Re: [RFC PATCH 1/5] spi: introduce flag for memory mapped read

[Mark Brown <broonie@kernel.org>]

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On Thu, Aug 06, 2015 at 12:01:37PM +0200, Michal Suchanek wrote:

> However, I am familiar m25p80.c and as I understand it the controller
> is basically supposed to implement m25p80.c in hardware when this flag
> is set.

But what in concrete terms is that supposed to mean?  It's currently
just an essentially undocumented flag on a message rather than something
operating at the level of a flash chip.  That's pretty much where
Russell's comments come from.

> If I was using m25p80.c to talk to anything but an actual flash chip
> it would get me quite worried.

Sure, but at the end of the day it's just emitting standard SPI messages
which don't know anything about flash.  If those messages are a sensible
interface here then why bother with the flag, we can just pattern match
on the format of the message.  If that doesn't work then probably this
isn't a great interface and a separate, application specific interface
makes more sense.

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