Getting started with gpio overlay

[garrettb]

Hi

I am really struggling to get started with overlay files. I have read through a lot of documentation, watched a few hours of YouTube tutorials, and yet I can’t even get going with one gpio.

I have an existing project for the nRF5340_DK, based I think on Nordic’s BLE UART Peripheral example.
I had to change the pins used for the i2c bus, so I managed to hack an overlay fiel for that, which works – but probably isn’t correct.
So now I want to try using one of the GPIO, as an output.

The examples I found were here and here.

I couldn't get either to build.

Any help / guidance / pointers would be appreciated, thank you.

DETAILS

I decided to pick gpio0.25, and then gpio0.26, since they seem to be free.

Here is my overlay file – you will see both attempts at the end of the file – one commented out:

/*
 * Copyright (c) 2022 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

/ {
	chosen {
		nordic,nus-uart = &uart0;
	};
};


&pinctrl {
	i2c2_default: i2c2_default {
		group1 {
			psels = <NRF_PSEL(TWIM_SCL, 0, 6)>, <NRF_PSEL(TWIM_SDA, 0, 7)>;
		};
	};

	i2c2_sleep: i2c2_sleep {
		group1 {
			psels = <NRF_PSEL(TWIM_SDA, 0, 7)>,
				<NRF_PSEL(TWIM_SCL, 0, 6)>;
			low-power-enable;
		};
	};
};

&i2c2 {
	compatible = "nordic,nrf-twim";
	status = "okay";


	pinctrl-0 = <&i2c2_default>;
	pinctrl-1 = <&i2c2_default>;
	pinctrl-names = "default", "sleep";
};


&uart0_default {
	group2 {
		psels = <NRF_PSEL(UART_RX, 0, 22)>, <NRF_PSEL(UART_CTS, 0, 21)>;
	};
};

&uart0_default {
	group1 {
		psels = <NRF_PSEL(UART_RTS, 0, 19)>;
	};
};

// !gpio! - start
// From example here: https://devzone.nordicsemi.com/f/nordic-q-a/94963/need-simple-devicetree-overlay-example-for-gpio
/*
/{

	custom_gpios {
 
	   compatible = "gpio-keys";
 
	   cusgpio0: cusgpio_0 {
 
		  gpios = <&gpio0 25 GPIO_ACTIVE_HIGH>;
 
		  label = "My custom GPIO";
 
	   };
 
	};
 
	aliases {
 
	mycusgpio = &cusgpio0;
	};
 
 };

// From example here: https://devzone.nordicsemi.com/f/nordic-q-a/72618/extra-gpios-in-board-overlay-for-nrf9160dk
*/
/ {
    gpiocustom {
        compatible = "gpio-keys";
        gpiocus0: gpiocus_0 {
            gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
            label = "Custom gpio 25";
        };
        gpiocus1: gpiocus_1 {
            gpios = <&gpio0 26 GPIO_ACTIVE_LOW>;
            label = "Custom gpio 26";
        };
    };
    aliases {
        gpiocus0 = &gpiocus0;
        gpiocus1 = &gpiocus1;
    };
};
// !gpio! – end

And in main.c, again – two attempts, one commented out:

// !gpio! - start
//#define GPIO025_NODE  DT_ALIAS(mycusgpio)
//#define GPIO025           DT_GPIO_LABEL(GPIO025_NODE, gpios)
#define GPIO025_NODE    DT_ALIAS(gpiocus0)
#define GPIO025         DT_GPIO_LABEL(GPIO025_NODE, gpios)
// !gpio! - end

And in main():

    const struct device *dev_gpio0;                 // !gpio!

    dev_gpio0 = device_get_binding(GPIO025);        // !gpio!

