Hi Rob, On Wednesday, 25 April 2018 20:11:23 EEST Rob Herring wrote: > On Wed, Apr 25, 2018 at 04:17:25PM +0300, Laurent Pinchart wrote: > > On Wednesday, 25 April 2018 15:20:04 EEST Philippe CORNU wrote: > >> On 04/25/2018 11:01 AM, Laurent Pinchart wrote: > >>> On Wednesday, 25 April 2018 10:53:13 EEST Philippe Cornu wrote: > >>>> Add optional power supplies using the description found in > >>>> "SiI9022A/SiI9024A HDMI Transmitter Data Sheet (August 2016)". > >>>> > >>>> There is a single 1v2 supply voltage named vcc12 from which cvcc12 > >>>> (digital core) and avcc12 (TMDS analog) are derived because according > >>>> to this data sheet: > >>>> "cvcc12 and avcc12 can be derived from the same power source" > >>> > >>> Shouldn't the power supplies be mandatory, as explained by Mark in > >>> https://lists.freedesktop.org/archives/dri-devel/2018-April/172400.html > >>> ? > >> > >> Laurent, > >> Many thanks Laurent for your comment, I understood the merge of the two > >> 1v2 power supplies but missed the "mandatory" part... maybe because this > >> patch (with optional power supplies) already got the reviewed-by from > >> Rob, I thought the discussion thread you pointed out was applicable > >> "only" to totally new driver documentation. > >> > >> So, on my side, as a "new user" of sii902x IC, no problem to put these > >> power supplies as mandatory instead of optional properties but I would > >> like to be sure this is applicable to both old and new bindings doc : ) > > > > We obviously need to retain backward compatibility, so on the driver side > > you need to treat those power supplies as optional. From a DT bindings > > point of view, however, I think they should be mandatory for new DT. > > We don't really have a way to describe these 3 conditions (required for > all, optional for all, and required for new). So generally we make > additions optional. The exception sometimes is if we update all the dts > files. Can't we just make it mandatory in the bindings, as long as we treat it as optional in drivers ? > >> Rob, > >> could you please confirm these power supply properties should be > >> "mandatory"? if yes, should we then modify other optional properties like > >> the reset-gpios too in the future? > > > > The GPIOs properties are different in my opinion, as there's no > > requirement to connect for instance the reset pin to a GPIO controllable > > by the SoC. The pin could be hardwired to VCC, or connected to a system > > reset that is automatically managed without SoC intervention. The power > > supplies, however, are mandatory, in the sense that the chip will not work > > if you leave the power supplies unconnected. > > DT only needs to describe what matters to s/w. If a regulator is > fixed and you don't need to know its voltage (or other read-only > parameters), then there's not much point in putting it in DT. > > I'd probably base this more at a platform level and you either use > regulator binding or you don't. It's perfectly valid that you want to do > things like regulator setup, pin ctrl and muxing setup, etc. all in > firmware and the OS doesn't touch any of that. > > That's all a big can of worms which we shouldn't solve on this 2 line > change. I think this change is fine as-is, so: > > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
