From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 751A6C433F5 for ; Wed, 15 Dec 2021 09:25:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236355AbhLOJZQ (ORCPT ); Wed, 15 Dec 2021 04:25:16 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:36194 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233708AbhLOJZP (ORCPT ); Wed, 15 Dec 2021 04:25:15 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3A1F561853 for ; Wed, 15 Dec 2021 09:25:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95117C34600; Wed, 15 Dec 2021 09:25:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1639560314; bh=Boi5KTv+fWa939z6smBHV7KAPcNZQ8kMnVrmfnBWFlI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=uddsRJD6hj0c8/VgEn8k8fIcbDPzGfvheB9m3WA0i2jhpKKEzGIJblPpx82HXLv/6 jMAS6KVanLLcrADyzBJHfRR5yCnrnziSnIoHnkTZBZs7jLapCXuUYZK91KL0dHDuXP 2kSrEhpQn7bRYOTHGIUqdEWcP4iPXeirfWTtJ7FkmHx1xJ5Hz/1i1EfVAdNCHSCf2Z vAB/UnIaIbNk1EHWa9n1ZlqoNfqbIIlLKiZVCRuvMYhG8/WLLdmkmLTZLFShQgV0D+ tSs2X6KkvLU/kn7MbC1I8idmhFpQx93U2PVs2u/J0sbLRBw2dIPVOuE6jHszfY//8b mxHMKFV2a+BBg== Date: Wed, 15 Dec 2021 10:25:09 +0100 From: Mauro Carvalho Chehab To: Daniel Scally Cc: linux-media@vger.kernel.org, libcamera-devel@lists.libcamera.org, sakari.ailus@linux.intel.com, laurent.pinchart@ideasonboard.com, hanlinchen@chromium.org, tfiga@chromium.org, hdegoede@redhat.com, kieran.bingham@ideasonboard.com, hpa@redhat.com Subject: Re: [PATCH 0/5] Introduce ancillary links Message-ID: <20211215102509.2969578d@coco.lan> In-Reply-To: <20211213232849.40071-1-djrscally@gmail.com> References: <20211213232849.40071-1-djrscally@gmail.com> X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.30; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Em Mon, 13 Dec 2021 23:28:44 +0000 Daniel Scally escreveu: > Hello all > > At present there's no means in the kernel of describing the supporting > relationship between subdevices that work together to form an effective single > unit - the type example in this case being a camera sensor and its > corresponding vcm. To attempt to solve that, this series adds a new type of > media link called MEDIA_LNK_FL_ANCILLARY_LINK, which connects two instances of > struct media_entity. > > The mechanism of connection I have modelled as a notifier and async subdev, > which seemed the best route since sensor drivers already typically will call > v4l2_async_register_subdev_sensor() on probe, and that function already looks > for a reference to a firmware node with the reference named "lens-focus". To > avoid boilerplate in the sensor drivers, I added some new functions in > v4l2-async that are called in v4l2_async_match_notify() to create the ancillary > links - checking the entity.function of both notifier and subdev to make sure > that's appropriate. I haven't gone further than that yet, but I suspect we could > cut down on code elsewhere by, for example, also creating pad-to-pad links in > the same place. > > Thoughts and comments very welcome The idea of ancillary link sounds interesting. I did a quick look at the series. Laurent already did some good points during his review. Besides that, one thing it is missing, though, is an implementation on a driver. At least vimc should gain an implementation at this series, in order to allow media developers to test and see how the graph will be after the patch series. Regards, Mauro > > Dan > > Daniel Scally (5): > media: media.h: Add new media link type > media: entity: Add link_type() helper > media: entity: Skip non-data links in graph iteration > media: entity: Add support for ancillary links > media: v4l2-async: Create links during v4l2_async_match_notify() > > drivers/media/mc/mc-entity.c | 56 ++++++++++++++++++++++++++-- > drivers/media/v4l2-core/v4l2-async.c | 51 +++++++++++++++++++++++++ > include/media/media-entity.h | 29 ++++++++++++++ > include/uapi/linux/media.h | 1 + > 4 files changed, 134 insertions(+), 3 deletions(-) > Thanks, Mauro