[PATCH v2 3/6] dt-bindings: usb: dwc3: add reference clock period

[Rob Herring]

On Wed, Aug 04, 2021 at 05:05:07PM +0300, Baruch Siach wrote:
> Document the snps,ref-clock-period property that describes reference
> clock period when it deviates from the default set value.
> 
> Signed-off-by: Baruch Siach <baruch at tkos.co.il>
> ---
>  Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> index 41416fbd92aa..c8027d2852cd 100644
> --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> @@ -252,6 +252,15 @@ properties:
>      minimum: 0
>      maximum: 0x3f
>  
> +  snps,ref-clock-period:
> +    description:
> +      Value for REFCLKPER field of GUCTL register for post-silicon reference

Why is post-silicon relevant here? Everything upstream should be for 
post-silicon. I've seen and done the hacks to make pre-silicon testing 
work and we don't need those upstream.

> +      clock period in nanoseconds, when the hardware set default does not match

If you have units, then use property unit suffix in the name.

> +      the actual clock.
> +    $ref: /schemas/types.yaml#/definitions/uint32

And then you can drop the type.

However, if the h/w block gets a ref clock why isn't it described in 
'clocks' and then you can just read why the frequency is and calculate 
the period.