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=-4.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 7CD10C169C4 for ; Thu, 31 Jan 2019 15:16:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 50B5B2086C for ; Thu, 31 Jan 2019 15:16:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="va8SpPi5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729464AbfAaPQl (ORCPT ); Thu, 31 Jan 2019 10:16:41 -0500 Received: from mail-lj1-f194.google.com ([209.85.208.194]:41564 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725787AbfAaPQl (ORCPT ); Thu, 31 Jan 2019 10:16:41 -0500 Received: by mail-lj1-f194.google.com with SMTP id k15-v6so2982999ljc.8; Thu, 31 Jan 2019 07:16:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=g2Bddw9yWGmXhFqz/7OEXh1b72pF6L3F5FhPW/3Gc6s=; b=va8SpPi5jIw1gDmJWbSDlmWtPmvQ4OyEHSbss3ud7DJYxhTKxQ5t8cKY28SZrXknb2 JjvCly82ecf0/D4q2816fxxQfEiY33zbEPPo2gLTCvS1lq1j5s565TQ06+VCus6LpGGn 8H92j2PIQUzhm3ulPkh7RAy774YO8FQ0weEvBFn0452FncLyVCOEE/+5fTVThu/cOIyf w1mtGqo1SZhvlYnTLMXwaxw03F5akSD5iUYtkQfoTgZCQ+/7qMfFi0XMijAhB3YWgrP6 5usLi50tvSR8wEIT40z7SHeBIQIv7h44bcI5T6etvWj5H2qHsTY3xnPnBOp/i7Txn/xt X/DQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=g2Bddw9yWGmXhFqz/7OEXh1b72pF6L3F5FhPW/3Gc6s=; b=HjUc3L4S7j5gAue3YpTqOPV0EibE/h2jhLvMZa8tAIR69hv2E5rjHxrS95KXvltkFk FL7SgJGcPGmtgZCKikrV9/YTAwRbIRTSqVMzBJww0gC//sraz+jUb57iYIoEm8Wd/U/7 Pz+laB9Jd7aVMreWeDCgKUf9jBeKORY/RqSFe/26lvUnsug1nuFmdhEVSpzjwMKms/q5 4TMzxoYTxwgouPcWHf97UeiTWrCYtrOvQEZfENbIF20ok28kO7vS/Aqse74mV30ZK3v/ qWPC5ij+4mQ9KoMxWl1wnknu41X1OtgOOhEkDGK6HHEH6D/ssJPIpLIrJVWNW6AhYicJ ORtQ== X-Gm-Message-State: AJcUukfMNc92kEjuOVI98dsoLEgAJM3qFFvAjqXsCKPHgzuyC40v+ijf ddF6N4hlKLXezwa05SAPXYdsDJ1l X-Google-Smtp-Source: ALg8bN5Ywi9qWSO1NiN83R12MyxkyBFZER50ni4BuMH6z8x3vAsons15IIwes1ECi6qOhmUTeUydlA== X-Received: by 2002:a2e:681a:: with SMTP id c26-v6mr28122170lja.175.1548947798135; Thu, 31 Jan 2019 07:16:38 -0800 (PST) Received: from [192.168.2.145] (ppp91-79-175-49.pppoe.mtu-net.ru. [91.79.175.49]) by smtp.googlemail.com with ESMTPSA id p77-v6sm927119lja.0.2019.01.31.07.16.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Jan 2019 07:16:37 -0800 (PST) Subject: Re: [PATCH V8 2/5] i2c: tegra: Add Bus Clear Master Support To: Sowjanya Komatineni , thierry.reding@gmail.com, jonathanh@nvidia.com, mkarthik@nvidia.com, smohammed@nvidia.com, talho@nvidia.com Cc: linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org References: <1548915387-28826-1-git-send-email-skomatineni@nvidia.com> <1548915387-28826-2-git-send-email-skomatineni@nvidia.com> From: Dmitry Osipenko Message-ID: <5aacf5c7-13bb-c8ae-d8f2-259b0c3f3c81@gmail.com> Date: Thu, 31 Jan 2019 18:16:36 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <1548915387-28826-2-git-send-email-skomatineni@nvidia.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 31.01.2019 9:16, Sowjanya Komatineni пишет: > Bus clear feature of tegra i2c controller helps to recover from > bus hang when i2c master loses the bus arbitration due to the > slave device holding SDA LOW continuously for some unknown reasons. > > Per I2C specification, the device that held the bus LOW should > release it within 9 clock pulses. > > During bus clear operation, Tegra I2C controller sends 9 clock > pulses and terminates the transaction with STOP condition. > Upon successful bus clear operation, bus goes to idle state and > driver retries the transaction. > > Signed-off-by: Sowjanya Komatineni > --- > [V5/V6/V7/V8]: Same as V4 > [V4]: Added I2C Bus Clear support patch to this version of series. > I haven't checked all of the bits in this patch, but at least -EAGAIN should work as expected on older Tegra's: Reviewed-by: Dmitry Osipenko