dt-bindings: interconnect: samsung,exynos-bus: convert to dtschema

Convert the Samsung Exynos SoC Bus and Interconnect bindings to DT
schema.

Vast parts of descritpion and example were copied, so keep license as
GPL-2.0-only.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

Documentation/devicetree/bindings/interconnect/samsung,exynos-bus.yaml

+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interconnect/samsung,exynos-bus.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Samsung Exynos SoC Bus and Interconnect
+
+maintainers:
+  - Chanwoo Choi <cw00.choi@samsung.com>
+  - Krzysztof Kozlowski <krzk@kernel.org>
+
+description: |
+  The Samsung Exynos SoC has many buses for data transfer between DRAM and
+  sub-blocks in SoC. Most Exynos SoCs share the common architecture for buses.
+  Generally, each bus of Exynos SoC includes a source clock and a power line,
+  which are able to change the clock frequency of the bus in runtime. To
+  monitor the usage of each bus in runtime, the driver uses the PPMU (Platform
+  Performance Monitoring Unit), which is able to measure the current load of
+  sub-blocks.
+
+  The Exynos SoC includes the various sub-blocks which have the each AXI bus.
+  The each AXI bus has the owned source clock but, has not the only owned power
+  line. The power line might be shared among one more sub-blocks.  So, we can
+  divide into two type of device as the role of each sub-block.  There are two
+  type of bus devices as following::
+   - parent bus device
+   - passive bus device
+
+  Basically, parent and passive bus device share the same power line.  The
+  parent bus device can only change the voltage of shared power line and the
+  rest bus devices (passive bus device) depend on the decision of the parent
+  bus device. If there are three blocks which share the VDD_xxx power line,
+  Only one block should be parent device and then the rest blocks should depend
+  on the parent device as passive device.
+
+    VDD_xxx |--- A block (parent)
+      |--- B block (passive)
+      |--- C block (passive)
+
+  There are a little different composition among Exynos SoC because each Exynos
+  SoC has different sub-blocks. Therefore, such difference should be specified
+  in devicetree file instead of each device driver. In result, this driver is
+  able to support the bus frequency for all Exynos SoCs.
+
+  Detailed correlation between sub-blocks and power line according
+  to Exynos SoC::
+   - In case of Exynos3250, there are two power line as following::
+     VDD_MIF |--- DMC (Dynamic Memory Controller)
+
+     VDD_INT |--- LEFTBUS (parent device)
+       |--- PERIL
+       |--- MFC
+       |--- G3D
+       |--- RIGHTBUS
+       |--- PERIR
+       |--- FSYS
+       |--- LCD0
+       |--- PERIR
+       |--- ISP
+       |--- CAM
+
+     - MIF bus's frequency/voltage table
+       -----------------------
+       |Lv| Freq   | Voltage |
+       -----------------------
+       |L1| 50000  |800000   |
+       |L2| 100000 |800000   |
+       |L3| 134000 |800000   |
+       |L4| 200000 |825000   |
+       |L5| 400000 |875000   |
+       -----------------------
+
+     - INT bus's frequency/voltage table
+       ----------------------------------------------------------
+       |Block|LEFTBUS|RIGHTBUS|MCUISP |ISP    |PERIL  ||VDD_INT |
+       | name|       |LCD0    |       |       |       ||        |
+       |     |       |FSYS    |       |       |       ||        |
+       |     |       |MFC     |       |       |       ||        |
+       ----------------------------------------------------------
+       |Mode |*parent|passive |passive|passive|passive||        |
+       ----------------------------------------------------------
+       |Lv   |Frequency                               ||Voltage |
+       ----------------------------------------------------------
+       |L1   |50000  |50000   |50000  |50000  |50000  ||900000  |
+       |L2   |80000  |80000   |80000  |80000  |80000  ||900000  |
+       |L3   |100000 |100000  |100000 |100000 |100000 ||1000000 |
+       |L4   |134000 |134000  |200000 |200000 |       ||1000000 |
+       |L5   |200000 |200000  |400000 |300000 |       ||1000000 |
+       ----------------------------------------------------------
+
+   - In case of Exynos4210, there is one power line as following::
+     VDD_INT |--- DMC (parent device, Dynamic Memory Controller)
+       |--- LEFTBUS
+       |--- PERIL
+       |--- MFC(L)
+       |--- G3D
+       |--- TV
+       |--- LCD0
+       |--- RIGHTBUS
+       |--- PERIR
+       |--- MFC(R)
+       |--- CAM
+       |--- FSYS
+       |--- GPS
+       |--- LCD0
+       |--- LCD1
+
+   - In case of Exynos4x12, there are two power line as following::
+     VDD_MIF |--- DMC (Dynamic Memory Controller)
+
+     VDD_INT |--- LEFTBUS (parent device)
+       |--- PERIL
+       |--- MFC(L)
+       |--- G3D
