Re: [PATCH 2/2] arm: dts: dra76-evm: Disable rtc target module

[Tony Lindgren <tony@atomide.com>]

* keerthy <j-keerthy@ti.com> [190516 16:31]:
> 
> 
> On 5/16/2019 9:42 PM, Tony Lindgren wrote:
> > Hi,
> > 
> > * Keerthy <j-keerthy@ti.com> [190516 09:06]:
> > > rtc is fused out on dra76 and accessing target module
> > > register is causing a boot crash hence disable it.
> > 
> > So for a fix, can we have a separate dra7 something dtsi file
> > to disable these instead?
> > 
> > Or are there already multiple SoC revisions for the same EVM?
> 
> dra76 & dra71 have rtc fused out. So i did not introduce a new dtsi file
> to disable.

But then any new board with dra76 or dra71 will need to debug
the same issue again. Sure we can get away for now tweaking the
board file, but to me it sounds like it's going to be more
devices that will be affected too?

Is there some feature matrix available somewhere online?

> > Then in the long run, if there are the same EVMs with multiple
> > SoC options, the best thing to do is to would be to detect the
> > SoC type and update the property dynamically to set the features
> > not available on the booted SoC to status = "disabled". Seems
> > like that could be done in the ti-sysc driver probe unless needed
> > earlier.
> 
> For now rtc is disabled only in dra71/dra76. So best disable it in the
> evm.dts? Not sure if we need dynamic disabling as we know at DT level that
> it is to be disabled.

Well the thing is we should make introducing new board dts files
as easy as including the SoC dtsi file and with that it should
boot with no extra debugging.

How about add minimal dra76 and dra71 dtsi files in addition to
the board specific fix(es)? Then for v5.3, we can deal adding more
dra7 specifc evm files using these dtsi files or dynamically start
disabling modules.

Regards,

Tony