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Date:   Fri, 4 Feb 2022 10:46:14 +0100
From:   Alexandre Belloni <alexandre.belloni@bootlin.com>
To:     Eugen Hristev <eugen.hristev@microchip.com>
Cc:     robh+dt@kernel.org, nicolas.ferre@microchip.com,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, clement.leger@bootlin.com
Subject: Re: [PATCH] dt-bindings: microchip: atmel,at91rm9200-tcb: remove
 mandatory interrupts property
Message-ID: <Yfz15ta50G5WC158@piout.net>
References: <20220204081446.474991-1-eugen.hristev@microchip.com>
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On 04/02/2022 10:14:46+0200, Eugen Hristev wrote:
> The timer block can be used only to be read and to measure time in a polling
> fashion. This can be used by Linux like this for example, or it can be used
> by different projects which do not have interrupt controllers, or do not
> wish to enable them (e.g. U-boot).
> As DT is ABI, the binding should relate to all possible use cases and describe
> the hardware and the requirements.
> The interrupt is not a hard requirement for the timer to function in a
> specific way.
> Thus, choose to remove the interrupts property from the mandatory list of
> properties.
> 

The correct hardware description is that the interrupt is present on the
IP. Having software behave differently depending on the presence of that
property is configuration, not hardware description.

> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> ---
>  .../devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml  | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml b/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
> index 597d67fba92f..27f78459b892 100644
> --- a/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
> +++ b/Documentation/devicetree/bindings/soc/microchip/atmel,at91rm9200-tcb.yaml
> @@ -134,7 +134,6 @@ allOf:
>  required:
>    - compatible
>    - reg
> -  - interrupts
>    - clocks
>    - clock-names
>    - '#address-cells'
> -- 
> 2.25.1
> 

-- 
Alexandre Belloni, co-owner and COO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com