Re: [PATCH 14/54] dt-bindings: hwmon: Add IIO HWMON binding

[Rob Herring <robh@kernel.org>]

On Thu, Jul 22, 2021 at 11:34:53AM +0200, Maxime Ripard wrote:
> Hi Jonathan,
> 
> On Thu, Jul 22, 2021 at 10:20:27AM +0100, Jonathan Cameron wrote:
> > On Wed, 21 Jul 2021 16:03:44 +0200
> > Maxime Ripard <maxime@cerno.tech> wrote:
> > 
> > > Even though we had the iio-hwmon driver for some time and a number of
> > > boards using it already, we never had a binding for it. Let's add it
> > > based on what the driver expects and the boards are providing.
> > > 
> > > Cc: Guenter Roeck <linux@roeck-us.net>
> > > Cc: Jean Delvare <jdelvare@suse.com>
> > > Cc: Jonathan Cameron <jic23@kernel.org>
> > > Cc: linux-hwmon@vger.kernel.org
> > > Signed-off-by: Maxime Ripard <maxime@cerno.tech>
> > > ---
> > >  .../devicetree/bindings/hwmon/iio-hwmon.yaml  | 37 +++++++++++++++++++
> > >  1 file changed, 37 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/hwmon/iio-hwmon.yaml
> > > 
> > > diff --git a/Documentation/devicetree/bindings/hwmon/iio-hwmon.yaml b/Documentation/devicetree/bindings/hwmon/iio-hwmon.yaml
> > > new file mode 100644
> > > index 000000000000..49dd40f663a6
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/hwmon/iio-hwmon.yaml
> > > @@ -0,0 +1,37 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: "http://devicetree.org/schemas/hwmon/iio-hwmon.yaml#"
> > > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > > +
> > > +title: ADC-attached Hardware Sensor Device Tree Bindings
> > > +
> > > +maintainers:
> > > +  - Jonathan Cameron <jic23@kernel.org>
> > 
> > I'd like to share the blame for this one.  Binding was originally added
> > by Guenter.
> > 
> > https://lore.kernel.org/linux-iio/1359668588-13678-4-git-send-email-linux@roeck-us.net/
> > https://lore.kernel.org/linux-iio/1359668588-13678-11-git-send-email-linux@roeck-us.net/
> > :)
> > 
> > As bindings go this one has always been controversial because
> > it's mapping between linux subsystems rather than really describing
> > hardware.  We've had various discussions over the years on how to do
> > this differently, but perhaps just documenting the current state is the
> > way to go.  That doesn't stop us moving to something better in the
> > future.
> 
> There's DT using it already, so I guess it's a bit too late to have that
> discussion indeed :)
> 
> > > +
> > > +description: >
> > > +  Bindings for hardware monitoring devices connected to ADC controllers
> > > +  supporting the Industrial I/O bindings.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: iio-hwmon
> > > +
> > > +  io-channels:
> > > +    minItems: 1
> > > +    maxItems: 1024
> > 
> > Why 1024?
> 
> Ought to be enough for anyone :)
> 
> We have to set a maximum and I couldn't find any actual maximum
> documented, if you prefer another value let me know

Just add a comment: '# Should be enough'