dt-bindings: mfd: maxim,max77843: Add MAX77843 bindings

Document the bindings for MAX77843 MFD driver, based on Exynos5433 TM2
devicetree.  These are neither accurate nor finished bindings but at
least allow parsing existing DTS files.

The example DTS was copied from existing DTS
(exynos5433-tm2-common.dtsi), so keep the license as GPL-2.0-only.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20220111174805.223732-5-krzysztof.kozlowski@canonical.com

Documentation/devicetree/bindings/mfd/maxim,max77843.yaml

+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/maxim,max77843.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim MAX77843 MicroUSB and Companion Power Management IC
+
+maintainers:
+  - Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
+
+description: |
+  This is a part of device tree bindings for Maxim MAX77843 MicroUSB
+  Integrated Circuit (MUIC).
+
+  The Maxim MAX77843 is a MicroUSB and Companion Power Management IC which
+  includes voltage current regulators, charger, fuel-gauge, haptic motor driver
+  and MicroUSB management IC.
+
+properties:
+  compatible:
+    const: maxim,max77843
+
+  interrupts:
+    maxItems: 1
+
+  reg:
+    maxItems: 1
+
+  extcon:
+    $ref: /schemas/extcon/maxim,max77843.yaml
+
+  motor-driver:
+    type: object
+    properties:
+      compatible:
+        const: maxim,max77843-haptic
+
+      haptic-supply:
+        description: Power supply to the haptic motor
+
+      pwms:
+        maxItems: 1
+
+    required:
+      - compatible
+      - haptic-supply
+      - pwms
+
+  regulators:
+    $ref: /schemas/regulator/maxim,max77843.yaml
+
+required:
+  - compatible
+  - interrupts
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        pmic@66 {
+            compatible = "maxim,max77843";
+            interrupt-parent = <&gpa1>;
+            interrupts = <5 IRQ_TYPE_EDGE_FALLING>;
+            reg = <0x66>;
+
+            extcon {
+                compatible = "maxim,max77843-muic";
+
+                connector {
+                    compatible = "samsung,usb-connector-11pin",
+                                 "usb-b-connector";
+                    label = "micro-USB";
+                    type = "micro";
+
+                    ports {
+                        #address-cells = <1>;
+                        #size-cells = <0>;
+
+                        port@0 {
+                            /*
+                             * TODO: The DTS this is based on does not have
+                             * port@0 which is a required property. The ports
+                             * look incomplete and need fixing.
+                             * Add a disabled port just to satisfy dtschema.
+                             */
+                            reg = <0>;
+                            status = "disabled";
+                        };
+
+                        port@3 {
+                            reg = <3>;
+                            endpoint {
+                                remote-endpoint = <&mhl_to_musb_con>;
+                            };
+                        };
+                    };
+                };
+
+                ports {
+                    port {
+                        endpoint {
+                            remote-endpoint = <&usb_to_muic>;
+                        };
+                    };
+                };
+            };
+
+            regulators {
+                compatible = "maxim,max77843-regulator";
+
+                SAFEOUT1 {
+                    regulator-name = "SAFEOUT1";
+                    regulator-min-microvolt = <3300000>;
+                    regulator-max-microvolt = <4950000>;
+                };
+
+                SAFEOUT2 {
+                    regulator-name = "SAFEOUT2";
+                    regulator-min-microvolt = <3300000>;
+                    regulator-max-microvolt = <4950000>;
+                };
+
+                CHARGER {
+                    regulator-name = "CHARGER";
+                    regulator-min-microamp = <100000>;
+                    regulator-max-microamp = <3150000>;
+                };
+            };
+
+            motor-driver {
+                compatible = "maxim,max77843-haptic";
+                haptic-supply = <&ldo38_reg>;
+                pwms = <&pwm 0 33670 0>;
+            };
+        };
+    };