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 9A69BCC6B08 for ; Tue, 13 Oct 2026 12:50:40 +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=gIIe7Oi+djZ9XgtHUXw31H42TUuD0xP0hAFUDgxj2bU=; b=klZ0NXbxswMfHsEz71qD1C0he7 UeWzYFHMWZWPWgLYagmXXCAu+hmtZkMm06iwqClaeET1X8/Zv4ec9FRquUaErnY7AnXuTTYSpFzdp wNljf0rdM3YXG8IPQLLS4HXDgQQygoPKm0DYMlnGnpLCs33qYT2WwJWsnyYEvF5ALsKCZ8/CKykq4 lDiRjqEAF2r2Kd0e4S9Wjfzv84ktTYNzsoiQ5mzeknmKHYyaZu43e5t3KtLEyBvYSCAhDfzadSKW6 G3EEawgKZW8yNxeYgP/m+ZQ4baUIYHKCYnEBeMu88oxPTBBhjLS7cYnXYFHsjhCpe1MOa4jDzRn+8 MsyxXdPw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xGbxh-0000000Crx5-1UOx; Tue, 13 Oct 2026 12:50:33 +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 1xGbxS-0000000Crav-16ay for linux-arm-kernel@lists.infradead.org; Tue, 13 Oct 2026 12:50:29 +0000 Received: from francesco-nb (248.201.173.83.static.wline.lns.sme.cust.swisscom.ch [83.173.201.248]) by mail11.truemail.it (Postfix) with ESMTPA id 30FC31FA7B; Tue, 13 Oct 2026 14:50:14 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dolcini.it; s=default; t=1791895815; bh=gIIe7Oi+djZ9XgtHUXw31H42TUuD0xP0hAFUDgxj2bU=; h=From:To:Subject; b=nmFIZ9/ygIVjsJ+MFJOliYWK15FxmtiHwLb1yir2UWXDHQzZe/lNhR6cCWLXfERX+ U/CU5C9Rb2PzY7pmzWpQrE1ub+62YmLDTzrO2r8tfszo/jPxbVgrfmWphOgxTp5ZMa GhRh5Pq8he1TT12R4H40qzivyWsNTks5OKRZPiApYbXMNJGWQxg9Y56nX3Eo4kshJm Mfvg4ANNyC8BVdagjE3Epp20tpDj33S2saBFU8AZ7n9OQlCSUhTcsvy39iR2U5QWMG k+gyFjAMMA1+TXVvSJXU6wa6NwQ00y6uwcJPHNT7u78y2qAo+PdGoe9uc8DuDngorT NXedGwmBcUUnw== Date: Tue, 13 Oct 2026 14:50:12 +0200 From: Francesco Dolcini To: Laurent Pinchart Cc: Francesco Dolcini , Leonardo Costa , Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Luca Ceresoli , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Leonardo Costa Subject: Re: [PATCH 0/3] Add VGA support for Apalis iMX6 Message-ID: <20261013125012.GB73534@francesco-nb> References: <20261012-v1-apalis-imx6-enable-vga-v1-0-8905d8746504@toradex.com> <20261012164054.GA56180@killaraus.ideasonboard.com> <20261013090631.GA33628@francesco-nb> <20261013111158.GG56180@killaraus.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261013111158.GG56180@killaraus.ideasonboard.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261013_055024_237429_4D902FFE X-CRM114-Status: GOOD ( 22.92 ) 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 On Tue, Oct 13, 2026 at 01:11:58PM +0200, Laurent Pinchart wrote: > On Tue, Oct 13, 2026 at 11:06:31AM +0200, Francesco Dolcini wrote: > > On Mon, Oct 12, 2026 at 06:40:54PM +0200, Laurent Pinchart wrote: > > > On Mon, Oct 12, 2026 at 04:25:22AM -0300, Leonardo Costa wrote: > > > > This series adds a device tree overlay that enables the VGA output on Apalis > > > > iMX6, which is driven from a parallel RGB interface passing through a > > > > non-programmable video DAC. > > > > > > > > The video DAC is a simple resistor network gated by an active-low > > > > data-enable signal. For the bridge to work properly, this series also > > > > changes the following in the dt-bindings and simple-bridge driver: > > > > > > > > - dt-bindings: Add a new compatible for the bridge in the simple-bridge > > > > binding. This is necessary because the existing dumb-vga-dac compatible > > > > doesn't describe a data-enable signal polarity. > > > > > > > > - simple-bridge: Add the VGA bridge match-table entry and timings > > > > struct, setting the DRM_BUS_FLAG_DE_LOW flag for the bridge. > > > > > > Is there schematics available anywhere ? That would help reviewing the > > > series ? > > > > This circuit is on the SoM, and the SoM schematics are > > confidential and not generally available. > > > > I tried to extract as ascii art the relevant circuit, hope it helps > > Thank you, it makes things clearer. > > The circuit seems fairly generic. Wouldn't it be better to add an > optional property ot the dumb-vga-dac instead of a new compatible string > specific to Apalis ? We discussed this internally and we were not 100% sure, so we decided to go with this proposal that seemed easier and less controversial. With that wrote, I let Leonardo comment on the pro/cons of the two approaches. Francesco