dt-bindings: mfd: Add MAX5970 and MAX5978

The MAX597x is a hot swap controller with configurable fault protection.
It also has 10bit ADC for current & voltage measurements.

...
Changes in V12:
- Update title
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Co-developed-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Co-developed-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Link: https://lore.kernel.org/r/20230307121246.127425-1-Naresh.Solanki@9elements.com

Documentation/devicetree/bindings/mfd/maxim,max5970.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/maxim,max5970.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Regulator for MAX5970 Smart Switch from Maxim Integrated
+
+maintainers:
+  - Patrick Rudolph <patrick.rudolph@9elements.com>
+
+description: |
+  The smart switch provides no output regulation, but independent fault protection
+  and voltage and current sensing.
+  Programming is done through I2C bus.
+
+  Datasheets:
+    https://datasheets.maximintegrated.com/en/ds/MAX5970.pdf
+    https://datasheets.maximintegrated.com/en/ds/MAX5978.pdf
+
+properties:
+  compatible:
+    enum:
+      - maxim,max5970
+      - maxim,max5978
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  leds:
+    type: object
+    description:
+      Properties for four LEDS.
+
+    properties:
+      "#address-cells":
+        const: 1
+
+      "#size-cells":
+        const: 0
+
+    patternProperties:
+      "^led@[0-3]$":
+        $ref: /schemas/leds/common.yaml#
+        type: object
+
+    additionalProperties: false
+
+  vss1-supply:
+    description: Supply of the first channel.
+
+  vss2-supply:
+    description: Supply of the second channel.
+
+  regulators:
+    type: object
+    description:
+      Properties for both hot swap control/switch.
+
+    patternProperties:
+      "^sw[0-1]$":
+        $ref: /schemas/regulator/regulator.yaml#
+        type: object
+        properties:
+          shunt-resistor-micro-ohms:
+            description: |
+              The value of current sense resistor in microohms.
+
+        required:
+          - shunt-resistor-micro-ohms
+
+        unevaluatedProperties: false
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - regulators
+  - vss1-supply
+
+allOf:
+  - if:
+      properties:
+        compatible:
+          enum:
+            - maxim,max5970
+    then:
+      required:
+        - vss2-supply
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        regulator@3a {
+            compatible = "maxim,max5978";
+            reg = <0x3a>;
+            vss1-supply = <&p3v3>;
+
+            regulators {
+                sw0_ref_0: sw0 {
+                    shunt-resistor-micro-ohms = <12000>;
+                };
+            };
+
+            leds {
+                #address-cells = <1>;
+                #size-cells = <0>;
+                led@0 {
+                    reg = <0>;
+                    label = "led0";
+                    default-state = "on";
+                };
+                led@1 {
+                    reg = <1>;
+                    label = "led1";
+                    default-state = "on";
+                };
+            };
+        };
+    };
+
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        regulator@3a {
+            compatible = "maxim,max5970";
+            reg = <0x3a>;
+            vss1-supply = <&p3v3>;
+            vss2-supply = <&p5v>;
+
+            regulators {
+                sw0_ref_1: sw0 {
+                    shunt-resistor-micro-ohms = <12000>;
+                };
+                sw1_ref_1: sw1 {
+                    shunt-resistor-micro-ohms = <10000>;
+                };
+            };
+        };
+    };
+...