Modify VIM3 Ubuntu - SD card signal voltage as 1.8V

Mater · April 24, 2025, 3:38am

Which system do you use? Android, Ubuntu, OOWOW or others?

Ubuntu

Which version of system do you use? Please provide the version of the system here:

24.04 with Kernel 5.15

Please describe your issue below:

I would like to insert external sdio device into micro SD solt.
But it uses 1.8V as communication (signal voltage) not 3.3V.

I tried to modify kernel DTS as the following sd_emmc_b table to adjust signal voltage from 3.3V to 1.8V in
linux/common_drivers/arch/arm64/boot/dts/amlogic/kvim3.dts.
After built & copyed kvim3.dtd into VIM3, mmc1 still kept 3.3V as signal voltage.
I’m not sure why vmmc-supply & vqmmc-supply is hidden in common driver DTS. (Not work?)

Could anyone let me know how to adjust signal voltage correctly in common driver DTS?
Thanks!!

&sd_emmc_b {
//vmmc-supply = <&vddao3v3_reg>;
//vqmmc-supply = <&vddio_c>;
vmmc-supply = <&vddao3v3_reg>;
vqmmc-supply = <&vddio_ao18_reg>;
sd-uhs-sdr12;
sd-uhs-sdr25;
sd-uhs-sdr50;
sd-uhs-sdr104;

status = “okay”;
pinctrl-0 = <&sdcard_pins>;
pinctrl-1 = <&sdcard_clk_gate_pins>;
pinctrl-2 = <&sd_1bit_pins>;

…

Post a console log of your issue below:

When insert this device into micro SD solt, I guess wrong signal voltage causes communication timeout.

[   38.302238][0 T0     dh] meson-gx-mmc ffe05000.sd: 8 [0x1aa], TIMEOUT[0x2800]
[   38.304853][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   38.311776][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   38.318691][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   38.325598][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   38.332533][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   38.339558][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   38.346579][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   38.353611][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   38.360668][0 T0     dh] meson-gx-mmc ffe05000.sd: 1 [0x0], TIMEOUT[0x2800]
[   39.422079][0 T0     dh] meson-gx-mmc ffe05000.sd: 8 [0x1aa], TIMEOUT[0x2800]
[   39.424629][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   39.431553][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   39.438491][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   39.445418][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   39.452348][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   39.459377][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   39.466424][0 T20    dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   39.473465][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   39.480502][0 T0     dh] meson-gx-mmc ffe05000.sd: 1 [0x0], TIMEOUT[0x2800]
[   40.541811][0 T0     dh] meson-gx-mmc ffe05000.sd: 8 [0x1aa], TIMEOUT[0x2800]
[   40.544384][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   40.551295][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   40.558225][0 T20    dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   40.565193][0 T0     dh] meson-gx-mmc ffe05000.sd: 5 [0x0], TIMEOUT[0x2800]
[   40.572093][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   40.579128][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   40.586138][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   40.593156][0 T0     dh] meson-gx-mmc ffe05000.sd: 55 [0x0], TIMEOUT[0x2800]
[   40.600218][0 T0     dh] meson-gx-mmc ffe05000.sd: 1 [0x0], TIMEOUT[0x2800]

numbqq · April 24, 2025, 10:16am

Hi @Mater ,

For VIM3, you can only change the voltage of VDDIO_C

echo 409 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio409/direction
echo 0 > /sys/class/gpio/gpio409/value    # setup to 3.3V
echo 1 > /sys/class/gpio/gpio409/value    # setup to 1.8V

The GPIO to control VDDIO_C is GPIO7 in GPIO expander, so you need to setup correct gpio in your vddio_ao18_reg node.

github.com/khadas/common_drivers

arch/arm64/boot/dts/amlogic/kvim3.dts

khadas-vims-5.15.y


      
          				FF FF FF FF FF FF FF FF 6F 01];
              };
          };
          
          &i2c_AO {
          	status = "okay";
          	pinctrl-names="default";
          	pinctrl-0=<&ao_i2c_master_pins1>;
          	clock-frequency = <100000>; /* default 100k */
          
          	gpio_expander: gpio-controller@20 {
          		compatible = "ti,tca6408";
          		reg = <0x20>;
          		gpio-controller;
          		#gpio-cells = <2>;
          		status = "okay";
          	};
          
          	hym8563-rtc@51 {
          		compatible = "haoyu,hym8563";
          		reg = <0x51>;

Regards,
Nick

Mater · April 25, 2025, 1:00am

Dear numbqq,

Thank you for your information.
I’m checking this.

Best regards,
Mater

Mater · April 25, 2025, 2:02am

Dear Nick,

After set value of gpio409, it can switch signal voltage of SD data as 1.8V.

Execus me. I just touch VIM3 board less than one monuth.
Could I ask more about gpio409?

Refer how-to-get-gpio-numbers… as the follow.
I still didn’t get the meaning of gpio409.
Which document or formal website can I study whose definition is gpio409?
Thank you!!

$cat /sys/kernel/debug/pinctrl/pinctrl-devices
name [pinmux] [pinconf]
pinctrl-meson yes yes
pinctrl-meson yes yes
pinctrl-audio-g12a yes no

$ cat /sys/kernel/debug/pinctrl/pinctrl@ff634480-pinctrl-meson/gpio-ranges
GPIO ranges handled:
0: periphs-banks GPIOS [410 - 494] PINS [0 - 84]

$ cat /sys/kernel/debug/pinctrl/pinctrl@ff800014-pinctrl-meson/gpio-ranges
GPIO ranges handled:
0: aobus-banks GPIOS [496 - 511] PINS [0 - 15]

$ cat /sys/kernel/debug/pinctrl/ff642000.audiobus\:pinctrl-pinctrl-audio-g12a/gpio-ranges
GPIO ranges handled:

numbqq · April 25, 2025, 2:44am

Hi @Mater,

gpiochip402 is the GPIO expander, you can get the GPIO expander GPIOs from:

# cat /sys/class/gpio/gpiochip402/ngpio
8

Base number:

# cat /sys/class/gpio/gpiochip402/base 
402

So the GPIO number is: 402~409

Regards,
Nick

Mater · April 25, 2025, 4:50am

Hi @numbqq

Thanks for your information.
I got the point.

GPIO 409 is SD_MODE pin from TCA6408 device (start from gpio 402) to adjust VDDIO_C output as 3.3V or 1.8V.
Sorry, I was just little confused about why I did’t find GPIO definition of VDDIO_C or SD_MODE in DTS table. Now, I understand it.

Best regards,
Mater