This has been copied from Linux source at revision 786f02b719f. Signed-off-by: Otavio Salvador <otavio@ossystems.com.br> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Marek Vasut <marex@denx.de> Cc: Stefano Babic <sbabic@denx.de>