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

[shabeerbadarudh]

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>;

    keep-power-in-suspend;

    enable-sdio-wakeup;

    non-removable;

    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)

Regards,

Shabeer

[igorpadykov]

Hi Shabeer

one can look at attached patches for i.MX6SL EVK.

Best regards

igor

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[shabeerbadarudh]

Hi igorpadykov,

Thanks for your response!!.

We have applied the attached kernel patches but it  couldn't set  1.8v configuration for usdhc2 of i.MX6 SOLO. It shows some messages "mmc0: Ignore 3.3V voltage request on 1.8V only port".

So please clear my doubts.

1. We have used a different u-boot (U-boot 2004.01), the "struct fsl_esdhc" structure has different implementation, can't apply the u-boot patches. Does the u-boot patches is mandatory one?

2. We have not configured SD2_VSELECT pad. Does this pad is required for 1.8v configuration.

3. The kernel boot log message is attached, do you have any suggestion for find out the issue?

Best Regards,

Shabeer.