Re: [PATCH] gpiolib: Avoid side effects in gpio_is_visible()

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, May 15, 2023 at 12:27 AM Chris Packham
<Chris.Packham@xxxxxxxxxxxxxxxxxxx> wrote:

> In my original case which is a kernel module that exports a GPIO for
> userspace using gpiod_export()

We should not add new users for that API as it increase the usage
of the sysfs ABI but if it's an existing in-tree usecase I buy it.

> The crux of the problem is that the irq_desc is created when it hasn't
> been requested.

The right solution to me seems to be to not use gpiod_export()
and not use sysfs TBH.

> In some cases we know the GPIO pin is an output so we
> could avoid it, in others we could delay the creation until an interrupt
> is actually requested (which is what I'm attempting to do).

Yeah I guess. If we wanna keep papering over issues created
by the sysfs ABI.

Yours,
Linus Walleij