[PATCH v1 2/2] arm: dts: mt2701: add nor flash node
robh at kernel.org
Wed Jan 18 14:20:10 PST 2017
On Tue, Jan 17, 2017 at 02:36:50PM +1100, Thomas Petazzoni wrote:
> (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
> 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
> 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.
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