[PATCH v4 2/4] dt-bindings: arm: mediatek: Add new bindings of MediaTek frequency hopping

Johnson Wang (王聖鑫) Johnson.Wang at mediatek.com
Mon Oct 17 05:55:09 PDT 2022


On Fri, 2022-10-14 at 13:42 -0700, Stephen Boyd wrote:
> Quoting Johnson Wang (2022-10-13 04:23:34)
> > Add the new binding documentation for MediaTek frequency hopping
> > and spread spectrum clocking control.
> > 
> > Co-developed-by: Edward-JW Yang <edward-jw.yang at mediatek.com>
> > Signed-off-by: Edward-JW Yang <edward-jw.yang at mediatek.com>
> > Signed-off-by: Johnson Wang <johnson.wang at mediatek.com>
> > Reviewed-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno at collabora.com>
> > Reviewed-by: Rob Herring <robh at kernel.org>
> > ---
> >  .../arm/mediatek/mediatek,mt8186-fhctl.yaml   | 53
> > +++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> >  create mode 100644
> > Documentation/devicetree/bindings/arm/mediatek/mediatek,mt8186-
> > fhctl.yaml
> > 
> > diff --git
> > a/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt8186-
> > fhctl.yaml
> > b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt8186-
> > fhctl.yaml
> > new file mode 100644
> > index 000000000000..59111946966c
> > --- /dev/null
> > +++
> > b/Documentation/devicetree/bindings/arm/mediatek/mediatek,mt8186-
> > fhctl.yaml
> > @@ -0,0 +1,53 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: 
> > https://urldefense.com/v3/__http://devicetree.org/schemas/arm/mediatek/mediatek,mt8186-fhctl.yaml*__;Iw!!CTRNKA9wMg0ARbw!yfDH4W14Pek7w3YBrdcBAGj3OSSWGlWk8av4DmHT69Ej4ax75zKqpy89ZvX1Z_aKDPzu$
> >  
> > +$schema: 
> > https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!yfDH4W14Pek7w3YBrdcBAGj3OSSWGlWk8av4DmHT69Ej4ax75zKqpy89ZvX1Z9gRczPi$
> >  
> > +
> > +title: MediaTek frequency hopping and spread spectrum clocking
> > control
> 
> The driver patch is in drivers/clk so why not put the binding in
> bindings/clock as well?
> 
Hi Stephen,

Sure, I will move this binding in the next version.

> > +
> > +maintainers:
> > +  - Edward-JW Yang <edward-jw.yang at mediatek.com>
> > +
> 
> [...]
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - clocks
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/clock/mt8186-clk.h>
> > +    fhctl: fhctl at 1000ce00 {
> 
> Is it a clock-controller? 'fhctl' isn't a generic node name.
> 

This node is used for determining if PLLs adopt "hopping" method to
adjust their frequency.
It doesn't provide any clock but actually change the behavior of some
PLLs with new .set_rate callback.
Do you think this node acts like one kind of clock-controller?


BRs,
Johnson Wang
> > +        compatible = "mediatek,mt8186-fhctl";
> > +        reg = <0x1000ce00 0x200>;
> > +        clocks = <&apmixedsys CLK_APMIXED_MSDCPLL>;
> > +        mediatek,hopping-ssc-percent = <3>;


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