regulator: Add MAX8893 bindings

Add Maxim MAX8893 PMIC device tree bindings. The example is also
provided.

Signed-off-by: Sergey Larin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: cerg2010cerg2010

Documentation/devicetree/bindings/regulator/max8893.yaml

@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/max8893.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Regulator driver for MAX8893 PMIC from Maxim Integrated.
+
+maintainers:
+  - Sergey Larin <[email protected]>
+
+description: |
+  The device has 5 LDO regulators and a single BUCK regulator.
+  Programming is done through I2C bus.
+
+properties:
+  compatible:
+    const: maxim,max8893
+
+  reg:
+    maxItems: 1
+
+  regulators:
+    type: object
+
+    patternProperties:
+      "^(ldo[1-5]|buck)$":
+        $ref: "regulator.yaml#"
+
+    additionalProperties: false
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - regulators
+
+examples:
+  - |
+    i2c {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            pmic@3e {
+                    compatible = "maxim,max8893";
+                    reg = <0x3e>;
+
+                    regulators {
+                            /* Front camera - s5k6aafx, back - m5mo */
+                            /* Numbers used to indicate the sequence */
+                            front_1_back_1: buck {
+                                    regulator-name = "cam_isp_core_1v2";
+                                    regulator-min-microvolt = <1200000>;
+                                    regulator-max-microvolt = <1200000>;
+                            };
+
+                            front_4_back_5: ldo1 {
+                                    regulator-name = "vt_io_1v8,cam_isp_1v8";
+                                    regulator-min-microvolt = <1800000>;
+                                    regulator-max-microvolt = <1800000>;
+                            };
+
+                            front_3_back_4: ldo2 {
+                                    regulator-name = "vt_core_1v5";
+                                    regulator-min-microvolt = <1500000>;
+                                    regulator-max-microvolt = <1500000>;
+                            };
+
+                            front_5_back_6: ldo3 {
+                                    regulator-name = "vt_cam_1v8,vt_sensor_io_1v8";
+                                    regulator-min-microvolt = <1800000>;
+                                    regulator-max-microvolt = <1800000>;
+                            };
+
+                            ldo4 {
+                                    /* not used */
+                            };
+
+                            back_7: ldo5 {
+                                    regulator-name = "cam_sensor_io_1v8";
+                                    regulator-min-microvolt = <1800000>;
+                                    regulator-max-microvolt = <1800000>;
+                            };
+                    };
+            };
+    };
+...