[PATCH V6 1/4] ufs: dt-bindings: Document gear and rate limit properties

Ram Kumar Dwivedi posted 4 patches 2 weeks ago
[PATCH V6 1/4] ufs: dt-bindings: Document gear and rate limit properties
Posted by Ram Kumar Dwivedi 2 weeks ago
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.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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..9f04f34d8c5a 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: 6
+    default: 6
+    description:
+      Restricts the maximum HS gear used in both TX and RX directions.
+
+  limit-gear-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
RE: [PATCH V6 1/4] ufs: dt-bindings: Document gear and rate limit properties
Posted by Alim Akhtar 2 weeks ago

> -----Original Message-----
> From: Ram Kumar Dwivedi <quic_rdwivedi@quicinc.com>
> Sent: Wednesday, September 17, 2025 7:40 PM
> To: alim.akhtar@samsung.com; avri.altman@wdc.com; bvanassche@acm.org;
> robh@kernel.org; krzk+dt@kernel.org; conor+dt@kernel.org; mani@kernel.org;
> James.Bottomley@HansenPartnership.com; martin.petersen@oracle.com
> Cc: linux-scsi@vger.kernel.org; devicetree@vger.kernel.org; linux-
> kernel@vger.kernel.org; linux-arm-msm@vger.kernel.org; Krzysztof Kozlowski
> <krzysztof.kozlowski@linaro.org>
> Subject: [PATCH V6 1/4] ufs: dt-bindings: Document gear and rate limit
> properties
> 
> 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.
> 
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Signed-off-by: Ram Kumar Dwivedi <quic_rdwivedi@quicinc.com>
> ---
Thanks!
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>