Re: How to encode being an I2C slave in DT?

[Rob Herring <robherring2-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

On Wed, May 6, 2015 at 11:17 AM, Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org> wrote:
>
>> The container node has a #address-cells property for this very reason. It's
>> perfectly well-defined how to split up a property containing a large number
>> of cells into separate values, by using the value of #address-cells. Plus,
>> the canonical formatting (albeit not enforced by the DT compiler) for a
>> property that contains an array of entries, each 2 cells in size, would be:
>>
>> reg = <0 0x1a>, <0 0x40>, <0 0x48>;
>>
>> rather than:
>>
>> reg = <0 0x1a 0 0x40 0 0x48>;
>>
>> ... so it's quite simple to make it very human-readable too.
>
> I give in to the flag idea. I also noticed that we'd need another flag
> anyhow to mark 10 bit addresses. I am still thinking between using two
> address-cells in that case (clean seperation between address and flags)
> or to encode the flags as MSB in the current address (all busses will
> have same address-cells and child description, less code paths and no
> overhead in dtbs).

Reading thru the thread, this seems good to me. I would go with adding
flags in the MSB of the reg cell rather than adding a cell.

Rob
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