dt-bindings: power/supply: Add ltc4162-l-charger

Add support for the LTC4162-L Li-Ion battery charger. The driver allows
reading back telemetry and to set some charging options like the input
current limit.

This adds the devicetree bindings.
Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/devicetree/bindings/power/supply/ltc4162-l.yaml

+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright (C) 2020 Topic Embedded Products
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/power/supply/ltc4162-l.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Linear Technology (Analog Devices) LTC4162-L Charger
+
+maintainers:
+  - Mike Looijmans <mike.looijmans@topic.nl>
+
+description: |
+  The LTC ® 4162-L is an advanced monolithic synchronous step-down switching
+  battery charger and PowerPath (TM) manager that seamlessly manages power
+  distribution between input sources such as wall adapters, backplanes, solar
+  panels, etc., and a rechargeable Lithium-Ion/Polymer battery.
+
+  Specifications about the charger can be found at:
+    https://www.analog.com/en/products/ltc4162-s.html
+
+properties:
+  compatible:
+    enum:
+      - lltc,ltc4162-l
+
+  reg:
+    maxItems: 1
+    description: I2C address of the charger.
+
+  lltc,rsnsb-micro-ohms:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Battery sense resistor in microohm.
+    minimum: 1000
+
+  lltc,rsnsi-micro-ohms:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Input current sense resistor in microohm.
+    minimum: 1000
+
+  lltc,cell-count:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Number of battery cells. If not provided, will be obtained from the chip
+      once the external power is applied. Omit this when the number of cells
+      is somewhat dynamic. Without it, several measurements will return 0 until
+      the charger is connected to an external supply.
+
+required:
+  - compatible
+  - reg
+  - lltc,rsnsb-micro-ohms
+  - lltc,rsnsi-micro-ohms
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c0 {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      charger: battery-charger@68 {
+              compatible = "lltc,ltc4162-l";
+              reg = <0x68>;
+              lltc,rsnsb-micro-ohms = <10000>;
+              lltc,rsnsi-micro-ohms = <16000>;
+              lltc,cell-count = <2>;
+      };
+    };