PCIe FFC interface of Dual 2.5GbE router hat is not working

[overflow]

I solved this problem, this is link :

Dual 2.5G Router HAT - FPC Connector use

I’ve confirmed the root cause and the issue is now solved. On the ROCK 4D, physical pin 16 is GPIO2_B6. With the default OpenWrt device tree, this GPIO stayed as an input/LOW. I measured: 40-pin GPIO16: 0 V FPC pin 13 (POWER_EN): 0 V When I manually drove GPIO16 HIGH from userspace: gpioset -c gpiochip2 14=1 both GPIO16 and FPC pin 13 changed to about 3.3 V, the PWR LED on the ASM1182E board turned on, and the ASM1182E immediately appeared in lspci: 04:00.0 PCI bridge: ASMedia Technology …