Re: [PATCH 1/6] dt-bindings: hwmon: sparx5: add LAN969x fan controller

[Conor Dooley <conor@kernel.org>]

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On Tue, Oct 13, 2026 at 07:08:34PM +0200, Robert Marko wrote:
> On Tue, Oct 13, 2026 at 6:30 PM Conor Dooley <conor@kernel.org> wrote:
> >
> > On Tue, Oct 13, 2026 at 02:56:25PM +0200, Robert Marko wrote:
> > > LAN969x integrates a PWM fan controller with a tachometer input in
> > > addition to the Sparx5-compatible temperature sensor. Add a LAN969x
> > > hardware-monitor compatible and describe the second register region.
> > >
> > > Describe the fan as a child node using a two-cell PWM specifier for the
> > > period and standard polarity flags. The child also carries the optional
> > > tachometer pulses-per-revolution and thermal cooling properties.
> > >
> > > Keep the existing microchip,lan9691-temp compatible for device tree ABI
> > > compatibility.
> > >
> > > Signed-off-by: Robert Marko <robert.marko@sartura.hr>
> > > ---
> > >  .../bindings/hwmon/microchip,sparx5-temp.yaml | 90 ++++++++++++++++++-
> > >  1 file changed, 87 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/hwmon/microchip,sparx5-temp.yaml b/Documentation/devicetree/bindings/hwmon/microchip,sparx5-temp.yaml
> > > index 611fcadb1e771..e91c2a3ccd3c9 100644
> > > --- a/Documentation/devicetree/bindings/hwmon/microchip,sparx5-temp.yaml
> > > +++ b/Documentation/devicetree/bindings/hwmon/microchip,sparx5-temp.yaml
> > > @@ -4,13 +4,15 @@
> > >  $id: http://devicetree.org/schemas/hwmon/microchip,sparx5-temp.yaml#
> > >  $schema: http://devicetree.org/meta-schemas/core.yaml#
> > >
> > > -title: Microchip Sparx5 Temperature Monitor
> > > +title: Microchip Sparx5 Hardware Monitor
> > >
> > >  maintainers:
> > >    - Lars Povlsen <lars.povlsen@microchip.com>
> > >
> > >  description: |
> > > -  Microchip Sparx5 embedded temperature monitor
> > > +  Microchip Sparx5 temperature monitor with a fan controller on LAN969x.
> > > +  The fan child's pwms property references this node to specify the
> > > +  PWM period and polarity.
> > >
> > >  properties:
> > >    compatible:
> > > @@ -18,11 +20,19 @@ properties:
> > >        - const: microchip,sparx5-temp
> > >        - items:
> > >            - enum:
> > > +              - microchip,lan9691-hwmon
> > >                - microchip,lan9691-temp
> > >            - const: microchip,sparx5-temp
> > >
> > >    reg:
> > > -    maxItems: 1
> > > +    minItems: 1
> > > +    maxItems: 2
> > > +
> > > +  reg-names:
> > > +    minItems: 1
> > > +    items:
> > > +      - const: temp
> > > +      - const: fan
> > >
> > >    clocks:
> > >      items:
> > > @@ -31,11 +41,67 @@ properties:
> > >    '#thermal-sensor-cells':
> > >      const: 0
> > >
> > > +  '#pwm-cells':
> > > +    const: 2
> > > +    description: |
> > > +      Number of cells in a PWM specifier.
> > > +      - cell 0: PWM period in nanoseconds
> > > +      - cell 1: PWM polarity: 0 or PWM_POLARITY_INVERTED
> > > +
> > > +  fan:
> > > +    $ref: fan-common.yaml#
> > > +    unevaluatedProperties: false
> > > +
> > > +    properties:
> > > +      cooling-levels:
> > > +        description:
> > > +          PWM duty-cycle values corresponding to thermal cooling states.
> > > +        items:
> > > +          maximum: 255
> > > +
> > > +      pulses-per-revolution:
> > > +        minimum: 1
> > > +        maximum: 4
> > > +        default: 2
> > > +
> > > +    required:
> > > +      - pwms
> > > +
> > > +    dependencies:
> > > +      '#cooling-cells':
> > > +        - cooling-levels
> > > +      cooling-levels:
> > > +        - '#cooling-cells'
> > > +
> > >  required:
> > >    - compatible
> > >    - reg
> > >    - clocks
> > >
> > > +allOf:
> > > +  - if:
> > > +      properties:
> > > +        compatible:
> > > +          contains:
> > > +            const: microchip,lan9691-hwmon
> > > +    then:
> > > +      properties:
> > > +        reg:
> > > +          minItems: 2
> > > +        reg-names:
> > > +          minItems: 2
> > > +      required:
> > > +        - '#pwm-cells'
> > > +        - reg-names
> > > +    else:
> > > +      properties:
> > > +        '#pwm-cells': false
> > > +        fan: false
> > > +        reg:
> > > +          maxItems: 1
> > > +        reg-names:
> > > +          maxItems: 1
> > > +
> > >  additionalProperties: false
> > >
> > >  examples:
> > > @@ -46,3 +112,21 @@ examples:
> > >          #thermal-sensor-cells = <0>;
> > >          clocks = <&sys_clk>;
> > >      };
> > > +
> > > +  - |
> > > +    #include <dt-bindings/pwm/pwm.h>
> > > +
> > > +    hwmon: hwmon@e2020100 {
> > > +        compatible = "microchip,lan9691-hwmon", "microchip,sparx5-temp";
> > > +        reg = <0xe2020100 0xc>, <0xe2010348 0xc>;
> >
> > Are these actually the same device? These are somewhat disparate
> > register regions - and the second is at a very odd offset.
> 
> Not really, they can be separately configured and have their own register space.
> 
> I did not see a point in separate drivers, but we could model these as
> separate DT
> nodes with their individual bindings if that is more appropriate.

Doing that seems more appropriate to me.

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