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Date:   Fri, 29 Jul 2022 19:33:47 +0300
From:   Ivan Bornyakov <i.bornyakov@metrotek.ru>
To:     Daniel =?utf-8?B?R2zDtmNrbmVy?= <dg@emlix.com>
Cc:     mdf@kernel.org, hao.wu@intel.com, yilun.xu@intel.com,
        trix@redhat.com, robh+dt@kernel.org,
        krzysztof.kozlowski+dt@linaro.org, linux-fpga@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        system@metrotek.ru,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Subject: Re: [PATCH v5 2/2] dt-bindings: fpga: add binding doc for ecp5-spi
 fpga mgr
Message-ID: <20220729163347.irqqqcvh2biliqg2@x260>
References: <20220719112335.9528-1-i.bornyakov@metrotek.ru>
 <20220719112335.9528-3-i.bornyakov@metrotek.ru>
 <20220729090123.GA28299@homes.emlix.com>
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On Fri, Jul 29, 2022 at 11:01:24AM +0200, Daniel Gl?ckner wrote:
> Hi,
> 
> On Tue, Jul 19, 2022 at 02:23:35PM +0300, Ivan Bornyakov wrote:
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - lattice,ecp5-fpga-mgr
> 
> Since this driver uses the same interface as the existing
> drivers/fpga/machxo2-spi.c driver, wouldn't it be advisable to use a
> similar compatible id, i.e. lattice,ecp5-slave-spi?
> 

To quote Krzysztof Kozlowski from v1 review:
 > Do not encode interface name in compatible so no "spi"

See https://lore.kernel.org/linux-fpga/044a9736-a4ec-c250-7755-c80a5bcbe38b@linaro.org/

> > +required:
> > +  - compatible
> > +  - reg
> > +  - program-gpios
> > +  - init-gpios
> > +  - done-gpios
> 
> I think some of the GPIOs can be made optional by reading the status
> register or using the refresh command, assuming the slave spi interface
> stayed enabled after previous programming and we are not dealing with
> several chained FPGAs. But that can of course be left as an exercise for
> other developers.

I would prefer the latter.