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Date:   Tue, 15 Dec 2020 10:32:12 -0600
From:   Rob Herring <robh@kernel.org>
To:     Icenowy Zheng <icenowy@aosc.io>
Cc:     Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org, Mark Brown <broonie@kernel.org>,
        linux-spi@vger.kernel.org
Subject: Re: [RFC PATCH 10/12] dt-bindings: spi: sun6i: add compatible for
 V831 SPI
Message-ID: <20201215163212.GA3972588@robh.at.kernel.org>
References: <20201212040157.3639864-1-icenowy@aosc.io>
 <20201212051202.3645115-1-icenowy@aosc.io>
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In-Reply-To: <20201212051202.3645115-1-icenowy@aosc.io>
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On Sat, Dec 12, 2020 at 01:12:00PM +0800, Icenowy Zheng wrote:
> V831 has a SPI controller similar to the H6 one.
> 
> Add a compatible string for it.
> 
> Cc: Mark Brown <broonie@kernel.org>
> Cc: linux-spi@vger.kernel.org
> Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
> ---
> H6 and V831 SPI controllers is not totally the same with H3: they have
> QSPI support added. Here V831 compatible string is just added in
> parallel with H6 one, but maybe we should make H6 SPI do not fallback to
> H3 one, and add H6 one as fallback to V831?

A fallback is really only needed if there's a user you expect to work 
unmodified. For example, say a new DMA mode is added, but that's 
something a bootloader wouldn't use. Given QSPI mode is probably 
fundamentally different?, then a fallback is probably not needed.

> 
>  .../devicetree/bindings/spi/allwinner,sun6i-a31-spi.yaml         | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/Documentation/devicetree/bindings/spi/allwinner,sun6i-a31-spi.yaml b/Documentation/devicetree/bindings/spi/allwinner,sun6i-a31-spi.yaml
> index 7866a655d81c..a620ff30033e 100644
> --- a/Documentation/devicetree/bindings/spi/allwinner,sun6i-a31-spi.yaml
> +++ b/Documentation/devicetree/bindings/spi/allwinner,sun6i-a31-spi.yaml
> @@ -24,6 +24,7 @@ properties:
>        - items:
>            - enum:
>                - allwinner,sun8i-r40-spi
> +              - allwinner,sun8i-v831-spi
>                - allwinner,sun50i-h6-spi
>            - const: allwinner,sun8i-h3-spi
>  
> -- 
> 2.28.0