dt-bindings: clock: add clock definitions and documentation for exynos7870 CMU

Add unique identifiers for exynos7870 clocks for every bank. It adds all
clocks of CMU_MIF, CMU_DISPAUD, CMU_G3D, CMU_ISP, CMU_MFCMSCL, and
CMU_PERI. Document the devicetree bindings as well.

Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250301-exynos7870-pmu-clocks-v5-1-715b646d5206@disroot.org
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Author: Kaustabh Chakraborty

Documentation/devicetree/bindings/clock/samsung,exynos7870-cmu.yaml

@@ -0,0 +1,227 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/samsung,exynos7870-cmu.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos7870 SoC clock controller
+
+maintainers:
+  - Kaustabh Chakraborty <kauschluss@disroot.org>
+
+description: |
+  Exynos7870 clock controller is comprised of several CMU units, generating
+  clocks for different domains. Those CMU units are modeled as separate device
+  tree nodes, and might depend on each other. The root clock in that root tree
+  is an external clock: OSCCLK (26 MHz). This external clock must be defined
+  as a fixed-rate clock in dts.
+
+  Each clock is assigned an identifier and client nodes can use this identifier
+  to specify the clock which they consume. All clocks available for usage
+  in clock consumer nodes are defined as preprocessor macros in
+  include/dt-bindings/clock/samsung,exynos7870-cmu.h header.
+
+properties:
+  compatible:
+    enum:
+      - samsung,exynos7870-cmu-mif
+      - samsung,exynos7870-cmu-dispaud
+      - samsung,exynos7870-cmu-fsys
+      - samsung,exynos7870-cmu-g3d
+      - samsung,exynos7870-cmu-isp
+      - samsung,exynos7870-cmu-mfcmscl
+      - samsung,exynos7870-cmu-peri
+
+  clocks:
+    minItems: 1
+    maxItems: 10
+
+  clock-names:
+    minItems: 1
+    maxItems: 10
+
+  "#clock-cells":
+    const: 1
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - clocks
+  - clock-names
+  - "#clock-cells"
+  - reg
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-mif
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+
+        clock-names:
+          items:
+            - const: oscclk
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-dispaud
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: CMU_DISPAUD bus clock (from CMU_MIF)
+            - description: DECON external clock (from CMU_MIF)
+            - description: DECON vertical clock (from CMU_MIF)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: bus
+            - const: decon_eclk
+            - const: decon_vclk
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-fsys
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: CMU_FSYS bus clock (from CMU_MIF)
+            - description: USB20DRD clock (from CMU_MIF)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: bus
+            - const: usb20drd
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-g3d
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: G3D switch clock (from CMU_MIF)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: switch
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-isp
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: ISP camera clock (from CMU_MIF)
+            - description: ISP clock (from CMU_MIF)
+            - description: ISP VRA clock (from CMU_MIF)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: cam
+            - const: isp
+            - const: vra
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-mfcmscl
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: MSCL clock (from CMU_MIF)
+            - description: MFC clock (from CMU_MIF)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: mfc
+            - const: mscl
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos7870-cmu-peri
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: CMU_PERI bus clock (from CMU_MIF)
+            - description: SPI0 clock (from CMU_MIF)
+            - description: SPI1 clock (from CMU_MIF)
+            - description: SPI2 clock (from CMU_MIF)
+            - description: SPI3 clock (from CMU_MIF)
+            - description: SPI4 clock (from CMU_MIF)
+            - description: UART0 clock (from CMU_MIF)
+            - description: UART1 clock (from CMU_MIF)
+            - description: UART2 clock (from CMU_MIF)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: bus
+            - const: spi0
+            - const: spi1
+            - const: spi2
+            - const: spi3
+            - const: spi4
+            - const: uart0
+            - const: uart1
+            - const: uart2
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/samsung,exynos7870-cmu.h>
+
+    cmu_peri: clock-controller@101f0000 {
+      compatible = "samsung,exynos7870-cmu-peri";
+      reg = <0x101f0000 0x1000>;
+      #clock-cells = <1>;
+
+      clock-names = "oscclk", "bus", "spi0", "spi1", "spi2",
+                    "spi3", "spi4", "uart0", "uart1", "uart2";
+      clocks = <&oscclk>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_BUS>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_SPI0>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_SPI1>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_SPI2>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_SPI3>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_SPI4>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_UART0>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_UART1>,
+               <&cmu_mif CLK_GOUT_MIF_CMU_PERI_UART2>;
+    };
+
+...