This driver is also used for Allwinner SoCs I2C controllers.

Ported from linux-3.15.

The most notable barebox driver version changes:

  * drop platform device stuff;
  * drop "allwinner,sun*" stuff;
  * drop message offloading support;
  * add reg-io-width devicetree parameter to use driver
    with byte-oriented controller versions.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Acked-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
On Armada XP:
Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>