[PATCH 3/4] soc: rockchip: power-domain: Add regulator support

[Robin Murphy]

On 2021-12-22 13:00, Mark Brown wrote:
> On Wed, Dec 22, 2021 at 12:54:06PM +0000, Robin Murphy wrote:
> 
>> Certainly RK3399 (and I guess RK3288 too) suffers from the same
>> priority-inversion issue of being unaware that VD_GPU needs power before
>> PD_GPU can be successfully turned on to probe the GPU to claim and enable
>> the regulator (via "mali-supply" for DVFS purposes) that needed to be on in
>> the first place. Currently all the boards are bodging around this with
>> "regulator-always-on" (e.g. commit 06b2818678d9).
> 
> 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.

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

Robin.