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From:   Jernej =?utf-8?B?xaBrcmFiZWM=?= <jernej.skrabec@siol.net>
To:     Maxime Ripard <mripard@kernel.org>
Cc:     Rob Herring <robh+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Mark Rutland <mark.rutland@arm.com>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@lists.infradead.org>, devicetree@vger.kernel.org,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] dt-bindings: arm: sunxi: add OrangePi 3 with eMMC
Date:   Thu, 16 Jan 2020 17:33:45 +0100
Message-ID: <12435330.uLZWGnKmhe@jernej-laptop>
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Dne četrtek, 16. januar 2020 ob 13:29:44 CET je Maxime Ripard napisal(a):
> On Thu, Jan 16, 2020 at 12:10:58AM +0100, Jernej Škrabec wrote:
> > Hi!
> > 
> > Dne sreda, 15. januar 2020 ob 22:57:31 CET je Rob Herring napisal(a):
> > > On Wed, Jan 15, 2020 at 1:42 PM Jernej Skrabec <jernej.skrabec@siol.net>
> > 
> > wrote:
> > > > OrangePi 3 can optionally have eMMC. Add a compatible for it.
> > > 
> > > Is this just a population option or a different board layout? If the
> > > former, I don't think you need a new compatible, just add/enable a
> > > node for the eMMC.
> > 
> > I have only board with eMMC but I imagine it's the former. Even so,
> > current
> > approach with Allwinner boards is to have two different board DT files,
> > one for each variant. This can be seen from
> > Documentation/devicetree/bindings/arm/ sunxi.yaml which has a lot of
> > compatibles ending with "-emmc". I guess reason for that is to avoid
> > having MMC controller being powered on for no reason.
> The main reason for that is that those populating options can be
> conflicting. For example, last week we discussed an issue about the
> eMMC being on the same pin set than an SPI flash, both options being
> available.
> 
> The solution Andre suggested then was to let the eMMC be disabled, and
> have the bootloader probe the emmc, and if found, enable
> it. Otherwise, it means that you have a SPI flash (and enable it).
> 
> I guess a similar solution would apply here.

From what I can tell from schematic, pins are dedicated for eMMC.

So what solution do you suggest? Put eMMC node in original OrangePi 3 DT and 
set status to disabled?

Best regards,
Jernej