On Thu, Nov 15, 2018 at 09:30:40AM +0100, Adam Rudziński wrote: > W dniu 2018-11-15 o 08:36, Uwe Kleine-König pisze: > > Hello, > > > > On Wed, Nov 14, 2018 at 11:33:25PM +0100, Adam Rudziński wrote: > > > returning to our discussion on incorrect handling of CTSb used as "driver > > > enable" by SERIAL_IMX driver in RS485 mode, I've made the fix I was able to, > > > ie. the simple one with just keeping the receiver of the UART on. Eventually > > > this got tested in action and worked fine. > > > > > > The kernel I used is a version of ancient 4.14.39, possibly with some > > > vendor-specific patches. I tried to compare it with the most recent > > > long-term 4.14.81, but there are changes which I can't interpret without > > > deeper studies (however, it seems to me that the original problem would > > > still be present). Newer kernels have even more differences. > > > > > > If such fix could be useful, and somebody feels like undertaking the effort > > > to implement it in a proper way, the fix can be found under this address > > > (along with a short description): > > > http://arf.net.pl/iMX6/RS485fix.html > > How does the relevant part of your dts look like? Did you try to use a > > gpio instead of the hardware function "CTS" as rts? > > > > Best regards > > Uwe > > It goes like this, first in dtsi: > > &uart5 { > pinctrl-names = "default"; > pinctrl-0 = <&pinctrl_uart5>; > uart-has-rtscts; > status = "disabled"; > }; > > and then in dts for the board: > > &uart5 { > rs485-rts-active-high; > linux,rs485-enabled-at-boot-time; > status = "okay"; > }; Then try adding rts-gpios = <&gpio1 6 GPIO_ACTIVE_LOW>; to your board's dts and adapt the pinctrol accordingly to configure the cts pin to it's GPIO function instead of CTS. There should be no need to adapt the driver for that. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
