Pin multiplexing

Technical Support
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1

Hi.

I’m working on pin multiplexing for a few days. I customized IOMUX in .dts file and then i compiled it for creation .dtb file. What should i do next for creating a new image with my new pins?

2

Hello @ogusis01 ,
Do you want to create a new Yocto image or a new TorizonCore image?

Best regards,
Josep

3

I’m trying to create new Yocto image.

4

Either, is it possible to change the pin functionalities of an already existing image(e.g. tdx-reference-multimedi-image, tdx-minimal-image) in yocto by changing only the dts file it uses?

5

Hi @ogusis01 ,

Which carrier board are you using?

I assume you were following this article here right?

There’s also an article leading through the whole process of building one of our reference images.

Does this help?

Best Regards
Kevin

6

Hi again. I’m using BSP 5.0 reference image on my colibri imx6. I’m trying to configure my pins with device tree overlay. The steps I followed are listed below.

  1. Write a .dts file.
    2)Compile it to .dtbo.
    3)Copy this .dtbo file to “/boot/overlays” directory in Colibri imx6
    4)Write "fdt_file=dtboname.dtbo
    5)sync and reboot
    As a result, I get the following error during boot
In:    serial
Out:   serial
Err:   serial
Model: Toradex Colibri iMX6 DualLite 512MB IT V1.1Z, Serial# 10885648
Net:   eth0: ethernet@2188000
Hit any key to stop autoboot:  0 
MMC: no card present
switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0:1...
Found U-Boot script /boot.scr
5752 bytes read in 13 ms (431.6 KiB/s)
## Executing script at 17000000
Loading DeviceTree: imx6dl-colibri-eval-v3.dtb
63342 bytes read in 19 ms (3.2 MiB/s)
47 bytes read in 10 ms (3.9 KiB/s)
Applying Overlay: imx6dl-colibri-my-carrier-v3.dtbo
914 bytes read in 25 ms (35.2 KiB/s)
failed on fdt_overlay_apply(): FDT_ERR_NOTFOUND
8516096 bytes read in 302 ms (26.9 MiB/s)
Bootargs: enable_wait_mode=off galcore.contiguousSize=50331648 root=PARTUUID=f5b9b830-02 ro rootwait fec_mac=00:14:2d:a6:1a:10 consoleblank=0 no_console_suspend=1 console=tty1 console=ttymxc0,115200n8 fbmem=8M
ERROR: Did not find a cmdline Flattened Device Tree

Starting kernel ...

Dts file that i wrote is in below

/dts-v1/;
/plugin/; 

#include <imx6dl-pinfunc.h>

/ {
    compatible = "toradex,colibri-imx6dl";
};

&iomuxc {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_my_pins>;  
        pinctrl_my_pins: my_muxgrp {
            fsl,pins = <
			MX6QDL_PAD_SD4_DAT4__GPIO2_IO12 0x1b0b0
			MX6QDL_PAD_SD4_DAT7__GPIO2_IO15 0x1b0b0
				
		 >;
        };
    };
&genericPeripheral {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_my_pins>; 
    status = "okay";
};

&uart2 {
	status = "disabled";
};

Can you help me find where I went wrong?

7

Hi @ogusis01!

Yes. It is possible. Please check the Custom meta layers, recipes and images in Yocto Project (hello-world examples) | Toradex Developer Center article for the device tree example.

This kind of structure on a device tree file is meant to customize an already existing node that must be defined somewhere else. As we do not have a node labeled genericPeripheral anywhere on our set of device tree files for Colibri iMX6DL, your overlay will fail to be applied.

I would recommend you study more about device trees to understand how they work (which can be quite tough to understand).

The following references will help you with this task:

(above link was already shared by @kevin.tx)

An a nice Application Note from NXP about Device Tree files:

Best regards,

8

Hi @henrique.tx
Thanks for your answer.

Can I add pin to pinctrl defined under dtsi file with device tree overlay?

9

Hi @ogusis01 !

Yes, you can.

But it works like a complete “do-over”. You need to copy the pinctrl content, paste it into your device tree overlay and then add/remove/modify the pins you want.

Best regards,

10

Hi @ogusis01 !

Do you have any updates on this issue?

Were you able to sort this out?

Best regards,