From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Gregory CLEMENT To: Marcin Wojtas Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mmc@vger.kernel.org, ulf.hansson@linaro.org, sebastian.hesselbarth@gmail.com, andrew@lunn.ch, jason@lakedaemon.net, thomas.petazzoni@free-electrons.com, nadavh@marvell.com, alior@marvell.com, tawfik@marvell.com, jaz@semihalf.com, Subject: Re: [PATCH 2/8] mmc: sdhci-pxav3: disable clock inversion for HS MMC cards References: <1444094562-31165-1-git-send-email-mw@semihalf.com> <1444094562-31165-3-git-send-email-mw@semihalf.com> Date: Tue, 06 Oct 2015 16:44:50 +0200 In-Reply-To: <1444094562-31165-3-git-send-email-mw@semihalf.com> (Marcin Wojtas's message of "Tue, 6 Oct 2015 03:22:36 +0200") Message-ID: <87fv1o9hul.fsf@free-electrons.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: Hi Marcin, On mar., oct. 06 2015, Marcin Wojtas wrote: > From: Nadav Haklai > > According to 'FE-2946959' erratum the clock inversion option is > needed to support slow frequencies when the card input hold time > requirement is high. This setting is not required for high speed > MMC and might cause timing violation. > > Signed-off-by: Nadav Haklai > Cc: # v4.2 Seems OK too. Reviewed-by: Gregory CLEMENT Thanks, Gregory > --- > drivers/mmc/host/sdhci-pxav3.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c > index 976cddd..89a9e49 100644 > --- a/drivers/mmc/host/sdhci-pxav3.c > +++ b/drivers/mmc/host/sdhci-pxav3.c > @@ -291,6 +291,9 @@ static void pxav3_set_uhs_signaling(struct sdhci_host *host, unsigned int uhs) > uhs == MMC_TIMING_UHS_DDR50) { > reg_val &= ~SDIO3_CONF_CLK_INV; > reg_val |= SDIO3_CONF_SD_FB_CLK; > + } else if (uhs == MMC_TIMING_MMC_HS) { > + reg_val &= ~SDIO3_CONF_CLK_INV; > + reg_val &= ~SDIO3_CONF_SD_FB_CLK; > } else { > reg_val |= SDIO3_CONF_CLK_INV; > reg_val &= ~SDIO3_CONF_SD_FB_CLK; > -- > 1.8.3.1 > -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com