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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 7A9FEC34022 for ; Mon, 17 Feb 2020 18:10:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 581D12070B for ; Mon, 17 Feb 2020 18:10:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="kVCs+/i5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726707AbgBQSKb (ORCPT ); Mon, 17 Feb 2020 13:10:31 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:58112 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729458AbgBQSKa (ORCPT ); Mon, 17 Feb 2020 13:10:30 -0500 Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id B1DDC1170; Mon, 17 Feb 2020 19:10:25 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1581963026; bh=LGYbPge+pK4TDEOF3sR06MljT1AaTQKK51QITDjD0Pk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=kVCs+/i5Nf8a+0zGj3upccoToJSu9p8u3ivFHBRadhN4iL2nQhJNoBXHV672rY3o1 jG2lTCpOryYQhy5snRE8bD9TA2r3ls+7jn+5nAP9uDAF0kiyE+rXTPY4I1VJnhQDID M++1Kyv+BqaaIwJGApOeTPOLhEUfTboaCsQ7FwB4= Date: Mon, 17 Feb 2020 20:10:06 +0200 From: Laurent Pinchart To: Maxime Ripard Cc: Chen-Yu Tsai , dri-devel@lists.freedesktop.org, Maarten Lankhorst , Sean Paul , Daniel Vetter , David Airlie , devicetree@vger.kernel.org, Mark Rutland , Rob Herring , Frank Rowand , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/2] dt-bindings: display: sun4i-tcon: Add LVDS Dual Link property Message-ID: <20200217181006.GE4830@pendragon.ideasonboard.com> References: <20200214123244.109300-1-maxime@cerno.tech> <20200214131025.GI4831@pendragon.ideasonboard.com> <20200214154405.f5zuicm6uhhiczfs@gilmour.lan> <20200214154953.GJ4831@pendragon.ideasonboard.com> <20200217174253.mj53us4bb7h2lyca@gilmour.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200217174253.mj53us4bb7h2lyca@gilmour.lan> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Maxime, On Mon, Feb 17, 2020 at 06:42:53PM +0100, Maxime Ripard wrote: > On Fri, Feb 14, 2020 at 05:49:53PM +0200, Laurent Pinchart wrote: > > On Fri, Feb 14, 2020 at 04:44:05PM +0100, Maxime Ripard wrote: > > > On Fri, Feb 14, 2020 at 03:10:25PM +0200, Laurent Pinchart wrote: > > > > On Fri, Feb 14, 2020 at 01:32:43PM +0100, Maxime Ripard wrote: > > > > > SoCs that have multiple TCONs can use the two set of pins on the first TCON > > > > > to drive a dual-link display. Add a property to enable the dual link. > > > > > > > > > > Signed-off-by: Maxime Ripard > > > > > --- > > > > > .../bindings/display/allwinner,sun4i-a10-tcon.yaml | 7 +++++++ > > > > > 1 file changed, 7 insertions(+) > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-tcon.yaml b/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-tcon.yaml > > > > > index 86ad617d2327..aa6dd8409dbc 100644 > > > > > --- a/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-tcon.yaml > > > > > +++ b/Documentation/devicetree/bindings/display/allwinner,sun4i-a10-tcon.yaml > > > > > @@ -105,6 +105,13 @@ properties: > > > > > - const: edp > > > > > - const: lvds > > > > > > > > > > + allwinner,lvds-dual-link: > > > > > + type: boolean > > > > > + description: | > > > > > + On a SoC with two TCON with LVDS support, the first TCON can > > > > > + operate over both pins sets to output in a dual-link setup. This > > > > > + will be triggered by setting this property. > > > > > > > > Could you maybe provide an example of how this property is supposed to > > > > be used ? I'm especially wondering what ports are used in that case and > > > > how they're connected. > > > > > > It's pretty trivial to support, it's only a property to set on the > > > encoder node itself. > > > > > > I'm not really sure what you meant by your question with the ports > > > though :/ > > > > I assume that, in the single-link case, you have two TCON instances that > > operate independently, each of them with one port that models an LVDS > > connection to a panel. > > Indeed, > > > In the dual-link mode, how does that look like ? Does the TCON > > instance that operate in dual-link mode have two ports in DT ? There > > are two physical ports, so I think it makes sense to always have two > > ports in DT. That's what we're doing for the LVDS encoders on R-Car > > Gen3, in order to specify in DT which LVDS input of the dual-link > > panel is connected to which LVDS output of the SoC. That allows > > configuring the LVDS encoder to send the even and odd pixels on the > > right port. > > As far as I can tell, you can't control that in our TCON. It just on > more lanes, that's it. Also, we currently have multiple ports, to map > another feature of the TCON, which is that it can drive directly a > panel, or will send its output to the HDMI / TV encoders. Adding > another port in that will break the current binding we have. This will create one issue though, in that the dual-link sinks are supposed to have two input ports, in order to expose the odd and even pixels ordering. If you have a single ouput port in your TCON, how will you interface with such sinks ? -- Regards, Laurent Pinchart