HS400 requires a data strobe line in addition to the other MMC signal lines, so if a board design neglects to wire up this signal, HS400 mode is no available, even if both the controller and the eMMC are claiming to support this mode. Add a DT flag to allow boards to disable the HS400 support in this case. Signed-off-by: Lucas Stach <dev@xxxxxxxxxx> --- Documentation/devicetree/bindings/mmc/mmc-controller.yaml | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml index e141330c1114..ac80d09df3a9 100644 --- a/Documentation/devicetree/bindings/mmc/mmc-controller.yaml +++ b/Documentation/devicetree/bindings/mmc/mmc-controller.yaml @@ -220,6 +220,11 @@ properties: description: eMMC HS400 enhanced strobe mode is supported + no-mmc-hs400: + $ref: /schemas/types.yaml#/definitions/flag + description: + All eMMC HS400 modes are not supported. + dsr: description: Value the card Driver Stage Register (DSR) should be programmed -- 2.31.1