unable to enable UART2 on BBB.

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1

HI All,

I am trying to enable UART2 on beaglebone black.

I have made below changes in am335x-bone-common.dtsi file but I am not able to see any prints related to UART2 in dmesg logs.

uart2_pins: uart2_pins {
pinctrl-single,pins = <
AM33XX_IOPAD(0x954, PIN_OUTPUT_PULLDOWN | MUX_MODE1) /* spi0_d0.uart2_tx /
AM33XX_IOPAD(0x950, PIN_INPUT_PULLUP | MUX_MODE1) / spi0_sclk.uart2_rx */

;
};

&uart2 {
pinctrl-names = “default”;
pinctrl-0 = <&uart2_pins>;

compatible = “free-electrons, serial”;

status = “okay”;
};

I recompiled the dts file and generated new dtb, and loaded this dtb file. but no luck.

when I grep for the uart’s in dmesg log it showing only one uart

ubuntu@ubuntu-armhf:~$ dmesg | grep uart
[ 0.526979] omap_uart 44e09000.serial: no wakeirq for uart0

what could be issue.

Thanks & regards,
Madhu

2

HI All,

I am trying to enable UART2 on beaglebone black.

I have made below changes in am335x-bone-common.dtsi file but I am not able
to see any prints related to UART2 in dmesg logs.

        uart2_pins: uart2_pins {
                pinctrl-single,pins = <
                        AM33XX_IOPAD(0x954, PIN_OUTPUT_PULLDOWN | MUX_MODE1)
/* spi0_d0.uart2_tx */
                        AM33XX_IOPAD(0x950, PIN_INPUT_PULLUP | MUX_MODE1) /*
spi0_sclk.uart2_rx */
                >;
        };

&uart2 {
        pinctrl-names = "default";
        pinctrl-0 = <&uart2_pins>;

        compatible = "free-electrons, serial";

this is wrong ^ remove the compatible line..

        status = "okay";
};

I recompiled the dts file and generated new dtb, and loaded this dtb file.
but no luck.

when I grep for the uart's in dmesg log it showing only one uart

ubuntu@ubuntu-armhf:~$ dmesg | grep uart
[ 0.526979] omap_uart 44e09000.serial: no wakeirq for uart0

what could be issue.

Regards,

3

Well because it's wrong for this hardware, and you are overwriting the
actual compatible string:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am33xx.dtsi#n285

Regards,