Re: [PATCH v2 03/17] dt-bindings: soc/microchip: make systemcontroller a mfd

[conor dooley <mail@conchuod.ie>]

On Tuesday, December 21st, 2021 at 17:55, Rob Herring <robh@kernel.org> wrote:

>On Fri, Dec 17, 2021 at 09:33:11AM +0000, conor.dooley@microchip.com wrote:
>> From: Conor Dooley <conor.dooley@microchip.com>
>>
>> Make the system controller on the Polarfire SoC
>> a "simple,mfd" so that the services can be child
>> nodes of the system controller node.
>>
>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>> ---
>>  .../microchip,mpfs-sys-controller.yaml        | 33 +++++++++++++++++--
>>  1 file changed, 30 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-sys-controller.yaml b/>Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-sys-controller.yaml
>> index f699772fedf3..014cb44b8f31 100644
>> --- a/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-sys-controller.yaml
>> +++ b/Documentation/devicetree/bindings/soc/microchip/microchip,mpfs-sys-controller.yaml
>> @@ -13,13 +13,34 @@ description: |
>>    The PolarFire SoC system controller is communicated with via a mailbox.
>>    This document describes the bindings for the client portion of that mailbox.
>>
>> -
>>  properties:
>>    mboxes:
>>      maxItems: 1
>>
>>    compatible:
>> -    const: microchip,mpfs-sys-controller
>> +    items:
>> +      - const: microchip,mpfs-sys-controller
>> +      - const: simple-mfd
>
>'simple-mfd' means there is zero dependency on the parent for the child
>nodes. Isn't 'mboxes' a dependency?

I suppose it is. I was going off what had been done for the bcm2835
firmware for the rpi its also a mailbox providing "services".
(arm/bcm/raspberrypi,bcm2835-firmware.yaml)
>
>> +
>> +  hwrandom:
>> +    type: object
>> +
>> +    properties:
>> +      compatible:
>> +        const: microchip,mpfs-rng
>> +
>> +    required:
>> +      - compatible
>> +
>> +  sysserv:
>> +    type: object
>> +
>> +    properties:
>> +      compatible:
>> +        const: microchip,mpfs-generic-service
>> +
>> +    required:
>> +      - compatible
>
>There's not really any need to have child nodes which have no resources.
>The driver for microchip,mpfs-sys-controller can create child devices.

I am assuming by this you mean say, take a list of boolean properties and
convert those into child devices? There's a fairly decent number of services
provided by the system controller and these children just represent the
subset that we've implemented so far.

Conor
>
>Rob