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 DC1DCC433F5 for ; Wed, 15 Dec 2021 09:52:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241319AbhLOJwn (ORCPT ); Wed, 15 Dec 2021 04:52:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233733AbhLOJwn (ORCPT ); Wed, 15 Dec 2021 04:52:43 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DD92BC061574 for ; Wed, 15 Dec 2021 01:52:42 -0800 (PST) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 0F2C6292; Wed, 15 Dec 2021 10:52:40 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1639561961; bh=78AHd+3m++S+gX2fZ38+9vvLLDBXS9tzJ+NOscEhWFA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=t3NKqhHkKnrOL1AB7jpXcP7lEu6kC/m3rdTkYDOMQ5A5Bylzsj9t6DEm249DzJU0j XBNNj0M9tVv8xKMYeGKiI4MlV3D2oGD07u5c6/Yz2MvYPEGVvxBcl6xBHYtf0QyKhI EKGNx8+TVVDM0PFYjIy0NqnCmDZJXkCZS7kiaG6A= Date: Wed, 15 Dec 2021 11:52:38 +0200 From: Laurent Pinchart To: Mauro Carvalho Chehab Cc: Daniel Scally , linux-media@vger.kernel.org, libcamera-devel@lists.libcamera.org, sakari.ailus@linux.intel.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: References: <20211213232849.40071-1-djrscally@gmail.com> <20211215102509.2969578d@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20211215102509.2969578d@coco.lan> Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hi Mauro, On Wed, Dec 15, 2021 at 10:25:09AM +0100, Mauro Carvalho Chehab wrote: > 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. The whole point of patch 4/4 is to create those links in the core without requiring manual involvement of the drivers :-) > > 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(-) -- Regards, Laurent Pinchart