Re: [PATCH] gpiolib: debugfs: display gpios requested as irq only

From: Linus Walleij
Date: Wed May 20 2015 - 03:21:21 EST


On Tue, May 19, 2015 at 5:39 PM, Johan Hovold <johan@xxxxxxxxxx> wrote:
> On Tue, May 19, 2015 at 04:12:35PM +0200, Linus Walleij wrote:

>> 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:

Yeah I was sloppy I guess.

What I mean, precisely is that sysfs is ABI, whether documented or
not.

Even debugfs is actually blurry, as per
Documentation/filesystems/debugfs.txt:

"The debugfs filesystem is also intended to not serve as a stable
ABI to user space; in theory, there are no stability constraints placed on
files exported there. The real world is not always so simple, though [1];
even debugfs interfaces are best designed with the idea that they will need
to be maintained forever."

But I haven't been bitten by it yet so that's why I allow some poetic
license.

Yours,
Linus Walleij
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