Change Device Tree Beaglebone Black

General Discussion
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1

I’m attempting to learn about the device tree. I am starting by just modifying my existing device tree. In this case that’s here in the kernel-source directory

tmp/work-shared/beaglebone-yocto/kernel-source/arch/arm/boot/dts/am335x-bone-common.dtsi. I added this to the am33xx_pinmux section

&am33xx_pinmux {
pinctrl-names = “default”;
pinctrl-0 = <&clkout2_pin>;

    ui_button_pins: ui_button_pins {
            pinctrl-singl,pins = <
                    AM33XX_PADCONF(AM335X_PIN_GPMC_A1, PIN_OUTPUT, MUX_MODE7)/* (U13) gpmc_a1.gpio1_17 */
                    AM33XX_PADCONF(AM335X_PIN_GPMC_AD10, PIN_OUTPUT, MUX_MODE7)/* (U13) gpmc_a1.gpio0_26 */
                    AM33XX_PADCONF(AM335X_PIN_GPMC_AD14, PIN_OUTPUT, MUX_MODE7)/* (U13) gpmc_a1.gpio1_14 */
                    AM33XX_PADCONF(AM335X_PIN_MCASP0_FSR, PIN_OUTPUT, MUX_MODE7)/* (U13) MCASP0_FSR.gpio3_19 */
            >;
    };

I’m expecting to see a change in root@beaglebone-yocto:/sys/kernel/debug/pinctrl/44e10800.pinmux-pinctrl-single

but I do not. What am I missing?

2

You are only declaring the pin mux but not instantiating it.

In

You need to add your pinmux after clkout2_pin. Separate by a space

1 Like
3

I’m not sure what my pinmux is?

4

^ that… :wink:

pinctrl-0 = <&clkout2_pin &ui_button_pins>;

Regards,

1 Like
5

thanks @benedict.hewson @RobertCNelson that did it