Configuring GPIO Pullup Resistor for Jetson Orin Nano Dev Board

Issue Overview

Users are experiencing difficulties in enabling a pullup resistor for a specific GPIO pin (pin 228) on the Nvidia Jetson Orin Nano Dev board. This issue arises in the context of attempting to enable a second USB-C port on a custom carrier board. The problem appears to be related to pinmux configuration and the application of changes to the device tree.

Possible Causes

1. Incorrect Pinmux Configuration: The user may not have properly configured the pinmux settings for the desired GPIO pin.

2. Unapplied Changes: The pinmux changes may have been made but not correctly applied to the system.

3. Incomplete Device Tree Modification: The device tree files might not have been properly generated or placed in the correct locations.

4. Outdated Board Configuration: The board configuration file may not have been updated to include the custom pinmux settings.

5. Flashing Issues: The changes may not have been applied due to an incomplete or incorrect flashing process.

Troubleshooting Steps, Solutions & Fixes

To resolve the issue of configuring the GPIO pullup resistor, follow these steps:

1. Generate Device Tree Files

   • Create new device tree files named new-pinmux.dtsi and gpio.dtsi.
   • Ensure that the correct gpio.dtsi is included in your pinmux file.

2. Place Device Tree Files in Correct Path

   • Copy new-pinmux.dtsi, gpio.dtsi, and padvoltage files to:

     $OUT/Linux_for_Tegra/bootloader/generic/BCT/
     

3. Modify Board Configuration

   • Edit the board configuration file (e.g., p3701.conf.common).
   • Replace the existing PINMUX_CONFIG line with:

     PINMUX_CONFIG="new-pinmux.dtsi";
     

4. Apply Changes

   • Perform a full flash of your target device to apply the changes.

5. Follow Official Documentation

   • Refer to the NVIDIA Jetson documentation for detailed instructions on MB1 configuration changes:
     https://docs.nvidia.com/jetson/archives/r35.2.1/DeveloperGuide/text/HR/JetsonModuleAdaptationAndBringUp/JetsonOrinNxSeries.html#mb1-configuration-changes

6. Verify Pinmux Changes

   • After applying changes, check if the pin state has changed as expected.
   • If issues persist, double-check your pinmux configuration and ensure all steps were followed correctly.

7. Consult Additional Resources

   • If problems continue, consider consulting NVIDIA’s developer forums or support channels for more specific assistance.

Remember to backup your current configuration before making any changes. If you encounter any errors during the process, carefully review each step and ensure all file paths and configurations are correct for your specific Jetson Orin Nano Dev board setup.