Practical Zephyr - Devicetree semantics (Part 4) | Interrupt

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Having covered the Devicetree basics in the previous article, we now add semantics to our Devicetree using so-called bindings: For each supported type, we’ll create a corresponding binding and look at the generated output to understand how it can be used with Zephyr’s Devicetree API.

This is a companion discussion topic for the original entry at https://interrupt.memfault.com/blog/practical_zephyr_dt_semantics
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Thanks for the article series, I’ve been finding it useful getting up to speed with Zephyr. Following this article, I did get a bit stuck in the naming section of the blog post, the grep for ‘foo’ in devicetre_generated.h at the end of the section didn’t produce any results for me.

I should be using the same version of Zephyr (2.4.0) at the end of the section. Doing a before and after comparison of the devicetre_generated.h files the only change I could see was the compatible name, and couldn’t see the property values added. Any suggestions on what I might be doing wrong, or how to debug this?

Also, there were a few parts of this section I was a bit unsure about

  • The instructions in the naming section start off specifying using the name custom as the vendor name, but mid-way through it seems like these instructions describe the files having used the vendor name dummy which doesn’t seem to have been mentioned before.
  • I wasn’t completely sure about what it means to have the generator script update devicetree_generated without compiling (e.g. “Without recompiling, we can check whether the generator script has added our properties to devicetree_generated.h”). I was running the following as done in previous examples:
west build --board nrf52840dk_nrf52840 --build-dir ../build -- \
  -DEXTRA_DTC_OVERLAY_FILE="dts/playground/props-basics.overlay"

If it’s possible to clear any of this up for me that would be great, but either way thanks for creating this blog series :slight_smile:

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Hi - sorry for the late reply. You’re completely right, the custom, vendor prefix should be mentioned consistently.

The same is true for the compilation. It is of course necessary to recompile since otherwise the output isn’t generated by the compiler.

I updated the article!