[PATCH v5 5/7] PM / devfreq: Show the all available frequencies

[Chanwoo Choi]

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.c...@samsung.com>
Acked-by: MyungJoo Ham <myungjoo....@samsung.com>
---
 drivers/devfreq/devfreq.c | 16 +++++-----------
 include/linux/devfreq.h   |  5 +++--
 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;
-- 
1.9.1