[PATCHv4 4/7] hwspinlock/core: add common OF helpers

[Josh Cartwright]

On Fri, Mar 14, 2014 at 03:12:26PM +0200, Ohad Ben-Cohen wrote:
> On Sun, Mar 2, 2014 at 10:19 PM, Bjorn Andersson <bjorn at kryo.se> wrote:
> > When introducing the ability to reference a hwspin lock via a phandle
> > in device tree it makes a big difference to be able to differ between
> > the case of "initialization failed" or "device not yet probed"; so
> > that the client knows if it should fail or retry later.
> 
> I'm not convinced.
> 
> The only advantage this brings is to avoid retrying in case a fatal
> error has occurred. Such fatal errors are extremely rare, and when
> they show up - extremely painful, and I suspect that optimizing them
> wouldn't be a big win.

So, are you suggesting that because fatal errors should be "extremely
rare", a consuming driver should just assume that if NULL is returned
from a hwspin_lock_request*() function that it was the "device not yet
probed" case that was hit?

Note that having the consumer/hwspinlock device relationship modeled in
devicetree introduces more potential failure cases...

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