Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753346AbdLDHpb (ORCPT ); Mon, 4 Dec 2017 02:45:31 -0500 Received: from mail-wm0-f67.google.com ([74.125.82.67]:41000 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753161AbdLDHpZ (ORCPT ); Mon, 4 Dec 2017 02:45:25 -0500 X-Google-Smtp-Source: AGs4zMYg2fFQlRj9Mf4gTQSNp0z5ki0yJ1ZxyvvMJxn9iMV6dFT8DVM0VQeqeziiQAmIPYKoNiYiPw== Date: Mon, 4 Dec 2017 08:45:18 +0100 From: Daniel Vetter To: Linus Walleij Cc: David Lechner , Stefano Babic , Mark Rutland , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Rob Herring , "linux-kernel@vger.kernel.org" , "open list:DRM PANEL DRIVERS" Subject: Re: [PATCH v1 2/2] drm/tinydrm: add driver for ILI9225 panels Message-ID: <20171204074507.t4ksonqammnflqqg@phenom.ffwll.local> Mail-Followup-To: Linus Walleij , David Lechner , Stefano Babic , Mark Rutland , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Rob Herring , "linux-kernel@vger.kernel.org" , "open list:DRM PANEL DRIVERS" References: <1510113136-6788-1-git-send-email-david@lechnology.com> <1510113136-6788-3-git-send-email-david@lechnology.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 4.13.0-1-amd64 User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2282 Lines: 55 On Fri, Dec 01, 2017 at 03:03:30PM +0100, Linus Walleij wrote: > On Wed, Nov 8, 2017 at 4:52 AM, David Lechner wrote: > > > This adds a new driver for display panels based on the Ilitek ILI9225 > > controller. > > > > This was developed for a no-name panel with a red PCB that is commonly > > marketed for Arduino. See . > > > > I really did try very hard to find a make and model for this panel, but > > there doesn't seem to be one, so the best I can do is offer the picture > > in the link above for identification. > > > > Signed-off-by: David Lechner > > Can you explain why tinydrm is not putting its panel drivers in > drivers/gpu/drm/panel? > > I guess everybody knows except me, it's usually like that :( > > I am anyways working on a driver for Ilitek 9322 that I want > to land in drivers/gpu/drm/panel. Here is the last iteration: > https://lists.freedesktop.org/archives/dri-devel/2017-August/150205.html > Yeah I got sidetracked. OK I will get to it now. > > There are some similarities with the code I'm seeing here > but I believe they are essentially different. But it will be hard > to share code if you put the driver in the tinydrm framework. > > I guess you have also seen: > drivers/video/backlight/ili922x.c > ? > > Stefano Babic who wrote the backlight driver is available for > reviewing, so includ him in follow-ups (added to To: line). > > I'm putting you on CC as I'm rewriting it a bit after the DT > maintainers review, will try to repost ASAP. Bit more historical context: We tried using drm_panel in tinydrm, but that didn't really fit to well (as Noralf explains, tinydrm is kinda more for stand-alone panels). But tinydrm is also a bit too much midlayer-y still, so there's a bunch of todo items capture in Documentation/gpu/todo.rst. In the end we shouldn't need a special tinydrm driver, that should be covered by the usual drm helpers. Might be worth it to at least capture/summarize some of the reasons for why tinydrm doesn't use drm_panel, and what it would take to better share code (or maybe that's just a silly idea, not the first duplicated driver in drm). -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch