TGPIO output on full-function eval carrier board

[ben-at-calnex]

Hello,

I'm trying to get TGPIO output from the LattePanda Mu.
If I understand properly:

• This should be available on pin 123 of the Mu board when using BIOS LP-BS-S70NC1R200-SR-TGPIO.
• The schematics of the carrier indicate that this should be routed to the GPIO_1 header, pin 7.

The BIOS update seems to have happened fine (I saw it reboot a few times after the update).
But I don't get anything on that pin of GPIO_1.

Do you know what could be wrong?
The readme next to the BIOS zip mentions that the "1pps pulse signal is continuously output", but maybe a BIOS setting needs to be changed to enable this feature, or a specific driver is needed to enable the output?

Thanks,
Ben

[sfcal]

I am also running into this same issue. @ben-at-calnex did you find a solution to this?

[ben-at-calnex]

Hi @sfcal - I've found out that on top of the special BIOS, TGPIO output requires a specific kernel driver.
It seems it has started appearing in the mainline kernel: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pps/generators/Kconfig?h=v6.15#n34
This new driver does not probe any device automatically for me on a LattePanda Mu, though (I've tried with kernel 6.17 on Ubuntu 24.04).

[sfcal]

@ben-at-calnex This is great info. I see Ahmad Byagowi's static detect patch too. Really appreciate the lead.