PM / devfreq: Set min/max_freq when adding the devfreq device

Prior to that, the min/max_freq of the devfreq device are always zero
before the user changes the min/max_freq through sysfs entries.
It might make the confusion for the min/max_freq.

This patch initializes the available min/max_freq by using the OPP
during adding the devfreq device.

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index a1c4ee818614..6a6f88bccdee 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -69,6 +69,34 @@ static struct devfreq *find_device_devfreq(struct device *dev)
         return ERR_PTR(-ENODEV);
 }
 
+static unsigned long find_available_min_freq(struct devfreq *devfreq)
+{
+        struct dev_pm_opp *opp;
+        unsigned long min_freq = 0;
+
+        opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
+        if (IS_ERR(opp))
+                min_freq = 0;
+        else
+                dev_pm_opp_put(opp);
+
+        return min_freq;
+}
+
+static unsigned long find_available_max_freq(struct devfreq *devfreq)
+{
+        struct dev_pm_opp *opp;
+        unsigned long max_freq = ULONG_MAX;
+
+        opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
+        if (IS_ERR(opp))
+                max_freq = 0;
+        else
+                dev_pm_opp_put(opp);
+
+        return max_freq;
+}
+
 /**
  * devfreq_get_freq_level() - Lookup freq_table for the frequency
  * @devfreq:    the devfreq instance
@@ -559,6 +587,20 @@ struct devfreq *devfreq_add_device(struct device *dev,
                 mutex_lock(&devfreq->lock);
         }
 
+        devfreq->min_freq = find_available_min_freq(devfreq);
+        if (!devfreq->min_freq) {
+                mutex_unlock(&devfreq->lock);
+                err = -EINVAL;
+                goto err_dev;
+        }
+
+        devfreq->max_freq = find_available_max_freq(devfreq);
+        if (!devfreq->max_freq) {
+                mutex_unlock(&devfreq->lock);
+                err = -EINVAL;
+                goto err_dev;
+        }
+
         dev_set_name(&devfreq->dev, "devfreq%d",
                                 atomic_inc_return(&devfreq_no));
         err = device_register(&devfreq->dev);