stm32/rcc: set rtc clock on f4

embassy-stm32/src/rcc/f4.rs

@@ -473,6 +473,11 @@ pub(crate) unsafe fn init(config: Config) {
         Rtc::set_clock_source(clock_source);
     });
 
+    let rtc = match config.rtc {
+        Some(RtcClockSource::LSI) => Some(LSI_FREQ),
+        _ => None,
+    };
+
     set_freqs(Clocks {
         sys: Hertz(sysclk),
         apb1: Hertz(pclk1),
@@ -492,6 +497,8 @@ pub(crate) unsafe fn init(config: Config) {
 
         #[cfg(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f446, stm32f469, stm32f479))]
         pllsai: None,
+
+        rtc: rtc,
     });
 }
 

embassy-stm32/src/rcc/mod.rs

@@ -74,7 +74,7 @@ pub struct Clocks {
     #[cfg(any(rcc_h5, rcc_h50, rcc_h7, rcc_h7ab))]
     pub adc: Option<Hertz>,
 
-    #[cfg(rcc_wb)]
+    #[cfg(any(rcc_wb, rcc_f4))]
     /// Set only if the lsi or lse is configured
     pub rtc: Option<Hertz>,
 }