Merge tag 'devfreq-next-for-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux

Pull devfreq updates for v5.20 from Chanwoo Choi:

"1. Add new Mediatek CCI (Cache Coherent Interconnect) devfreq driver

    - Add new MediaTek Cache Coherent Interconnect (CCI) devfreq drviver
      which supports the dynamic voltage and clock scaling.

      This driver uses the passive devfreq governor to get target
      frequencies and adjust voltages because it depends on MediaTek
      CPU frequency driver. In MT8183 and MT8186, the MediaTek CCI is
      supplied by the same regulators with the little core CPUs.

 2. Update devfreq drivers

    - Convert the Samsung Exynos SoC Bus bindings to DT schema of
      exynos-bus.c.

    - Remove kernel-doc warnings by adding the description for unused
      fucntion parameters on devfreq core.

    - Use NULL to pass a null pointer rather than zero according to
      function propotype on imx-bus.c.

    - Print error message instead of error interger value on
      tegra30-devfreq.c."

* tag 'devfreq-next-for-5.20' of git://git.kernel.org/pub/scm/linux/kernel/git/chanwoo/linux:
  PM / devfreq: tegra30: Add error message for devm_devfreq_add_device()
  PM / devfreq: imx-bus: use NULL to pass a null pointer rather than zero
  PM / devfreq: shut up kernel-doc warnings
  dt-bindings: interconnect: samsung,exynos-bus: convert to dtschema
  PM / devfreq: mediatek: Introduce MediaTek CCI devfreq driver
  dt-bindings: interconnect: Add MediaTek CCI dt-bindings

Author: rafaeljw

Documentation/devicetree/bindings/devfreq/exynos-bus.txt

@@ -0,0 +1,141 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interconnect/mediatek,cci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek Cache Coherent Interconnect (CCI) frequency and voltage scaling
+
+maintainers:
+  - Jia-Wei Chang <[email protected]>
+  - Johnson Wang <[email protected]>
+
+description: |
+  MediaTek Cache Coherent Interconnect (CCI) is a hardware engine used by
+  MT8183 and MT8186 SoCs to scale the frequency and adjust the voltage in
+  hardware. It can also optimize the voltage to reduce the power consumption.
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt8183-cci
+      - mediatek,mt8186-cci
+
+  clocks:
+    items:
+      - description:
+          The multiplexer for clock input of the bus.
+      - description:
+          A parent of "bus" clock which is used as an intermediate clock source
+          when the original clock source (PLL) is under transition and not
+          stable yet.
+
+  clock-names:
+    items:
+      - const: cci
+      - const: intermediate
+
+  operating-points-v2: true
+  opp-table: true
+
+  proc-supply:
+    description:
+      Phandle of the regulator for CCI that provides the supply voltage.
+
+  sram-supply:
+    description:
+      Phandle of the regulator for sram of CCI that provides the supply
+      voltage. When it is present, the implementation needs to do
+      "voltage tracking" to step by step scale up/down Vproc and Vsram to fit
+      SoC specific needs. When absent, the voltage scaling flow is handled by
+      hardware, hence no software "voltage tracking" is needed.
+
+required:
+  - compatible
+  - clocks
+  - clock-names
+  - operating-points-v2
+  - proc-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/mt8183-clk.h>
+    cci: cci {
+        compatible = "mediatek,mt8183-cci";
+        clocks = <&mcucfg CLK_MCU_BUS_SEL>,
+                 <&topckgen CLK_TOP_ARMPLL_DIV_PLL1>;
+        clock-names = "cci", "intermediate";
+        operating-points-v2 = <&cci_opp>;
+        proc-supply = <&mt6358_vproc12_reg>;
+    };
+
+    cci_opp: opp-table-cci {
+        compatible = "operating-points-v2";
+        opp-shared;
+        opp2_00: opp-273000000 {
+            opp-hz = /bits/ 64 <273000000>;
+            opp-microvolt = <650000>;
+        };
+        opp2_01: opp-338000000 {
+            opp-hz = /bits/ 64 <338000000>;
+            opp-microvolt = <687500>;
+        };
+        opp2_02: opp-403000000 {
+            opp-hz = /bits/ 64 <403000000>;
+            opp-microvolt = <718750>;
+        };
+        opp2_03: opp-463000000 {
+            opp-hz = /bits/ 64 <463000000>;
+            opp-microvolt = <756250>;
+        };
+        opp2_04: opp-546000000 {
+            opp-hz = /bits/ 64 <546000000>;
+            opp-microvolt = <800000>;
+        };
+        opp2_05: opp-624000000 {
+            opp-hz = /bits/ 64 <624000000>;
+            opp-microvolt = <818750>;
+        };
+        opp2_06: opp-689000000 {
+            opp-hz = /bits/ 64 <689000000>;
+            opp-microvolt = <850000>;
+        };
+        opp2_07: opp-767000000 {
+            opp-hz = /bits/ 64 <767000000>;
+            opp-microvolt = <868750>;
+        };
+        opp2_08: opp-845000000 {
+            opp-hz = /bits/ 64 <845000000>;
+            opp-microvolt = <893750>;
+        };
+        opp2_09: opp-871000000 {
+            opp-hz = /bits/ 64 <871000000>;
+            opp-microvolt = <906250>;
+        };
+        opp2_10: opp-923000000 {
+            opp-hz = /bits/ 64 <923000000>;
+            opp-microvolt = <931250>;
+        };
+        opp2_11: opp-962000000 {
+            opp-hz = /bits/ 64 <962000000>;
+            opp-microvolt = <943750>;
+        };
+        opp2_12: opp-1027000000 {
+            opp-hz = /bits/ 64 <1027000000>;
+            opp-microvolt = <975000>;
+        };
+        opp2_13: opp-1092000000 {
+            opp-hz = /bits/ 64 <1092000000>;
+            opp-microvolt = <1000000>;
+        };
+        opp2_14: opp-1144000000 {
+            opp-hz = /bits/ 64 <1144000000>;
+            opp-microvolt = <1025000>;
+        };
+        opp2_15: opp-1196000000 {
+            opp-hz = /bits/ 64 <1196000000>;
+            opp-microvolt = <1050000>;
+        };
+    };