extra gpios in board overlay for nrf9160dk

[paul_tanner]

I need a gpio to control an external peripheral.

I thought to code should be similar to controlling one of the leds.

board overlay:

&gpio17 {
  status = "okay"
  gpio17: gpio_17 {
    gpios = <&gpio0 17 0>;
    label = "PUP";
  };
}

Source:

#define PUP_NODE DT_ALIAS(gpio17)
#if DT_NODE_HAS_STATUS(PUP_NODE, okay)
#define PUP DT_GPIO_LABEL(PUP_NODE, gpios)
#define PUP_PIN DT_GPIO_PIN(PUP_NODE, gpios)
#define PUP_FLAGS DT_GPIO_FLAGS(PUP_NODE, gpios)
#else
#error "Unsupported board: gpio17 devicetree alias is not defined"
#endif

const struct device *power_up = device_get_binding(PUP);
gpio_pin_configure(power_up, PUP_PIN, GPIO_OUTPUT_ACTIVE | PUP_FLAGS);
gpio_pin_set(power_up, PUP_PIN, (int)power_up_is_on);

building this with west gives me a syntax error related to the overlay

I don't understand how overlays should define additional gpios beyond the standard ones for leds.

Any advice please?

[Albrecht Markus Schellenberger]

Hello Paul,

The syntax error is due to a missing “/ { };”. And “customa: customb” should be ” customb: customb”. instead.

Here is another example:

/ {
    gpiocustom {
        compatible = "gpio-keys";
        gpiocus0: gpiocus_0 {
            gpios = <&gpio0 28 GPIO_ACTIVE_LOW>;
            label = "Custom gpio 28";
        };
        gpiocus1: gpiocus_1 {
            gpios = <&gpio0 29 GPIO_ACTIVE_LOW>;
            label = "Custom gpio 29";
        };
    };
    aliases {
        gpiocus0 = &gpiocus0;
        gpiocus1 = &gpiocus1;
    };
};

I hope this works for you.

Regards,

Markus

[paul_tanner]

Many thanks Markus

I did notice the use of \ notation in overlays but did not understand what it was trying to do.

Anyway, that fix works.

If there is any documentation on .dts syntax it would be good to study that rather than try to rely on examples only.

[Albrecht Markus Schellenberger]

Good to hear that the fix works, Paul.

There is plenty of documentation around the .dts syntax, you can for instance have a look here:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.5.0/zephyr/guides/dts/index.html

Cheers!

Markus