Re: [PATCH v1 3/3] samples: rust: platform: Add property child and reference args examples

[Danilo Krummrich <dakr@kernel.org>]

On Tue, Jun 17, 2025 at 08:01:08AM -0500, Rob Herring wrote:
> On Mon, Jun 16, 2025 at 10:45 AM Remo Senekowitsch <remo@buenzli.dev> wrote:
> > @@ -91,6 +95,13 @@ fn properties_parse(dev: &device::Device) -> Result {
> >          let prop: KVec<i16> = fwnode.property_read_array_vec(name, 4)?.required_by(dev)?;
> >          dev_info!(dev, "'{name}'='{prop:?}' (KVec)\n");
> >
> > +        for child in fwnode.children() {
> > +            let name = c_str!("test,ref-arg");
> > +            let nargs = NArgs::N(2);
> > +            let prop: FwNodeReferenceArgs = child.property_get_reference_args(name, nargs, 0)?;
> 
> Is there some reason we can just pass 2 in rather than nargs? Seems
> overly verbose for my tastes.

It's because you could also pass NArgs::Prop("foo-bar") to indicate the the
name of the property telling the number of arguments.

NArgs is defined as

	pub enum NArgs<'a> {
	    /// The name of the property of the reference indicating the number of
	    /// arguments.
	    Prop(&'a CStr),
	    /// The known number of arguments.
	    N(u32),
	}

and FwNode::property_get_reference_args() can match against the corresponding
enum variant to cover both cases.

> > +            dev_info!(dev, "'{name}'='{prop:?}'\n");
> > +        }
> > +
> >          Ok(())
> >      }
> >  }
> > --
> > 2.49.0
> >