Re: [PATCH 2/2] input: egalax_ts: free irq resource before request the line as GPIO

[Andy Shevchenko <andy.shevchenko@gmail.com>]

On Sun, Apr 19, 2020 at 9:10 PM Dmitry Torokhov
<dmitry.torokhov@gmail.com> wrote:
>
> On Tue, Mar 10, 2020 at 07:15:35AM +0000, BOUGH CHEN wrote:
> >
> > > From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > Sent: 2020年3月10日 12:27
> > > To: BOUGH CHEN <haibo.chen@nxp.com>
> > > Cc: linux-input@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>
> > > Subject: Re: [PATCH 2/2] input: egalax_ts: free irq resource before request
> > > the line as GPIO
> > >
> > > On Tue, Feb 11, 2020 at 04:41:12PM +0800, haibo.chen@nxp.com wrote:
> > > > From: Haibo Chen <haibo.chen@nxp.com>
> > > >
> > > > + egalax_free_irq(ts);
> > >
> > > It sounds to me you want simply disable interrupts in suspend. Does not
> > > calling disable_irq() here suffice?
> >
>
> > Here why I want to disable interrupts here is because in the newest
> > gpio system, if the gpio is request as an irq, it can't be request as
> > a gpio anymore.  In the function egalax_wake_up_device(), we need to
> > request the irq pin as a gpio for a while, generate a signal to wake
> > up the device. So before request the pad as gpio, need first free irq
> > resource.
>
> This seems like a fairly common pattern and I wonder if our GPIO
> overlords can help us here.
>
> Linus, Mika, Andy, would it be possible to have an API that would allow
> driver to temporarily "take over" GPIO that is used for interrupts and
> drive it as output without resorting to freeing and re-acquiring irq?
> I.e. something like gpiod_irq_drive_output_start() and
> gpiod_irq_drive_output_end()?

Shouldn't it be handled by pinctrl states? sleep state / default state / etc?


-- 
With Best Regards,
Andy Shevchenko