Re: [PATCH v7 1/4] dt-bindings: mfd: Add sony,cronos-smc

[Timothy Pearson <tpearson@raptorengineering.com>]

----- Original Message -----
> From: "Conor Dooley" <conor@kernel.org>
> To: "Raptor Engineering Development Team" <support@raptorengineering.com>
> Cc: "devicetree" <devicetree@vger.kernel.org>, "linux-kernel" <linux-kernel@vger.kernel.org>, "Rob Herring"
> <robh+dt@kernel.org>, "Conor Dooley" <conor+dt@kernel.org>, "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
> "Lee Jones" <lee@kernel.org>, "Georgy Yakovlev" <Georgy.Yakovlev@sony.com>, "Shawn Anastasio"
> <sanastasio@raptorengineering.com>, "Timothy Pearson" <tpearson@raptorengineering.com>
> Sent: Friday, March 6, 2026 11:49:18 AM
> Subject: Re: [PATCH v7 1/4] dt-bindings: mfd: Add sony,cronos-smc

> On Thu, Jan 29, 2026 at 01:20:44PM -0600, Raptor Engineering Development Team
> wrote:
>> From: Shawn Anastasio <sanastasio@raptorengineering.com>
>> 
>> The Sony Cronos Platform Controller is a multi-purpose platform controller
>> that provides both a watchdog timer and an LED controller for the Sony
>> Interactive Entertainment Cronos x86 server platform. As both functions
>> are provided by the same CPLD, a multi-function device is exposed as the
>> parent of both functions.
>> 
>> Add a DT binding for this device.
>> 
>> Signed-off-by: Shawn Anastasio <sanastasio@raptorengineering.com>
>> Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>
>> ---
>>  .../bindings/mfd/sony,cronos-smc.yaml         | 128 ++++++++++++++++++
>>  1 file changed, 128 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/mfd/sony,cronos-smc.yaml
>> 
>> diff --git a/Documentation/devicetree/bindings/mfd/sony,cronos-smc.yaml
>> b/Documentation/devicetree/bindings/mfd/sony,cronos-smc.yaml
>> new file mode 100644
>> index 000000000000..a7e88fd42d39
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/sony,cronos-smc.yaml
>> @@ -0,0 +1,128 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +# Copyright 2025-2026 Raptor Engineering, LLC
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/mfd/sony,cronos-smc.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Sony Cronos Platform Controller CPLD multi-function device
>> +
>> +maintainers:
>> +  - Georgy Yakovlev <Georgy.Yakovlev@sony.com>
>> +
>> +description:
>> +  The Sony Cronos Platform Controller CPLD is a multi-purpose platform
>> +  controller that provides both a watchdog timer and an LED controller for the
>> +  Sony Interactive Entertainment Cronos x86 server platform. As both functions
>> +  are provided by the same CPLD, a multi-function device is exposed as the
>> +  parent of both functions.
>> +
>> +properties:
>> +  compatible:
>> +    const: sony,cronos-smc
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  leds:
>> +    type: object
>> +    $ref: /schemas/leds/common.yaml#
>> +    additionalProperties: false
>> +    description: |
>> +      The Cronos LED controller is a subfunction of the Cronos platform
>> +      controller, which is a multi-function device.
>> +
>> +      Each led is represented as a child node of sony,cronos-led. Fifteen RGB
>> +      LEDs are supported by the platform.
>> +
>> +    properties:
>> +      compatible:
>> +        const: sony,cronos-led
>> +
>> +      reg:
>> +        maxItems: 1
>> +
>> +      "#address-cells":
>> +        const: 1
>> +
>> +      "#size-cells":
>> +        const: 0
>> +
>> +    patternProperties:
>> +      "^multi-led@[0-9a-f]$":
>> +        type: object
>> +        $ref: /schemas/leds/leds-class-multicolor.yaml#
>> +        unevaluatedProperties: false
>> +
>> +        properties:
>> +          reg:
>> +            description:
>> +              LED channel number (0..14)
>> +            minimum: 0
>> +            maximum: 14
>> +
>> +        required:
>> +          - reg
>> +
>> +    required:
>> +      - compatible
>> +      - "#address-cells"
>> +      - "#size-cells"
>> +
>> +  watchdog:
>> +    type: object
>> +
>> +    $ref: /schemas/watchdog/watchdog.yaml
>> +
>> +    properties:
>> +      compatible:
>> +        const: sony,cronos-watchdog
>> +
>> +      timeout-sec: true
> 
> Why is there a child node to just add timeout-sec?

When I tried Krzysztof's solution, the validation tools threw an error, and this was the only way I found to get them to stop throwing errors.

> Didn't Krzysztof ask
> you to come up with a generic node name for the mfd to use instead of
> "smc", and to modify watchdog.yaml to accept the new node name? See
> here:
> https://lore.kernel.org/all/c7630eb1-2686-491e-81ed-fb43fff2dd31@linaro.org/
> 
> Something like "platform-controller" sounds generic to me, in a way that
> "smc" doesn't.

SMC is the name of the hardware block in question.  platform-controller generates some other confusion as there would be multiple separate hardware blocks that could fit that name.

> 
>> +
>> +    required:
>> +      - compatible
>> +
>> +    additionalProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/leds/common.h>
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        smc@3f {
>> +            compatible = "sony,cronos-smc";
>> +            reg = <0x3f>;
>> +
>> +            watchdog {
>> +                compatible = "sony,cronos-watchdog";
>> +
>> +                timeout-sec = <20>;
>> +            };
>> +
>> +            leds {
>> +                compatible = "sony,cronos-led";
>> +                #address-cells = <1>;
>> +                #size-cells = <0>;
>> +
>> +                multi-led@0 {
>> +                    /*
>> +                     * No subnodes are needed, this controller only supports
>> RGB
>> +                     * LEDs.
>> +                     */
>> +                    reg = <0>;
>> +                    color = <LED_COLOR_ID_MULTI>;
>> +                    function = LED_FUNCTION_STATUS;
>> +                };
>> +            };
>> +        };
>> +    };
>> +
>> --
>> 2.39.5