add back optional cortex-m interrupt number impl generation

.github/workflows/ci.yml

@@ -83,6 +83,7 @@ jobs:
           - { vendor: Spansion, options: "-- --atomics" }
           - { vendor: STMicro }
           - { vendor: STMicro, options: "-- --atomics" }
+          - { vendor: STMicro, options: "-- --add-cortex-m-int-num" }
           - {
               vendor: STMicro,
               options: "-- --strict -f enum_value::p: --max-cluster-size --atomics --atomics-feature atomics --impl-debug --impl-defmt defmt",

CHANGELOG.md

@@ -10,9 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/).
 - Use marker struct instead of address in `Periph` with `PeripheralSpec` trait
 - Add `--skip-peripherals-struct` flag to skip generating the `Peripherals`
   struct, its `take`/`steal` impl and the `DEVICE_PERIPHERALS` static
-- Generated `cortex-m` PACs now implement the `cortex_m_types::InterruptNumber` trait instead
-  of `cortex-m::interrupt::InterruptNumber` to avoid a hard dependency on `cortex-m` for PACs.
-  PACs should now use the `cortex-m-types` dependency instead of `cortex-m`.
+- Generated `cortex-m` PACs now implement the `cortex_m_types::InterruptNumber` trait instead of
+  the `cortex-m::interrupt::InterruptNumber` trait. A new `add-cortex-m-int-num` option
+  which allows adding the generation of the old trait.
 - Bump MSRV of generated code to 1.81
 
 ## [v0.37.1] - 2025-10-17

src/config.rs

@@ -38,6 +38,8 @@ pub struct Config {
     pub interrupt_link_section: Option<String>,
     pub reexport_core_peripherals: bool,
     pub reexport_interrupt: bool,
+    /// Also generating interrupt number trait implementation for `cortex-m` trait.
+    pub add_cortex_m_int_num: bool,
     pub ident_formats: IdentFormats,
     pub ident_formats_theme: Option<IdentFormatsTheme>,
     pub field_names_for_enums: bool,

src/generate/interrupt.rs

@@ -340,6 +340,17 @@ pub fn render(
                         }
                     }
                 });
+
+                if config.add_cortex_m_int_num {
+                    root.extend(quote! {
+                        unsafe impl cortex_m::interrupt::InterruptNumber for Interrupt {
+                            #[inline(always)]
+                            fn number(#self_token) -> u16 {
+                                #self_token as u16
+                            }
+                        }
+                    });
+                }
             }
             Target::XtensaLX => {
                 root.extend(quote! {

src/main.rs

@@ -279,6 +279,15 @@ Allowed cases are `unchanged` (''), `pascal` ('p'), `constant` ('c') and `snake`
                 .action(ArgAction::SetTrue)
                 .help("Reexport interrupt macro from cortex-m-rt like crates"),
         )
+        .arg(
+            Arg::new("add_cortex_m_int_num")
+                .long("add-cortex-m-int-num")
+                .alias("add_cortex_m_int_num")
+                .action(ArgAction::SetTrue)
+                .help("Add the generation for the cortex-m InterruptNumber trait impl")
+                .long_help("Add the generation for the cortex-m InterruptNumber trait impl.
+The generated crate will have a dependency on cortex-m.")
+        )
         .arg(
             Arg::new("base_address_shift")
                 .short('b')

svd2rust-regress/src/svd_test.rs

@@ -18,6 +18,7 @@ const CRATES_ALL: &[&str] = &[
 const CRATES_MSP430: &[&str] = &["msp430 = \"0.4.0\"", "msp430-rt = \"0.4.0\""];
 const CRATES_ATOMICS: &[&str] =
     &["portable-atomic = { version = \"1\", default-features = false }"];
+const CRATES_CORTEX_M_LEGACY_INT_NUM: &[&str] = &["cortex-m = { version = \"0.7\" }"];
 const CRATES_CORTEX_M: &[&str] = &["cortex-m-types = \"0.1\"", "cortex-m-rt = \"0.7\""];
 const CRATES_RISCV: &[&str] = &["riscv = \"0.12.1\"", "riscv-rt = \"0.13.0\""];
 const CRATES_MIPS: &[&str] = &["mips-mcu = \"0.1.0\""];
@@ -429,15 +430,16 @@ impl TestCase {
                 Target::XtensaLX => [].iter(),
                 Target::None => unreachable!(),
             })
-            .chain(if let Some(opts) = opts {
+            .chain(opts.as_ref().map_or(Vec::new().into_iter(), |opts| {
+                let mut fragments = Vec::new();
                 if opts.iter().any(|v| v.contains("atomics")) {
-                    CRATES_ATOMICS.iter()
-                } else {
-                    [].iter()
+                    fragments.extend(CRATES_ATOMICS);
                 }
-            } else {
-                [].iter()
-            })
+                if opts.iter().any(|v| v.contains("add-cortex-m-int-num")) {
+                    fragments.extend(CRATES_CORTEX_M_LEGACY_INT_NUM);
+                }
+                fragments.into_iter()
+            }))
             .chain(PROFILE_ALL.iter())
             .chain(FEATURES_ALL.iter())
             .chain(match &self.arch {