[PATCH v6 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[PATCH v6 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[Can Guo]

UFS v5.0/UFSHCI v5.0 add HS-G6 support (46.6 Gbps/lane) via UniPro v3.0
and M-PHY v6.0. In these specs, TX Equalization is defined for all High
Speed Gears (not only HS-G6) to compensate channel loss and improve signal
integrity at high speed operation.

For HS-G6, M-PHY uses PAM4 1b1b line coding, Pre-Coding may also be
required depending on channel characteristics.

Add vendor-neutral DT properties:

- patternProperties for txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6]
- fixed property tx-precode-enable-g6

Each property is a uint32 array of per-lane tuples:
<Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>]

Accept 2 or 4 values (x1/x2 lane configs). PreShoot and DeEmphasis values
are 0..7. Precode enable values are 0/1 and only applicable to HS-G6.

Acked-by: Manivannan Sadhasivam <mani@kernel.org>
Reviewed-by: Bean Huo <beanhuo@micron.com>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
---
 .../devicetree/bindings/ufs/ufs-common.yaml   | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
index ed97f5682509..d90cf25adfa5 100644
--- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
+++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
@@ -105,6 +105,51 @@ properties:
       Restricts the UFS controller to rate-a or rate-b for both TX and
       RX directions.
 
+  tx-precode-enable-g6:
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    oneOf:
+      - minItems: 2
+        maxItems: 2
+      - minItems: 4
+        maxItems: 4
+    items:
+      enum: [0, 1]
+    description: |
+      Static TX Precode enable values for HS-G6 only.
+      Values are specified as per-lane tuples:
+      <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>].
+
+patternProperties:
+  "^txeq-preshoot-g[1-6]$":
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    oneOf:
+      - minItems: 2
+        maxItems: 2
+      - minItems: 4
+        maxItems: 4
+    items:
+      minimum: 0
+      maximum: 7
+    description: |
+      Static TX Equalization PreShoot values for High Speed Gears.
+      Values are specified as per-lane tuples:
+      <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>].
+
+  "^txeq-deemphasis-g[1-6]$":
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    oneOf:
+      - minItems: 2
+        maxItems: 2
+      - minItems: 4
+        maxItems: 4
+    items:
+      minimum: 0
+      maximum: 7
+    description: |
+      Static TX Equalization DeEmphasis values for High Speed Gears.
+      Values are specified as per-lane tuples:
+      <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>].
+
 dependencies:
   freq-table-hz: [ clocks ]
   operating-points-v2: [ clocks, clock-names ]
-- 
2.34.1

Re: [PATCH v6 1/2] dt-bindings: ufs: Document static TX Equalization settings properties

[Krzysztof Kozlowski]

On Fri, May 29, 2026 at 04:33:37AM -0700, Can Guo wrote:
> UFS v5.0/UFSHCI v5.0 add HS-G6 support (46.6 Gbps/lane) via UniPro v3.0
> and M-PHY v6.0. In these specs, TX Equalization is defined for all High
> Speed Gears (not only HS-G6) to compensate channel loss and improve signal
> integrity at high speed operation.
> 
> For HS-G6, M-PHY uses PAM4 1b1b line coding, Pre-Coding may also be
> required depending on channel characteristics.
> 
> Add vendor-neutral DT properties:
> 
> - patternProperties for txeq-preshoot-g[1-6] and txeq-deemphasis-g[1-6]
> - fixed property tx-precode-enable-g6
> 
> Each property is a uint32 array of per-lane tuples:
> <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>]
> 
> Accept 2 or 4 values (x1/x2 lane configs). PreShoot and DeEmphasis values
> are 0..7. Precode enable values are 0/1 and only applicable to HS-G6.
> 
> Acked-by: Manivannan Sadhasivam <mani@kernel.org>
> Reviewed-by: Bean Huo <beanhuo@micron.com>
> Reviewed-by: Peter Wang <peter.wang@mediatek.com>
> Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
> ---
>  .../devicetree/bindings/ufs/ufs-common.yaml   | 45 +++++++++++++++++++
>  1 file changed, 45 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> index ed97f5682509..d90cf25adfa5 100644
> --- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> +++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> @@ -105,6 +105,51 @@ 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-array
> +    oneOf:
> +      - minItems: 2
> +        maxItems: 2
> +      - minItems: 4
> +        maxItems: 4
> +    items:
> +      enum: [0, 1]
> +    description: |
> +      Static TX Precode enable values for HS-G6 only.
> +      Values are specified as per-lane tuples:
> +      <Host_Lane0 Device_Lane0>, [<Host_Lane1 Device_Lane1>].

You need to include them in any of applicable examples, otherwise
nothing here is validated.

Why values cannot be on or off? Or even better: why you cannot just list
all the lanes which has it enabled, assuming disabled is by default?

> +
> +patternProperties:
> +  "^txeq-preshoot-g[1-6]$":
> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> +    oneOf:
> +      - minItems: 2
> +        maxItems: 2
> +      - minItems: 4
> +        maxItems: 4
> +    items:
> +      minimum: 0
> +      maximum: 7

What is the meaning of values? Nothing here refers to the spec, so is
this driver specific?

Best regards,
Krzysztof