Re: [PATCH 1/2] dt-bindings: usb: snps,dwc3: Allow power-domains property

From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
To: Felipe Balbi <balbi@kernel.org>
Cc: Rob Herring <robh@kernel.org>, Heiko Stuebner <heiko@sntech.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
	"linux-rockchip@lists.infradead.org"
	<linux-rockchip@lists.infradead.org>,
	Johan Jonker <jbx6244@gmail.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] dt-bindings: usb: snps,dwc3: Allow power-domains property
Date: Fri, 23 Dec 2022 23:57:15 +0000	[thread overview]
Message-ID: <20221223235712.h54lggnjjuu3weol@synopsys.com> (raw)
In-Reply-To: <878riy9ztm.fsf@balbi.sh>

Hi,

On Fri, Dec 23, 2022, Felipe Balbi wrote:
> 
> Hi,
> 
> Rob Herring <robh@kernel.org> writes:
> >> > The Rockchip RK3399 DWC3 node has 'power-domain' property which isn't
> >> > allowed by the schema:
> >> >
> >> > usb@fe900000: Unevaluated properties are not allowed ('power-domains' was unexpected)
> >> >
> >> > Allow DWC3 nodes to have a single power-domains entry. We could instead
> >> > move the power-domains property to the parent wrapper node, but the
> >> > could be an ABI break (Linux shouldn't care). Also, we don't want to
> >> > encourage the pattern of wrapper nodes just to define resources such as
> >> > clocks, resets, power-domains, etc. when not necessary.
> >> >
> >> > Signed-off-by: Rob Herring <robh@kernel.org>
> >> > ---
> >> >  Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 3 +++
> >> >  1 file changed, 3 insertions(+)
> >> >
> >> > diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> >> > index 6d78048c4613..bcefd1c2410a 100644
> >> > --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> >> > +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> >> > @@ -91,6 +91,9 @@ properties:
> >> >          - usb2-phy
> >> >          - usb3-phy
> >> >
> >> > +  power-domains:
> >> > +    maxItems: 1
> >>
> >> AFAICT this can be incorrect. Also, you could have Cc the dwc3
> >> maintainer to get comments.

Felipe is correct. We have 2 power-domains: Core domain and PMU.

> >
> > When we have a user with more and know what each one is, then we can
> > extend it. All the other users (upstream), put 'power-domains' in the
> 
> Won't that be an ABI break at that point? You'll change the maximum
> number of power-domains.
> 
> > wrapper node. But this is what we need now for RK3399.
> >
> > I used get_maintainers.pl. If that's the wrong output, fix it please.
> 
> @Thinh, perhaps you should add dwc3 binding file to the list of
> maintained files for you?
> 

Sure, if makes sense to do so. If there's no objection, I can also
maintain/review it.

I can create a patch after coming back from my break in 2 weeks.
Since I'm on a break at the moment, my response may be delayed.

Thanks,
Thinh
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