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

- From: Rob Herring \<robh@kernel.org\>
- Date: 2021-12-21 17:55:42 
- List: linux-crypto
- Page: https://ratatoskr.run/linux-crypto/2021/12/1615875
- Thread: https://ratatoskr.run/linux-gpio/2021/12/1612014/t.md

```text
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?

> +
> +  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.

Rob
```