Re: [PATCH] ARM: tegra: add "nor-jedec" flash compatible binding

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On 05/08/2015 12:43 PM, Brian Norris wrote:
On Fri, May 08, 2015 at 10:00:12AM -0600, Stephen Warren wrote:
On 05/08/2015 12:21 AM, Rafał Miłecki wrote:
Starting with commits
8ff16cf ("Documentation: devicetree: m25p80: add "nor-jedec" binding")
1103b85 ("mtd: m25p80: bind to "nor-jedec" ID, for auto-detection")
we have "nor-jedec" binding indicating support for JEDEC identification.

The documentation looks quite incomplete. "nor-jedec" sounds like
it's intended to be something generic. As such, it should be
documented in e.g.
Documentation/devicetree/bindings/mtd/nor-jedec.txt, not buried in
one particular flash device's binding. If it's not intended to be
generic, why isn't the existing "winbond,w25q32dw" enough?

It is generic, though there are plenty of additional manufacturer/device
pairs that could go on top of it. m25p80 was (one of?) the first
supported, so the naming has been based on legacy, and we're in the
process of unwinding a bit of that. If it helps, we could move the doc
to .../mtd/spi-nor,nor-jedec.txt or something like that.

Yes, moving the documentation to a generic location would be appropriate in my opinion.

Equally, "nor-jedec" doesn't sound like the right name. It doesn't
differentiate between SPI and parallel NOR flash, which presumably
need different compatible values, since the programming model is
quite different, and the compatible value is supposed to
define/imply the SW-visible programming model.

It's definitely for SPI only. There was much discussion about this a
few months back. Somewhere along the way, it was mentioned that the
context (SPI slave is a child of SPI master) would make this clear. I'm
still not sure why we didn't end up with something more descriptive,
though, like "spi-nor,nor-jedec".

I'm open to change, as this binding is new in 4.1-rc1.

I don't believe compatible values should be interpreted according to context; compatible value matching isn't implemented that way AFAIK, and I'm not aware of any precedent for it to work that way.

Did the discussion involve the core DT maintainers? If so, whatever they decided can stick. Otherwise, the discussion should be rubn by them.
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