Wiki documentation device tree / pinmux

[jlucke86]

I've been trying for a few hours to setup the pinmux without success. I taught myself how to get the register values from the nvidia pinmux spreadsheet tool by generating the .dtsi files and then convert the output to cfg and then manually diff the files so I can see the cpu registers that require changing and then use use devmem2 to set the settings on a live system.

Could I please have some guidance what is the accepted way to slice in the .dtsi files or .cfg into my system images.

[kekiefer]

You can do this by adding a bbappend to tegra-flashvars that deploys the customized pinmux .cfg files (you don't need the dtsi files except to generate those cfgs). You also need to provide a copy of the flashvars file that refers to your cfg files. You'll end up with something like this:

meta-mylayer/recipes-bsp/tegra-binaries/tegra-flashvars_%.bbappend
meta-mylayer/recipes-bsp/tegra-binaries/tegra-flashvars/mymachine/
meta-mylayer/recipes-bsp/tegra-binaries/tegra-flashvars/mymachine/flashvars
meta-mylayer/recipes-bsp/tegra-binaries/tegra-flashvars/mymachine/tegra19x-mb1-pinmux-mymachine.cfg
meta-mylayer/recipes-bsp/tegra-binaries/tegra-flashvars/mymachine/tegra19x-mb1-padvoltage-mymachine.cfg

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}:"

SRC_URI_append_mymachine = " file://tegra19x-mb1-pinmux-mymachine.cfg \
    file://tegra19x-mb1-padvoltage-mymachine.cfg \
"

do_install_append_mymachine() {
    install -d ${D}${datadir}/tegraflash
    install -m 0644 ${S}/*.cfg ${D}${datadir}/tegraflash/
}

[jlucke86]

Thanks, that information is really helpful.

I'm reading the existing recipes-bsp/tegra-binaries/tegra-flashvars/xavier-nx/flashvars file and its referring to file

PINMUX_CONFIG="tegra19x-mb1-pinmux-p3668-a01.cfg"

Where do I find this pre existing tegra19x-mb1-pinmux-p3668-a01.cfg file? It doesn't seem to be in tegra-linux_4.9 or meta-tegra repos? I usually like to read the existing code / settings before changing anything

Contents of tegra-flashvars/xavier-nx/flashvars

FLASHVARS="BPFDTB_FILE PMIC_CONFIG SCR_COLD_BOOT_CONFIG MISC_COLD_BOOT_CONFIG PINMUX_CONFIG PMC_CONFIG UPHY_CONFIG DEVICE_CONFIG GPIOINT_CONFIG PROD_CONFIG SCR_CONFIG BR_CMD_CONFIG DEV_PARAMS"
BPFDTB_FILE="tegra194-a02-bpmp-p3668-a00.dtb"
PMIC_CONFIG="tegra194-mb1-bct-pmic-p3668-0001-a00.cfg"
SCR_COLD_BOOT_CONFIG="tegra194-mb1-bct-scr-cbb-mini-p3668.cfg"
MISC_COLD_BOOT_CONFIG="tegra194-mb1-bct-misc-l4t.cfg"
PINMUX_CONFIG="tegra19x-mb1-pinmux-p3668-a01.cfg"
PMC_CONFIG="tegra19x-mb1-padvoltage-p3668-a01.cfg"
UPHY_CONFIG=""
DEVICE_CONFIG="tegra19x-mb1-bct-device-qspi-p3668.cfg"
GPIOINT_CONFIG="tegra194-mb1-bct-gpioint-p3668-0001-a00.cfg"
PROD_CONFIG="tegra19x-mb1-prod-p3668-0001-a00.cfg"
SCR_CONFIG="tegra194-mb1-bct-scr-cbb-mini-p3668.cfg"
BR_CMD_CONFIG="tegra194-mb1-bct-reset-p3668-0001-a00.cfg"
DEV_PARAMS="tegra194-br-bct-qspi.cfg"

[kekiefer]

This comes from the tegra-binaries package which is unpacked into: ${TMPDIR}/work-shared/L4T-${L4T_BSP_ARCH}-${PV}-${PR}/Linux_for_Tegra. So, for master you'd find that here: ${BUILDDIR}/tmp/work-shared/L4T-tegra-32.4.3-r0/Linux_for_Tegra/bootloader/t186ref/BCT/tegra19x-mb1-pinmux-p3668-a01.cfg

[jlucke86]

OK that is super helpful. I'll give it another go now.

[jlucke86]

At this stage it looks like you've helped me to get the cfg files into my file system. I'm not sure the cfg files are correct now

Is there a special version of the pinmux 2 cfg python script suited for the xavier-nx, or I can use any of them located under the t19x / t194 folder?

[madisongh]

It should be the one at Linux_for_Tegra/kernel/pinmux/t19x. See the README.txt file there for instructions. The copy in t186 is for the TX2 only.

I've only used the TX2 cfg generator myself, but I did end up manually adjusting the resulting cfg files, since the script doesn't always generate 100% correct results. You may have to do the same with the t19x output... generating diffs from the stock cfg files and consulting the documentation on the pins to make sure the differences really reflect what you entered into the spreadsheet.

[atharvanan1]

Thanks @madisongh and @kekiefer for this! It felt really finicky to change the pinmux. I was also afraid to do this as I might get something wrong and things would not work or send 3.3V to 1.8V domain. Here's the workflow I followed for changing assignment of only one pin:

1. Use the Jetson Pinmux excel spreadsheet to generate dtsi files.
2. Use these files and the instructions from Linux_for_Tegra/kernel/pinmux/t19x or Linux_for_Tegra/kernel/pinmux/t186 README.txt files. Here we use a python script to generate *.cfg file.
3. Use these generated files and diff them with the stock files found at ${BUILDDIR}/tmp/work-shared/L4T-tegra-32.4.3-r0/Linux_for_Tegra/bootloader/t186ref/BCT/tegra19x-mb1-pinmux-p3668-a01.cfg, copy the original cfg file and add these diffs manually which only concern the pin we want to change.
4. Use new file (with stock-cfg + diffed pin contents) and follow @kekiefer's instructions from here - Wiki documentation device tree / pinmux #735 (comment)

[dwalkes]

Cross-linking gitter thread on this topic at https://gitter.im/OE4T/community?at=639608273daaa326ba7d2c7c and an existing wiki page at https://github.com/OE4T/meta-tegra/wiki/Controlling-Jetson-TX2-pin-states