Re: [RFC 1/2] dt-bindings: clk: versaclock5: Add load capacitance properties

Adam Ford
2021-01-13T12:32:36Z

On Tue, Jan 12, 2021 at 9:16 PM Rob Herring <robh@kernel.org> wrote:
>
> On Wed, Jan 06, 2021 at 11:38:59AM -0600, Adam Ford wrote:
> > There are two registers which can set the load capacitance for
> > XTAL1 and XTAL2. These are optional registers when using an
> > external crystal. Update the bindings to support them.
> >
> > Signed-off-by: Adam Ford <aford173@gmail.com>
> > ---
> > .../devicetree/bindings/clock/idt,versaclock5.yaml | 12 ++++++++++++
> > 1 file changed, 12 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/clock/idt,versaclock5.yaml b/Documentation/devicetree/bindings/clock/idt,versaclock5.yaml
> > index 2ac1131fd922..e5e55ffb266e 100644
> > --- a/Documentation/devicetree/bindings/clock/idt,versaclock5.yaml
> > +++ b/Documentation/devicetree/bindings/clock/idt,versaclock5.yaml
> > @@ -59,6 +59,18 @@ properties:
> > minItems: 1
> > maxItems: 2
> >
> > + idt,xtal1-load-femtofarads:
> > + $ref: /schemas/types.yaml#/definitions/uint32
>
> Already has a type, so you can drop the $ref.
>
> > + minimum: 9000
> > + maximum: 25000

Luca,

Do you want the range to the 9000 - 25000 per the datasheet, or should
I use the max value based on the programmer guide? Currently, my
intent was to cap the value to 11111b, so anyone who writes 23000,
24000, or 25000 will all be the same value based on the feedback I got
from Renesas.

adam
> > + description: Optional loading capacitor for XTAL1
> > +
> > + idt,xtal2-load-femtofarads:
> > + $ref: /schemas/types.yaml#/definitions/uint32
> > + minimum: 9000
> > + maximum: 25000
> > + description: Optional loading capacitor for XTAL2
> > +
> > patternProperties:
> > "^OUT[1-4]$":
> > type: object
> > --
> > 2.25.1
> >