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=-15.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 31CFDC63777 for ; Mon, 30 Nov 2020 23:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BEF18206E9 for ; Mon, 30 Nov 2020 23:55:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="WcTh0j3I" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730690AbgK3XzX (ORCPT ); Mon, 30 Nov 2020 18:55:23 -0500 Received: from z5.mailgun.us ([104.130.96.5]:40523 "EHLO z5.mailgun.us" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729078AbgK3XzV (ORCPT ); Mon, 30 Nov 2020 18:55:21 -0500 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1606780502; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=Anjw9xAl+I8GM2JabR+FePP4NW00fcO2jMQF31wcAEE=; b=WcTh0j3InSWAItSEX/gAnUYAxegxtm/8yJU4x+BjmjrwIwqoKfz03xCjwwSNTODd7e/uIofW jmvWbRBQO7h/94WDB9rx2I5wXIUjTxKYLmZfG4tE0SR5w1zgsSgtrnzAa8jMbm/AqWtot9vn qU1EvH4Tyc/b+QFWe9RpuSbEbhQ= X-Mailgun-Sending-Ip: 104.130.96.5 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n05.prod.us-west-2.postgun.com with SMTP id 5fc5863007535c81bae3cd13 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Mon, 30 Nov 2020 23:54:24 GMT Sender: asutoshd=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id AF7FEC43464; Mon, 30 Nov 2020 23:54:23 +0000 (UTC) Received: from [192.168.8.168] (cpe-70-95-149-85.san.res.rr.com [70.95.149.85]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: asutoshd) by smtp.codeaurora.org (Postfix) with ESMTPSA id 29D16C43460; Mon, 30 Nov 2020 23:54:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 29D16C43460 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=fail smtp.mailfrom=asutoshd@codeaurora.org Subject: Re: [RFC PATCH v1] scsi: ufs: Remove pre-defined initial VCC voltage values To: Bjorn Andersson Cc: Stanley Chu , linux-scsi@vger.kernel.org, martin.petersen@oracle.com, avri.altman@wdc.com, alim.akhtar@samsung.com, jejb@linux.ibm.com, beanhuo@micron.com, cang@codeaurora.org, matthias.bgg@gmail.com, bvanassche@acm.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, nguyenb@codeaurora.org, kuohong.wang@mediatek.com, peter.wang@mediatek.com, chun-hung.wu@mediatek.com, andy.teng@mediatek.com, chaotian.jing@mediatek.com, cc.chou@mediatek.com, jiajie.hao@mediatek.com, alice.chao@mediatek.com References: <20201130091610.2752-1-stanley.chu@mediatek.com> <568660cd-80e6-1b8f-d426-4614c9159ff4@codeaurora.org> From: "Asutosh Das (asd)" Message-ID: <4335d590-0506-d920-8e7f-f0f0372780f9@codeaurora.org> Date: Mon, 30 Nov 2020 15:54:20 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.4.3 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/30/2020 3:14 PM, Bjorn Andersson wrote: > On Mon 30 Nov 16:51 CST 2020, Asutosh Das (asd) wrote: > >> On 11/30/2020 1:16 AM, Stanley Chu wrote: >>> UFS specficication allows different VCC configurations for UFS devices, >>> for example, >>> (1). 2.70V - 3.60V (By default) >>> (2). 1.70V - 1.95V (Activated if "vcc-supply-1p8" is declared in >>> device tree) >>> (3). 2.40V - 2.70V (Supported since UFS 3.x) >>> >>> With the introduction of UFS 3.x products, an issue is happening that >>> UFS driver will use wrong "min_uV/max_uV" configuration to toggle VCC >>> regulator on UFU 3.x products with VCC configuration (3) used. >>> >>> To solve this issue, we simply remove pre-defined initial VCC voltage >>> values in UFS driver with below reasons, >>> >>> 1. UFS specifications do not define how to detect the VCC configuration >>> supported by attached device. >>> >>> 2. Device tree already supports standard regulator properties. >>> >>> Therefore VCC voltage shall be defined correctly in device tree, and >>> shall not be changed by UFS driver. What UFS driver needs to do is simply >>> enabling or disabling the VCC regulator only. >>> >>> This is a RFC conceptional patch. Please help review this and feel >>> free to feedback any ideas. Once this concept is accepted, and then >>> I would post a more completed patch series to fix this issue. >>> >>> Signed-off-by: Stanley Chu >>> --- >>> drivers/scsi/ufs/ufshcd-pltfrm.c | 10 +--------- >>> 1 file changed, 1 insertion(+), 9 deletions(-) >>> >>> diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c >>> index a6f76399b3ae..3965be03c136 100644 >>> --- a/drivers/scsi/ufs/ufshcd-pltfrm.c >>> +++ b/drivers/scsi/ufs/ufshcd-pltfrm.c >>> @@ -133,15 +133,7 @@ static int ufshcd_populate_vreg(struct device *dev, const char *name, >>> vreg->max_uA = 0; >>> } >>> - if (!strcmp(name, "vcc")) { >>> - if (of_property_read_bool(np, "vcc-supply-1p8")) { >>> - vreg->min_uV = UFS_VREG_VCC_1P8_MIN_UV; >>> - vreg->max_uV = UFS_VREG_VCC_1P8_MAX_UV; >>> - } else { >>> - vreg->min_uV = UFS_VREG_VCC_MIN_UV; >>> - vreg->max_uV = UFS_VREG_VCC_MAX_UV; >>> - } >>> - } else if (!strcmp(name, "vccq")) { >>> + if (!strcmp(name, "vccq")) { >>> vreg->min_uV = UFS_VREG_VCCQ_MIN_UV; >>> vreg->max_uV = UFS_VREG_VCCQ_MAX_UV; >>> } else if (!strcmp(name, "vccq2")) { >>> >> >> Hi Stanley >> >> Thanks for the patch. Bao (nguyenb) was also working towards something >> similar. >> Would it be possible for you to take into account the scenario in which the >> same platform supports both 2.x and 3.x UFS devices? >> >> These've different voltage requirements, 2.4v-3.6v. >> I'm not sure if standard dts regulator properties can support this. >> > > What is the actual voltage requirement for these devices and how does > the software know what voltage to pick in this range? > > Regards, > Bjorn > >> -asd >> >> >> -- >> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, >> Linux Foundation Collaborative Project For platforms that support both 2.x (2.7v-3.6v) and 3.x (2.4v-2.7v), the voltage requirements (Vcc) are 2.4v-3.6v. The software initializes the ufs device at 2.95v & reads the version and if the device is 3.x, it may do the following: - Set the device power mode to SLEEP - Disable the Vcc - Enable the Vcc and set it to 2.5v - Set the device power mode to ACTIVE All of the above may be done at HS-G1 & moved to max supported gear based on the device version, perhaps? Am open to other ideas though. -asd -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, Linux Foundation Collaborative Project