4 files changed, 97 insertions, 46 deletions

diff --git a/embassy-stm32/src/spi/mod.rs b/embassy-stm32/src/spi/mod.rs
index 492fc41c6..e881a5235 100644
--- a/embassy-stm32/src/spi/mod.rs
+++ b/embassy-stm32/src/spi/mod.rs
@@ -8,7 +8,7 @@ mod _version;
 use crate::{dma, peripherals, rcc::RccPeripheral};
 pub use _version::*;
 
-use crate::gpio::Pin;
+use crate::gpio::OptionalPin;
 
 #[derive(Debug)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
@@ -53,15 +53,15 @@ pub(crate) mod sealed {
         fn regs() -> &'static crate::pac::spi::Spi;
     }
 
-    pub trait SckPin<T: Instance>: Pin {
+    pub trait SckPin<T: Instance>: OptionalPin {
         fn af_num(&self) -> u8;
     }
 
-    pub trait MosiPin<T: Instance>: Pin {
+    pub trait MosiPin<T: Instance>: OptionalPin {
         fn af_num(&self) -> u8;
     }
 
-    pub trait MisoPin<T: Instance>: Pin {
+    pub trait MisoPin<T: Instance>: OptionalPin {
         fn af_num(&self) -> u8;
     }
 
diff --git a/embassy-stm32/src/spi/v1.rs b/embassy-stm32/src/spi/v1.rs
index 560d99a2f..6f8f8afb6 100644
--- a/embassy-stm32/src/spi/v1.rs
+++ b/embassy-stm32/src/spi/v1.rs
@@ -6,9 +6,10 @@ use crate::gpio::{
         AFType::{OutputOpenDrain, OutputPushPull},
         Pin,
     },
-    AnyPin,
+    AnyPin, NoPin,
 };
 use crate::pac::spi;
+use crate::peripherals;
 use crate::spi::{
     ByteOrder, Config, Error, Instance, MisoPin, MosiPin, RxDmaChannel, SckPin, TxDmaChannel,
     WordSize,
@@ -20,6 +21,7 @@ use core::ptr;
 use embassy::util::Unborrow;
 use embassy_hal_common::unborrow;
 use embassy_traits::spi as traits;
+pub use embedded_hal::blocking;
 pub use embedded_hal::spi::{Mode, Phase, Polarity, MODE_0, MODE_1, MODE_2, MODE_3};
 use futures::future::join3;
 
@@ -32,10 +34,29 @@ impl WordSize {
     }
 }
 
+macro_rules! impl_nopin {
+    ($inst:ident, $signal:ident) => {
+        impl $signal<peripherals::$inst> for NoPin {}
+
+        impl super::sealed::$signal<peripherals::$inst> for NoPin {
+            fn af_num(&self) -> u8 {
+                0
+            }
+        }
+    };
+}
+crate::pac::peripherals!(
+    (spi, $inst:ident) => {
+        impl_nopin!($inst, SckPin);
+        impl_nopin!($inst, MosiPin);
+        impl_nopin!($inst, MisoPin);
+    };
+);
+
 pub struct Spi<'d, T: Instance, Tx, Rx> {
-    sck: AnyPin,
-    mosi: AnyPin,
-    miso: AnyPin,
+    sck: Option<AnyPin>,
+    mosi: Option<AnyPin>,
+    miso: Option<AnyPin>,
     txdma: Tx,
     rxdma: Rx,
     current_word_size: WordSize,
@@ -58,16 +79,19 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
     {
         unborrow!(sck, mosi, miso, txdma, rxdma);
 
+        let sck_af = sck.af_num();
+        let mosi_af = mosi.af_num();
+        let miso_af = miso.af_num();
+        let sck = sck.degrade_optional();
+        let mosi = mosi.degrade_optional();
+        let miso = miso.degrade_optional();
+
         unsafe {
-            sck.set_as_af(sck.af_num(), OutputPushPull);
-            mosi.set_as_af(mosi.af_num(), OutputPushPull);
-            miso.set_as_af(miso.af_num(), OutputOpenDrain);
+            sck.as_ref().map(|x| x.set_as_af(sck_af, OutputPushPull));
+            mosi.as_ref().map(|x| x.set_as_af(mosi_af, OutputPushPull));
+            miso.as_ref().map(|x| x.set_as_af(miso_af, OutputOpenDrain));
         }
 
