diff --git a/rust/kernel/io/register.rs b/rust/kernel/io/register.rs
index 59908db011cd..03dfd2ff48c7 100644
--- a/rust/kernel/io/register.rs
+++ b/rust/kernel/io/register.rs
@@ -804,6 +804,9 @@ macro_rules! register {
     // Entry point for the macro, allowing multiple registers to be defined in one call.
     // It matches all possible register declaration patterns to dispatch them to corresponding
     // `@reg` rule that defines a single register.
+    //
+    // TODO: change `alias:ident` to `alias:path` once relative registers are replaced by I/O
+    // projections.
     (
         $(
             $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty)
@@ -837,7 +840,7 @@ macro_rules! register {
 
     // Creates an alias register of fixed offset register `alias` with its own fields.
     (
-        @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:ident
+        @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:path
             { $($fields:tt)* }
     ) => {
         $crate::register!(@bitfield $(#[$attr])* $vis struct $name($storage) { $($fields)* });
@@ -896,7 +899,7 @@ macro_rules! register {
 
     // Creates an alias of register `idx` of array of registers `alias` with its own fields.
     (
-        @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:ident [ $idx:expr ]
+        @reg $(#[$attr:meta])* $vis:vis $name:ident ($storage:ty) => $alias:path [ $idx:expr ]
             { $($fields:tt)* }
     ) => {
         $crate::build_assert::static_assert!(