Subject: [PATCH RFT V2 3/3] iio: mxs-lradc: implement suspend/resume support

From: [email-masked] (Stefan Wahren)
Date: Fri, 22 Apr 2016 15:57:12 +0200

Hi Marek,

Am 21.04.2016 um 22:45 schrieb Marek Vasut:
> On 04/21/2016 10:11 PM, Stefan Wahren wrote:
>> This patch implements suspend/resume support for mxs-lradc.
>> It's possible to use the touchscreen as wakeup source.
>>
>> Signed-off-by: Stefan Wahren <[email-masked]>
>> ---
>>  drivers/iio/adc/mxs-lradc.c |   61 +++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 61 insertions(+)
>>
>> diff --git a/drivers/iio/adc/mxs-lradc.c b/drivers/iio/adc/mxs-lradc.c
>> index cfc558f..6bd387f 100644
>> --- a/drivers/iio/adc/mxs-lradc.c
>> +++ b/drivers/iio/adc/mxs-lradc.c
>> @@ -29,6 +29,7 @@
>>  #include <linux/of.h>
>>  #include <linux/of_device.h>
>>  #include <linux/platform_device.h>
>> +#include <linux/pm.h>
>>  #include <linux/slab.h>
>>  #include <linux/stmp_device.h>
>>  #include <linux/sysfs.h>
>> @@ -1745,10 +1746,70 @@ static int mxs_lradc_remove(struct platform_device *pdev)
>>  	return 0;
>>  }
>>  
>> +static int __maybe_unused mxs_lradc_suspend(struct device *dev)
>> +{
>> +	struct iio_dev *iio = dev_get_drvdata(dev);
>> +	struct mxs_lradc *lradc = iio_priv(iio);
>> +	struct input_dev *input = lradc->ts_input;
> Can lradc->ts_input contain some non-valid pointer ? You should make
> sure it's either inited to NULL or valid pointer, which I'm not sure
> you do.

the whole content of lradc get initialized with zero by
devm_iio_device_alloc.

Or do you mean the error case that input registration failed and a
suspend occur (if it's possible)|?

Stefan

|
>
>> +	int ret = 0;
>> +
>> +	if (input) {
>> +		mutex_lock(&input->mutex);
>> +
>> +		/* Enable touchscreen wakeup irq */
>> +		if (input->users && device_may_wakeup(dev))
>> +			ret = enable_irq_wake(lradc->irq[0]);
>> +		else
>> +			mxs_lradc_disable_ts(lradc);
>> +
>> +		mutex_unlock(&input->mutex);
>> +	}
>> +
>> +	if (ret)
>> +		return ret;
>> +
>> +	mxs_lradc_hw_stop(lradc);
>> +
>> +	clk_disable_unprepare(lradc->clk);
>> +
>> +	return ret;
>> +}
>> +
>> +static int __maybe_unused mxs_lradc_resume(struct device *dev)
>> +{
>> +	struct iio_dev *iio = dev_get_drvdata(dev);
>> +	struct mxs_lradc *lradc = iio_priv(iio);
>> +	struct input_dev *input = lradc->ts_input;
>> +	int ret;
>> +
>> +	ret = clk_prepare_enable(lradc->clk);
>> +	if (ret)
>> +		return ret;
>> +
>> +	mxs_lradc_hw_init(lradc);
>> +
>> +	if (input) {
>> +		mutex_lock(&input->mutex);
>> +
>> +		/* Disable touchscreen wakeup irq */
>> +		if (input->users && device_may_wakeup(dev))
>> +			ret = disable_irq_wake(lradc->irq[0]);
>> +		else
>> +			mxs_lradc_enable_touch_detection(lradc);
>> +
>> +		mutex_unlock(&input->mutex);
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static SIMPLE_DEV_PM_OPS(mxs_lradc_pm_ops, mxs_lradc_suspend, mxs_lradc_resume);
>> +
>>  static struct platform_driver mxs_lradc_driver = {
>>  	.driver	= {
>>  		.name	= DRIVER_NAME,
>>  		.of_match_table = mxs_lradc_dt_ids,
>> +		.pm	= &mxs_lradc_pm_ops,
>>  	},
>>  	.probe	= mxs_lradc_probe,
>>  	.remove	= mxs_lradc_remove,
>>
> Looks OK otherwise:
>
> Reviewed-by: Marek Vasut <[email-masked]>
>