[PATCH v4 0/2] Enable DW9714V camera focus coil on SHIFT 6MQ

[David Heidelberg via B4 Relay <devnull+david.ixit.cz@kernel.org>]

Implements wiring for:
 - SGM2036 linear regulator used to turn on the focus coil [1]
 - Dongwoon 9714V focus coil used by IMX519 camera sensor [2]

[1] https://www.sg-micro.com/rect/assets/efa85993-263c-41aa-9274-b488f59f85d5/SGM2036.pdf
[2] https://datasheet4u.com/pdf/1247146/DW9714V.pdf

Open question for future work: modeling the I2C bus supply.

Like many similar chips, the DW9714 has a single VDD supply, but its I2C
lines go through a level shifter to a 1.8V rail, and there is currently no
place in DT to describe that rail so it gets enabled during I2C access to
the device. As a stopgap, this series models it as an always-on, see the
comment in the vreg_lvs1a_1p8 node).

Direction agreed with Rob Herring and Mark Brown on IRC:

 - Modeling the level shifter itself is overkill as long as it is just a
   supply; modeling the connector would come first if needed.
 - Since each side of the shifter has its own supply, the proper solution
   is a generic 'bus-supply' property valid in both the I2C controller and
   device nodes.
 - Defining it per-device-schema would ideally use an I2C equivalent of
   spi-peripheral-props.yaml, which does not exist yet. The pragmatic
   interim is to define bus-supply in i2c-controller.yaml for both places
   and add 'bus-supply: true' to schemas that need it now (dw9714),
   deferring the peripheral-props question until more shared device
   properties accumulate.

Once bus-supply exists, the regulator-always-on workaround in this DTS can
be dropped.

Signed-off-by: David Heidelberg <david@ixit.cz>
---
Changes in v4:
- Updated DT bindings commit description. (Sakari)
- Link to v3: https://patch.msgid.link/20260803-dw9714v-v3-0-8e10278dcd0d@ixit.cz

Changes in v3:
- Multiline compatible. (Konrad)
- Dropped output-low from avdd_cam pinctrl. (Konrad)
- Then dropped whole sleep pinctrl state, as it's same as default.
- Reworded the TODO. (Konrad)
- Dropped camss node. (claude)
- Moved before cdsp_pas (sort)
- Dropped unused regulator label.
- Switched the i2c bus shifter with the regulator VDD, as previously it
  was incorrectly wired and keep always-on on the i2c bus shifter.
- Link to v2: https://patch.msgid.link/20260730-dw9714v-v2-0-d5da19e6c60b@ixit.cz

Changes in v2:
- Address Sashiko findings.
- Link to v1: https://patch.msgid.link/20260729-dw9714v-v1-0-3c479b3cf8c0@ixit.cz

---
David Heidelberg (2):
      dt-bindings: media: i2c: dongwoon,dw9714: Document DW9714A and V variant
      arm64: dts: qcom: sdm845-shift-axolotl: Add actuator for main rear camera

 .../bindings/media/i2c/dongwoon,dw9714.yaml        | 14 +++++--
 arch/arm64/boot/dts/qcom/sdm845-shift-axolotl.dts  | 48 ++++++++++++++++++++++
 2 files changed, 59 insertions(+), 3 deletions(-)
---
base-commit: 95d6a9ccef99117115e41e9adb271243bd5e985b
change-id: 20260416-dw9714v-4566465ebe7d

Best regards,
--  
David Heidelberg <david@ixit.cz>