CPM2 mii-bitbang: Allowing mdio on port pins other than port C

Mark Ware mark.ware at senetas.com
Mon Jun 16 16:19:32 EST 2008


Hello,

I am preparing a board port (from 2.4.18!) for a proprietary board which
has it's mdio on a different port than mdc.  The current mii-bitbang
driver in fs_enet assumes both pins are connected to port C.  I have
created a fairly simple patch to make this more flexible, but I'm new to
device trees and am unsure how best to describe the situation in the
dts.

The current mdio node for CPM2 looks something like:

mdio at 10d40 {
  device_type = "mdio";
  compatible = "fsl,cpm2-mdio-bitbang";
  #address-cells = <1>;
  #size-cells = <0>
  reg = <0x10d40 0x14>;
  fsl,mdio-pin = <12>;
  fsl,mdc-pin = <15>;
}

I have made mdio work on our board by adding a second reg range and
using the first one for mdc and the second one for mdio: 

  reg = <0x10d40 0x14 0x10d60 0x14>;  // mdc=port D, mdio=port A
  fsl,mdio-pin = <12>;    		  // PD12
  fsl,mdc-pin = <15>;     		  // PC15

The code remains backwards compatible, in that if only one reg range is
present it is used for both.

Is this a valid (and acceptable) way to extend the reg property?  Is
their a cleaner way I should look at?

Regards,
Mark Ware
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