linux-kernel - [PATCH v3 0/2] regulator: qcom-rpmh: Add off-on-delay support

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Message-ID: <20260127190211.14312-1-bjsaikiran@gmail.com>
Date: Wed, 28 Jan 2026 00:32:09 +0530
From: Saikiran <bjsaikiran@...il.com>
To: broonie@...nel.org,
	lgirdwood@...il.com
Cc: andersson@...nel.org,
	konrad.dybcio@...nel.org,
	linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	robh@...nel.org,
	krzk+dt@...nel.org,
	devicetree@...r.kernel.org
Subject: [PATCH v3 0/2] regulator: qcom-rpmh: Add off-on-delay support

This series adds support for the standard `regulator-off-on-delay-us`
property to the Qualcomm RPMh regulator driver and updates the
corresponding Device Tree bindings.

Motivation:
On the Lenovo Yoga Slim 7x (Snapdragon X Elite), the camera regulators
(LDO1, LDO3, LDO7) have large bulk capacitors and rely on passive discharge.
When these regulators are disabled, the voltage decays very slowly. If
re-enabled too quickly, the sensor experiences a brownout and fails to
initialize.

Verification:
I verified that the core `drivers/regulator/of_regulator.c` does not
currently parse `regulator-off-on-delay-us` in `of_get_regulation_constraints()`.
Therefore, the driver must parse this property explicitly and populate
`rdesc->off_on_delay` so the regulator core can enforce the constraint.

Changes in v3:
- Added Patch 1/2: Update DT bindings to allow `regulator-off-on-delay-us`
  for `qcom,rpmh-regulator` (Requested by Mark Brown).
- Updated Patch 2/2: Refined commit message to explicitly mention the
  passive discharge and bulk capacitor mechanism on the Yoga Slim 7x
  (Requested by Mark Brown).

Changes in v2:
- Moved the motivation/context from the cover letter into the commit
  message of the driver patch.

Saikiran (2):
  dt-bindings: regulator: qcom,rpmh: Allow regulator-off-on-delay-us
  regulator: qcom-rpmh: Add support for regulator-off-on-delay-us