tests: drivers: gpio: gpio_basic_api: correct dts binding

[cfriedt]

Is your enhancement proposal related to a problem? Please describe.
As @sjg20 pointed out in #26484, compatible strings should use '-' instead of '_'.

Describe the solution you'd like
The existing "test,gpio_basic_api" binding should be changed to "test,gpio-basic-api". All of the boards / relevant files in tests/drivers/gpio/gpio_basic_api should be corrected to reflect that change.

Describe alternatives you've considered

Additional context

[pabigot]

While it's true that the vast majority of compatible strings use - as separators the devicetree specification does not mandate or even mention this, and there is existing practice in Zephyr and in Linux for using _ as a separator, particularly but not exclusively when there is no vendor, prefix.

I don't object to making this change if we agree and document that's a standard we should follow, and add checks to the tooling to warn when people violate it. @sjg20 @mbolivar @galak

[pabigot]

BTW: I believe the reason I went with test,gpio_basic_api originally is because this is the binding used for the gpio_basic_api test (not the gpio-basic-api test). I'm still a little bit inclined to allowing that as an exception, especially since it's essentially a private binding.

[galak]

I don't object to making this change if we agree and document that's a standard we should follow, and add checks to the tooling to warn when people violate it. @sjg20 @mbolivar @galak

While it seems general convention to use - instead of _ there isn't anything in the DTS specs around conventions for compatible beyond vendor, prefix usage. So if someone wants to propose that as a change to the DTS spec than I'm all for adding a warning in the tooling if it is accepted (https://github.com/devicetree-org/devicetree-specification).

[sjg20]

Certainly this is a pretty strong convention. The DT spec examples all use hyphen and the the /aliases node requires it, but oddly it has capital letters for the alias labels.

This convention is a bit confusing in Zephyr because hyphen gets converted to underscore to become a valid C identifier

The underscore is reserved for phandle names.

[sjg20]

@cfriedt I'm happy to have a crack at a DT spec update if you don't want to do it.

[cfriedt]

@cfriedt I'm happy to have a crack at a DT spec update if you don't want to do it.

I think it's unrelated to the other PR for the most part, so please go ahead.

[sjg20]

Applied here:
devicetree-org/devicetree-specification#42