linux-kernel - Re: [PATCH] input: sun4i-lradc-keys: Add wakup support

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Date:   Tue, 29 Oct 2019 00:56:26 +0100
From:   Ondřej Jirman <megous@...ous.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     linux-sunxi@...glegroups.com, Hans de Goede <hdegoede@...hat.com>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>,
        "open list:SUN4I LOW RES ADC ATTACHED TABLET KEYS DRIVER" 
        <linux-input@...r.kernel.org>,
        "moderated list:ARM/Allwinner sunXi SoC support" 
        <linux-arm-kernel@...ts.infradead.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] input: sun4i-lradc-keys: Add wakup support

Hello Dmitry,

On Mon, Oct 28, 2019 at 04:38:28PM -0700, Dmitry Torokhov wrote:
> Hi Ondrej,
> 
> On Mon, Oct 28, 2019 at 11:15:02PM +0100, Ondrej Jirman wrote:
> > Allow the driver to wakeup the system on key press.
> > 
> > Signed-off-by: Ondrej Jirman <megous@...ous.com>
> > ---
> >  drivers/input/keyboard/sun4i-lradc-keys.c | 22 ++++++++++++++++++----
> >  1 file changed, 18 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/input/keyboard/sun4i-lradc-keys.c b/drivers/input/keyboard/sun4i-lradc-keys.c
> > index 4a796bed48ac..bba679d7b54b 100644
> > --- a/drivers/input/keyboard/sun4i-lradc-keys.c
> > +++ b/drivers/input/keyboard/sun4i-lradc-keys.c
> > @@ -22,6 +22,8 @@
> >  #include <linux/module.h>
> >  #include <linux/of_platform.h>
> >  #include <linux/platform_device.h>
> > +#include <linux/pm_wakeirq.h>
> > +#include <linux/pm_wakeup.h>
> >  #include <linux/regulator/consumer.h>
> >  #include <linux/slab.h>
> >  
> > @@ -226,8 +228,7 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
> >  {
> >  	struct sun4i_lradc_data *lradc;
> >  	struct device *dev = &pdev->dev;
> > -	int i;
> > -	int error;
> > +	int i, error, irq;
> >  
> >  	lradc = devm_kzalloc(dev, sizeof(struct sun4i_lradc_data), GFP_KERNEL);
> >  	if (!lradc)
> > @@ -272,8 +273,13 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
> >  	if (IS_ERR(lradc->base))
> >  		return PTR_ERR(lradc->base);
> >  
> > -	error = devm_request_irq(dev, platform_get_irq(pdev, 0),
> > -				 sun4i_lradc_irq, 0,
> > +	irq = platform_get_irq(pdev, 0);
> > +	if (irq < 0) {
> > +		dev_err(&pdev->dev, "Failed to get IRQ\n");
> > +		return irq;
> > +	}
> > +
> > +	error = devm_request_irq(dev, irq, sun4i_lradc_irq, 0,
> >  				 "sun4i-a10-lradc-keys", lradc);
> >  	if (error)
> >  		return error;
> > @@ -282,6 +288,14 @@ static int sun4i_lradc_probe(struct platform_device *pdev)
> >  	if (error)
> >  		return error;
> >  
> > +	device_init_wakeup(dev, true);
> 
> I do not think we want to do this unconditionally. Can we maybe key off
> "wakeup-source" device property.

Sure thing.

> > +
> > +	error = dev_pm_set_wake_irq(dev, irq);
> > +	if (error) {
> > +		dev_err(dev, "Could not set wake IRQ\n");
> > +		return error;
> > +	}
> > +
> 
> I wonder if we could teach platform driver core to handle this for us.

Not sure, some drivers do enable/disable wake_irq by hand in suspend/resume
callbacks, so it would probably need to be opt-in somehow. I guess calling the
function like this is one way to make it opt-in.

The other way may be by passing a flag somewhere, like to
request_threaded_irq. Did you have something more concrete in mind?

regards,
	o.

> Thanks.
> 
> -- 
> Dmitry