Allow GPIO block splitting without reset.

Adds method `split_without_reset` to split a GPIO block
without resetting it via the RCC register.

Author: surban

src/gpio.rs

@@ -119,8 +119,13 @@ pub trait GpioExt {
     /// The to split the GPIO into
     type Parts;
 
-    /// Splits the GPIO block into independent pins and registers
+    /// Splits the GPIO block into independent pins and registers.
+    ///
+    /// This resets the state of the GPIO block.
     fn split(self) -> Self::Parts;
+
+    /// Splits the GPIO block into independent pins and registers without resetting its state.
+    fn split_without_reset(self) -> Self::Parts;
 }
 
 /// Marker trait for active states.
@@ -391,6 +396,19 @@ macro_rules! gpio {
                         )+
                     }
                 }
+
+                fn split_without_reset(self) -> Parts {
+                    let rcc = unsafe { &(*RCC::ptr()) };
+                    $GPIOX::enable(rcc);
+
+                    Parts {
+                        crl: Cr::<$port_id, false>(()),
+                        crh: Cr::<$port_id, true>(()),
+                        $(
+                            $pxi: $PXi::new(),
+                        )+
+                    }
+                }
             }
 
             impl<MODE> PartiallyErasedPin<$port_id, MODE> {