From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751607AbdBFL3i (ORCPT ); Mon, 6 Feb 2017 06:29:38 -0500 Received: from smtp.domeneshop.no ([194.63.252.55]:54978 "EHLO smtp.domeneshop.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750953AbdBFL3h (ORCPT ); Mon, 6 Feb 2017 06:29:37 -0500 Subject: Re: [PATCH 0/2] drm/panel: Add support for the Sitronix ST7789V To: Maxime Ripard References: <2db19e6e-9857-1c92-dc77-c6b862cc771f@tronnes.org> <20170206103938.3yghvugiwpzkij6r@lukather> Cc: Rob Herring , Mark Rutland , Thierry Reding , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org From: =?UTF-8?Q?Noralf_Tr=c3=b8nnes?= Message-ID: Date: Mon, 6 Feb 2017 12:29:31 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170206103938.3yghvugiwpzkij6r@lukather> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Den 06.02.2017 11.39, skrev Maxime Ripard: > Hi Noralf, > > On Fri, Feb 03, 2017 at 07:48:51PM +0100, Noralf Trønnes wrote: >> Den 03.02.2017 10.59, skrev Maxime Ripard: >>> Hi, >>> >>> Here is an attempt at supporting the ST7789V LCD controller from Sitronix. >> What happens if there's another panel driven by ST7789V that needs >> a different controller initialization? > You know those panels / controllers much better than I do, but why > would that be the case? > >> Maybe it's better to name it after the panel, not the controller. > I guess you could also use that panel directly without the controller? A controller can drive many different panels that can require different initializations. I faced that with staging/fbtft, when I wrote controller drivers having initialization code, and then came across displays with the same controller but with a different initialization. Trying to write controller drivers for these controllers is very difficult with all the possible permutations. On top of that we have those undocumented commands/registers. Some panels come with embedded controllers, in which case it makes sense to write a driver for the panel. But if the panel and controller are separate, then I don't know. Maybe the chance of coming across two uncompatible ST7789V and panel combinations in drm/panel is extremly low. Noralf.