The problem is still present. I'm using the 21.02 branch and made some tests.
Using the GPIO 16 with IRQ on Falling Edge:
interrupts = <16 0x02>
the IRQ appears on the right position but on wrong GPIO bank:
GPIO
0-31 32-63 64-95
10000650: 00000000 00000040 00000000 ffffffff GPIO IRQ Risng Edge
10000660: 00000000 00000040 00010000 ffffffff GPIO IRQ Falling Edge
10000670: 00000000 00000000 00000000 ffffffff GPIO IRQ Level High
10000680: 00000000 00000000 00000000 ffffffff GPIO IRQ Level Low
10000690: 00000000 00000000 00000000 ffffffff GPIO Interrupt Status
100006a0: 00000000 00000000 00000000 ffffffff GPIO Edge Status
The interrupt appears on GPIO 16 on the third bank (0x00010000).
I tried GPIO 15 and the value changed to 0x00008000. So it's all
about the GPIO bank.
It looks like that the problem is located in gpio-mt7621.c, where the GPIO
banks are not corresponding correctly with device tree settings.
To be honest I'm not very familiar with device tree bindings to the kernel.
Does anybody have a hint how I could fix it ?