From 416ecc73d8211e348bf51a5cfe84075673b18963 Mon Sep 17 00:00:00 2001
From: xoviat <xoviat@users.noreply.github.com>
Date: Tue, 29 Aug 2023 20:06:53 -0500
Subject: [PATCH] add qei draft

---
 embassy-stm32/src/timer/qei.rs | 142 +++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)
 create mode 100644 embassy-stm32/src/timer/qei.rs

diff --git a/embassy-stm32/src/timer/qei.rs b/embassy-stm32/src/timer/qei.rs
new file mode 100644
index 00000000..fa881472
--- /dev/null
+++ b/embassy-stm32/src/timer/qei.rs
@@ -0,0 +1,142 @@
+//! # Quadrature Encoder Interface
+use crate::{
+    gpio::PushPull,
+    pac, rcc,
+    timer::{CPin, General},
+};
+
+pub trait QeiExt: Sized + Instance {
+    fn qei(
+        self,
+        pins: (
+            impl Into<<Self as CPin<0>>::Ch<PushPull>>,
+            impl Into<<Self as CPin<1>>::Ch<PushPull>>,
+        ),
+    ) -> Qei<Self>;
+}
+
+impl<TIM: Instance> QeiExt for TIM {
+    fn qei(
+        self,
+        pins: (
+            impl Into<<Self as CPin<0>>::Ch<PushPull>>,
+            impl Into<<Self as CPin<1>>::Ch<PushPull>>,
+        ),
+    ) -> Qei<Self> {
+        Qei::new(self, pins)
+    }
+}
+
+/// Hardware quadrature encoder interface peripheral
+pub struct Qei<TIM: Instance> {
+    tim: TIM,
+    pins: (
+        <TIM as CPin<0>>::Ch<PushPull>,
+        <TIM as CPin<1>>::Ch<PushPull>,
+    ),
+}
+
+impl<TIM: Instance> Qei<TIM> {
+    /// Configures a TIM peripheral as a quadrature encoder interface input
+    pub fn new(
+        mut tim: TIM,
+        pins: (
+            impl Into<<TIM as CPin<0>>::Ch<PushPull>>,
+            impl Into<<TIM as CPin<1>>::Ch<PushPull>>,
+        ),
+    ) -> Self {
+        // Enable and reset clock.
+        unsafe {
+            TIM::enable_unchecked();
+            TIM::reset_unchecked();
+        }
+
+        let pins = (pins.0.into(), pins.1.into());
+        tim.setup_qei();
+
+        Qei { tim, pins }
+    }
+
+    /// Releases the TIM peripheral and QEI pins
+    #[allow(clippy::type_complexity)]
+    pub fn release(
+        self,
+    ) -> (
+        TIM,
+        (
+            <TIM as CPin<0>>::Ch<PushPull>,
+            <TIM as CPin<1>>::Ch<PushPull>,
+        ),
+    ) {
+        (self.tim, self.pins)
+    }
+
+    /// Set current count number
+    pub fn set_count(&mut self, value: TIM::Width) -> &mut Self {
+        self.tim.write_count(value);
+        self
+    }
+}
+
+impl<TIM: Instance> embedded_hal::Qei for Qei<TIM> {
+    type Count = TIM::Width;
+
+    fn count(&self) -> Self::Count {
+        self.tim.read_count()
+    }
+
+    fn direction(&self) -> embedded_hal::Direction {
+        if self.tim.read_direction() {
+            embedded_hal::Direction::Upcounting
+        } else {
+            embedded_hal::Direction::Downcounting
+        }
+    }
+}
+
+pub trait Instance: crate::Sealed + rcc::Enable + rcc::Reset + General + CPin<0> + CPin<1> {
+    fn setup_qei(&mut self);
+
+    fn read_direction(&self) -> bool;
+}
+
+macro_rules! hal {
+    ($TIM:ty) => {
+        impl Instance for $TIM {
+            fn setup_qei(&mut self) {
+                // Configure TxC1 and TxC2 as captures
+                #[cfg(not(feature = "gpio-f410"))]
+                self.ccmr1_input().write(|w| w.cc1s().ti1().cc2s().ti2());
+                #[cfg(feature = "gpio-f410")]
+                self.ccmr1_input()
+                    .write(|w| unsafe { w.cc1s().bits(0b01).cc2s().bits(0b01) });
+                // enable and configure to capture on rising edge
+                self.ccer.write(|w| {
+                    w.cc1e().set_bit().cc1p().clear_bit();
+                    w.cc2e().set_bit().cc2p().clear_bit()
+                });
+                self.smcr.write(|w| w.sms().encoder_mode_3());
+                self.set_auto_reload(<$TIM as General>::Width::MAX as u32)
+                    .unwrap();
+                self.cr1.write(|w| w.cen().set_bit());
+            }
+
+            fn read_direction(&self) -> bool {
+                self.cr1.read().dir().bit_is_clear()
+            }
+        }
+    };
+}
+
+#[cfg(feature = "tim1")]
+hal! { pac::TIM1 }
+#[cfg(feature = "tim2")]
+hal! { pac::TIM2 }
+#[cfg(feature = "tim3")]
+hal! { pac::TIM3 }
+#[cfg(feature = "tim4")]
+hal! { pac::TIM4 }
+#[cfg(feature = "tim5")]
+hal! { pac::TIM5 }
+#[cfg(feature = "tim8")]
+hal! { pac::TIM8 }