UART rts/cts handshaking failure

[hello-world123]

Hello, I'm john and currently doing uart to control bluetooth module and I have difficulties to use UART with rts/cts.

 Without rts/cts setting in device-tree + hardware(connect bluetooth module's CTS to GND + open RTS), hciattach works. But with rts/cts, timeout occurs when do hciattach.

I think I use rts/cts device tree unproperly. The following's are my dts settings.

Above picture UART1_RTS_B & UART1_CTS_B is 0x6 to tune data like pad things. (I used 0x140 as default)

When I type hciattach, i.mx's RTS doesn't assert as low. I think this is the reason why It's not working.

Does my device tree correct? Should I use 'uart-has-rtscts' instead of 'fsl,uart-has-rtscts'?

Thanks.

[igorpadykov · Accepted solution]

Hi Daewoong

for rts/cts example one can look at below &uart3 { /* BT */ :

https://source.codeaurora.org/external/imx/linux-imx/tree/arch/arm64/boot/dts/freescale/imx8mq-evk.d...

For uart1 issue, just for test one can try to remove "dma" entries in dts.

Best regards
igor