Re: [PATCH v5 1/3] dt-bindings: pwm: Add binding for Allwinner D1/T113-S3/R329 PWM controller

[Andre Przywara]

Hi,

On 23/08/2023 07:57, Александр Шубин wrote:
> Hi Andre,
>
> вт, 22 авг. 2023 г. в 12:49, Andre Przywara <andre.przywara@xxxxxxx>:
> > On Mon, 14 Aug 2023 16:32:16 +0300
> > Aleksandr Shubin <privatesub2@xxxxxxxxx> wrote:
> >
> > Hi Aleksandr,
> >
> > > Allwinner's D1, T113-S3 and R329 SoCs have a new pwm
> > > controller witch is different from the previous pwm-sun4i.
> > >
> > > The D1 and T113 are identical in terms of peripherals,
> > > they differ only in the architecture of the CPU core, and
> > > even share the majority of their DT. Because of that,
> > > using the same compatible makes sense.
> > > The R329 is a different SoC though, and should have
> > > a different compatible string added, especially as there
> > > is a difference in the number of channels.
> > >
> > > D1 and T113s SoCs have one PWM controller with 8 channels.
> > > R329 SoC has two PWM controllers in both power domains, one of
> > > them has 9 channels (CPUX one) and the other has 6 (CPUS one).
> > >
> > > Add a device tree binding for them.
> > >
> > > Signed-off-by: Aleksandr Shubin <privatesub2@xxxxxxxxx>
> > > ---
> > >   .../bindings/pwm/allwinner,sun20i-pwm.yaml    | 85 +++++++++++++++++++
> > >   1 file changed, 85 insertions(+)
> > >   create mode 100644 Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml b/Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml
> > > new file mode 100644
> > > index 000000000000..9512d4bed322
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/pwm/allwinner,sun20i-pwm.yaml
> > > @@ -0,0 +1,85 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/pwm/allwinner,sun20i-pwm.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Allwinner D1, T113-S3 and R329 PWM
> > > +
> > > +maintainers:
> > > +  - Aleksandr Shubin <privatesub2@xxxxxxxxx>
> > > +
> > > +properties:
> > > +  compatible:
> > > +    oneOf:
> > > +      - const: allwinner,sun20i-d1-pwm
> > > +      - items:
> > > +          - const: allwinner,sun20i-r329-pwm
> > > +          - const: allwinner,sun20i-d1-pwm
> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  "#pwm-cells":
> > > +    const: 3
> > > +
> > > +  clocks:
> > > +    items:
> > > +      - description: 24 MHz oscillator
> > > +      - description: Bus Clock
> >
> > The manual tells me that the new PWMs can also use APB0 as the
> > input clock, which (finally!) allows PWM frequencies above 24 MHz.
> > So we should have an explicit reference to that clock - even if the bus
> > clock happens to be gated version of APB0.
>
> Should I change it to something like this:
>      pwm: pwm@2000c00 {
>        compatible = "allwinner,sun20i-d1-pwm";
>        reg = <0x02000c00 0x400>;
>        clocks = <&ccu CLK_BUS_PWM>, <&dcxo>, <&ccu CLK_APB0>;
>        clock-names = "bus", "hosc", "apb0";
>        resets = <&ccu RST_BUS_PWM>;
>        #pwm-cells = <0x3>;
>      };

Yes, that is what I had in mind!
It shouldn't be too hard to add support for this in the driver as well.

Thanks!
Andre

> > Cheers,
> > Andre
> >
> > > +
> > > +  clock-names:
> > > +    items:
> > > +      - const: hosc
> > > +      - const: bus
> > > +
> > > +  resets:
> > > +    maxItems: 1
> > > +
> > > +  allwinner,pwm-channels:
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +    description: The number of PWM channels configured for this instance
> > > +    enum: [6, 9]
> > > +
> > > +allOf:
> > > +  - $ref: pwm.yaml#
> > > +
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            const: allwinner,sun20i-r329-pwm
> > > +
> > > +    then:
> > > +      required:
> > > +        - allwinner,pwm-channels
> > > +
> > > +    else:
> > > +      properties:
> > > +        allwinner,pwm-channels: false
> > > +
> > > +unevaluatedProperties: false
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - "#pwm-cells"
> > > +  - clocks
> > > +  - clock-names
> > > +  - resets
> > > +
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/clock/sun20i-d1-ccu.h>
> > > +    #include <dt-bindings/reset/sun20i-d1-ccu.h>
> > > +
> > > +    pwm: pwm@2000c00 {
> > > +      compatible = "allwinner,sun20i-d1-pwm";
> > > +      reg = <0x02000c00 0x400>;
> > > +      clocks = <&dcxo>, <&ccu CLK_BUS_PWM>;
> > > +      clock-names = "hosc", "bus";
> > > +      resets = <&ccu RST_BUS_PWM>;
> > > +      #pwm-cells = <0x3>;
> > > +    };
> > > +
> > > +...
>
> Cheers,
> Aleksandr