Currently sdhci-esdhc-imx.c sets SDHCI_QUIRK2_NO_1_8_V if no 100MHz/200MHz pinctrl configurations are present in order to prevent the stack from choosing high speed modes. This does work for SD cards quite well, since 1.8V matches all higher speed modes, and all lower speed modes run with 3.3V. However, when running a eMMC on 1.8V only, this causes issues: If vqmmc-supply is set to 1.8V only, and the driver at the same time sets SDHCI_QUIRK2_NO_1_8_V, the stack has troubls selecting a valid mode and continuously prints: mmc1: Switching to 3.3V signalling voltage failed There are already board device trees which work around this by not setting vqmmc-supply, e.g. arch/arm/boot/dts/imx6qdl-sr-som-ti.dtsi. Introducing a new quirk was the only way which I came up with, but maybe there is a better way to prevent higher speed modes while allowing 1.8V eMMC? Stefan Agner (3): mmc: sdhci-esdhc-imx: get rid of support_vsel mmc: sdhci: add quirk to prevent higher speed modes mmc: sdhci-esdhc-imx: prevent stack from using higher speed modes drivers/mmc/host/sdhci-esdhc-imx.c | 12 ++++-------- drivers/mmc/host/sdhci.c | 8 ++++++++ drivers/mmc/host/sdhci.h | 2 ++ include/linux/platform_data/mmc-esdhc-imx.h | 2 -- 4 files changed, 14 insertions(+), 10 deletions(-) -- 2.18.0 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