-        let sck = sck.degrade();
-        let mosi = mosi.degrade();
-        let miso = miso.degrade();
-
         unsafe {
             T::regs().cr2().modify(|w| {
                 w.set_ssoe(false);
@@ -103,6 +127,9 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
                 w.set_ssm(true);
                 w.set_crcen(false);
                 w.set_bidimode(spi::vals::Bidimode::UNIDIRECTIONAL);
+                if mosi.is_none() {
+                    w.set_rxonly(spi::vals::Rxonly::OUTPUTDISABLED);
+                }
                 w.set_dff(WordSize::EightBit.dff())
             });
         }
@@ -294,9 +321,9 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
 impl<'d, T: Instance, Tx, Rx> Drop for Spi<'d, T, Tx, Rx> {
     fn drop(&mut self) {
         unsafe {
-            self.sck.set_as_analog();
-            self.mosi.set_as_analog();
-            self.miso.set_as_analog();
+            self.sck.as_ref().map(|x| x.set_as_analog());
+            self.mosi.as_ref().map(|x| x.set_as_analog());
+            self.miso.as_ref().map(|x| x.set_as_analog());
         }
     }
 }
diff --git a/embassy-stm32/src/spi/v2.rs b/embassy-stm32/src/spi/v2.rs
index 9df71ef25..cb871a9a0 100644
--- a/embassy-stm32/src/spi/v2.rs
+++ b/embassy-stm32/src/spi/v2.rs
@@ -36,9 +36,9 @@ impl WordSize {
 }
 
 pub struct Spi<'d, T: Instance, Tx, Rx> {
-    sck: AnyPin,
-    mosi: AnyPin,
-    miso: AnyPin,
+    sck: Option<AnyPin>,
+    mosi: Option<AnyPin>,
+    miso: Option<AnyPin>,
     txdma: Tx,
     rxdma: Rx,
     phantom: PhantomData<&'d mut T>,
@@ -60,16 +60,22 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
     {
         unborrow!(sck, mosi, miso, txdma, rxdma);
 
+        let sck_af = sck.af_num();
+        let mosi_af = mosi.af_num();
+        let miso_af = miso.af_num();
+        let sck = sck.degrade_optional();
+        let mosi = mosi.degrade_optional();
+        let miso = miso.degrade_optional();
+
         unsafe {
-            Self::configure_pin(sck.block(), sck.pin() as _, sck.af_num());
-            Self::configure_pin(mosi.block(), mosi.pin() as _, mosi.af_num());
-            Self::configure_pin(miso.block(), miso.pin() as _, miso.af_num());
+            sck.as_ref()
+                .map(|x| Self::configure_pin(x.block(), x.pin() as _, sck_af));
+            sck.as_ref()
+                .map(|x| Self::configure_pin(x.block(), x.pin() as _, mosi_af));
+            sck.as_ref()
+                .map(|x| Self::configure_pin(x.block(), x.pin() as _, miso_af));
         }
 
-        let sck = sck.degrade();
-        let mosi = mosi.degrade();
-        let miso = miso.degrade();
-
         let pclk = T::frequency();
         let freq = freq.into();
         let br = Self::compute_baud_rate(pclk, freq);
@@ -307,9 +313,15 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
 impl<'d, T: Instance, Tx, Rx> Drop for Spi<'d, T, Tx, Rx> {
     fn drop(&mut self) {
         unsafe {
-            Self::unconfigure_pin(self.sck.block(), self.sck.pin() as _);
-            Self::unconfigure_pin(self.mosi.block(), self.mosi.pin() as _);
-            Self::unconfigure_pin(self.miso.block(), self.miso.pin() as _);
+            self.sck
+                .as_ref()
+                .map(|x| Self::unconfigure_pin(x.block(), x.pin() as _));
+            self.mosi
+                .as_ref()
+                .map(|x| Self::unconfigure_pin(x.block(), x.pin() as _));
+            self.miso
+                .as_ref()
+                .map(|x| Self::unconfigure_pin(x.block(), x.pin() as _));
         }
     }
 }
diff --git a/embassy-stm32/src/spi/v3.rs b/embassy-stm32/src/spi/v3.rs
index b0e57254e..ef0f123f1 100644
--- a/embassy-stm32/src/spi/v3.rs
+++ b/embassy-stm32/src/spi/v3.rs
@@ -38,9 +38,9 @@ impl WordSize {
 
