From 2c0594f9f0629a8b4d46e7e1bd069a0bafc2e350 Mon Sep 17 00:00:00 2001
From: Alex Elder <elder@riscstar.com>
Date: Wed, 9 Apr 2025 14:22:11 -0500
Subject: [PATCH] dt-bindings: serial: 8250: support an optional second clock

The SpacemiT UART driver requires a bus clock to be enabled in addition
to the primary function clock.  Add the option to specify two clocks
for an 8250-compatible UART, named "core" and "bus".  If both are needed,
require them to be named.

Signed-off-by: Alex Elder <elder@riscstar.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://lore.kernel.org/r/20250409192213.1130181-2-elder@riscstar.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 .../devicetree/bindings/serial/8250.yaml      | 30 ++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/serial/8250.yaml b/Documentation/devicetree/bindings/serial/8250.yaml
index dc0d52920575..33d2016b6509 100644
--- a/Documentation/devicetree/bindings/serial/8250.yaml
+++ b/Documentation/devicetree/bindings/serial/8250.yaml
@@ -135,7 +135,16 @@ properties:
   clock-frequency: true
 
   clocks:
-    maxItems: 1
+    minItems: 1
+    items:
+      - description: The core function clock
+      - description: An optional bus clock
+
+  clock-names:
+    minItems: 1
+    items:
+      - const: core
+      - const: bus
 
   resets:
     maxItems: 1
@@ -224,6 +233,25 @@ required:
   - reg
   - interrupts
 
+if:
+  properties:
+    compatible:
+      contains:
+        const: spacemit,k1-uart
+then:
+  required: [clock-names]
+  properties:
+    clocks:
+      minItems: 2
+    clock-names:
+      minItems: 2
+else:
+  properties:
+    clocks:
+      maxItems: 1
+    clock-names:
+      maxItems: 1
+
 unevaluatedProperties: false
 
 examples: