From ac7c44c1d1465bd125ef9a2c6da7e3b42a52569c Mon Sep 17 00:00:00 2001
From: Tobias Naumann <tobias.naumann@iml.fraunhofer.de>
Date: Fri, 21 Mar 2025 13:27:29 +0100
Subject: [PATCH] Use write closure to clear idle flag, only read rdr on usart
 versions which need it

---
 embassy-stm32/src/usart/ringbuffered.rs | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/embassy-stm32/src/usart/ringbuffered.rs b/embassy-stm32/src/usart/ringbuffered.rs
index f1161aa79..d76a52d1e 100644
--- a/embassy-stm32/src/usart/ringbuffered.rs
+++ b/embassy-stm32/src/usart/ringbuffered.rs
@@ -261,14 +261,13 @@ fn clear_idle_flag(r: Regs) -> Sr {
 
     let sr = sr(r).read();
 
-    // This read also clears the error and idle interrupt flags on v1.
-    unsafe { rdr(r).read_volatile() };
     #[cfg(any(usart_v3, usart_v4))]
-    {
-        let mut clear_idle = regs::Icr(0);
-        clear_idle.set_idle(true);
-        r.icr().write_value(clear_idle);
-    }
+    r.icr().write(|w| w.set_idle(true));
+    #[cfg(not(any(usart_v3, usart_v4)))]
+    unsafe {
+        // This read also clears the error and idle interrupt flags on v1.
+        rdr(r).read_volatile()
+    };
 
     r.cr1().modify(|w| w.set_idleie(true));