Re: [PATCH v3 03/22] dt-bindings: arm: scmi: add ARM MHU specific mailbox client bindings

[Rob Herring <robh@kernel.org>]

On Fri, Oct 6, 2017 at 6:01 AM, Jassi Brar <jassisinghbrar@gmail.com> wrote:
> On Fri, Oct 6, 2017 at 4:50 AM, Rob Herring <robh@kernel.org> wrote:
>> On Thu, Sep 28, 2017 at 02:11:27PM +0100, Sudeep Holla wrote:
>>> This patch adds ARM MHU specific mailbox client bindings to support
>>> SCMI. Since SCMI specification just requires doorbell mechanism from
>>> mailbox controllers, we add mailbox data to specify the doorbell bit(s).
>>>
>>> Cc: Rob Herring <robh+dt@kernel.org>
>>> Cc: Mark Rutland <mark.rutland@arm.com>
>>> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
>>> ---
>>>  .../devicetree/bindings/arm/arm,mhu-scmi.txt          | 19 +++++++++++++++++++
>>>  1 file changed, 19 insertions(+)
>>>  create mode 100644 Documentation/devicetree/bindings/arm/arm,mhu-scmi.txt
>>>
>>> diff --git a/Documentation/devicetree/bindings/arm/arm,mhu-scmi.txt b/Documentation/devicetree/bindings/arm/arm,mhu-scmi.txt
>>> new file mode 100644
>>> index 000000000000..8c106f1cdeb8
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/arm/arm,mhu-scmi.txt
>>> @@ -0,0 +1,19 @@
>>> +ARM MHU mailbox client bindings for SCMI Message Protocol
>>> +----------------------------------------------------------
>>> +
>>> +This binding is intended to define the ARM MHU specific extensions to
>>> +the generic SCMI bindings[2].
>>> +
>>> +Required properties:
>>> +
>>> +The scmi node with the following properties shall be under the /firmware/ node.
>>> +
>>> +- compatible : shall be "arm,scmi" and "arm,mhu-scmi"
>>
>> Most specific first.
>>
>>> +- mbox-data : For each phandle listed in mboxes property, an unsigned 32-bit
>>> +           data as expected by the mailbox controller
>>
>> Shouldn't that be cells as part of mboxes property?
>>
> A MHU client can send any number of commands (such u32 values) over a channel.
> This client (SCMI) sends just one command over a channel, but other
> clients may/do send two or more.

Okay, then I guess I don't understand why this is in DT.

Rob