Re: [PATCH v3 1/2] dt-bindings: regulator: qcom,rpmh: Allow regulator-off-on-delay-us

[Kamal Wadhwa]

On Sun, Feb 08, 2026 at 06:37:24PM +0530, Saikiran B wrote:
> On Fri, Feb 6, 2026 at 9:50 PM Kamal Wadhwa
> <kamal.wadhwa@xxxxxxxxxxxxxxxx> wrote:
> >
> > On Tue, Feb 03, 2026 at 04:30:27PM +0000, Mark Brown wrote:
> > > On Tue, Feb 03, 2026 at 09:50:05PM +0530, Kamal Wadhwa wrote:
> > >
> > > > But I'm wondering if this is really a 'slow discharge' issue, because if the
> 
> Hi Kamal,
> 
> Thanks for checking the internal register defaults.
> 
> I can confirm it is definitely related to the power-cycling state. While I
> haven't probed the pads, I validated this with two software tests:
> 
> 1. The Always On Test: I modified the driver to keep the regulators
>    permanently enabled (never turning off). In this state, the camera works
>    100% of the time, even with rapid open/close cycles. This proves the
>    crash is triggered specifically by the power-down event.
> 
> 2. The Timing Threshold: Through iterative testing, I found that reopening
>    the camera fails consistently if the off-time is <2.0s, but succeeds if
>    the off-time is >2.3s. This 2.3s window matches the calculated RC time
>    constant for a passive discharge on these rails.
> 
> If the Strong Pull Down were effectively active, the rails should drain in
> milliseconds. The fact that it requires 2.3s suggests that on this unit,
> the PD is either effectively disabled or too weak for the bulk capacitance
> present.
> 
> As I mentioned to Mark, I have withdrawn this specific delay patch to
> investigate if I can manually enforce Active Discharge (via direct RPMh
> commands) to solve this at the source. But now, your note that these settings
> might be locked is concerning.

I discussed about your concerns, and it seems that we have some boot side DT config 
that can be configured to enable/disable the strong PD ( its not available
from HLOS though)

you can refer to Doc for same here:-
https://docs.qualcomm.com/doc/80-70023-4/topic/tools.html?product=895724676033554725&facet=Boot&version=1.7

forum to ask questions about it:-
https://mysupport.qualcomm.com/supportforums/s/

> 
> Regards,
> Saikiran