From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhoujie Wu Subject: Re: [EXT] Re: [PATCH] mmc: sdhci-xenon: add gpio hard reset support Date: Wed, 16 Aug 2017 15:46:53 -0700 Message-ID: <5994CB5D.5080509@marvell.com> 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="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx0a-0016f401.pphosted.com ([67.231.148.174]:48057 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752517AbdHPWrC (ORCPT ); Wed, 16 Aug 2017 18:47:02 -0400 In-Reply-To: Sender: linux-mmc-owner@vger.kernel.org List-Id: linux-mmc@vger.kernel.org To: Shawn Lin Cc: linux-mmc@vger.kernel.org, ulf.hansson@linaro.org, adrian.hunter@intel.com, zmxu@marvell.com, jszhang@marvell.com, nadavh@marvell.com, xigu@marvell.com, dingwei@marvell.com, kostap@marvell.com, hannah@marvell.com, hongd@marvell.com, dougj@marvell.com, ygao@marvell.com, liuw@marvell.com, gregory.clement@free-electrons.com, thomas.petazzoni@free-electrons.com Hi , On 08/15/2017 05:32 PM, 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. > > i.e: > > vcc_sd: regulator { > compatible = "regulator-gpio"; > regulator-name = "vcc_sd"; > regulator-min-microvolt = <3300000>; > regulator-max-microvolt = <3300000>; > > gpios = <&gpio1 23 GPIO_ACTIVE_HIGH>; > enable-active-high; > }; > > &sdhci { > vmmc-supply = <&vcc_sd>; > } > > I tried to use the vmmc-supply regulator before I submit this patch, I met a issue in this case. sdhci_set_power_reg will be called instead, and I saw mmc_regulator_set_ocr do enabled the regulator, after that SW will set 0xf to power controller register, but the register is self-cleared to 0 soon which lead to later cmd timeout all the time. Have you ever met similar issue before? >>> >>>> Add gpio hard reset feature for this purpose. >>>> > >> >> >> >> >