Remove unnecessary runtime state from pin types

Also makes required fields private, replacing them with getters.

Fixes #46

Author: jonas-schievink

examples/button_irq.rs

@@ -46,7 +46,7 @@ fn main() -> ! {
 
     // Configure the external interrupt on the falling edge for the pin 0.
     let exti = dp.EXTI;
-    exti.listen(&mut syscfg, button.port, button.i, TriggerEdge::Falling);
+    exti.listen(&mut syscfg, button.port(), button.pin_number(), TriggerEdge::Falling);
 
     // Store the external interrupt and LED in mutex reffcells to make them
     // available from the interrupt.

examples/button_irq_rtfm.rs

@@ -35,7 +35,7 @@ const APP: () = {
 
         // Configure the external interrupt on the falling edge for the pin 0.
         let exti = device.EXTI;
-        exti.listen(&mut syscfg, button.port, button.i, TriggerEdge::Falling);
+        exti.listen(&mut syscfg, button.port(), button.pin_number(), TriggerEdge::Falling);
 
         // Return the initialised resources.
         init::LateResources {

examples/exti_wakeup.rs

@@ -36,14 +36,14 @@ fn main() -> ! {
 
     exti.listen(
         &mut syscfg,
-        button.port,
-        button.i,
+        button.port(),
+        button.pin_number(),
         exti::TriggerEdge::Falling,
     );
 
     loop {
         exti.wait_for_irq(
-            button.i,
+            button.pin_number(),
             pwr.stop_mode(
                 &mut scb,
                 &mut rcc,

src/gpio.rs

@@ -118,9 +118,7 @@ macro_rules! gpio {
                     Parts {
                         $(
                             $pxi: $PXi {
-                                 i: $i,
-                                port: Port::$PXx,
-                                _mode: PhantomData
+                                _mode: PhantomData,
                             },
                         )+
                     }
@@ -129,11 +127,22 @@ macro_rules! gpio {
 
             /// Partially erased pin
             pub struct $PXx<MODE> {
-                pub i: u8,
-                pub port: Port,
+                i: u8,
                 _mode: PhantomData<MODE>,
             }
 
+            impl<MODE> $PXx<MODE> {
+                /// Returns the port this pin is part of.
+                pub fn port(&self) -> Port {
+                    Port::$PXx
+                }
+
+                /// Returns this pin's number inside its port.
+                pub fn pin_number(&self) -> u8 {
+                    self.i
+                }
+            }
+
             impl<MODE> OutputPin for $PXx<Output<MODE>> {
                 type Error = super::Error;
 
@@ -198,11 +207,21 @@ macro_rules! gpio {
             $(
                 /// Pin
                 pub struct $PXi<MODE> {
-                    pub i: u8,
-                    pub port: Port,
                     _mode: PhantomData<MODE>,
                 }
 
+                impl<MODE> $PXi<MODE> {
+                    /// Returns the port this pin is part of.
+                    pub fn port(&self) -> Port {
+                        Port::$PXx
+                    }
+
+                    /// Returns this pin's number inside its port.
+                    pub fn pin_number(&self) -> u8 {
+                        $i
+                    }
+                }
+
                 impl<MODE> $PXi<MODE> {
                     /// Configures the pin to operate as a floating input pin
                     pub fn into_floating_input(
@@ -218,8 +237,6 @@ macro_rules! gpio {
                             })
                         };
                         $PXi {
-                             i: $i,
-                            port: Port::$PXx,
                             _mode: PhantomData
                         }
                     }
@@ -238,8 +255,6 @@ macro_rules! gpio {
                             })
                         };
                         $PXi {
-                             i: $i,
-                            port: Port::$PXx,
                             _mode: PhantomData
                         }
                     }
@@ -258,8 +273,6 @@ macro_rules! gpio {
                             })
                         };
                         $PXi {
-                             i: $i,
-                            port: Port::$PXx,
                             _mode: PhantomData
                         }
                     }
@@ -278,8 +291,6 @@ macro_rules! gpio {
                             });
                         }
                         $PXi {
-                             i: $i,
-                            port: Port::$PXx,
                             _mode: PhantomData
                         }
                     }
@@ -301,8 +312,6 @@ macro_rules! gpio {
                             })
                         };
                         $PXi {
-                             i: $i,
-                            port: Port::$PXx,
                             _mode: PhantomData
                         }
                     }
@@ -324,8 +333,6 @@ macro_rules! gpio {
                             })
                         };
                         $PXi {
-                             i: $i,
-                            port: Port::$PXx,
                             _mode: PhantomData
                         }
                     }
@@ -372,7 +379,6 @@ macro_rules! gpio {
                     pub fn downgrade(self) -> $PXx<Output<MODE>> {
                         $PXx {
                             i: $i,
-                            port: Port::$PXx,
                             _mode: self._mode,
                         }
                     }
@@ -433,7 +439,6 @@ macro_rules! gpio {
                     pub fn downgrade(self) -> $PXx<Input<MODE>> {
                         $PXx {
                             i: $i,
-                            port: Port::$PXx,
                             _mode: self._mode,
                         }
                     }