Re: [PATCH V3 1/3] dt-bindings: clk: sprd: Add bindings for ums512 clock controller

[Cixi Geng <gengcixi@gmail.com>]

Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org> 于2022年4月19日周二 00:28写道：
>
> On 18/04/2022 14:56, Cixi Geng wrote:
> > From: Cixi Geng <cixi.geng1@unisoc.com>
> >
> > Add a new bindings to describe ums512 clock compatible string.
> >
> > Signed-off-by: Cixi Geng <cixi.geng1@unisoc.com>
> > ---
> >  .../bindings/clock/sprd,ums512-clk.yaml       | 112 ++++++++++++++++++
> >  1 file changed, 112 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/clock/sprd,ums512-clk.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/clock/sprd,ums512-clk.yaml b/Documentation/devicetree/bindings/clock/sprd,ums512-clk.yaml
> > new file mode 100644
> > index 000000000000..89824d7c6be4
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/clock/sprd,ums512-clk.yaml
> > @@ -0,0 +1,112 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +# Copyright 2022 Unisoc Inc.
> > +%YAML 1.2
> > +---
> > +$id: "http://devicetree.org/schemas/clock/sprd,ums512-clk.yaml#"
> > +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> > +
> > +title: UMS512 Clock Control Unit Device Tree Bindings
>
> Remove "Device Tree Bindings". You could do the same also in the
> subject, because you repeat the prefix ("dt-bindings: clk: sprd: Add
> ums512 clock controller").
>
> > +
> > +maintainers:
> > +  - Orson Zhai <orsonzhai@gmail.com>
> > +  - Baolin Wang <baolin.wang7@gmail.com>
> > +  - Chunyan Zhang <zhang.lyra@gmail.com>
> > +
> > +properties:
> > +  "#clock-cells":
> > +    const: 1
> > +
> > +  compatible:
>
> Put the compatible first, by convention and makes finding matching
> bindings easier.
>
> > +    oneOf:
> > +      - items:
> > +          - const: sprd,ums512-glbregs
> > +          - const: syscon
> > +          - const: simple-mfd
>
> Why do you need simple-mfd for these? This looks like a regular syscon,
> so usually does not come with children. What is more, why this "usual
> syscon" is a separate clock controller in these bindings?
there is a warning log before add these const.  and the reason we need
the simply-mfd
is some clock is a child of syscon node,which should set these compatible.
failed to match any schema with compatible: ['sprd,ums512-glbregs',
'syscon', 'simple-mfd']
>
> > +      - items:
> > +          - enum:
> > +              - sprd,ums512-apahb-gate
> > +              - sprd,ums512-ap-clk
> > +              - sprd,ums512-aonapb-clk
> > +              - sprd,ums512-pmu-gate
> > +              - sprd,ums512-g0-pll
> > +              - sprd,ums512-g2-pll
> > +              - sprd,ums512-g3-pll
> > +              - sprd,ums512-gc-pll
> > +              - sprd,ums512-aon-gate
> > +              - sprd,ums512-audcpapb-gate
> > +              - sprd,ums512-audcpahb-gate
> > +              - sprd,ums512-gpu-clk
> > +              - sprd,ums512-mm-clk
> > +              - sprd,ums512-mm-gate-clk
> > +              - sprd,ums512-apapb-gate
> > +
> > +  clocks:
> > +    minItems: 1
>
> maxItems needed
the previous version did has the maxitems, but makes error when run
'make DT_CHECKER_FLAGS=-m dt_binding_check O=./dt-out  \
DT_SCHEMA_FILES=Documentation/devicetree/bindings/clock/sprd,ums512-clk.yaml'
  CHKDT   Documentation/devicetree/bindings/processed-schema.json
/path-to-linux/Documentation/devicetree/bindings/clock/sprd,ums512-clk.yaml:
properties:clock-names: {'minItems': 1, 'maxItems': 4, 'items':
[{'const': 'ext-26m'}, {'const': 'ext-32k'}, {'const': 'ext-4m'},
{'const': 'rco-100m'}]} should not be valid under {'required':
['maxItems']}
hint: "maxItems" is not needed with an "items" list

