[PATCH V3 2/4] dt-bindings: mmc: controller: Add max-sd-hs-frequency property
From: Sarthak Garg
Date: Wed Jun 18 2025 - 03:29:28 EST
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.
This property is useful for platforms with vendor-specific hardware
constraints, such as the presence of a level shifter that cannot
reliably support the default 50 MHz HS frequency. It allows the host
driver to cap the HS mode frequency accordingly.
Signed-off-by: Sarthak Garg <quic_sartgarg@xxxxxxxxxxx>
---
.../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..1976f5f8c401 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 platforms with vendor-specific
+ limitations, such as the presence of a level shifter that cannot support
+ the default 50 MHz HS frequency or other.
+ minimum: 400000
+ maximum: 50000000
+
disable-wp:
$ref: /schemas/types.yaml#/definitions/flag
description:
--
2.34.1