From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Agner Subject: [PATCH 3/3] mmc: sdhci-esdhc-imx: prevent stack from using higher speed modes Date: Thu, 28 Jun 2018 10:13:31 +0200 Message-ID: <20180628081331.13051-4-stefan@agner.ch> References: <20180628081331.13051-1-stefan@agner.ch> Return-path: In-Reply-To: <20180628081331.13051-1-stefan@agner.ch> Sender: linux-kernel-owner@vger.kernel.org To: adrian.hunter@intel.com, ulf.hansson@linaro.org Cc: fabio.estevam@nxp.com, haibo.chen@nxp.com, aisheng.dong@nxp.com, michael@amarulasolutions.com, rmk+kernel@armlinux.org.uk, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Stefan Agner List-Id: linux-mmc@vger.kernel.org If pinctrl configurations for higher speed modes are missing, the stack currently uses the no 1.8V quirk. This comes close to what we need but not exactly: E.g. if a eMMC chip uses 1.8V signaling (by specifying a 1.8V only vqmmc-supply) while not providing any 100MHz/200MHz pinctrl configurations then the SDHCI_QUIRK2_NO_1_8_V leads the stack to print signaling voltage switch failed errors continuously: mmc1: Switching to 3.3V signalling voltage failed Presumably because the stack tries to use 3.3V signaling: # cat /sys/kernel/debug/mmc1/ios ... timing spec: 8 (mmc DDR52) signal voltage: 0 (3.30 V) ... With using SDHCI_QUIRK2_NO_UHS_HS200_HS400 we prevent the stack from choosing any modes require speeds higher than 52MHz while still allowing to select modes using 1.8V at lower speeds (e.g. DDR52): # cat /sys/kernel/debug/mmc1/ios ... timing spec: 8 (mmc DDR52) signal voltage: 1 (1.80 V) ... Signed-off-by: Stefan Agner --- drivers/mmc/host/sdhci-esdhc-imx.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c index 20a420b765b3..4a1c33018072 100644 --- a/drivers/mmc/host/sdhci-esdhc-imx.c +++ b/drivers/mmc/host/sdhci-esdhc-imx.c @@ -1165,10 +1165,10 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev, * fall back to not supporting uhs by specifying no * 1.8v quirk */ - host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V; + host->quirks2 |= SDHCI_QUIRK2_NO_UHS_HS200_HS400; } } else { - host->quirks2 |= SDHCI_QUIRK2_NO_1_8_V; + host->quirks2 |= SDHCI_QUIRK2_NO_UHS_HS200_HS400; } /* call to generic mmc_of_parse to support additional capabilities */ -- 2.18.0