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 7F8EBEB8FC7 for ; Wed, 6 Sep 2023 13:15:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238095AbjIFNPE (ORCPT ); Wed, 6 Sep 2023 09:15:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45936 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237727AbjIFNPE (ORCPT ); Wed, 6 Sep 2023 09:15:04 -0400 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83748E7B for ; Wed, 6 Sep 2023 06:14:58 -0700 (PDT) Received: from pendragon.ideasonboard.com (ftip006315900.acc1.colindale.21cn-nte.bt.net [81.134.214.249]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id EECE5DA8; Wed, 6 Sep 2023 15:13:29 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1694006010; bh=T6KLPCFzBcPQrDgXo8rfqalUrUMmXF5Fb7lWmiX55kI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=muO56Yi2W26Jn0hAFdNvMV6jGrGCPKYp3FYM7xCFa8GBmfgJvcx4IwaLf4rK51NCU s7Vth4CqcaLbqJNu+UcSyZeadmv5ZpVO4v3gB3RuC5yJ1s/cFm/Hq4uZNZxmWdepSg mxD95cnrdHHKXKfECLb0m3JRMI6wU65UrnABDLKM= Date: Wed, 6 Sep 2023 16:15:10 +0300 From: Laurent Pinchart To: Sakari Ailus Cc: linux-media@vger.kernel.org, tomi.valkeinen@ideasonboard.com, bingbu.cao@intel.com, hongju.wang@intel.com, hverkuil@xs4all.nl, Andrey Konovalov , Jacopo Mondi , Dmitry Perchanov Subject: Re: [PATCH v3 09/10] media: Add media bus codes for MIPI CCS embedded data Message-ID: <20230906131510.GK17308@pendragon.ideasonboard.com> References: <20230808075538.3043934-1-sakari.ailus@linux.intel.com> <20230808075538.3043934-10-sakari.ailus@linux.intel.com> <20230905172535.GI7971@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org On Wed, Sep 06, 2023 at 01:03:18PM +0000, Sakari Ailus wrote: > On Tue, Sep 05, 2023 at 08:25:35PM +0300, Laurent Pinchart wrote: > > On Tue, Aug 08, 2023 at 10:55:37AM +0300, Sakari Ailus wrote: > > > Add new MIPI CCS embedded data media bus formats. > > > > > > Signed-off-by: Sakari Ailus > > > --- > > > .../media/v4l/subdev-formats.rst | 32 +++++++++++++++++++ > > > include/uapi/linux/media-bus-format.h | 10 +++++- > > > 2 files changed, 41 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst > > > index c615da08502d..5d5407738af9 100644 > > > --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst > > > +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst > > > @@ -8491,3 +8491,35 @@ and finally the bit number in subscript. "p" indicates a padding bit. > > > - p > > > - p > > > - p > > > + > > > +MIPI CCS Embedded Data Formats > > > +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > > > + > > > +`MIPI CCS `_ defines an > > > > s/an$/a/ > > Yes. I think I had "embedded" there in the past... > > > > +metadata format for sensor embedded data, which is used to store the register > > > +configuration used for capturing a given frame. The format is defined in the CCS > > > +specification. > > > > Strictly speaking, the MIPI CCS embedded data format specifies not just > > the data packing (insertion of padding bytes) and the data encoding (the > > data format byte and the tag codes), but also the register addresses and > > values that are reported in the embedded data. Do you envision the media > > bus formats defined here as being applicable to sensors that use the > > same packing and encoding as CCS, but different registers, or only to > > fully compliant CCS sensors ? > > There are sensors that aren't fully compatible with CCS (including those > compatible with SMIA and SMIA++) but I wouldn't expect the format to be > used by devices that are entirely incompatible with CCS. So if a sensor uses the same packing and encoding as CCS, but a different register set, you would require other media bus codes ? If so, how would you require those media bus codes to be documented ? The packing and encoding could be documented as being identical to CCS, but what about the data itself ? Would you require the datasheet to be public ? Or the entire register set being documented in the V4L2 spec ? -- Regards, Laurent Pinchart