1 files changed, 34 insertions, 22 deletions

diff --git a/embassy-stm32/src/timer/qei.rs b/embassy-stm32/src/timer/qei.rs
index f3c81667c..82b5968b0 100644
--- a/embassy-stm32/src/timer/qei.rs
+++ b/embassy-stm32/src/timer/qei.rs
@@ -6,8 +6,9 @@ use stm32_metapac::timer::vals;
 
 use super::low_level::Timer;
 pub use super::{Ch1, Ch2};
-use super::{Channel1Pin, Channel2Pin, GeneralInstance4Channel};
+use super::{GeneralInstance4Channel, TimerPin};
 use crate::gpio::{AfType, AnyPin, Pull};
+use crate::timer::TimerChannel;
 use crate::Peri;
 
 /// Counting direction
@@ -19,31 +20,37 @@ pub enum Direction {
 }
 
 /// Wrapper for using a pin with QEI.
-pub struct QeiPin<'d, T, Channel> {
-    _pin: Peri<'d, AnyPin>,
-    phantom: PhantomData<(T, Channel)>,
+pub struct QeiPin<'d, T, Channel, #[cfg(afio)] A> {
+    #[allow(unused)]
+    pin: Peri<'d, AnyPin>,
+    phantom: PhantomData<if_afio!((T, Channel, A))>,
 }
 
-macro_rules! channel_impl {
-    ($new_chx:ident, $channel:ident, $pin_trait:ident) => {
-        impl<'d, T: GeneralInstance4Channel> QeiPin<'d, T, $channel> {
-            #[doc = concat!("Create a new ", stringify!($channel), " QEI pin instance.")]
-            pub fn $new_chx(pin: Peri<'d, impl $pin_trait<T>>) -> Self {
-                critical_section::with(|_| {
-                    pin.set_low();
-                    pin.set_as_af(pin.af_num(), AfType::input(Pull::None));
-                });
-                QeiPin {
-                    _pin: pin.into(),
-                    phantom: PhantomData,
-                }
-            }
+impl<'d, T: GeneralInstance4Channel, C: QeiChannel, #[cfg(afio)] A> if_afio!(QeiPin<'d, T, C, A>) {
+    /// Create a new QEI pin instance.
+    pub fn new(pin: Peri<'d, if_afio!(impl TimerPin<T, C, A>)>) -> Self {
+        critical_section::with(|_| {
+            pin.set_low();
+            set_as_af!(pin, AfType::input(Pull::None));
+        });
+        QeiPin {
+            pin: pin.into(),
+            phantom: PhantomData,
         }
-    };
+    }
 }
 
-channel_impl!(new_ch1, Ch1, Channel1Pin);
-channel_impl!(new_ch2, Ch2, Channel2Pin);
+trait SealedQeiChannel: TimerChannel {}
+
+/// Marker trait for a timer channel eligible for use with QEI.
+#[expect(private_bounds)]
+pub trait QeiChannel: SealedQeiChannel {}
+
+impl QeiChannel for Ch1 {}
+impl QeiChannel for Ch2 {}
+
+impl SealedQeiChannel for Ch1 {}
+impl SealedQeiChannel for Ch2 {}
 
 /// Quadrature decoder driver.
 pub struct Qei<'d, T: GeneralInstance4Channel> {
@@ -52,7 +59,12 @@ pub struct Qei<'d, T: GeneralInstance4Channel> {
 
 impl<'d, T: GeneralInstance4Channel> Qei<'d, T> {
     /// Create a new quadrature decoder driver.
-    pub fn new(tim: Peri<'d, T>, _ch1: QeiPin<'d, T, Ch1>, _ch2: QeiPin<'d, T, Ch2>) -> Self {
+    #[allow(unused)]
+    pub fn new<#[cfg(afio)] A>(
+        tim: Peri<'d, T>,
+        ch1: if_afio!(QeiPin<'d, T, Ch1, A>),
+        ch2: if_afio!(QeiPin<'d, T, Ch2, A>),
+    ) -> Self {
         Self::new_inner(tim)
     }