Re: [PATCH v3 1/5] dt-bindings: rtc: Add pinctrl for S35390A

[Markus Probst <markus.probst@posteo.de>]

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On Tue, 2026-08-11 at 21:08 -0500, Rob Herring wrote:
> On Wed, Aug 05, 2026 at 07:32:27PM +0000, Markus Probst wrote:
> > Synology NAS devices use the output pin for interrupt signal 1 to wake up
> > the system.
> > 
> > Move devicetree bindings for sii,s35390a into its own file.
> > Add necessary properties to configure the individual pins via pinctrl,
> > which allows the interrupt signal 1 to be used for wakeup alarm.
> > 
> > Signed-off-by: Markus Probst <markus.probst@posteo.de>
> > ---
> >  .../devicetree/bindings/rtc/sii,s35390a.yaml       | 109 +++++++++++++++++++++
> >  .../devicetree/bindings/rtc/trivial-rtc.yaml       |   3 -
> >  MAINTAINERS                                        |   1 +
> >  3 files changed, 110 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/rtc/sii,s35390a.yaml b/Documentation/devicetree/bindings/rtc/sii,s35390a.yaml
> > new file mode 100644
> > index 000000000000..0355f17f233a
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/rtc/sii,s35390a.yaml
> > @@ -0,0 +1,109 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/rtc/sii,s35390a.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: S-35390A 2-WIRE REAL-TIME CLOCK
> > +
> > +maintainers:
> > +  - Alexandre Belloni <alexandre.belloni@bootlin.com>
> 
> This should be someone with the h/w, not subsystem maintainer.
There has been a discussion about this before.
See
https://lore.kernel.org/all/20260701-bronze-jaguar-of-perfection-028bac@quoll/
and replies.

If desired I can use my own name.

> 
> > +
> > +description:
> > +  The S-35390A is a CMOS 2-wire real-time clock IC which operates with the
> > +  very low current consumption in the wide range of operation voltage.
> > +
> > +allOf:
> > +  - $ref: rtc.yaml#
> > +
> > +properties:
> > +  compatible:
> > +    const: sii,s35390a
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    minItems: 1
> > +    maxItems: 2
> > +    description: Supports up to 2 interrupt lines via the INT1 and INT2 pins.
> > +
> > +  wakeup-parent: true
> > +
> > +  wakeup-source: true
> > +
> > +  "#clock-cells":
> > +    const: 1
> > +
> > +patternProperties:
> > +  "^pins":
> 
> Do you need wild cards here? Wouldn't just 'pins' for the node name be 
> fine?
Pin control by itself supports multiple states.
I am not sure if this has a usecase with this device though.

> 
> > +    type: object
> > +    patternProperties:
> > +      "-pins$":
> > +        type: object
> > +        properties:
> > +          pins:
> > +            $ref: /schemas/pinctrl/pinmux-node.yaml#/properties/pins
> > +            items:
> > +              enum:
> > +                - int1
> > +                - int2
> > +
> > +          function:
> > +            $ref: /schemas/types.yaml#/definitions/string
> > +            description: |
> > +              Pin function:
> > +              - ignore:  Preserve the previous state.
> > +              - disable: Disable pin output.
> > +              - wakeup:  Output wakes up the system.
> > +              - clock:   Output clock pulse.
> > +              - pmin1:   Minute periodical output with 50% duty.
> > +              - pmin2:   Minute periodical output L for 7.81 ms.
> > +                         Can only be used with pin int1.
> > +            enum:
> > +              - ignore
> > +              - disable
> > +              - wakeup
> > +              - clock
> > +              - pmin1
> > +              - pmin2
> > +
> > +        required:
> > +          - function
> > +
> > +        additionalProperties: false
> > +
> > +    additionalProperties: false
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > +  - |
> > +    i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        rtc@30 {
> > +            compatible = "sii,s35390a";
> > +            reg = <0x30>;
> > +            pinctrl-0 = <&rtc_pins_default>;
> > +            pinctrl-names = "default";
> > +
> > +            wakeup-parent = <&int>;
> > +
> > +            rtc_pins_default: pins {
> > +              int1-pins {
> > +                pins = "int1";
> > +                function = "wakeup";
> > +              };
> > +              int2-pins {
> > +                pins = "int2";
> > +                function = "disable";
> > +              };
> > +            };
> > +        };
> > +    };
> > diff --git a/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml b/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml
> > index f4d0eed98a08..7b3f682ef4d5 100644
> > --- a/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml
> > +++ b/Documentation/devicetree/bindings/rtc/trivial-rtc.yaml
> > @@ -81,8 +81,6 @@ properties:
> >        - ricoh,rv5c386
> >        # I2C bus SERIAL INTERFACE REAL-TIME CLOCK IC
> >        - ricoh,rv5c387a
> > -      # 2-wire CMOS real-time clock
> > -      - sii,s35390a
> >        # ST SPEAr Real-time Clock
> >        - st,spear600-rtc
> >        # VIA/Wondermedia VT8500 Real-time Clock
> > @@ -105,5 +103,4 @@ required:
> >    - reg
> >  
> >  additionalProperties: false
> > -
> >  ...
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 5114e6db7307..4c8bc35cfe55 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -22695,6 +22695,7 @@ T:	git git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux.git
> >  F:	Documentation/admin-guide/rtc.rst
> >  F:	Documentation/devicetree/bindings/rtc/
> >  F:	drivers/rtc/
> > +F:	include/dt-bindings/rtc/
> >  F:	include/linux/rtc.h
> >  F:	include/linux/rtc/
> >  F:	include/uapi/linux/rtc.h
> > 
> > -- 
> > 2.54.0
> > 

Thanks
- Markus Probst


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