E25 gpio serial console

#1

I’m trying to add support for the E25 board in openwrt but currently I’m facing some issues with the network driver (r8169) and I’m unable to debug further as I can’t get any serial access to the board.
Any idea how to enable serial access via GPIO ?
thanks

#2

Hmm, regarding to this:

https://wiki.radxa.com/Rock3/CM/CM3I/E25/getting_started

You have to use the usbc port for serial console, not gpio, and it is set to 115200.

#3

thank you for the reply - unfortunately it only work during u-boot stage - then it disconnects - see logs:

[  607.283625] usb 1-2: new full-speed USB device number 6 using xhci_hcd
[  607.433925] usb 1-2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.54
[  607.433947] usb 1-2: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[  607.433955] usb 1-2: Product: USB2.0-Serial
[  607.521146] usbcore: registered new interface driver usbserial_generic
[  607.522655] usbserial: USB Serial support registered for generic
[  607.528260] usbcore: registered new interface driver ch341
[  607.530642] usbserial: USB Serial support registered for ch341-uart
[  607.530928] ch341 1-2:1.0: ch341-uart converter detected
[  607.539675] usb 1-2: ch341-uart converter now attached to ttyUSB0
[  607.601090] input: PC Speaker as /devices/platform/pcspkr/input/input18
[  608.179473] input: BRLTTY 6.4 Linux Screen Driver Keyboard as /devices/virtual/input/input19
[  608.185521] usb 1-2: usbfs: interface 0 claimed by ch341 while 'brltty' sets config #1
[  608.189347] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[  608.189381] ch341 1-2:1.0: device disconnected

I will search the u-boot code maybe I can find something relevant there

#4

This is probably not because of the U-Boot, but when the kernel is loaded. Hence, what kernel is it? From OpenWRT? This image?

https://dl.radxa.com/cm3i/e25/openwrt/openwrt_rk3568_e25_R23.07.07_k6.1.38-flippy-84+.7z

And what is the “initial” log text transmitted?

#5

which distro are you using as HOST machine?
could you try to remove “brltty” package from HOST?

#6

I’m trying to add official support in mainline openwrt - currently with kernel 6.1 but I can build any 6.x even mainline see Openwrt official support request

that did it !!!
now I have serial console via usb-C port on my ubuntu 22.04 - thank you very much !