Re: [PATCH v3 2/3] media: dt-bindings: alvium: add document YAML binding

From: Conor Dooley
Date: Tue Jun 06 2023 - 14:08:03 EST


Hey Laurent, Tommaso,

On Tue, Jun 06, 2023 at 07:36:56PM +0300, Laurent Pinchart wrote:
> On Tue, Jun 06, 2023 at 05:54:03PM +0200, Tommaso Merciai wrote:

> > + alliedvision,lp2hs-delay-us:
> > + maxItems: 1
> > + description:
> > + Low power to high speed delay time in microseconds.
>
> You can drop "in microseconds", that's implied by the suffix.
>
> > + The purpose of this property is force a DPhy reset for the period
> > + described by the microseconds on the property, before it starts
> > + streaming. To be clear, with that value bigger than 0 the Alvium
> > + forces a dphy-reset on all lanes for that period. That means all
> > + lanes go up into low power state. This may help a csi2 rx ip to
> > + reset if that IP can't deal with a continous clock.
>
> I'd like to propose what I think is a clearer version:
>
> description: |
> Low power to high speed delay time.
>
> If the value is larger than 0, the camera forces a reset of all
> D-PHY lanes for the duration specified by this property. All lanes
> will transition to the low-power state and back to the high-speed
> state after the delay. Otherwise the lanes will transition to and
> remain in the high-speed state immediately after power on.
>
> This is meant to help CSI-2 receivers synchronizing their D-PHY
> RX.

Question about the property.
Why not make it have a minimum value of 1 and drop the special-case
behaviour for zero?

Cheers,
Conor.

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