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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=BAYES_00, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3201EC433E0 for ; Wed, 29 Jul 2020 07:35:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1AD182065E for ; Wed, 29 Jul 2020 07:35:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726710AbgG2Hfk (ORCPT ); Wed, 29 Jul 2020 03:35:40 -0400 Received: from smtp08.smtpout.orange.fr ([80.12.242.130]:46003 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726336AbgG2Hfk (ORCPT ); Wed, 29 Jul 2020 03:35:40 -0400 Received: from belgarion ([86.210.166.159]) by mwinf5d67 with ME id 8vbW2300K3SgWc603vbbFk; Wed, 29 Jul 2020 09:35:38 +0200 X-ME-Helo: belgarion X-ME-Auth: amFyem1pay5yb2JlcnRAb3JhbmdlLmZy X-ME-Date: Wed, 29 Jul 2020 09:35:38 +0200 X-ME-IP: 86.210.166.159 From: Robert Jarzmik To: Hans Verkuil , Jacopo Mondi Cc: Janusz Krzysztofik , mchehab@kernel.org, sakari.ailus@linux.intel.com, laurent.pinchart@ideasonboard.com, niklas.soderlund+renesas@ragnatech.se, kieran.bingham@ideasonboard.com, dave.stevenson@raspberrypi.com, hyun.kwon@xilinx.com, linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH v6 1/9] media: v4l2-subdev: Introduce [get|set]_mbus_config pad ops References: <20200714135812.55158-1-jacopo+renesas@jmondi.org> <20200714135812.55158-2-jacopo+renesas@jmondi.org> <750089f9-0e7f-3b2a-ec85-38452cb64fa1@xs4all.nl> <4043309.ejJDZkT8p0@z50> X-URL: http://belgarath.falguerolles.org/ Date: Wed, 29 Jul 2020 09:35:30 +0200 In-Reply-To: (Hans Verkuil's message of "Mon, 20 Jul 2020 10:48:36 +0200") Message-ID: <87zh7isri5.fsf@belgarion.home> User-Agent: Gnus/5.130008 (Ma Gnus v0.8) Emacs/26 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org Hans Verkuil writes: > The information on how a sensor (or similar device) is wired up is not something > that should be negotiated. Even if a combination is theoretically possible, it > may not have been tested by the board designer and in fact it might not work. > (Yes, that happens) > > It is just a bad design trying to negotiate this. I quite agree on that one (on the wiring defined by configuration). > In fact, the only values that can be set as far as I am concerned are lanes and > channels. I wouldn't mind if the other settings are purely read-only. The only > driver that actively sets this is the pxa_camera driver and I wish it didn't. > > But there are still two pxa boards that use this mechanism, so I guess we still > have to allow this. There are 4 : rj@belgarion:~/mio_linux/kernel/arch/arm/mach-pxa$ grep -rs pxa_set_camera * | grep -v devices.c ezx.c: pxa_set_camera_info(&a780_pxacamera_platform_data); ezx.c: pxa_set_camera_info(&a910_pxacamera_platform_data); mioa701.c: pxa_set_camera_info(&mioa701_pxacamera_platform_data); palmz72.c: pxa_set_camera_info(&palmz72_pxacamera_platform_data); pcm990-baseboard.c: pxa_set_camera_info(&pcm990_pxacamera_platform_data); I wouldn't mind that the bus parameters are made "static" by forcing them in the platform data field (struct pxacamera_platform_data), and not doing the bus compatibility matching. I thing Jacopo's work is going this way, as I read that his patch takes first the platform data flags, and only if none are defined goes to the matchup. That looks very sensible to me. Cheers. -- Robert