dt-bindings: mfd: Add binding for the PF1550 PMIC

Add a DT binding document for pf1550 PMIC. This describes the core MFD
device along with its children: regulators, charger and onkey.

Signed-off-by: Samuel Kayode <samuel.kayode@savoirfairelinux.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Tested-by: Sean Nyekjaer <sean@geanix.com>
Link: https://patch.msgid.link/20251001-pf1550-v12-1-a3302aa41687@savoirfairelinux.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: skayodesfl

Documentation/devicetree/bindings/mfd/nxp,pf1550.yaml

@@ -0,0 +1,161 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/nxp,pf1550.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP PF1550 Power Management IC
+
+maintainers:
+  - Samuel Kayode <samuel.kayode@savoirfairelinux.com>
+
+description:
+  PF1550 PMIC provides battery charging and power supply for low power IoT and
+  wearable applications. This device consists of an i2c controlled MFD that
+  includes regulators, battery charging and an onkey/power button.
+
+$ref: /schemas/power/supply/power-supply.yaml
+
+properties:
+  compatible:
+    const: nxp,pf1550
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  wakeup-source: true
+
+  regulators:
+    type: object
+    additionalProperties: false
+
+    patternProperties:
+      "^(ldo[1-3]|sw[1-3]|vrefddr)$":
+        type: object
+        $ref: /schemas/regulator/regulator.yaml
+        description:
+          regulator configuration for ldo1-3, buck converters(sw1-3)
+          and DDR termination reference voltage (vrefddr)
+        unevaluatedProperties: false
+
+  monitored-battery:
+    description: |
+      A phandle to a monitored battery node that contains a valid value
+      for:
+      constant-charge-voltage-max-microvolt.
+
+  nxp,thermal-regulation-celsius:
+    description:
+      Temperature threshold for thermal regulation of charger in celsius.
+    enum: [ 80, 95, 110, 125 ]
+
+  nxp,min-system-microvolt:
+    description:
+      System specific lower limit voltage.
+    enum: [ 3500000, 3700000, 4300000 ]
+
+  nxp,disable-key-power:
+    type: boolean
+    description:
+      Disable power-down using a long key-press. The onkey driver will remove
+      support for the KEY_POWER key press when triggered using a long press of
+      the onkey.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/input/linux-event-codes.h>
+
+    battery: battery-cell {
+        compatible = "simple-battery";
+        constant-charge-voltage-max-microvolt = <4400000>;
+    };
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        pmic@8 {
+            compatible = "nxp,pf1550";
+            reg = <0x8>;
+
+            interrupt-parent = <&gpio1>;
+            interrupts = <2 IRQ_TYPE_LEVEL_LOW>;
+            wakeup-source;
+            monitored-battery = <&battery>;
+            nxp,min-system-microvolt = <4300000>;
+            nxp,thermal-regulation-celsius = <80>;
+
+            regulators {
+                sw1_reg: sw1 {
+                    regulator-name = "sw1";
+                    regulator-min-microvolt = <600000>;
+                    regulator-max-microvolt = <1387500>;
+                    regulator-always-on;
+                    regulator-ramp-delay = <6250>;
+
+                    regulator-state-mem {
+                        regulator-on-in-suspend;
+                        regulator-suspend-min-microvolt = <1270000>;
+                    };
+                };
+
+                sw2_reg: sw2 {
+                    regulator-name = "sw2";
+                    regulator-min-microvolt = <600000>;
+                    regulator-max-microvolt = <1387500>;
+                    regulator-always-on;
+
+                    regulator-state-mem {
+                        regulator-on-in-suspend;
+                    };
+                };
+
+                sw3_reg: sw3 {
+                    regulator-name = "sw3";
+                    regulator-min-microvolt = <1800000>;
+                    regulator-max-microvolt = <3300000>;
+                    regulator-always-on;
+
+                    regulator-state-mem {
+                        regulator-on-in-suspend;
+                    };
+                };
+
+                vldo1_reg: ldo1 {
+                    regulator-name = "ldo1";
+                    regulator-min-microvolt = <750000>;
+                    regulator-max-microvolt = <3300000>;
+                    regulator-always-on;
+
+                    regulator-state-mem {
+                        regulator-off-in-suspend;
+                    };
+                };
+
+                vldo2_reg: ldo2 {
+                    regulator-name = "ldo2";
+                    regulator-min-microvolt = <1800000>;
+                    regulator-max-microvolt = <3300000>;
+                    regulator-always-on;
+                };
+
+                vldo3_reg: ldo3 {
+                    regulator-name = "ldo3";
+                    regulator-min-microvolt = <750000>;
+                    regulator-max-microvolt = <3300000>;
+                    regulator-always-on;
+                };
+            };
+        };
+    };