Re: [REGRESSION] gpio hogging fails with pinctrl gpio drivers

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Thu, Feb 6, 2020 at 6:33 PM Russell King - ARM Linux admin
<linux@xxxxxxxxxxxxxxx> wrote:

> It seems that sometime between 4.20 and 5.5, something has broken the
> ability to specify gpio-hogs in DT for GPIOs that are written around
> pinctrl drivers.
(explanation that makes perfect sense)
> Consequently, adding a gpio-hog to DT for this driver results in the
> driver endlessly returning -EPROBE_DEFER.

I suspect this is sx150x-specific and suspect these two commits:

1a1d39e1b8dd pinctrl: sx150x: Register pinctrl before adding the gpiochip
b930151e5b55 pinctrl: sx150x: Add a static gpio/pinctrl pin range mapping

I suppose people weren't using hogs very much with the sx150x and
it didn't turn up in testing so far.

I don't think for example pinctrl-stmfx.c has this problem, as it registers
the pin ranges from the device tree as part of the core code.
But other drivers calling gpiochip_add_pin_range() may be experiencing
this.

Peter/Andrey, do you have some idea? Have you tested this usecase (hogs)
with the sx150x?

Yours,
Linus Walleij