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Subject: Re:Re: [PATCH v4 2/4] dt-bindings: mfd: sprd: Add bindings for ums512 global registers
From:   Stephen Boyd <sboyd@kernel.org>
Cc:     Chunyan Zhang <zhang.lyra@gmail.com>,
        Rob Herring <robh+dt@kernel.org>, linux-clk@vger.kernel.org,
        devicetree@vger.kernel.org, Baolin Wang <baolin.wang7@gmail.com>,
        Orson Zhai <orsonzhai@gmail.com>,
        Chunyan Zhang <chunyan.zhang@unisoc.com>,
        LKML <linux-kernel@vger.kernel.org>
To:     ChunyanZhang <zhanglyra@163.com>
Date:   Wed, 13 Oct 2021 18:51:25 -0700
Message-ID: <163417628586.936110.17321921086246870791@swboyd.mtv.corp.google.com>
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Quoting ChunyanZhang (2021-10-13 16:49:40)
> At 2021-10-14 06:04:32, "Stephen Boyd" <sboyd@kernel.org> wrote:
> >Quoting Chunyan Zhang (2021-09-22 23:41:35)
> >> diff --git a/Documentation/devicetree/bindings/mfd/sprd,ums512-glbreg.=
yaml b/Documentation/devicetree/bindings/mfd/sprd,ums512-glbreg.yaml
> >> +
> >> +examples:
> >> +  - |
> >> +    ap_apb_regs: syscon@71000000 {
> >> +      compatible =3D "sprd,ums512-glbregs", "syscon", "simple-mfd";
> >> +      reg =3D <0x71000000 0x3000>;
> >> +      #address-cells =3D <1>;
> >> +      #size-cells =3D <1>;
> >> +      ranges =3D <0 0x71000000 0x3000>;
> >> +
> >> +      clock-controller@0 {
> >> +        compatible =3D "sprd,ums512-apahb-gate";
> >
> >Why is this a subnode of a syscon and simple-mfd? Why not put the>clock-=
controller@71000000 directly onto the bus? Does making it a child
> >node help somehow?
>=20
> These clocks are at the same register range with global registers. I orig=
inally put them directly onto the bus indeed when submitting the patches fo=
r SC9863A clocks last year, and it had a private property named 'sprd,sysco=
n' which could provide regmap for these clocks.
>=20
> Rob suggested [1] us to make them a child of the syscon, and would not ne=
ed the private property 'sprd, syscon' then.

Why do you need to use a syscon? Are the registers shared with some
other driver?

2019 was two years ago...