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

Judith Mendez
2025-04-22T22:05:28Z

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@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