Some platforms may require limiting the maximum frequency used in SD
High-Speed (HS) mode due to board-level hardware constraints. For
example, certain boards may include level shifters or other components
that cannot reliably operate at the default 50 MHz HS frequency.

Introduce a new optional device tree property max-sd-hs-frequency to
limit the maximum frequency (in Hz) used for SD cards operating in
High-Speed (HS) mode.

Signed-off-by: Sarthak Garg <quic_sartgarg@quicinc.com>
---
 .../devicetree/bindings/mmc/mmc-controller-common.yaml | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
index 9a7235439759..6c2529b976d1 100644
--- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
+++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
@@ -93,6 +93,16 @@ properties:
     minimum: 400000
     maximum: 384000000
 
+  max-sd-hs-frequency:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Maximum frequency (in Hz) to be used for SD cards operating in
+      High-Speed (HS) mode. This is useful for board-specific limitations,
+      such as level shifters or others where the card cannot reliably
+      operate at the default 50 MHz HS frequency.
+    minimum: 400000
+    maximum: 50000000
+
   disable-wp:
     $ref: /schemas/types.yaml#/definitions/flag
     description:
-- 
2.34.1

On 01/08/2025 10:45, Sarthak Garg wrote:
> Some platforms may require limiting the maximum frequency used in SD
> High-Speed (HS) mode due to board-level hardware constraints. For
> example, certain boards may include level shifters or other components
> that cannot reliably operate at the default 50 MHz HS frequency.
> 
> Introduce a new optional device tree property max-sd-hs-frequency to
> limit the maximum frequency (in Hz) used for SD cards operating in
> High-Speed (HS) mode.
> 
> Signed-off-by: Sarthak Garg <quic_sartgarg@quicinc.com>
> ---
>  .../devicetree/bindings/mmc/mmc-controller-common.yaml | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> index 9a7235439759..6c2529b976d1 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
> @@ -93,6 +93,16 @@ properties:
>      minimum: 400000
>      maximum: 384000000
>  
> +  max-sd-hs-frequency:

Use standard unit suffixes. s/frequency/hz/



> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Maximum frequency (in Hz) to be used for SD cards operating in
> +      High-Speed (HS) mode. This is useful for board-specific limitations,
> +      such as level shifters or others where the card cannot reliably
> +      operate at the default 50 MHz HS frequency.

Don't repeat constraints in free form text.

default:

On 8/1/2025 2:30 PM, Krzysztof Kozlowski wrote:
> On 01/08/2025 10:45, Sarthak Garg wrote:
>> Some platforms may require limiting the maximum frequency used in SD
>> High-Speed (HS) mode due to board-level hardware constraints. For
>> example, certain boards may include level shifters or other components
>> that cannot reliably operate at the default 50 MHz HS frequency.
>>
>> Introduce a new optional device tree property max-sd-hs-frequency to
>> limit the maximum frequency (in Hz) used for SD cards operating in
>> High-Speed (HS) mode.
>>
>> Signed-off-by: Sarthak Garg <quic_sartgarg@quicinc.com>
>> ---
>>   .../devicetree/bindings/mmc/mmc-controller-common.yaml | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
>> index 9a7235439759..6c2529b976d1 100644
>> --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
>> +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml
>> @@ -93,6 +93,16 @@ properties:
>>       minimum: 400000
>>       maximum: 384000000
>>   
>> +  max-sd-hs-frequency:
> 
> Use standard unit suffixes. s/frequency/hz/
> 
> 
> 

Sure will update this name to max-sd-hs-hz in V5.

>> +    $ref: /schemas/types.yaml#/definitions/uint32
>> +    description: |
>> +      Maximum frequency (in Hz) to be used for SD cards operating in
>> +      High-Speed (HS) mode. This is useful for board-specific limitations,
>> +      such as level shifters or others where the card cannot reliably
>> +      operate at the default 50 MHz HS frequency.
> 
> Don't repeat constraints in free form text.
> 
> default:
> 
> 

Sure will remove min/max constraints and add default: 50000000 in V5.