Making a GPIO low in device tree of Xavier NX, Jetpack 4.5.1

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

Hi, i want to make the GPIO pin low in my jetson Xavier NX, I have flashed JP4.5.1.
I don’t know if this is the file which i need to write the changes for GPIO, tegra-194-p3668-all-p3509-0000.dts. if this is the right one how should i write the changes in the file?

3

Hi manojk1,

Are you using the devkit or custom board?

Do you want you want to control the pin in runtime or configure the default pin state?
Have you tried to use the pinmux spreadsheet?

4

Am using devkit, i want to set the default state. Yes am using the pinmux.

5

Your topic is in Jetson Nano category.

Are you using Jetson Nano or Xavier NX?

Is there any issue when you configure pin state through pinmux spreadsheet?

6

So, am making use of some scripts which does the building the device tree and flashing it. Am using Xavier-NX EMMC. And i want to configure pin as default.

7

I’ve moved your topic to correct category for Xavier NX.

Do you refer to the following instruction for pinmux change?
NVIDIA Jetson Linux Developer Guide : Jetson Module Adaptation and Bring-Up - Pinmux Changes
The generated file should be XXX.cfg and please put it into <Linux_for_Tegra>/bootloader/t186ref/BCT/

8

What if i just want to add the GPIO state into the dts. Can you confirm which file it would be? if its the same one that i mentioned, then i just need to define the pin like this and it will be done?
"define GPIO9 TEGRA_GPIO(S, 4)

micro-controller-output {
status = ““okay””;
gpio-hog;
output-low;
gpios = <GPIO9 0>;
label = "“gpio1"”;
};
"

9

Yes, you could also use the lines you shared to configure GPIO state.
You would need to build kernel image and dtb for this use case.

TEGRA_GPIO(S, 4) should be TEGRA194_MAIN_GPIO(S, 4) for Xavier NX.

10

So just want to confirm that i can make changes like this?? this is the change i made in tegra-194-p3668-all-p3509-0000.dts

/dts-v1/;
include “common/tegra194-p3668-common.dtsi”
include “common/tegra194-p3509-0000-a00.dtsi”
define GPIO9 TEGRA194_MAIN_GPIO(S, 4)
/ {
nvidia,dtsfilename = FILE;
nvidia,dtbbuildtime = DATE, TIME;

compatible = "nvidia,p3449-0000+p3668-0000", "nvidia,p3449-0000+p3668-0001", "nvidia,p3509-0000+p3668-0000", "nvidia,p3509-0000+p3668-0001", "nvidia,tegra194";

};
micro-controller-output {
status = ““okay””;
gpio-hog;
output-low;
gpios = <GPIO9 0>;
label = ““gpio1””;
};

11

Yes, please apply it and build the kernel image and dtb.

12

Thank you it worked.

14

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