[PATCH v3 5/6] dt-bindings: mmc: renesas,sdhi: Add mux-states property

Josua Mayer
2025-12-10T17:39:25Z

Add mux controller support for data or control lines that are muxed
between a host and multiple cards.

There are several devices supporting a choice of eMMC or SD on a single
board by both dip switch and gpio, e.g. Renesas RZ/G2L SMARC SoM and
SolidRun RZ/G2L SoM.

In-tree dts for the Renesas boards currently rely on preprocessor macros
and gpio hogs to describe the respective cards.

By adding mux-states property to sdhi controller description, boards can
correctly describe the mux that already exists in hardware - and drivers
can coordinate between mux selection and probing for cards.

Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Josua Mayer <josua@solid-run.com>
---
Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml b/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
index c754ea71f51f7..64fac0d11329a 100644
--- a/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
+++ b/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
@@ -106,6 +106,11 @@ properties:
iommus:
maxItems: 1

+ mux-states:
+ description:
+ mux controller node to route the SD/SDIO/eMMC signals from SoC to cards.
+ maxItems: 1
+
power-domains:
maxItems: 1

@@ -275,6 +280,7 @@ examples:
max-frequency = <195000000>;
power-domains = <&sysc R8A7790_PD_ALWAYS_ON>;
resets = <&cpg 314>;
+ mux-states = <&mux 0>;
};

sdhi1: mmc@ee120000 {

--
2.51.0