Hi Philippe, On Monday, 14 May 2018 12:22:16 EEST Philippe CORNU wrote: > On 04/26/2018 12:05 AM, Laurent Pinchart wrote: > > 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 ? > > How to progress on this patch? Do you have any suggestions? By seeing what Rob thinks about my proposal above ? :-) > >>>> 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
