UART2 issue in wandboard quad!!

[dtvs]

I'm trying to use the UART-2 Ports on Wand Board Quad(Ver C1). I have modified the imx6qdl.dtsi and imx6qdl-wandboard.dtsi file for enabling the UART2 port on the Wandboard-Quad.After executing commands
--> cat /dev/ttymxc1 &
-->echo 1234567890 > /dev/ttymxc1
But I'm not getting the echo response for the command executed.(pin 6 --U2_RXand pin 14-U2_TX are shorted ).

*************************************

below path location of git where the changes were made
************************************************************
/home/lablinux/fsl-community-bsp/build/tmp/work/wandboard_quad-poky-linux-gnueabi/linux-wandboard/3.10.17-r0/git/arch/arm/boot/dts

Below Changes done in sourcefile --> imx6qdl.dtsi
--------------------------------------------
pinctrl_uart2_3: uart2grp-3 { /* DTE mode */
            fsl,pins = <
                MX6QDL_PAD_SD4_DAT4__UART2_RX_DATA 0x1b0b1
                MX6QDL_PAD_SD4_DAT5__UART2_RTS_B   0x1b0b1
                MX6QDL_PAD_SD4_DAT6__UART2_CTS_B   0x1b0b1
                MX6QDL_PAD_SD4_DAT7__UART2_TX_DATA 0x1b0b1
            >;
        };

below path location of git where the changes were made (imx6qdl-wandboard.dtsi)
------------------------------------------------------
pinctrl_gpio: commented this two pins.
/*MX6QDL_PAD_EIM_D27__GPIO3_IO27 0x4001b0b0 /* GPIO3_27 EDM pin 258 */
/*MX6QDL_PAD_EIM_D26__GPIO3_IO26 0x4001b0b0 /* GPIO3_26 EDM pin 259 */

added below to support uart2

&uart2 {
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_uart2_3>;
status = "okay";
};

After making the above changes i executed the below commands

-->bitbake -c devshell virtual/kernel (From build directory /home/lablinux/fsl-community-bsp/build)

-->make dtbs (from /home/lablinux/fsl-community-bsp/build/tmp/work/wandboard_quad-poky-linux-gnueabi/linux-wandboard/3.10.17-r0/git/)

-->bitbake -c deploy -f virtual/kernel (From build directory /home/lablinux/fsl-community-bsp/build).

then executed

-->bitbake core-image-minimal (From build directory /home/lablinux/fsl-community-bsp/build)

After this loaded the core-image-minimal.sdcard on the SD card using the dd command.

I am able to see the ttymxc1 after executing ls /dev.

But after executing below commands

--> cat /dev/ttymxc1 &
-->echo 1234567890 > /dev/ttymxc1

i am not seeing the echoing (Shorting of tx and rx taken care).(Also ran a serial test and observed the TX(14 pin) line on Oscilloscope no signals are appearing).

Used as reference the below link-->Wandboard Discussion Forums • View topic - Enable Second UART (Kernel 3.10 with Device Tree) 

Please let me know above steps followed for dtsi changes are correct.??and why tthe communication is not happening..

[igorpadykov]

Hi harsh

regarding " the TX(14 pin) line on Oscilloscope no signals are appearing" -

in "DTE" mode as shown on pinctrl_uart2_3, TX is input according to

Table 90. UART I/O Configuration vs. Mode i.MX6DQ Datasheet

http://www.nxp.com/docs/en/data-sheet/IMX6DQCEC.pdf

In general one can attach jtag debugger and test uart writing to its registers.

Example of uart2 dts can be found on :

linux-2.6-imx.git - Freescale i.MX Linux Tree 

Best regards
igor
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[dtvs]

Thank you for the reply.

I was able to see the echo on the terminal after making the following changes.

In the imx6qdl_wandboard.dtsi For uart2 previously we had written as below.

&uart2 {      pinctrl-names = "default";      pinctrl-0 = <&pinctrl_uart2_3>;      status = "okay"; };
**********************
and in the file imx6qdl.dtsi we had created a group as below
pinctrl_uart2_3: uart2grp-3 { /* DTE mode */                fsl,pins = <                     MX6QDL_PAD_SD4_DAT4__UART2_RX_DATA   0x1b0b1                     MX6QDL_PAD_SD4__DAT5_UART2_RTS_B   0x1b0b1                     MX6QDL_PAD_SD4__DAT6_UART2_CTS_B 0x1b0b1                     MX6QDL_PAD_SD4__DAT7_UART2_TX_DATA 0x1b0b1                >;           };
But the changes didn't work.

So i changed the imx6qdl_wandboard.dtsi to below 
&uart2 {      pinctrl-names = "default";      pinctrl-0 = <&pinctrl_uart2_1>;      status = "okay"; };
and after this i was able to see the UART2 working.Verfied by the echo test.
Then verfied with the scope also.
And below were the dtsi configuration for uart2 group-1 in imx6qdl.dtsi

uart2 {           pinctrl_uart2_1: uart2grp-1 {                fsl,pins = <                     MX6QDL_PAD_EIM_D26__UART2_TX_DATA 0x1b0b1                     MX6QDL_PAD_EIM_D27__UART2_RX_DATA 0x1b0b1                >;           };