linux-kernel - Re: [PATCH] dt-bindings: power: reset: restart-handler: add common schema

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Message-ID: <20220907163218.aja4pazw3sbxnoop@pali>
Date:   Wed, 7 Sep 2022 18:32:18 +0200
From:   Pali Rohár <pali@...nel.org>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        linux-pm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] dt-bindings: power: reset: restart-handler: add common
 schema

On Wednesday 07 September 2022 14:36:30 Krzysztof Kozlowski wrote:
> Add common schema for restart and shutdown handlers, so they all use
> same meaning of "priority" field.  The Linux drivers already have this
> property and some systems want to customize it per-board in DTS.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> 
> ---
> 
> See also:
> https://lore.kernel.org/all/8fe93da3-f768-16ae-7025-1cfa97a42b27@linaro.org/
> https://lore.kernel.org/all/20220831081715.14673-1-pali@kernel.org/
> ---
>  .../bindings/power/reset/gpio-restart.yaml    | 13 ++------
>  .../bindings/power/reset/restart-handler.yaml | 30 +++++++++++++++++++
>  2 files changed, 33 insertions(+), 10 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/power/reset/restart-handler.yaml
> 
> diff --git a/Documentation/devicetree/bindings/power/reset/gpio-restart.yaml b/Documentation/devicetree/bindings/power/reset/gpio-restart.yaml
> index a72d5c721516..d3d18e0f5db3 100644
> --- a/Documentation/devicetree/bindings/power/reset/gpio-restart.yaml
> +++ b/Documentation/devicetree/bindings/power/reset/gpio-restart.yaml
> @@ -25,6 +25,9 @@ description: >
>    inactive-delay, the GPIO is driven active again.  After a delay specified by wait-delay, the
>    restart handler completes allowing other restart handlers to be attempted.
>  
> +allOf:
> +  - $ref: restart-handler.yaml#
> +
>  properties:
>    compatible:
>      const: gpio-restart
> @@ -41,16 +44,6 @@ properties:
>        in its inactive state.
>  
>    priority:
> -    $ref: /schemas/types.yaml#/definitions/uint32
> -    description: |
> -      A priority ranging from 0 to 255 (default 129) according to the following guidelines:
> -
> -        0:   Restart handler of last resort, with limited restart capabilities.
> -        128: Default restart handler; use if no other restart handler is expected to be available,
> -             and/or if restart functionality is sufficient to restart the entire system.
> -        255: Highest priority restart handler, will preempt all other restart handlers.
> -    minimum: 0
> -    maximum: 255
>      default: 129
>  
>    active-delay:
> diff --git a/Documentation/devicetree/bindings/power/reset/restart-handler.yaml b/Documentation/devicetree/bindings/power/reset/restart-handler.yaml
> new file mode 100644
> index 000000000000..f5d22ca0cd45
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/reset/restart-handler.yaml
> @@ -0,0 +1,30 @@
> +# SPDX-License-Identifier: GPL-2.0-only or BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/power/reset/restart-handler.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Restart and shutdown handler generic binding
> +
> +maintainers:
> +  - Sebastian Reichel <sre@...nel.org>
> +
> +description:
> +  Restart and shutdown handler device is responsible for powering off the
> +  system, e.g. my cutting off the power.  System might have several restart
> +  handlers, which usually are tried from most precise to last resort.
> +
> +properties:
> +  priority:
> +    $ref: /schemas/types.yaml#/definitions/uint32

IIRC priority is signed integer number, not unsigned.

> +    description: |
> +      A priority ranging from 0 to 255 according to the following guidelines::
> +        0:   Restart handler of last resort, with limited restart capabilities.
> +        128: Typical, default restart handler; use if no other restart handler
> +             is expected to be available, and/or if restart functionality is
> +             sufficient to restart the entire system.
> +        255: Highest priority restart handler, will preempt all other restart handlers.
> +    minimum: 0
> +    maximum: 255

And IIRC also other values (above 255 or below 0) are allowed for tuning
two "highest" or two "last resort" handlers.

This needs to be checked / tested to ensure that new schema is not incorrect.

> +
> +additionalProperties: true
> -- 
> 2.34.1
>