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: "Timothy Pearson" <tpearson@raptorengineering.com>
> Cc: "Raptor Engineering Development Team" <support@raptorengineering.com>, "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>
> Sent: Friday, March 6, 2026 12:14:19 PM
> Subject: Re: [PATCH v7 1/4] dt-bindings: mfd: Add sony,cronos-smc

> On Fri, Mar 06, 2026 at 11:52:23AM -0600, Timothy Pearson wrote:
>> 
>> 
>> ----- 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.
> 
> So you were not able to do what he did, and modify watchdog.yaml?
> What did you try, and what were the 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.
> 
> Node names do not have to be unique. If there are 10 platform controllers
> on the platform, then having 10 platform-controller@<foo> nodes would be
> fine. We explicitly want node-names to describe the type of device, not
> be a unique identifier. That's what compatible strings are for.
> I'm unsure why there would be any confusion caused by the node name,
> can you elaborate on that? What other devices connected to the BMC would
> be considered "platform controllers"?
> 
> There's no explanation anywhere here where "smc" even comes from, none
> of the description text or commit message has something that I would
> expect "smc" to be shorthand for.

Understood.  Let me rework.  I'll see if I can provoke the error regarding the watchdog YAML again as well.  It may be a couple of weeks before I respond as I have other active projects at this time.

Thanks!