[PATCH v9 04/16] dt-bindings: imx6q-pcie: Add linux,pci-domain as required for iMX8MQ

[Frank Li <Frank.Li@nxp.com>]

iMX8MQ have two pci controllers. Adds "linux,pci-domain" as required
property for iMX8MQ to indicate pci controller index.

This adjustment paves the way for eliminating the hardcoded check on the
base register for acquiring the controller_id.

	...
	if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
		imx6_pcie->controller_id = 1;
	...

The controller_id is crucial and utilized for certain register bit
positions. It must align precisely with the controller index in the SoC.
An auto-incremented ID don't fit this case. The DTS or fuse configurations
may deactivate specific PCI controllers.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---

Notes:
    Change from v8 to v9
    - Add rob's review tag
    
    Change from v6 to v8
    -none
    
    Change from v5 to v6
    - rework commit message to explain why need required and why auto increase
    id not work
    
    Change from v4 to v5
    - new patch at v5

 .../bindings/pci/fsl,imx6q-pcie-common.yaml           | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml
index d91b639ae7ae7..8f39b4e6e8491 100644
--- a/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml
+++ b/Documentation/devicetree/bindings/pci/fsl,imx6q-pcie-common.yaml
@@ -265,6 +265,17 @@ allOf:
             - const: apps
             - const: turnoff
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - fsl,imx8mq-pcie
+              - fsl,imx8mq-pcie-ep
+    then:
+      required:
+        - linux,pci-domain
+
 additionalProperties: true
 
 ...
-- 
2.34.1