From a08d7814420ed575ead6744f4254bfbb431bbc27 Mon Sep 17 00:00:00 2001
From: Richard Dodd <richard.o.dodd@gmail.com>
Date: Wed, 24 Mar 2021 18:31:11 +0100
Subject: [PATCH] nrf/gpio: allow borrowed pins.

---
 embassy-nrf-examples/src/bin/gpiote_port.rs |  2 +-
 embassy-nrf/src/gpio.rs                     | 44 +++++++++++++++------
 embassy-nrf/src/gpiote.rs                   | 19 ++++-----
 3 files changed, 42 insertions(+), 23 deletions(-)

diff --git a/embassy-nrf-examples/src/bin/gpiote_port.rs b/embassy-nrf-examples/src/bin/gpiote_port.rs
index 593261ae..556a199f 100644
--- a/embassy-nrf-examples/src/bin/gpiote_port.rs
+++ b/embassy-nrf-examples/src/bin/gpiote_port.rs
@@ -19,7 +19,7 @@ use embassy_nrf::interrupt;
 use embassy_nrf::Peripherals;
 use example_common::*;
 
-async fn button(n: usize, mut pin: PortInput<AnyPin>) {
+async fn button(n: usize, mut pin: PortInput<'static, AnyPin>) {
     loop {
         Pin::new(&mut pin).wait_for_low().await;
         info!("Button {:?} pressed!", n);
diff --git a/embassy-nrf/src/gpio.rs b/embassy-nrf/src/gpio.rs
index d48ad3d0..0d566ff3 100644
--- a/embassy-nrf/src/gpio.rs
+++ b/embassy-nrf/src/gpio.rs
@@ -1,7 +1,9 @@
 use core::convert::Infallible;
 use core::hint::unreachable_unchecked;
+use core::marker::PhantomData;
 
 use embassy::util::PeripheralBorrow;
+use embassy_extras::unborrow;
 use embedded_hal::digital::v2::{InputPin, OutputPin, StatefulOutputPin};
 use gpio::pin_cnf::DRIVE_A;
 
@@ -30,12 +32,15 @@ pub enum Pull {
 }
 
 /// GPIO input driver.
-pub struct Input<T: Pin> {
+pub struct Input<'d, T: Pin> {
     pub(crate) pin: T,
+    phantom: PhantomData<&'d mut T>,
 }
 
-impl<T: Pin> Input<T> {
-    pub fn new(pin: T, pull: Pull) -> Self {
+impl<'d, T: Pin> Input<'d, T> {
+    pub fn new(pin: impl PeripheralBorrow<Target = T> + 'd, pull: Pull) -> Self {
+        unborrow!(pin);
+
         pin.conf().write(|w| {
             w.dir().input();
             w.input().connect();
@@ -55,17 +60,20 @@ impl<T: Pin> Input<T> {
             w
         });
 
-        Self { pin }
+        Self {
+            pin,
+            phantom: PhantomData,
+        }
     }
 }
 
-impl<T: Pin> Drop for Input<T> {
+impl<'d, T: Pin> Drop for Input<'d, T> {
     fn drop(&mut self) {
         self.pin.conf().reset();
     }
 }
 
-impl<T: Pin> InputPin for Input<T> {
+impl<'d, T: Pin> InputPin for Input<'d, T> {
     type Error = Infallible;
 
     fn is_high(&self) -> Result<bool, Self::Error> {
@@ -108,12 +116,19 @@ pub enum OutputDrive {
 }
 
 /// GPIO output driver.
-pub struct Output<T: Pin> {
+pub struct Output<'d, T: Pin> {
     pin: T,
+    phantom: PhantomData<&'d mut T>,
 }
 
-impl<T: Pin> Output<T> {
-    pub fn new(pin: T, initial_output: Level, drive: OutputDrive) -> Self {
+impl<'d, T: Pin> Output<'d, T> {
+    pub fn new(
+        pin: impl PeripheralBorrow<Target = T> + 'd,
+        initial_output: Level,
+        drive: OutputDrive,
+    ) -> Self {
+        unborrow!(pin);
+
         match initial_output {
             Level::High => pin.set_high(),
             Level::Low => pin.set_low(),
@@ -139,17 +154,20 @@ impl<T: Pin> Output<T> {
             w
         });
 