+       |--- TV
+       |--- IMAGE
+       |--- RIGHTBUS
+       |--- PERIR
+       |--- MFC(R)
+       |--- CAM
+       |--- FSYS
+       |--- GPS
+       |--- LCD0
+       |--- ISP
+
+   - In case of Exynos5422, there are two power line as following::
+     VDD_MIF |--- DREX 0 (parent device, DRAM EXpress controller)
+             |--- DREX 1
+
+     VDD_INT |--- NoC_Core (parent device)
+       |--- G2D
+       |--- G3D
+       |--- DISP1
+       |--- NoC_WCORE
+       |--- GSCL
+       |--- MSCL
+       |--- ISP
+       |--- MFC
+       |--- GEN
+       |--- PERIS
+       |--- PERIC
+       |--- FSYS
+       |--- FSYS2
+
+   - In case of Exynos5433, there is VDD_INT power line as following::
+     VDD_INT |--- G2D (parent device)
+       |--- MSCL
+       |--- GSCL
+       |--- JPEG
+       |--- MFC
+       |--- HEVC
+       |--- BUS0
+       |--- BUS1
+       |--- BUS2
+       |--- PERIS (Fixed clock rate)
+       |--- PERIC (Fixed clock rate)
+       |--- FSYS  (Fixed clock rate)
+
+properties:
+  compatible:
+    enum:
+      - samsung,exynos-bus
+
+  clocks:
+    maxItems: 1
+
+  clock-names:
+    items:
+      - const: bus
+
+  devfreq:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Parent bus device. Valid and required only for the passive bus devices.
+
+  devfreq-events:
+    $ref: /schemas/types.yaml#/definitions/phandle-array
+    minItems: 1
+    maxItems: 4
+    description:
+      Devfreq-event device to monitor the current utilization of buses. Valid
+      and required only for the parent bus devices.
+
+  exynos,saturation-ratio:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Percentage value which is used to calibrate the performance count against
+      total cycle count.  Valid only for the parent bus devices.
+
+  '#interconnect-cells':
+    const: 0
+
+  interconnects:
+    minItems: 1
+    maxItems: 2
+
+  operating-points-v2: true
+
+  samsung,data-clock-ratio:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 8
+    description:
+      Ratio of the data throughput in B/s to minimum data clock frequency in
+      Hz.
+
+  vdd-supply:
+    description:
+      Main bus power rail. Valid and required only for the parent bus devices.
+
+required:
+  - compatible
+  - clocks
+  - clock-names
+  - operating-points-v2
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/exynos3250.h>
+
+    bus-dmc {
+        compatible = "samsung,exynos-bus";
+        clocks = <&cmu_dmc CLK_DIV_DMC>;
+        clock-names = "bus";
+        operating-points-v2 = <&bus_dmc_opp_table>;
+        devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+        vdd-supply = <&buck1_reg>;
+    };
+
+    ppmu_dmc0: ppmu@106a0000 {
+        compatible = "samsung,exynos-ppmu";
+        reg = <0x106a0000 0x2000>;
+        events {
+            ppmu_dmc0_3: ppmu-event3-dmc0 {
+                event-name = "ppmu-event3-dmc0";
+            };
+        };
+    };
+
+    bus_leftbus: bus-leftbus {
+        compatible = "samsung,exynos-bus";
+        clocks = <&cmu CLK_DIV_GDL>;
+        clock-names = "bus";
+        operating-points-v2 = <&bus_leftbus_opp_table>;
+        devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
+        vdd-supply = <&buck3_reg>;
+    };
+
+    bus-rightbus {
+        compatible = "samsung,exynos-bus";
+        clocks = <&cmu CLK_DIV_GDR>;
+        clock-names = "bus";
+        operating-points-v2 = <&bus_leftbus_opp_table>;
+        devfreq = <&bus_leftbus>;
+    };
+
+  - |
+    dmc: bus-dmc {
+        compatible = "samsung,exynos-bus";
+        clocks = <&clock CLK_DIV_DMC>;
+        clock-names = "bus";
+        operating-points-v2 = <&bus_dmc_opp_table>;
+        samsung,data-clock-ratio = <4>;
+        #interconnect-cells = <0>;
+        devfreq-events = <&ppmu_dmc0_3>, <&ppmu_dmc1_3>;
+        vdd-supply = <&buck1_reg>;
+    };
+
+    leftbus: bus-leftbus {
+        compatible = "samsung,exynos-bus";
+        clocks = <&clock CLK_DIV_GDL>;
+        clock-names = "bus";
+        operating-points-v2 = <&bus_leftbus_opp_table>;
+        interconnects = <&dmc>;
+        #interconnect-cells = <0>;
+        devfreq-events = <&ppmu_leftbus_3>, <&ppmu_rightbus_3>;
+        vdd-supply = <&buck3_reg>;
+    };
+
+    display: bus-display {
+        compatible = "samsung,exynos-bus";
+        clocks = <&clock CLK_DIV_ACLK_266>;
+        clock-names = "bus";
+        operating-points-v2 = <&bus_display_opp_table>;
+        interconnects = <&leftbus &dmc>;
+        #interconnect-cells = <0>;
+        devfreq = <&leftbus>;
+    };

MAINTAINERS

@@ -4374,7 +4374,7 @@ L:	linux-pm@vger.kernel.org
 L:	linux-samsung-soc@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux.git
-F:	Documentation/devicetree/bindings/devfreq/exynos-bus.txt
+F:	Documentation/devicetree/bindings/interconnect/samsung,exynos-bus.yaml
 F:	drivers/devfreq/exynos-bus.c
 
 BUSLOGIC SCSI DRIVER