From: Rob Herring <robh@kernel.org>
To: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Boris Brezillon <boris.brezillon@free-electrons.com>,
Marek Vasut <marek.vasut@gmail.com>,
Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org,
Guochun Mao <guochun.mao@mediatek.com>,
Richard Weinberger <richard@nod.at>,
Russell King <linux@armlinux.org.uk>,
linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
Matthias Brugger <matthias.bgg@gmail.com>,
linux-mediatek@lists.infradead.org,
Cyrille Pitchen <cyrille.pitchen@atmel.com>,
Brian Norris <computersforpeace@gmail.com>,
David Woodhouse <dwmw2@infradead.org>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v1 2/2] arm: dts: mt2701: add nor flash node
Date: Wed, 18 Jan 2017 16:20:10 -0600 [thread overview]
Message-ID: <20170118222010.ivc6jxpnrumemvdf@rob-hp-laptop> (raw)
In-Reply-To: <20170117143650.5db87148@free-electrons.com>
On Tue, Jan 17, 2017 at 02:36:50PM +1100, Thomas Petazzoni wrote:
> Hello,
>
> (Side note: you guys should learn about stripping irrelevant parts of
> an e-mail when replying!)
>
> On Mon, 16 Jan 2017 09:40:32 +0100, Boris Brezillon wrote:
>
> > > Well this is OK I guess, but then you can also use "mediatek,mt8173-nor"
> > > as the oldest supported compatible and be done with it, no ? It looks a
> > > bit crappy though, I admit that ...
> >
> > Let's stop bikeshedding and wait for DT maintainers feedback
> > before taking a decision ;-).
> >
> > Rob, Mark, any opinion?
>
Sigh, is how to do compatibles really not yet understood?
> I agree that a clarification would be good. There are really two
> options:
>
> 1. Have two compatible strings in the DT, the one that matches the
> exact SoC where the IP is found (first compatible string) and the
> one that matches some other SoC where the same IP is found (second
> compatible string). Originally, Linux only supports the second
> compatible string in its device driver, but if it happens that a
> difference is found between two IPs that we thought were the same,
> we can add support for the first compatible string in the driver,
> with a slightly different behavior.
This. And no wildcards in the compatible string.
> 2. Have a single compatible string in the DT, matching the exact SoC
> where the IP is found. This involves adding immediately this
> compatible string in the corresponding driver.
I wouldn't object to this from a DT perspective as I have no clue
generally if IP blocks are "the same" or not. Subsystem maintainers will
object though.
> I've not really been able to figure out which of the two options is the
> most future-proof/appropriate.
They are both future-proof. #2 has the disadvantage of requiring a
kernel update for a new SoC.
Rob
next prev parent reply other threads:[~2017-01-18 22:20 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-13 7:13 [PATCH v1 0/2] add nor flash node for mt2701 Guochun Mao
2017-01-13 7:13 ` [PATCH v1 1/2] Documentation: mtk-quadspi: update DT bindings Guochun Mao
2017-01-13 14:13 ` Boris Brezillon
2017-01-18 22:08 ` Rob Herring
2017-01-13 7:13 ` [PATCH v1 2/2] arm: dts: mt2701: add nor flash node Guochun Mao
2017-01-13 12:49 ` Marek Vasut
2017-01-13 14:17 ` Boris Brezillon
2017-01-13 15:12 ` Matthias Brugger
2017-01-13 15:21 ` Boris Brezillon
2017-01-13 16:13 ` Marek Vasut
2017-01-13 16:28 ` Boris Brezillon
2017-01-13 16:44 ` Marek Vasut
2017-01-13 16:56 ` Boris Brezillon
2017-01-13 17:33 ` Marek Vasut
2017-01-14 8:29 ` Boris Brezillon
2017-01-15 0:23 ` Marek Vasut
2017-01-16 8:40 ` Boris Brezillon
2017-01-16 16:09 ` Marek Vasut
2017-01-17 3:36 ` Thomas Petazzoni
2017-01-18 22:20 ` Rob Herring [this message]
2017-01-18 23:38 ` Thomas Petazzoni
2017-01-19 2:51 ` Rob Herring
2017-01-19 8:14 ` Boris Brezillon
2017-01-19 14:18 ` Rob Herring
2017-01-22 2:36 ` Guochun Mao
2017-01-24 10:31 ` Boris Brezillon
2017-01-24 10:38 ` John Crispin
2017-01-19 7:53 ` Boris Brezillon
2017-01-17 3:32 ` Thomas Petazzoni
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