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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 60AB7C88E77 for ; Wed, 16 Sep 2026 09:22:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=BTV5XMyrmHp39LHImMD7jLIBjdgbYzzgBsLUqmjYR3M=; b=lEdznMW0rAT5ktM81Q7Raia/d5 TJdcYAxQgt4K9QCUU9MLZGu5KyNwl7lJnP/GbUW3aOw9uxFhnWY2IplZgxmECKpD1nVjbrdCme7im vuQv+yUkagWUuxQhczOgmCzMCyIzl9zRtgYax2WfjetzzvnMV3dmyAdXNhR6uF6V2g7kybcTeEfGw K8YQ++FfUlws7x1BhPebuAh+oXlHCwmFXP1uecLAk6Lv3E1g0zP7fQemQD8MUbaaun7/3V20/aEQI StcwT5VB7LsHNWR9zGz/8ECb8kfIXdEu5mqZJx0aKjlM+MWpgqNZkagM18XLSdjXRYyFGXRp2da/P 4sYItm2g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6lqs-00000008pBq-2gkV; Wed, 16 Sep 2026 09:22:50 +0000 Received: from mail11.truemail.it ([2001:4b7e:0:8::81]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1x6lqo-00000008pAK-3GOJ for linux-arm-kernel@lists.infradead.org; Wed, 16 Sep 2026 09:22:50 +0000 Received: from francesco-nb (xcpe-178-82-167-143.dyn.res.sunrise.net [178.82.167.143]) by mail11.truemail.it (Postfix) with ESMTPA id 1CB4A22819; Wed, 16 Sep 2026 11:22:44 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dolcini.it; s=default; t=1789550564; bh=BTV5XMyrmHp39LHImMD7jLIBjdgbYzzgBsLUqmjYR3M=; h=From:To:Subject; b=T0JrFGj1/D4bssAaOGqKlJb+MlfTwpU+rmpdeUZaoGgTMQlHtWmIBgKSv6CPgR5pu CJOcJwIxs9Br5Grbb0Jgo4NsmF8jhNEmC+f3g3WM0fCsiPfH+ObpmpO8wCM4uT1qew V1rIi407+uL42ECJgC6e5fSOOvfWK4tWxnJJiYriUEeSeQzyrD87kt82LOEx7744rw JM+KJGHb+fy+2MoqMyzrWct/oZ5HhIfbMh8LNsQS3crESWCXOrgJ1R9ck25n6cXvzg 8VoH2BINXGyYMm0ZbsyNxb306RT3moHfBVGG+6IR+YXarl6NmMqkuF/5DKVMnyqT92 0W8BP2CYLyb/w== Date: Wed, 16 Sep 2026 11:22:42 +0200 From: Francesco Dolcini To: Luca Ceresoli Cc: Francesco Dolcini , Marek Vasut , Stefan Agner , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Francesco Dolcini , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v4 3/4] ARM: dts: imx6ull-colibri: Set LCDIF bus-width Message-ID: <20260916092242.GB277833@francesco-nb> References: <20260813092836.38367-1-francesco@dolcini.it> <20260813092836.38367-4-francesco@dolcini.it> <178954813309.214898.9623998050171113140.b4-review@b4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <178954813309.214898.9623998050171113140.b4-review@b4> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260916_022248_771932_B08FD9E7 X-CRM114-Status: GOOD ( 18.72 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Luca, thanks for the review. On Wed, Sep 16, 2026 at 10:42:13AM +0200, Luca Ceresoli wrote: > > The lcd DPI interface on colibri imx6ull uses a 18-bit width bus, set > > the bus-width property accordingly. > > > > Signed-off-by: Francesco Dolcini > > > > diff --git a/arch/arm/boot/dts/nxp/imx/imx6ull-colibri.dtsi b/arch/arm/boot/dts/nxp/imx/imx6ull-colibri.dtsi > > index ec3c1e7301f4..1eb1cf2d7395 100644 > > --- a/arch/arm/boot/dts/nxp/imx/imx6ull-colibri.dtsi > > +++ b/arch/arm/boot/dts/nxp/imx/imx6ull-colibri.dtsi > > @@ -229,6 +229,7 @@ &lcdif { > > > > port { > > lcdif_out: endpoint { > > + bus-width = <18>; > > I don't know the hardware in detail, but the datasheet [0] mentions 16, 18 > and 24 bits, and says "Up to 24-bit color (18-bit recommended)". More > details in ection 5.6.1. > > This patch would force 18 bits, but "recommended" suggests 24 bits makes > sense in some cases, no? > > Can you elaborate on this? The colibri family standard defines only 18-bit for the parallel RGB interface on the edge connector, the additional 6-bit are mapped on different pins that are not on fixed position, depend on the actual SoM and can also be not present at all. The standard/generic colibri family carrier boards can only rely on the 18-bits being available therefore. 24-bit is possible and makes sense only on a specific combo carrier+module, and not as a generic SoM feature. Assuming you would have such combo you should just override the property on the carrier board dts file deviating from the standard colibri family. let me know if you want such detailed explanation in the commit message Francesco