[PATCH v3 1/4] dt-bindings: usb: dwc3: add reference clock period

[Baruch Siach <baruch@xxxxxxxxxx>]

Document the snps,ref-clock-period-ns property that describes reference
clock period when it deviates from the default set value.

Signed-off-by: Baruch Siach <baruch@xxxxxxxxxx>
---
v2:

Address comments from Rob Herring:

  Use standard unit suffix

  Reword description
---
 Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
index 41416fbd92aa..413ac37c447f 100644
--- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
+++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
@@ -252,6 +252,14 @@ properties:
     minimum: 0
     maximum: 0x3f
 
+  snps,ref-clock-period-ns:
+    description:
+      Value for REFCLKPER field of GUCTL register for reference clock period in
+      nanoseconds, when the hardware set default does not match the actual
+      clock.
+    minimum: 1
+    maximum: 0x3ff
+
   snps,rx-thr-num-pkt-prd:
     description:
       Periodic ESS RX packet threshold count (host mode only). Set this and
-- 
2.33.0