I can also add this new property (support for it already in linux-next):

On 10/11/2011 07:13 PM, Nicolas Ferre :

Generic bindings for RS485 feature included in some UARTs.
Those bindings have to be used withing an UART device tree node.
Documentation updated to link to the bindings definition.

[..]

+Optional properties:
+- linux,rs485-enabled-at-boot-time: empty property telling to enable the rs485
+  feature at boot time. It can be disabled later with proper ioctl.

+- linux,rs485-rx-during-tx: empty property that enable the receiving of data
+  even whilst sending data.

+- linux,rs485-rts-delay: prop-encoded-array <a b> where:

[..]

Best regards,
-- 
Nicolas Ferre