Need to use GPIO3_PA.02, but it is locked, why?

Okay, please configure it in pinmux spreadsheet as following first.
image

For Jetpack6.2(r36.4.3), you may need to apply the patch from 40hdr - SPI1 gpio padctl register bit[10] effect by gpiod tools in JP6 - #20 by KevinFFF.

After you reflash the board to apply the change, please simply run the following command to check if you can control this pin as expected.

# gpioset --mode=wait `gpiofind "PA.02"`=1
# gpioset --mode=wait `gpiofind "PA.02"`=0