How to use SPI_DT_SPEC_GET?

[KenthJohan]

How to use SPI_DT_SPEC_GET?
https://docs.zephyrproject.org/latest/reference/peripherals/spi.html?highlight=spi_dt_spec#c.SPI_DT_SPEC_GET
https://docs.zephyrproject.org/latest/reference/peripherals/spi.html?highlight=spi_dt_spec#c.SPI_DT_SPEC_INST_GET

I cant find examples.
I'm testing on nucleo_wb55rg.

I added this overlay so a cs-gpio pin is defined:
boards/nucleo_wb55rg.overlay

&spi1 {
	pinctrl-0 = <&spi1_nss_pa4 &spi1_sck_pa5
		     &spi1_miso_pa6 &spi1_mosi_pa7>;
	pinctrl-names = "default";
	status = "okay";
	cs-gpios = <&gpioa 4 GPIO_ACTIVE_LOW>;
};

I'm not sure why SPI_DT_SPEC_GET doesn't work because what I have done is expend it manually with code.
main.c

struct spi_dt_spec spi_spec = 
{
	.bus = DEVICE_DT_GET(DT_NODELABEL(spi1)),
	.config = 
	{
		.operation = SPI_WORD_SET(8) | SPI_MODE_GET(0),
		.frequency = 1*1000*1000,
		.cs = &(struct spi_cs_control) 
		{
			.gpio_dev = DEVICE_DT_GET(DT_NODELABEL(gpioa)),
			.delay = 1,
			.gpio_pin = 4,
			.gpio_dt_flags = GPIO_ACTIVE_LOW
		}
	}
};

This works well but I would like to replace that with this shortcut so it depends more on the overlay file:

struct spi_dt_spec spi_spec1 = SPI_DT_SPEC_GET(DT_NODELABEL(spi1), SPI_WORD_SET(8) | SPI_MODE_GET(0), 1);

but that results in:
identifier "__device_dts_ord_DT_N_S_soc_S_spi_40013000_BUS_ORD" is undefined
I have this in devicetree_unfixed.h but there is no BUS word there.

#define DT_N_S_soc_S_spi_40013000_ORD 63

[erwango]

SPI_DT_SPEC_GET should actually be applied to a SPI device (sensor, ...) and not a SPI bus (spi1 in your case):

Cf:

 * @param node_id Devicetree node identifier for the SPI device whose
 *                struct spi_dt_spec to create an initializer for
 * @param operation_ the desired @p operation field in the struct spi_config
 * @param delay_ the desired @p delay field in the struct spi_config's
 *               spi_cs_control, if there is one
 */
#define SPI_DT_SPEC_GET(node_id, operation_, delay_)		     \

To use this macro, you should add such device in your dts description.

[erwango]

As previously mentioned, I suggest not using DT INST version, unless you know what you're doing.

Here, you're not defining correctly DT_DRV_COMPAT , you should define, in your case:
#define DT_DRV_COMPAT zephyr_spi

[KenthJohan]

Ok now it makes more sense. compatible value is the real identifier.
I stumbled on another error after fixing the first error.
error: 'DT_N_S_soc_S_spi_40013000_S_foo_0_P_spi_max_frequency' undeclared here
Which is strange because spi-max-frequency is defined in the overlay file.

&spi1 {
	status = "okay";
	pinctrl-0 = <&spi1_nss_pa4 &spi1_sck_pa5 &spi1_miso_pa6 &spi1_mosi_pa7>;
	pinctrl-names = "default";
	cs-gpios = <&gpioa 4 GPIO_ACTIVE_LOW>;
	foo: foo@0 {
		compatible = "zephyr,foo";
		reg = <0>;
		spi-max-frequency = <2000000>;
		label = "foo";
	};
};

main.c

#include <drivers/gpio.h>
#include <drivers/spi.h>
#include <drivers/pinctrl.h>
#include <zephyr.h>
#include <device.h>
#include <devicetree.h>

struct spi_dt_spec spec = SPI_DT_SPEC_GET(DT_NODELABEL(foo), SPI_WORD_SET(8) | SPI_MODE_GET(0), 1);
// error: 'DT_N_S_soc_S_spi_40013000_S_foo_0_P_spi_max_frequency' undeclared here

void main(void)
{
	while (1)
	{
		k_sleep(K_MSEC(1000));
	}
}

[erwango]

Ok, issue is that "zephyr,foo" was not defined as a valid compatible.
So, you need to populate a matching binding, for instance: dts/bindings/sensor/zephyr,foo.yaml
with:

description: My spi device binding

compatible: "zephyr,foo"

include: spi-device.yaml

[KenthJohan]

Yeah that works. Thanks.
I'm not sure if this is the correct way to use overlay files.
I want the SPI pins and CS-GPIO pins to be configurable so it can work on multiple boards.
So do we need a custom zephyr repo with a dts/bindings/sensor/zephyr,foo.yaml file or is there any better way to do this?

[erwango]

If you're wanting to build your own project on top of zephyr repo, adding your own bindings and so on, I'd suggest looking at https://github.com/zephyrproject-rtos/example-application which is provided for that purpose.