and verified pps client is working using pps-tools.
I’d like to use TX1 GPIO pin 13 of J21 (pe6 in dtb?) as 1PPS input.
What need to be done to have pps client triggered by GPIO instead of ktimer?
Pin 13 is OK to be used as PPS input. But about “verified pps client is working using pps-tools”, I am curious how you verify it? What is this “pps client” ?
Any ideas on how to use GPIO or UART CTS pin as PPS input for line discipline?
PPS line discipline is very important for UAV or NTP applications and has been implemented for Raspberry Pi and other arm processors.
PPS line discipline is already built in Linux kernel, the missing link is from TX1 GPIO or CTS to the kernel.
Hi yahoo2016,
Sorry for not able to respond earlier as this is not a straightforward answer. Bottom line is the hardware support for PPS signal is only available in the chip after Jetson TX1. To achieve similar result, one can use the approach to input the same signal, say GPS PPS, to both devices to synchronize the clock. This is interrupt based and there is latency issue to resolve. For that, we suggest using TSC (TRM section 8.2) due to its nature of oscillator granularity. There is a ktime_get_ts() kernel call, however it depends on your latency needs.