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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 28B00C433DF for ; Tue, 13 Oct 2020 02:07:11 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5B8D32078A for ; Tue, 13 Oct 2020 02:07:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="FWzWrgms" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B8D32078A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ideasonboard.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 65EFC6E03E; Tue, 13 Oct 2020 02:07:09 +0000 (UTC) Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id 61F7A6E03E for ; Tue, 13 Oct 2020 02:07:07 +0000 (UTC) Received: from pendragon.ideasonboard.com (62-78-145-57.bb.dnainternet.fi [62.78.145.57]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 3BEEDA42; Tue, 13 Oct 2020 04:07:05 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1602554825; bh=faWxdeUdzwGgd/jdihkSsVgvmpiWFPdtpRaopaRFFgU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FWzWrgms5AnQ5j0dxgRvZj1ljA30FYKM26WFUb4UG3G0QrOafcvS05e2JR4MMoSMZ mLD650iS6w2fq+3BI293vsXLWZBMw/Jh2ChVyV2N7lmh+ISjiwIriQ1R+kcBC9RqFq hoc688eHC3if1k1U7nA8ANv7QAUZqsTRYG4A+RYU= Date: Tue, 13 Oct 2020 05:06:19 +0300 From: Laurent Pinchart To: Marek Vasut Subject: Re: [PATCH v2 3/7] dt-bindings: display: mxsfb: Add a bus-width endpoint property Message-ID: <20201013020619.GG3942@pendragon.ideasonboard.com> 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> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <9c7615d6-0f69-5f67-0795-b86ecea2eea8@denx.de> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: devicetree@vger.kernel.org, Guido =?utf-8?Q?G=C3=BCnther?= , Rob Herring , dri-devel@lists.freedesktop.org, Pengutronix Kernel Team , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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. -- Regards, Laurent Pinchart _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel