IMX8MP Linux: Using GPIO for RTS/CTS on UART3

[mahesh_hns]

Hi,

 I have a board with imx8mp running linux 5.4 . I would like to configure UART3 however with GPIO64/65 as RTS/CTS pins. Would that be possible? Is there any restriction to what GPIO pins can be used for RTS/CTS.(in other words, can I use ANY GPIO pins for RTS/CTS and hook it up to the uart3 in device tree as done in the below forum link?) I see an query below for imx8mQ which is similar, but unanswered.

Is the configuration mentioned here similar to what I am looking for?

https://community.nxp.com/t5/i-MX-Processors/Use-GPIO-Pins-as-RTS-and-CTS-for-UART/m-p/1436268#M1887...

Thanks

Regards

[Zhiming_Liu]

Hi @mahesh_hns 

You can search in arch/arm64/boot/dts/freescale/imx8mp-pinfunc.h. There are only two pads can support RTS/CTS on UART3, they are MX8MP_IOMUXC_ECSPI1_MISO__UART3_DCE_CTS and 

MX8MP_IOMUXC_SD1_STROBE__UART3_DCE_CTS.

can I use ANY GPIO pins for RTS/CTS and hook it up to the uart3 in device tree as done in the below forum link?

-->SOC design has decided that you can't.

Best Regards

Zhiming