Zephyr device tree label not working correctly

[Alexander Lopatin]

Hello everyone,

I'm currently working on porting a device driver to Zephyr on the nRF9160.  I have defined a device tree and set up the device through the .overlay file. As soon as I try to call device_get_binding("WFM200") Zephyr crashes and stays in a boot loop. Everything is working correctly if I call device_get_binding("SPI_2"). I have built the device tree by looking at examples but I suspect that I'm missing something.

Help would be greatly appreciated.

Thanks in advance!

silabs,wfx.yaml:

description: SiLabs WFX module

compatible: "silabs,wfx"

include: spi-device.yaml

properties:
    cs-gpios:
      type: phandle-array
      required: true
      
    resetn-gpios:
      type: phandle-array
      required: true

    irq-gpios:
      type: phandle-array
      required: true

    wakeup-gpios:
      type: phandle-array
      required: false

nrf9160dk_nrf9160ns.overlay:

&spi2 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	sck-pin = <10>;
	mosi-pin = <11>;
	miso-pin = <12>;

	wfx@0 {
		status = "okay";
		compatible = "silabs,wfx";
		label = "WFM200";
		reg = <0x0>;

		spi-max-frequency = <8000000>;

		cs-gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
		resetn-gpios = <&gpio0 25 GPIO_ACTIVE_LOW>;
		irq-gpios = <&gpio0 17 GPIO_ACTIVE_HIGH>;
		wakeup-gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
	};
};

[Simon]

It is not enough to define the WFM200 in the device tree in order to call device_get_binding(). You need to add the device using e.g. DEVICE_DT_DEFINE(), such that it can be seen by the Device Driver Model. You can also use the macros in include/devicetree/spi.h to get the values of fields set in the overlay file, then use that values to configure the WFM200, like done for the adxl362: https://github.com/nrfconnect/sdk-zephyr/blob/master/drivers/sensor/adxl362/adxl362.c#L800-L814. Remember to set DT_DRV_COMPAT at the top of the driver, for your case I think it should be set equal to silabs_wfx. 

Best regards,

Simon

[Alexander Lopatin]

Hello Simon, thanks for the quick answer. Unfortunately I was not able to get it working using DEVICE_DT_INST_DEFINE. I was getting an error: "expected declaration specifiers or ‘...’ before ‘(’ token". Looking at other drivers made for WiFi expansion boards (i.e. eswifi) NET_DEVICE_OFFLOAD_INIT seems to be the right call for my needs. I will report back if this worked.

[Simon]

This little guide may be useful: https://devzone.nordicsemi.com/f/nordic-q-a/66230/how-to-add-new-i2c-based-sensor-device-to-ncs-v1-3-0-zephyr-drivers-sensor/271109#271109 

[Alexander Lopatin]

Sorry for the delayed answer. It has worked. The WFM200 is being initialized correctly and I can make the calls I need. NET_DEVICE_... calls will initialize the device from the device tree and directly integrate the chip into Zephyrs network stack, given the correct functions have been written according to the API.

[Simon]

I'm hapy you got it to work