Re: [PATCH v2 2/3] ARM: dts: socfpga: fpga bridges bindings docs

Steffen Trumtrar
2014-10-27T15:32:29Z

On Mon, Oct 27, 2014 at 05:05:29PM +0200, Pantelis Antoniou wrote:
> Hi Mark,
>
> > On Oct 27, 2014, at 17:01 , Mark Brown <broonie@kernel.org> wrote:
> >
> > On Mon, Oct 27, 2014 at 01:48:02PM +0200, Pantelis Antoniou wrote:
> >>> On Oct 24, 2014, at 02:51 , atull@opensource.altera.com wrote:
> >
> >>> + - init-val : 0 if driver should disable bridge at startup
> >>> + 1 if driver should enable bridge at startup
> >>> + driver leaves bridge in current state if property not
> >>> + specified.
> >
> >> Isn’t init-val a boolean property? It’s not named very well.
> >
> > It's not boolean, it's tristate - turn on, turn off or don't touch.
> >
>
> I see. Even then ‘init-val’ is cryptic. I’d prefer two booleans,
> enable-at-startup; disable-at-startup.
>
> >> Along with the label, is kinda hard to defend as configuration in DT.
> >
> > Yeah... presumably this decision would fall out of the users?
>
> Well, it’s the user that should make the decision, but the driver should
> pick it up. This works but it’s not very nice.
>

Hm, convince me why this AXI bus is so special, that I even need an
"init-val" property? Other buses don't have that.
Why don't I add a property "init-val" to my SPI buses, so I can enable
it in the DT and still have it in reset, just because....

The bridges on the SoCFPGA are buses, from the HPS to the FPGA. If I have
written firmware to the FPGA and I have subnodes on that bus, I have to
get it out of reset and probe everything. Normal procedure, no ?!

Regards,
Steffen

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