Kernel 4.1 ( no cap ) & RS485

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1

Hi,

I’m trying to make rs485 working on the kernel 4.1 :

&uart1 {
pinctrl-names = “default”;
pinctrl-0 = <&uart1_pins>;
status = “okay”;
rts-gpio = <&gpio0 27 GPIO_ACTIVE_HIGH>;
rs485-rts-active-high;
rs485-rts-delay = <1 1>;
linux,rs485-enabled-at-boot-time;
};

but in the boot log I have :

[ 2.961866] 48022000.serial: ttyS1 at MMIO 0x48022000 (irq = 155, base_baud = 3000000) is a 8250

does it mean that it’s the driver 8250 that handle this uart ?

If it’s the case, that not good, because only the driver omap handle rs485.

When I’m trying to configure the RS485 port, I have the errno = 25 = Not a typewriter

Micka,

2

switch back to the old omap_serial.c driver

The new omap_8250 still needs to be extended to rs485..

Regards,

3

8250 is the uart type its a serial device

rs485 denotes a differential serial hardware layer

you still need the 8250 driver to talk serial

4

btw see this thread:

http://lists.infradead.org/pipermail/linux-arm-kernel/2014-April/250143.html

Since you've done a lot with rs485 i think you can help extend
omap_8250 for rs485.. (the 8250 already has rs485 support, and with
the mctrl_gpio helpers it should be easy-ish..)

Regards,

5

looks like infradead dropped the last message:

http://www.spinics.net/lists/linux-omap/msg118854.html

Regards,

6

Yes, that’s a good idea, I will look into the driver 8250 soon.