linux-kernel - Re: [PATCH v3 1/2] input: touchscreen: pixcir_i2c_ts: Add support for optional wakeup interrupt

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Message-ID: <20150727212042.GD5144@dtor-ws>
Date:	Mon, 27 Jul 2015 14:20:42 -0700
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Vignesh R <vigneshr@...com>
Cc:	Roger Quadros <rogerq@...com>, Tony Lindgren <tony@...mide.com>,
	Benoit Cousson <bcousson@...libre.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Russell King <linux@....linux.org.uk>,
	Henrik Rydberg <rydberg@...math.org>,
	Frodo Lai <frodo.lai@...il.com>,
	Jingoo Han <jg1.han@...sung.com>, linux-omap@...r.kernel.org,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH v3 1/2] input: touchscreen: pixcir_i2c_ts: Add support
 for optional wakeup interrupt

On Mon, Jul 27, 2015 at 04:49:22PM +0530, Vignesh R wrote:
> 
> 
> On 07/27/2015 04:19 PM, Roger Quadros wrote:
> > Hi,
> > 
> > On 23/07/15 17:54, Vignesh R wrote:
> >> On am437x-gp-evm, pixcir touchscreen can wake the system from low power
> >> state by generating wake-up interrupt via pinctrl and IO daisy chain.
> >> Add support for optional wakeup interrupt source by regsitering to
> >> automated wake IRQ framework introduced by commit 4990d4fe327b ("PM /
> >> Wakeirq: Add automated device wake IRQ handling").
> >> This is similar in approach to commit 2a0b965cfb6e ("serial: omap: Add
> >> support for optional wake-up")
> >>
> >> Signed-off-by: Vignesh R <vigneshr@...com>
> >> ---
> >>
> >> v3:
> >>  * handle error code returned by of_irq_get_byname()
> >>
> >> v2:
> >>  * use of_irq_get_byname()
> >>  * remove enable/disable_wake_irq()
> >>
> >>  drivers/input/touchscreen/pixcir_i2c_ts.c | 22 ++++++++++++++++++----
> >>  include/linux/input/pixcir_ts.h           |  1 +
> >>  2 files changed, 19 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
> >> index 8f3e243a62bf..3a4ab358bf52 100644
> >> --- a/drivers/input/touchscreen/pixcir_i2c_ts.c
> >> +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c
> >> @@ -29,6 +29,8 @@
> >>  #include <linux/of.h>
> >>  #include <linux/of_gpio.h>
> >>  #include <linux/of_device.h>
> >> +#include <linux/of_irq.h>
> >> +#include <linux/pm_wakeirq.h>
> >>  
> >>  #define PIXCIR_MAX_SLOTS       5 /* Max fingers supported by driver */
> >>  
> >> @@ -364,8 +366,6 @@ static int __maybe_unused pixcir_i2c_ts_suspend(struct device *dev)
> >>  				goto unlock;
> >>  			}
> >>  		}
> >> -
> >> -		enable_irq_wake(client->irq);
> >>  	} else if (input->users) {
> >>  		ret = pixcir_stop(ts);
> >>  	}
> >> @@ -386,8 +386,6 @@ static int __maybe_unused pixcir_i2c_ts_resume(struct device *dev)
> >>  	mutex_lock(&input->mutex);
> >>  
> >>  	if (device_may_wakeup(&client->dev)) {
> >> -		disable_irq_wake(client->irq);
> >> -
> >>  		if (!input->users) {
> >>  			ret = pixcir_stop(ts);
> >>  			if (ret) {
> >> @@ -445,6 +443,13 @@ static struct pixcir_ts_platform_data *pixcir_parse_dt(struct device *dev)
> >>  	dev_dbg(dev, "%s: x %d, y %d, gpio %d\n", __func__,
> >>  		pdata->x_max + 1, pdata->y_max + 1, pdata->gpio_attb);
> >>  
> >> +	pdata->wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
> >> +	if (pdata->wakeirq < 0 && pdata->wakeirq != -ENODATA &&
> >> +	    pdata->wakeirq != -EINVAL) {
> >> +		dev_err(dev, "Failed to get wakeirq\n");
> >> +		return ERR_PTR(pdata->wakeirq);
> >> +	}
> >> +
> >>  	return pdata;
> >>  }
> >>  #else
> >> @@ -564,11 +569,20 @@ static int pixcir_i2c_ts_probe(struct i2c_client *client,
> >>  	i2c_set_clientdata(client, tsdata);
> >>  	device_init_wakeup(&client->dev, 1);
> >>  
> >> +	/* Register wakeirq */
> >> +	error = (pdata->wakeirq > 0) ?
> >> +		dev_pm_set_dedicated_wake_irq(dev, pdata->wakeirq) :
> >> +		dev_pm_set_wake_irq(dev, client->irq);
> > 
> > Can 0 be a valid wakeirq or client->irq?
> > If yes then this logic is broken.
> > 
> 
> AFAIK, IRQ 0 is always assigned to system timer interrupt (cannot find
> reliable source to quote).
> 
> > I would set wakeirq to -EINVAL or something if it is not available
> > during probe and check for that condition.
> > 
> 
> Not sure, if I understand you correctly
> pdata->wakeirq will have -ENODATA or -EINVAL(as returned by
> of_irq_get_byname()), if wakeirq is not available. Do you want me to
> check for these two conditions specifically rather than
> (pdata->wakeirq > 0) ?

0 is not really valid general IRQ number; I2C for example sets
client->irq to 0 when there is no IRQ.

BTW, what do you think about my patch pushing this into i2c core? Could
you try and see if it works for you?

Thanks.

-- 
Dmitry
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