Re: [PATCH v8 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[Can Guo]

On 6/15/2026 7:26 PM, Krzysztof Kozlowski wrote:
> On 15/06/2026 10:50, Can Guo wrote:
> > UFS v5.0/UFSHCI v5.0 adds HS-G6 support (46.6 Gbps/lane) via UniPro
> > v3.0 and M-PHY v6.0. These specs define TX Equalization for all
> > High-Speed Gears (not only HS-G6) to compensate channel loss and
> > improve signal integrity at high speed.
> >
> > For HS-G6, M-PHY uses PAM4 1b1b line coding. Pre-Coding may also be
> > required depending on channel characteristics.
> >
> > Document vendor-neutral properties in ufs-common.yaml:
> > - txeq-preshoot-g[1-6]
> > - txeq-deemphasis-g[1-6]
> > - tx-precode-enable-g6
> >
> > Values are per-lane Host/Device tuples (2 values for x1, 4 values for
> > x2). PreShoot/DeEmphasis range from 0..7, and Precode is 0/1.
> >
> > These are board-specific signal-integrity tuning values. They depend on
> > channel SI/PHY characterization and validation (host PHY, device PHY,
> > package, and board routing), and are determined by HW/PHY designers.
> >
> > Although UFSHCI v5.0 supports TX Equalization Training via UniPro v3.0,
> > which allows host software to determine optimal TX Equalization at
> > runtime, static board-specific TX Equalization settings in the Device
> > Tree are still necessary because:
> > - TX Equalization Training is not supported for HS-G3 and below
> > - TX Equalization Training is disabled on some platforms
> >
> > Signed-off-by: Can Guo <can.guo@xxxxxxxxxxxxxxxx>
> > ---
> >   .../devicetree/bindings/ufs/ufs-common.yaml   | 55 +++++++++++++++++++
> >   1 file changed, 55 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> > index ed97f5682509..145a6416e1df 100644
> > --- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> > +++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> > @@ -105,6 +105,61 @@ properties:
> >         Restricts the UFS controller to rate-a or rate-b for both TX and
> >         RX directions.
> >   
> > +  tx-precode-enable-g6:
> > +    $ref: /schemas/types.yaml#/definitions/uint32-matrix
> > +    oneOf:
> > +      - items:
> > +          - description: Host_Lane0 precode
> > +          - description: Device_Lane0 precode
> > +      - items:
> > +          - description: Host_Lane0 precode
> > +          - description: Device_Lane0 precode
> > +          - description: Host_Lane1 precode
> > +          - description: Device_Lane1 precode
> > +    items:
> > +      enum: [0, 1]
> > +    description:
> > +      Static TX Precode enable values for HS-G6 only.
> My bad here, that was my mistake. I wanted matrix, but gave you array
> syntax. Proper code would be:
>
>    tx-precode-enable-g6:
>      $ref: /schemas/types.yaml#/definitions/uint32-matrix
>      minItems: 1
>      items:
>        - items:
>            - description: Host_Lane0 precode
>              enum: [0, 1]
>            - description: Device_Lane0 precode
>              enum: [0, 1]
>        - items:
>            - description: Host_Lane1 precode
>              enum: [0, 1]
>            - description: Device_Lane1 precode
>              enum: [0, 1]
>      description:
>        Static TX Precode enable values for HS-G6 only.
>
>
> I tested it with DTS and seems to work fine. Please use the same for
> other properties, but enum will be 0-7.
Sure, I will correct it and validate the same for the next version.

Thank you for helping me out.

Best Regards,
Can Guo.
> Best regards,
> Krzysztof