From 0591d60a7931255fd1161608c69c4935d6a16676 Mon Sep 17 00:00:00 2001
From: Dario Nieuwenhuis <dirbaio@dirbaio.net>
Date: Wed, 30 Apr 2025 18:00:17 +0200
Subject: [PATCH] stm32/otg: calculate TRDT using AHB freq instead of kernel
 freq.

---
 embassy-stm32/build.rs       | 5 +++++
 embassy-stm32/src/rcc/mod.rs | 2 ++
 embassy-stm32/src/usb/otg.rs | 2 +-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/embassy-stm32/build.rs b/embassy-stm32/build.rs
index f9f03c51b..3fefa9717 100644
--- a/embassy-stm32/build.rs
+++ b/embassy-stm32/build.rs
@@ -647,6 +647,8 @@ fn main() {
                 PeripheralRccKernelClock::Clock(clock) => clock_gen.gen_clock(p.name, clock),
             };
 
+            let bus_clock_frequency = clock_gen.gen_clock(p.name, &rcc.bus_clock);
+
             // A refcount leak can result if the same field is shared by peripherals with different stop modes
             // This condition should be checked in stm32-data
             let stop_mode = match rcc.stop_mode {
@@ -660,6 +662,9 @@ fn main() {
                     fn frequency() -> crate::time::Hertz {
                         #clock_frequency
                     }
+                    fn bus_frequency() -> crate::time::Hertz {
+                        #bus_clock_frequency
+                    }
 
                     const RCC_INFO: crate::rcc::RccInfo = unsafe {
                         crate::rcc::RccInfo::new(
diff --git a/embassy-stm32/src/rcc/mod.rs b/embassy-stm32/src/rcc/mod.rs
index 4f43d3748..150daa4a7 100644
--- a/embassy-stm32/src/rcc/mod.rs
+++ b/embassy-stm32/src/rcc/mod.rs
@@ -97,6 +97,8 @@ pub(crate) unsafe fn get_freqs() -> &'static Clocks {
 
 pub(crate) trait SealedRccPeripheral {
     fn frequency() -> Hertz;
+    #[allow(dead_code)]
+    fn bus_frequency() -> Hertz;
     const RCC_INFO: RccInfo;
 }
 
diff --git a/embassy-stm32/src/usb/otg.rs b/embassy-stm32/src/usb/otg.rs
index 2aca3d929..590d1a427 100644
--- a/embassy-stm32/src/usb/otg.rs
+++ b/embassy-stm32/src/usb/otg.rs
@@ -549,7 +549,7 @@ foreach_interrupt!(
 );
 
 fn calculate_trdt<T: Instance>(speed: Dspd) -> u8 {
-    let ahb_freq = T::frequency().0;
+    let ahb_freq = T::bus_frequency().0;
     match speed {
         Dspd::HIGH_SPEED => {
             // From RM0431 (F72xx), RM0090 (F429), RM0390 (F446)