Re: [PATCH v2 1/3] dt-bindings: phy: imx8mq-usb: improve some tuning properties

Xu Yang
2025-04-30T06:11:51Z

On Tue, Apr 29, 2025 at 04:10:13PM +0100, Conor Dooley wrote:
> On Tue, Apr 29, 2025 at 11:30:07AM +0800, Xu Yang wrote:
> > Commit b2e75563dc39 ("dt-bindings: phy: imx8mq-usb: add phy tuning
> > properties") add many tuning properties, but some parameter value doesn't
> > match the register description. It made some changes based on the original
> > value: add offset to a negative number so turn it to a non-negative number.
> > However, it's not easy to find an exact tuning value from register field
> > with such conversion.
> >
> > Because device-tree supports negative parameter number, this will improve
> > some propertie's parameter.
> >
> > Mainly include below properties:
> > - fsl,phy-tx-vref-tune-percent
> > - fsl,phy-tx-rise-tune-percent
> > - fsl,phy-comp-dis-tune-percent
> >
> > The parameter value of above 3 properties are USB PHY specific. i.MX8MP
> > and i.MX95 USB PHY has different meanings. So this add restrictions for
> > them.
>
> It's hard for me to understand from this if you're actually changing the
> meaning of the property. Will the current/old values continue to
> function as they have been?

Unfortunately no. I am going to rework it according to KK's comments.
Sorry to bother you.

Thanks,
Xu Yang

>
> >
> > - fsl,phy-tx-vboost-level-microvolt
> >
> > For this property, the parameter value is wrong in register description.
> > This will correct it according to true value.
> >
> > For detailed info, please refer to i.MX8MP and i.MX95 latest reference
> > manual.
> >
> > Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> >
> > ---
> > Changes in v2:
> > - keep widest constraints
> > - use multipleOf for some properties
> > ---
> > .../bindings/phy/fsl,imx8mq-usb-phy.yaml | 60 +++++++++++++++----
> > 1 file changed, 49 insertions(+), 11 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml
> > index daee0c0fc915..71e5940ef4b8 100644
> > --- a/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml
> > +++ b/Documentation/devicetree/bindings/phy/fsl,imx8mq-usb-phy.yaml
> > @@ -42,16 +42,17 @@ properties:
> >
> > fsl,phy-tx-vref-tune-percent:
> > description:
> > - Tunes the HS DC level relative to the nominal level
> > - minimum: 94
> > - maximum: 124
> > + Tunes the HS DC level relative to the nominal level. It varies
> > + between different PHY versions
> > + minimum: -1000
> > + maximum: 875
> >
> > fsl,phy-tx-rise-tune-percent:
> > description:
> > Adjusts the rise/fall time duration of the HS waveform relative to
> > - its nominal value
> > - minimum: 97
> > - maximum: 103
> > + its nominal value. It varies between different PHY versions
> > + minimum: -10
> > + maximum: 20
> >
> > fsl,phy-tx-preemp-amp-tune-microamp:
> > description:
> > @@ -63,15 +64,14 @@ properties:
> > fsl,phy-tx-vboost-level-microvolt:
> > description:
> > Adjust the boosted transmit launch pk-pk differential amplitude
> > - minimum: 880
> > - maximum: 1120
> > + enum: [844, 1008, 1156]
> >
> > fsl,phy-comp-dis-tune-percent:
> > description:
> > Adjust the voltage level used to detect a disconnect event at the host
> > - relative to the nominal value
> > - minimum: 91
> > - maximum: 115
> > + relative to the nominal value. It varies between different PHY versions
> > + minimum: -60
> > + maximum: 45
> >
> > fsl,phy-pcs-tx-deemph-3p5db-attenuation-db:
> > description:
> > @@ -112,6 +112,44 @@ allOf:
> > reg:
> > maxItems: 1
> >
> > + - if:
> > + properties:
> > + compatible:
> > + enum:
> > + - fsl,imx8mq-usb-phy
> > + - fsl,imx8mp-usb-phy
> > + then:
> > + properties:
> > + fsl,phy-tx-vref-tune-percent:
> > + minimum: -6
> > + maximum: 24
> > + multipleOf: 2
> > + fsl,phy-tx-rise-tune-percent:
> > + enum: [-3, -1, 0, 3]
> > + fsl,phy-comp-dis-tune-percent:
> > + enum: [-9, -6, -3, 0, 4, 7, 11, 15]
> > +
> > + - if:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - fsl,imx95-usb-phy
> > + then:
> > + properties:
> > + fsl,phy-tx-vref-tune-percent:
> > + description: 100x the original
> > + minimum: -1000
> > + maximum: 875
> > + multipleOf: 125
> > + fsl,phy-tx-rise-tune-percent:
> > + enum: [-10, 0, 15, 20]
> > + fsl,phy-comp-dis-tune-percent:
> > + description: 10x the original
> > + minimum: -60
> > + maximum: 45
> > + multipleOf: 15
> > +
> > - if:
> > required:
> > - orientation-switch
> > --
> > 2.34.1
> >