3 files changed, 222 insertions, 0 deletions

diff --git a/embassy-nrf/src/gpiote.rs b/embassy-nrf/src/gpiote.rs
new file mode 100644
index 000000000..e6479b5e8
--- /dev/null
+++ b/embassy-nrf/src/gpiote.rs
@@ -0,0 +1,136 @@
+use core::cell::Cell;
+use core::pin::Pin;
+use core::ptr;
+use defmt::trace;
+use embassy::util::Signal;
+use nrf52840_hal::gpio::{Floating, Input, Pin as GpioPin, Port};
+
+use crate::interrupt;
+use crate::pac::GPIOTE;
+
+pub struct Gpiote {
+    inner: GPIOTE,
+    free_channels: Cell<u8>, // 0 = used, 1 = free. 8 bits for 8 channelself.
+    signals: [Signal<()>; 8],
+}
+
+static mut INSTANCE: *const Gpiote = ptr::null_mut();
+
+pub enum EventPolarity {
+    None,
+    HiToLo,
+    LoToHi,
+    Toggle,
+}
+
+#[derive(defmt::Format)]
+pub enum NewChannelError {
+    NoFreeChannels,
+}
+
+impl Gpiote {
+    pub fn new(gpiote: GPIOTE) -> Self {
+        let signal: Signal<()> = Signal::new();
+
+        interrupt::unpend(interrupt::GPIOTE);
+        interrupt::enable(interrupt::GPIOTE);
+
+        Self {
+            inner: gpiote,
+            free_channels: Cell::new(0xFF), // all 8 channels free
+            signals: [
+                Signal::new(),
+                Signal::new(),
+                Signal::new(),
+                Signal::new(),
+                Signal::new(),
+                Signal::new(),
+                Signal::new(),
+                Signal::new(),
+            ],
+        }
+    }
+
+    pub fn new_input_channel<T>(
+        &self,
+        pin: GpioPin<Input<T>>,
+        trigger_mode: EventPolarity,
+    ) -> Result<Channel<'_>, NewChannelError> {
+        interrupt::free(|_| {
+            unsafe { INSTANCE = self };
+
+            let chs = self.free_channels.get();
+            let index = chs.trailing_zeros() as usize;
+            if index == 8 {
+                return Err(NewChannelError::NoFreeChannels);
+            }
+            self.free_channels.set(chs & !(1 << index));
+
+            trace!("allocated ch {:u8}", index as u8);
+
+            self.inner.config[index].write(|w| {
+                match trigger_mode {
+                    EventPolarity::HiToLo => w.mode().event().polarity().hi_to_lo(),
+                    EventPolarity::LoToHi => w.mode().event().polarity().lo_to_hi(),
+                    EventPolarity::None => w.mode().event().polarity().none(),
+                    EventPolarity::Toggle => w.mode().event().polarity().toggle(),
+                };
+                w.port().bit(match pin.port() {
+                    Port::Port0 => false,
+                    Port::Port1 => true,
+                });
+                unsafe { w.psel().bits(pin.pin()) }
+            });
+
+            // Enable interrupt
+            self.inner.intenset.write(|w| unsafe { w.bits(1 << index) });
+
+            Ok(Channel {
+                gpiote: self,
+                index: index as u8,
+            })
+        })
+    }
+}
+
+pub struct Channel<'a> {
+    gpiote: &'a Gpiote,
+    index: u8,
+}
+
+impl<'a> Drop for Channel<'a> {
+    fn drop(&mut self) {
+        let g = unsafe { Pin::new_unchecked(self.gpiote) };
+
+        interrupt::free(|_| {
+            self.gpiote.inner.config[self.index as usize].write(|w| w.mode().disabled());
+            self.gpiote
+                .inner
+                .intenclr
+                .write(|w| unsafe { w.bits(1 << self.index) });
+
+            self.gpiote
+                .free_channels
+                .set(self.gpiote.free_channels.get() | 1 << self.index);
+            trace!("freed ch {:u8}", self.index);
+        })
+    }
+}
+
+impl<'a> Channel<'a> {
+    pub async fn wait(&self) -> () {
+        self.gpiote.signals[self.index as usize].wait().await;
+    }
+}
+
+#[interrupt]
+unsafe fn GPIOTE() {
+    let s = &(*INSTANCE);
+
+    for i in 0..8 {
+        if s.inner.events_in[i].read().bits() != 0 {
+            s.inner.events_in[i].write(|w| w);
+            s.signals[i].signal(());
+        }
+    }
+}
diff --git a/embassy-nrf/src/lib.rs b/embassy-nrf/src/lib.rs
index f1ce0cbf9..edc2778b8 100644
--- a/embassy-nrf/src/lib.rs
+++ b/embassy-nrf/src/lib.rs
@@ -37,7 +37,9 @@ pub use nrf52833_pac as pac;
 #[cfg(feature = "nrf52840")]
 pub use nrf52840_pac as pac;
 
+pub mod gpiote;
 pub mod interrupt;
 pub mod qspi;
 pub mod uarte;
+
 pub use cortex_m_rt::interrupt;
diff --git a/examples/src/bin/gpiote.rs b/examples/src/bin/gpiote.rs
new file mode 100644
index 000000000..f55b0386d
--- /dev/null
+++ b/examples/src/bin/gpiote.rs
@@ -0,0 +1,84 @@
+#![no_std]
+#![no_main]
+#![feature(type_alias_impl_trait)]
+
+#[path = "../example_common.rs"]
+mod example_common;
+use example_common::*;
+
+use core::pin::Pin;
+use cortex_m_rt::entry;
+use embassy::io::{AsyncBufRead, AsyncBufReadExt, AsyncWrite, AsyncWriteExt};
+use embassy_nrf::gpiote;
+use futures::pin_mut;
+use nrf52840_hal::gpio;
+
+#[static_executor::task]
+async fn run() {
+    let p = embassy_nrf::pac::Peripherals::take().dewrap();
+    let port0 = gpio::p0::Parts::new(p.P0);
+
+    let g = gpiote::Gpiote::new(p.GPIOTE);
+
+    info!("Starting!");
+
+    let pin1 = port0.p0_11.into_pullup_input().degrade();
+    let button1 = async {
+        let ch = g
+            .new_input_channel(pin1, gpiote::EventPolarity::HiToLo)
+            .dewrap();
+
+        loop {
+            ch.wait().await;
+            info!("Button 1 pressed")
+        }
+    };
+
+    let pin2 = port0.p0_12.into_pullup_input().degrade();
+    let button2 = async {
+        let ch = g
+            .new_input_channel(pin2, gpiote::EventPolarity::LoToHi)
+            .dewrap();
+
+        loop {
+            ch.wait().await;
+            info!("Button 2 released")
+        }
+    };
+
+    let pin3 = port0.p0_24.into_pullup_input().degrade();
+    let button3 = async {
+        let ch = g
+            .new_input_channel(pin3, gpiote::EventPolarity::Toggle)
+            .dewrap();
+
+        loop {
+            ch.wait().await;
+            info!("Button 3 toggled")
+        }
+    };
+
+    let pin4 = port0.p0_25.into_pullup_input().degrade();
+    let button4 = async {
+        let ch = g
+            .new_input_channel(pin4, gpiote::EventPolarity::Toggle)
+            .dewrap();
+
+        loop {
+            ch.wait().await;
+            info!("Button 4 toggled")
+        }
+    };
+
+    futures::join!(button1, button2, button3, button4);
+}
+
+#[entry]
+fn main() -> ! {
+    info!("Hello World!");
+
+    unsafe {
+        run.spawn().dewrap();
+        static_executor::run();
+    }
+}