gpio: Add initializer based on pin and port numbers

Follow-up-for: RIOT-OS/rust-riot-sys#17

src/gpio.rs

@@ -85,14 +85,16 @@ impl GPIO {
  }
  }
 
- // using a generic GPIO_PIN is probably best done by making GPIO_INIT a static inline (given
- // it's already fixed to types at tests/periph_gpio/main.c)
- // /// Create a GPIO out of thin air
- // #[cfg(riot_module_nrf5x_common_periph)]
- // pub unsafe fn new(port: u8, pin: u8) -> Self {
- // // EXPANDED cpu/nrf5x_common/include/periph_cpu_common.h:50
- // GPIO(((port << 5) | pin).into())
- // }
+ /// Create a GPIO from its port and pin numbers
+ ///
+ /// ```
+ /// let pin_c8 = GPIO::from_port_and_pin(3, 8);
+ /// ```
+ ///
+ /// See [from_c] for safety constraints.
+ pub fn from_port_and_pin(port: usize, pin: usize) -> Option<Self> {
+ Self::from_c(unsafe { riot_sys::macro_GPIO_PIN(port, pin) })
+ }
 
  pub fn configure_as_output(
  self,