PM / devfreq: add min/max_freq limit requested by users.
The frequency requested to devfreq device driver from devfreq governors
is restricted by min_freq and max_freq input.
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index c189b82..a129a7b 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -501,12 +501,82 @@
!to_devfreq(dev)->governor->no_central_polling);
}
+static ssize_t store_min_freq(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long value;
+ int ret;
+ unsigned long max;
+
+ ret = sscanf(buf, "%lu", &value);
+ if (ret != 1)
+ goto out;
+
+ mutex_lock(&df->lock);
+ max = df->max_freq;
+ if (value && max && value > max) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ df->min_freq = value;
+ update_devfreq(df);
+ ret = count;
+unlock:
+ mutex_unlock(&df->lock);
+out:
+ return ret;
+}
+
+static ssize_t show_min_freq(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq);
+}
+
+static ssize_t store_max_freq(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long value;
+ int ret;
+ unsigned long min;
+
+ ret = sscanf(buf, "%lu", &value);
+ if (ret != 1)
+ goto out;
+
+ mutex_lock(&df->lock);
+ min = df->min_freq;
+ if (value && min && value < min) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ df->max_freq = value;
+ update_devfreq(df);
+ ret = count;
+unlock:
+ mutex_unlock(&df->lock);
+out:
+ return ret;
+}
+
+static ssize_t show_max_freq(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq);
+}
+
static struct device_attribute devfreq_attrs[] = {
__ATTR(governor, S_IRUGO, show_governor, NULL),
__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
__ATTR(central_polling, S_IRUGO, show_central_polling, NULL),
__ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval,
store_polling_interval),
+ __ATTR(min_freq, S_IRUGO | S_IWUSR, show_min_freq, store_min_freq),
+ __ATTR(max_freq, S_IRUGO | S_IWUSR, show_max_freq, store_max_freq),
{ },
};