Ppre, Sw};
 use crate::pac::{FLASH, RCC};
 use crate::rcc::{set_freqs, Clocks};
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index 45a4d880d..9f1b3b663 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -1,9 +1,10 @@
 #![macro_use]
 
-pub mod common;
-
+pub(crate) mod bd;
+pub mod bus;
 use core::mem::MaybeUninit;
 
+pub use crate::rcc::bd::RtcClockSource;
 use crate::time::Hertz;
 
 #[cfg_attr(rcc_f0, path = "f0.rs")]
diff --git a/embassy-stm32/src/rcc/u5.rs b/embassy-stm32/src/rcc/u5.rs
index b5feeb0c4..4aca9cd3d 100644
--- a/embassy-stm32/src/rcc/u5.rs
+++ b/embassy-stm32/src/rcc/u5.rs
@@ -1,6 +1,6 @@
 use stm32_metapac::rcc::vals::{Msirange, Msirgsel, Pllm, Pllsrc, Sw};
 
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
 use crate::pac::{FLASH, RCC};
 use crate::rcc::{set_freqs, Clocks};
 use crate::time::Hertz;
@@ -11,7 +11,7 @@ pub const HSI_FREQ: Hertz = Hertz(16_000_000);
 /// LSI speed
 pub const LSI_FREQ: Hertz = Hertz(32_000);
 
-pub use super::common::VoltageScale;
+pub use super::bus::VoltageScale;
 
 #[derive(Copy, Clone)]
 pub enum ClockSrc {
diff --git a/embassy-stm32/src/rcc/wb.rs b/embassy-stm32/src/rcc/wb.rs
index ae708b37f..6a3eab707 100644
--- a/embassy-stm32/src/rcc/wb.rs
+++ b/embassy-stm32/src/rcc/wb.rs
@@ -1,6 +1,6 @@
-pub use super::common::{AHBPrescaler, APBPrescaler};
+pub use super::bus::{AHBPrescaler, APBPrescaler};
+use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::Clocks;
-use crate::rtc::{Rtc, RtcClockSource};
 use crate::time::{khz, mhz, Hertz};
 
 /// Most of clock setup is copied from stm32l0xx-hal, and adopted to the generated PAC,
@@ -375,5 +375,7 @@ pub(crate) fn configure_clocks(config: &Config) {
         w.set_shdhpre(config.ahb3_pre.into());
     });
 
-    config.rtc.map(|clock_source| Rtc::set_clock_source(clock_source));
+    config
+        .rtc
+        .map(|clock_source| BackupDomain::set_rtc_clock_source(clock_source));
 }
diff --git a/embassy-stm32/src/rcc/wl.rs b/embassy-stm32/src/rcc/wl.rs
index f1dd2bd7e..e33690d10 100644
--- a/embassy-stm32/src/rcc/wl.rs
+++ b/embassy-stm32/src/rcc/wl.rs
@@ -1,8 +1,7 @@
-pub use super::common::{AHBPrescaler, APBPrescaler, VoltageScale};
-use crate::pac::pwr::vals::Dbp;
+pub use super::bus::{AHBPrescaler, APBPrescaler, VoltageScale};
 use crate::pac::{FLASH, PWR, RCC};
+use crate::rcc::bd::{BackupDomain, RtcClockSource};
 use crate::rcc::{set_freqs, Clocks};
-use crate::rtc::{Rtc, RtcClockSource as RCS};
 use crate::time::Hertz;
 
 /// Most of clock setup is copied from stm32l0xx-hal, and adopted to the generated PAC,
@@ -130,16 +129,11 @@ impl Default for Config {
             apb2_pre: APBPrescaler::NotDivided,
             enable_lsi: false,
             enable_rtc_apb: false,
-            rtc_mux: RtcClockSource::LSI32,
+            rtc_mux: RtcClockSource::LSI,
         }
     }
 }
 
-pub enum RtcClockSource {
-    LSE32,
-    LSI32,
-}
-
 #[repr(u8)]
 pub enum Lsedrv {
     Low = 0,
@@ -215,9 +209,9 @@ pub(crate) unsafe fn init(config: Config) {
     while FLASH.acr().read().latency() != ws {}
 
     match config.rtc_mux {
-        RtcClockSource::LSE32 => {
+        RtcClockSource::LSE => {
             // 1. Unlock the backup domain
-            PWR.cr1().modify(|w| w.set_dbp(Dbp::ENABLED));
+            PWR.cr1().modify(|w| w.set_dbp(true));
 
