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From:   Maxim Kiselev <bigunclemax@gmail.com>
Date:   Sat, 6 May 2023 16:59:36 +0400
Message-ID: <CALHCpMhp07DwL+cUZN8rwa1N_PHQ1KstOB+Gw_mCWFzm5rSVrQ@mail.gmail.com>
Subject: Re: [PATCH v2 1/6] dt-bindings: spi: sun6i: add DT bindings for
 Allwinner R329 SPI
To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     Andre Przywara <andre.przywara@arm.com>,
        Icenowy Zheng <icenowy@aosc.io>,
        Mark Brown <broonie@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Chen-Yu Tsai <wens@csie.org>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        Samuel Holland <samuel@sholland.org>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Cristian Ciocaltea <cristian.ciocaltea@collabora.com>,
        Heiko Stuebner <heiko.stuebner@vrull.eu>,
        Maxime Ripard <mripard@kernel.org>, linux-spi@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org,
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> Should this not be set up as a fallback compatible, per Samuel's
> suggestion here:

Ok, I'll do it in the next version.

> I wonder what is the difference of DBI compatible. You refer to "helper
> functions", which sounds like driver... do you mean some parts of SPI
> controller?

According to the D1 datasheet the SPI_DBI controller uses the same
registers layout as the regular SPI0 controller.
But also it has an additional DBI mode functionality. Support for this
mode is not yet implemented.
So there is no difference between 'sun50i-r329-spi' and
'sun50i-r329-spi-dbi' controllers types in the SPI driver.

Maybe we should drop 'sun50i-r329-spi-dbi' compatible struct from here
https://lore.kernel.org/lkml/20230506073018.1411583-5-bigunclemax@gmail.com/
for a while the DBI mode functionality will not be implemented?