Re: [PATCH v2 61/66] dt-bindings: media: Add Allwinner A31 ISP bindings documentation

Laurent Pinchart
2022-02-11T20:52:50Z

Hi Rob,

On Fri, Feb 11, 2022 at 09:13:30AM -0600, Rob Herring wrote:
> On Mon, Feb 07, 2022 at 05:51:21PM +0200, Laurent Pinchart wrote:
> > On Sat, Feb 05, 2022 at 07:54:24PM +0100, Paul Kocialkowski wrote:
> > > This introduces YAML bindings documentation for the Allwinner A31 Image
> > > Signal Processor (ISP).
> > >
> > > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > > ---
> > > .../media/allwinner,sun6i-a31-isp.yaml | 117 ++++++++++++++++++
> > > 1 file changed, 117 insertions(+)
> > > create mode 100644 Documentation/devicetree/bindings/media/allwinner,sun6i-a31-isp.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-isp.yaml b/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-isp.yaml
> > > new file mode 100644
> > > index 000000000000..2d87022c43ce
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/allwinner,sun6i-a31-isp.yaml
> > > @@ -0,0 +1,117 @@
> > > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/media/allwinner,sun6i-a31-isp.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Allwinner A31 Image Signal Processor Driver (ISP) Device Tree Bindings
> > > +
> > > +maintainers:
> > > + - Paul Kocialkowski <paul.kocialkowski@bootlin.com>
> > > +
> > > +properties:
> > > + compatible:
> > > + enum:
> > > + - allwinner,sun6i-a31-isp
> > > + - allwinner,sun8i-v3s-isp
> > > +
> > > + reg:
> > > + maxItems: 1
> > > +
> > > + interrupts:
> > > + maxItems: 1
> > > +
> > > + clocks:
> > > + items:
> > > + - description: Bus Clock
> > > + - description: Module Clock
> > > + - description: DRAM Clock
> >
> > That's interesting, does the ISP have a dedicated DRAM ?
> >
> > > +
> > > + clock-names:
> > > + items:
> > > + - const: bus
> > > + - const: mod
> > > + - const: ram
> > > +
> > > + resets:
> > > + maxItems: 1
> > > +
> > > + ports:
> > > + $ref: /schemas/graph.yaml#/properties/ports
> > > +
> > > + properties:
> > > + port@0:
> > > + $ref: /schemas/graph.yaml#/$defs/port-base
> > > + description: CSI0 input port
> > > +
> > > + properties:
> > > + reg:
> > > + const: 0
> > > +
> > > + endpoint:
> > > + $ref: video-interfaces.yaml#
> > > + unevaluatedProperties: false
> >
> > If no other property than remote-endpoint are allowed, I'd write
> >
> > endpoint:
> > $ref: video-interfaces.yaml#
> > remote-endpoint: true
>
> You just mixed a node and a property...

Yes, I meant

endpoint:
$ref: video-interfaces.yaml#
properties:
remote-endpoint: true

and actually add

additionalProperties: false

> 'remote-endpoint' is always allowed, so need to put it here and every
> other user. So 'unevaluatedProperties' is correct. But it would be good
> to define what properties from video-interfaces.yaml are used here.

I've been looking at this recently. The usual pattern is to write

endpoint:
$ref: video-interfaces.yaml#
unevaluatedProperties: false
properties:
hsync-polarity: true
vsync-polarity: true

to express that the hsync-polarity and vsync-polarity properties are
used. However, this will still validate fine if, for instance,
data-lanes was specified in the device tree. Shouldn't we use
additionalProperties instead of unevaluatedProperties here ? If so,
specifying remote-endpoint: true seems needed.

--
Regards,

Laurent Pinchart