From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jisheng Zhang Subject: Re: [EXT] Re: [PATCH] mmc: sdhci-xenon: add gpio hard reset support Date: Wed, 16 Aug 2017 10:44:29 +0800 Message-ID: <20170816104429.00c35ca9@xhacker> References: <1502749156-22798-1-git-send-email-zjwu@marvell.com> <3696b751-68cc-6c11-bb7d-af7d6e6a5681@rock-chips.com> <59937848.2040901@marvell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]:55410 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752956AbdHPCtc (ORCPT ); Tue, 15 Aug 2017 22:49:32 -0400 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Shawn Lin , Zhoujie Wu , hannah@marvell.com Cc: linux-mmc@vger.kernel.org, ulf.hansson@linaro.org, adrian.hunter@intel.com, zmxu@marvell.com, nadavh@marvell.com, xigu@marvell.com, dingwei@marvell.com, kostap@marvell.com, hongd@marvell.com, dougj@marvell.com, ygao@marvell.com, liuw@marvell.com, gregory.clement@free-electrons.com, thomas.petazzoni@free-electrons.com On Wed, 16 Aug 2017 08:32:09 +0800 Shawn Lin wrote: > Hi > > On 2017/8/16 6:40, Zhoujie Wu wrote: > > Hi Shawn, > > >> ---------------------------------------------------------------------- > >> Hi > >> > >> On 2017/8/15 6:19, Zhoujie Wu wrote: > >>> On some platforms, like armada3700, SD card need to > >>> do hard reset by gpio toggling to make it work properly > >>> after warm reset the board. > >> > >> I don't get this that SD card need to do hard reset... > >> > >> I assume what you talk about is either for eMMC or a power-cycle > >> for SD card. > > > > The subject of the patch confused you. What I want is a power-cycle for > > the SD card. The gpio is used to enable/disable the vdd power supply > > for sd card. > > Actually on a3700, when warm reset the board, their is no power-cycle > > for SD card, which will lead sd card can't response correct ocr and > > never set S18A unless a power-cycle. > > This is the purpose I submit this patch. > > > > Well, if that is the case, I suggest you to use regulator-gpio. Oh yes! If the gpio is for power, why not make use of regulator? then except the dts, we don't need do anything.