Add device tree schema for the Realtek RTL9300 switches. The RTL9300
family is made up of the RTL9301, RTL9302B, RTL9302C and RTL9303. These
have the same SoC differ in the Ethernet switch/SERDES arrangement.

Currently the only supported features are the syscon-reboot and i2c
controllers. The syscon-reboot is needed to be able to reboot the board.
The I2C controllers are slightly unusual because they each own an SCL
pin (GPIO8 for the first controller, GPIO 17 for the second) but have 8
common SDA pins which can be assigned to either controller (but not
both).

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---

Notes:
    Changes in v8:
    - Add r-by from Krzysztof
    - At Lee's request I've separated the i2c binding into a separate patch.
      This one still has a $ref to it so technically the i2c one needs to go
      first but they'll be coming in via different trees so they may not
      arrive in that order.
    Changes in v7:
    - Set additionalProperties: false
    - Remove extraneous examples from i2c binding
    Changes in v6:
    - Drop wildcard compatible
    - Add specific compatibles for the 4 known SoC variants
    - For the i2c part of the binding accept realtek,rtl9301 as a fallback
      for the other compatibles
    - The overall switches will eventually differ because these will have
      different SERDES/port arrangements so they aren't getting the same
      fallback treatment
    Changes in v5:
      I've combined the two series I had in flight so this is the
      combination of adding the switch syscon, the reboot and i2c. It makes
      the changelog a bit meaningless so I've dropped the earlier
      commentary.
    
      As requested I've put a more complete example in the main
      rtl9300-switch.yaml.
    
      I've kept rtl9300-i2c.yaml separate for now but link to it with a $ref
      from rtl9300-switch.yaml to reduce clutter. The example in
      rtl9300-i2c.yaml is technically duplicating part of the example from
      rtl9300-switch.yaml but I feel it's nice to be able to see the example
      next to where the properties are defined.

 .../bindings/mfd/realtek,rtl9301-switch.yaml  | 114 ++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/realtek,rtl9301-switch.yaml

diff --git a/Documentation/devicetree/bindings/mfd/realtek,rtl9301-switch.yaml b/Documentation/devicetree/bindings/mfd/realtek,rtl9301-switch.yaml
new file mode 100644
index 000000000000..f053303ab1e6
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/realtek,rtl9301-switch.yaml
@@ -0,0 +1,114 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/realtek,rtl9301-switch.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Realtek Switch with Internal CPU
+
+maintainers:
+  - Chris Packham <chris.packham@alliedtelesis.co.nz>
+
+description:
+  The RTL9300 is a series of is an Ethernet switches with an integrated CPU. A
+  number of different peripherals are accessed through a common register block,
+  represented here as a syscon node.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - realtek,rtl9301-switch
+          - realtek,rtl9302b-switch
+          - realtek,rtl9302c-switch
+          - realtek,rtl9303-switch
+      - const: syscon
+      - const: simple-mfd
+
+  reg:
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 1
+
+patternProperties:
+  'reboot@[0-9a-f]+$':
+    $ref: /schemas/power/reset/syscon-reboot.yaml#
+
+  'i2c@[0-9a-f]+$':
+    $ref: /schemas/i2c/realtek,rtl9301-i2c.yaml#
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    ethernet-switch@1b000000 {
+      compatible = "realtek,rtl9301-switch", "syscon", "simple-mfd";
+      reg = <0x1b000000 0x10000>;
+      #address-cells = <1>;
+      #size-cells = <1>;
+
+      reboot@c {
+        compatible = "syscon-reboot";
+        reg = <0x0c 0x4>;
+        value = <0x01>;
+      };
+
+      i2c@36c {
+        compatible = "realtek,rtl9301-i2c";
+        reg = <0x36c 0x14>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        i2c@0 {
+          reg = <0>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+          gpio@20 {
+            compatible = "nxp,pca9555";
+            gpio-controller;
+            #gpio-cells = <2>;
+            reg = <0x20>;
+          };
+        };
+
+        i2c@2 {
+          reg = <2>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+          gpio@20 {
+            compatible = "nxp,pca9555";
+            gpio-controller;
+            #gpio-cells = <2>;
+            reg = <0x20>;
+          };
+        };
+      };
+
+      i2c@388 {
+        compatible = "realtek,rtl9301-i2c";
+        reg = <0x388 0x14>;
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        i2c@7 {
+          reg = <7>;
+          #address-cells = <1>;
+          #size-cells = <0>;
+          gpio@20 {
+            compatible = "nxp,pca9555";
+            gpio-controller;
+            #gpio-cells = <2>;
+            reg = <0x20>;
+          };
+        };
+      };
+    };
+
-- 
2.47.0

On Fri, 01 Nov 2024 09:03:47 +1300, Chris Packham wrote:
> Add device tree schema for the Realtek RTL9300 switches. The RTL9300
> family is made up of the RTL9301, RTL9302B, RTL9302C and RTL9303. These
> have the same SoC differ in the Ethernet switch/SERDES arrangement.
> 
> Currently the only supported features are the syscon-reboot and i2c
> controllers. The syscon-reboot is needed to be able to reboot the board.
> The I2C controllers are slightly unusual because they each own an SCL
> pin (GPIO8 for the first controller, GPIO 17 for the second) but have 8
> common SDA pins which can be assigned to either controller (but not
> both).
> 
> [...]

Applied, thanks!

[4/7] dt-bindings: mfd: Add Realtek RTL9300 switch peripherals
      commit: 0c64e7496717779ff60249d5aafd5c18aceee982

--
Lee Jones [李琼斯]