Re: [PATCH v3 2/4] dt-bindings: arm: mediatek: Add new bindings of MediaTek frequency hopping

Rob Herring
2022-09-30T19:07:08Z

On Thu, Sep 29, 2022 at 03:07:49PM +0200, AngeloGioacchino Del Regno wrote:
> Il 29/09/22 13:46, Johnson Wang ha scritto:
> > Add the new binding documentation for MediaTek frequency hopping
> > and spread spectrum clocking control.
> >
> > Co-developed-by: Edward-JW Yang <edward-jw.yang@mediatek.com>
> > Signed-off-by: Edward-JW Yang <edward-jw.yang@mediatek.com>
> > Signed-off-by: Johnson Wang <johnson.wang@mediatek.com>
> > ---
> > .../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..258dff7ce6bc
> > --- /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
> > +---
> > +$id: http://devicetree.org/schemas/arm/mediatek/mediatek,mt8186-fhctl.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: MediaTek frequency hopping and spread spectrum clocking control
> > +
> > +maintainers:
> > + - Edward-JW Yang <edward-jw.yang@mediatek.com>
> > +
> > +description: |
> > + Frequency hopping control (FHCTL) is a piece of hardware that control
> > + some PLLs to adopt "hopping" mechanism to adjust their frequency.
> > + Spread spectrum clocking (SSC) is another function provided by this hardware.
> > +
> > +properties:
> > + compatible:
> > + const: mediatek,mt8186-fhctl
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + clocks:
> > + description: Phandles of the PLL with FHCTL hardware capability.
> > + minItems: 1
> > + maxItems: 30
> > +
> > + mediatek,hopping-ssc-percent:
> > + description: The percentage of spread spectrum clocking for one PLL.
> > + minItems: 1
> > + maxItems: 30
> > + items:
> > + default: 0
> > + minimum: 0
> > + maximum: 8
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - clocks
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/clock/mt8186-clk.h>
> > + fhctl: fhctl@1000ce00 {
> > + compatible = "mediatek,mt8186-fhctl";
> > + reg = <0x1000c000 0xe00>;
> > + clocks = <&apmixedsys CLK_APMIXED_MSDCPLL>;
> > + mediatek,hopping-ssc-percent = <3>;
> > + };
>
>
> .... a more realistic example:

One or 2 cells is really outside the scope of the binding as either is
valid. If the parent bus only has 32-bits of address space, there's
little reason to use 2 cells.

>
> #include <dt-bindings/clock/mt8186-clk.h>
>
> soc {
> #address-cells = <2>;
> #size-cells = <2>;
>
> fhctl: fhctl@1000ce00 {
> compatible = "mediatek,mt8186-fhctl";
> reg = <0 0x1000c000 0 0xe00>;
> clocks = <&apmixedsys CLK_APMIXED_MSDCPLL>;
> mediatek,hopping-ssc-percent = <3>;
> };
> };
>
> After which...
>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
>