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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 4907DC6778C for ; Thu, 5 Jul 2018 11:43:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0101E24048 for ; Thu, 5 Jul 2018 11:43:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=agner.ch header.i=@agner.ch header.b="lGEeMn58" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0101E24048 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=agner.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753999AbeGELnu (ORCPT ); Thu, 5 Jul 2018 07:43:50 -0400 Received: from mail.kmu-office.ch ([178.209.48.109]:38476 "EHLO mail.kmu-office.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753848AbeGELns (ORCPT ); Thu, 5 Jul 2018 07:43:48 -0400 Received: from webmail.kmu-office.ch (unknown [IPv6:2a02:418:6a02::a3]) by mail.kmu-office.ch (Postfix) with ESMTPSA id 476835C16B5; Thu, 5 Jul 2018 13:43:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=agner.ch; s=dkim; t=1530791027; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=VyopVX8tcOCX1GCLUUrigB0jzRVuz1Ro2KwZ6t7W3l0=; b=lGEeMn58QBUO8B+HN2h7RWmkYlc5kV6I9jxX6sMVQDoeg3IfjLtYPMQRdF6xryOHY4Fn9y 5kRI1BiOH5le2YoEjLoqk4Couux0o5JxUP8JmlRUiyS7kKX1HP+hm9p8uDiWdCvuxSfFT2 bZsK9SlMFuiyM+khmRT3thvecBfcXFg= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Date: Thu, 05 Jul 2018 13:43:47 +0200 From: Stefan Agner To: Ulf Hansson Cc: Adrian Hunter , Fabio Estevam , Haibo Chen , Aisheng Dong , Michael Trimarchi , Russell King , linux-mmc@vger.kernel.org, Linux Kernel Mailing List Subject: Re: [PATCH v2] mmc: sdhci-esdhc-imx: allow 1.8V modes without 100/200MHz pinctrl states In-Reply-To: References: <20180704150745.21003-1-stefan@agner.ch> Message-ID: X-Sender: stefan@agner.ch User-Agent: Roundcube Webmail/1.3.4 X-Spamd-Result: default: False [-0.10 / 15.00]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; TAGGED_RCPT(0.00)[kernel]; MIME_GOOD(-0.10)[text/plain]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_SEVEN(0.00)[9]; FROM_EQ_ENVFROM(0.00)[]; DKIM_SIGNED(0.00)[]; TO_DN_SOME(0.00)[]; RCVD_COUNT_ZERO(0.00)[0]; ASN(0.00)[asn:29691, ipnet:2a02:418::/29, country:CH]; RCVD_TLS_ALL(0.00)[]; BAYES_HAM(-0.00)[38.09%]; ARC_NA(0.00)[] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05.07.2018 13:23, Ulf Hansson wrote: > On 4 July 2018 at 17:07, Stefan Agner wrote: >> If pinctrl nodes for 100/200MHz are missing, the controller should >> not select any mode which need signal frequencies 100MHz or higher. >> To prevent such speed modes the driver currently uses the quirk flag >> SDHCI_QUIRK2_NO_1_8_V. This works nicely for SD cards since 1.8V >> signaling is required for all faster modes and slower modes use 3.3V >> signaling only. >> >> However, there are eMMC modes which use 1.8V signaling and run below >> 100MHz, e.g. DDR52 at 1.8V. With using SDHCI_QUIRK2_NO_1_8_V this >> mode is prevented. When using a fixed 1.8V regulator as vqmmc-supply >> the stack has no valid mode to use. In this tenuous situation the >> kernel continuously prints voltage switching errors: >> mmc1: Switching to 3.3V signalling voltage failed >> >> Avoid using SDHCI_QUIRK2_NO_1_8_V and prevent faster modes by >> altering the SDHCI capability register. With that the stack is able >> to select 1.8V modes even if no faster pinctrl states are available: >> # cat /sys/kernel/debug/mmc1/ios >> ... >> timing spec: 8 (mmc DDR52) >> signal voltage: 1 (1.80 V) >> ... >> >> Link: http://lkml.kernel.org/r/20180628081331.13051-1-stefan@agner.ch >> Signed-off-by: Stefan Agner > > I am fine with this. Do you want me to apply this for now, to get it tested? > Yes. > I guess its also material for stable and as fix? > I guess. We probably want to wait until it gets some more testing? > In regards to the printed warning, it sounds to me like a different > issue, which we can solve on top. Right? Yes different issue, which we can handle separately. -- Stefan