[v3,1/2] dt-bindings: watchdog: Realtek Otto WDT binding

Add a binding description for Realtek's watchdog timer as found on
several of their MIPS-based SoCs (codenamed Otto), such as the RTL838x,
RTL839x, and RTL930x series of switch SoCs.

Signed-off-by: Sander Vanheule <sander@svanheule.net>
Reviewed-by: Rob Herring <robh@kernel.org>

--
v2:
- add realtek,rtl9300-wdt compatible
- make interrupts property required
- add Rob's Reviewed-by tag
---
 .../bindings/watchdog/realtek,otto-wdt.yaml   | 91 +++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/realtek,otto-wdt.yaml

On Thu, Nov 04, 2021 at 10:32:12AM +0100, Sander Vanheule wrote:
> Add a binding description for Realtek's watchdog timer as found on
> several of their MIPS-based SoCs (codenamed Otto), such as the RTL838x,
> RTL839x, and RTL930x series of switch SoCs.
> 
> Signed-off-by: Sander Vanheule <sander@svanheule.net>
> Reviewed-by: Rob Herring <robh@kernel.org>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> 
> --

For the future, change log after '---', please.

> v2:
> - add realtek,rtl9300-wdt compatible
> - make interrupts property required
> - add Rob's Reviewed-by tag
> ---
>  .../bindings/watchdog/realtek,otto-wdt.yaml   | 91 +++++++++++++++++++
>  1 file changed, 91 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/realtek,otto-wdt.yaml
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/realtek,otto-wdt.yaml b/Documentation/devicetree/bindings/watchdog/realtek,otto-wdt.yaml
> new file mode 100644
> index 000000000000..11b220a5e0f6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/realtek,otto-wdt.yaml
> @@ -0,0 +1,91 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/watchdog/realtek,otto-wdt.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Realtek Otto watchdog timer
> +
> +maintainers:
> +  - Sander Vanheule <sander@svanheule.net>
> +
> +description: |
> +  The timer has two timeout phases. Both phases have a maximum duration of 32
> +  prescaled clock ticks, which is ca. 43s with a bus clock of 200MHz. The
> +  minimum duration of each phase is one tick. Each phase can trigger an
> +  interrupt, although the phase 2 interrupt will occur with the system reset.
> +  - Phase 1: During this phase, the WDT can be pinged to reset the timeout.
> +  - Phase 2: Starts after phase 1 has timed out, and only serves to give the
> +    system some time to clean up, or notify others that it's going to reset.
> +    During this phase, pinging the WDT has no effect, and a reset is
> +    unavoidable, unless the WDT is disabled.
> +
> +allOf:
> +  - $ref: watchdog.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - realtek,rtl8380-wdt
> +      - realtek,rtl8390-wdt
> +      - realtek,rtl9300-wdt
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  interrupts:
> +    items:
> +      - description: interrupt specifier for pretimeout
> +      - description: interrupt specifier for timeout
> +
> +  interrupt-names:
> +    items:
> +      - const: phase1
> +      - const: phase2
> +
> +  realtek,reset-mode:
> +    $ref: /schemas/types.yaml#/definitions/string
> +    description: |
> +      Specify how the system is reset after a timeout. Defaults to "cpu" if
> +      left unspecified.
> +    oneOf:
> +      - description: Reset the entire chip
> +        const: soc
> +      - description: |
> +          Reset the CPU and IPsec engine, but leave other peripherals untouched
> +        const: cpu
> +      - description: |
> +          Reset the execution pointer, but don't actually reset any hardware
> +        const: software
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - interrupts
> +
> +unevaluatedProperties: false
> +
> +dependencies:
> +  interrupts: [ interrupt-names ]
> +
> +examples:
> +  - |
> +    watchdog: watchdog@3150 {
> +        compatible = "realtek,rtl8380-wdt";
> +        reg = <0x3150 0xc>;
> +
> +        realtek,reset-mode = "soc";
> +
> +        clocks = <&lxbus_clock>;
> +        timeout-sec = <20>;
> +
> +        interrupt-parent = <&rtlintc>;
> +        interrupt-names = "phase1", "phase2";
> +        interrupts = <19>, <18>;
> +    };
> +
> +...
> -- 
> 2.31.1
>