dt-bindings: samsung: document preferred compatible naming

Compatibles can come in two formats.  Either "vendor,ip-soc" or
"vendor,soc-ip".  Add a DT schema documenting preferred policy and
enforcing it for all new compatibles, except few existing patterns.  The
schema also disallows wild-cards used in SoC compatibles.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220705161340.493474-1-krzysztof.kozlowski@linaro.org

Documentation/devicetree/bindings/arm/samsung/samsung-soc.yaml

@@ -0,0 +1,40 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/samsung/samsung-soc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung S3C, S5P and Exynos SoC compatibles naming convention
+
+maintainers:
+  - Krzysztof Kozlowski <krzk@kernel.org>
+
+description: |
+  Guidelines for new compatibles for SoC blocks/components.
+  When adding new compatibles in new bindings, use the format::
+    samsung,SoC-IP
+
+  For example::
+    samsung,exynos5433-cmu-isp
+
+select:
+  properties:
+    compatible:
+      pattern: "^samsung,.*(s3c|s5pv|exynos)[0-9a-z]+.*$"
+  required:
+    - compatible
+
+properties:
+  compatible:
+    oneOf:
+      - description: Preferred naming style for compatibles of SoC components
+        pattern: "^samsung,(s3c|s5pv|exynos|exynosautov)[0-9]+-.*$"
+
+      # Legacy compatibles with wild-cards - list cannot grow with new bindings:
+      - enum:
+          - samsung,exynos4x12-pinctrl
+          - samsung,exynos4x12-usb2-phy
+          - samsung,s3c64xx-pinctrl
+          - samsung,s3c64xx-wakeup-eint
+
+additionalProperties: true