I/O Expander - TCA9539 - configuring with device tree

Hi,
I’m trying to set the defaults for the GPIO pins controlled by the TCA9539 GPIO expander on the Jetson.

Where should the device tree be modified?
How to manipulate these I/O’s from a running system?

The standard “echo > export” method fails with “device or resource busy”, probably because the expander driver controls these pins.

Thanks.

hello Mike_0b,

the device Jetson TX2 used is tegra186-quill-p3310-1000-c03-00-base.dtb,
it is composite with several module device trees.
you’re able to find them under below path. thanks

r28.1_sources/hardware/nvidia/platform/t18x/

Hi JerryChang,

Thanks,
I am aware of the location of the DTS file, I was asking more about the exact property value for these pins, but I think I got it already:

In

tegra186-cvb-prod-p2597-b00-p3310-1000-a00-00.dtsi

, I modified the

gpio@74

property (for the expander at I2C address 0x74).

However, I’m still not sure how to toggle the pins from a running system.

hello Mike_0b,

could you please refer to below similar topic,
thanks

https://devtalk.nvidia.com/default/topic/1001584/jetson-tx2/gpio-pinmux/post/5226482/#5226482