Configure IOMUX mapping address in devicetree

Technical Support
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1

Hello,
I have used toradex apalis imx8 processor for customize board.
Please let me know how to configure iomux pin address available device-tree like
/* Apalis I2C3 (CAM) */
pinctrl_lpi2c3: lpi2c3grp {
fsl,pins = <
IMX8QM_SIM0_PD_DMA_I2C3_SCL 0x04000020
IMX8QM_SIM0_POWER_EN_DMA_I2C3_SDA 0x04000020
>;
};

Where I can get the this address information ?
I also look in reference manual of imx8q processor of pad/mux control function fields but I have some confusion to extract this address with function detail.
Please send me the detail information of each bit of below pin function address.
IMX8QM_SIM0_PD_DMA_I2C3_SCL 0x04000020

2

Hello @dipakshetye,

Would you mind sharing what kernel you are using? The device output of uname -r -s -m will be helpful.
Also, are you wanting to using torizoncore builder to modify the module image?

I will link a few articles I think will greatly help.

Here is an article on pin multiplexing. I think it will provide good fundamental information.

Here is one on device trees.

-Eric

The 0x0XXXXX value is a reference value/‘magic value’ that is set via the NXP reference manual per SoC. There isn’t a clear way to state what each specific value does without looking it up. In general the value configures the pin such that it has different functionality.S uch as pull up/pull down, slew rates, ect.

3

Hello,
Thank you for your reply.
root@apalis-imx8-06980499:~# uname -r -s -m
Linux 5.4.193-5.7.1-devel+git.f78299297185 aarch64
root@apalis-imx8-06980499:~#

We are using yocto build to modify the module image.

Please let me know the detail information of each bit in the address like
IMX8QM_SIM0_PD_DMA_I2C3_SCL 0x04000020

4

For details on modifying the hex value you’ll need to reference the NXP reference manual here: (you will need to make an account with NXP to view this document).

i.MX 8QuadMax Applications Processor Reference Manual
https://www.nxp.com/webapp/Download?colCode=IMX8QMRM

If you go to section: 9.2.5.1.5 SIM0_PD you will find details on the configuration and what each value means. You can see this via the fields value to function chart (9.2.5.1.5.4), and the corresponding bit values locations via the diagram (9.2.5.1.5.3). Just keep in mind these are binary values that get converted to hex values when viewed in the device tree.

We see a similar case for SIM0_POWER_EN at section 9.2.5.1.6.2

-Eric

5

Hello @dipakshetye,

Did you get all the information you needed?

-Eric