Attached is a git diff, which includes 2 patches:
rs485-8250_dw.patch - manually merged for 5.13.3
[PATCH] tty: 8250_of: Use software emulated RS485 direction control @ 2019-09-13 5:01 Heiko Schocher
As you can see it's for the current/latest armbian kernel version 5.13.3 . I haven't re-applied the patch to see if patching works but with these changes RS485 works great for me on my NanoPI Neo.
I don't use any additional ENV-vars for booting, but this DTS::
/dts-v1/;
/plugin/;
/ {
compatible = "allwinner,sun8i-h3";
fragment@0 {
target = <&uart2>;
__overlay__ {
pinctrl-names = "default";
pinctrl-0 = <&uart2_pins>;
linux,rs485-enabled-at-boot-time;
rs485-rts-active-low;
//rs485-rx-during-tx;
rts-gpios = <&pio 0 2 1>;
status = "okay";
};
};
};
This took me 3 days but I wouldn't get it running without this forum.
erazor got a reaction from Igor in RTS signal and uart2 init