How to patch/change dts for some GPIO pins (linux 5.4)

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droland

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Jun 25, 2020, 9:26:00 AM6/25/20

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Hello,

I have a linux 5.4 custom build (by BuildRoot) for BeagleBone Black. There is no device-tree overlay and cape manager...

I need some inputs and outputs so I should create a patch for the am335x-boneblack-common.dtsi file (and probably for am335x-boneblack.dts too) that's way I have added some lines to am335x-boneblack-commom.dtsi into the "&am33xx_pinmux" section:

&am33xx_pinmux {


...


gpio_pins: pinmux_gpio_pins {
        pinctrl-single,pins = <
            AM33XX_PADCONF(AM335X_PIN_MCASP0_FSR, PIN_OUTPUT, MUX_MODE7) /* control pin1 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_A1, PIN_OUTPUT, MUX_MODE7) /* control pin2 */
            
            AM33XX_PADCONF(AM335X_PIN_GPMC_OEN_REN, PIN_INPUT_PULLUP, MUX_MODE7) /* SW1 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_ADVN_ALE, PIN_INPUT_PULLUP, MUX_MODE7) /* SW2 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_WEN, PIN_INPUT_PULLUP, MUX_MODE7) /* SW3 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_BEN0_CLE, PIN_INPUT_PULLUP, MUX_MODE7) /* SW4 */

            AM33XX_PADCONF(AM335X_PIN_GPMC_CSN0, PIN_INPUT_PULLUP, MUX_MODE7) /* Rev0 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_CLK, PIN_INPUT_PULLUP, MUX_MODE7) /* Rev1 */
            
            AM33XX_PADCONF(AM335X_PIN_GPMC_AD10, PIN_INPUT_PULLUP, MUX_MODE7) /* input1 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_AD15, PIN_INPUT_PULLUP, MUX_MODE7) /* input2 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_AD14, PIN_INPUT_PULLUP, MUX_MODE7) /* input3 */
            AM33XX_PADCONF(AM335X_PIN_GPMC_AD11, PIN_INPUT_PULLUP, MUX_MODE7) /* input4 */
        >;
    };

};

It has no effect. The "input pull up" does not work. I have read a lot of articles and projects, but I don't know how I should do it.I have stucked here.

Please help me with an example or any other way to make those inputs and outputs work .

Thank you in advance.

droland

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Jul 1, 2020, 9:19:46 AM7/1/20

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I have added the following to the am335x-boneblack.dts:

&am33xx_pinmux {
    pinctrl-names = "default";
    pinctrl-0 = <&gpio_pins>;

    status = "okay";  
};