Adding GPIO to device tree overlay

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Hi Richard,

It looks like you’ve made significant progress in setting up your device tree overlay for the Verdin AM62 module. However, there are a few things you might want to check to ensure that your GPIOs are correctly configured and functional.

  1. Check Pin Multiplexing and Conflicts:

    • Ensure that the pins you are trying to use as GPIOs are not being used by any other peripherals. You can do this by inspecting the base device tree files and making sure that no other nodes are referencing these pins.

  2. Pin Control Node Configuration:

    • Make sure that the pin control node is correctly defined and referenced. For example, you have defined pinctrl_gateway_board_inputs and pinctrl_gateway_board_outputs but ensure that these are correctly referenced in the appropriate nodes.

  3. GPIO Direction and Initial State:

    • Ensure that the GPIO direction is set correctly (input/output) and that the initial state is defined if necessary. For example, you can set the direction and initial state in the device tree overlay.

  4. Check GPIO Export and Permissions:

    • Verify that the GPIOs are exported correctly and that you have the necessary permissions to manipulate them. You can check the /sys/class/gpio directory to see if the GPIOs are exported and accessible.

  5. Debugging with gpio Command:

    • Use the gpio command to debug and manipulate the GPIOs. For example, you can use gpio readall to see the current state of all GPIOs and gpio write to set the state of a specific GPIO.

Here is a simplified example of how you might define and reference GPIOs in your device tree overlay:

&main_pmx0 {
    pinctrl_gpio: gpio_pins {
        pinctrl-single,pins = <
            AM62X_IOPAD(0x00C, PIN_INPUT, 7) /* GPIO0_3 */
            AM62X_IOPAD(0x0010, PIN_INPUT, 7) /* GPIO0_4 */
            // Add other GPIOs here
        >;
    };
};

&main_gpio0 {
    pinctrl-names = "default";
    pinctrl-0 = <&pinctrl_gpio>;
    status = "okay";
};

Make sure to replace the AM62X_IOPAD values with the correct ones for your specific pins.

  1. Rebuild and Apply the Overlay:
    • After making the necessary changes, rebuild the device tree overlay and apply it using the TorizonCore Builder Tool. Ensure that the overlay is correctly loaded at boot.

If you have followed these steps and the GPIOs are still not functioning as expected, you might want to check the hardware connections and ensure that there are no issues with the physical pins.

If you need further assistance, please provide more details about the specific errors or issues you are encountering, and I will be happy to help.

Kind regards,
[Your Name]

Please, also check if these links can help you solve your problem:

Pin multiplexing on AM62.