[PATCH v3 0/2] iio: pressure: add Sensirion SDP31 driver

[Muhammad Abu Bakar]

This series adds support for the Sensirion SDP31 differential pressure
sensor, an I2C device that also reports temperature.

The SDP31 uses a completely different I2C command protocol from the
already supported SDP500 (command-triggered measurements with a per-word
CRC-8), so extending the sdp500 driver does not make sense. No compatible
parts from other vendors were found.

Patch 1 adds the device tree binding.
Patch 2 adds the IIO driver, which exposes differential pressure and
temperature channels and validates each measurement using the sensor's
CRC-8 checksum.

The driver was developed and tested on an SDP31 wired to the I2C bus of
a Raspberry Pi 4.

Changes since v2:
- Remove leftover development annotation comments from the driver.
- Drop the SDP31_TEMP_SCALE define and use the value inline.
- In sdp31_send_cmd(), separate the declaration of ret from the call so
  the call sits next to its error check.
- Add blank lines before the trailing return statements.
- Wait for the sensor's power-up time (datasheet t_PU) after enabling the
  regulator, before the first I2C transaction.

Changes since v1:
- dt-bindings: make vdd-supply required, and enable the regulator in the
  driver using devm_regulator_get_enable().
- Move the MAINTAINERS entry into the dt-bindings patch; the driver patch
  only adds its own file.
- Populate the CRC-8 table with DO_ONCE() to avoid a race between
  concurrent probes.
- Use devm_mutex_init() and take the lock inside sdp31_measure() using
  guard(mutex).
- Build the command with __be16/cpu_to_be16() and parse the reply with
  get_unaligned_be16().
- Use a named initializer in the i2c_device_id table.

v1: https://lore.kernel.org/linux-iio/20260919223650.13396-1-m.abubakar365@xxxxxxxxx/
v2: https://lore.kernel.org/linux-iio/20260920164533.31988-1-m.abubakar365@xxxxxxxxx/

Muhammad Abu Bakar (2):
  dt-bindings: iio: pressure: add Sensirion SDP31
  iio: pressure: add Sensirion SDP31 driver

 .../iio/pressure/sensirion,sdp31.yaml         |  41 ++++
 MAINTAINERS                                   |   6 +
 drivers/iio/pressure/Kconfig                  |  11 +
 drivers/iio/pressure/Makefile                 |   1 +
 drivers/iio/pressure/sdp31.c                  | 213 ++++++++++++++++++
 5 files changed, 272 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/pressure/sensirion,sdp31.yaml
 create mode 100644 drivers/iio/pressure/sdp31.c

-- 
2.43.0