             // 2. Setup the LSE
             RCC.bdcr().modify(|w| {
@@ -231,17 +225,18 @@ pub(crate) unsafe fn init(config: Config) {
             // Wait until LSE is running
             while !RCC.bdcr().read().lserdy() {}
 
-            Rtc::set_clock_source(RCS::LSE);
+            BackupDomain::set_rtc_clock_source(RtcClockSource::LSE);
         }
-        RtcClockSource::LSI32 => {
+        RtcClockSource::LSI => {
             // Turn on the internal 32 kHz LSI oscillator
             RCC.csr().modify(|w| w.set_lsion(true));
 
             // Wait until LSI is running
             while !RCC.csr().read().lsirdy() {}
 
-            Rtc::set_clock_source(RCS::LSI);
+            BackupDomain::set_rtc_clock_source(RtcClockSource::LSI);
         }
+        _ => unreachable!(),
     }
 
     match config.mux {
@@ -266,7 +261,7 @@ pub(crate) unsafe fn init(config: Config) {
                 w.set_msirange(range.into());
                 w.set_msion(true);
 
-                if let RtcClockSource::LSE32 = config.rtc_mux {
+                if let RtcClockSource::LSE = config.rtc_mux {
                     // If LSE is enabled, enable calibration of MSI
                     w.set_msipllen(true);
                 } else {
diff --git a/embassy-stm32/src/rtc/datetime.rs b/embassy-stm32/src/rtc/datetime.rs
index a9c48d88d..3efe9be5d 100644
--- a/embassy-stm32/src/rtc/datetime.rs
+++ b/embassy-stm32/src/rtc/datetime.rs
@@ -89,7 +89,7 @@ pub enum DayOfWeek {
 #[cfg(feature = "chrono")]
 impl From<chrono::Weekday> for DayOfWeek {
     fn from(weekday: Weekday) -> Self {
-        day_of_week_from_u8(weekday.number_from_monday() as u8).unwrap()
+        day_of_week_from_u8(weekday.num_days_from_monday() as u8).unwrap()
     }
 }
 
diff --git a/embassy-stm32/src/rtc/mod.rs b/embassy-stm32/src/rtc/mod.rs
index 1f1abb78d..c408b2d61 100644
--- a/embassy-stm32/src/rtc/mod.rs
+++ b/embassy-stm32/src/rtc/mod.rs
@@ -10,6 +10,8 @@ use embassy_sync::blocking_mutex::raw::CriticalSectionRawMutex;
 use embassy_sync::blocking_mutex::Mutex;
 
 pub use self::datetime::{DateTime, DayOfWeek, Error as DateTimeError};
+use crate::rcc::bd::BackupDomain;
+pub use crate::rcc::RtcClockSource;
 
 /// refer to AN4759 to compare features of RTC2 and RTC3
 #[cfg_attr(any(rtc_v1), path = "v1.rs")]
@@ -107,19 +109,6 @@ pub struct Rtc {
     stop_time: Mutex<CriticalSectionRawMutex, Cell<Option<RtcInstant>>>,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
-#[repr(u8)]
-pub enum RtcClockSource {
-    /// 00: No clock
-    NoClock = 0b00,
-    /// 01: LSE oscillator clock used as RTC clock
-    LSE = 0b01,
-    /// 10: LSI oscillator clock used as RTC clock
-    LSI = 0b10,
-    /// 11: HSE oscillator clock divided by 32 used as RTC clock
-    HSE = 0b11,
-}
-
 #[derive(Copy, Clone, PartialEq)]
 pub struct RtcConfig {
     /// Asynchronous prescaler factor
@@ -189,7 +178,7 @@ impl Rtc {
             stop_time: Mutex::const_new(CriticalSectionRawMutex::new(), Cell::new(None)),
         };
 
