Re: [RFC PATCH v1 0/4] iio: add Sensirion SLF3x liquid flow sensor support

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 24 May 2026 22:49:35 +0200
Wadim Mueller <wafgo01@gmail.com> wrote:

> From: Wadim Mueller <wadim.mueller@cmblu.de>
> 
> Hi all,
> 
> this RFC adds support for the Sensirion SLF3x family of liquid-flow
> sensors (SLF3S-0600F and SLF3S-4000B).  Before I send it as a normal
> patch I'd like to ask three things:
> 
> 1. Subsystem.  Liquid-flow sensors don't seem to have a home in
>    mainline yet.  iio/ feels like the natural place for me, but
>    please correct me if hwmon (or somewhere else) is prefered.

I'm fine with this type of sensor in IIO, but open to hear from others!

> 
> 2. Channel type.  IIO has no flow channel type so far.  The series
>    adds IIO_VOLUMEFLOW with _scale in litres per second per LSB,
>    so drivers reporting smaller units only need a fractional scale.
>    IIO_MASSFLOW (for gas-flow sensors) was left out on purpose --
>    happy to add it in the same series if that's more usefull.

Would be good to have a little more detail on difference etc to have
that discussion.  Superficially I'm assuming this is a compressible vs
non compressible thing?

> 
> 3. Subdirectory.  I put the driver in a new drivers/iio/flow/
>    since there is no flow subsytem in iio yet.  If colocating with
>    drivers/iio/pressure/ (next to sdp500) is preferred I'll respin.

This is easy to change later if we make a wrong decision. For now I think
iio/flow is fine.

Thanks

Jonathan


> 
> Patches:
> 
>   1/4  iio: types: add IIO_VOLUMEFLOW channel type
>   2/4  dt-bindings: iio: flow: add sensirion,slf3s binding
>   3/4  iio: flow: add Sensirion SLF3x driver
>   4/4  MAINTAINERS: add entry
> 
> Tested with a SLF3S-0600F on a TI AM64x platform.
> 
> Thanks,
> Wadim
> 
> Wadim Mueller (4):
>   iio: types: add IIO_VOLUMEFLOW channel type
>   dt-bindings: iio: flow: add Sensirion SLF3x liquid flow sensor
>   iio: flow: add Sensirion SLF3x liquid flow sensor driver
>   MAINTAINERS: add entry for Sensirion SLF3x flow sensor driver
> 
>  Documentation/ABI/testing/sysfs-bus-iio       |  17 ++
>  .../bindings/iio/flow/sensirion,slf3s.yaml    |  49 ++++
>  MAINTAINERS                                   |   7 +
>  drivers/iio/Kconfig                           |   1 +
>  drivers/iio/Makefile                          |   1 +
>  drivers/iio/flow/Kconfig                      |  22 ++
>  drivers/iio/flow/Makefile                     |   7 +
>  drivers/iio/flow/slf3x.c                      | 264 ++++++++++++++++++
>  drivers/iio/industrialio-core.c               |   1 +
>  include/uapi/linux/iio/types.h                |   1 +
>  tools/iio/iio_event_monitor.c                 |   2 +
>  11 files changed, 372 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/flow/sensirion,slf3s.yaml
>  create mode 100644 drivers/iio/flow/Kconfig
>  create mode 100644 drivers/iio/flow/Makefile
>  create mode 100644 drivers/iio/flow/slf3x.c
> 
> 
> base-commit: 3cd8b194bf3428dfa53120fee47e827a7c495815