dt-bindings: power: supply: Document Maxim MAX8971 charger

Add bindings for Maxim MAX8971 charger.

Signed-off-by: Svyatoslav Ryhel <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Sebastian Reichel <[e-mail]>

Documentation/devicetree/bindings/power/supply/maxim,max8971.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/power/supply/maxim,max8971.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Maxim MAX8971 IC charger
+
+maintainers:
+  - Svyatoslav Ryhel <[e-mail]>
+
+description:
+  The MAX8971 is a compact, high-frequency, high-efficiency switch-mode charger
+  for a one-cell lithium-ion (Li+) battery.
+
+allOf:
+  - $ref: power-supply.yaml#
+
+properties:
+  compatible:
+    const: maxim,max8971
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  monitored-battery: true
+
+  port:
+    description:
+      An optional port node to link the extcon device to detect type of plug.
+    $ref: /schemas/graph.yaml#/properties/port
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        charger@35 {
+            compatible = "maxim,max8971";
+            reg = <0x35>;
+
+            interrupt-parent = <&gpio>;
+            interrupts = <74 IRQ_TYPE_LEVEL_LOW>;
+
+            monitored-battery = <&battery>;
+
+            port {
+                charger_input: endpoint {
+                    remote-endpoint = <&extcon_output>;
+                };
+            };
+        };
+    };
+...