Hi Robin and Mark,

On 12/22/21 2:25 PM, Mark Brown wrote:

On Wed, Dec 22, 2021 at 01:19:23PM +0000, Robin Murphy wrote:

quoted

On 2021-12-22 13:00, Mark Brown wrote:

quoted

quoted

Does the SoC actually support the supply being completely off in
operation?  A lot of devices want everything powered even if idle during
full operation since keeping voltage differentials smaller makes it a
lot easier to design to avoid leakage current type issues at the points
where the different power domains connect.

quoted

I don't know TBH - the available documentation doesn't seem to go into quite
that much detail.

In that case I would tend to assume that unless otherwise stated it's
safer to keep the supply enabled when everything else is enabled.  It's
the default thing and so is more likely to be what was designed for and
less likely to result in nasty surprises.

Based on my experience with the RK3568 EVB1 the vdd_gpu supply turns
after startup if it is unused and the SoC works fine. Let's take the
energy efficient route here :-)

Best regards,
Michael

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