Received: by 2002:a25:ab43:0:0:0:0:0 with SMTP id u61csp8112605ybi; Thu, 6 Jun 2019 06:58:15 -0700 (PDT) X-Google-Smtp-Source: APXvYqyMPeNSSepjoJhfuwlkH45o+V6O5JxMAKYAYFJWnNWIYceENIiZQdkoFCo03hF85kJKVHRe X-Received: by 2002:a17:90a:29c5:: with SMTP id h63mr9181pjd.83.1559829495300; Thu, 06 Jun 2019 06:58:15 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1559829495; cv=none; d=google.com; s=arc-20160816; b=DY+3PfCHGv78g08e4Gek6Y0V/blJ6WnBnIp6P1bBYMo3gYbcJ48hib51ErBhX5aqv1 bVX1sltKJoS7zR9YfrGt48i2pNOBeLsoxAH13nqATy+5RJi+sgKUKAHBz0wm46EMYC2L rPDv0pEelfj0pq7rvE99aasTVzN8g3SJKYXUYn0LQBQ/vRTB1KQ4eAb2PHf/HhkFEbgD ogIQ5ujMn6rR0wlI4cgFKsevvdig0lQEDosOcB5ujZfmFiC2FtgZ6iEXpVANIOAOGXIN w384W/HaEb8jTTzzBsM3voQRMx1AXPOTrsjUM/OKt/rpJRJb9zoJ6HM9VJpblVIbLPPR v4yQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:dkim-signature:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:from:references:cc:to:subject; bh=6e3s0THa4zvwhgtfqAaZTr8O5dOGC++3FEJrroJDDAM=; b=mp5NtIUrwOAB4I19svg0DPAK6BcyTBjRBjw0p362RhtcS5AU3gbONHR5ptv1x4abKQ wTFyGkjr0TV53BJw3DFHyAGj8PWUVtz5cKMJx+ub6SQcffIN4pIM/HfEW22FN/UqJOUi pLps2htFRvXSLJd5++0S/7SwmF1AjyK/6174lTiCq2JQyMBg6PcepZFNXNr8B+Hrtyus PyPQjaZr0kUNLWTArrOqnboHAFoYkdwWkn7kWm1ZpArpxIucJalLFnIR7zLogqNFmXmz HXUZoSRf2mIrtJrJ+3HVaxa0W75Ufth4aln0JbPgwvn7R1xXPsQghkTkA+eJVKyfe9pT IC9w== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=JRbyl06C; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id g30si1860248plg.400.2019.06.06.06.57.57; Thu, 06 Jun 2019 06:58:15 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=JRbyl06C; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728086AbfFFNzw (ORCPT + 99 others); Thu, 6 Jun 2019 09:55:52 -0400 Received: from hqemgate14.nvidia.com ([216.228.121.143]:3797 "EHLO hqemgate14.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726693AbfFFNzv (ORCPT ); Thu, 6 Jun 2019 09:55:51 -0400 Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 06 Jun 2019 06:55:48 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 06 Jun 2019 06:55:50 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 06 Jun 2019 06:55:50 -0700 Received: from [10.19.65.14] (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Thu, 6 Jun 2019 13:55:47 +0000 Subject: Re: [PATCH V1] i2c: busses: tegra: Add suspend-resume support To: Dmitry Osipenko , Laxman Dewangan , Thierry Reding , Jonathan Hunter , , , CC: Shardar Mohammed , Sowjanya Komatineni , Mantravadi Karthik References: <1559195718-6693-1-git-send-email-bbiswas@nvidia.com> <9142282b-ab76-53a0-13ce-c43b8adc575f@nvidia.com> <4f14a218-332c-0263-c6c5-73a13b2446f0@gmail.com>

From: Bitan Biswas Message-ID: Date: Thu, 6 Jun 2019 06:55:44 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1559829348; bh=6e3s0THa4zvwhgtfqAaZTr8O5dOGC++3FEJrroJDDAM=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=JRbyl06CrpDeo4FzGqcdZpCzNspp06hfus947iu9KFcuwYOQb3f0J1gO2h/AsyISV 1HeUcOzb9gQF8QP5tE0ElsWfqN4nq+ipSyuJw8b+hvmHdCsfyThebGDWeCzIRk2kpq HUpvN+czSs4p0uj7yFvhL+JFYqieAW73aodH7C/RdFQK/N+tt1zCk9ebNyqj7PebXS V8N5glHmXbOenkrt5ZkwlIO+YCsDEMeqz48lXvZh3M0wzcigme8XIB+Hz/iYA0iiif FKBLFojrFDRs8plNGLBUJuyVzMcWis6knxxIkP3Omc+p1J0/Wls1gLaa6HeQBV0XtW jdBgZTDVUi0sw== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/6/19 4:52 AM, Dmitry Osipenko wrote: > 06.06.2019 8:43, Bitan Biswas =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >> >> >> On 5/31/19 5:43 AM, Dmitry Osipenko wrote: >>> 31.05.2019 11:50, Bitan Biswas =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>> >>>> >>>> On 