Messages in this thread | | | Date | Tue, 19 May 2015 17:39:40 +0200 | From | Johan Hovold <> | Subject | Re: [PATCH] gpiolib: debugfs: display gpios requested as irq only |
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On Tue, May 19, 2015 at 04:12:35PM +0200, Linus Walleij wrote: > On Mon, May 18, 2015 at 5:17 PM, Grygorii.Strashko@linaro.org > <grygorii.strashko@linaro.org> wrote: > > On 05/18/2015 06:08 PM, Johan Hovold wrote: > > >> GPIOs 160-191, platform/4805d000.gpio, gpio: > >> gpio-171 (<irq-only> ) in hi IRQ-209 > > > > In general agree, but i propose to do it as > > GPIOs 160-191, platform/4805d000.gpio, gpio: > > gpio-171 ((null) ) in hi IRQ-209 <irq-only> > > > > My intention is - this interface could be considered as more or less stable, so > > it is better to add additional information at the end of each line to avoid > > potential breakage of User space SW (test/debug scripts). > > What? If I wanted a stable interface I would use sysfs and document > the ABI in Documentation/ABI/*. > > debugfs is not ABI.
As I mentioned in my response to Grygorii, not everyone -- and most notably apparently not even Linus Torvalds -- agrees on this:
"The fact that something is documented (whether correctly or not) has absolutely _zero_ impact on anything at all. What makes something an ABI is that it's useful and available. The only way something isn't an ABI is by _explicitly_ making sure that it's not available even by mistake in a stable form for binary use.
Example: kernel internal data structures and function calls. We make sure that you simply _cannot_ make a binary that works across kernel versions. That is the only way for an ABI to not form."
https://lwn.net/Articles/309298/
In this case, it could be worked around by providing another debugfs file with gpios used as IRQs, I guess.
Johan
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