lis302 DT binding for Nokia N900

Hi,

The lis302 has already a DT binding described in [0],
which descibes misc. hardware properties. The problem
is, that the Nokia N900 needs negative values for some
of the properties, which seem to be unsupported by DT.
The following values would be needed for the N900 (taken
from board code):

st,axis-x = <1>;  /* LIS3_DEV_X */
st,axis-y = <-2>; /* LIS3_INV_DEV_Y */
st,axis-z = <-3>; /* LIS3_INV_DEV_Z */

st,min-limit-x = <-32>;
st,min-limit-y = <3>;
st,min-limit-z = <3>;

st,max-limit-x = <-3>;
st,max-limit-y = <32>;
st,max-limit-z = <32>;

Can you please tell me how to setup the properties correctly?

[0] Documentation/devicetree/bindings/misc/lis302.txt

-- Sebastian