>
> > +    description: |
> > +      The input parent clock(s) phandle for this clock, only list fixed
> > +      clocks which are declared in devicetree.
>
> The description does not make sense. These are bindings for a clock
> controller, but you say here "for this clock", so what does "this" mean
> here?
>
> > +
> > +  clock-names:
> > +    minItems: 1
> > +    items:
> > +      - const: ext-26m
> > +      - const: ext-32k
> > +      - const: ext-4m
> > +      - const: rco-100m
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +required:
> > +  - compatible
> > +  - '#clock-cells'
>
> Isn't reg also required? Always? Do you have examples where it is not
> required? How do you configure the clocks without "reg"? I see you
> copied a lot from sprd,sc9863a-clk.yaml but that file does not look correct.
>
> You have nodes with reg but without unit address ("rpll"). These nodes
> are modeled as children but they are not children - it's a workaround
> for exposing syscon, isn't it? The sc9863a looks like broken design, so
> please do not duplicate it here.
>
> > +
> > +if:
> > +  properties:
> > +    compatible:
> > +      enum:
> > +        - sprd,ums512-ap-clk
> > +        - sprd,ums512-aonapb-clk
> > +        - sprd,ums512-mm-clk
> > +then:
> > +  required:
> > +    - reg
> > +
> > +else:
> > +  description: |
> > +    Other UMS512 clock nodes should be the child of a syscon node in
> > +    which compatible string should be:
> > +            "sprd,ums512-glbregs", "syscon", "simple-mfd"
> > +
> > +    The 'reg' property for the clock node is also required if there is a sub
> > +    range of registers for the clocks.
> > +
> > +additionalProperties: true
>
> false
the "false" makes error log:
/path-to-linux/Documentation/devicetree/bindings/clock/sprd,ums512-clk.example.dtb:
syscon@71000000: '#address-cells', '#size-cells',
'clock-controller@0', 'ranges' do not match any of the regexes:
'pinctrl-[0-9]+'
and I reference the patch
[https://www.spinics.net/lists/linux-leds/msg17032.html]

>
> > +
> > +examples:
> > +  - |
> > +    ap_clk: clock-controller@20200000 {
> > +      compatible = "sprd,ums512-ap-clk";
> > +      reg = <0x20200000 0x1000>;
> > +      clocks = <&ext_26m>;
> > +      clock-names = "ext-26m";
> > +      #clock-cells = <1>;
> > +    };
> > +
> > +  - |
> > +    ap_apb_regs: syscon@71000000 {
> > +      compatible = "sprd,ums512-glbregs", "syscon", "simple-mfd";
>
> So here is the answer why you added MFD, but I still don't get why do
> you need it for one child? It is quite a dance here and in your drivers,
> instead of adding "syscon" to your clock controller.

[1]in the if/else describtion,  th other UMS512 clock nodes should be
the child of a syscon node in
which compatible string should be:   "sprd,ums512-glbregs", "syscon",
"simple-mfd"

>
> This also pollutes the actual bindings because you did not add
> properties required for clock controllers, because of describing here
> the syscon part.
>
> > +      reg = <0x71000000 0x3000>;
> > +      #address-cells = <1>;
> > +      #size-cells = <1>;
> > +      #clock-cells = <1>;
> > +      ranges = <0 0x71000000 0x3000>;
> > +
> > +      apahb_gate: clock-controller@0 {
> > +        compatible = "sprd,ums512-apahb-gate";
> > +        reg = <0x0 0x2000>;
> > +        #clock-cells = <1>;
> > +      };
> > +    };
> > +
> > +...
>
>
> Best regards,
> Krzysztof