 #[allow(unused)]
 pub struct Spi<'d, T: Instance, Tx = NoDma, Rx = NoDma> {
-    sck: AnyPin,
-    mosi: AnyPin,
-    miso: AnyPin,
+    sck: Option<AnyPin>,
+    mosi: Option<AnyPin>,
+    miso: Option<AnyPin>,
     txdma: Tx,
     rxdma: Rx,
     phantom: PhantomData<&'d mut T>,
@@ -62,18 +62,24 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
     {
         unborrow!(sck, mosi, miso, txdma, rxdma);
 
+        let sck_af = sck.af_num();
+        let mosi_af = mosi.af_num();
+        let miso_af = miso.af_num();
+        let sck = sck.degrade_optional();
+        let mosi = mosi.degrade_optional();
+        let miso = miso.degrade_optional();
+
         unsafe {
-            Self::configure_pin(sck.block(), sck.pin() as _, sck.af_num());
-            //sck.block().otyper().modify(|w| w.set_ot(sck.pin() as _, crate::pac::gpio::vals::Ot::PUSHPULL));
-            Self::configure_pin(mosi.block(), mosi.pin() as _, mosi.af_num());
-            //mosi.block().otyper().modify(|w| w.set_ot(mosi.pin() as _, crate::pac::gpio::vals::Ot::PUSHPULL));
-            Self::configure_pin(miso.block(), miso.pin() as _, miso.af_num());
+            sck.as_ref()
+                .map(|x| Self::configure_pin(x.block(), x.pin() as _, sck_af));
+            //sck.block().otyper().modify(|w| w.set_ot(Pin::pin(sck) as _, crate::pac::gpio::vals::Ot::PUSHPULL));
+            sck.as_ref()
+                .map(|x| Self::configure_pin(x.block(), x.pin() as _, mosi_af));
+            //mosi.block().otyper().modify(|w| w.set_ot(Pin::pin(mosi) as _, crate::pac::gpio::vals::Ot::PUSHPULL));
+            sck.as_ref()
+                .map(|x| Self::configure_pin(x.block(), x.pin() as _, miso_af));
         }
 
-        let sck = sck.degrade();
-        let mosi = mosi.degrade();
-        let miso = miso.degrade();
-
         let pclk = T::frequency();
         let br = Self::compute_baud_rate(pclk, freq.into());
         unsafe {
@@ -340,9 +346,15 @@ impl<'d, T: Instance, Tx, Rx> Spi<'d, T, Tx, Rx> {
 impl<'d, T: Instance, Tx, Rx> Drop for Spi<'d, T, Tx, Rx> {
     fn drop(&mut self) {
         unsafe {
-            Self::unconfigure_pin(self.sck.block(), self.sck.pin() as _);
-            Self::unconfigure_pin(self.mosi.block(), self.mosi.pin() as _);
-            Self::unconfigure_pin(self.miso.block(), self.miso.pin() as _);
+            self.sck
+                .as_ref()
+                .map(|x| Self::unconfigure_pin(x.block(), x.pin() as _));
+            self.mosi
+                .as_ref()
+                .map(|x| Self::unconfigure_pin(x.block(), x.pin() as _));
+            self.miso
+                .as_ref()
+                .map(|x| Self::unconfigure_pin(x.block(), x.pin() as _));
         }
     }
 }