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

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 [off-list ref] wrote:

quoted

Rob, Kunimori-san,

On Mon, Aug 26, 2024 at 10:40:09AM -0500, Rob Herring wrote:

quoted

On Mon, Aug 26, 2024 at 02:43:28AM +0000, Kuninori Morimoto wrote:

quoted

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(). 

quoted

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