dt-bindings: Add devicetree bindings

Add snapshot of device tree bindings from keystone common kernel, branch
"android-mainline-keystone-qcom-release" at c4c12103f9c0 ("Snap for 9228065
from e32903b9a63bb558df8b803b076619c53c16baad to
android-mainline-keystone-qcom-release").

Change-Id: I7682079615cbd9f29340a5c1f2a1d84ec441a1f1
Signed-off-by: Melody Olvera <quic_molvera@quicinc.com>

bindings/regulator/pwm-regulator.yaml

@@ -0,0 +1,126 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/regulator/pwm-regulator.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Bindings for the Generic PWM Regulator
+
+maintainers:
+  - Brian Norris <briannorris@chromium.org>
+  - Lee Jones <lee@kernel.org>
+  - Alexandre Courbot <acourbot@nvidia.com>
+
+description: |
+  Currently supports 2 modes of operation:
+
+  Voltage Table:
+    When in this mode, a voltage table (See below) of predefined voltage <=>
+    duty-cycle values must be provided via DT. Limitations are that the
+    regulator can only operate at the voltages supplied in the table.
+    Intermediary duty-cycle values which would normally allow finer grained
+    voltage selection are ignored and rendered useless.  Although more control
+    is given to the user if the assumptions made in continuous-voltage mode do
+    not reign true.
+
+  Continuous Voltage:
+    This mode uses the regulator's maximum and minimum supplied voltages
+    specified in the regulator-{min,max}-microvolt properties to calculate
+    appropriate duty-cycle values.  This allows for a much more fine grained
+    solution when compared with voltage-table mode above.  This solution does
+    make an assumption that a %50 duty-cycle value will cause the regulator
+    voltage to run at half way between the supplied max_uV and min_uV values.
+
+  If voltage-table is provided, then the device will be used in Voltage Table
+  Mode.  If no voltage-table is provided, then the device will be used in
+  Continuous Voltage Mode.
+
+allOf:
+  - $ref: regulator.yaml#
+
+properties:
+  compatible:
+    const: pwm-regulator
+
+  pwms:
+    maxItems: 1
+
+  voltage-table:
+    description: Voltage and Duty-Cycle table.
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+    items:
+      items:
+        - description: voltage in microvolts (uV)
+        - description: duty-cycle in percent (%)
+
+  enable-gpios:
+    description: Regulator enable GPIO
+    maxItems: 1
+
+   # Optional properties for Continuous mode:
+  pwm-dutycycle-unit:
+    description:
+      Integer value encoding the duty cycle unit. If not
+        defined, <100> is assumed, meaning that
+        pwm-dutycycle-range contains values expressed in
+        percent.
+    default: 100
+
+  pwm-dutycycle-range:
+    description:
+      Should contain 2 entries. The first entry is encoding
+        the dutycycle for regulator-min-microvolt and the
+        second one the dutycycle for regulator-max-microvolt.
+        Duty cycle values are expressed in pwm-dutycycle-unit.
+        If not defined, <0 100> is assumed.
+    $ref: /schemas/types.yaml#/definitions/uint32-array
+    items:
+      - description: the dutycycle for regulator-min-microvolt
+      - description: the dutycycle for regulator-max-microvolt
+    default: [ 0 100 ]
+
+required:
+  - compatible
+  - pwms
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    // Continuous Voltage With Enable GPIO Example:
+    regulator {
+        compatible = "pwm-regulator";
+        pwms = <&pwm1 0 8448 0>;
+        enable-gpios = <&gpio0 23 GPIO_ACTIVE_HIGH>;
+        regulator-min-microvolt = <1016000>;
+        regulator-max-microvolt = <1114000>;
+        regulator-name = "vdd_logic";
+        /* unit == per-mille */
+        pwm-dutycycle-unit = <1000>;
+        /*
+        * Inverted PWM logic, and the duty cycle range is limited
+        * to 30%-70%.
+        */
+        pwm-dutycycle-range = <700 300>; /* */
+    };
+
+  - |
+    // Voltage Table Example:
+    regulator {
+        compatible = "pwm-regulator";
+        pwms = <&pwm1 0 8448 0>;
+        regulator-min-microvolt = <1016000>;
+        regulator-max-microvolt = <1114000>;
+        regulator-name = "vdd_logic";
+
+                /* Voltage Duty-Cycle */
+        voltage-table = <1114000 0>,
+            <1095000 10>,
+            <1076000 20>,
+            <1056000 30>,
+            <1036000 40>,
+            <1016000 50>;
+    };
+...