Xavier NX changing pin function

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
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1

Hello,
I’m a littile bit confused about how should I modify a pin configuration.
I’m using Xavier NX development kit, and I want to use 2 SPI interfaces by changing the pin configuration from GPIO to SPI.
What have I done so far is:

  1. Edited the xlsm file.
  2. Generated 3 dtsi files from the xlsm file.
  3. Created 2 cfg files (one for PINMUX and GPIO and another for PAD VOLTAGES) according to the readme file in Linux_for_Tegra/kernel/pinmux/t19x

I saw this guide https://docs.nvidia.com/jetson/l4t/#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/mb1_platform_config_xavier.html#wwpID0E0H50HA
But it’s not so clear how to continue.

I have a few questions regarding the next steps:

  1. What should I do with the cfg files? Should they have a specific name?
  2. What should I do with the 3 dtsi files I’ve generated from the xlsm file?
  3. How should I generate the new dtb file? I’m familiar with the dtc tool to compile the device tree files but should I somehow include the generated dtsi files into the directory of the dts sources located in directory Linux_for_Tegra/sources/hardware/nvidia/platform/t19x/jakku/kernel-dts
    and after that run the dtc?
  4. How should I flash cfg files?
    a. Will the following command flash the cfg files to the board?
    sudo ./flash.sh -r -k bpmp-fw-dtb jetson-xavier-nx-devkit mmcblk0p1
    b. If I run from nvme should it be as following?
    sudo ./flash.sh -r -k bpmp-fw-dtb jetson-xavier-nx-devkit nvme0n1
    I would like to keep the rootfs contant and not to do full flash.
  5. Should I change anything in the device tree sources in order to change pin function?

Please help me to understand this issue

Thanks,

3

hello boris16,

you should copy those dtsi file to your local x86 host machine and re-compile the device tree blob (i.e. *.dtb)
the generated *.cfg file used by the flashing process, you need to perform the full flash to apply the changes correctly.

4

Hi JerryChang,

Thanks for the reply.
I still have few questions:

Which names should I give to cfg and dtsi files?

Should I copy the dtsi files to Linux_for_Tegra/sources/hardware/nvidia/platform/t19x/jakku/kernel-dts/common directory? And how to be sure that those files are compiled, should I edit one of the dts files and include my dtsi files there?

Thanks for your help
Boris

5

hello boris16,

please check the flash messages for the actual binary and configure files that burning to the target.
for example,

[   4.0498 ] Parsing config file :tegra19x-mb1-pinmux-p3668-a01.cfg

[ 464.1538 ] Writing partition kernel-dtb with tegra194-p3668-all-p3509-0000_sigheader.dtb.encrypt
[ 464.1617 ] [................................................] 100%
1 Like
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Hi Jerry,
I still didn’t understand the whole workflow of changing the pinmux.
I saw the Pinmux Changes section in Nvidia guid:
https://docs.nvidia.com/jetson/l4t/#page/Tegra%20Linux%20Driver%20Package%20Development%20Guide/adaptation_and_bringup_xavier_nx.html#wwpID0E0VL0HA

But it is not clear what to do with the generated dtsi and cfg files.

dtsi sources are located in directory
Linux_for_Tegra/sources/hardware/nvidia/platform/t19x/jakku/kernel-dts/common
How should I include the generated dtsi files?

Should I copy the cfg files into the following directory?
Linux_for_Tegra/bootloader/t186ref/BCT
Should the generated cfg files have a specific name or they should replace some of the existing files?

Thanks,
Boris

7

please check this thread, Custom carrier board with NX module for reference, thanks

8

Thanks, I still don’t understand how to integrate the generated dtsi file into the device tree sources

2 Likes
9

hello boris16,

please access https://developer.nvidia.com/embedded/linux-tegra and download the BSP sources package.
you should also refer to developer guide for Building the NVIDIA Kernel.
thanks

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