diff --git a/embassy-stm32/src/timer/one_pulse.rs b/embassy-stm32/src/timer/one_pulse.rs
index 47c1d7f49..e89ad8390 100644
--- a/embassy-stm32/src/timer/one_pulse.rs
+++ b/embassy-stm32/src/timer/one_pulse.rs
@@ -7,7 +7,7 @@ use core::pin::Pin;
 use core::task::{Context, Poll};
 
 use super::low_level::{
-    CountingMode, FilterValue, InputCaptureMode, InputTISelection, SlaveMode, Timer, TriggerSource,
+    CountingMode, FilterValue, InputCaptureMode, InputTISelection, SlaveMode, Timer, TriggerSource as Ts,
 };
 use super::{CaptureCompareInterruptHandler, ExternalTriggerPin, GeneralInstance4Channel, TimerChannel, TimerPin};
 pub use super::{Ch1, Ch2};
@@ -46,33 +46,71 @@ pub struct TriggerPin<'d, T, C> {
     phantom: PhantomData<(T, C)>,
 }
 
-// TODO: Generify trigger inputs
+trait SealedTriggerSource {}
 
-impl<'d, T: GeneralInstance4Channel> TriggerPin<'d, T, Ch1> {
+/// Marker trait for a trigger source.
+#[expect(private_bounds)]
+pub trait TriggerSource: SealedTriggerSource {}
+
+impl TriggerSource for Ch1 {}
+impl TriggerSource for Ch2 {}
+impl TriggerSource for Ext {}
+
+impl SealedTriggerSource for Ch1 {}
+impl SealedTriggerSource for Ch2 {}
+impl SealedTriggerSource for Ext {}
+
+trait SealedTimerTriggerPin<T, S>: crate::gpio::Pin {}
+
+/// Marker trait for a trigger pin.
+#[expect(private_bounds)]
+// TODO: find better naming scheme than prefixing all pin traits with "Timer".
+// The trait name cannot conflict with the corresponding type's name.
+// Applies to other timer submodules as well.
+pub trait TimerTriggerPin<T, S>: SealedTimerTriggerPin<T, S> {
+    /// Get the AF number needed to use this pin as a trigger source.
+    fn af_num(&self) -> u8;
+}
+
+impl<T, P, C> TimerTriggerPin<T, C> for P
+where
+    T: GeneralInstance4Channel,
+    P: TimerPin<T, C>,
+    C: super::Channel + TriggerSource,
+{
+    fn af_num(&self) -> u8 {
+        TimerPin::af_num(self)
+    }
+}
+
+impl<T, P> TimerTriggerPin<T, Ext> for P
+where
+    T: GeneralInstance4Channel,
+    P: ExternalTriggerPin<T>,
+{
+    fn af_num(&self) -> u8 {
+        ExternalTriggerPin::af_num(self)
+    }
+}
+
+impl<T, P, C> SealedTimerTriggerPin<T, C> for P
+where
+    T: GeneralInstance4Channel,
+    P: TimerPin<T, C>,
+    C: super::Channel + TriggerSource,
+{
+}
+
+impl<T, P> SealedTimerTriggerPin<T, Ext> for P
+where
+    T: GeneralInstance4Channel,
+    P: ExternalTriggerPin<T>,
+{
+}
+
+impl<'d, T: GeneralInstance4Channel, C: TriggerSource> TriggerPin<'d, T, C> {
     /// "Create a new Ch1 trigger pin instance.
-    pub fn new_ch1(pin: Peri<'d, impl TimerPin<T, Ch1>>, pull: Pull) -> Self {
-        pin.set_as_af(pin.af_num(), AfType::input(pull));
-        TriggerPin {
-            _pin: pin.into(),
-            phantom: PhantomData,
-        }
-    }
-}
-
-impl<'d, T: GeneralInstance4Channel> TriggerPin<'d, T, Ch2> {
-    /// "Create a new Ch2 trigger pin instance.
-    pub fn new_ch2(pin: Peri<'d, impl TimerPin<T, Ch2>>, pull: Pull) -> Self {
-        pin.set_as_af(pin.af_num(), AfType::input(pull));
-        TriggerPin {
-            _pin: pin.into(),
-            phantom: PhantomData,
-        }
-    }
-}
-
-impl<'d, T: GeneralInstance4Channel> TriggerPin<'d, T, Ext> {
-    /// "Create a new EXT trigger pin instance.
-    pub fn new_ext(pin: Peri<'d, impl ExternalTriggerPin<T>>, pull: Pull) -> Self {
+    pub fn new(pin: Peri<'d, impl TimerTriggerPin<T, C>>, pull: Pull) -> Self {
         pin.set_as_af(pin.af_num(), AfType::input(pull));
         TriggerPin {
             _pin: pin.into(),
@@ -103,7 +141,7 @@ impl<'d, T: GeneralInstance4Channel> OnePulse<'d, T> {
     ) -> Self {
         let mut this = Self { inner: Timer::new(tim) };
 
