[PATCH 2/7] dt-bindings: watchdog: dw-wdt: Add watchdog TOPs array property

[<Sergey.Semin@baikalelectronics.ru>]

From: Serge Semin <Sergey.Semin@baikalelectronics.ru>

In case if DW Watchdog IP core is built with WDT_USE_FIX_TOP == false,
a custom timeout periods are used to preset the timer counter. In
this case that periods should be specified in a new "snps,watchdog-tops"
property of the DW watchdog dts node.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Signed-off-by: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
---
 .../bindings/watchdog/snps,dw-wdt.yaml        | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml b/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml
index 8b30f9601c38..1b3b71351628 100644
--- a/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml
+++ b/Documentation/devicetree/bindings/watchdog/snps,dw-wdt.yaml
@@ -46,6 +46,21 @@ properties:
     description: Phandle to the DW Watchdog reset lane.
     maxItems: 1
 
+  snps,watchdog-tops:
+    description: |
+      DW APB Watchdog custom timer intervals - Timeout Period ranges (TOPs).
+      Each TOP is a number loaded into the watchdog counter at the moment of
+      the timer restart. The counter decrementing happens each tick of the
+      reference clock. Therefore the TOPs array is equivalent to an array of
+      the timer expiration intervals supported by the DW APB Watchdog. Note
+      DW APB Watchdog IP-cores might be synthesized with fixed TOP values,
+      in which case this property is unnecessary.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32-array
+      - items:
+          minItems: 16
+          maxItems: 16
+
 additionalProperties: false
 
 required:
@@ -63,4 +78,19 @@ examples:
       clocks = <&per_base_clk>;
       resets = <&wdt_rst>;
     };
+
+  - |
+    watchdog1: watchdog@ffd02000 {
+      compatible = "snps,dw-wdt";
+      reg = <0xffd02000 0x1000>;
+      interrupts = <0 171 4>;
+      clocks = <&per_base_clk>;
+      clock-names = "tclk";
+      snps,watchdog-tops = <0x000000FF 0x000001FF 0x000003FF
+                            0x000007FF 0x0000FFFF 0x0001FFFF
+                            0x0003FFFF 0x0007FFFF 0x000FFFFF
+                            0x001FFFFF 0x003FFFFF 0x007FFFFF
+                            0x00FFFFFF 0x01FFFFFF 0x03FFFFFF
+                            0x07FFFFFF>;
+    };
 ...
-- 
2.25.1