-        Self::enable();
+        BackupDomain::enable_rtc();
 
         rtc_struct.configure(rtc_config);
         rtc_struct.rtc_config = rtc_config;
diff --git a/embassy-stm32/src/rtc/v2.rs b/embassy-stm32/src/rtc/v2.rs
index bf926f986..1e0ca9b48 100644
--- a/embassy-stm32/src/rtc/v2.rs
+++ b/embassy-stm32/src/rtc/v2.rs
@@ -2,7 +2,7 @@ use stm32_metapac::rtc::vals::{Init, Osel, Pol};
 
 #[cfg(feature = "low-power")]
 use super::RtcInstant;
-use super::{sealed, RtcClockSource, RtcConfig};
+use super::{sealed, RtcConfig};
 use crate::pac::rtc::Rtc;
 use crate::peripherals::RTC;
 use crate::rtc::sealed::Instance;
@@ -73,22 +73,6 @@ impl WakeupPrescaler {
 }
 
 impl super::Rtc {
-    fn unlock_registers() {
-        #[cfg(any(rtc_v2f2, rtc_v2f3, rtc_v2l1))]
-        let cr = crate::pac::PWR.cr();
-        #[cfg(any(rtc_v2f4, rtc_v2f7, rtc_v2h7, rtc_v2l4, rtc_v2wb))]
-        let cr = crate::pac::PWR.cr1();
-
-        // TODO: Missing from PAC for l0 and f0?
-        #[cfg(not(any(rtc_v2f0, rtc_v2l0)))]
-        {
-            if !cr.read().dbp() {
-                cr.modify(|w| w.set_dbp(true));
-                while !cr.read().dbp() {}
-            }
-        }
-    }
-
     #[cfg(feature = "low-power")]
     /// start the wakeup alarm and wtih a duration that is as close to but less than
     /// the requested duration, and record the instant the wakeup alarm was started
@@ -155,69 +139,6 @@ impl super::Rtc {
         })
     }
 
-    #[allow(dead_code)]
-    pub(crate) fn set_clock_source(clock_source: RtcClockSource) {
-        #[cfg(not(rtc_v2wb))]
-        use stm32_metapac::rcc::vals::Rtcsel;
-
-        #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
-        let cr = crate::pac::RCC.bdcr();
-        #[cfg(any(rtc_v2l0, rtc_v2l1))]
-        let cr = crate::pac::RCC.csr();
-
-        Self::unlock_registers();
-
-        cr.modify(|w| {
-            // Select RTC source
-            #[cfg(not(rtc_v2wb))]
-            w.set_rtcsel(Rtcsel::from_bits(clock_source as u8));
-            #[cfg(rtc_v2wb)]
-            w.set_rtcsel(clock_source as u8);
-        });
-    }
-
-    pub(super) fn enable() {
-        #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
-        let reg = crate::pac::RCC.bdcr().read();
-        #[cfg(any(rtc_v2l0, rtc_v2l1))]
-        let reg = crate::pac::RCC.csr().read();
-
-        #[cfg(any(rtc_v2h7, rtc_v2l4, rtc_v2wb))]
-        assert!(!reg.lsecsson(), "RTC is not compatible with LSE CSS, yet.");
-
-        if !reg.rtcen() {
-            Self::unlock_registers();
-
-            #[cfg(not(any(rtc_v2l0, rtc_v2l1, rtc_v2f2)))]
-            crate::pac::RCC.bdcr().modify(|w| w.set_bdrst(true));
-            #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
-            let cr = crate::pac::RCC.bdcr();
-            #[cfg(any(rtc_v2l0, rtc_v2l1))]
-            let cr = crate::pac::RCC.csr();
-
-            cr.modify(|w| {
-                // Reset
-                #[cfg(not(any(rtc_v2l0, rtc_v2l1)))]
-                w.set_bdrst(false);
-
-                w.set_rtcen(true);
-                w.set_rtcsel(reg.rtcsel());
-
-                // Restore bcdr
-                #[cfg(any(rtc_v2l4, rtc_v2wb))]
-                w.set_lscosel(reg.lscosel());
-                #[cfg(any(rtc_v2l4, rtc_v2wb))]
-                w.set_lscoen(reg.lscoen());
-
-                w.set_lseon(reg.lseon());
-
-                #[cfg(any(rtc_v2f0, rtc_v2f7, rtc_v2h7, rtc_v2l4, rtc_v2wb))]
-                w.set_lsedrv(reg.lsedrv());
-                w.set_lsebyp(reg.lsebyp());
-            });
-        }
-    }
-
     /// Applies the RTC config
     /// It this changes the RTC clock source the time will be reset
     pub(super) fn configure(&mut self, rtc_config: RtcConfig) {
diff --git a/embassy-stm32/src/rtc/v3.rs b/embassy-stm32/src/rtc/v3.rs
index 3297303ee..12952b15a 100644
--- a/embassy-stm32/src/rtc/v3.rs
+++ b/embassy-stm32/src/rtc/v3.rs
@@ -1,74 +1,11 @@
 use stm32_metapac::rtc::vals::{Calp, Calw16, Calw8, Fmt, Init, Key, Osel, Pol, TampalrmPu, TampalrmType};
 
