On Wed, Sep 03, 2025 at 01:34:02PM +0530, 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@xxxxxxxxxxx> > --- > .../devicetree/bindings/mmc/mmc-controller-common.yaml | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml > index 9a7235439759..d6b785cb2bd9 100644 > --- a/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml > +++ b/Documentation/devicetree/bindings/mmc/mmc-controller-common.yaml > @@ -93,6 +93,14 @@ properties: > minimum: 400000 > maximum: 384000000 > > + max-sd-hs-hz: > + 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. > + default: 50000000 Why doesn't max-frequency work for you? I would think frequency limits wouldn't really depend on the mode. > + > disable-wp: > $ref: /schemas/types.yaml#/definitions/flag > description: > -- > 2.34.1 >
