[PATCH v3 2/9] of: property: add of_graph_get_next_port_endpoint()

[Sakari Ailus]

Hi Rob,

On Tue, Aug 27, 2024 at 09:05:02AM -0500, Rob Herring wrote:
> On Tue, Aug 27, 2024 at 5:47 AM Sakari Ailus <sakari.ailus at iki.fi> wrote:
> >
> > Rob, Kunimori-san,
> >
> > On Mon, Aug 26, 2024 at 10:40:09AM -0500, Rob Herring wrote:
> > > On Mon, Aug 26, 2024 at 02:43:28AM +0000, Kuninori Morimoto wrote:
> > > > We already have of_graph_get_next_endpoint(), but it is not
> > > > intuitive to use in some case.
> > >
> > > Can of_graph_get_next_endpoint() users be replaced with your new
> > > helpers? I'd really like to get rid of the 3 remaining users.
> >
> > The fwnode graph API has fwnode_graph_get_endpoint_by_id() which can also
> > be used to obtain endpoints within a port. It does the same than
> > of_graph_get_endpoint_by_regs() with the addition that it also has a
> > flags field to allow e.g. returning endpoints with regs higher than
> > requested (FWNODE_GRAPH_ENDPOINT_NEXT).
> 
> Looks to me like FWNODE_GRAPH_ENDPOINT_NEXT is always used with
> endpoint #0. That's equivalent to passing -1 for the endpoint number
> with the OF API.

If the caller needs a single endpoint only, then the two are the same, yes.
The NEXT flag can still be used for obtaining further endpoints, unlike
setting endpoint to -1 in of_graph_get_endpoint_by_regs(). 

> 
> > Most users dealing with endpoints on fwnode property API use this, could
> > something like this be done on OF as well? Probably a similar flag would be
> > needed though.
> 
> I had fixed almost all the OF cases at one point. Unfortunately, there
> were a few corner cases that I didn't address to eliminate the API. So
> now it has proliferated with the fwnode API.

Much of the usage of fwnode_graph_get_next_endpoint() is conversion from
the OF API but there are some newer drivers, too. I admit I've sometimes
missed this in review. At the same time I can say most users in the media
tree do employ fwnode_graph_get_endpoint_by_id() already.

The good thing is that almost all current users are camera sensors and
converting them is fairly trivial. I can post patches but it'll take a
while...

-- 
Kind regards,

Sakari Ailus