mod.rs

use self::arm1176jzf_s::gpio::pin_mode::OUTPUT; 
// Compilation error: cannot import from a trait or type implementation

pub mod arm1176jzf_s; 
// Defined with submodules in separate file

pub fn init() {
  let p : Pin = arm1176jzf_s::gpio::Pin::get(16);
  p.setMode(OUTPUT);
  // setMode has a single parameter of type arm1176jzf_s::gpio::pin_mode; OUTPUT is a variant thereof
  // Even with "use" above removed, this gives an error- rustc doesn't recognize the name OUTPUT
  
  p.write(p, false);
}            

Resolution: OUTPUT is in the gpio namespace, not a pin_mode namespace. So use self::arm1176jzf_s::gpio lets us then refer to gpio::OUTPUT unambiguously.