From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 40E311DF258; Sat, 28 Feb 2026 11:23:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772277809; cv=none; b=N/Lk7H8JbVXuKJyBWXfz4V1a+S/QCDka15HzjDgjx7/Os3QOJ/cxwFrNynjO8f89vBVvYRGY2t4noMd+nGpJqBwUB5qSUR59l28G9epdF43VWSyp33P+0LBSoIKO9PK2pf1IZPUffBgigMujWoYm+JdAaRez406XAS+TKiPKwWQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772277809; c=relaxed/simple; bh=Ls9Pq9hUIqEe6xD9d0PXw3VoiEEfRlOXlemOfB1MxqE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=AWNeehytTfGD4Bimjig7IIpcyeRNZ3yeoJo00hc8Kg66Blp3hByfEKDlOQnBP71l76lBeWLm2LA34mY31Wi1tetzTJ40aq1SaIimOJ7cgJdm7Ifa3gn9j0UWshTf02u0VnOOaKjdaLuqZ5qPhveBnVaAcbFtvF20FqYP24q5nvY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oGbphPbT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oGbphPbT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0113AC116D0; Sat, 28 Feb 2026 11:23:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772277808; bh=Ls9Pq9hUIqEe6xD9d0PXw3VoiEEfRlOXlemOfB1MxqE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=oGbphPbTclCJxctrQSS9vvXkBcKa5yfK48hNjgI9hedFWN4ooIx4ElyunFzuUTYEq 6VJem7+ZnEbd82rnaT7Hq12nn8lw/rLZcoOugL98mMdJCagWS/xXwk9UHfberzfnpw om6MM29n6pVY11zgR8zq0j18oLZ9wtbhDIqH8h2PbZtWSEC33e3jt56U6mATB5Fvv1 p2OUIJxC/fFAWCI4amw5Ml4dzCsXSYP+8WBxqog5E7jBHnNH9bUbnMtseUTCKg2ZKI GbZ7awukIefvcQ/RTu9UNiV7F476hOsMhxvnQR7MFVZKV890vqGeSV0iZ6yNwcBaek A2TxVIDbnpoFA== Message-ID: Date: Sat, 28 Feb 2026 12:23:23 +0100 Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/3] Input: add initial support for Goodix GTX8 touchscreen ICs To: Aelin Reidel , Dmitry Torokhov , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Neil Armstrong , Henrik Rydberg Cc: linux-input@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux@mainlining.org, phone-devel@vger.kernel.org, ~postmarketos/upstreaming@lists.sr.ht, Piyush Raj Chouhan , Alexander Koskovich References: <20260228-gtx8-v2-0-3a408c365f6c@mainlining.org> From: Hans de Goede Content-Language: en-US, nl In-Reply-To: <20260228-gtx8-v2-0-3a408c365f6c@mainlining.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 28-Feb-26 02:56, Aelin Reidel wrote: > These ICs support SPI and I2C interfaces, up to 10 finger touch, stylus > and gesture events. > > This driver is derived from the Goodix gtx8_driver_linux available at > [1] and only supports the GT9886 and GT9896 ICs present in the Xiaomi > Mi 9T and Xiaomi Redmi Note 10 Pro smartphones. > > The current implementation only supports Normandy and Yellowstone type > ICs, aka only GT9886 and GT9896. It is also limited to I2C only, since I > don't have a device with GTX8 over SPI at hand. Adding support for SPI > should be fairly easy in the future, since the code uses a regmap. > > Support for advanced features like: > - Firmware updates > - Stylus events > - Gesture events > - Nanjing IC support > is not included in current version. > > The current support requires a previously flashed firmware to be > present. > > As I did not have access to datasheets for these ICs, I extracted the > addresses from a couple of config files using a small tool [2]. The > addresses are identical for the same IC families in all configs I > observed, however not all of them make sense and I stubbed out firmware > request support due to this. > > I've taken a lot of inspiration from the goodix_berlin driver, but the > Berlin and GTX8 series of touchscreen ICs differ quite a bit. The driver > architecture is the same overall, i.e. the power-up sequence and general > concepts are the mostly same, but it is very clear that they are > different generations when looking at it in more detail. Right, this answers my main question about this driver which was: "why another goodix driver?" (this would be the third one). I've also compared this driver with the original goodix.c touchscreen driver (which I know well) and the protocol is somewhat closer to the original goodix.c driver then it is to goodix_berlin, but still different enough that having a separate driver is the best option IMHO. ... > From what I can tell, the evolution seems to be: > Normandy -> Yellowstone -> Berlin > since Normandy and Yellowstone are already quite different (especially > with the way checksums work) and Yellowstone has a couple of things > (checksum, fw_version) that appear similar to Berlin series ICs. You forgot the original goodix.c driver, adding that it seems the evolution is: GTx1/GTx2/GTx6 -> Normandy -> Yellowstone -> Berlin With GTx1/GTx2/GTx6 having no checksum at all (and 16 bit registers) and some of the original GTx1/GTx2/GTx6 don't have nvram for the firmware, so Linux must upload firmware every boot. Anyways I agree that these are different enough from the existing goodix and goodix_berlin drivers, so based on that (and only on that): Acked-by: Hans de Goede Regards, Hans