Here are the warnings and errors I get for the first build (for gpio0.25 only – which is the attempt commented out above):

src\main.c:213:13: warning: Macro is deprecated
  213 |  dev_gpio0 = device_get_binding(GPIO025);
      |             ^~~~~~~~~~~~~~~~~~~~~
 build\zephyr\include\generated\devicetree_unfixed.h:1749:58: error: 'DT_N_S_soc_S_peripheral_40000000_S_gpio_842500_P_label' undeclared (first use in this function); did you mean 'DT_N_S_soc_S_peripheral_40000000_S_gpio_842500_P_reg'?
 1749 | #define DT_N_S_custom_gpios_S_cusgpio_0_P_gpios_IDX_0_PH DT_N_S_soc_S_peripheral_40000000_S_gpio_842500
      |                                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in definition of macro 'DT_CAT'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:2: note: in expansion of macro 'DT_PROP'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3076:41: note: in expansion of macro 'DT_N_S_custom_gpios_S_cusgpio_0_P_gpios_IDX_0_PH'
 3076 | #define DT_CAT6(a1, a2, a3, a4, a5, a6) a1 ## a2 ## a3 ## a4 ## a5 ## a6
      |                                         ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:1247:2: note: in expansion of macro 'DT_CAT6'
 1247 |  DT_CAT6(node_id, _P_, prop, _IDX_, idx, _PH)
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:54:2: note: in expansion of macro 'DT_PHANDLE_BY_IDX'
   54 |  DT_PHANDLE_BY_IDX(node_id, gpio_pha, idx)
      |  ^~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:10: note: in expansion of macro 'DT_GPIO_CTLR_BY_IDX'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |          ^~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:120:2: note: in expansion of macro 'DT_GPIO_LABEL_BY_IDX'
  120 |  DT_GPIO_LABEL_BY_IDX(node_id, gpio_pha, 0) __DEPRECATED_MACRO
      |  ^~~~~~~~~~~~~~~~~~~~
 src\main.c:64:19: note: in expansion of macro 'DT_GPIO_LABEL'
   64 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                   ^~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in expansion of macro 'DT_N_ALIAS_mycusgpio'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:213:25: note: in expansion of macro 'DT_CAT'
  213 | #define DT_ALIAS(alias) DT_CAT(DT_N_ALIAS_, alias)
      |                         ^~~~~~
 src\main.c:63:22: note: in expansion of macro 'DT_ALIAS'
   63 | #define GPIO025_NODE DT_ALIAS(mycusgpio)
      |                      ^~~~~~~~
 src\main.c:64:33: note: in expansion of macro 'GPIO025_NODE'
   64 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                                 ^~~~~~~~~~~~
 src\main.c:213:33: note: in expansion of macro 'GPIO025'
  213 |  dev_gpio0 = device_get_binding(GPIO025);   
      |                                 ^~~~~~~
 build\zephyr\include\generated\devicetree_unfixed.h:1749:58: note: each undeclared identifier is reported only once for each function it appears in
 1749 | #define DT_N_S_custom_gpios_S_cusgpio_0_P_gpios_IDX_0_PH DT_N_S_soc_S_peripheral_40000000_S_gpio_842500
      |                                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in definition of macro 'DT_CAT'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:2: note: in expansion of macro 'DT_PROP'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3076:41: note: in expansion of macro 'DT_N_S_custom_gpios_S_cusgpio_0_P_gpios_IDX_0_PH'
 3076 | #define DT_CAT6(a1, a2, a3, a4, a5, a6) a1 ## a2 ## a3 ## a4 ## a5 ## a6
      |                                         ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:1247:2: note: in expansion of macro 'DT_CAT6'
 1247 |  DT_CAT6(node_id, _P_, prop, _IDX_, idx, _PH)
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:54:2: note: in expansion of macro 'DT_PHANDLE_BY_IDX'
   54 |  DT_PHANDLE_BY_IDX(node_id, gpio_pha, idx)
      |  ^~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:10: note: in expansion of macro 'DT_GPIO_CTLR_BY_IDX'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |          ^~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:120:2: note: in expansion of macro 'DT_GPIO_LABEL_BY_IDX'
  120 |  DT_GPIO_LABEL_BY_IDX(node_id, gpio_pha, 0) __DEPRECATED_MACRO
      |  ^~~~~~~~~~~~~~~~~~~~
 src\main.c:64:19: note: in expansion of macro 'DT_GPIO_LABEL'
   64 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                   ^~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in expansion of macro 'DT_N_ALIAS_mycusgpio'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:213:25: note: in expansion of macro 'DT_CAT'
  213 | #define DT_ALIAS(alias) DT_CAT(DT_N_ALIAS_, alias)
      |                         ^~~~~~
 src\main.c:63:22: note: in expansion of macro 'DT_ALIAS'
   63 | #define GPIO025_NODE DT_ALIAS(mycusgpio)
      |                      ^~~~~~~~
 src\main.c:64:33: note: in expansion of macro 'GPIO025_NODE'
   64 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                                 ^~~~~~~~~~~~
 src\main.c:213:33: note: in expansion of macro 'GPIO025'
  213 |  dev_gpio0 = device_get_binding(GPIO025);   
      |                                 ^~~~~~~
[27/221] Building C object zephyr/drivers/mbox/CMakeFiles/drivers__mbox.dir/mbox_nrfx_ipc.c.obj
[29/219] Building C object modules/nrf/lib/dk_buttons_and_leds/CMakeFiles/..__nrf__lib__dk_buttons_and_leds.dir/dk_buttons_and_leds.c.obj
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1

