From 5cf3fbece4adcf8d1d4475593ab9d6caf1e30f62 Mon Sep 17 00:00:00 2001
From: Vincent Stakenburg <v.stakenburg@cosinuss.nl>
Date: Fri, 10 Jun 2022 16:10:54 +0200
Subject: [PATCH] initial independent watchdog implementation

---
 embassy-stm32/src/lib.rs     |  3 +++
 embassy-stm32/src/wdg/mod.rs | 52 ++++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)
 create mode 100644 embassy-stm32/src/wdg/mod.rs

diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 717ebb95e..7be0c77ea 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -55,6 +55,9 @@ pub mod usb;
 #[cfg(any(otgfs, otghs))]
 pub mod usb_otg;
 
+#[cfg(iwdg)]
+pub mod wdg;
+
 #[cfg(feature = "subghz")]
 pub mod subghz;
 
diff --git a/embassy-stm32/src/wdg/mod.rs b/embassy-stm32/src/wdg/mod.rs
new file mode 100644
index 000000000..4353c403b
--- /dev/null
+++ b/embassy-stm32/src/wdg/mod.rs
@@ -0,0 +1,52 @@
+use core::marker::PhantomData;
+
+use embassy::util::Unborrow;
+use embassy_hal_common::unborrow;
+
+use stm32_metapac::iwdg::vals::Key;
+
+pub use stm32_metapac::iwdg::vals::Pr as Prescaler;
+
+pub struct IndependentWatchdog<'d, T: Instance> {
+    wdg: PhantomData<&'d mut T>,
+}
+
+impl<'d, T: Instance> IndependentWatchdog<'d, T> {
+    pub fn new(_instance: impl Unborrow<Target = T>, presc: Prescaler) -> Self {
+        unborrow!(_instance);
+
+        let wdg = T::regs();
+        unsafe {
+            wdg.kr().write(|w| w.set_key(Key::ENABLE));
+            wdg.pr().write(|w| w.set_pr(presc));
+        }
+
+        IndependentWatchdog {
+            wdg: PhantomData::default(),
+        }
+    }
+
+    pub unsafe fn unleash(&mut self) {
+        T::regs().kr().write(|w| w.set_key(Key::START));
+    }
+
+    pub unsafe fn feed(&mut self) {
+        T::regs().kr().write(|w| w.set_key(Key::RESET));
+    }
+}
+
+mod sealed {
+    pub trait Instance {
+        fn regs() -> crate::pac::iwdg::Iwdg;
+    }
+}
+
+pub trait Instance: sealed::Instance {}
+
+impl sealed::Instance for crate::peripherals::IWDG {
+    fn regs() -> crate::pac::iwdg::Iwdg {
+        crate::pac::IWDG
+    }
+}
+
+impl Instance for crate::peripherals::IWDG {}