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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A161FC4332F for ; Thu, 8 Dec 2022 23:24:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229677AbiLHXYH (ORCPT ); Thu, 8 Dec 2022 18:24:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229936AbiLHXXU (ORCPT ); Thu, 8 Dec 2022 18:23:20 -0500 Received: from mail-io1-xd30.google.com (mail-io1-xd30.google.com [IPv6:2607:f8b0:4864:20::d30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A97AF6ACCA for ; Thu, 8 Dec 2022 15:22:08 -0800 (PST) Received: by mail-io1-xd30.google.com with SMTP id i83so1189315ioa.11 for ; Thu, 08 Dec 2022 15:22:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=kbpMQ63Zd0ddTl917YQAEJDL2fT9g2XYtpQwPSl/m6E=; b=oZjo3h0jiJm+5LuEJLHVzKLTtbsfV4Yuzhhxd/0ah+FUxmwHzdKXsVKAZkW+Pt1cP7 bZJht87h69mLBsd1Tr8S5xNbfe5pJ8QSZtXBGHnH6b9s6QFQmWTOdTfyGBDZxslciDBi xOg+nIOw+X5W+tU+P2FkZ0ukmTYoQuwun0OgE= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=kbpMQ63Zd0ddTl917YQAEJDL2fT9g2XYtpQwPSl/m6E=; b=Y8zkKYLRjfcwsKzbGii5+F7UaDwfTl81XVQrOWyeFW8rObvPYoD2FSwiGRm8rCX3w2 NmhuKKknZXsF6wZ/eVuSA6qKwnXDGXXzc0Wo7sEfa1T+ULXLahSu9MTh/ZUVoVYp0BiI 6aGPjKSdAyBISuKSv+WnGPfVdx0ik3k6PLsEzGz5NtXUuawIT+L8YQWWeLqOLAvKBcfg xp00XpeZabsEJcu4VIlzfdOGiWZTNYFcEN7ZpIX0kGkQdsKjm1aEO8AnK1kX2mXva/C7 Ab4qA0ONBjV03UtqpkAUvCNhTHP1XEESz2z7bBUZmpt6pHWReTkIfzN1LIy95zvmXy2x GwFA== X-Gm-Message-State: ANoB5plrk/kFi9pO1AWsLsfySU+Z7cDpsnWYhqGKRsGgH5b56xlNCaTY BkGSzC7sYPxPn7rbO8+0mRvGpA== X-Google-Smtp-Source: AA0mqf7R4a0/39caWEYz1Aqubo3foxnMQIfA4QfNcQ9VQeaAtG5do3746c/qrqrZlXYDXMfVE8x12A== X-Received: by 2002:a5d:8593:0:b0:6bc:d712:8bbc with SMTP id f19-20020a5d8593000000b006bcd7128bbcmr2168029ioj.4.1670541728078; Thu, 08 Dec 2022 15:22:08 -0800 (PST) Received: from localhost (30.23.70.34.bc.googleusercontent.com. [34.70.23.30]) by smtp.gmail.com with UTF8SMTPSA id o7-20020a0566022e0700b006a49722dc6dsm7371iow.11.2022.12.08.15.22.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 08 Dec 2022 15:22:07 -0800 (PST) Date: Thu, 8 Dec 2022 23:22:07 +0000 From: Matthias Kaehlcke To: Douglas Anderson Cc: Bjorn Andersson , Dmitry Torokhov , swboyd@chromium.org, linux-arm-msm@vger.kernel.org, linux-input@vger.kernel.org, Yunlong Jia , Konrad Dybcio , Andy Gross , Krzysztof Kozlowski , Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/5] arm64: dts: qcom: sc7180: Bump up trogdor ts_reset_l drive strength Message-ID: References: <20221208192006.1070898-1-dianders@chromium.org> <20221208111910.1.I39c387f1e3176fcf340039ec12d54047de9f8526@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20221208111910.1.I39c387f1e3176fcf340039ec12d54047de9f8526@changeid> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 08, 2022 at 11:20:02AM -0800, Douglas Anderson wrote: > On at least one board (pazquel360) the reset line for the touchscreen > was scoped and found to take almost 2 ms to fall when we drove it > low. This wasn't great because the Linux driver for the touchscreen > (the elants_i2c driver) thinks it can do a 500 us reset pulse. If we > bump the drive strength to 8 mA then the reset line went down in ~421 > us. > > NOTE: we could apply this fix just for pazquel360, but: > * Probably other trogdor devices have similar timings and it's just > that nobody has noticed it before. > * There are other trogdor boards using the same elan driver that tries > to do 500 us reset pulses. > * Bumping the drive strength to 8mA across the board won't hurt. This > isn't a high speed signal or anything. > > Signed-off-by: Douglas Anderson Reviewed-by: Matthias Kaehlcke