Re: [PATCH v7 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[Krzysztof Kozlowski <krzk@kernel.org>]

On 10/06/2026 09:15, Can Guo wrote:
> UFS v5.0/UFSHCI v5.0 add HS-G6 support via UniPro v3.0 and M-PHY v6.0.
> These specs define TX Equalization for all High Speed Gears, and HS-G6 may
> also require TX precode depending on channel characteristics.
> 
> Document vendor-neutral DT properties in ufs-common.yaml:
> 
> - patternProperties for txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6]
> - tx-precode-g6-host-lanes
> - tx-precode-g6-device-lanes
> 
> txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6] accept per-lane tuples:
> <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>]

Instead of repeating the diff, you should explain why these properties
are needed. Insufficient explanation was also pointed out at v1.

Why this cannot be deduced from the IP compatible? Does it depend on the
device memory? Who determines the values here and what do they depend
on? Also here you explain lack of auto tuning for example.

> 
> PreShoot and DeEmphasis values are 0..7 and accept 2 or 4 values for x1/x2
> lane configurations.
> 

...


> +      Lane indices for static Host-side TX precode enable settings for HS-G6
> +      only. Listed lanes have precode enabled; unlisted lanes are disabled.
> +
> +  tx-precode-g6-device-lanes:
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    minItems: 1
> +    maxItems: 2
> +    uniqueItems: true
> +    items:
> +      minimum: 0
> +      maximum: 1
> +    description: |
> +      Lane indices for static Device-side TX precode enable settings for HS-G6
> +      only. Listed lanes have precode enabled; unlisted lanes are disabled.


I need to reverse my opinion and let's go to v6 implementation. These
properties look more consistent in v6 with respect to preshoot and
deepmhasis properties.

You want actually matrix, so:

  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.

And similar style with items also for preshoot and deepmhasis.


Best regards,
Krzysztof