Re: [PATCH 00/04] pinctrl: sh-pfc: r8a7794: DU support

Laurent Pinchart
2015-11-20T14:53:05Z

Hi Magnus,

On Friday 20 November 2015 16:16:15 Magnus Damm wrote:
> On Fri, Nov 20, 2015 at 11:46 AM, Laurent Pinchart wrote:
> > On Tuesday 17 November 2015 12:18:32 Magnus Damm wrote:
> >> pinctrl: sh-pfc: r8a7794: DU support
> >>
> >> [PATCH 01/04] pinctrl: sh-pfc: r8a7794: Add DU pin groups
> >> [PATCH 02/04] pinctrl: sh-pfc: r8a7794: Separate DU CDE and DISP
> >> [PATCH 03/04] pinctrl: sh-pfc: r8a7794: Add missing dot clock signals
> >> [PATCH 04/04] pinctrl: sh-pfc: r8a7794: Break out ODDF from sync
> >>
> >> These patches take the r8a7794 PFC DU support code from the BSP
> >> and reworks it to fit the r8a7794 ALT board. Tested with the ALT
> >> VGA port - by default PFC is not used however enabling PFC using
> >> an incremental (yet to be posted) patch works well.
> >>
> >> It is worth noting that patch 2-4 modifies the pin groups. This
> >> means that the upstream DT ABI for PFC DU will differ compared
> >> to the unreviewed BSP code.
> >>
> >> In general it is not considered good practice to change the pin
> >> groups and break compatibility since they are part of the DT ABI.
> >>
> >> For this particular case upstream never have had PFC DU support
> >> for r8a7794, so treating the BSP bindings as experimental and
> >> migrate away seems reasonable.
> >
> > If we start considering DT bindings that never went upstream as stable
> > we'll have a big problem. I mean even bigger than the upstream DT
> > bindings stability problem :-)
>
> I'm not saying that local DT hacks should be considered stable, more
> that it as usual makes sense to follow upstream first with proper DT
> review process early on.
>
> >> Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
> >
> > Wouldn't it make sense to merge the 4 patches together ?
>
> Yeah, I guess so. My feeling is also that it would be good to verify
> HDMI on ALT before commiting to DT bindings. Right now only one DU
> channel is tested.

I agree with that.

--
Regards,

Laurent Pinchart