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

From: Vignesh R <vigneshr@ti.com>
To: Roger Quadros <rogerq@ti.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Tony Lindgren <tony@atomide.com>,
	Benoit Cousson <bcousson@baylibre.com>,
	Rob Herring <robh+dt@kernel.org>, Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	Russell King <linux@arm.linux.org.uk>
Cc: Henrik Rydberg <rydberg@bitmath.org>,
	Frodo Lai <frodo.lai@gmail.com>, Jingoo Han <jg1.han@samsung.com>,
	<linux-omap@vger.kernel.org>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <linux-input@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] input: touchscreen: pixcir_i2c_ts: Add support for optional wakeup interrupt
Date: Mon, 27 Jul 2015 16:49:22 +0530	[thread overview]
Message-ID: <55B613BA.3070402@ti.com> (raw)
In-Reply-To: <55B60CA1.3090800@ti.com>

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@ti.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) ?

-- 
Regards
Vignesh