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

[Jassi Brar]

On Fri, Oct 6, 2017 at 4:50 AM, Rob Herring <robh at 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 at kernel.org>
>> Cc: Mark Rutland <mark.rutland at arm.com>
>> Signed-off-by: Sudeep Holla <sudeep.holla at 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.