Message-Id: <20251022-add-rpmh-read-support-v2-0-5c7a8e4df601@oss.qualcomm.com>
Date: Wed, 22 Oct 2025 02:38:52 +0530
From: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
To: Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>
Cc: linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>,
        Maulik Shah <maulik.shah@....qualcomm.com>,
        David Collins <david.collins@....qualcomm.com>
Subject: [PATCH v2 0/4] Add support to read RPMH regulator settings

This patch series adds a new `rpmh_read()` API to allow reading RPMH
addresses. Also, using this new API, enhances the RPMH regulator driver
get_regulator* APIs like `get_regulator_sel()`, `get_mode()` and
`get_status()` to allow reading voltage/mode/enable setting from H/W.

This is needed because current design has a limitation - regulator
framework can only get the cached values from the last voltage set
operation. Because of this right after bootup a `get_voltage_sel()`
from regulator framework will return -ENOTRECOVERABLE error, causing
regulator framework to trigger an unnecessary `set_voltage_sel()` call
with the `min_uV` value specified in the regulator's device tree
settings, which can cause issues for consumers like the display and
UFS that require a consistent voltage setting from the bootloader
state until their drivers are probed.

With this change regulator framework will get the regulator voltage
and other settings, as configured during bootloader stage, avoiding
unnecessary voltage adjustments and maintaining consistent power
settings across the transition from bootloader to kernel.

Besides this feature this series also fixes:-
- An existing issue with the BOB5 pass code value. This is needed
  by `get_status()`.
- Code format/style related errors reported by checkpatch.pl.

Signed-off-by: Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>
---
Changes in v2:
- Fixed the BOB bypass mode handling (existing issue in current driver).
  This was needed for `get_status()` implementation.
- Implemented `get_status()` callback.
- Callbacks for `is_enabled()` & `get_mode()` will now be used as-is
  ie. v1 changes reverted.
- Bootstapped the read values for `mode` and `status` in probe, based on
  comments recieved from reviewer. 
- Callback for `get_voltage_sel()` has been modified to handle cases
  where read voltage is out-of-range defined in the regulator DT settings,
  this is needed to ensure backward compatibilty. Regulator probes may
  fail otherwise for some older targets.
- This patch is rebased & tested on:
   https://lore.kernel.org/all/176070318151.57631.15443673679580823321.b4-ty@kernel.org/
  to avoid any merge issues.
- Fixed code style issues reported by checkpatch.pl script. 
- Link to v1: https://lore.kernel.org/r/20250623-add-rpmh-read-support-v1-0-ae583d260195@oss.qualcomm.com

---
Kamal Wadhwa (3):
      regulator: rpmh-regulator: Fix PMIC5 BOB bypass mode handling
      regulator: qcom-rpmh: Add support to read regulator settings
      regulators: qcom-rpmh-regulator: Fix coding style issues

Maulik Shah (1):
      soc: qcom: rpmh: Add support to read back resource settings

 drivers/regulator/qcom-rpmh-regulator.c | 184 +++++++++++++++++++++++++++++++-
 drivers/soc/qcom/rpmh-rsc.c             |  13 ++-
 drivers/soc/qcom/rpmh.c                 |  47 +++++++-
 include/soc/qcom/rpmh.h                 |   5 +
 include/soc/qcom/tcs.h                  |   2 +
 5 files changed, 241 insertions(+), 10 deletions(-)
---
base-commit: fe45352cd106ae41b5ad3f0066c2e54dbb2dfd70
change-id: 20250623-add-rpmh-read-support-3288f83cc20a

Best regards,
-- 
Kamal Wadhwa <kamal.wadhwa@....qualcomm.com>

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