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i.MX6Q UART5 CTS as input

Question asked by Anders Tornqvist on Mar 14, 2014
Latest reply on Mar 20, 2014 by jimmychan

How shall UART5 be configured for correct operation with RTS/CTS?

 

As on the SABRESDB board where an external Bluetooth device can be connected to UART5, I have a device connected.

 

The device has a RTS output connected to iMX6 KEY_ROW4 where this iMX pin should operate as input.

 

For my Linux kernel I have a DTS configuration like this:

&iomuxc {

    uart5 {

        pinctrl_uart5_1: uart5grp-1 {

            fsl,pins = <

                MX6QDL_PAD_KEY_ROW4__UART5_CTS_B 0x1b0b1  /* UART5_CTS */

                MX6QDL_PAD_KEY_COL4__UART5_RTS_B 0x1b0b1  /* UART5_RTS */

                >;

        };

    };

};

 

&uart5 {

    compatible = "fsl,imx6q-uart", "fsl,imx21-uart";

    pinctrl-names = "default";

           pinctrl-0 = <&pinctrl_uart5_1>;

        //fsl,uart-has-rtscts;

        //fsl,dte-mode;

    status = "okay";

};

 

This configuration makes the KEY_ROW4 pad as output which collides with the RTS output from the external device.

 

If I understand the iMX6 reference manual correct this is also the case since UART5 is in DCE mode default.

Therefore I have also added "fsl,dte-mode" as above and uncommented it. No difference.

 

How shall I configure the DTS for appropriate function (input) on the KEY_ROW4 pad?

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