PM / devfreq: Do not show statistics if it's not ready.

Before this patch for a device without statistics support,

$ cat trans_stat
    From  :   To
          :   time(ms)
Total transitions : 0
$

After this patch applied for such a device,

$ cat trans_stat
Not Supported.
$

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index d36fa2d..984c5e9 100644 (file)
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -1049,6 +1049,8 @@ static ssize_t trans_stat_show(struct device *dev,
        if (!devfreq->stop_polling &&
                        devfreq_update_status(devfreq, devfreq->previous_freq))
                return 0;
+       if (max_state == 0)
+               return sprintf(buf, "Not Supported.\n");
 
        len = sprintf(buf, "     From  :   To\n");
        len += sprintf(buf + len, "           :");