Defining IO pin in zephyr

[cmag]

I am trying to define a simple output pin.

in the DTS file I have:

aliases {

        ledred = &hwledred;

        ledgreen = &hwledgreen;

        memwp = &hwmemwp;

    };

    soc {

        gpio0: gpio@50000000 {

            status = "okay";

        };

    };

    chosen {

        zephyr,sram = &sram0;

        zephyr,flash = &flash0;

        zephyr,code-partition = &slot0_partition;

    };

    leds {

        compatible = "gpio-leds";

        hwledred: led_red {

            gpios = <&gpio0 2 GPIO_ACTIVE_LOW>;

        };

        hwledgreen: led_green {

            gpios = <&gpio0 3 GPIO_ACTIVE_LOW>;

        };

    };

    zephyr,user {

        hwmemwp: mew_wp {

            gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;

            label = "mem WP";

        };

    };

The LED definitions are working fine, but I cannot get a way to define the mem_wp pin in the C code.

The following compiles, but the values in the generated structure are meaningless and the program crashes.

#define ZEPHYR_USER_NODE DT_PATH(zephyr_user)

#define WP DT_ALIAS(memwp)

#if !DT_NODE_HAS_STATUS_OKAY(WP)

#error "Unsupported board: WP devicetree alias is not defined"

#endif

const struct gpio_dt_spec memWP = GPIO_DT_SPEC_GET_OR(WP, gpios, {0});

What is the correct way to define and use a simple IO pin?

[AHaug]

Hi,

In the zephyr,user node you've written "mew_wp". Shouldn't this also be mem_wp or memwp depending on the alias you decided to use??

Have you defined this device binding somewhere? I can't see the device binding for any memwp within the SDK

Kind regards,
Andreas

[cmag]

For the red LEDs I have:
hwledred linked to ledred and referenced in C as:

#define LED_RED_NODE DT_ALIAS(ledred)
static const struct gpio_dt_spec ledRed = GPIO_DT_SPEC_GET(LED_RED_NODE, gpios);

I expected that the analogous for WP should be:
hwmemwp linked to memwp and referenced in C as:

#define WP DT_ALIAS(memwp)
const struct gpio_dt_spec memWP = GPIO_DT_SPEC_GET_OR(WP, gpios, {0});

Should work in the same way.
But I am obviously missing something.
I have found direct pin control samples in Internet, but when I try them I get a long chain of errors concerning macros calling more macros.
For this I am asking of a simple example of a DTS defining a pin and the C file referencing it.

[AHaug]

Hi, 

Apologies for the response time.

cmag said:

I have found direct pin control samples in Internet,

Could you share a link to this sample? You might be missing some configurations if there's a mismatch between the sample and the SDK version you're using

Kind regards,
Andreas