linux-kernel - Re: [PATCH v5 4/4] gpio: rockchip: Set input direction when request irq

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Message-ID: <CAMRc=MdY1idv1o_nZFb1fKLpM5DHCPmEu5t5MMa_kV9csLgQWw@mail.gmail.com>
Date: Tue, 12 Nov 2024 13:53:48 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc: Ye Zhang <ye.zhang@...k-chips.com>, linus.walleij@...aro.org, heiko@...ech.de, 
	linux-gpio@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, 
	linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org, 
	mika.westerberg@...ux.intel.com, tao.huang@...k-chips.com, 
	finley.xiao@...k-chips.com, tim.chen@...k-chips.com, 
	elaine.zhang@...k-chips.com, 
	Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH v5 4/4] gpio: rockchip: Set input direction when request irq

On Tue, Nov 12, 2024 at 1:50 PM Bartosz Golaszewski <brgl@...ev.pl> wrote:
>
> On Tue, Nov 12, 2024 at 11:40 AM Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> >
> > On Tue, Nov 12, 2024 at 09:48:06AM +0100, Bartosz Golaszewski wrote:
> > > On Tue, Nov 12, 2024 at 2:54 AM Ye Zhang <ye.zhang@...k-chips.com> wrote:
> > > >
> > > > Since the GPIO can only generate interrupts when its direction is set to
> > > > input, it is set to input before requesting the interrupt resources.
> >
> > ...
> >
> > > This looks like a fix to me, do you want it sent for stable? If so,
> > > please add the Fixes tag and put it first in the series.
> >
> > Independently on the resolution on this, can the first three be applied to
> > for-next? I think they are valuable from the documentation perspective as
> > it adds the explanation of the version register bit fields.
> >
> > The last one seems to me independent (code wise, meaning no potential
> > conflicts) to the rest and may be applied to for-current later on.
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
> >
> >
>
> There's another issue I see with this patch. It effectively changes
> the pin's direction behind the back of the GPIOLIB. If a GPIO is
> requested, its direction set to output and another orthogonal user
> requests the same pin as input, we'll never update the FLAG_IS_OUT

I meant to say "same pin as interrupt". Sorry for the noise.

Bart

> value and I don't think any subsequent behavior can be considered
> defined.
>
> I applied the first 3 patches as they look alright.
>
> Bart