Re: [PATCH 06/13] dt-bindings: rng: add bindings for microchip mpfs rng

[Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxx>]

On 09/11/2021 13:54, Conor.Dooley@xxxxxxxxxxxxx wrote:
> On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> On 08/11/2021 16:05, conor.dooley@xxxxxxxxxxxxx wrote:
>>> From: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>>>
>>> Add device tree bindings for the hardware rng device accessed via
>>> the system services on the Microchip PolarFire SoC.
>>>
>>> Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>>> ---
>>>   .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>>   1 file changed, 31 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>> new file mode 100644
>>> index 000000000000..e8ecb3538a86
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>> @@ -0,0 +1,31 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#";
>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#";
>>> +
>>> +title: Microchip MPFS random number generator
>>> +
>>> +maintainers:
>>> +  - Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: microchip,polarfire-soc-rng
>>> +
>>> +  syscontroller:
>>> +    maxItems: 1
>>> +    description: name of the system controller device node
>>
>> There are several issues with this:
>> 1. You need to describe the type.
>> 2. Description is not helpful (just copying the name of property) and
>> actually misleading because you do not put there the name of device node.
>> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
>> please use existing syscon bindings.
> 1 & 2 - Correct, it is bad & I'll write a better description for it.
> 3 - Its a system controller implemented as a mailbox. The syscontroller 
> is the mailbox client, which the rng and generic drivers both use.

I understood that pointed device node is a mailbox, not this node. But
here, what is it here? How do you use it here?

Best regards,
Krzysztof