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From:   Peter Geis <pgwipeout@gmail.com>
Date:   Fri, 25 Feb 2022 13:04:10 -0500
Message-ID: <CAMdYzYo81L5YnLr=whBbqde--e_DSuSwSPaXuDwtzeXN7pLMwQ@mail.gmail.com>
Subject: Re: [PATCH v1 2/8] dt-bindings: usb: dwc3: add description for rk3568
To:     Johan Jonker <jbx6244@gmail.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        Heiko Stuebner <heiko@sntech.de>, linux-usb@vger.kernel.org,
        devicetree <devicetree@vger.kernel.org>,
        arm-mail-list <linux-arm-kernel@lists.infradead.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Michael Riesch <michael.riesch@wolfvision.net>
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On Fri, Feb 25, 2022 at 11:07 AM Johan Jonker <jbx6244@gmail.com> wrote:
>
> Hi Peter,
>
> Lots of USB series all of a sudden.
> Combine possible?
>
> On 2/25/22 15:54, Peter Geis wrote:
> > The rk3568 dwc3 controllers are backwards compatible with the rk3399.
> > Add the device tree description for it.
> >
> > Signed-off-by: Peter Geis <pgwipeout@gmail.com>
> > ---
> >  Documentation/devicetree/bindings/usb/rockchip,dwc3.yaml | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/devicetree/bindings/usb/rockchip,dwc3.yaml b/Documentation/devicetree/bindings/usb/rockchip,dwc3.yaml
> > index 04077f2d7faf..e3044e81cc72 100644
> > --- a/Documentation/devicetree/bindings/usb/rockchip,dwc3.yaml
> > +++ b/Documentation/devicetree/bindings/usb/rockchip,dwc3.yaml
> > @@ -30,6 +30,7 @@ select:
> >          enum:
> >            - rockchip,rk3328-dwc3
> >            - rockchip,rk3399-dwc3
> > +          - rockchip,rk3568-dwc3
> >    required:
> >      - compatible
> >
> > @@ -39,6 +40,7 @@ properties:
> >        - enum:
> >            - rockchip,rk3328-dwc3
> >            - rockchip,rk3399-dwc3
> > +          - rockchip,rk3568-dwc3
> >        - const: snps,dwc3
> >
> >    reg:
> > @@ -75,7 +77,10 @@ properties:
> >      maxItems: 1
> >
> he
> >    reset-names:
> > -    const: usb3-otg
> > +    items:
> > +      - enum:
> > +          - usb3-otg
> > +          - usb3-host
>
> The use of reset-names is "sort of" only related to the rk3399 legacy
> node. Still using this sub node DT to not to break older existing boot
> loaders.
>
> https://github.com/torvalds/linux/search?q=usb3-otg
>
> It's only mentioned as comment in dwc3-of-simple.c but not used:
>
>         simple->resets = of_reset_control_array_get(np, false, true,
>                                                     true);
> core.c uses something similar.
>
>         dwc->reset = devm_reset_control_array_get_optional_shared(dev);
>         if (IS_ERR(dwc->reset))
>                 return PTR_ERR(dwc->reset);
>
>
> Up to the maintainers, but I wouldn't add another variant/name for the
> same thing as it also optional(= not required) and no longer needed.

I left these named separately since they are different reset signals,
but if it isn't an issue I don't mind having them both be usb3-otg.

>
> Johan
>
> ===
>
> Maybe drop PCLK_PIPE as well to reduce notifications.

I'll be conducting testing to determine if we need PCLK_PIPE here, and
as long as it isn't working simply because it's enabled by someone
else I'll drop it.
Ideally, it would be nice to have a proper clock map for these chips,
but currently that's not in the TRM.

>
> See example:
> https://lore.kernel.org/linux-rockchip/20220225131602.2283499-4-michael.riesch@wolfvision.net/T/#u
>
> >
> >  unevaluatedProperties: false
> >

Thanks for the review!