PM / devfreq: Show the all available frequencies

The commit a76caf55e5b35 ("thermal: Add devfreq cooling") allows
the devfreq device to use the cooling device. When the cooling down
are required, the devfreq_cooling.c disables the OPP entry with
the dev_pm_opp_disable(). In result, 'available_frequencies'[1]
sysfs node never came to show the all available frequencies.
[1] /sys/class/devfreq/.../available_frequencies

So, this patch uses the 'freq_table' in the 'struct devfreq_dev_profile'
in order to show the all available frequencies.
- If 'freq_table' is NULL, devfreq core initializes them by using OPP values.
- If 'freq_table' is initialized, devfreq core just uses the 'freq_table'.

And this patch adds some comment about the sort way of 'freq_table'.

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

2 files changed, 8 insertions, 13 deletions

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index b2920cd2b78e..381f92e5e794 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1194,22 +1194,16 @@ static ssize_t available_frequencies_show(struct device *d,
                                           char *buf)
 {
         struct devfreq *df = to_devfreq(d);
-        struct device *dev = df->dev.parent;
-        struct dev_pm_opp *opp;
         ssize_t count = 0;
-        unsigned long freq = 0;
+        int i;
 
-        do {
-                opp = dev_pm_opp_find_freq_ceil(dev, &freq);
-                if (IS_ERR(opp))
-                        break;
+        mutex_lock(&df->lock);
 
-                dev_pm_opp_put(opp);
+        for (i = 0; i < df->profile->max_state; i++)
                 count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
-                                   "%lu ", freq);
-                freq++;
-        } while (1);
+                                "%lu ", df->profile->freq_table[i]);
 
+        mutex_unlock(&df->lock);
         /* Truncate the trailing space */
         if (count)
                 count--;
diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
index 997a9eb34191..19520625ea94 100644
--- a/include/linux/devfreq.h
+++ b/include/linux/devfreq.h
@@ -84,8 +84,9 @@ struct devfreq_dev_status {
  *                      from devfreq_remove_device() call. If the user
  *                      has registered devfreq->nb at a notifier-head,
  *                      this is the time to unregister it.
- * @freq_table: Optional list of frequencies to support statistics.
- * @max_state:  The size of freq_table.
+ * @freq_table:         Optional list of frequencies to support statistics
+ *                      and freq_table must be generated in ascending order.
+ * @max_state:          The size of freq_table.
  */
 struct devfreq_dev_profile {
         unsigned long initial_freq;