From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jisheng Zhang Subject: Re: Warnings for invalid VDD (sdhci-s3c) Date: Thu, 24 Mar 2016 16:24:49 +0800 Message-ID: <20160324162449.29c9cf78@xhacker> References: <20160324155840.50474b98@xhacker> <56F3A0B7.4050509@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <56F3A0B7.4050509@samsung.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Jaehoon Chung Cc: Krzysztof Kozlowski , Ulf Hansson , Adrian Hunter , ludovic.desroches@atmel.com, "Ivan T. Ivanov" , linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org List-Id: linux-mmc@vger.kernel.org Hi, On Thu, 24 Mar 2016 17:09:27 +0900 Jaehoon Chung wrote: > Hi, > > On 03/24/2016 04:58 PM, Jisheng Zhang wrote: > > Hi, > > > > On Thu, 24 Mar 2016 16:28:56 +0900 Krzysztof Kozlowski wrote: > > > >> Hi, > >> > >> After 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD via > >> external regulator") On Trats2 board I see warnings for invalid VDD > >> value (2.8V): > >> > >> [ 3.119656] ------------[ cut here ]------------ > >> [ 3.119666] WARNING: CPU: 3 PID: 90 at > >> ../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0 > >> [ 3.119669] mmc0: Invalid vdd 0x10 > > > > Per my understanding, the wrong vdd indicates a wrong ocr, what's the voltage of > > this host's vmmc regulator? > > As i know, it's fixed-voltage with gpio on trats2. It's 2.8V. > I didn't check this entirely..need to check ocr value. > I may know the reason. the vmmc is 2.8v, then mmc_regulator_get_supply() convert the value to a ocr as 0x10. The key here is that the 2.8v is invalid in SDHCI case and isn't accepted by current sdhci driver. I dunno the elegant solution to handle this case, let's wait for sdhci maintainers idea. Thanks, Jisheng