From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755542AbdBGQq2 (ORCPT ); Tue, 7 Feb 2017 11:46:28 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:35018 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755478AbdBGQqZ (ORCPT ); Tue, 7 Feb 2017 11:46:25 -0500 Date: Tue, 7 Feb 2017 17:46:21 +0100 From: Thierry Reding To: Maxime Ripard Cc: Noralf =?utf-8?Q?Tr=C3=B8nnes?= , Rob Herring , Mark Rutland , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 0/2] drm/panel: Add support for the Sitronix ST7789V Message-ID: <20170207164621.GB28522@ulmo.ba.sec> References: <2db19e6e-9857-1c92-dc77-c6b862cc771f@tronnes.org> <20170206103938.3yghvugiwpzkij6r@lukather> <20170207153444.yc7znfkje7hm4em6@lukather> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="UHN/qo2QbUvPLonB" Content-Disposition: inline In-Reply-To: <20170207153444.yc7znfkje7hm4em6@lukather> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --UHN/qo2QbUvPLonB Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Feb 07, 2017 at 04:34:44PM +0100, Maxime Ripard wrote: > On Mon, Feb 06, 2017 at 12:29:31PM +0100, Noralf Tr=C3=B8nnes wrote: > >=20 > > Den 06.02.2017 11.39, skrev Maxime Ripard: > > > Hi Noralf, > > >=20 > > > On Fri, Feb 03, 2017 at 07:48:51PM +0100, Noralf Tr=C3=B8nnes wrote: > > > > Den 03.02.2017 10.59, skrev Maxime Ripard: > > > > > Hi, > > > > >=20 > > > > > 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? > > >=20 > > > > 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? > >=20 > > 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. > >=20 > > 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. > >=20 > > Some panels come with embedded controllers, in which case it makes > > sense to write a driver for the panel. > >=20 > > 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. >=20 > Hmm, I see. If we ever come across that case, I guess we could just > add new optional properties to override the current sequence. I think if that ever happens it's probably best to split out ST7789V code into a helper library that has functions which take parameters. Then we can simply call those functions with parameters specific to a panel from a panel-specific driver. Trying to fit all that into device tree properties is likely going to end up being really messy. Thierry --UHN/qo2QbUvPLonB Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEEiOrDCAFJzPfAjcif3SOs138+s6EFAliZ+d0ACgkQ3SOs138+ s6Es3xAAom4HErxHZY8f+7s+BvUIKZ1b91ndc+0bCS81NnDWfvc90j4/cP+YQ8VZ npT/Fnu/AKc7E7MK6Q3pZmVTVLFXg7rjpWQQS7J8z+JuxUUfB/d/Ae957znT8YOb jaFegiPellW19RmRPHncGn67yHjt27O4FrhuX4ljnm0cx4OwisPMCjnl6AEWZg0F 2SB3q9GOhL+ksn0YoQdmgrV0j1AHvKx8OFQp1QOQ5b/eXUeJOZT0DU8HIm+3IHAJ VMrlggbKnmiRu8NGcXzKhiFQa90fkBQRmhLD2mGw81SQNWHcuMTm17kX1dO2Z0Da dhC/bKENVxushZLlRXB69LERtrDEkDEl+WirY1+zj/KhZ6JR38rc2xmivkZwmLk5 kuHJ8evCfJpD3IFAj6d2F6LsaMidO8cRZfxnNlABzuD/eWAOz7WilkUv/+P9RftR moiEVhDDkBS5lwMmMDrOr+6khHc6KYOs2f3Aq+jkB6OY3L/ctSQzH21tmcKI9oL3 TLhwAvoBP9sbXaSCp/Y/N5ZIt57DYDPpD4PtuRS39l2kedhpbf3qAII66GZ4K/9N Kd/0DW5FOfJdRP3Cd+eadOJhOh91zi4hTcxZ50ZEyd+8SNc2b8GxZDQO3yB0k1on 3B97vRKNBaV9peUHcL+omWhcEOkqvug/BECQdcChnG0Tq3Iwr5o= =sToh -----END PGP SIGNATURE----- --UHN/qo2QbUvPLonB--