Re: [PATCH v5 06/10] dt-bindings: iio: accel: add interrupt-names

[Conor Dooley <conor@kernel.org>]

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On Thu, Dec 05, 2024 at 08:41:52PM +0100, Lothar Rubusch wrote:
> On Thu, Dec 5, 2024 at 6:54 PM Conor Dooley <conor@kernel.org> wrote:
> >
> > On Thu, Dec 05, 2024 at 05:13:39PM +0000, Lothar Rubusch wrote:
> > > Add interrupt-names INT1 and INT2 for the two interrupt lines of the
> > > sensor. Only one line will be connected for incoming events. The driver
> > > needs to be configured accordingly. If no interrupt line is set up, the
> > > sensor will still measure, but no events are possible.
> > >
> > > Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
> > > ---
> > >  .../devicetree/bindings/iio/accel/adi,adxl345.yaml         | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > >
> > > diff --git a/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml b/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
> > > index 280ed479ef5..67e2c029a6c 100644
> > > --- a/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
> > > +++ b/Documentation/devicetree/bindings/iio/accel/adi,adxl345.yaml
> > > @@ -37,6 +37,11 @@ properties:
> > >    interrupts:
> > >      maxItems: 1
> > >
> > > +  interrupt-names:
> > > +    description: Use either INT1 or INT2 for events, or ignore events.
> > > +    items:
> > > +      - enum: [INT1, INT2]
> >
> > The description for this ", or ignore events" does not make sense. Just
> > drop it, it's clear what happens if you don't provide interrupts.
> >
> > However, interrupts is a required property but interrupt-names is not.
> > Seems rather pointless not making interrupt-names a required property
> > (in the binding!) since if you only add interrupts and not
> > interrupt-names you can't even use the interrupt as you do not know
> > whether or not it is INT1 or INT2?
> 
> What I meant is, yes, the sensor needs an interrupt line.
> Interrupt-names is optional. The sensor always can measure. When
> interrupt-names is specified, though, the sensor will setup a FIFO and
> can use events, such as data ready, watermark, single tap, freefall,
> etc. Without the interrupt-names, the sensor goes into a "FIFO bypass
> mode" without its specific events.

What I'm talking about here is how it is ultimately pointless for
interrupts to be a required property if it can never be used without
interrupt-names as you cannot know which interrupt is in use. I think
both should be made mandatory or neither.

> Hence, I better drop the description entirely, since it rather seems
> to be confusing.

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