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PM / devfreq: Add sysfs node to expose available governors 

Now that governor list can be variable, knowing the available governors
is useful to be able to select a governor using relevant sysfs node.

Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Kevin Hilman <khilman@ti.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
This commit is contained in:
Nishanth Menon 2012-10-29 15:01:48 -05:00 committed by MyungJoo Ham
parent 0359d1afe4
commit 50a5b33e01
2 changed files with 29 additions and 0 deletions
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7
Documentation/ABI/testing/sysfs-class-devfreq
View File

@ -71,3 +71,10 @@ Description:
the available frequencies of the corresponding devfreq object.
This is a snapshot of available frequencies and not limited
by the min/max frequency restrictions.
What: /sys/class/devfreq/.../available_governors
Date: October 2012
Contact: Nishanth Menon <nm@ti.com>
Description:
The /sys/class/devfreq/.../available_governors shows
currently available governors in the system.

22
drivers/devfreq/devfreq.c
View File

@ -730,6 +730,27 @@ out:
ret = count;
return ret;
}
static ssize_t show_available_governors(struct device *d,
struct device_attribute *attr,
char *buf)
{
struct devfreq_governor *tmp_governor;
ssize_t count = 0;
mutex_lock(&devfreq_list_lock);
list_for_each_entry(tmp_governor, &devfreq_governor_list, node)
count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
"%s ", tmp_governor->name);
mutex_unlock(&devfreq_list_lock);
/* Truncate the trailing space */
if (count)
count--;
count += sprintf(&buf[count], "\n");
return count;
}
static ssize_t show_freq(struct device *dev,
struct device_attribute *attr, char *buf)
@ -917,6 +938,7 @@ static ssize_t show_trans_table(struct device *dev, struct device_attribute *att
static struct device_attribute devfreq_attrs[] = {
__ATTR(governor, S_IRUGO | S_IWUSR, show_governor, store_governor),
__ATTR(available_governors, S_IRUGO, show_available_governors, NULL),
__ATTR(cur_freq, S_IRUGO, show_freq, NULL),
__ATTR(available_frequencies, S_IRUGO, show_available_freqs, NULL),
__ATTR(target_freq, S_IRUGO, show_target_freq, NULL),