-use super::{sealed, RtcCalibrationCyclePeriod, RtcClockSource, RtcConfig};
+use super::{sealed, RtcCalibrationCyclePeriod, RtcConfig};
 use crate::pac::rtc::Rtc;
 use crate::peripherals::RTC;
 use crate::rtc::sealed::Instance;
 
 impl super::Rtc {
-    fn unlock_registers() {
-        // Unlock the backup domain
-        #[cfg(not(any(rtc_v3u5, rcc_wl5, rcc_wle)))]
-        {
-            if !crate::pac::PWR.cr1().read().dbp() {
-                crate::pac::PWR.cr1().modify(|w| w.set_dbp(true));
-                while !crate::pac::PWR.cr1().read().dbp() {}
-            }
-        }
-        #[cfg(any(rcc_wl5, rcc_wle))]
-        {
-            use crate::pac::pwr::vals::Dbp;
-
-            if crate::pac::PWR.cr1().read().dbp() != Dbp::ENABLED {
-                crate::pac::PWR.cr1().modify(|w| w.set_dbp(Dbp::ENABLED));
-                while crate::pac::PWR.cr1().read().dbp() != Dbp::ENABLED {}
-            }
-        }
-    }
-
-    #[allow(dead_code)]
-    pub(crate) fn set_clock_source(clock_source: RtcClockSource) {
-        let clock_source = clock_source as u8;
-        #[cfg(not(any(rcc_wl5, rcc_wle)))]
-        let clock_source = crate::pac::rcc::vals::Rtcsel::from_bits(clock_source);
-
-        Self::unlock_registers();
-
-        crate::pac::RCC.bdcr().modify(|w| {
-            // Select RTC source
-            w.set_rtcsel(clock_source);
-        });
-    }
-
-    pub(super) fn enable() {
-        let bdcr = crate::pac::RCC.bdcr();
-
-        let reg = bdcr.read();
-        assert!(!reg.lsecsson(), "RTC is not compatible with LSE CSS, yet.");
-
-        if !reg.rtcen() {
-            Self::unlock_registers();
-
-            bdcr.modify(|w| w.set_bdrst(true));
-
-            bdcr.modify(|w| {
-                // Reset
-                w.set_bdrst(false);
-
-                w.set_rtcen(true);
-                w.set_rtcsel(reg.rtcsel());
-
-                // Restore bcdr
-                w.set_lscosel(reg.lscosel());
-                w.set_lscoen(reg.lscoen());
-
-                w.set_lseon(reg.lseon());
-                w.set_lsedrv(reg.lsedrv());
-                w.set_lsebyp(reg.lsebyp());
-            });
-        }
-    }
-
     /// Applies the RTC config
     /// It this changes the RTC clock source the time will be reset
     pub(super) fn configure(&mut self, rtc_config: RtcConfig) {
diff --git a/examples/stm32f4/src/bin/rtc.rs b/examples/stm32f4/src/bin/rtc.rs
index 0eca58203..23ff8ac47 100644
--- a/examples/stm32f4/src/bin/rtc.rs
+++ b/examples/stm32f4/src/bin/rtc.rs
@@ -5,13 +5,17 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::rtc::{Rtc, RtcConfig};
+use embassy_stm32::rtc::{Rtc, RtcClockSource, 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 = embassy_stm32::init(Default::default());
+    let mut config = Config::default();
+    config.rcc.rtc = Option::Some(RtcClockSource::LSI);
+    let p = embassy_stm32::init(config);
+
     info!("Hello World!");
 
     let now = NaiveDate::from_ymd_opt(2020, 5, 15)
@@ -23,8 +27,11 @@ async fn main(_spawner: Spawner) {
 
     rtc.set_datetime(now.into()).expect("datetime not set");
 
