I’m trying to enable uartg/uart7 on Jetson AGX Xavier devkit with R32 (release), REVISION: 5.1 to manually connect a serial device to the respective PCI-E pins.
Therefore I have changed pinmux of SPI2 pins via Excel tool, which resulted in a modified bootloader/t186ref/BCT/tegra19x-mb1-pinmux-p2888-0000-a04-p2822-0000-b01.cfg. Then, flashing with ./flash.sh -k MB1_BCT jetson-agx-xavier-devkit mmcblk0p1 makes the readout of /sys/kernel/debug/tegra_pinctrl_reg change, so I expect it to be successful.
Still, I don’t get a serial device on 0x0c290000 and believe , I need to enable the driver for it. I tried doing that by modifying a otherwise working custom.dtb generated with jetson-io. I tried setting the serial@0c290000 section status to okay, which resulted in bootloop and the following error:
[ 0.831755] gpiochip_add_data: GPIOs 288..511 (tegra-gpio) failed to register [ 0.831795] gpio-tegra186 2200000.gpio: Could not register gpiochip, -517 [ 0.832608] gpiochip_add_data: GPIOs 472..511 (tegra-gpio-aon) failed to register [ 0.832647] gpio-tegra186 c2f0000.gpio: Could not register gpiochip, -517
The full log is attached: custom-boot.log (51.7 KB)
I wonder what I’m doing wrong and whether I need to recompile the kernel. On the other hand, device trees were invented to not need to recompile kernel for reconfiguration, right?
The only related topic I found for not older JetPack versions is How to disable SPI2 and enable UART7. That does unfortunately leave open my issue.
How to enable UART7 (D8, D5) as normal UART like other UART (uartc@C280000) - #50 by williamho is very close, but I cannot get more out of it than I did describe above. The BPMP section doesn’t seem to apply for my case - different hardware.
Thanks for your help!