dt-binding: mfd: Add Richtek RT5120 PMIC support

Add Richtek RT5120 PMIC devicetree document.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/1660100142-32493-2-git-send-email-u0084500@gmail.com

Documentation/devicetree/bindings/mfd/richtek,rt5120.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/richtek,rt5120.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Richtek RT5120 PMIC
+
+maintainers:
+  - ChiYuan Huang <cy_huang@richtek.com>
+
+description: |
+  The RT5120 provides four high-efficiency buck converters and one LDO voltage
+  regulator. The device is targeted at providingthe processor voltage, memory,
+  I/O, and peripheral rails in home entertainment devices. The I2C interface is
+  used for dynamic voltage scaling of the processor voltage, power rails on/off
+  sequence control, operation mode selection.
+
+properties:
+  compatible:
+    enum:
+      - richtek,rt5120
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+
+  wakeup-source: true
+
+  richtek,enable-undervolt-hiccup:
+    type: boolean
+    description: |
+      If used, under voltage protection trigger hiccup behavior, else latchup as
+      default
+
+  richtek,enable-overvolt-hiccup:
+    type: boolean
+    description:
+      Like as 'enable-uv-hiccup', it configures over voltage protection to
+      hiccup, else latchup as default
+
+  vin1-supply:
+    description: phandle for buck1 input power source
+
+  vin2-supply:
+    description: phandle for buck2 input power source
+
+  vin3-supply:
+    description: phandle for buck3 input power source
+
+  vin4-supply:
+    description: phandle for buck4 input power source
+
+  vinldo-supply:
+    description: phandle for ldo input power source
+
+  regulators:
+    type: object
+
+    patternProperties:
+      "^buck[1-4]$":
+        type: object
+        $ref: /schemas/regulator/regulator.yaml#
+        unevaluatedProperties: false
+
+        properties:
+          regulator-allowed-modes:
+            description: |
+              Used to specify the allowed buck converter operating mode
+              mode mapping:
+                0: auto mode
+                1: force pwm mode
+            items:
+              enum: [0, 1]
+
+      "^(ldo|exten)$":
+        type: object
+        $ref: /schemas/regulator/regulator.yaml#
+        unevaluatedProperties: false
+
+    additionalProperties: false
+
+  powerkey:
+    type: object
+    description:
+      PON key that connected to RT5120 PMIC.
+
+    properties:
+      compatible:
+        enum:
+          - richtek,rt5120-pwrkey
+
+    required:
+      - compatible
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - '#interrupt-cells'
+  - interrupt-controller
+  - regulators
+  - powerkey
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      pmic@62 {
+        compatible = "richtek,rt5120";
+        reg = <0x62>;
+        interrupts-extended = <&gpio_intc 32 IRQ_TYPE_LEVEL_LOW>;
+        interrupt-controller;
+        #interrupt-cells = <1>;
+        wakeup-source;
+
+        regulators {
+          buck1 {
+            regulator-name = "rt5120-buck1";
+            regulator-min-microvolt = <600000>;
+            regulator-max-microvolt = <1393750>;
+            regulator-allowed-modes = <0 1>;
+            regulator-boot-on;
+          };
+          buck2 {
+            regulator-name = "rt5120-buck2";
+            regulator-min-microvolt = <1100000>;
+            regulator-max-microvolt = <1100000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+          };
+          buck3 {
+            regulator-name = "rt5120-buck3";
+            regulator-min-microvolt = <1800000>;
+            regulator-max-microvolt = <1800000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+          };
+          buck4 {
+            regulator-name = "rt5120-buck4";
+            regulator-min-microvolt = <3300000>;
+            regulator-max-microvolt = <3300000>;
+            regulator-allowed-modes = <0 1>;
+            regulator-always-on;
+          };
+          ldo {
+            regulator-name = "rt5120-ldo";
+            regulator-min-microvolt = <1800000>;
+            regulator-max-microvolt = <1800000>;
+            regulator-always-on;
+          };
+          exten {
+            regulator-name = "rt5120-exten";
+            regulator-min-microvolt = <3000000>;
+            regulator-max-microvolt = <3000000>;
+            regulator-always-on;
+          };
+        };
+        powerkey {
+          compatible = "richtek,rt5120-pwrkey";
+        };
+      };
+    };