Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753799AbbBOX3a (ORCPT ); Sun, 15 Feb 2015 18:29:30 -0500 Received: from mail-qa0-f44.google.com ([209.85.216.44]:45170 "EHLO mail-qa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750904AbbBOX33 (ORCPT ); Sun, 15 Feb 2015 18:29:29 -0500 MIME-Version: 1.0 In-Reply-To: <1423894668-8886-2-git-send-email-addy.ke@rock-chips.com> References: <1423828368-18456-1-git-send-email-addy.ke@rock-chips.com> <1423894668-8886-1-git-send-email-addy.ke@rock-chips.com> <1423894668-8886-2-git-send-email-addy.ke@rock-chips.com> From: Alim Akhtar Date: Mon, 16 Feb 2015 04:58:47 +0530 Message-ID: Subject: Re: [PATCH v4 1/3] mmc: dw_mmc: update clock after host reach a stable voltage To: Addy Ke Cc: Jaehoon Chung , Ulf Hansson , Olof Johansson , Andrzej Hajda , Douglas Anderson , =?UTF-8?Q?Heiko_St=C3=BCbner?= , Eddie Cai , lintao@rock-chips.com, Tao Huang , "linux-kernel@vger.kernel.org" , "linux-mmc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , linux-rockchip@lists.infradead.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2152 Lines: 70 Hi Addy, On Sat, Feb 14, 2015 at 11:47 AM, Addy Ke wrote: > As show in mmc_power_up(), in MMC_POWER_UP state, the voltage isn't > stable and we may get 'data busy' which can't be cleaned by resetting > all blocks. So we should not send command to update clock in this state. > > Signed-off-by: Addy Ke > --- > drivers/mmc/host/dw_mmc.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c > index 4d2e3c2..3472f9b 100644 > --- a/drivers/mmc/host/dw_mmc.c > +++ b/drivers/mmc/host/dw_mmc.c > @@ -1102,7 +1102,8 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios) > drv_data->set_ios(slot->host, ios); > > /* Slot specific timing and width adjustment */ > - dw_mci_setup_bus(slot, false); > + if (ios->power_mode != MMC_POWER_UP) > + dw_mci_setup_bus(slot, false); > This looks a HACK to me. If stabilizing host voltage regulator is the problem, can you try out below patch, and see if this resolve your issue? =========== [PATCH] mmc: dw_mmc: Wait for host voltage regulator to be stable Signed-off-by: Alim Akhtar --- drivers/mmc/host/dw_mmc.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c index 4d2e3c2..dc10fbb 100644 --- a/drivers/mmc/host/dw_mmc.c +++ b/drivers/mmc/host/dw_mmc.c @@ -1202,6 +1202,9 @@ static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios) } mci_writel(host, UHS_REG, uhs); + /* wait for 5ms so that host voltage regulator is stable */ + usleep_range(5000, 5500); + return 0; } =============== > if (slot->host->state == STATE_WAITING_CMD11_DONE && ios->clock != 0) > slot->host->state = STATE_IDLE; > -- > 1.8.3.2 > > -- Regards, Alim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/