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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 F34D4C433E7 for ; Tue, 13 Oct 2020 11:03:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AD13920E65 for ; Tue, 13 Oct 2020 11:03:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728441AbgJMLDp (ORCPT ); Tue, 13 Oct 2020 07:03:45 -0400 Received: from mail-out.m-online.net ([212.18.0.10]:32850 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727097AbgJMLDp (ORCPT ); Tue, 13 Oct 2020 07:03:45 -0400 Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4C9Xj93vk6z1sFh8; Tue, 13 Oct 2020 13:03:41 +0200 (CEST) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4C9Xj922Hwz1sM8t; Tue, 13 Oct 2020 13:03:41 +0200 (CEST) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id lbCJbeEq6Gsf; Tue, 13 Oct 2020 13:03:39 +0200 (CEST) X-Auth-Info: 7b7MojVlzhVUJfyHBIhRH0YBhJXoClv6jE7GG1MmNeA= Received: from [IPv6:::1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Tue, 13 Oct 2020 13:03:39 +0200 (CEST) Subject: Re: [PATCH v2 3/7] dt-bindings: display: mxsfb: Add a bus-width endpoint property To: Laurent Pinchart Cc: dri-devel@lists.freedesktop.org, Stefan Agner , devicetree@vger.kernel.org, =?UTF-8?Q?Guido_G=c3=bcnther?= , Rob Herring , Pengutronix Kernel Team , linux-arm-kernel@lists.infradead.org References: <20201007012438.27970-1-laurent.pinchart@ideasonboard.com> <20201007012438.27970-4-laurent.pinchart@ideasonboard.com> <7b8df7af-5ca8-708b-4975-2fdf4280116f@denx.de> <20201009235843.GR25040@pendragon.ideasonboard.com> <9c7615d6-0f69-5f67-0795-b86ecea2eea8@denx.de> <20201013020619.GG3942@pendragon.ideasonboard.com> From: Marek Vasut Message-ID: <13dfd626-f0a7-d05d-f90a-069c2389a16c@denx.de> Date: Tue, 13 Oct 2020 13:03:39 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20201013020619.GG3942@pendragon.ideasonboard.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 10/13/20 4:06 AM, Laurent Pinchart wrote: > Hi Marek, > > On Sat, Oct 10, 2020 at 10:47:05AM +0200, Marek Vasut wrote: >> On 10/10/20 1:58 AM, Laurent Pinchart wrote: >>> Hi Marek, >> >> Hi, >> >>> On Wed, Oct 07, 2020 at 10:40:26AM +0200, Marek Vasut wrote: >>>> On 10/7/20 3:24 AM, Laurent Pinchart wrote: >>>> >>>> [...] >>>> >>>>> + bus-width: >>>>> + enum: [16, 18, 24] >>>>> + description: | >>>>> + The output bus width. This value overrides the configuration >>>>> + derived from the connected device (encoder or panel). It should >>>>> + only be specified when PCB routing of the data signals require a >>>>> + different bus width on the LCDIF and the connected device. For >>>>> + instance, when a 18-bit RGB panel has its R[5:0], G[5:0] and >>>>> + B[5:0] signals connected to LCD_DATA[7:2], LCD_DATA[15:10] and >>>>> + LCD_DATA[23:18] instead of LCD_DATA[5:0], LCD_DATA[11:6] and >>>>> + LCD_DATA[17:12], bus-width should be set to 24. >>>> >>>> The iMX6 IPUv3 uses interface-pix-fmt which is a bit more flexible, but >>>> I'm not sure whether it's the right way to go about this, see: >>>> Documentation/devicetree/bindings/display/imx/fsl-imx-drm.txt >>> >>> I think specifying the bus with is better. It's a standard property, but >>> more than that, a given bus width can carry different formats. For >>> instance, a 24-bus could carry RGB666 data (with dithering for the >>> LSBs). >> >> I think that's exactly what the interface-pix-fmt was trying to solve >> for the IPUv3, there you could have e.g. both RGB666 and LVDS666 , which >> were different. > > My point is that the driver should support multiple formats that can be > carried over a given bus width, with the actual format to be used > queried from the sink (usually a panel) instead of being hardcoded in > DT. So, should the IPUv3 be fixed as well then ?