[PATCH v3 1/3] dt-bindings: mmc: sdhci-am654: Add ti,suppress-v1p8-ena

Judith Mendez jm at ti.com
Tue Apr 22 13:44:11 PDT 2025


Some Microcenter/Patriot SD cards and Kingston eMMC are failing init
across Sitara K3 boards. Init failure is due to the sequence when
V1P8_SIGNAL_ENA is set. The V1P8_SIGNAL_ENA has a timing component tied
to it where if set, switch to full-cycle timing happens. The failing
cards do not like change to full-cycle timing before changing bus
width, so add flag to sdhci-am654 binding to suppress V1P8_SIGNAL_ENA
before changing bus width. The switch to full-cycle timing should happen
with HIGH_SPEED_ENA after change of bus width.

Signed-off-by: Judith Mendez <jm at ti.com>
---
 Documentation/devicetree/bindings/mmc/sdhci-am654.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-am654.yaml b/Documentation/devicetree/bindings/mmc/sdhci-am654.yaml
index 676a74695389..0f92bbf8e13b 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-am654.yaml
+++ b/Documentation/devicetree/bindings/mmc/sdhci-am654.yaml
@@ -201,6 +201,11 @@ properties:
       and the controller is required to be forced into Test mode
       to set the TESTCD bit.
 
+  ti,suppress-v1p8-ena:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      When present, V1P8_SIGNAL_ENA shall be suppressed.
+
 required:
   - compatible
   - reg
-- 
2.49.0




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