Re: [PATCH RFC v3 1/6] dt-bindings: iio: add OSF GREEN sensor aggregation device

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 29 May 2026 17:31:42 +0100
Conor Dooley <conor@kernel.org> wrote:

> On Fri, May 29, 2026 at 09:10:00PM +0900, Jinseob Kim wrote:
> > Describe OSF GREEN as the first board target.
> > 
> > Add vendor prefix and MAINTAINERS binding entry.
> > 
> > Signed-off-by: Jinseob Kim <kimjinseob88@gmail.com>
> > ---
> >  .../iio/imu/opensensorfusion,osf-green.yaml   | 43 +++++++++++++++++++
> >  .../devicetree/bindings/vendor-prefixes.yaml  |  2 +
> >  MAINTAINERS                                   |  5 +++
> >  3 files changed, 50 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/imu/opensensorfusion,osf-green.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/imu/opensensorfusion,osf-green.yaml b/Documentation/devicetree/bindings/iio/imu/opensensorfusion,osf-green.yaml
> > new file mode 100644
> > index 000000000..626b41fb0
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/imu/opensensorfusion,osf-green.yaml  
> 
> This is still not an IMU.

Might include one but agreed, it is more.  So probably move it up a a directory
to bindings/iio as it's more of a sensorhub.

> pw-bot: changes-requested
> 
> > @@ -0,0 +1,43 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/imu/opensensorfusion,osf-green.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: OSF GREEN sensor aggregation board
> > +
> > +maintainers:
> > +  - Jinseob Kim <kimjinseob88@gmail.com>
> > +
> > +description: |
> > +  OSF GREEN is an STM32F405-based sensor aggregation board from the Open
> > +  Sensor Fusion open hardware project. It sends OSF0 capability, status, and
> > +  sample frames to a host over a UART link.
> > +
> > +  Open Sensor Fusion is not a generic industry standard. Public project and
> > +  hardware documentation is available at:
> > +
> > +    https://github.com/opensensorfusion
> > +    https://github.com/opensensorfusion/opensensorfusion-hardware
> > +
> > +allOf:
> > +  - $ref: /schemas/serial/serial-peripheral-props.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: opensensorfusion,osf-green  
> 
> I'm still not convinced by the compatible here, or at least I am not
> convinced by it without clear answers to my questions on v1 about
> discoverability and compatibility between protocol versions. If the
> software on the "osf-green" is updatable (it is, right?) the compatible
> doesn't actually represent the hardware, it represents the programming
> model of what's exposed on the serial port to the host. That means the
> compatible you use has to identify the exact protocol version
> implemented, or provide enough information that the version can be
> figured out by software.
> 
> Given you talk about OSF0 communicating capability etc, it seems to me
> like OSF0 is a discoverable bus? In that case, compatibles for boards
> doesn't really matter, all software should need to know is that there is
> an OSF0 "bus" and query it for what sensors are there.

Agreed - should be very generic and rely on protocol discovery. Only
need to break that if some some silly reason the way protocol version is
discovered changes.

> 
> The questions I asked on v1 were:
> - What does "v0" mean here? Is the data format not complete yet?
> - Are versions of the protocol likely to be backwards compatible?
> - Will the device identify what version of the protocol it implements?
> 
> Remember, there's no rush here, and you're better off slowing down and
> taking your time responding to reviews before sending new versions, so
> that the same conversations don't take place multiple times.
> 
> Cheers,
> Conor.
>