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SD ultra high speed configuration on custom board

Question asked by Ivan Ljubicic on Jun 28, 2016
Latest reply on Feb 8, 2017 by tom gao

Hi,

 

I need to configure ultra high speed sd card on custom board. Hardware for sd card is like sabre automotive sd card. So it has pin for switch 3V3 to 1V8. I tried with following configuration to enable ultra high speed for linux yocto kernel 3.14.28:

&usdhc4 {

    pinctrl-names = "default";

    pinctrl-0 = <&pinctrl_usdhc4_50mhz>;

    pinctrl-1 = <&pinctrl_usdhc4_100mhz>;

    pinctrl-2 = <&pinctrl_usdhc4_200mhz>;

    cd-gpios = GP_USDHC4_CD;

    vmmc-supply = <&reg_3p3v>;

    vqmmc-supply = <&reg_sd_1p8v>;

    vqmmc-1-8-v = <1>;

    bus-width = <4>;

    keep-power-in-suspend;

    enable-sdio-wakeup;

    status = "okay";

};

 

reg_sd_1p8v: regulator@4 {

            compatible = "regulator-fixed";

            reg = <0>;

            pinctrl-names = "default";

            pinctrl-0 = <&pinctrl_reg_sd_high>;

            regulator-name = "sdhci_ultra_speed";

            regulator-min-microvolt = <1800000>;

            regulator-max-microvolt = <1800000>;

            gpio = GP_USDHC4_REG;

            regulator-always-on;

        };

 

pinctrl_reg_sd_high: reg-sd-high {

        fsl,pins = <

#define GP_USDHC4_REG    <&gpio1 17 GPIO_ACTIVE_LOW>

            MX6QDL_PAD_GPIO_17__GPIO7_IO12        0x030b0 //0x1b0b0

        >;

    };

 

where vqmmc-supply is configured for 1V8 regulator with pin that switch the voltage. I am able to get high speed for sd card but not ultra high speed.

 

What is the right way to switch to ultra high speed?

 

Thanks, regards, Ivan.

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