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/pwm/pwm-sifive.yaml

@@ -0,0 +1,73 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 SiFive, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/pwm-sifive.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SiFive PWM controller
+
+maintainers:
+  - Sagar Kadam <sagar.kadam@sifive.com>
+  - Paul Walmsley <paul.walmsley@sifive.com>
+
+description:
+  Unlike most other PWM controllers, the SiFive PWM controller currently
+  only supports one period for all channels in the PWM. All PWMs need to
+  run at the same period. The period also has significant restrictions on
+  the values it can achieve, which the driver rounds to the nearest
+  achievable period. PWM RTL that corresponds to the IP block version
+  numbers can be found here -
+
+  https://github.com/sifive/sifive-blocks/tree/master/src/main/scala/devices/pwm
+
+allOf:
+  - $ref: pwm.yaml#
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - sifive,fu540-c000-pwm
+          - sifive,fu740-c000-pwm
+      - const: sifive,pwm0
+    description:
+      Should be "sifive,<chip>-pwm" and "sifive,pwm<version>". Supported
+      compatible strings are "sifive,fu540-c000-pwm" and
+      "sifive,fu740-c000-pwm" for the SiFive PWM v0 as integrated onto the
+      SiFive FU540 and FU740 chip respectively, and "sifive,pwm0" for the
+      SiFive PWM v0 IP block with no chip integration tweaks.
+      Please refer to sifive-blocks-ip-versioning.txt for details.
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  "#pwm-cells":
+    const: 3
+
+  interrupts:
+    maxItems: 4
+    description:
+      Each PWM instance in FU540-C000 has 4 comparators. One interrupt per comparator.
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - interrupts
+
+additionalProperties: false
+
+examples:
+  - |
+    pwm:  pwm@10020000 {
+      compatible = "sifive,fu540-c000-pwm", "sifive,pwm0";
+      reg = <0x10020000 0x1000>;
+      clocks = <&tlclk>;
+      interrupt-parent = <&plic>;
+      interrupts = <42>, <43>, <44>, <45>;
+      #pwm-cells = <3>;
+    };