Add optional "limit-hs-gear" and "limit-rate" properties to the
UFS controller common binding. These properties allow limiting
the maximum HS gear and rate.

This is useful in cases where the customer board may have signal
integrity, clock configuration or layout issues that prevent reliable
operation at higher gears. Such limitations are especially critical in
those platforms, where stability is prioritized over peak performance.

Signed-off-by: Ram Kumar Dwivedi <quic_rdwivedi@quicinc.com>
---
 .../devicetree/bindings/ufs/ufs-common.yaml      | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
index 31fe7f30ff5b..b4c99fee552f 100644
--- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
+++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
@@ -89,6 +89,22 @@ properties:
 
   msi-parent: true
 
+  limit-hs-gear:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 1
+    maximum: 5
+    default: 5
+    description:
+      Restricts the maximum HS gear used in both TX and RX directions.
+
+  limit-rate:
+    $ref: /schemas/types.yaml#/definitions/string
+    enum: [Rate-A, Rate-B]
+    default: Rate-B
+    description:
+      Restricts the UFS controller to Rate A or Rate B for both TX and
+      RX directions.
+
 dependencies:
   freq-table-hz: [ clocks ]
   operating-points-v2: [ clocks, clock-names ]
-- 
2.50.1

On 01/09/2025 17:57, Ram Kumar Dwivedi wrote:
> Add optional "limit-hs-gear" and "limit-rate" properties to the
> UFS controller common binding. These properties allow limiting
> the maximum HS gear and rate.
> 
> This is useful in cases where the customer board may have signal
> integrity, clock configuration or layout issues that prevent reliable
> operation at higher gears. Such limitations are especially critical in
> those platforms, where stability is prioritized over peak performance.
> 
> Signed-off-by: Ram Kumar Dwivedi <quic_rdwivedi@quicinc.com>
> ---
>  .../devicetree/bindings/ufs/ufs-common.yaml      | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> index 31fe7f30ff5b..b4c99fee552f 100644
> --- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> +++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
> @@ -89,6 +89,22 @@ properties:
>  
>    msi-parent: true
>  
> +  limit-hs-gear:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    minimum: 1
> +    maximum: 5

No improvements.

> +    default: 5
> +    description:
> +      Restricts the maximum HS gear used in both TX and RX directions.
> +
> +  limit-rate:
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum: [Rate-A, Rate-B]

lowercase

> +    default: Rate-B


Best regards,
Krzysztof

On 02-Sep-25 11:42 AM, Krzysztof Kozlowski wrote:
> On 01/09/2025 17:57, Ram Kumar Dwivedi wrote:
>> Add optional "limit-hs-gear" and "limit-rate" properties to the
>> UFS controller common binding. These properties allow limiting
>> the maximum HS gear and rate.
>>
>> This is useful in cases where the customer board may have signal
>> integrity, clock configuration or layout issues that prevent reliable
>> operation at higher gears. Such limitations are especially critical in
>> those platforms, where stability is prioritized over peak performance.
>>
>> Signed-off-by: Ram Kumar Dwivedi <quic_rdwivedi@quicinc.com>
>> ---
>>  .../devicetree/bindings/ufs/ufs-common.yaml      | 16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/ufs/ufs-common.yaml b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
>> index 31fe7f30ff5b..b4c99fee552f 100644
>> --- a/Documentation/devicetree/bindings/ufs/ufs-common.yaml
>> +++ b/Documentation/devicetree/bindings/ufs/ufs-common.yaml
>> @@ -89,6 +89,22 @@ properties:
>>  
>>    msi-parent: true
>>  
>> +  limit-hs-gear:
>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    minimum: 1
>> +    maximum: 5
> 
> No improvements.

Hi Krzysztof,

I have updated it in the next patchset.

Thanks,
Ram.> 
>> +    default: 5
>> +    description:
>> +      Restricts the maximum HS gear used in both TX and RX directions.
>> +
>> +  limit-rate:
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    enum: [Rate-A, Rate-B]
> 
> lowercase
I have updated it in the next patchset.

Thanks,
Ram.> 
>> +    default: Rate-B
> 
> 
> Best regards,
> Krzysztof