Re: [RFC v3] dt-binding: media: document ON Semi AR0521 sensor bindings

From: Sakari Ailus
Date: Tue Jul 27 2021 - 06:59:21 EST


Hi Krzysztof,

On Tue, Jul 27, 2021 at 12:36:20PM +0200, Krzysztof Hałasa wrote:
> Hi Laurent,
>
> Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> writes:
>
> >> + properties:
> >> + data-lanes:
> >> + anyOf:
> >> + - items:
> >> + - const: 1
> >> + - items:
> >> + - const: 1
> >> + - const: 2
> >> + - items:
> >> + - const: 1
> >> + - const: 2
> >> + - const: 3
> >> + - const: 4
> >
> > As the sensor also supports an HiSPi output, I would add the bus-type
> > property:
> >
> > data-lanes:
> > const: 4
>
> Is there any example of this? I'm not sure how should it it look like.
> Something like the following?
>
> properties:
> data-lanes:
> anyOf:
> - items:
> - const: 1
> - items:
> - const: 1
> - const: 2
> - items:
> - const: 1
> - const: 2
> - const: 3
> - const: 4
> bus-type:
> data-lanes:
> const: 4

I think Laurent meant:

bus-type:
const: 4

This way the bindings can be later amended with HiSPi support without
relying on defaults. Albeit the other busses in practice almost never end
up being used even if supported, apart from the standard BT.601, BT.656 and
CSI-2.

Either way is fine IMO.

>
> And... HiSPi would need additional code in the driver. And preferably
> some testing. I think I'd prefer to have DT and the driver staying in
> some sort of sync. Also, I'm uncertain about the syntax and the meaning
> of such, apparently redundant, construct. Nor about its relation to
> HiSPi. An example would be welcome.

No need to add support for the driver.

--
Sakari Ailus