From 5fcebd28f477f9e34ae2075b0cb6afdd545689ce Mon Sep 17 00:00:00 2001
From: Bartek <bartek.ko@gmail.com>
Date: Tue, 1 Aug 2023 13:46:34 +0930
Subject: [PATCH] Fix unlocking the backup domain when enabling LSE

Set PWREN bit to enable the power interface clock before enabling access to the backup domain.
---
 embassy-stm32/src/rcc/l4.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/embassy-stm32/src/rcc/l4.rs b/embassy-stm32/src/rcc/l4.rs
index 237b7bc91..36c9eb2f5 100644
--- a/embassy-stm32/src/rcc/l4.rs
+++ b/embassy-stm32/src/rcc/l4.rs
@@ -412,6 +412,7 @@ pub(crate) unsafe fn init(config: Config) {
     match config.rtc_mux {
         RtcClockSource::LSE32 => {
             // 1. Unlock the backup domain
+            RCC.apb1enr1().modify(|w| w.set_pwren(true));
             PWR.cr1().modify(|w| w.set_dbp(true));
 
             // 2. Setup the LSE