dt-bindings: qcom: document preferred compatible naming

Compatibles can come in two formats.  Either "vendor,ip-soc" or
"vendor,soc-ip".  Qualcomm bindings were mixing both of usages, so add a
DT schema file documenting preferred policy and enforcing it for all new
compatibles, except few existing patterns.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Link: https://lore.kernel.org/r/20220928152501.490840-1-krzysztof.kozlowski@linaro.org

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

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/arm/qcom-soc.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm SoC compatibles naming convention
+
+maintainers:
+  - Bjorn Andersson <andersson@kernel.org>
+
+description: |
+  Guidelines for new compatibles for SoC blocks/components.
+  When adding new compatibles in new bindings, use the format::
+    qcom,SoC-IP
+
+  For example::
+   qcom,sdm845-llcc-bwmon
+
+  When adding new compatibles to existing bindings, use the format in the
+  existing binding, even if it contradicts the above.
+
+select:
+  properties:
+    compatible:
+      pattern: "^qcom,.*(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+  required:
+    - compatible
+
+properties:
+  compatible:
+    oneOf:
+      # Preferred naming style for compatibles of SoC components:
+      - pattern: "^qcom,(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+-.*$"
+      - pattern: "^qcom,(sa|sc)8[0-9]+[a-z][a-z]?-.*$"
+
+      # Legacy namings - variations of existing patterns/compatibles are OK,
+      # but do not add completely new entries to these:
+      - pattern: "^qcom,[ak]pss-wdt-(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+      - pattern: "^qcom,gcc-(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+      - pattern: "^qcom,mmcc-(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+      - pattern: "^qcom,pcie-(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+      - pattern: "^qcom,rpm-(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+      - pattern: "^qcom,scm-(apq|ipq|mdm|msm|qcm|qcs|sa|sc|sdm|sdx|sm)[0-9]+.*$"
+      - enum:
+          - qcom,gpucc-sdm630
+          - qcom,gpucc-sdm660
+          - qcom,lcc-apq8064
+          - qcom,lcc-ipq8064
+          - qcom,lcc-mdm9615
+          - qcom,lcc-msm8960
+          - qcom,lpass-cpu-apq8016
+          - qcom,usb-ss-ipq4019-phy
+          - qcom,usb-hs-ipq4019-phy
+          - qcom,vqmmc-ipq4019-regulator
+
+      # Legacy compatibles with wild-cards - list cannot grow with new bindings:
+      - enum:
+          - qcom,ipq806x-gmac
+          - qcom,ipq806x-nand
+          - qcom,ipq806x-sata-phy
+          - qcom,ipq806x-usb-phy-ss
+          - qcom,ipq806x-usb-phy-hs
+
+additionalProperties: true