Re: dt_binding_check report false alarm?

[Conor Dooley <conor@kernel.org>]

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On Thu, May 25, 2023 at 10:10:46AM -0700, William Zhang wrote:
> 
> 
> On 05/25/2023 08:33 AM, Conor Dooley wrote:
> > On Thu, May 25, 2023 at 08:23:30AM -0700, William Zhang wrote:
> > > Sorry for the multiple emails. Our mail relay server was not working
> > > properly.
> > 
> > I only got one /shrug
> > 
> That's good.  Maybe it only flushed queued email to internal email accounts.
> 
> > > On 05/25/2023 06:23 AM, Conor Dooley wrote:
> > > > Hey William,
> > > > 
> > > > On Wed, May 24, 2023 at 10:02:41PM -0700, William Zhang wrote:
> > > > > Hi,
> > > > > 
> > > > > It seems dt_binding_check reports a false error when run on this
> > > > > modified yaml. I picked this simple file just to demostrate this issue.
> > > > > Basically I made the interrupts and interrupt-names as optional
> > > > > properties. But when there are two interrupts present, then
> > > > > interrupt-names are required.  However in the example, I don't define
> > > > > interrupts and interrupt-name at all, the dt binding check reports error
> > > > > that interrupt-names are required:
> > > > 
> > > > Rob and Krzysztof would know more than me, but since they're not
> > > > around...
> > > > 
> > > > > diff --git a/Documentation/devicetree/bindings/crypto/fsl-imx-scc.yaml b/Documentation/devicetree/bindings/crypto/fsl-imx-scc.yaml
> > > > > index 563a31605d2b..c37a3a64a78c 100644
> > > > > --- a/Documentation/devicetree/bindings/crypto/fsl-imx-scc.yaml
> > > > > +++ b/Documentation/devicetree/bindings/crypto/fsl-imx-scc.yaml
> > > > > @@ -32,11 +32,18 @@ properties:
> > > > >      clock-names:
> > > > >        const: ipg
> > > > > +allOf:
> > > > > +  - if:
> > > > > +      properties:
> > > > > +        interrupts:
> > > > > +          minItems: 2
> > > > 
> > > > ...I don't think you can actually do this and "minItems: 2" will always
> > > > evaluate to true because it is an assignment. Don't hold me to that
> > > > though! The standard pattern here is to do:
> > > > allOf:
> > > >     - if:
> > > >         properties:
> > > >           compatible:
> > > >             contains:
> > > >               const: foo
> > > >       then:
> > > >         required:
> > > >           - interrupt-names

> > > Our device can use one or two interrupt, or choose to not use interrupt at
> > > all(polling mode). Interrupt names is only required when there are two
> > > interrupts(so the driver code can tell which is which).  So I will need to
> > > check if it contains two interrupts. My check does work if I have two
> > > interrupt but don't have interrupt name, the check catches the error.  If I
> > > have one interrupt without interrupt name, the check pass. Only when I does
> > > not have interrupt and interrupt name,  it falsely report error.  Looks to
> > > me that it does not treat minItem = 0 case properly.
> > 
> > Right. I would not bother with the "only interrupt-names when 2
> > interrupts" stuff & do the simple thing of always making it required
> > when you have interrupts.
> > Then you can use allOf and oneOf to allow for both schemes for the new
> > device and keep enforcement of 2 items for the existing one.

> I agree it is better to keep it simple. Sorry I am still new to yaml but
> what is the best way to check if interrupt property exist?  What I can think
> of is similar
> 
>  - if:
>       properties:
>         interrupts:
>           minItems: 1
>     then:
>       required:
>         - interrupt-names
> 
> But this still reports the same error when there is no interrupt.

Yeah, you don't need to do something like that.
It's hard to say exactly without your actual patch, but I think you're
over complicating things :)
What you seem to want to do (from where I am sitting) is something like:
	dependencies:
	  interrupts: interrupt-names

and not put interrupts/interrupt-names in the required bit.
That way, if you have interrupts, you need to have interrupt-names too
but you can have neither.

But yeah, without something resembling the "real" patch, rather than
hacking at the fsl one, it is kinda hard to say.

Cheers,
Conor.


> 
> > > > > +    then:
> > > > > +      required:
> > > > > +        - interrupt-names
> > > > > +
> > > > >    required:
> > > > >      - compatible
> > > > >      - reg
> > > > > -  - interrupts
> > > > > -  - interrupt-names
> > > > >      - clocks
> > > > >      - clock-names
> > > > > @@ -49,6 +56,4 @@ examples:
> > > > >            reg = <0x53fac000 0x4000>;
> > > > >            clocks = <&clks 111>;
> > > > >            clock-names = "ipg";
> > > > > -        interrupts = <49>, <50>;
> > > > > -        interrupt-names = "scm", "smn";
> > > > >        };
> > > > > -- 
> > > > > 2.34.1
> > > > > 
> > > > 
> > > > 
> > 
> > 



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