[PATCH 1/2] dt-bindings: timer: Add ARM SSE(Subsystems for Embedded) timer

[Jisheng Zhang <jszhang@kernel.org>]

Add binding doc for the ARM SSE(Subsystems for Embedded) timer. Here
is the document URL:
https://developer.arm.com/documentation/107610/0000/System-timer-components?lang=en

Although the IP is mostly seen on MCU SoC platforms, but nothing
prevent it from being integrated into linux capable SoC platforms.

The IP core may have a system counter to generate timestamp value,
a system timer to raise an interrupt when a period has elapsed, and
a System Watchdog to detect errant system behaviour then reset the
system if a period elapses without ping.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 .../bindings/timer/arm,sse_timer.yaml         | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/timer/arm,sse_timer.yaml

diff --git a/Documentation/devicetree/bindings/timer/arm,sse_timer.yaml b/Documentation/devicetree/bindings/timer/arm,sse_timer.yaml
new file mode 100644
index 000000000000..37a79f9052d0
--- /dev/null
+++ b/Documentation/devicetree/bindings/timer/arm,sse_timer.yaml
@@ -0,0 +1,90 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/timer/arm,sse_timer.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ARM SSE(Subsystems for Embedded) system timer
+
+maintainers:
+  - Jisheng Zhang <jszhang@kernel.org>
+
+description: |+
+  ARM SSE(Subsystems for Embedded) system timer core may have a system counter
+  to generate timestamp value, a system timer to raise an interrupt when a
+  period has elapsed, and a System Watchdog to detect errant system behaviour
+  then reset the system if a period elapses without ping.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - arm,sse-timer
+
+  reg:
+    maxItems: 1
+    description: The system counter control frame base
+
+  clocks:
+    maxItems: 1
+
+  '#address-cells':
+    enum: [1, 2]
+
+  '#size-cells':
+    const: 1
+
+  ranges: true
+
+patternProperties:
+  '^frame@[0-9a-f]+$':
+    type: object
+    additionalProperties: false
+    description: A timer node has some frame sub-nodes, each frame can be timer frame or watchdog frame. Each frame has the following properties.
+    properties:
+      interrupts:
+        minItems: 1
+        items:
+          - description: timer irq
+
+      reg:
+        minItems: 1
+        items:
+          - description: 1st view base address
+          - description: 2nd optional view base address if this is a watchdog frame
+
+    required:
+      - interrupts
+      - reg
+
+required:
+  - compatible
+  - reg
+  - '#address-cells'
+  - '#size-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    timer@f7f3e000 {
+      compatible = "arm,sse-timer";
+      #address-cells = <1>;
+      #size-cells = <1>;
+      ranges;
+      reg = <0xf7f3e000 0x2000>;
+      clocks = <&core_clk>;
+
+      frame@f7f20000 {
+        reg = <0xf7f20000 0x1000>;
+        interrupts = <0 26 0x8>;
+      };
+
+      frame@f7f30000 {
+        interrupts = <0 15 0x8>;
+        reg = <0xf7f32000 0x1000>,
+              <0xf7f33000 0x1000>;
+      };
+    };
+
+...
-- 
2.50.1