From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail11.truemail.it (mail11.truemail.it [217.194.8.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2C7C539061C; Tue, 13 Oct 2026 12:50:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.194.8.81 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791895819; cv=none; b=PXbKR/EX91Bkq5lPYU1KNheUJXLum7N4GJzv3UXPvSi0uQS1WWdz1cL6Ag9UPotVFcHm9KI8gJbl6Nm92ZsTbIIOX9x/ual0bNBaabm/4/9oZ5y0CCHEp+gtZ3z1ttulAA8iXyFMNclczEDhmuMAWWRz/fgMPP1AWEKtVL8gTR0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791895819; c=relaxed/simple; bh=depoyDI+kx+4ryylKY71m6Q7qJvtM7ohRhEWVjSSpgY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kQ4FA1vi5ClYemBFZzCeQxETSdYrDtOi8uPsMr741zKVDNBddLFpDRR7honiI2/s4p+4Pg9+VTmxaY6rNUzxL4gEGgcJm785p/JRtoVzOQZXe6GTRngq629ppZfs+5glmiCk3e/vEXif5VAuU8at4Ar09Ut/XqYGmjuD/mjaLUU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=dolcini.it; spf=pass smtp.mailfrom=dolcini.it; dkim=pass (2048-bit key) header.d=dolcini.it header.i=@dolcini.it header.b=nmFIZ9/y; arc=none smtp.client-ip=217.194.8.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=dolcini.it Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=dolcini.it Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=dolcini.it header.i=@dolcini.it header.b="nmFIZ9/y" 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> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261013111158.GG56180@killaraus.ideasonboard.com> 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