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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 0AF83C11F69 for ; Wed, 30 Jun 2021 10:21:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E262161407 for ; Wed, 30 Jun 2021 10:21:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234159AbhF3KYR (ORCPT ); Wed, 30 Jun 2021 06:24:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55870 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234120AbhF3KYQ (ORCPT ); Wed, 30 Jun 2021 06:24:16 -0400 Received: from mail-ej1-x62f.google.com (mail-ej1-x62f.google.com [IPv6:2a00:1450:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66410C06175F for ; Wed, 30 Jun 2021 03:21:47 -0700 (PDT) Received: by mail-ej1-x62f.google.com with SMTP id l24so3311307ejq.11 for ; Wed, 30 Jun 2021 03:21:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amarulasolutions.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=pRd6pcMdNebp+pN5HMRRgF54QAuGLj+u/RVF3wGoo18=; b=ATKO+gmm4xEc6zgEP7S6/Z+diDreHx/sUxeSyYuhtT7zwrtOsR0ZtMcFTiDUA8ZlOu JX/hOLoFLa8O29+0/knSdMZQB3/yImsXIvJjt86mYMGf9u0OexWOBu65f8ZHwyBpAxzX Cu5psuErLV+VoTcyFiT/zThG5MBdf/A632cx8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=pRd6pcMdNebp+pN5HMRRgF54QAuGLj+u/RVF3wGoo18=; b=FPeKJjrvgiT/ENuwPy0MF17x9BymYg7dz83H06etfpzef3XAvZAjLWoxzigV6FFiix nrLS5GA/pcnbbVDPGi11Z84EfVh4SK8Ha8dl0TgmF8azsnyB1dvDmO6qnuF4h+EYVkmr boL6VLrDTj2ytvQQaYJZQ4p9sG+4aPEXYkFa1GGeFX4PcR5QkPP1pDQYoSP3S6uBZDLm 0gGh8FOFB+WG0Ex/d0RbuEV7OpyQMt5qaDPKyF1b8sQ3Fg4C5Nbrrsg077CeBnnpS8IU vAVmAhkf7UtO33hVlBN833GY3/H0VGKKmE585bRgaPL4M3rwOBahYIX2bzVpnqBrB99n EvWw== X-Gm-Message-State: AOAM531QPlpwms2a2feAfvsZ/icKnqHZkamohnsA0weyjmITHYlSKvQ/ bLykelkfOjMPHXCh0vLLgiR7TWOqehjNGVBqUiZTHA== X-Google-Smtp-Source: ABdhPJywNEi1yzvhH5/eMxuTSgQsZfHFd6bpKgnli8ZWpww+T6iw62Wvl6+Irx61qHcOCFQlQ5wjQ3GqF0XI0jyTfjM= X-Received: by 2002:a17:906:bb10:: with SMTP id jz16mr31357635ejb.252.1625048505958; Wed, 30 Jun 2021 03:21:45 -0700 (PDT) MIME-Version: 1.0 References: <20210621072424.111733-1-jagan@amarulasolutions.com> <20210621072424.111733-3-jagan@amarulasolutions.com> <2decfea3-3659-2a3b-7706-326c97f57f8e@canonical.com> <3aa47f60-94ab-cf0f-3777-3a872dd0e6d4@kontron.de> In-Reply-To: <3aa47f60-94ab-cf0f-3777-3a872dd0e6d4@kontron.de> From: Jagan Teki Date: Wed, 30 Jun 2021 15:51:34 +0530 Message-ID: Subject: Re: [RFC PATCH 2/9] drm: bridge: Add Samsung SEC MIPI DSIM bridge driver To: Frieder Schrempf , Daniel Vetter , Laurent Pinchart Cc: Krzysztof Kozlowski , Fabio Estevam , Michael Tretter , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , Peng Fan , Francis Laniel , Matteo Lisi , Neil Armstrong , linux-amarula , Tomasz Figa , linux-kernel , Robert Foss , Andrzej Hajda , DRI mailing list , Milco Pratesi , Anthony Brandon , linux-phy@lists.infradead.org, Fancy Fang , Shawn Guo , Sascha Hauer , "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" , NXP Linux Team , "marex@denx.de" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Frieder, Thanks for sharing the details. On Mon, Jun 28, 2021 at 1:49 PM Frieder Schrempf wrote: > > Hi Jagan, > > On 24.06.21 10:30, Krzysztof Kozlowski wrote: > > On 24/06/2021 04:48, Fabio Estevam wrote: > >> Hi Jagan/Laurent, > >> > >> On Wed, Jun 23, 2021 at 7:23 PM Laurent Pinchart > >> wrote: > >> > >>> Looking at the register set, it seems to match the Exynos 5433, > >>> supported by drivers/gpu/drm/exynos/exynos_drm_dsi.c. Can we leverage > >>> that driver instead of adding a new one for the same IP core ? > >> > >> Yes. there was an attempt from Michael in this direction: > >> https://eur04.safelinks.protection.outlook.com/?url=3Dhttps%3A%2F%2Fpa= tchwork.kernel.org%2Fproject%2Fdri-devel%2Fcover%2F20200911135413.3654800-1= -m.tretter%40pengutronix.de%2F&data=3D04%7C01%7Cfrieder.schrempf%40kont= ron.de%7C52db05459ef0462d5a9b08d936eab1ba%7C8c9d3c973fd941c8a2b1646f3942daf= 1%7C0%7C0%7C637601203901391193%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAi= LCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=3DLTYk9kpUe= B9bgfRITQT6wIij3XTOIk37AHXbzQ2UI4Y%3D&reserved=3D0 > > > > That's the proper direction (maybe as Marek suggested - sharing common > > code like for Analogix DP), not duplicating a driver. > > > > Just to make sure that you are aware of the previous patches and discussi= ons here are some additional pointers: > > * i.MX8MM glue code from Marek (+ Cc): [1] > * DPHY driver from Marek: [2] > * General discussion about driver implementation: [3] > * Daniel's (+ Cc) suggested direction to move forward: [4] It Looks like Daniel's suggestion is to have a common bridge driver without sharing a code between platforms. It makes sense and clean but the key issues lie on the exynos side, the exynos drm drives require potential changes and tests, which indeed are hard but possible - IMHO. However there is another issue with component_ops the i.MX8M side MXSFB doesn't use any component_ops but the exynos are fully component aware. > > It looks like you already did a fork of the Exynos driver, so your approa= ch might be generally in line with what Daniel suggested. I did use PMS computation from exynos and reference driver from imx8 tree. Last 2 days I worked on exynos_drm_dsi.c (with some additions) and converted a bridge driver and it worked on my i.MX8MM platform. Right now, I'm checking the possible implementations and will come back to my approach for further comments. Jagan.