And the error and warning for my second attempt:

../src/main.c: In function 'main':
src\main.c:215:13: warning: Macro is deprecated
  215 |  dev_gpio0 = device_get_binding(GPIO025);  // !gpio!
      |             ^~~~~~~~~~~~~~~~~~~~~
build\zephyr\include\generated\devicetree_unfixed.h:1752:56: error: 'DT_N_S_soc_S_peripheral_40000000_S_gpio_842500_P_label' undeclared (first use in this function); did you mean 'DT_N_S_soc_S_peripheral_40000000_S_gpio_842500_P_reg'?
 1752 | #define DT_N_S_gpiocustom_S_gpiocus_0_P_gpios_IDX_0_PH DT_N_S_soc_S_peripheral_40000000_S_gpio_842500
      |                                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in definition of macro 'DT_CAT'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:2: note: in expansion of macro 'DT_PROP'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3076:41: note: in expansion of macro 'DT_N_S_gpiocustom_S_gpiocus_0_P_gpios_IDX_0_PH'
 3076 | #define DT_CAT6(a1, a2, a3, a4, a5, a6) a1 ## a2 ## a3 ## a4 ## a5 ## a6
      |                                         ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:1247:2: note: in expansion of macro 'DT_CAT6'
 1247 |  DT_CAT6(node_id, _P_, prop, _IDX_, idx, _PH)
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:54:2: note: in expansion of macro 'DT_PHANDLE_BY_IDX'
   54 |  DT_PHANDLE_BY_IDX(node_id, gpio_pha, idx)
      |  ^~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:10: note: in expansion of macro 'DT_GPIO_CTLR_BY_IDX'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |          ^~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:120:2: note: in expansion of macro 'DT_GPIO_LABEL_BY_IDX'
  120 |  DT_GPIO_LABEL_BY_IDX(node_id, gpio_pha, 0) __DEPRECATED_MACRO
      |  ^~~~~~~~~~~~~~~~~~~~
src\main.c:66:19: note: in expansion of macro 'DT_GPIO_LABEL'
   66 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                   ^~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in expansion of macro 'DT_N_ALIAS_gpiocus0'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:213:25: note: in expansion of macro 'DT_CAT'
  213 | #define DT_ALIAS(alias) DT_CAT(DT_N_ALIAS_, alias)
      |                         ^~~~~~
src\main.c:65:22: note: in expansion of macro 'DT_ALIAS'
   65 | #define GPIO025_NODE DT_ALIAS(gpiocus0)
      |                      ^~~~~~~~
src\main.c:66:33: note: in expansion of macro 'GPIO025_NODE'
   66 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                                 ^~~~~~~~~~~~
src\main.c:215:33: note: in expansion of macro 'GPIO025'
  215 |  dev_gpio0 = device_get_binding(GPIO025);  // !gpio!
      |                                 ^~~~~~~
build\zephyr\include\generated\devicetree_unfixed.h:1752:56: note: each undeclared identifier is reported only once for each function it appears in
 1752 | #define DT_N_S_gpiocustom_S_gpiocus_0_P_gpios_IDX_0_PH DT_N_S_soc_S_peripheral_40000000_S_gpio_842500
      |                                                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in definition of macro 'DT_CAT'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:2: note: in expansion of macro 'DT_PROP'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3076:41: note: in expansion of macro 'DT_N_S_gpiocustom_S_gpiocus_0_P_gpios_IDX_0_PH'
