i.MX95 PCIes have two reference clock inputs: one from internal PLL.
It's wired inside chip and present as "ref" clock. It's not an optional
clock. The other from off chip crystal oscillator. The "extref" clock
refers to a reference clock from an external crystal oscillator through
the CLKIN_N/P pair PADs. It is an optional clock, relied on the board
design.

Add additional optional external reference clock input for i.MX95 PCIes.

Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
---
 Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml
index ca5f2970f217c..12a01f7a57443 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml
@@ -44,7 +44,7 @@ properties:
 
   clock-names:
     minItems: 3
-    maxItems: 5
+    maxItems: 6
 
   interrupts:
     minItems: 1
@@ -212,14 +212,17 @@ allOf:
     then:
       properties:
         clocks:
-          maxItems: 5
+          minItems: 5
+          maxItems: 6
         clock-names:
+          minItems: 5
           items:
             - const: pcie
             - const: pcie_bus
             - const: pcie_phy
             - const: pcie_aux
             - const: ref
+            - const: extref  # Optional
 
 unevaluatedProperties: false
 
-- 
2.37.1

On Thu, 11 Dec 2025 14:48:19 +0800, Richard Zhu wrote:
> i.MX95 PCIes have two reference clock inputs: one from internal PLL.
> It's wired inside chip and present as "ref" clock. It's not an optional
> clock. The other from off chip crystal oscillator. The "extref" clock
> refers to a reference clock from an external crystal oscillator through
> the CLKIN_N/P pair PADs. It is an optional clock, relied on the board
> design.
> 
> Add additional optional external reference clock input for i.MX95 PCIes.
> 
> Signed-off-by: Richard Zhu <hongxing.zhu@nxp.com>
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> ---
>  Documentation/devicetree/bindings/pci/fsl,imx6q-pcie.yaml | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>