Kernel PPS processing
dan-ntp at drown.org
Tue Jul 5 00:27:50 UTC 2016
Quoting "Gary E. Miller" <gem at rellim.com>:
> Good stuff, but I find no mention of GPIO timestamping..
pps-gpio takes the timestamp in the kernel interrupt handler.
The code is here:
To do this, the GPIO peripheral in the BCM2835 is configured to
interrupt on an edge, with this code:
GPREN0 / GPFEN0 are defined in
as "GPIO Falling Edge Detect Enable Registers (GPRENn)"
and "GPIO Rising Edge Detect Enable Registers (GPRENn)"
You can also see the interrupt in the proc filesystem:
$ grep pps /proc/interrupts
170: 900414 0 0 0 pinctrl-bcm2835 4
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