RK3288 UART4 wrong defined at rk3288.dtsi

[armoreno]

I want to enable the UART4 in my RK3288-Firefly board but it is not working at real pins level, although it does appear at kernel level as /dev/ttyS4.

I've disabled the SPI0 node in the rk3288-firefly.dtsi file as follows:

&spi0 {
   pinctrl-names = "default";
   pinctrl-0 = <&spi0_clk>, <&spi0_cs0>, <&spi0_tx>, <&spi0_rx>, <&spi0_cs1>;
   status = "disabled";
};

And I've enabled the UART4 as follows:

&uart4 {
    status = "okay";
};

Then I've also checked with dmesg the UART4 is probed:
[ 1.177999] ff1c0000.serial: ttyS4 at MMIO 0xff1c0000 (irq = 40, base_baud = 1500000) is a 16550A

Also checked:

root@ubuntu:~# cat /sys/firmware/devicetree/base/serial\@ff1c0000/status
okay

And:

root@ubuntu:~# cat /sys/firmware/devicetree/base/spi\@ff110000/status
disabled

But when I write some characters to the UART4 using:

stty -F /dev/ttyS4 115200
echo hello world > /dev/ttyS4

Nothing is read from the pins side...
Therefore I think the UART4 node is wrong defined at the rk3288.dtsi file level.

[armoreno]

Does anybody have any idea or suggestion about how to fix the UART4 problem with the Firefly-RK3288 board?

Many thanks in advance!

[armoreno]

Well, finally I got the UART4 is working.
The rk3288.dtsi pinctrl assignment is wrong. The right pins for the UART4 are:
Rx: 5 - 15
Tx: 5 - 14
CTS: 5 - 12
RTS: 5 - 13

[wzyy2]

What about sending the patch to [email protected]?
https://www.kernel.org/doc/html/v4.12/process/submitting-patches.html

[armoreno]

I was not sure where to send it... So, now I will send a patch soon.