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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A7FA0EB64DA for ; Sat, 8 Jul 2023 12:53:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EE5C110E0D9; Sat, 8 Jul 2023 12:53:16 +0000 (UTC) Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) by gabe.freedesktop.org (Postfix) with ESMTPS id DEAD610E0D9 for ; Sat, 8 Jul 2023 12:53:13 +0000 (UTC) Received: from [127.0.0.1] (p578adb1c.dip0.t-ipconnect.de [87.138.219.28]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 6DA778634E; Sat, 8 Jul 2023 14:53:09 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1688820790; bh=j1VW+YqlIr6gMFRVJdYCG+mHS0tWNFRYQxRf8AA6Y/I=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Oxql7ehPge5nSg6NraVob/joMOb/2cAVw3vB0uEHQ1ScHrHed0M7PRSzq+sIPfV67 R8025mKCQmdpsjSbfN/8DJ1sg5XNLXuc6e2QEpGkJI/cgNF1sKjEg33HPPouYy3K4W Shkb6BshWHHlHeFTDmhosGRbOeOovJsMK4hIbKDNyUrDnUuuWs7EixbfKFON/IJ/RV +G/oZNo2IBw/ny1zgxBqKImVocbPPbj6kz7z6fP07zTADqgoysLPbIgCUi5FfCapLA MGI0hqCQ/Ldt2aLEksXjL1BMNBkQDERKA4ZD2hQi4qpSB8tU2DZDg/JFGb5o+2Q32V tM84W++UvBCDQ== Message-ID: <8b0ae1d1-c769-1f55-0452-4bbc62da133b@denx.de> Date: Sat, 8 Jul 2023 13:07:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [PATCH v4 3/3] drm/panel-fannal-c3004: Add fannal c3004 DSI panel To: Paulo Pavacic References: <20230607151127.1542024-1-pavacic.p@gmail.com> <20230607151127.1542024-4-pavacic.p@gmail.com> <0d43e653-32cd-b25e-40fa-6f0571048467@denx.de> Content-Language: en-US From: Marek Vasut In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Virus-Scanned: clamav-milter 0.103.8 at phobos.denx.de X-Virus-Status: Clean X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: neil.armstrong@linaro.org, conor+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, robh+dt@kernel.org, Jagan Teki , sam@ravnborg.org, Maya Matuszczyk Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 7/7/23 17:26, Paulo Pavacic wrote: > Hello Marek, Hi, > čet, 6. srp 2023. u 17:26 Marek Vasut napisao je: >> >> On 7/6/23 17:18, Paulo Pavacic wrote: >>> Hello Linus, >>> >>> čet, 22. lip 2023. u 10:22 Linus Walleij napisao je: >>>> >>>> On Wed, Jun 21, 2023 at 5:09 PM Paulo Pavacic wrote: >>>> >>>>> A lot of modifications to st7701 are required. I believe it would >>>>> result in a driver that doesn't look or work the same. e.g compare >>>>> delays between initialization sequences of panel-fannal-c3004 and >>>>> panel-st7701. I think it would be optimal to create st7701s driver and >>>>> have special handling for st7701s panels. If there was a flag for >>>>> whether panel is st7701 or st7701s it would end up looking like a >>>>> mess. >>>> >>>> What matters is if the original authors of the old st7701 driver are >>>> around and reviewing and testing patches at all. What we need is >>>> active maintainers. (Added Jagan, Marek & Maya). >>>> >>>> I buy the reasoning that the st7701s is perhaps substantially different >>>> from st7701. >>>> >>>> If st7701s is very different then I suppose it needs a separate driver, >>>> then all we need to to name the driver properly, i.e. >>>> panel-sitronix-st7701s.c. >>> >>> I had in person talk with Paul Kocialkowski and I have concluded that >>> this is the best solution. >>> I believe I should rename it to st7701s due to the hardware changes. I >>> would like to create V5 patch with driver renamed to st7701s. >>> Please let me know if you agree / disagree. >> >> If I recall it right, the ST7701 and ST7701S are basically the same >> chip, aren't they ? > > I'm currently exploring all the differences. There aren't a lot of > differences, but there are some. > So far I can see that default register values are different, new > previously unused registers are now used and there has been some > reordering of how info is placed in registers [1] (data bits are in > different order). Moreover, instructions to some commands have been > changed and meaning of what data bits mean [2][3]. Also, new features > have been added [2]; there is now PCLKS 3 for example. > > You can see few differences in following images. Same images were > attached in this mail: > [1] https://ibb.co/NmgbZmy - GAMACTRL_st7701.png > [2] https://ibb.co/G79y235 - PCLKS2.png Ouch. I wonder if this is still something that can be abstracted out with some helper accessor functions like: if (model == ST7701) write something else write the other layout Or whether it makes sense to outright have a separate driver. The later would introduce duplication, but maybe that much duplication is OK.