-        this.inner.set_trigger_source(TriggerSource::TI1F_ED);
+        this.inner.set_trigger_source(Ts::TI1F_ED);
         this.inner
             .set_input_ti_selection(TimerChannel::Ch1, InputTISelection::Normal);
         this.inner
@@ -128,7 +166,7 @@ impl<'d, T: GeneralInstance4Channel> OnePulse<'d, T> {
     ) -> Self {
         let mut this = Self { inner: Timer::new(tim) };
 
-        this.inner.set_trigger_source(TriggerSource::TI1FP1);
+        this.inner.set_trigger_source(Ts::TI1FP1);
         this.inner
             .set_input_ti_selection(TimerChannel::Ch1, InputTISelection::Normal);
         this.inner
@@ -154,7 +192,7 @@ impl<'d, T: GeneralInstance4Channel> OnePulse<'d, T> {
     ) -> Self {
         let mut this = Self { inner: Timer::new(tim) };
 
-        this.inner.set_trigger_source(TriggerSource::TI2FP2);
+        this.inner.set_trigger_source(Ts::TI2FP2);
         this.inner
             .set_input_ti_selection(TimerChannel::Ch2, InputTISelection::Normal);
         this.inner
@@ -186,7 +224,7 @@ impl<'d, T: GeneralInstance4Channel> OnePulse<'d, T> {
             // No filtering
             r.set_etf(FilterValue::NO_FILTER);
         });
-        this.inner.set_trigger_source(TriggerSource::ETRF);
+        this.inner.set_trigger_source(Ts::ETRF);
         this.new_inner(freq, pulse_end, counting_mode);
 
         this
diff --git a/embassy-stm32/src/timer/qei.rs b/embassy-stm32/src/timer/qei.rs
index bc7e71290..657052cfa 100644
--- a/embassy-stm32/src/timer/qei.rs
+++ b/embassy-stm32/src/timer/qei.rs
@@ -8,6 +8,7 @@ use super::low_level::Timer;
 pub use super::{Ch1, Ch2};
 use super::{GeneralInstance4Channel, TimerPin};
 use crate::gpio::{AfType, AnyPin, Pull};
+use crate::timer::Channel;
 use crate::Peri;
 
 /// Counting direction
@@ -24,28 +25,31 @@ pub struct QeiPin<'d, T, Channel> {
     phantom: PhantomData<(T, Channel)>,
 }
 
-// TODO: generify QEI channels
-
-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, $channel>>) -> 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> QeiPin<'d, T, C> {
+    /// Create a new  QEI pin instance.
+    pub fn new(pin: Peri<'d, impl TimerPin<T, C>>) -> Self {
+        critical_section::with(|_| {
+            pin.set_low();
+            pin.set_as_af(pin.af_num(), AfType::input(Pull::None));
+        });
+        QeiPin {
+            _pin: pin.into(),
+            phantom: PhantomData,
         }
-    };
+    }
 }
 
-channel_impl!(new_ch1, Ch1, TimerPin);
-channel_impl!(new_ch2, Ch2, TimerPin);
+trait SealedQeiChannel: Channel {}
+
+/// 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> {