Re: [PATCH v10 3/3] dt-bindings: mfd: Document Renesas R-Car Gen3 RPC-IF controller bindings

From: Sergei Shtylyov
Date: Thu Apr 18 2019 - 12:56:07 EST


Hello!

On 04/18/2019 08:55 AM, masonccyang@xxxxxxxxxxx wrote:

>> > > > Document the bindings used by the Renesas R-Car Gen3 RPC-IF
>> MFD controller.
>> > > >
>> > > > Signed-off-by: Mason Yang <masonccyang@xxxxxxxxxxx>
>> > > > ---
>> > > > .../devicetree/bindings/mfd/mfd-renesas-rpc.txt | 37 +++++++++
>> > > +++++++++++++
>> > > > 1 file changed, 37 insertions(+)
>> > > > create mode 100644 Documentation/devicetree/bindings/mfd/mfd-
>> > > renesas-rpc.txt
>> > > >
>> > > > diff --git a/Documentation/devicetree/bindings/mfd/mfd-renesas-
>> > > rpc.txt b/Documentation/devicetree/bindings/mfd/mfd-renesas-rpc.txt
>> > > > new file mode 100644
>> > > > index 0000000..bfb3d29
>> > > > --- /dev/null
>> > > > +++ b/Documentation/devicetree/bindings/mfd/mfd-renesas-rpc.txt
>> > > > @@ -0,0 +1,37 @@
>> > > > +Renesas R-Car Gen3 RPC-IF MFD controller Device Tree Bindings
>> > > > +-------------------------------------------------------------
>> > > > +
>> > > > +Required properties:
>> > > > +- compatible: should be an SoC-specific compatible value, followed by
>> > > > + "renesas,rcar-gen3-rpc" as a fallback.
>> > > > + supported SoC-specific values are:
>> > > > + "renesas,r8a77995-rpc" (R-Car D3)
>> > > > +- reg: should contain 2 entries, one for the base address of rpc-
>> > > if registers,
>> > > > + and one for the direct mapping area
>> > > > +- reg-names: should contain "regs", and "dirmap"
>> > >
>> > > The device tree describes the hardware, not the driver. Why
>> did you remove
>> > > the "wbuf" area?
>> >
>> > I don't think we should describe the hardware that driver did not
>> implement it
>> > because there are still many RPC registers we don't use them.
>>
>> I have to repeat: we describe the hardware, not the driver capabilities.
>
> how about:
>
> - reg: should contain three register areas:
> first for the base address of rpc-if registers,
> second for the direct mapping read mode and
> third for an optional write buffer area.
> - reg-names: should contain "regs", "dirmap" and "wbuf"(optional).
>
> is it OK ?

No, the write buffer area is always there, at least on the gen3 chips.
(I forgot which other Renesas SoC has RPC-IF as well).

> thanks & best regards,
> Mason

MBR, Sergei