 3076 | #define DT_CAT6(a1, a2, a3, a4, a5, a6) a1 ## a2 ## a3 ## a4 ## a5 ## a6
      |                                         ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:1247:2: note: in expansion of macro 'DT_CAT6'
 1247 |  DT_CAT6(node_id, _P_, prop, _IDX_, idx, _PH)
      |  ^~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:54:2: note: in expansion of macro 'DT_PHANDLE_BY_IDX'
   54 |  DT_PHANDLE_BY_IDX(node_id, gpio_pha, idx)
      |  ^~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:106:10: note: in expansion of macro 'DT_GPIO_CTLR_BY_IDX'
  106 |  DT_PROP(DT_GPIO_CTLR_BY_IDX(node_id, gpio_pha, idx), label) __DEPRECATED_MACRO
      |          ^~~~~~~~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree\gpio.h:120:2: note: in expansion of macro 'DT_GPIO_LABEL_BY_IDX'
  120 |  DT_GPIO_LABEL_BY_IDX(node_id, gpio_pha, 0) __DEPRECATED_MACRO
      |  ^~~~~~~~~~~~~~~~~~~~
src\main.c:66:19: note: in expansion of macro 'DT_GPIO_LABEL'
   66 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                   ^~~~~~~~~~~~~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:3068:24: note: in expansion of macro 'DT_N_ALIAS_gpiocus0'
 3068 | #define DT_CAT(a1, a2) a1 ## a2
      |                        ^~
C:\Users\me\ncs\v2.1.0\zephyr\include\zephyr\devicetree.h:213:25: note: in expansion of macro 'DT_CAT'
  213 | #define DT_ALIAS(alias) DT_CAT(DT_N_ALIAS_, alias)
      |                         ^~~~~~
src\main.c:65:22: note: in expansion of macro 'DT_ALIAS'
   65 | #define GPIO025_NODE DT_ALIAS(gpiocus0)
      |                      ^~~~~~~~
src\main.c:66:33: note: in expansion of macro 'GPIO025_NODE'
   66 | #define GPIO025   DT_GPIO_LABEL(GPIO025_NODE, gpios)
      |                                 ^~~~~~~~~~~~
src\main.c:215:33: note: in expansion of macro 'GPIO025'
  215 |  dev_gpio0 = device_get_binding(GPIO025);  // !gpio!
      |                                 ^~~~~~~
[27/222] Building C object zephyr/drivers/pinctrl/CMakeFiles/drivers__pinctrl.dir/pinctrl_nrf.c.obj
[29/220] Building C object zephyr/drivers/mbox/CMakeFiles/drivers__mbox.dir/mbox_nrfx_ipc.c.obj
[30/220] Building C object zephyr/drivers/entropy/CMakeFiles/drivers__entropy.dir/C_/Users/garrett/ncs/v2.1.0/nrf/drivers/entropy/entropy_cc3xx.c.obj
[31/220] Building C object modules/nrf/lib/dk_buttons_and_leds/CMakeFiles/..__nrf__lib__dk_buttons_and_leds.dir/dk_buttons_and_leds.c.obj
ninja: build stopped: subcommand failed.
FATAL ERROR: command exited with status 1

By the way, I don’t know where this came from, in the overlay file – I suspect is was from when I was playing with the Device Tree GUI:

&uart0_default {
	group2 {
		psels = <NRF_PSEL(UART_RX, 0, 22)>, <NRF_PSEL(UART_CTS, 0, 21)>;
	};
};

&uart0_default {
	group1 {
		psels = <NRF_PSEL(UART_RTS, 0, 19)>;
	};
};

[garrettb]

Hi

I feel like I am getting closer to a solution, but…

So here’s the code from my overlay:

/ {
    gpiocustom {
        compatible = "gpio-keys";
        gpiocus0: gpiocus_0 {
            gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
            label = "Custom gpio 28";
        };
        gpiocus1: gpiocus_1 {
            gpios = <&gpio0 26 GPIO_ACTIVE_LOW>;
            label = "Custom gpio 29";
        };
    };
    aliases {
        gpiocus0 = &gpiocus0;
        gpiocus1 = &gpiocus1;
    };
};

