Re: [PATCH v4 1/3] [media] of: move graph helpers from drivers/media/v4l2-core to drivers/of

From: Laurent Pinchart
Date: Fri Mar 21 2014 - 10:28:41 EST

Hi Tomi,

On Friday 21 March 2014 16:22:52 Tomi Valkeinen wrote:
> On 21/03/14 16:13, Laurent Pinchart wrote:
> > On Friday 21 March 2014 15:37:17 Tomi Valkeinen wrote:
> >> On 21/03/14 00:32, Laurent Pinchart wrote:
> >>> The OF graph bindings documentation could just specify the ports node as
> >>> optional and mandate individual device bindings to specify it as
> >>> mandatory or forbidden (possibly with a default behaviour to avoid
> >>> making all device bindings too verbose).
> >>
> >> Isn't it so that if the device has one port, it can always do without
> >> 'ports', but if it has multiple ports, it always has to use 'ports' so
> >> that #address-cells and #size-cells can be defined?
> >
> > You can put the #address-cells and #size-cells property in the device node
> > directly without requiring a ports subnode.
> Ah, right. So 'ports' is only needed when the device node has other children
> nodes than the ports and those nodes need different #address-cells and
> #size-cells than the ports.

I would rephrase that as the ports node being required only in that case. It
can also be useful to cleanly group ports together when the device node has
other unrelated children, even though no technical requirement exist (yet ?)
in that case.

> In that case it sounds fine to leave it for the driver bindings to decide.


Laurent Pinchart

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