On Tue, Jun 06, 2023 at 07:07:42PM +0100, Conor Dooley wrote: > 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? The property is optional, so it can indeed be omitted if no delay is desired. I have no strong preference on whether or not to allow 0 as a valid value. -- Regards, Laurent Pinchart
