Re: [PATCH/RFC v8 04/14] v4l2-async: change custom.match callback argument type
From: Jacek Anaszewski
Date: Mon Dec 01 2014 - 04:35:42 EST
On 11/29/2014 05:38 PM, Laurent Pinchart wrote:
Thank you for the patch.
On Friday 28 November 2014 10:17:56 Jacek Anaszewski wrote:
It is useful to have an access to the async sub-device
being matched, not only to the related struct device.
Change match callback argument from struct device
to struct v4l2_subdev. It will allow e.g. for matching
a sub-device by its "name" property.
In principle I agree. However, we will need to reimplement v4l2-async based on
the component (drivers/base/component.c) framework at some point. As the
component framework is based on struct device, will it still be possible to
match on subdev name in that case ? If not, we might need to try to find
another approach to the issue.
There were reservations raised  concerning the way of matching
by name, as the labels are not guaranteed to be globally unique across
Device Tree. I admit, this issue has to be solved in a different way.
Especially in view of prospective transition to using
I propose to add a new structure:
bool (*match)(struct v4l2_async_subdev *, void *);
and a function:
v4l2_async_register_subdev_with_match(struct v4l2_subdev *sd, struct
This way we could pass DT sub-node related to a sub-led in a priv
field of v4l2_asd_match upon registration.
This is similar approach as in case of drivers/base/component.c.
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