My defines:

#define CUS_PIN0_NODE	DT_NODELABEL(gpiocus0)
#define CUS_PIN0		DT_GPIO_PIN(CUS_PIN0_NODE, gpios)

And the code in main()

	const struct device *dev_gpio0;

	dev_gpio0 = DEVICE_DT_GET(DT_NODELABEL(gpiocus0));
	if (!device_is_ready(dev_gpio0)) {
		printk("main: gpio not ready\n");
	}
	gpio_pin_configure(dev_gpio0, CUS_PIN0,  GPIO_OUTPUT);
	gpio_pin_set(dev_gpio0, CUS_PIN0, 0);

Resulting in this error:

C:\dev\myapp\src\main.c:296: undefined reference to `__device_dts_ord_19'

[Priyanka]

Hello,
I am sorry, but we are short staffed this week due to Public Holidays in Norway. We will be back on Monday 22nd and hope to be able to answer all incoming requests within a couple of days, depending on the backlog. I am sorry for the inconvenience.

Best regards,
Priyanka

[Priyanka]

Hi Garrett,

Were you able to get it working? Have you taken a look into the overlay guide that we have? Also, from the NCS v2.0.0 onwards, we have the pinctrl introduced, about which you can read more here.

-Priyanka

[garrettb]

Hi Priyanka,

no, I have not been able to get it working so far.

I don't understand why all the sample code in the "read more here" link is using the uart0 pins.

Is there no example to use just an ordinary pin - one that is not already assigned to a uart?

I am sure this will all make sense, once it makes sense, but for now it is impossible for me to understand.

For example, reading through the nRF5340DK spec, it seems to indicate that the following gpio, available at various connectors, are unassigned:

P2: P0.04..07, 25, 26
P3: P1.00, 01, 04..09
P4: P1.10..15, 27
P5: P1.13..15
P6: P0.02, 03, 07, 10
P24: P0.11, 12, 28..31

So how would I define/use, e.g. P0.04 as a digital output, and P0.05 as a digital input?

G

[Priyanka]

Hi Garrett,

What you wrote seems to be correct, but it would be great to know what the line 296 is in your main.c ?

Maybe there is some referencing problem.

I will also try to reproduce the error, in the meantime.

-Priyanka

[garrettb]

Hi Priyanka

The line is the closing curly brace for the main() routine.

void main(void)
{
  const struct device *dev_gpio0;

  // - start
  dev_gpio0 = DEVICE_DT_GET(DT_NODELABEL(gpiocus0));

  if (!device_is_ready(dev_gpio0)) {
    printk("main: gpio not ready\n");
  }

  gpio_pin_configure(dev_gpio0, CUS_PIN0,  GPIO_OUTPUT);
  gpio_pin_set(dev_gpio0, CUS_PIN0, 0);
  // - end

  :
  :

}

Essentially if I comment out the above code (between the -start and -end comments), the code builds successfully, so it obviously does not like/agree with this line:

  dev_gpio0 = DEVICE_DT_GET(DT_NODELABEL(gpiocus0));

As, any subsequent reference to dev_gpio0 results in a failed build.

[garrettb]

Some more information:

The code builds if I use device_get_binding() instead of DEVICE_DT_GET(DT_NODELABEL( )).

I don't know if I will be able to actually manipulate the output, but it does build...

	//dev_gpio0 = DEVICE_DT_GET(DT_NODELABEL(gpiocus0));
	dev_gpio0 = device_get_binding("Custom gpio 28");
	if (!device_is_ready(dev_gpio0)) {
		printk("main: gpio not ready\n");
	}
	gpio_pin_configure(dev_gpio0, CUS_PIN0,  GPIO_OUTPUT);
	gpio_pin_set(dev_gpio0, CUS_PIN0, 0);

[Priyanka]

That's interesting, because it's generally recommended to use DEVICE_DT_GET() instead of device_get_binding() . Please take a look here: https://docs.zephyrproject.org/latest/releases/release-notes-3.2.html#devicetree 

-Priyanka

[garrettb]

Hi

I am revisiting this, and I have yet to get this working.
And now the matter is becoming highly urgent.

