Commit 50a5b33e authored by Nishanth Menon's avatar Nishanth Menon Committed by MyungJoo Ham
Browse files

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: default avatarNishanth Menon <nm@ti.com>
Signed-off-by: default avatarMyungJoo Ham <myungjoo.ham@samsung.com>
parent 0359d1af

Documentation/ABI/testing/sysfs-class-devfreq

+7 −0
Original line number Diff line number Diff line
@@ -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.

drivers/devfreq/devfreq.c

+22 −0
Original line number Diff line number Diff line
@@ -730,6 +730,27 @@ static ssize_t store_governor(struct device *dev, struct device_attribute *attr, 
		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),