IMX8MP I2C Linux Device tree pinctrl question

[flobro]

I have a I2C pinctrl setting in the device tree that I am trying to understand...

pinctrl_i2c4: i2c4grp {
fsl,pins = <
MX8MP_IOMUXC_I2C4_SCL__I2C4_SCL 0x400001c2
MX8MP_IOMUXC_I2C4_SDA__I2C4_SDA 0x400001c2
>;
};

What is the 0x4000 part in the 0x40001c2 pad setting? The SW_PAD_CTL register only supports 9 bits, so the 0x01c2 part makes sense...

I can't find where the extra 0x4000 is applied.

Thanks

[flobro]

"SION"  was the keyword that finally led to documentation. Im the IMX8MP App Ref Manual "8.2.2.3 SW Loopback through SION bit" and 

"17.1.3 External Signals" -- "Inputs of I2Cn_SCL and I2Cn_SDA also need to be manually enabled by setting the
SION bit in the IOMUX after the corresponding PADs are selected as I2C function."

(I am not familiar with "config tools", guess I am old school. But I will look it up.)

Thanks for the clue.

[Alejandro_Salas · Accepted solution]

Hello @flobro 

If you are using Config tools to configure de IOMUX, you will see the 0x4000 belong to "Software Input On Field.

If enabled:

If disabled:

I hope this can helps to you.

Best regards.

Salas.