Re: [PATCH v4 1/4] ethernet: arc: Add support for Rockchip SoC layer device tree bindings

On Wednesday 03 September 2014 14:20:50 Heiko Stübner wrote:

quoted

One last question: is this the location given as .grf_offset the
only thing in grf that is potentially of concern to this driver?

If it is, you can change the binding to include the register number
in the syscon reference, like

      rockchip,grf = <&grf 0x154>;

and then read it from there, to simplify the code needed to get the
number from the device id.

I would disagree here 

Specific to the emac, there also exists a second register in the grf (0xa8 for 
the rk3188) that contains a field 

----
emac_newrcv_en - the selection of RMII receive selection
0: don't support the data package without header
1: support the data package without header
----

which we don't handle currently but somebody might want to in the future.
[There also is no documentation of this at all]

Ok, fair enough. If there is a chance that there would be more of these
fields that we may want to support in the future, the table approach
seems reasonable.

The main advantage of putting the register number into the syscon
reference is to support future models without driver changes, but
it's not clear if that's worth it.

	Arnd