dt-bindings: PCI: mediatek: Update the Device tree bindings

There are two independent PCIe controllers in MT2712 and MT7622
platform. Each of them should contain an independent MSI domain.

In old dts architecture, MSI domain will be inherited from the root
bridge, and all of the devices will share the same MSI domain.
Hence that, the PCIe devices will not work properly if the irq number
which required is more than 32.

Split the PCIe node for MT2712 and MT7622 platform to comply with
the hardware design and fix MSI issue.

Link: https://lore.kernel.org/r/20210823032800.1660-2-chuanjia.liu@mediatek.com
Signed-off-by: Chuanjia Liu <chuanjia.liu@mediatek.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Rob Herring <robh+dt@kernel.org>
Acked-by: Ryder Lee <ryder.lee@mediatek.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/pci/mediatek-pcie-cfg.yaml b/Documentation/devicetree/bindings/pci/mediatek-pcie-cfg.yaml
new file mode 100644
index 000000000000..841a3d284bbf
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/mediatek-pcie-cfg.yaml
@@ -0,0 +1,39 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pci/mediatek-pcie-cfg.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek PCIECFG controller
+
+maintainers:
+  - Chuanjia Liu <chuanjia.liu@mediatek.com>
+  - Jianjun Wang <jianjun.wang@mediatek.com>
+
+description: |
+  The MediaTek PCIECFG controller controls some feature about
+  LTSSM, ASPM and so on.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - mediatek,generic-pciecfg
+      - const: syscon
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    pciecfg: pciecfg@1a140000 {
+        compatible = "mediatek,generic-pciecfg", "syscon";
+        reg = <0x1a140000 0x1000>;
+    };
+...