RE: [PATCH v2 2/4] dt-bindings: snps,dw-apb-ssi: Add optional clock domain information

[Gareth Williams]

Hi Rob,

On Tue, Oct 01, 2019 at 13:02:34AM +0100, Rob Herring wrote:
> On Wed, Sep 18, 2019 at 09:04:34AM +0100, Gareth Williams wrote:
> > Note in the bindings documentation that pclk should be renamed if a
> > clock domain is used to enable the optional bus clock.
> >
> > Signed-off-by: Gareth Williams <gareth.williams.jx@xxxxxxxxxxx>
> > ---
> > v2: Introduced this patch.
> > ---
> >  Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> > b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> > index f54c8c3..3ed08ee 100644
> > --- a/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> > +++ b/Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.txt
> > @@ -16,7 +16,8 @@ Required properties:
> >  Optional properties:
> >  - clock-names : Contains the names of the clocks:
> >      "ssi_clk", for the core clock used to generate the external SPI clock.
> > -    "pclk", the interface clock, required for register access.
> > +    "pclk", the interface clock, required for register access. If a clock domain
> > +     used to enable this clock then it should be named "pclk_clkdomain".
> 
> What's a clock domain?
> 
> Unless this is a h/w difference in the IP block, then this change doesn't make
> sense.
This is a reference to the use of clock domains that are implemented through
generic power domains. The domain is implemented in 
drivers/clk/renesas/r9a06g032-clocks.c and general details of clock domains
can be found at 
https://elinux.org/images/1/14/Last_One_Out%2C_Turn_Off_The_Lights.pdf

> 
> >  - cs-gpios : Specifies the gpio pins to be used for chipselects.
> >  - num-cs : The number of chipselects. If omitted, this will default to 4.
> >  - reg-io-width : The I/O register width (in bytes) implemented by
> > this
> > --
> > 2.7.4
> >