From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boris Brezillon Subject: Re: [PATCH v7 10/11] ARM: at91/dt: add LCD panel description to sama5d3xdm.dtsi Date: Mon, 6 Oct 2014 15:11:11 +0200 Message-ID: <20141006151111.446ed7d6@bbrezillon> References: <1412175188-28278-1-git-send-email-boris.brezillon@free-electrons.com> <1412175188-28278-11-git-send-email-boris.brezillon@free-electrons.com> <20141006110115.GH25202@ulmo> <20141006142538.76d2df29@bbrezillon> <20141006124014.GD26833@ulmo> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20141006124014.GD26833@ulmo> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Thierry Reding Cc: Mark Rutland , linux-pwm@vger.kernel.org, devicetree@vger.kernel.org, Samuel Ortiz , Pawel Moll , Ian Campbell , Lee Jones , Nicolas Ferre , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, Rob Herring , Alexandre Belloni , Kumar Gala , Jean-Christophe Plagniol-Villard , Andrew Victor , linux-arm-kernel@lists.infradead.org, Mark Yao List-Id: devicetree@vger.kernel.org On Mon, 6 Oct 2014 14:40:15 +0200 Thierry Reding wrote: > On Mon, Oct 06, 2014 at 02:25:38PM +0200, Boris Brezillon wrote: > > On Mon, 6 Oct 2014 13:01:16 +0200 Thierry Reding wrote: > > > On Wed, Oct 01, 2014 at 04:53:07PM +0200, Boris Brezillon wrote: > > > [...] > > > > diff --git a/arch/arm/boot/dts/sama5d3xdm.dtsi b/arch/arm/boot/dts/sama5d3xdm.dtsi > [...] > > > > + backlight = <&backlight>; > > > > + power-supply = <&panel_reg>; > > > > + #address-cells = <1>; > > > > + #size-cells = <0>; > > > > + status = "disabled"; > > > > + > > > > + port@0 { > > > > + #address-cells = <1>; > > > > + #size-cells = <0>; > > > > + > > > > + panel_input: endpoint@0 { > > > > + reg = <0>; > > > > + remote-endpoint = <&hlcdc_panel_output>; > > > > + }; > > > > }; > > > > > > There's no support for OF graphs in simple-panel, so this is unused, > > > isn't it? > > > > Actually I use it in my atmel_hlcdc_ouput implementation to figure out > > the link between a panel and a device connected on the RGB/DPI bus. > > That's kind of weird and one of the reasons why I can't make myself like > the OF graph bindings. It requires drivers for one device to reach into > the device tree node of some other device and look for content. Or put > another way, a DT node for a panel that works on one platform doesn't > work on another because the display controller needs additional DT > content that isn't required by the original binding for the panel. I also have a working POC of a DPI bus implementation (with DPI support in panel-simple driver). This is a solution I developed to provide a generic DPI implementation in my HLCDC driver and rely on generic external implementations for slave devices (panels, encoders, ...). But, IIRC, Laurent was not in favor of a bus approach because the DPI bus is just a data bus and not a control bus. Anyway, I'll clean it up and post an RFC. -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com