-        Self { pin }
+        Self {
+            pin,
+            phantom: PhantomData,
+        }
     }
 }
 
-impl<T: Pin> Drop for Output<T> {
+impl<'d, T: Pin> Drop for Output<'d, T> {
     fn drop(&mut self) {
         self.pin.conf().reset();
     }
 }
 
-impl<T: Pin> OutputPin for Output<T> {
+impl<'d, T: Pin> OutputPin for Output<'d, T> {
     type Error = Infallible;
 
     /// Set the output as high.
@@ -175,7 +193,7 @@ impl<T: Pin> OutputPin for Output<T> {
     }
 }
 
-impl<T: Pin> StatefulOutputPin for Output<T> {
+impl<'d, T: Pin> StatefulOutputPin for Output<'d, T> {
     /// Is the output pin set as high?
     fn is_set_high(&self) -> Result<bool, Self::Error> {
         self.is_set_low().map(|v| !v)
diff --git a/embassy-nrf/src/gpiote.rs b/embassy-nrf/src/gpiote.rs
index dc96a7eb..9a7642c5 100644
--- a/embassy-nrf/src/gpiote.rs
+++ b/embassy-nrf/src/gpiote.rs
@@ -9,7 +9,7 @@ use core::ptr;
 use core::task::{Context, Poll};
 use embassy::interrupt::InterruptExt;
 use embassy::traits::gpio::{WaitForHigh, WaitForLow};
-use embassy::util::{AtomicWakerRegistration, Signal};
+use embassy::util::{AtomicWakerRegistration, PeripheralBorrow, Signal};
 use embedded_hal::digital::v2::{InputPin, OutputPin, StatefulOutputPin};
 
 use crate::gpio::sealed::Pin as _;
@@ -338,18 +338,19 @@ impl<C: ChannelID, T> OutputChannel<C, T> {
  */
 
 /// GPIO input driver with support
-pub struct PortInput<T: GpioPin> {
-    pin: Input<T>,
+pub struct PortInput<'d, T: GpioPin> {
+    pin: Input<'d, T>,
 }
-impl<T: GpioPin> Unpin for PortInput<T> {}
 
-impl<T: GpioPin> PortInput<T> {
-    pub fn new(_init: Initialized, pin: Input<T>) -> Self {
+impl<'d, T: GpioPin> Unpin for PortInput<'d, T> {}
+
+impl<'d, T: GpioPin> PortInput<'d, T> {
+    pub fn new(_init: Initialized, pin: Input<'d, T>) -> Self {
         Self { pin }
     }
 }
 
-impl<T: GpioPin> InputPin for PortInput<T> {
+impl<'d, T: GpioPin> InputPin for PortInput<'d, T> {
     type Error = Infallible;
 
     fn is_high(&self) -> Result<bool, Self::Error> {
@@ -361,7 +362,7 @@ impl<T: GpioPin> InputPin for PortInput<T> {
     }
 }
 
-impl<T: GpioPin> WaitForHigh for PortInput<T> {
+impl<'d, T: GpioPin> WaitForHigh for PortInput<'d, T> {
     type Future<'a> = PortInputFuture<'a>;
 
     fn wait_for_high<'a>(self: Pin<&'a mut Self>) -> Self::Future<'a> {
@@ -374,7 +375,7 @@ impl<T: GpioPin> WaitForHigh for PortInput<T> {
     }
 }
 
-impl<T: GpioPin> WaitForLow for PortInput<T> {
+impl<'d, T: GpioPin> WaitForLow for PortInput<'d, T> {
     type Future<'a> = PortInputFuture<'a>;
 
     fn wait_for_low<'a>(self: Pin<&'a mut Self>) -> Self::Future<'a> {