rpi5 configuration for GPIO UART

[joaohf]

Hi,

For rpi5, I want to use GPIO (pints 14/15) UART. Does anyone know the correct configuration to be use with meta-raspberrypi ?

I've built a core-image-base that is working but as I don't have the pi debug UART cable/device, I would like to try the GPIO instead.

Thanks.

[jackxl]

Have you tried 'enable_uart=1' ?

This stuff is configured using the config.txt and works the same as with raspbian. I'd recommend checking the documentation for the rpi5. https://www.raspberrypi.com/documentation/computers/config_txt.html#enable_uart

[joaohf]

Hi,

I'm using the following configuration:

DISABLE_SPLASH = "1"

VIDEO_CAMERA = "0"

DISABLE_RPI_BOOT_LOGO = "1"

ENABLE_SPI_BUS = "1"

ENABLE_I2C = "1"

# Enable serial console on Raspberry PI systems
ENABLE_UART = "1"

I suppose 'ENABLE_UART' will make the right configuration at config.txt.

I'll also double check if my usb device is working fine.

[joaohf]

Here is cmdline.txt and config.txt generated by meta-raspberrypi:

cmdline.txt

config.txt

enable_uart is 1.

[gizahNL]

If you want boot console output this isn't on pin14/15, it's on a separate header. It's possible with some tricks to get earlycon on pin 14/15, but you won't get U-Boot output (pin14/15 lives on the RP1 chip GPIO, which is connected via PCI-E, PCI-E support for Pi5 isn't in the U-Boot tree as of yet)

[gizahNL]

See my comments here: https://github.com/agherzan/meta-raspberrypi/issues/1394 for some syntax regarding UART and earlycon (yours might differ since the CM5 ends up with slightly different addresses iirc).