Re: [PATCH v3 2/3] media: dt-bindings: alvium: add document YAML binding
From: Laurent Pinchart
Date: Wed Jun 07 2023 - 03:21:43 EST
On Wed, Jun 07, 2023 at 09:14:48AM +0200, Tommaso Merciai wrote:
> On Tue, Jun 06, 2023 at 07:07:42PM +0100, Conor Dooley wrote:
> > 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?
>
> Personally I prefer to stay with zero case.
> This reflect better the real camera register behaviour.
Speaking of which, could you document the maximum value in the bindings
?
> (also is optional)
--
Regards,
Laurent Pinchart