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

Johnson Wang (王聖鑫)
2022-10-06T11:24:19Z

On Fri, 2022-09-30 at 14:07 -0500, Rob Herring wrote:
> 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
> > > +---
> > > +$id:
> > > https://urldefense.com/v3/__http://devicetree.org/schemas/arm/mediatek/mediatek,mt8186-fhctl.yaml*__;Iw!!CTRNKA9wMg0ARbw!xVt73f8PaQKph8n0ffGHHmQIxdzooUtGr0xDNVqy_6V0vwcs5k-FLrmkB3PZupSu1ciC$
> > >
> > > +$schema:
> > > https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!xVt73f8PaQKph8n0ffGHHmQIxdzooUtGr0xDNVqy_6V0vwcs5k-FLrmkB3PZulXwBACk$
> > >
> > > +
> > > +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.
>

Hi Rob,

Thanks for the explanation.

Then I will keep this example the same in the next version.

BRs,
Johnson Wang
> >
> > #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>
> >