Build script now injects EXTI2 => EXTI2_TSC peripheral/interrupt mapping if it's not present in the PAC, removed macro magic in exti that was working around this omission

3 files changed, 22 insertions, 19 deletions

diff --git a/embassy-stm32/CHANGELOG.md b/embassy-stm32/CHANGELOG.md
index 0f8113863..a66b2d437 100644
--- a/embassy-stm32/CHANGELOG.md
+++ b/embassy-stm32/CHANGELOG.md
@@ -77,7 +77,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - feat: stm32/flash: add async support for h7 family
 - feat: exti brought in line with other drivers' interrupt rebinding system ([#4922](https://github.com/embassy-rs/embassy/pull/4922))
 - removal: ExtiInput no longer accepts AnyPin/AnyChannel; AnyChannel removed entirely
-- change: build script now generates `unimpl_tsc` cfg option when a chip has a TSC peripheral but no driver
+- fix: build script ensures EXTI2_TSC is listed as the IRQ of EXTI2 even if the PAC doesn't
 - feat: stm32/lcd: added implementation
 
 ## 0.4.0 - 2025-08-26
diff --git a/embassy-stm32/build.rs b/embassy-stm32/build.rs
index 3d0b13fe2..109571e8f 100644
--- a/embassy-stm32/build.rs
+++ b/embassy-stm32/build.rs
@@ -56,16 +56,12 @@ fn main() {
 
     eprintln!("chip: {chip_name}");
 
-    cfgs.declare("unimpl_tsc");
     for p in METADATA.peripherals {
         if let Some(r) = &p.registers {
             cfgs.enable(r.kind);
             foreach_version_cfg(&mut cfgs, r.kind, r.version, |cfgs, cfg_name| {
                 cfgs.enable(cfg_name);
             });
-        } else if p.name == "TSC" {
-            //Even if the registers are missing, EXTI needs to know if TSC is present in silicon to know whether the EXTI2 interrupt is shadowed by EXTI2_TSC
-            cfgs.enable("unimpl_tsc")
         }
     }
 
@@ -357,8 +353,13 @@ fn main() {
     // ========
     // Generate interrupt declarations
 
+    let mut exti2_tsc_shared_int_present: Option<stm32_metapac::metadata::Interrupt> = None;
     let mut irqs = Vec::new();
     for irq in METADATA.interrupts {
+        // The PAC doesn't ensure this is listed as the IRQ of EXTI2, so we must do so
+        if irq.name == "EXTI2_TSC" {
+            exti2_tsc_shared_int_present = Some(irq.clone())
+        }
         irqs.push(format_ident!("{}", irq.name));
     }
 
@@ -1816,7 +1817,19 @@ fn main() {
     for p in METADATA.peripherals {
         let mut pt = TokenStream::new();
 
+        let mut exti2_tsc_injected = false;
+        if let Some(ref irq) = exti2_tsc_shared_int_present
+            && p.name == "EXTI"
+        {
+            exti2_tsc_injected = true;
+            let iname = format_ident!("{}", irq.name);
+            let sname = format_ident!("{}", "EXTI2");
+            pt.extend(quote!(pub type #sname = crate::interrupt::typelevel::#iname;));
+        }
         for irq in p.interrupts {
+            if exti2_tsc_injected && irq.signal == "EXTI2" {
+                continue;
+            }
             let iname = format_ident!("{}", irq.interrupt);
             let sname = format_ident!("{}", irq.signal);
             pt.extend(quote!(pub type #sname = crate::interrupt::typelevel::#iname;));
diff --git a/embassy-stm32/src/exti.rs b/embassy-stm32/src/exti.rs
index 57217034e..7b7896d46 100644
--- a/embassy-stm32/src/exti.rs
+++ b/embassy-stm32/src/exti.rs
@@ -395,40 +395,30 @@ pub struct AnyChannel {
 
 macro_rules! impl_exti {
     ($type:ident, $number:expr) => {
-        impl_exti!(@inner $type, $number, crate::_generated::peripheral_interrupts::EXTI::$type);
-    };
-    ($type:ident, $number:expr, @tsc) => {
-        impl_exti!(@inner $type, $number, crate::_generated::peripheral_interrupts::TSC::GLOBAL);
-    };
-    (@inner $type:ident, $number:expr, $irq:path) => {
         impl SealedChannel for crate::peripherals::$type {}
         impl Channel for crate::peripherals::$type {
             fn number(&self) -> PinNumber {
                 $number
             }
             fn irq(&self) -> InterruptEnum {
-                <$irq>::IRQ
+                crate::_generated::peripheral_interrupts::EXTI::$type::IRQ
             }
-            type IRQ = $irq;
+            type IRQ = crate::_generated::peripheral_interrupts::EXTI::$type;
         }
 
         //Still here to surface deprecation messages to the user - remove when removing AnyChannel
         #[allow(deprecated)]
         impl From<crate::peripherals::$type> for AnyChannel {
             fn from(_val: crate::peripherals::$type) -> Self {
-            Self {
-                number: $number,
+                Self { number: $number }
             }
-        }}
+        }
     };
 }
 
 impl_exti!(EXTI0, 0);
 impl_exti!(EXTI1, 1);
-#[cfg(not(any(tsc, unimpl_tsc)))]
 impl_exti!(EXTI2, 2);
-#[cfg(any(tsc, unimpl_tsc))]
-impl_exti!(EXTI2, 2, @tsc);
 impl_exti!(EXTI3, 3);
 impl_exti!(EXTI4, 4);
 impl_exti!(EXTI5, 5);