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

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Date:   Mon, 28 Oct 2019 17:12:50 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     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

On Tue, Oct 29, 2019 at 12:56:26AM +0100, Ondřej Jirman wrote:
> 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?

I think it is perfectly fine to continue using enable_irq_wake and
disable_irq_wake from the driver while marking irq as being wake irq
form the core.

Thanks.

-- 
Dmitry