Add documentation

rp2040-hal/CHANGELOG.md

@@ -18,6 +18,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   more slowly than on the Raspberry Pico.
 - Some reorganization of ADC code, making sure that AdcPin can only
   be created for pins that can actually be used as ADC channels.
+- Breaking change: Clear the input-enable flag of all pins on bank 0 in `Pins::new`.
+  They will automatically be enabled when setting a pin function, so most users
+  won't be affected by that change. Notable exception: If you rely on the fact that
+  PIO can read all pins as input even if the pin is not configured to the PIO function,
+  you may need to set the input-enable flag manually. - #755 @jannic
 
 ## [0.9.1]
 

rp2040-hal/src/gpio/mod.rs

@@ -1049,6 +1049,8 @@ macro_rules! gpio {
 
                 impl Pins {
                     /// Take ownership of the PAC peripherals and SIO slice and split it into discrete [`Pin`]s
+                    ///
+                    /// This clears the input-enable flag for all Bank0 pads.
                     pub fn new(io : [<IO_ $bank:upper>], pads: [<PADS_ $bank:upper>], sio: [<SioGpio $bank>], reset : &mut $crate::pac::RESETS) -> Self {
                         use $crate::resets::SubsystemReset;
                         pads.reset_bring_down(reset);