Re: [PATCH V15 2/4] dt-bindings: pwm: add IPQ6018 binding

[Kathiravan Thirumoorthy]

On 10/20/2023 8:44 PM, Rob Herring wrote:
> On Wed, Oct 18, 2023 at 3:46 PM Uwe Kleine-König
> <u.kleine-koenig@xxxxxxxxxxxxxx> wrote:
> > Hello,
> >
> > On Thu, Oct 05, 2023 at 09:35:48PM +0530, Devi Priya wrote:
> > > DT binding for the PWM block in Qualcomm IPQ6018 SoC.
> > >
> > > Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
> > > Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> > > Co-developed-by: Baruch Siach <baruch.siach@xxxxxxxxx>
> > > Signed-off-by: Baruch Siach <baruch.siach@xxxxxxxxx>
> > > Signed-off-by: Devi Priya <quic_devipriy@xxxxxxxxxxx>
> > > ---
> > > v15:
> > >
> > >    No change
> > >
> > > v14:
> > >
> > >    Picked up the R-b tag
> > >
> > > v13:
> > >
> > >    Updated the file name to match the compatible
> > >
> > >    Sorted the properties and updated the order in the required field
> > >
> > >    Dropped the syscon node from examples
> > >
> > > v12:
> > >
> > >    Picked up the R-b tag
> > >
> > > v11:
> > >
> > >    No change
> > >
> > > v10:
> > >
> > >    No change
> > >
> > > v9:
> > >
> > >    Add 'ranges' property to example (Rob)
> > >
> > >    Drop label in example (Rob)
> > >
> > > v8:
> > >
> > >    Add size cell to 'reg' (Rob)
> > >
> > > v7:
> > >
> > >    Use 'reg' instead of 'offset' (Rob)
> > >
> > >    Drop 'clock-names' and 'assigned-clock*' (Bjorn)
> > >
> > >    Use single cell address/size in example node (Bjorn)
> > >
> > >    Move '#pwm-cells' lower in example node (Bjorn)
> > >
> > >    List 'reg' as required
> > >
> > > v6:
> > >
> > >    Device node is child of TCSR; remove phandle (Rob Herring)
> > >
> > >    Add assigned-clocks/assigned-clock-rates (Uwe Kleine-König)
> > >
> > > v5: Use qcom,pwm-regs for phandle instead of direct regs (Bjorn
> > >      Andersson, Kathiravan T)
> > >
> > > v4: Update the binding example node as well (Rob Herring's bot)
> > >
> > > v3: s/qcom,pwm-ipq6018/qcom,ipq6018-pwm/ (Rob Herring)
> > >
> > > v2: Make #pwm-cells const (Rob Herring)
> > >
> > >   .../bindings/pwm/qcom,ipq6018-pwm.yaml        | 45 +++++++++++++++++++
> > >   1 file changed, 45 insertions(+)
> > >   create mode 100644 Documentation/devicetree/bindings/pwm/qcom,ipq6018-pwm.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/pwm/qcom,ipq6018-pwm.yaml b/Documentation/devicetree/bindings/pwm/qcom,ipq6018-pwm.yaml
> > > new file mode 100644
> > > index 000000000000..6d0d7ed271f7
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/pwm/qcom,ipq6018-pwm.yaml
> > > @@ -0,0 +1,45 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/pwm/qcom,ipq6018-pwm.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Qualcomm IPQ6018 PWM controller
> > > +
> > > +maintainers:
> > > +  - Baruch Siach <baruch@xxxxxxxxxx>
> > Not being very fluent in dt and binding yaml I wonder if adding
> >
> >          allOf:
> >            - $ref: pwm.yaml#
> >
> > would be beneficial?!
> Not really because the only thing you pick up is #pwm-cells, but
> that's still needed here since that varies by binding. A reference
> generally becomes useful when there are child nodes (e.g. a bus
> binding) or multiple properties.
>
> > > +properties:
> > > +  compatible:
> > > +    const: qcom,ipq6018-pwm
> > > +
> > > +  reg:
> > > +    description: Offset of PWM register in the TCSR block.
> > > +    maxItems: 1
> > > +
> > > +  clocks:
> > > +    maxItems: 1
> > > +
> > > +  "#pwm-cells":
> > > +    const: 2
> > The driver only supports normal polarity. Is this a shortcoming of the
> > driver, or is the hardware incapable to do that, too?
> >
> > If it's only the former I'd want #pwm-cells = <3> here. For ease of use
> > I'd not oppose if you pick #pwm-cells = <3> even if the hardware can
> > only do normal polarity.
> Devi, Can we get an answer here soon.


Rob, Devi is on vacation for couple of weeks. I don't have much idea on 
this as of now, how can I help here, if needed?


> The MFD part has been applied and it references this schema causing
> warnings. So this needs to land or MFD schema reverted.
>
> Rob