[PATCH v6 1/9] dt-bindings: mmc: spacemit,sdhci: add pinctrl support for voltage switching

[Iker Pedrosa <ikerpedrosam@gmail.com>]

Document pinctrl properties to support voltage-dependent pin
configuration switching for UHS-I SD card modes.

Add optional pinctrl-names property with two states:
- "default": For 3.3V operation with standard drive strength
- "state_uhs": For 1.8V operation with optimized drive strength

These pinctrl states allow the SDHCI driver to coordinate voltage
switching with pin configuration changes, ensuring proper signal
integrity during UHS-I mode transitions.

Signed-off-by: Iker Pedrosa <ikerpedrosam@gmail.com>
---
 .../devicetree/bindings/mmc/spacemit,sdhci.yaml          | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
index 9a055d963a7f0cdba4741c1e3e7269688dcd5f45..932fccc609bf8dbaf3ecfe09d9e610852ac7afa0 100644
--- a/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/spacemit,sdhci.yaml
@@ -11,6 +11,7 @@ maintainers:
 
 allOf:
   - $ref: mmc-controller.yaml#
+  - $ref: sdhci-common.yaml#
 
 properties:
   compatible:
@@ -44,6 +45,18 @@ properties:
       - const: axi
       - const: sdh
 
+  pinctrl-names:
+    minItems: 1
+    items:
+      - const: default
+      - const: uhs
+
+  pinctrl-0:
+    description: Default pinctrl state for 3.3V operation
+
+  pinctrl-1:
+    description: Optional pinctrl state for 1.8V UHS operation with "uhs" name
+
 required:
   - compatible
   - reg
@@ -62,4 +75,7 @@ examples:
       interrupt-parent = <&plic>;
       clocks = <&clk_apmu 10>, <&clk_apmu 13>;
       clock-names = "core", "io";
+      pinctrl-names = "default", "uhs";
+      pinctrl-0 = <&sdhci_default_cfg>;
+      pinctrl-1 = <&sdhci_uhs_cfg>;
     };

-- 
2.53.0