-    // In reality the delay would be much longer
-    Timer::after(Duration::from_millis(20000)).await;
+    loop {
+        let now: NaiveDateTime = rtc.now().unwrap().into();
+
+        info!("{}", now.timestamp());
 
-    let _then: NaiveDateTime = rtc.now().unwrap().into();
+        Timer::after(Duration::from_millis(1000)).await;
+    }
 }
diff --git a/examples/stm32l4/src/bin/rtc.rs b/examples/stm32l4/src/bin/rtc.rs
index 294ea456c..f3f8aa46f 100644
--- a/examples/stm32l4/src/bin/rtc.rs
+++ b/examples/stm32l4/src/bin/rtc.rs
@@ -23,7 +23,7 @@ async fn main(_spawner: Spawner) {
             PLLMul::Mul20,
             None,
         );
-        config.rcc.rtc_mux = rcc::RtcClockSource::LSE32;
+        config.rcc.rtc_mux = rcc::RtcClockSource::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 148c58771..0a677be76 100644
--- a/examples/stm32l4/src/bin/spe_adin1110_http_server.rs
+++ b/examples/stm32l4/src/bin/spe_adin1110_http_server.rs
@@ -84,7 +84,7 @@ async fn main(spawner: Spawner) {
         None,
     );
     config.rcc.hsi48 = true; // needed for rng
-    config.rcc.rtc_mux = rcc::RtcClockSource::LSI32;
+    config.rcc.rtc_mux = rcc::RtcClockSource::LSI;
 
     let dp = embassy_stm32::init(config);
 
diff --git a/examples/stm32wl/src/bin/rtc.rs b/examples/stm32wl/src/bin/rtc.rs
index fb1bc6e3d..2be6c7b93 100644
--- a/examples/stm32wl/src/bin/rtc.rs
+++ b/examples/stm32wl/src/bin/rtc.rs
@@ -5,8 +5,8 @@
 use chrono::{NaiveDate, NaiveDateTime};
 use defmt::*;
 use embassy_executor::Spawner;
-use embassy_stm32::rcc::{self, ClockSrc};
-use embassy_stm32::rtc::{Rtc, RtcConfig};
+use embassy_stm32::rcc::ClockSrc;
+use embassy_stm32::rtc::{Rtc, RtcClockSource, RtcConfig};
 use embassy_stm32::Config;
 use embassy_time::{Duration, Timer};
 use {defmt_rtt as _, panic_probe as _};
@@ -16,7 +16,7 @@ async fn main(_spawner: Spawner) {
     let p = {
         let mut config = Config::default();
         config.rcc.mux = ClockSrc::HSE32;
-        config.rcc.rtc_mux = rcc::RtcClockSource::LSE32;
+        config.rcc.rtc_mux = RtcClockSource::LSE;
         config.rcc.enable_rtc_apb = true;
         embassy_stm32::init(config)
     };
diff --git a/tests/stm32/src/bin/rtc.rs b/tests/stm32/src/bin/rtc.rs
index 7df415b44..1a64dd387 100644
--- a/tests/stm32/src/bin/rtc.rs
+++ b/tests/stm32/src/bin/rtc.rs
@@ -10,7 +10,8 @@ use chrono::{NaiveDate, NaiveDateTime};
 use common::*;
 use defmt::assert;
 use embassy_executor::Spawner;
-use embassy_stm32::rtc::{Rtc, RtcClockSource, RtcConfig};
+use embassy_stm32::rcc::RtcClockSource;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_time::{Duration, Timer};
 
 #[embassy_executor::main]
diff --git a/tests/stm32/src/bin/stop.rs b/tests/stm32/src/bin/stop.rs
index 4a49bde9d..0b3f4a300 100644
--- a/tests/stm32/src/bin/stop.rs
+++ b/tests/stm32/src/bin/stop.rs
@@ -11,7 +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::rtc::{Rtc, RtcClockSource, RtcConfig};
+use embassy_stm32::rcc::RtcClockSource;
+use embassy_stm32::rtc::{Rtc, RtcConfig};
 use embassy_time::{Duration, Timer};
 use static_cell::make_static;