dt-bindings: clock: Add bindings for Exynos850 CMU_CMGP

CMU_CMGP generates USI and ADC clocks for BLK_ALIVE. In particular USI
clocks are needed for HSI2C_3 and HSI2C_4 instances.

Add clock indices and bindings documentation for CMU_CMGP domain.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Link: https://lore.kernel.org/r/20211121232741.6967-4-semen.protsenko@linaro.org

Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml

@@ -33,6 +33,7 @@ properties:
     enum:
       - samsung,exynos850-cmu-top
       - samsung,exynos850-cmu-apm
+      - samsung,exynos850-cmu-cmgp
       - samsung,exynos850-cmu-core
       - samsung,exynos850-cmu-dpu
       - samsung,exynos850-cmu-hsi
@@ -87,6 +88,24 @@ allOf:
             - const: oscclk
             - const: dout_clkcmu_apm_bus
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: samsung,exynos850-cmu-cmgp
+
+    then:
+      properties:
+        clocks:
+          items:
+            - description: External reference clock (26 MHz)
+            - description: CMU_CMGP bus clock (from CMU_APM)
+
+        clock-names:
+          items:
+            - const: oscclk
+            - const: gout_clkcmu_cmgp_bus
+
   - if:
       properties:
         compatible:

include/dt-bindings/clock/exynos850.h

@@ -84,6 +84,23 @@
 #define CLK_GOUT_SPEEDY_PCLK		21
 #define APM_NR_CLK			22
 
+/* CMU_CMGP */
+#define CLK_RCO_CMGP			1
+#define CLK_MOUT_CMGP_ADC		2
+#define CLK_MOUT_CMGP_USI0		3
+#define CLK_MOUT_CMGP_USI1		4
+#define CLK_DOUT_CMGP_ADC		5
+#define CLK_DOUT_CMGP_USI0		6
+#define CLK_DOUT_CMGP_USI1		7
+#define CLK_GOUT_CMGP_ADC_S0_PCLK	8
+#define CLK_GOUT_CMGP_ADC_S1_PCLK	9
+#define CLK_GOUT_CMGP_GPIO_PCLK		10
+#define CLK_GOUT_CMGP_USI0_IPCLK	11
+#define CLK_GOUT_CMGP_USI0_PCLK		12
+#define CLK_GOUT_CMGP_USI1_IPCLK	13
+#define CLK_GOUT_CMGP_USI1_PCLK		14
+#define CMGP_NR_CLK			15
+
 /* CMU_HSI */
 #define CLK_MOUT_HSI_BUS_USER		1
 #define CLK_MOUT_HSI_MMC_CARD_USER	2