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Commit 40c6b6b7 authored by Abhijeet Dharmapurikar's avatar Abhijeet Dharmapurikar
Browse files

devfreq: allow zero values in opp table 



commit ab8f58ad ("PM / devfreq: Set
min/max_freq when adding the devfreq device") introduces a change
where an error in finding the ceil or floor is returned as a
zero frequency. This return of zero is treated as error condition
from the callsites.

It is perfectly valid for a device to have a zero frequency, usually
it denotes a power collapse. This valid return of zero frequency ends
up being treated as an error condition.

Fix it.

Change-Id: I5eb6fa622d6fe09207746b96dce05d0b58b233dc
Signed-off-by: default avatarAbhijeet Dharmapurikar <adharmap@codeaurora.org>
parent b1d3f812

drivers/devfreq/devfreq.c

+22 −16
Original line number Diff line number Diff line
@@ -72,28 +72,28 @@ static struct devfreq *find_device_devfreq(struct device *dev) 
	return ERR_PTR(-ENODEV);

}



static unsigned long find_available_min_freq(struct devfreq *devfreq)

static long find_available_min_freq(struct devfreq *devfreq)

{

	struct dev_pm_opp *opp;

	unsigned long min_freq = 0;

	long min_freq = 0;



	opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);

	if (IS_ERR(opp))

		min_freq = 0;

		min_freq = PTR_ERR(opp);

	else

		dev_pm_opp_put(opp);



	return min_freq;

}



static unsigned long find_available_max_freq(struct devfreq *devfreq)

static long find_available_max_freq(struct devfreq *devfreq)

{

	struct dev_pm_opp *opp;

	unsigned long max_freq = ULONG_MAX;

	long max_freq = LONG_MAX;



	opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);

	if (IS_ERR(opp))

		max_freq = 0;

		max_freq = PTR_ERR(opp);

	else

		dev_pm_opp_put(opp);
@@ -494,20 +494,25 @@ static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, 
{

	struct devfreq *devfreq = container_of(nb, struct devfreq, nb);

	int ret;

	long freq;



	mutex_lock(&devfreq->lock);



	devfreq->scaling_min_freq = find_available_min_freq(devfreq);

	if (!devfreq->scaling_min_freq) {

	freq = find_available_min_freq(devfreq);

	if (freq < 0) {

		devfreq->scaling_min_freq = 0;

		mutex_unlock(&devfreq->lock);

		return -EINVAL;

	}

	devfreq->scaling_min_freq = freq;



	devfreq->scaling_max_freq = find_available_max_freq(devfreq);

	if (!devfreq->scaling_max_freq) {

	freq = find_available_max_freq(devfreq);

	if (freq < 0) {

		devfreq->scaling_max_freq = 0;

		mutex_unlock(&devfreq->lock);

		return -EINVAL;

	}

	devfreq->scaling_max_freq = freq;



	ret = update_devfreq(devfreq);

	mutex_unlock(&devfreq->lock);
@@ -562,6 +567,7 @@ struct devfreq *devfreq_add_device(struct device *dev, 
	struct devfreq *devfreq;

	struct devfreq_governor *governor;

	int err = 0;

	long freq;



	if (!dev || !profile || !governor_name) {

		dev_err(dev, "%s: Invalid parameters.\n", __func__);
@@ -606,21 +612,21 @@ struct devfreq *devfreq_add_device(struct device *dev, 
		mutex_lock(&devfreq->lock);

	}



	devfreq->scaling_min_freq = find_available_min_freq(devfreq);

	if (!devfreq->scaling_min_freq) {

	freq = find_available_min_freq(devfreq);

	if (freq < 0) {

		mutex_unlock(&devfreq->lock);

		err = -EINVAL;

		goto err_dev;

	}

	devfreq->min_freq = devfreq->scaling_min_freq;

	devfreq->min_freq = devfreq->scaling_min_freq = freq;



	devfreq->scaling_max_freq = find_available_max_freq(devfreq);

	if (!devfreq->scaling_max_freq) {

	freq = find_available_max_freq(devfreq);

	if (freq < 0) {

		mutex_unlock(&devfreq->lock);

		err = -EINVAL;

		goto err_dev;

	}

	devfreq->max_freq = devfreq->scaling_max_freq;

	devfreq->max_freq = devfreq->scaling_max_freq = freq;



	dev_set_name(&devfreq->dev, "%s", dev_name(dev));

	err = device_register(&devfreq->dev);