[PATCH v2 1/9] dt-bindings: watchdog: renesas,wdt: Add support for RZ/T2H and RZ/N2H

Prabhakar
2025-07-29T15:59:23Z

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Extend the Renesas WDT device tree bindings to support the watchdog timer
found on the RZ/T2H (R9A09G077) and RZ/N2H (R9A09G087) SoCs.

The RZ/T2H WDT is mostly compatible with the one found on the RZ/V2H(P),
but includes an additional register and differs in the clock division
ratio settings for the WDTCR[CKS] field. To reflect these differences,
introduce a new compatible string, "renesas,r9a09g077-wdt".

The binding schema is updated accordingly. On RZ/T2H, the WDT does not
require the "resets" property. It also requires two register regions and
the presence of a "power-domains" property. The "clock-names" property is
limited to a single entry, "pclk", for this SoC.

The RZ/N2H SoC uses the same WDT IP as the RZ/T2H. It is supported by
using "renesas,r9a09g087-wdt" as the primary compatible string, with
"renesas,r9a09g077-wdt" listed as a fallback to describe the shared
hardware features.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
---
v1->v2:
- Dropped items from clock-names and instead added maxItems: 1.
- Added reviewed-by from Rob.
---
.../bindings/watchdog/renesas,wdt.yaml | 36 +++++++++++++++++--
1 file changed, 33 insertions(+), 3 deletions(-)

diff --git a/Documentation/devicetree/bindings/watchdog/renesas,wdt.yaml b/Documentation/devicetree/bindings/watchdog/renesas,wdt.yaml
index 78874b90c88c..b6e60162c263 100644
--- a/Documentation/devicetree/bindings/watchdog/renesas,wdt.yaml
+++ b/Documentation/devicetree/bindings/watchdog/renesas,wdt.yaml
@@ -81,10 +81,17 @@ properties:
- renesas,r9a09g056-wdt # RZ/V2N
- const: renesas,r9a09g057-wdt # RZ/V2H(P)

- - const: renesas,r9a09g057-wdt # RZ/V2H(P)
+ - enum:
+ - renesas,r9a09g057-wdt # RZ/V2H(P)
+ - renesas,r9a09g077-wdt # RZ/T2H
+
+ - items:
+ - const: renesas,r9a09g087-wdt # RZ/N2H
+ - const: renesas,r9a09g077-wdt # RZ/T2H

reg:
- maxItems: 1
+ minItems: 1
+ maxItems: 2

interrupts:
minItems: 1
@@ -132,6 +139,7 @@ allOf:
compatible:
contains:
enum:
+ - renesas,r9a09g077-wdt
- renesas,rza-wdt
- renesas,rzn1-wdt
then:
@@ -183,7 +191,9 @@ allOf:
properties:
compatible:
contains:
- const: renesas,r9a09g057-wdt
+ enum:
+ - renesas,r9a09g057-wdt
+ - renesas,r9a09g077-wdt
then:
properties:
interrupts: false
@@ -192,6 +202,26 @@ allOf:
required:
- interrupts

+ - if:
+ properties:
+ compatible:
+ contains:
+ const: renesas,r9a09g077-wdt
+ then:
+ properties:
+ resets: false
+ clock-names:
+ maxItems: 1
+ reg:
+ minItems: 2
+ required:
+ - clock-names
+ - power-domains
+ else:
+ properties:
+ reg:
+ maxItems: 1
+
additionalProperties: false

examples:
--
2.50.1