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How to configure mmc/sdio 1.8v on imx6 linux 3.10.17 BSP

Question asked by Shabeer Badarudheen on Oct 30, 2015
Latest reply on Nov 3, 2015 by Shabeer Badarudheen

Hi All,

We have connected QCA6134 WiFi System in Package (SiP) to usdhc2 section of i.MX6 and SDIO IO voltage is set to 1.8v. The module is detected as MMC card while boot the board, but it gives some error when loading the ath6kl WiFi driver. The ios file in the sysfs shows "vdd: 17 (2.9 ~ 3.0 V)". So how can we set the vdd to 1.8v in software. The device tree details and ios file contents given below. Do we need to modify the device tree for setting 1.8 v.


&usdhc2 {

    pinctrl-names = "default";

    pinctrl-0 = <&pinctrl_usdhc2_2>;

    bus-width = <4>;




    status = "okay";



root@imx6qdlsolo:/sys/kernel/debug/mmc0# cat ios

clock:          50000000 Hz

actual clock:   49500000 Hz

vdd:            17 (2.9 ~ 3.0 V)

bus mode:       2 (push-pull)

chip select:    0 (don't care)

power mode:     2 (on)

bus width:      2 (4 bits)

timing spec:    2 (sd high-speed)

signal voltage: 0 (3.30 V)