5/30/19 4:27 AM, Dmitry Osipenko wrote: >>>>> 30.05.2019 8:55, Bitan Biswas =D0=BF=D0=B8=D1=88=D0=B5=D1=82: >>>>>> Post suspend I2C registers have power on reset values. Before any >>>>>> transfer initialize I2C registers to prevent I2C transfer timeout >>>>>> and implement suspend and resume callbacks needed. Fix below errors >>>>>> post suspend: >>>>>> >>>>>> 1) Tegra I2C transfer timeout during jetson tx2 resume: >>>>>> >>>>>> [=C2=A0=C2=A0 27.520613] pca953x 1-0074: calling pca953x_resume+0x0/= 0x1b0 @ >>>>>> 2939, parent: i2c-1 >>>>>> [=C2=A0=C2=A0 27.633623] tegra-i2c 3160000.i2c: i2c transfer timed o= ut >>>>>> [=C2=A0=C2=A0 27.639162] pca953x 1-0074: Unable to sync registers 0x= 3-0x5. -110 >>>>>> [=C2=A0=C2=A0 27.645336] pca953x 1-0074: Failed to sync GPIO dir reg= isters: -110 >>>>>> [=C2=A0=C2=A0 27.651596] PM: dpm_run_callback(): pca953x_resume+0x0/= 0x1b0 >>>>>> returns -110 >>>>>> [=C2=A0=C2=A0 27.658375] pca953x 1-0074: pca953x_resume+0x0/0x1b0 re= turned -110 >>>>>> after 127152 usecs >>>>>> [=C2=A0=C2=A0 27.666194] PM: Device 1-0074 failed to resume: error -= 110 >>>>>> >>>>>> 2) Tegra I2C transfer timeout error on jetson Xavier post resume. >>>>>> >>>>>> Signed-off-by: Bitan Biswas >>>>>> --- >>>>>> =C2=A0=C2=A0 drivers/i2c/busses/i2c-tegra.c | 24 ++++++++++++++++++= ++++++ >>>>>> =C2=A0=C2=A0 1 file changed, 24 insertions(+) >>>>>> >>>>>> diff --git a/drivers/i2c/busses/i2c-tegra.c >>>>>> b/drivers/i2c/busses/i2c-tegra.c >>>>>> index ebaa78d..f6a377f 100644 >>>>>> --- a/drivers/i2c/busses/i2c-tegra.c >>>>>> +++ b/drivers/i2c/busses/i2c-tegra.c >>>>>> @@ -1687,9 +1687,33 @@ static int tegra_i2c_remove(struct >>>>>> platform_device *pdev) >>>>>> =C2=A0=C2=A0 } >>>>>> =C2=A0=C2=A0 =C2=A0 #ifdef CONFIG_PM_SLEEP >>>>>> +static int tegra_i2c_suspend(struct device *dev) >>>>>> +{ >>>>>> +=C2=A0=C2=A0=C2=A0 struct tegra_i2c_dev *i2c_dev =3D dev_get_drvdat= a(dev); >>>>>> + >>>>>> +=C2=A0=C2=A0=C2=A0 i2c_mark_adapter_suspended(&i2c_dev->adapter); >>>>>> + >>>>>> +=C2=A0=C2=A0=C2=A0 return 0; >>>>>> +} >>>>>> + >>>>>> +static int tegra_i2c_resume(struct device *dev) >>>>>> +{ >>>>>> +=C2=A0=C2=A0=C2=A0 struct tegra_i2c_dev *i2c_dev =3D dev_get_drvdat= a(dev); >>>>>> +=C2=A0=C2=A0=C2=A0 int ret; >>>>>> + >>>>>> +=C2=A0=C2=A0=C2=A0 i2c_lock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_AD= APTER); >>>>>> +=C2=A0=C2=A0=C2=A0 ret =3D tegra_i2c_init(i2c_dev, false); >>>>>> +=C2=A0=C2=A0=C2=A0 i2c_unlock_bus(&i2c_dev->adapter, I2C_LOCK_ROOT_= ADAPTER); >>>>> >>>>> Why the locking is needed here? >>>> >>>> async resume could result in stress test issues if some client accesse= s >>>> the i2c instance. This ensures the i2c instance is locked till the >>>> initialization is complete. >>> >>> 1) This doesn't make much sense.. if client could access I2C during of >>> tegra_i2c_init execution, then what stops it to perform the access >>> before the lock is taken? >> Client resumes will start after I2C instance resume because of driver >> dependency. Since lock is the first call in i2c-tegra I believe I2C >> calls of client will not start. >=20 > You're incorrectly assuming that client can start resuming in the middle > of the controller's resume process. I2C client's resume won't start > until tegra_i2c_resume() is finished completely. That is because child > drivers are resumed only after theirs parent is ready and this is > guaranteed by the drivers core. >=20 Agreed. -regards, Bitan