[PATCH v3 1/7] dt-bindings: pincfg-node: Add input-voltage-microvolt property

[Yu-Chun Lin <eleanor.lin@realtek.com>]

From: Tzuyi Chang <tychang@realtek.com>

Add a generic pin configuration property "input-voltage-microvolt" to
support hardware designs where the input logic threshold is decoupled
from the power supply voltage.

This property allows the pinctrl driver to configure the correct internal
reference voltage for pins that need to accept input signals at a different
voltage level than their power supply. For example, a pin powered by 3.3V
may need to accept 1.8V logic signals.

This defines the reference for VIH (Input High Voltage) and VIL (Input Low
Voltage) thresholds, enabling proper signal detection across different
voltage domains.

Signed-off-by: Tzuyi Chang <tychang@realtek.com>
Co-developed-by: Yu-Chun Lin <eleanor.lin@realtek.com>
Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
---
Changes in v3:
- Rebased onto the devel branch of the pinctrl tree.
- Improved commit message and description.
---
 Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml b/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
index fe936ab09104..fd49a0d53bf0 100644
--- a/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
+++ b/Documentation/devicetree/bindings/pinctrl/pincfg-node.yaml
@@ -162,6 +162,11 @@ properties:
       this affects the expected delay in ps before latching a value to
       an output pin.
 
+  input-voltage-microvolt:
+    description: Specifies the input voltage level of the pin in microvolts.
+      This defines the reference for  VIH (Input High Voltage) and VIL
+      (Input Low Voltage) thresholds for proper signal detection.
+
 allOf:
   - if:
       required:
-- 
2.34.1