I have read so many posts, documentation, tutorials, and am going around in circles.

I am obviously missing one simple piece of information... please help thanks.

So, I started again, from scratch...

I am using nRF Connect SDK 2.1.0
My board is the nRF52840 DK

Step 1
I create a new application, from nrf samples: peripheral uart
Pristine build --> success

Step 2
I add the following to the app.overlay file:

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

so now the entire overlay file is as follows:

/*
 * Copyright (c) 2022 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

/ {
	chosen {
		nordic,nus-uart = &uart0;
	};
};

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

Pristine build --> success

In main.c, I added the definition:

#define MODE_BUTTON DT_ALIAS(gpiocus0)

Pristine build --> success

In main(), I added:

const struct device *const my_dev = DEVICE_DT_GET(MODE_BUTTON);

Pristine build --> success

In main(), I added:

if (!device_is_ready(my_dev)) {
  /* Not ready, do not use */
  return;
}

Pristine build --> error

undefined reference to `__device_dts_ord_20'

When I look at zephyr_final.map, from the last successful build, it does not include any mention of `__device_dts_ord_20'

When I look at the zephyr.dts file - after the build fail, it does include the gpiocus0 alias, and the overlay info:

	gpiocustom {
		compatible = "gpio-keys";
		gpiocus0: gpiocus_0 {
			gpios = < &gpio0 0x1c 0x1 >;
			label = "Custom gpio 28";
		};
	};

Note: I get the same buil derror whether I use node label or alias definition:

#define MODE_BUTTON DT_ALIAS(gpiocus0)
#define MODE_BUTTON DT_NODELABEL(gpiocus0)

#define MODE_BUTTON DT_ALIAS(gpiocus0)
#define MODE_BUTTON DT_NODELABEL(gpiocus0)

[Priyanka]

Hi,

Where in main() did you add this

if (!device_is_ready(my_dev)) {
/* Not ready, do not use */
return;
}

I tried this and did not get any build errors.

Regards,

Priyanka

[garrettb]

Hi Priyanka

Near the start of main() - see code below - although I just tried to further down, just before the forever loop, with the same result - build fail.

void main(void)
{
	int blink_status = 0;
	int err = 0;
	const struct device *const my_dev = DEVICE_DT_GET(MODE_BUTTON);		// !io!

	configure_gpio();

	err = uart_init();
	if (err) {
		error();
	}

	if (!device_is_ready(my_dev)) {										// !io!
	  /* Not ready, do not use */
	  return;
	  //return -ENODEV;
	}

	if (IS_ENABLED(CONFIG_BT_NUS_SECURITY_ENABLED)) {
		err = bt_conn_auth_cb_register(&conn_auth_callbacks);
		if (err) {
			printk("Failed to register authorization callbacks.\n");
			return;
		}

		err = bt_conn_auth_info_cb_register(&conn_auth_info_callbacks);
		if (err) {
			printk("Failed to register authorization info callbacks.\n");
			return;
		}
	}

	err = bt_enable(NULL);
	if (err) {
		error();
	}

	LOG_INF("Bluetooth initialized");

	k_sem_give(&ble_init_ok);

	if (IS_ENABLED(CONFIG_SETTINGS)) {
		settings_load();
	}

	err = bt_nus_init(&nus_cb);
	if (err) {
		LOG_ERR("Failed to initialize UART service (err: %d)", err);
		return;
	}

	err = bt_le_adv_start(BT_LE_ADV_CONN, ad, ARRAY_SIZE(ad), sd,
			      ARRAY_SIZE(sd));
	if (err) {
		LOG_ERR("Advertising failed to start (err %d)", err);
		return;
	}

	
	//if (!device_is_ready(my_dev)) {										// !io!
	//  /* Not ready, do not use */
	//  return;
	//  //return -ENODEV;
	//}

	for (;;) {
		dk_set_led(RUN_STATUS_LED, (++blink_status) % 2);
		k_sleep(K_MSEC(RUN_LED_BLINK_INTERVAL));
	}
}

I can zip the project and send it to you, if that helps. Just tell me how I can send a zipped project.

Regards

Garrett