dts: nrf: Add bindings for CLOCK, POWER, RTC, and TIMER peripherals

Add dts bindings for nRF CLOCK, POWER, RTC, and TIMER peripherals.

Signed-off-by: Andrzej Głąbek <andrzej.glabek@nordicsemi.no>

dts/bindings/clock/nrf-clock.yaml

@@ -0,0 +1,31 @@
+#
+# Copyright (c) 2018 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+---
+title: Nordic nRF clock control
+version: 0.1
+
+description: >
+    This is a representation of the Nordic nRF clock control node
+
+properties:
+    compatible:
+      type: string
+      category: required
+      description: compatible strings
+      constraint: "nordic,nrf-clock"
+
+    reg:
+      type: array
+      category: required
+      description: mmio register space
+      generation: define
+
+    interrupts:
+      type: array
+      category: required
+      description: required interrupts
+      generation: define
+...

dts/bindings/power/nrf-power.yaml

@@ -0,0 +1,31 @@
+#
+# Copyright (c) 2018 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+---
+title: Nordic nRF power control
+version: 0.1
+
+description: >
+    This is a representation of the Nordic nRF power control node
+
+properties:
+    compatible:
+      type: string
+      category: required
+      description: compatible strings
+      constraint: "nordic,nrf-power"
+
+    reg:
+      type: array
+      category: required
+      description: mmio register space
+      generation: define
+
+    interrupts:
+      type: array
+      category: required
+      description: required interrupts
+      generation: define
+...

dts/bindings/rtc/nordic,nrf-rtc.yaml

@@ -0,0 +1,25 @@
+#
+# Copyright (c) 2018 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+---
+title: Nordic nRF Real Time Counter
+version: 0.1
+
+description: >
+    This is a representation of the Nordic nRF RTC node
+
+inherits:
+    !include rtc.yaml
+
+properties:
+    compatible:
+      constraint: "nordic,nrf-rtc"
+
+    reg:
+      type: array
+      description: mmio register space
+      generation: define
+      category: required
+...

dts/bindings/timer/nordic,nrf-timer.yaml

@@ -0,0 +1,37 @@
+#
+# Copyright (c) 2018 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+---
+title: Nordic nRF timer
+version: 0.1
+
+description: >
+    This is a representation of the Nordic nRF timer node
+
+properties:
+    compatible:
+      type: string
+      category: required
+      description: compatible strings
+      constraint: "nordic,nrf-timer"
+
+    reg:
+      type: array
+      category: required
+      description: mmio register space
+      generation: define
+
+    interrupts:
+      type: array
+      category: required
+      description: required interrupts
+      generation: define
+
+    label:
+      type: string
+      category: required
+      description: Human readable string describing the device (used by Zephyr for API name)
+      generation: define
+...