[RFC PATCH 3/7] dt-bindings: i3c: nxp,p3h2840: add clock-frequency for SMBus target ports

[Lakshay Piplani]

The SMBus Controller Agent selects the bus speed per transaction through
the transaction descriptor, and supports four discrete rates: 100 kHz,
200 kHz, 400 kHz and 1 MHz.

Describe the standard 'clock-frequency' property for the smbus@ target
port nodes so the rate can be specified per port. The property is already
available through the i2c-controller.yaml reference; restrict it to the
four rates the hardware implements so an unsupported value is rejected at
build time rather than being silently rounded. Target ports default to
400 kHz when the property is absent.

Signed-off-by: Lakshay Piplani <lakshay.piplani at nxp.com>
Signed-off-by: Aman Kumar Pandey <aman.kumarpandey at nxp.com>
Signed-off-by: Vikash Bansal <vikash.bansal at nxp.com>
---
 .../devicetree/bindings/i3c/nxp,p3h2840.yaml          | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/i3c/nxp,p3h2840.yaml b/Documentation/devicetree/bindings/i3c/nxp,p3h2840.yaml
index 09508a7bcbeb..66f9e2b982b1 100644
--- a/Documentation/devicetree/bindings/i3c/nxp,p3h2840.yaml
+++ b/Documentation/devicetree/bindings/i3c/nxp,p3h2840.yaml
@@ -168,6 +168,14 @@ patternProperties:
         description:
           Enables the on-die pull-up for Target Port.
 
+      clock-frequency:
+        enum: [100000, 200000, 400000, 1000000]
+        default: 400000
+        description:
+          SMBus clock rate for this Target Port. The SMBus Controller Agent
+          supports four discrete speeds, selected per transaction. When this
+          property is absent the Target Port runs at 400 kHz.
+
     required:
       - reg
 
@@ -248,6 +256,7 @@ examples:
                 reg = <0x0>;
                 #address-cells = <1>;
                 #size-cells = <0>;
+                clock-frequency = <400000>;
                 nxp,pullup-enable;
             };
 
@@ -255,6 +264,7 @@ examples:
                 reg = <0x1>;
                 #address-cells = <1>;
                 #size-cells = <0>;
+                clock-frequency = <100000>;
                 nxp,pullup-enable;
             };
 
@@ -317,6 +327,7 @@ examples:
                 reg = <0x0>;
                 #address-cells = <1>;
                 #size-cells = <0>;
+                clock-frequency = <1000000>;
                 nxp,pullup-enable;
             };
 
-- 
2.25.1