ValleyView puts some display related registers like the PLL controls and dividers behind the DPIO bus. Add simple indirect register access routines to get to those registers. v2: move new wait_for macro to intel_drv.h (Ben) fix DPIO_PKT double write (Ben) add debugfs file Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>