[PATCH] arm64: dts: imx8mq: disable DDRC node by default

[Lucas Stach]

Am Sonntag, dem 12.12.2021 um 16:29 -0300 schrieb Fabio Estevam:
> Hi Lucas,
> 
> On Sun, Dec 12, 2021 at 4:16 PM Lucas Stach <dev at lynxeye.de> wrote:
> > 
> > Without a OPP table or a downstream TF-A running on the system the DDRC will
> > fail to probe, as it has no means to scale the DRAM frequency in that case.
> > This however will block the bus scaling driver to come up and this in turn
> > prevents other devices that hook into the interconnect from probing.
> > 
> > If the DDRC is disabled, the interconnect driver will simply ignore it. As
> > most systems don't want to scale the DRAM frequency, disable the node by
> > default and only enable it on the systems that actually uses this
> > capability and provides a valid OPP table in the DT.
> > 
> > Signed-off-by: Lucas Stach <dev at lynxeye.de>
> 
> Reviewed-by: Fabio Estevam <festevam at gmail.com>
> 
> Should we do the same on imx8mm too?

Not sure, with the i.MX8MM there are a lot more systems that are
providing a valid OPP table. Also I don't see the interconnect being
hooked up to devices in the i.MX8MM DT, so a non-function interconnect
driver, will at least not block other devices as is the case with the
i.MX8MQ.

However, there still is the issue that all those systems those depend
on a downstream TF-A running on the system, as upstream TF-A has no
support for scaling the DDR frequency.

Regards,
Lucas